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CT 05-20; STATE STREET CONDOMINIUMS; Storm Water Quality; 2005-12-21
PRELIMINARY STORM WATER MANAGEMENT PLAN For STATE STREET CONDOS Revised: December 21, 2005 Prepared: August 3, 2005 Prepared by: O'DAY CONSULTANTS, INC. 2710 Loker Avenue West, Suite 100 Carlsbad, California 92010-6609 Tel: (760)931-7700 Fax: (760)931-8680 George O'D RCE 32014 Exp. 12/31/06 Date PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS TABLE OF CONTENTS ITEM PAGE COVER SHEET 1 TABLE OF CONTENTS 1 1.0 INTRODUCTION 1 1.1 PURPOSE 1 1.2 LOCATION 1 1.3 ABBREVIATIONS 1 2.0 PROJECT REVIEW & PERMITTING PROCESS 1 2.1 DETERMINE APPLICABLE STORM WATER BMP REQUIREMENTS 2 2.2 PRIORITY PROJECT PERMANENT STORM WATER BMP REQUIREMENTS 2 2.3 STANDARD PERMANENT STORM WATER BMPS REQUIREMENTS 2 2.4 CONSTRUCTION CRITERIA 3 2.5 CONSTRUCTION SITE PRIORITY 3 2.6 STORM WATER STANDARDS TABLE 1 3 3.0 PREPARE AND SUBMIT APPROPRIATE PLANS 3 3.1 REQUIRED BMP ELEMENTS 3 3.2 OPTIONAL BMP ELEMENTS 4 3.3 TREATMENT CONTROL BMPS 4 4.0 PERMANENT BEST MANAGEMENT PRACTICES SELECTION 4 4.1 IDENTIFY POLLUTANTS FORM THE PROJECT AREA 4 4.1.1 ANTICIPATED POLLUTANTS OF CONCERN 4 4.1.2 POTENTIAL POLLUTANTS OF CONCERN 4 4.2 IDENTIFY POLLUTANTS OF CONCERN IN RECEIVING WATERS 5 4.2.1 IDENTIFY THE HYDROLOGIC UNIT CONTRIBUTION... 5 4.2.2 IDENTIFY 303(d) IMPAIRMENTS IN THE RECEIVING WATERS 5 4.3 BENEFICIAL USES OF RECEIVING WATERS 5 4.3.1 REC1-CONTACT RECREATION 5 4.3.2 REC2 - NON-CONTACT RECREATION 5 4.3.3 EST - ESTUARINE HABITAT 6 4.3.4 MAR-MARINE HABITAT 6 4.3.5 WILD-WILDLIFE HABITAT 6 4.3.6 RARE - RARE, THREATENED, OR ENDANGERED SPECIES 6 4.4 IDENTIFY CONDITIONS OF CONCERN 6 Revised December 16, 2005 - ii - 05-1117-5 August 3, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS TABLE OF CONTENTS (CONTINUED) ITEM PAGE 5.0 ESTABLISH PERMANENT STORM WATER BEST MANAGEMENT PRACTICES 6 5.1 SITE DESIGN BMPS 7 5.1.1 MAINTAIN PRE-DEVELOPMENT RAINFALL RUNOFF 7 CHARACTERISTICS 5.1.2 MINIMIZE IMPERVIOUS FOOTPRINT 7 5.1.3 CONSERVE NATURAL AREAS 7 5.1.4 MINIMIZE DIRECTLY CONNECTED IMPERVIOUS AREAS 8 5.1.5 MAXIMIZE CANOPY INTERCEPTION AND WATER CONSERVATION CONSISTENT WITH THE CARLSBAD LANDSCAPE MANUAL 8 5.1.6 CONVEY RUNOFF SAFELY FROM TOPS OF SLOPES 8 5.1.7 VEGETATE SLOPES WITH NATURAL OR DROUGHT TOLERANT VEGETATION 8 5.1.8 STABILIZE PERMANENT CHANNEL CROSSINGS 8 5.1.9 INSTALL ENERGY DISSIPATERS 9 5.2 SOURCE CONTROL BMPS 9 5.2.1 DESIGN OUTDOOR MATERIAL STORAGE AREAS TO REDUCE POLLUTION INTRODUCTION 9 5.2.2 DESIGN TRASH STORAGE ARES TO REDUCE POLLUTION INTRODUCTION 9 5.2.3 USE EFFICIENT IRRIGATION SYSTEMS AND LANDSCAPE DESIGN 10 5.2.4 PROVIDE STORM WATER CONVEYANCE SYSTEM STENCILING AND SIGNAGE 10 5.3 INDIVIDUAL PRIORITY PROJECT CATEGORIES 10 5.31 PRIVATE ROADS 10 5.3.2 RESIDENTIAL DRIVEWAYS AND GUEST PARKING 11 5.3.3 DOCK AREAS 11 5.3.4 MAINTENANCE BAYS 11 5.3.5 VEHICLE WASH AREAS 11 5.3.6 EQUIPMENT WASH AREAS 12 5.3.7 OUTDOOR PROCESSING AREAS 12 5.3.8 SURFACE PARKING AREAS 12 5.3.9 NON-RETAIL FUELING AREAS 13 5.3.10 HILLSIDE LANDSCAPING 13 5.4 TREATMENT CONTROL BMPS 13 5.4.1 TREATMENT CONTROL BMP DESIGN STANDARDS 13 Revised December 16, 2005 - Hi - 05-1117-5 August 3, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS TABLE OF CONTENTS (CONTINUED) ITEM PAGE 5.4.2 TREATMENT CONTROL BMP SELECTION 14 5.4.3 POLLUTANTS OF CONCERN 14 5.4.4 STRUCTURAL TREATMENT CONTROL BMP SELECTION 15 5.4.5 TREATMENT CONTROL BMP INFORMATION 15 5.4.5.1 POROUS PAVEMENT 15 5.4.5.2 INLINE FILTRATION 15 5.4.5.3 ADDITIONAL INFORMATION 16 5.4.6 STRUCTURAL TREATMENT LIMITED EXCLUSIONS.... 16 5.5 PERMANENT BMPS APPLICABLE TO THE PROJECT SITE 16 6.0 CONSTRUCTION STORM WATER BMPS 16 7.0 WATER POLLUTION CONTROL PLAN 16 7.1 SITE MANAGEMENT REQUIREMENTS 17 7.1.1 SELF-INSPECTIONS 17 7.1.2 SELF-INSPECTION PURPOSES 17 7.1.3 SELF-INSPECTION CHECKLIST 17 7.1.4 STORM WATER POLLUTION PREVENTION SITE MANAGEMENT REQUIREMENTS 18 7.2 PERFORMANCE STANDARDS 18 7.2.1 SITE INACTIVITY 18 7.2.2 STORM WATER CONVEYANCE SYSTEMS 19 7.3 SEASONAL REQUIREMENTS 19 7.3.1 DRY SEASON REQUIREMENTS 19 7.3.2 RAINY SEASON REQUIREMENTS 20 7.4 CONSTRUCTION BMPS 21 7.4.1 EROSION CONTROL BMPS 21 7.4.2 TEMPORARY SEDIMENT CONTROL BMPS 22 7.4.3 WIND EROSION BMPS 22 7.4.4 TEMPORARY TRACKING CONTROL BMPS 22 7.4.5 NON-STORMWATER MANAGEMENT BMPS 22 7.4.6 WASTE MANAGEMENT & MATERIALS POLLUTION CONTROL BMPS 23 7.5 CONSTRUCTION BMP CONCLUSION 23 8.0 IMPLEMENTATION & MAINTENANCE REQUIREMENTS 23 8.1 OPERATION AND MAINTENANCE PLAN 23 8.2 ACCESS EASEMENT/AGREEMENT 24 9.0 APPENDICES 24 APPENDIX A: VICINITY MAP «*«•>•• Revised December 16, 2005 - iv - 05-1117-5 August 3, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS TABLE OF CONTENTS (CONTINUED) ITEM PAGE APPENDIX A: VICINITY MAP APPENDIX B: STORM WATER REQUIREMENTS APPLICABILITY CHECKLIST APPENDIX C: CITY OF CARLSBAD STANDARDS EXCERPTS • TABLE 1: STANDARD DEVELOPMENT PROJECT & PRIORITY PROJECT STORM WATER BMP REQUIREMENTS MATRIX (PAGE 8) • TABLE 2: ANTICIPATED AND POTENTIAL POLLUTANTS GENERATED BY LAND USE TYPE (PAGE 12) • TABLE 3: NUMERIC SIZING TREATMENT STANDARDS (PAGE 20) • TABLE 4: STRUCTURAL TREATMENT CONTROL BMP SELECTION MATRIX (PAGE 21) • APPENDIX B: DRAFT ENVIRONMENTALLY SENSITIVE AREAS WITHIN THE CITY OF CARLSBAD MAP (PAGE 34) APPENDIX D: PRELIMINARY HYDROLOGY STUDY APPENDIX E: BENEFICIAL USES OF RECEIVING WATERS APPENDIX F: 2002 CWA SECTION 303(d) LOST OF WATER QUALITY LIMITED SEGMENTS APPENDIX G: SOURCE CONTROL BMP FACT SHEETS • CITY OF CARLSBAD GS-16: REFUSE BIN ENCLOSURES • CASQA SD-10: SITE DESIGN AND LANDSCAPE PLANNING • CASQA SD-11: ROOF RUNOFF CONTROLS • CASQA SD-12: EFFICIENT IRRIGATION • CASQA SD-13: STROM DRAIN STENCILING • CASQA SD-20: PERVIOUS PAVEMENT • CASQA SD-32: TRASH ENCLOSURES APPENDIX H: TREATMENT CONTROL BMP FACT SHEETS • CASQA MP-51: VORTEX SEPARATOR • CASQA TC-11: INFILTRATION BASIN • CASQA TC-60: MULTIPLE SYSTEM FACT SHEET • SECTION 6: LONG-TERM MAINTENANCE OF BMPS Revised December 16, 2005 - v - 05-1117-5 August 3, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS TABLE OF CONTENTS (CONTINUED) ITEM PAGE APPENDIX I: APPLICABLE MANUFACTURER'S BMP INFORMATION • KRISTAR DOWNSPOUT FILTER INFORMATION APPENDIX J: CASQA CONSTRUCTION BMP FACT SHEETS • EROSION CONTROL BMPS: 0 EC-1: SCHEDULING 0 EC-2: PRESERVATION OF EXISTING VEGETATION O EC-3: HYDRAULIC MULCH O EC-4: HYDROSEEDING 0 EC-5: SOIL BINDERS 0 EC-6: STRAW MULCH 0 EC-7: GEOTEXTILES AND MATS 0 EC-8: WOOD MULCHING 0 EC-9: EARTH DIKES AND DRAINAGE SWALES O EC-10: VELOCITY DISSIPATION DEVICES 0 EC-11: SLOPE DRAINS 0 EC-12: STREAMBANK STABILIZATION 0 EC-13: POLYACRYLAMIDE • TEMPORARY SEDIMENT CONTROL BMPS: 0 SE-1: SILT FENCE 0 SE-2: SEDIMENT BASIN O SE-3: SEDIMENT TRAP 0 SE-4: CHECK DAM 0 SE-5: FIBER ROLLS 0 SE-6: GRAVEL BAG BERM O SE-7: STREET SWEEPING AND VACUUMING O SE-8: SANDBAG BARRIER O SE-9: STRAW BALE BARRIER 0 SE-10: STROM DRAIN INLET PROTECTION • WIND EROSION BMPS: O WE-1: WIND EROSION CONTROL • TEMPORARY TRACKING CONTROL BMPS: O TC-1: STABILIZED CONSTRUCTION ENTRANCE/EXIT 0 TC-2: STABILIZED CONSTRUCTION ROADWAY O TC-3: ENTRANCE/OUTLET TIRE WASH Revised December 16, 2005 - vi - 05-1117-5 August 3, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS TABLE OF CONTENTS (CONTINUED) ITEM PAGE APPENDIX J: CASQA CONSTRUCTION BMP FACT SHEETS (CONTINUED) • NON-STORMWATER MANAGEMENT BMPS: O NS-1: WATER CONSERVATION PRACTICES O NS-2: DEWATER OPERATIONS 0 NS-3: PAVING AND GRINDING OPERATIONS 0 NS-4: TEMPORARY STREAM CROSSINGS O NS-5: CLEAR WATER DIVERSION O NS-6: ILLICIT CONNECTION/DISCHARGE O NS-7: POTABLE WATER/IRRIGATION 0 NS-8: VEHICLE AND EQUIPMENT CLEANING O NS-9: VEHICLE AND EQUIPMENT FUELING 0 NS-10: VEHICLE AND EQUIPMENT MAINTENANCE O NS-11: PILE DRIVING OPERATIONS O NS-12: CONCRETE CURING 0 NS-13: CONCRETE FINISHING O NS-14: MATERIAL AND EQUIPMENT USE O NS-15: DEMOLITION ADJACENT TO WATER 0 NS-16: TEMPORARY BATCH PLANTS • WASTE MANAGEMENT & MATERIALS POLLUTION CONTROL BMPS: O WM-1: MATERIAL DELIVERY AND STORAGE O WM-2: MATERIAL USE O WM-3: STOCKPILE MANAGEMENT 0 WM-4: SPILL PREVENTION AND CONTROL O WM-5: SOLID WASTE MANAGEMENT O WM-6: HAZARDOUS WASTE MANAGEMENT O WM-7: CONTAMINATED SOIL MANAGEMENT 0 WM-8: CONCRETE WASTE MANAGEMENT O WM-9: SANITARY/SEPTIC WASTE MANAGEMENT 0 WM-10: LIQUID WASTE MANAGEMENT APPENDIX K: MAP EXHIBITS • STATE STREET CONDOS PRELIMINARY STORM WATER MANAGEMENT PLAN POST CONSTRUCTION BMPS EXHIBIT Revised December 16,2005 -vii- 05-1117-5 August 3, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 1.0 INTRODUCTION '***" Federal, state and local agencies have established goals and objectives for storm water quality in the region. The proposed project is a priority project as defined in Order No. 2001-01 by the San Diego Region of the California Water Quality Control Board. As a result, the project is subject to SUSMP requirements. In addition, prior to the start of construction activities, the project will comply with all federal, state and local permits including the Stormwater Management Plan (SWMP) required under the County of San Diego Watershed Protection, Stormwater Management, and Discharge Control Ordinance (WPO) (section 67.871), the City of Carlsbad's Standard Urban Storm Water Mitigation Plan, and the National Pollution Discharge Elimination System (NPDES) from the Regional Water Quality Control Board (RWQCB). The purpose of this SWMP is to address the water quality impacts from the proposed improvements as shown on the Tentative Map. This project will provide guidelines in developing and implementing Best Management Practices (Best Management Practices) for storm water quality during construction and post construction. Since the site is less than 1 acre, a Storm Water Pollution Prevention Plan (SWPPP) will not be required. 1.1 PURPOSE This Standard Urban Storm Water Mitigation Plan (SUSWMP) is for the State Street Condos. It has been written to the standards set forth in the City of Carlsbad Engineering Standards, Volume 4: Stormwater Best Management Practices (BMPs) (2004 Edition). This report will reference these standards as »-* 'City Standards.' 1.2 LOCATION The State Street Condos are located according to the vicinity map found in Appendix A. 1.3 ABBREVIATIONS The following abbreviations will be utilized in this report: BMP = Best Management Practice City Standards = City of Carlsbad Engineering Standards SUSWMP = Standard Urban Storm Water Management Plan SWPPP = Storm Water Pollution Prevention Plan 2.0 PROJECT REVIEW & PERMITTING PROCESS In order to complete the Project Review & Permitting Process section of the City Standards the Storm Water requirements Applicability Checklist has been completed. For reference, this document has been included in Appendix B: Storm Water Requirements Applicability Checklist. Revised December 21,2005 -1- 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 2.1 DETERMINE APPLICABLE STORM WATER BMP REQUIREMENTS Based on the completed Storm Water Requirements Applicability Checklist completed for the State Street Condos (see Appendix B: Storm Water Requirements Applicability Checklist) the following requirements apply to the State Street Condos. 2.2 PRIORITY PROJECT PERMANENT STORM WATER BMP REQUIREMENTS Based on Section 1, Part A: Determine Priority Project Permanent Storm Water BMP Requirements of the Storm Water Requirements Applicability Checklist the following priority project categories apply to the State Street Condos: None apply Since the State Street Condos has no project categories that applicable from Section 1 of the Storm Water Requirements Applicability Checklist it will only be subject to Standard Permanent Storm Water BMP Requirements. Definitions for each of these items can be found in Appendix I: Definitions, of the City Standards. In addition, since the State Street Condos is only subject to standard permanent storm water requirements the design should incorporate all applicable requirements identified in Sections III.2 'Establish Permanent Storm Water Best Management Practices' (requirements 1 through 35) per the City Standards. This should include site design and source control BMPs; BMPs applicable to individual priority projects; and treatment control BMPs. Further guidance on these requirements can be found on page 7 of the City Standards. How this will be accomplished is discussed later in this report. 2.3 STANDARD PERMANENT STORM WATER BMP REQUIREMENTS Based on Section 1, Part B: Determine Standard Permanent Storm Water BMP Requirements of the Storm Water Requirements Applicability Checklist the following apply to the State Street Condos: • New impervious areas, such as rooftops, roads, parking lots, driveways, paths, and sidewalks • New pervious landscape areas and irrigation systems • Trash storage areas • Any grading or ground disturbance during construction • Any new storm drains, or alteration to existing storm drains Since the State Street Condos is subject to standard permanent storm water requirements only, the design should incorporate site design and source control requirements identified in Sections III.2.A and B (requirements 1 through 15) per Table 1 of the City Standards. How this will be accomplished is discussed later in this report. Revised December 21, 2005 - 2 - 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 2.4 CONSTRUCTION CRITERIA Based on Section 2, Part C: Determine Construction Phase Storm Water Requirements of the Storm Water Requirements Applicability Checklist the following apply to the State Street Condos: • The project proposes grading or soil disturbance • Storm water runoff or urban runoff has the potential to contact any portion of the construction area, including washing and staging areas • The project uses construction materials that could negatively affect water quality if discharged from the site (such as paints, solvents, concrete, and stucco) Since the State Street Condos is subject to construction storm water best management practices requirements the design should incorporate the standards set forth in Section IV, 'Construction Storm Water BMP Performance Standards,' of the City Standards, as applicable to the site. Further guidance on these requirements can be found on page 7 of the City Standards. How this will be accomplished is discussed later in this report. 2.5 CONSTRUCTION SITE PRIORITY Based on Section 2, Part D: Determine Construction Site Priority of the Storm Water Requirements Applicability Checklist the State Street Condos is classified as a Medium Priority Construction Site. 2.6 STORM WATER STANDARDS TABLE 1 Table 1 from page 8 of the City Standards has been included in Appendix C: City of Carlsbad Standards Excerpts for reference. 3.0 PREPARE AND SUBMIT APPROPRIATE PLANS Based on the general categories of storm water requirements that are applicable to the State Street Condos as described in section 2 above, the following categories from Table 1: Standard Development Project & Priority Project Storm Water BMP Requirements Matrix found on page 8 of the City Standards apply: 3.1 REQUIRED BMP ELEMENTS The following are required BMP elements for the State Street Condos and one or more applicable BMPs must be utilized: • Site Design BMPs • Source Control BMPs '"aw*"' Revised December 21,2005 -3- 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 3.2 OPTIONAL BMP ELEMENTS The following are optional best management practices, or BMPs that may be required by City of Carlsbad Staff for the State Street Condos: • Applicable to Individual Priority Projects o Private Roads o Residential Driveways & Guest Parking o Dock Areas o Maintenance Areas o Vehicle Wash Areas o Equipment Wash Areas o Outdoor Processing Areas o Surface Parking Areas o Fueling Areas o Hillside Landscaping • Treatment Control BMPs 3.3 TREATMENT CONTROL BMPS Because the State Street Condos is a priority project one or more Treatment Control BMPs will be required. 4.0 PERMANENT BEST MANAGEMENT PRACTICES SELECTION This section will identify what permanent best management practices will apply to the State Street Condos. 4.1 IDENTIFY POLLUTANTS FROM THE PROJECT AREA The State Street Condos does not fit into any particular category, but is best fit into the Attached Residential Development category. Based on the general pollutant categories and project categories as described in Table 2: Anticipated and Potential Pollutants Generated by Land Use Type found on page 12 of the City Standards the State Street Condos has the following pollutants: 4.1.1 ANTICIPATED POLLUTANTS OF CONCERN The following are anticipated pollutants of concern for the State Street Condos: • Sediment • Nutrients • Trash & Debris • Pesticides 4.1.2 POTENTIAL POLLUTANTS OF CONCERN The following are potential pollutants of concern for the State Street Condos: • Oxygen Demanding Substances • Oil & Grease • Bacteria & Viruses Revised December 21, 2005 - 4 - 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 4.2 IDENTIFY POLLUTANTS OF CONCERN IN RECEIVING WATERS This section will identify the pollutants or concern, if any, in the receiving waters of the State Street Condos proposed drainage pattern. 4.2.1 IDENTIFY THE HYDROLOGIC UNIT CONTRIBUTION The State Street Condos project is located in the Buena Vista Hydrologic Subarea (904.21) of the Carlsbad Hydrologic Unit in the San Diego Region. According to the City of Carlsbad's Standard Urban Storm Water Mitigation Plan, Appendix B: Draft Environmentally Sensitive Areas Within the City of Carlsbad Map (page 34, 4/3/2003 edition), the State Street Condos is not in an environmentally sensitive area. A copy of this map is provided in Appendix C. 4.2.2 IDENTIFY 303(d) IMPAIRMENTS IN THE RECEIVING WATERS In the 2002 CW Section 303(d) List of Water Quality Limited Segments, the Buena Vista Lagoon is impaired for bacteria indicators, nutrients, and sedimentation/siltation. Portions of Carlsbad where construction sites have the potential to discharge into a tributary of a 303 (d) or directly into a 303(d) water body or sites located within 200 feet of an ESA require additional BMP implementation. Since the Buena Vista Lagoon is one such receiving water, additional BMPs will be required. A copy of the 2002 CWA Section 303(d) List of Water Quality Limited Segments in included in Appendix F. 4.3 BENEFICIAL USES OF RECEIVING WATERS The beneficial uses for the hydrologic unit are included in Appendix E and a summary of the applicable definitions are listed below. This information comes from the Water Quality Control Plan for the San Diego Basin. 4.3.1 REC 1 - CONTACT RECREATION This beneficial use includes uses of water for recreational activities involving body contact with water, where ingestion of water is reasonably possible. These uses include, but are not limited to, swimming, wading, water-skiing, skin and SCUBA diving, surfing, white water activities, fishing, or use of natural hot springs. 4.3.2 REC 2 - NON-CONTACT RECREATION This beneficial use includes the uses of water for recreational activities involving proximity to water, but not normally involving body contact with water, where ingestion of water is reasonably possible. These include, but are not limited to, picnicking, sunbathing, hiking, camping, boating, tide pool and marine life study, hunting, sightseeing, or aesthetic enjoyment in conjunction with the above activities. Revised December21,2005 -5- 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 4.3.3 EST - ESTUARINE HABITAT ******' This beneficial use includes the uses of water that support estuarine ecosystems including, but not limited to, preservation or enhancement of estuarine habitats, vegetation, fish, or wildlife (e.g., estuarine mammals, waterfowl, shorebirds). 4.3.4 MAR - MARINE HABITAT This beneficial use includes uses of water that support marine ecosystems including, but not limited to, preservation or enhancement or marine habitats, vegetation such as kelp, fish, shellfish, or wildlife (e.g., marine mammals, shorebirds). 4.3.5 WILD - WILDLIFE HABITAT This beneficial use includes uses of water that support terrestrial ecosystems including but not limited to, preservation and enhancement of terrestrial habitats, vegetation, wildlife, (e.g., mammals, birds, reptiles, amphibians, invertebrates), or wildlife water food and sources. 4.3.6 RARE - RARE, THREATENED, OR ENDANGERED SPECIES This beneficial use includes uses of water that support habitats necessary, at least in part, for the survival and successful maintenance of plant or animal species established under state or federal law as rare, threatened or endangered. 4.4 IDENTIFY CONDITIONS OF CONCERN In order to determine if the State Street Condos proposed drainage patterns will effect the downstream conditions, a copy of the State Street Condos Preliminary Hydrology Study has been including in Appendix D: State Street Condos Preliminary Hydrology Study by O'Day Consultants, Inc dated December 21, 2005. According to this hydrology study the increase in discharge between the existing and proposed site development conditions is 0.0 cfs. 5.0 ESTABLISH PERMANENT STORM WATER BEST MANAGEMENT PRACTICES Because the State Street Condos is Standard Project, all the applicable BMPs will be applied to the project. Where applicable, the State Street Condos will incorporate storm water BMPs in the project design in the following progression: • Site Design BMPs • Source Control BMPs • Individual Project BMPs • Treatment Control BMPs Revised December 21, 2005 - 6 - 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 5.1 SITE DESIGN BMPS Site Design BMPs are comprised of the following BMPS: • Maintain Pre-Development Rainfall Runoff Characteristics o Minimize Impervious Footprint o Conserve Natural Areas o Minimize Directly Connected Impervious Areas o Maximize Canopy Interception and Water Conservation Consistent with the Carlsbad Landscape Manual • Protect Slopes and Channels o Convey Runoff Safely From Tops of Slopes o Vegetate Slopes with Natural or Drought Tolerant Vegetation o Stabilize Permanent Channel Crossings o Install Energy Dissipaters 5.1.1 MAINTAIN PRE-DEVELOPMENT RAINFALL RUNOFF CHARACTERISTICS This Site Design BMP entails controlling post construction peak storm water discharge at the rate and velocities of the pre-developed condition. Due to the fact that the residential density of the State Street Condos is increasing, this Site Design BMP cannot be utilized. 5.1.2 MINIMIZE IMPERVIOUS FOOTPRINT This Site Design BMP entails minimizing the proposed site impervious footprint through increasing building densities, utilizing impervious construction materials on walkways, driveways, trails, patios, overflow parking areas, alleys and low traffic areas. Examples of materials that can be used are pervious concrete, porous asphalt, unit pavers, and granular materials. In addition, streets, sidewalks, and parking lot aisles can be designed to minimum widths, provided pedestrian safety is not compromised. And lastly, this can be accomplished through the minimization of use of impervious surfaces, such as decorative concrete in landscape design. Based on the proposed site design of the State Street Condos minimizing the impervious footprint will be accomplished through the use of pervious concrete, minimum width sidewalks, and minimum width drive aisles. This will be accomplished through the use of CASQA BMP SD-20: Pervious Pavement. A copy of this is provided in Appendix G. 5.1.3 CONSERVE NATURAL AREAS This Site Design BMP entails concentrating or clustering development on the least environmentally sensitive portions of a site while leaving the reaming land in a natural, undisturbed condition and incorporates the use of natural drainage systems to the maximum extend practical. Since the State Street Condos existing condition is already developed, there are no natural areas to conserve; and as such, this Site Design BMP cannot be utilized. Revised December 21, 2005 - 7 - 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 5.1.4 MINIMIZE DIRECTLY CONNECTED IMPERVIOUS AREAS This Site Design BMP entails minimizing directly connect impervious areas where landscaping is proposed, where rooftops drain to adjacent landscaping areas, and where landscaping is proposed, attempt to direct runoff from impervious surfaces such as sidewalks, parking lots, walkways, trails, and patios to the landscaping areas. Based on the proposed site design of the State Street Condos minimizing the directly connected impervious areas will be accomplished by draining roof runoff through landscaping areas. This will be accomplished by utilizing roof drainage patterns in accordance with CASQA SD-11: Roof Runoff Control. A copy of this is provided in Appendix G. 5.1.5 MAXIMIZE CANOPY INTERCEPTION AND WATER CONSERVATION CONSISTENT WITH THE CARLSBAD LANDSCAPE MANUAL This Site Design BMP entails maximizing canopy interception and water conservation consistent with the Carlsbad Landscape Manual to preserve existing native trees and shrubs, to plant additional native or drought tolerant trees, and to plant large shrubs in place of non-drought tolerant exotic species. Based on the proposed site design of the State Street Condos this will be accomplished through a properly designed landscape plan that will be reviewed by the City of Carlsbad in order to verify that design in done in accordance with the Carlsbad Landscape Manual. 5.1.6 CONVEY RUNOFF SAFELY FROM TOPS OF SLOPES This Site Design BMP entails conveying runoff safely from the tops of slopes and in channels. Since the State Street Condos existing condition is already developed, there are no slopes; and as such, this Site Design BMP will not need to be utilized. 5.1.7 VEGETATE SLOPES WITH NATURAL OR DROUGHT TOLERANT VEGETATION This Site Design BMP entails the vegetation of slopes with native or drought tolerant vegetation where practically consistent with the Carlsbad Landscape Manual. Since the State Street Condos existing condition is already developed, there are no natural slopes to vegetate; and as such, this Site Design BMP will not need to be utilized. 5.1.8 STABILIZE PERMANENT CHANNEL CROSSINGS This site Design BMP entails the stabilization of permanent channel crossings. Since the State Street Condos existing condition is already developed, there are no channel crossings to stabilize; and as such, this Site Design BMP will not need to be utilized. Revised December 21, 2005 - 8 - 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 5.1.9 INSTALL ENERGY DISSIPATERS "**** This Site Design BMP entails installing energy dissipaters at the outlets of new storm drains, culverts, conduits, or channels that enter unlined channels. This is to be done in accordance with the applicable standards and specifications to minimize erosion. Energy dissipaters shall be installed in such a fashion as to minimize impacts to the receiving waters. Since the State Street Condos existing condition is already developed, there are is no need for energy dissipaters; and as such, this Site Design BMP will not need to be utilized. 5.2 SOURCE CONTROL BMPS Source Control BMPs are comprised of the following BMPS: • Design Outdoor Material Storage Areas to Reduce Pollution Introduction • Design Trash Storage Areas to Reduce Pollution Introduction • Use Efficient Irrigation Systems and Landscape Design • Provide Storm Water Conveyance System Stenciling and Signage 5.2.1 DESIGN OUTDOOR MATERIAL STORAGE AREAS TO REDUCE POLLUTION INTRODUCTION This Source Control BMP entails placing any and all potentially hazardous materials that have a potential to contaminate urban runoff in storage areas on site that are enclosed in structures such as, but not limited to, cabinets, ****"' sheds, or other similar structures that prevent and contain with rain, runoff, or spillage. In addition, secondary structures such as berms, dikes, or curbs will be utilized out side of the storage structure to further prevent contamination. The storage areas shall be paved with a sufficiently impervious material to contain leaks and spills, and shall have a roof or awning to minimize direct contact with precipitation within the secondary containment area. Since the State Street Condos are a residential development there will be no outdoor material storage areas; and as such, this Source Control BMP will not need to be utilized. 5.2.2 DESIGN TRASH STORAGE AREAS TO REDUCE POLLUTION INTRODUCTION This Source Control BMP entails designing trash storage areas to reduce pollution introduction. Trash Storage Areas shall be paved with an impervious surface, designed not to allow runoff from adjoining areas, screened or walled to prevent off-site transportation of trash, and contain attached lids on all trash containers that protects them from precipitation. Alternatively, the trash enclosure can contain a roof or awning to minimize direct contact with precipitation. The State Street Condos will be designing any trash storages areas to the design standards set forth in City of Carlsbad Engineering Standard Drawing GS-16 and in accordance with CASQA SD-32: Trash Enclosures. A copy of each of these is "****' provided in Appendix G. Revised December 21, 2005 - 9 - 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 5.2.3 USE EFFICIENT IRRIGATION SYSTEMS AND LANDSCAPE DESIGN This Source Control BMP entails employing rain shutoff devices to prevent irrigation during precipitation and requires all landscaping aspects to be designed per the Carlsbad Landscape Manual. The State Street Condos will accomplish this through the designing landscape tot eh Carlsbad Landscape Manual and the use of CASQA SD-10: Site Design and Landscape Planning and SD-12: Efficient Irrigation. A copy is provided in Appendix G. 5.2.4 PROVIDE STORM WATER CONVEYANCE SYSTEM STENCILING AND SIGNAGE This Source Control BMP entails providing storm drain conveyance system stenciling and signage. This shall be done by providing concrete stamping, porcelain tile, insert permanent marking or approved equivalent as approved by the City of Carlsbad, of all storm drain conveyance system inlets and catch basins within the project area with prohibitive language (i.e. "No Dumping - 1 Live Downstream') satisfactory to the City Engineer. In addition, signs shall be posted and prohibitive language and/or graphical icons, which prohibit illegal dumping at public access points along channels and creeks within the project area, trailheads, and parks shall be used. To accomplish this the State Street Condos will utilize CASQA SD-13: Strom Drain Stenciling. A copy of this is provided in Appendix G. 5.3 INDIVIDUAL PRIORITY PROJECT CATEGORIES Where identified in Table 1 of the City Standards, the following requirements shall be incorporated into priority projects: • Private Roads • Residential Driveways and Guest Parking • Dock Areas • Maintenance Bays • Vehicle Wash Areas • Equipment Wash Areas • Outdoor Processing Areas • Surface Parking Areas • Non-Retail Fueling Areas • Hillside Landscaping 5.3.1 PRIVATE ROADS The design of private roadway drainage shall incorporate, the extent possible and practical, rural swale systems, urban curb and gutter, dual drainage systems, and other treatment control BMPs as approved by the City Engineer. Since the State Street Condos are a residential redevelopment there will be no private roads being proposed; and as such, this Individual Priority Project BMP will not need to be utilized. Revised December 21, 2005 - 10 - 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 5.3.2 RESIDENTIAL DRIVEWAYS AND GUEST PARKING Residential driveways shall have, to the extent practical, shared access, flared entrances (single lane at street), wheel strips (paving only under tires), and be designed to drain to landscaped areas prior to discharging to the storm water conveyance system. Since the State Street Condos are a residential redevelopment there is no feasible way to incorporate this Individual Priority Project BMP into the site design. 5.3.3 DOCK AREAS Dock areas, or loading and unloading areas, shall include the following elements: covered loading dock areas or be designed to preclude urban run-on and runoff; and be prohibited from directly connecting to storm drain conveyance systems from depressed loading decks (truck wells). Since the State Street Condos are a residential redevelopment there are no dock areas being proposed; and as such, this Individual Priority Project BMP will not need to be utilized. 5.3.4 MAINTENANCE BAYS Maintenance bays shall be designed to be indoors or to preclude urban run-on and runoff. In addition, maintenance/repair bays shall include a separate system to capture all wash water, leaks and spills. Connect all drains to a sump for collection and disposal. Direct connection of the maintenance or repair bays to the storm water conveyance system is prohibited. Where areas are allowed to connect to the sanitary sewer system, an Industrial Waster Permit from the Encina Water Pollution Control Facility may be required. Since the State Street Condos are a residential redevelopment there are no maintenance bays being proposed; and as such, this Individual Priority Project BMP will not need to be utilized. 5.3.5 VEHICLE WASH AREAS Vehicle wash areas shall be self-contained to preclude run-on and runoff, covered with a roof or overhang, and be equipped with a clarifier or other pre-treatment facility. In addition vehicle wash areas shall be properly connected to a sanitary sewer if appropriate. Where areas are connected to a sanitary sewer and Industrial Waste Permit may be required from the Encina Water Pollution Control Facility. Since the State Street Condos are a residential redevelopment there are no vehicle wash areas being proposed; and as such, this Individual Priority Project BMP will not need to be utilized. Revised December 21,2005 -11 - 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 5.3.6 EQUIPMENT WASH AREAS Equipment wash areas shall be self-contained to preclude run-on and runoff, covered with a roof or overhang, and be equipped with a clarifier or other pre-treatment facility. In addition Equipment wash areas shall be properly connected to a sanitary sewer if appropriate. Where areas are connected to a sanitary sewer and Industrial Waste Permit may be required from the Encina Water Pollution Control Facility. Since the State Street Condos are a residential redevelopment there are no equipment wash areas being proposed; and as such, this Individual Priority Project BMP will not need to be utilized. 5.3.7 OUTDOOR PROCESSING AREAS Outdoor processing areas shall cover or enclose areas that are the most significant source of pollutants or slope the area toward a dead-end sump or discharge the area to the sanitary sewer system. Where areas are connected to a sanitary sewer and Industrial Waste Permit may be required from the Encina Water Pollution Control Facility. In addition, the processing area must be graded or contain berms to prevent run-on from surrounding areas. Installation of storm drains in areas of equipment repair is prohibited. Since the State Street Condos are a residential redevelopment there are no outdoor processing areas being proposed; and as such, this Individual Priority Project BMP will not need to be utilized. 5.3.8 SURFACE PARKING AREAS Surface parking areas (covered and uncovered) where landscaping is proposed shall incorporate the landscape areas into the drainage design. Parking that is in excess of the project's minimum requirements (overflow parking) may be constructed with permeable paving subject to the City Engineer's approval. The State Street Condos will be utilizing CASQA SD-20: Pervious Pavement for all parking areas. A copy of this is provided in Appendix G. Revised December 21, 2005 -12 - 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 5.3.9 NON-RETAIL FUELING AREAS Non-Retail fueling areas shall be paved with Portland cement or approved equivalent, smooth impervious surface. Asphalt concrete paving is prohibited. Shall be designed to extend 6.5 feet from the center of each fuel dispenser, or the length at which the hose and nozzle assembly may be operated plus one foot, whichever is greater. Shall be sloped to prevent ponding. Shall be separated from the rest of the site by a grade break that prevents run-on of urban runoff. And shall drain to the project's treatment control BMP prior to discharging to the storm water conveyance system. In addition, overhanging roof structures or canopies that are equal to or greater then the area within the fuel dispensing area's grade break and that are designed not to drain onto or across fuel dispensing areas are also required. Since the State Street Condos are a residential redevelopment there are no non-retail fueling areas being proposed; and as such, this Individual Priority Project BMP will not need to be utilized. 5.3.10 HILLSIDE LANDSCAPING Hillside landscaping areas disturbed by the project development shall be landscaped with deep-rooted, drought tolerant plant species selected for erosion control properties and shall be done so in accordance with the Carlsbad Landscape Manual. Since the State Street Condos are a residential redevelopment of an existing development there is no hillside landscaping required or being proposed; and as such, this Individual Priority Project BMP will not need to be utilized. 5.4 TREATMENT CONTROL BMPS Where identified in Table 1 of the City Standards, and after site design and source control BMPs have been incorporated into the project design, treatment control BMPs may then be utilized. 5.4.1 TREATMENT CONTROL BMP DESIGN STANDARDS Treatment Control BMPs shall be designed to infiltrate, filter, and/or treat runoff from the project footprint to per Table 3: Numeric Sizing Treatment Standards. A copy of Table 3 is provided in Appendix C. There are four guidelines that need to be followed for Treatment Control BMPs: • All Structural Treatment Control BMPs shall infiltrate, filter, and/or treat the required runoff volume or flow prior to discharging to any receiving water body supporting beneficial uses. • Multiple post construction Structural Treatment Control BMPs for a single priority project shall collectively be designed to comply with the numeric sizing treatment standards. • Shared BMPs shall be operational prior to the use of any dependent development or phase of development. The shared BMPs shall only be required to treat the dependent developments or phases of development that are in use. Revised December 21, 2005 -13 - 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS • Interim storm water BMPs that provide equivalent or greater treatment than is required may be implemented by a dependant development until each shared BMP is operational. If interim BMPs are selected, the BMPs shall remain in use until permanent BMPs are operational. 5.4.2 TREATMENT CONTROL BMP SELECTION All projects classified as Priority Projects in the City of Carlsbad shall select a single or combination of treatment control BMPs from the categories listed in Table 4: Structural Treatment Control BMPs Selection Matrix. A copy of Table 4 is provided in Appendix C. This selection matrix will determine the most efficient removal BMP for the pollutants of concern from the project site. The most efficient device or combination of devices shall be utilized to maximize pollutant removal. 5.4.3 POLLUTANTS OF CONCERN Based on the above findings for the proposed site usage the State Street Condos has the following pollutants of concern: • Sediment (Anticipated) • Nutrients (Anticipated) • Trash & Debris (Anticipated) • Oxygen Demanding Substances (Potential by use) • Bacteria (Potential by use) • Oil & Grease (Potential by use) • Pesticides (Anticipated) Based on the actual design of the State Street Condos the following is the applicable pollutants of concern: • Sediment (Anticipated) • Nutrients (Anticipated) • Trash & Debris (Anticipated) • Oxygen Demanding Substances (Potential) • Bacteria (Potential) • Oil & Grease (Potential) • Pesticides (Anticipated) Revised December 21, 2005 -14 - 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 5.4.4 STRUCTURAL TREATMENT CONTROL BMP SELECTION Based on the pollutants of concern present from the project site and the removal efficiencies listed in Table 4: Structural Treatment Control BMP Selection Matrix, the Structural Treatment Control BMP with the most efficient removal efficiencies for the State Street Condos are as follows (listed most to least efficient): • Filtration • Detention Basins • Infiltration Basins • Wet Ponds or Wetlands • Hydrodynamic Separator Systems • Biofilters • Drainage Inserts Based on these removal efficiencies, the State Street Condos shall utilize In-Line filtration for roof runoff before it is placed into landscaped areas and shall use infiltration via pervious pavement in the parking areas. The reason that these were chosen instead of a strict filtration or detention basin system is that the State Street Condos are a redevelopment or an existing apartment style site and there is not enough land to efficiently, practically, or feasibly utilize those BMPs. 5.4.5 TREATMENT CONTROL BMP INFORMATION Two treatment control devices will be utilized on the State Street Condo project site. They are porous pavement and inline filtration. 5.4.5.1 POROUS PAVEMENT The first treatment control BMP that will be utilized on the State Street Condos is porous pavement. This will be done in accordance with CASQA SD-20: Pervious Pavement. A copy of this is provided in Appendix G. In addition, the porous pavement will also be done per CASQA TC-11: Infiltration Basin. A copy of this is provided in Appendix H. 5.4.5.2 INLINE FILTRATION The second treatment control device what will be utilized on the State Street Condos is inline Filtration. This will treat the roof runoff before it is discharged into the landscaped areas. The product that is being recommended is a Kristar Downspout Filter. They are designed to be installed in the wall and connected to the roof drains prior to the discharge point. Product information for this device is provided in Appendix I. This device is classified as a gravity vortex separator and will also be implemented with CASQA MP-51: Vortex Separator in mind as well. A copy of this is provided in Appendix H. Revised December 21, 2005 -15 - 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 5.4.5.3 ADDITIONAL INFORMATION In addition, the selected devices will also be implemented with CASQA TC-60: Multiple System Fact Sheet in mind. A copy of this is provided in Appendix H. Also, since long term maintenance is an integral part of any post construction BMP plan, CASQA Section 6: Long-Term Maintenance of BMPs will also be implemented on the State Street Condos. A copy is provided in Appendix H. 5.4.6 STRUCTURAL TREATMENT LIMITED EXCLUSIONS No Structural Treatment Limited Exclusions apply to this project as defined in the City Standards. 5.5 PERMANENT BMPS APPLICABLE TO THE PROJECT SITE Based on the above findings, the following permanent BMPs will be established for the State Street Condos: Site Design BMPs: • Minimize Impervious Footprint • Minimize Directly Connected Impervious Areas • Maximize Canopy Interception and Water Conservation Consistent with the Carlsbad Landscape Manual Source Control BMPs: • Design Trash Storage Areas to Reduce Pollution Introduction • Use Efficient Irrigation Systems and Landscape Design • Provide Storm Water Conveyance System Stenciling and Signage Applicable to Individual Priority Projects • Surface Parking Areas Treatment Control BMPs: • Inline Roof Filtration • Porous Pavement 6.0 CONSTRUCTION STORM WATER BMPS Since the State Street Condos has a disturbed area of 0.28 acres a Water Pollution Control Plan will be required by the City of Carlsbad. Construction BMPs and any applicable design standards for the Water Pollution Control Plan can be found in Section 7.0 of this report. 7.0 WATER POLLUTION CONTROL PLAN Based on the size of the State Street Condos being 0.28 acres this section of this report has been created to satisfy City Standard Section IV: Construction Storm Water Performance Standards. Revised December 21, 2005 -16 - 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 7.1 SITE MANAGEMENT REQUIREMENTS Construction of the State Street Condos will be a dynamic process and daily construction practices are expected to change as well. Construction BMP usage ranges from everyday use to ones that are only needed when a particular activity is in use. Therefore, the City of Carlsbad requires owner/contractor self- inspections. 7.1.1 SELF-INSPECTIONS Self-inspection shall be performed by the owner's/contractor's Qualified Contact Person. This person shall be specially trained in SWPPP site management and storm water BMPs, including installation and maintenance of sediment and erosion control measures. This person is required to be onsite during both the wet and dry seasons. 7.1.2 SELF-INSPECTION PURPOSES There are four primary purposes for self-inspections. They are as follows: • To ensure that the owners/contractors take full responsibility for managing storm water pollution caused by their construction activities. • To ensure that storm water BMPs are properly documented and implemented and are functioning effectively. • To identify maintenance (i.e. sediment removal) and repair needs • To ensure that the project proponents implement their storm water management plans. 7.1.3 SELF-INSPECTION CHECKLIST A self-inspection checklist, noting date, time, conditions, and inspection date, at a minimum, must be kept on site and made available for inspection, if requested by applicable agencies. Self-inspections must be performed by a Qualified Contact Person according to the following schedule: • Daily weather forecasting at all times • At 24-hour intervals during extended rainfall events • Daily evaluations as earth moving/grading is being conducted during the wet season • Weekly (every 7 days) in the dry season as earth moving/grading is progressing • Self-inspection checklists shall be submitted to the project inspector on a weekly basis during the rainy season Revised December 21, 2005 -17 - 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 7.1.4 STORM WATER POLLUTION PREVENTION SITE MANAGEMENT REQUIREMENTS Storm water pollution prevention site management requirements include, but are not limited to the following items: • A qualified person who is trained and competent in the use of BMPs shall be on site daily, although not necessarily full time, to evaluate the conditions of the site with respect to storm water pollution prevention. This qualified contact person shall represent the owner/contractor on storm water issues. • The qualified person shall implement the conditions of the Storm Water Pollution Prevention Plan, contract documents, and/or local ordinances with respect to erosion and sediment control and other water management regulations. • The qualified person is responsible for monitoring the weather and implementation of any emergency plans as needed. The weather shall be monitored on a 5-day forecast plan and a full BMP protection plan shall be activated when there is a 40% chance (or greater) of rain. • The qualified person is responsible for overseeing any site grading and operations and evaluating the effectiveness of BMPs. This person shall modify the BMPs as necessary to keep the dynamics of the site in compliance. This person or other qualified persons are responsible for checking the BMPs routinely for maintenance and documenting the BMPs being implemented. 7.2 PERFORMANCE STANDARDS The City of Carlsbad shall evaluate the adequacy of the owner's/contractor's site management for storm water pollution prevention, inclusive of BMP implementation, on construction sites based on performance standards for storm water BMPs. Poor BMP practices shall be challenged. Performance standards shall include, but are not limited to the following: • Prevent increase in pollution to the maximum extend practical • Minimize slope erosion • Control discharge velocities moving offsite to limit down stream erosion potential to the pre-construction levels 7.2.1 SITE INACTIVITY A construction site shall be considered inactive if construction activities have ceased for a period of seven (7) or more consecutive calendar days. At any time of year, an inactive site must be fully protected from erosion and sediment discharge. It is also the owner's/contractor's responsibility at both active and inactive construction sites to implement a plan to address all potential non-storm water discharges. Revised December 21, 2005 -18 - 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 7.2.2 STORM WATER CONVEYANCE SYSTEMS Regardless of any inspections conducted by the City of Carlsbad, the property owners or contractors are required to prevent any construction related materials, like trash, wastes, spills, residues, etc. from entering the storm water conveyance system. 7.3 SEASONAL REQUIREMENTS There are different requirements based on the season. 7.3.1 DRY SEASON REQUIREMENTS The dry season is May 1 through September 30. The following requirements apply during the dry season: 1. Perimeter protection BMPs must be installed and maintained to comply with performance standards (above). 2. Sediment control BMPs must be installed and maintained to comply with performance standards (above). 3. BMPs to control sediment tracking must be installed and maintained at all entrances and exits to comply with performance standards (above). 4. Material needed to install standby BMPs necessary to completely protect the exposed portions of the site from erosion, and to prevent sediment discharges, must be stored on site areas that have already been protected from erosion using physical stabilization or established vegetation stabilization BMPs as described below are not considered to be 'exposed' for purposes of this requirement. 5. The owner/contractor must have an approved 'weather triggered' action plan and have the ability to deploy standby BMPs as needed to completely protect the exposed portions of the site within 24 hours of prediction of a storm event (a predicted storm event is defined as a forecasted 40% chance of rain). On request, the owner/contractor must provide proof of this capability that is acceptable to the City of Carlsbad. 6. Deployment of physical or vegetation erosion control BMPs must commence as soon as grading and/or excavation is completed for any portion of the site. The project proponents may not continue to rely on the ability to deploy standby BMP materials to prevent erosion of graded areas that have been completed. 7. The area that can be cleared and graded and left exposed at one time is limited to the amount of acreage that the owner/contractor can adequately protect prior to a predicted rainstorm. This may require grading to be phased at larger sites. For example, it may be necessary to deploy erosion and sediment control BMPs in areas that are not actively being worked before additional grading is done. Revised December 21, 2005 -19 - 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 7.3.2 RAINY SEASON REQUIREMENTS The rainy season is October 1 through April 30. The following requirements apply during the rainy season: 1. Perimeter protection BMPs must be installed and maintained to comply with performance standards (above). 2. Sediment control BMPs must be installed and maintained to comply with performance standards (above). 3. BMPs to control sediment tracking must be installed and maintained at all entrances and exits to comply with performance standards (above). 4. Material needed to install standby BMPs necessary to completely protect the exposed portions of the site from erosion, and to prevent sediment discharges, must be stored on site areas that have already been protected from erosion using physical stabilization or established vegetation stabilization BMPs as described below are not considered to be 'exposed' for purposes of this requirement. 5. The owner/contractor must have an approved 'weather triggered' action plan and have the ability to deploy standby BMPs as needed to completely protect the exposed portions of the site within 24 hours of prediction of a storm event (a predicted storm event is defined as a forecasted 40% chance of rain). On request, the owner/contractor must provide proof of this capability that is acceptable to the City of Carlsbad. 6. Deployment of physical or vegetation erosion control BMPs must commence as soon as grading and/or excavation is completed for any portion of the site. The project proponents may not continue to rely on the ability to deploy standby BMP materials to prevent erosion of graded areas that have been completed. 7. The area that can be cleared and graded and left exposed at one time is limited to the amount of acreage that the owner/contractor can adequately protect prior to a predicted rainstorm. This may require grading to be phased at larger sites. For example, it may be necessary to deploy erosion and sediment control BMPs in areas that are not actively being worked before additional grading is done. 8. Erosion control BMPs must be upgraded, if necessary, to provide sufficient protection for storms likely to occur during the rainy season. 9. Perimeter protection and sediment control BMPs must be upgraded, if necessary, to provide sufficient protection for storms likely to occur during the rainy season. Revised December 21, 2005 - 20 - 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 10. Adequate physical or vegetation erosion control BMPs must be ****' installed and established for graded areas prior to the start of the rainy season. These BMPs must be maintained throughout the rainy season. If a selected BMP fails, it must be repaired and improved, or replaced with an acceptable alternative as soon as it is safe to do so. The failure of a BMP shows that the BMP, as installed, was not adequate for the circumstances in which it was used and shall be corrected or modified as necessary. Repairs or replacements must therefore put a more effective BMP in place. 11. All vegetation erosion control must be established prior to the rainy season to be considered as a BMP. 7.4 CONSTRUCTION BMPS The following are BMPs that should be used during construction. This is not an exclusive list of all possible Construction BMPs, but rather a start to what is required of a construction site. Not all of the listed construction BMPs may be required on the project site but are included here as a reference. All BMPs are the responsibility of the owner/contractor to implement properly. In addition, all Construction BMPs are subject to City of Carlsbad review and acceptance. Copies of all BMPs listed here are also provided in Appendix J. 7.4.1 EROSION CONTROL BMPS The following are CASQA Construction Erosion Control BMPs: • EC-1: Scheduling • EC-2: Preservation of Existing Vegetation • EC-3: Hydraulic Mulch • EC-4: Hydroseeding • EC-5: Soil Binders • EC-6: Straw Mulch • EC-7: Geotextiles and Mats • EC-8: Wood Mulching • EC-9: Earth Dikes and Drainage Swales • EC-10: Velocity Dissipation Devices • EC-11: Slope Drains • EC-12: Streambank Stabilization • EC-13: Polyacrylamide Revised December 21,2005 -21 - 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 7.4.2 TEMPORARY SEDIMENT CONTROL BMPS *•*«" The following are CASQA Construction Temporary Sediment Control BMPs: • SE-1: Silt Fence • SE-2: Sediment Basin • SE-3: Sediment Trap • SE-4: Check Dam • SE-5: Fiber Rolls • SE-6: Gravel Bag Berm • SE-7: Street Sweeping and Vacuuming • SE-8: Sandbag Barrier • SE-9: Straw Bale Barrier • SE-10: Strom Drain Inlet Protection 7.4.3 WIND EROSION BMPS The following are CASQA Construction Wind Erosion BMPs: • WE-1: Wind Erosion Control 7.4.4 TEMPORARY TRACKING CONTROL BMPS The following are CASQA Construction Temporary Tracking Control BMPs: • TC-1: Stabilized Construction Entrance/Exit • TC-2: Stabilized Construction Roadway *"" • TC-3: Entrance/Outlet Tire Wash 7.4.5 NON-STORMWATER MANAGEMENT BMPS The following are CASQA Construction Non-Stormwater Management BMPs: • NS-1: Water Conservation Practices • NS-2: Dewater Operations • NS-3: Paving and Grinding Operations • NS-4: Temporary Stream Crossings • NS-5: Clear Water Diversion • NS-6: Illicit Connection/Discharge • NS-7: Potable Water/Irrigation • NS-8: Vehicle and Equipment Cleaning • NS-9: Vehicle and Equipment Fueling • NS-10: Vehicle and Equipment Maintenance • NS-11: Pile Driving Operations • NS-12: Concrete Curing • NS-13: Concrete Finishing • NS-14: Material and Equipment Use • NS-15: Demolition Adjacent to Water • NS -16: Temporary B atch Plants Revised December 21, 2005 - 22 - 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 7.4.6 WASTE MANAGEMENT & MATERIALS POLLUTION •^ CONTROL BMPS The following are CASQA Construction Waste Management & Materials Pollution Control BMPs: • WM-1: Material Delivery and Storage • WM-2: Material Use • WM-3: Stockpile Management • WM-4: Spill Prevention and Control • WM-5: Solid Waste Management • WM-6: Hazardous Waste Management • WM-7: Contaminated Soil Management • WM-8: Concrete Waste Management • WM-9: Sanitary/Septic Waste Management • WM-10: Liquid Waste Management 7.5 CONSTRUCTION BMP CONCLUSION Although this report lists a multitude of Construction BMPs to be utilized, it is also to be noted that these are just guidelines. The Owner's/Contractor's Qualified Contact Person will be responsible for implementing an effective storm water management plan to the satisfaction of the City of Carlsbad Inspector. 8.0 IMPLEMENTATION & MAINTENANCE REQUIREMENTS Once the City of Carlsbad approves all the State Street Condos BMPs, the applicants and "***' the City Project Managers must ensure proper implementation of the selected BMPs. In order to accomplish effective implementation and maintenance the City of Carlsbad may require that some sort of Permanent BMP Maintenance Agreement be entered into. This will be at the discretion of the City of Carlsbad Staff. In the event that a Permanent BMP Maintenance Agreement is required by City Staff, the following items will need to be addressed: 8.1 OPERATION AND MAINTENANCE PLAN The applicant shall include and Operation & Maintenance Plan (O&M), prepared satisfactory to the City, with the approved maintenance agreement, which describes the designated responsible party to mange the storm water BMPs, employee's training program and duties, operating schedule, maintenance frequency, routine service schedule, specific maintenance activities (including maintenance of storm water conveyance system stamps), copies of resource agency permits, and any other necessary activities. At a minimum, maintenance agreements shall require the applicant to provide inspection and servicing of all permanent treatment BMPs on an annual basis. The project proponent or City- approved maintenance entity shall complete and maintain O&M forms to document all maintenance requirements. Parties responsible for the O&M plan shall retain records for at least 5 years. These documents shall be made available to the City inspector upon request at any time. Revised December 21,2005 -23- 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS 8.2 ACCESS EASEMENT/AGREEMENT If a permanent BMP requires access for maintenance, as part of the O&M plan, the applicant shall execute and record an access easement or agreement that shall be binding on the under lying land throughout the life of the project in favor of the party responsible for maintenance, until such time that the permanent treatment BMP requiring access for maintenance is removed or replaced. The City shall approve any changes to the permanent BMPs, O&M plans, or access agreements. The agreement shall include a provision that gives the City the right, but not the obligation to perform the maintenance. The party responsible for BMP maintenance will pay the City for any and all costs uncured by the City for maintaining any BMPs. The agreement will provide a cost recovery provision in favor of the City satisfactory to the City Attorney. 9.0 APPENDICES: The following Appendices are included: Appendix A: Vicinity Map Appendix B: Storm Water Requirement Applicability Checklist Appendix C: City of Carlsbad Standards Excerpts • Table 1: Standard Development Project & Priority Project Storm Water BMP Requirements Matrix (page 8) • Table 2: Anticipated and Potential Pollutants Generated by Land Use Type (page 12) • Table 3: Numeric Sizing Treatment Standards (page 20) • Table 4: Structural Treatment Control BMP Selection Matrix (page 21) • Appendix B: Draft Environmentally Sensitive Areas Within the City of Carlsbad Map (page 34) Appendix D: Preliminary Hydrology Study Preliminary Hydrology Study for State Street Condos by O'Day Consultants, Inc. dated December 21, 2005 Appendix E: Beneficial Uses of Receiving Waters Appendix F: 2002 CWA Section 303(d) List of Water Quality Limited Segments Revised December 21, 2005 - 24 - 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS Appendix G: Source Control BMP Fact Sheets Carlsbad Standard Drawing GS-16: Refuse Bin Enclosures CASQA SD-10: Site Design and Landscape Planning CASQA SD-11: Roof Runoff Controls CASQA SD-12: Efficient Irrigation CASQA SD-13: Strom Drain Stenciling CASQA SD-20: Pervious Pavement CASQA SD-32: Trash Enclosures Appendix H: Treatment Control BMP Fact Sheets CASQA MP-51: Vortex Separator CASQA TC-11: Infiltration Basin CASQA TC-60: Multiple System Fact Sheet Section 6: Long-term Maintenance of BMPs Appendix I: Applicable Manufacturer's BMP Information Kristar Downspout Filter Information Appendix J: CASQA Construction BMP Fact Sheets Erosion Control BMPs: • EC-1: Scheduling • EC-2: Preservation of Existing Vegetation • EC-3: Hydraulic Mulch • EC-4: Hydroseeding • EC-5: Soil Binders • EC-6: Straw Mulch • EC-7: Geotextiles and Mats • EC-8: Wood Mulching • EC-9: Earth Dikes and Drainage Swales • EC-10: Velocity Dissipation Devices • EC-11: Slope Drains • EC-12: Streambank Stabilization • EC-13: Polyacrylamide Temporary Sediment Control BMPs: • SE-1: Silt Fence • SE-2: Sediment Basin • SE-3: Sediment Trap • SE-4: Check Dam • SE-5: Fiber Rolls • SE-6: Gravel Bag Berm • SE-7: Street Sweeping and Vacuuming • SE-8: Sandbag Barrier • SE-9: Straw Bale Barrier • SE-10: Strom Drain Inlet Protection Revised December 21, 2005 - 25 - 05-1117-5 August 4, 2005 PRELIMINARY STANDARD URBAN STORM WATER MANAGEMENT PLAN STATE STREET CONDOS Wind Erosion BMPs: • WE- 1 : Wind Erosion Control Temporary Tracking Control BMPs: • TC-1: Stabilized Construction Entrance/Exit • TC-2: Stabilized Construction Roadway • TC-3 : Entrance/Outlet Tire Wash Non-Stormwater Management BMPs: • NS-1: Water Conservation Practices • NS-2: Dewater Operations • NS-3: Paving and Grinding Operations • NS-4: Temporary Stream Crossings • NS-5: Clear Water Diversion • NS-6: Illicit Connection/Discharge • NS-7: Potable Water/Irrigation • NS-8: Vehicle and Equipment Cleaning • NS-9: Vehicle and Equipment Fueling • NS-10: Vehicle and Equipment Maintenance • NS- 1 1 : Pile Driving Operations • NS-1 2: Concrete Curing • NS-13: Concrete Finishing • NS-14: Material and Equipment Use • NS - 1 5 : Demolition Adj acent to Water • NS- 16: Temporary Batch Plants Waste Management & Materials Pollution Control BMPs: • WM-1: Material Delivery and Storage • WM-2: Material Use • WM-3: Stockpile Management • WM-4: Spill Prevention and Control • WM-5: Solid Waste Management • WM-6: Hazardous Waste Management • WM-7: Contaminated Soil Management • WM-8: Concrete Waste Management • WM-9: Sanitary/Septic Waste Management • WM-10: Liquid Waste Management Appendix K: Map Exhibits • State Street Condos Preliminary Storm Water Management Plan Post Construction BMPs Exhibit Revised December 21,2005 -26- 05-1117-5 August 4, 2005 APPENDIX A APPENDIX A: VICINITY MAP CITY OF OCEANSIDE HIGHWAYu i CITY OF VISTA CITY OF SAN MARCOS VICINITY MAP NO SCALE APPENDIX B APPENDIX B STATE STREET CONDOS STORM WATER REQUIREMENTS APPLICABILITY CHECKLIST CITY OF CARLSBAD STORM WATER STANDARDS APPENDIX A: STORM WATER REQUIREMENTS APPLICABILITY CHECKLIST This summary is designed as a quick reference for Appendix A: Storm Water Requirements Applicability Checklist from the City of Carlsbad Public Works Department Standard Urban Storm Water Mitigation Plan Storm Water Standards (April 2003, page 30). PART A: DETERMINE PRIORITY PROJECT PERMANENT STORM WATER BMP REQUIREMENTS Part A: Determine Priority Project Permanent Storm Water BMP Requirements Does the project meet the definition of one or more of the priority project categories?* 1. 2. 3. 4. 5. 6. 7. 8. 9. Detached residential development of 10 or more units Attached residential development of 10 or more units Commercial development greater than 100,000 square feet Automotive repair shop Restaurant Steep hillside development greater than 5,000 square feet Project discharging to receiving water within Environmentally Sensitive Areas Parking lots greater than or equal to 5,000 square feet or with at least 15 parking spaces, and potentially exposed to urban runoff Streets, roads, and freeways which would create a new paved surface that is 5,000 square feet of greater Yes No X X X X X X X X X * Refer to the definitions section in the Storm Water Standards for expanded definitions of the priority project categories. Limited Exclusions: Trenching and resurfacing work associated with utility projects are not considered priority projects. Parking lots, buildings and other structures associated with utility projects are priority projects if one or more of the criteria in Part A is met. If all answers to Part A are 'No,' continue to Part B. APPENDIX B STATE STREET CONDOS STORM WATER REQUIREMENTS APPLICABILITY CHECKLIST PART B: DETERMINE STANDARD PERMANENT STORM WATER BMP REQUIREMENTS Part B: Determine Standard Permanent Storm Water BMP Requirements Does the project Propose: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. *To Disc wwv New impervious areas, such as rooftops, roads, parking lots, driveways, paths and sidewalks? New pervious landscape areas and irrigation systems? Permanent structures within 100 feet of any natural water body? Trash storage areas? Liquid or solid material loading and unloading areas? Vehicle or equipment fueling, washing, or maintenance areas? Require a General NPDES Permit for Storm Water Discharges Associated with Industrial Activities (except construction)?* Commercial or Industrial waste handling or storage, excluding typical office or household waste? Any grading or ground disturbance during construction? Any new storm drains, or alterations to existing storm drains? find out if your project is required to obtain individual General NPDES Permit for i harges Associated with Industrial Activities, visit the State Water Resources Contro y.swrcb.ca.£ov/stormwtr/industrial.html Yes X X X X X No X X X X X strom Water Board website at PART C: DETERMINE CONSTRUCTION STORM WATER BMP REQUIREMENTS Part C: Determine Construction Storm Water BMP Requirements Would the project meet any of these criteria during construction? 1. 2. 3. 4. Is the project subject to California's statewide General NPDES Permit for Storm Water Discharges Associated with Construction Activities? Does the project propose grading or soil disturbance? Would storm water or urban runoff have the potential to contact any portion of the construction area, including washing and staging areas? Would the project use any construction materials that could negatively affect water quality if discharged from the site (such as paints, solvents, concrete, and stucco)? Yes X X X No X APPENDIX B STATE STREET CONDOS STORM WATER REQUIREMENTS APPLICABILITY CHECKLIST PART D: DETERMINE CONSTRUCTION SITE PRIORITY Part D: Determine Construction Site Priority 1. 2. 3. 4. X 1. 2. 3. 1. 2. 3. HIGH PRIORITY Projects where the site is 50 acres or more and grading will occur during the rainy season. Projects 5 acres or more and tributary to an impaired water body for sediment. Projects 5 acres or more within or directly adjacent to or discharging directly to a coastal lagoon or other receiving water within an environmentally sensitive area. Projects, active or inactive, adjacent or tributary to environmentally sensitive areas. MEDIUM PRIORITY Capital Improvement Projects where grading occurs, however, a Storm Water Pollution Prevention Plan (SWPPP) is not required under the State General Construction Permit (i.e. water and sewer replacement projects, intersection and street re-alignments, widening, comfort stations, etc.). Permit projects in the public right-of-way where grading occurs, such as installation of sidewalk, substantial retaining walls, curb and gutter for an entire street frontage, etc., however, SWPPPs are not required. Permit projects on private property where grading permits are required, however, Notice of Intents (NOIs) and SWPPPs are not required. LOW PRIORITY Capital Improvement Projects where minimal to no grading occurs, such as street light and loop installations, street light installations, etc. Permit projects in the public right-of-way where minimal to no grading occurs, such as pedestrian ramps, driveway additions, small retaining walls, etc. Permit projects on private property where grading permits are not required, such as small retaining walls, single-family homes, small tenant improvements, etc. APPENDIX C Table 1: Standard Development Project & Priority Project Storm Water BMP Requirements Matrix Standard Projects Site Design BMPs(l) R Source Control BMPs(2) R BMPs Applicable to Individual Priority Project Categories (3)a. Private RoadsO b. Residential Driveways & GuestParkingO 3 1 •3 & d o cQs-CO 8 8 S •o O e. Vehicle Wash AreasO f. Equipment Wash AreasO to 1 1> §•o 6 W) o h. Surface Parking AreasO CO & 1 O ff t•3 -8£5 a o Treatment Control BMPs(4) O Priority Projects: Detached Residential Development Attached Residential Development Commercial Development > 100,000 ft2 Automotive Repair Restaurants Hillside Development <5, 000 ft2 Parking Lots Streets, Highways, & Freeways R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R(5) R R R S S S S S S S S R = Required; select one or more applicable and appropriate BMPs from the applicable steps in Section III.2.a-d, or equivalent as identified in Appendix C. O = Optional or may be required by City Staff. As appropriate, applicants are encouraged to incorporate treatment control BMPs and BMPs applicable to individual priority project categories into the project design. City staff may require one or more of these BMPs, where applicable. S = Select one or more applicable and appropriate treatment control BMPs from Appendix C. (1) Refer to Section III.2. A. (2) Refer to Section III.2.B. (3) Priority Project categories must apply specific storm water BMP requirements, where applicable. Priority projects are subject to the requirements of all priority project categories that apply. (4) Refer to Section III.2.D. (5) Applies if the paved area totals >5,000 square feet or with >15 parkign spaces and is potentially exposed to urban run-off. Source: City of Carlsbad Public Works Department Standard Urban Storm Water Mitigation Plan Storm Water Standards (April 2003, page 8) Table 2: Anticipated and Potential Pollutants Generated by Land Use Type Project Categories Detached Residential Development Attached Residential Development Commercial Development > 100,000 ft2 Automotive Repair Restaurants Hillside Development <5, 000 ft2 Parking Lots Streets, Highways, & Freeways General Pollutant Categories Sediments X X pd) X pd) X Nutrients X X p(l) X pd) pd)X Heavy Metals X X X Organic Compounds p(2) X(4)(5) X<4) Trash & Debris X X X X X X X Oxygen Demanding Substances X pd) p(5) X X pd) p(5) Oil & Grease X p(2) X X X X X X Bacteria & Viruses X p(D p(3) X Pesticides X X p(5) X pd) Notes: X = Anticipated P = Potential ( 1 ) A potential pollutant if landscaping exists on-site. (2) A potential pollutant if the project includes uncovered parking areas. (3) A potential pollutant is land use involves food or animal waste areas. (4) Including petroleum hydrocarbons. (5) Including solvents. Source: City of Carlsbad Public Works Department Standard Urban Storm Water Mitigation Plan Storm Water Standards (April 2003, page 12) Table 3: Numeric Sizing Treatment Standards Volume 1. Volume-based BMPs shall be designed to mitigate (infiltrate, filter, or treat) the volume of run-off produced from a 24-Hour 85th percentile storm event, as determined from Isopluvial maps contained in the County of San Diego Hydrology Manual. OR Flow 2. Flow-based BMPs shall be designed to mitigate (infiltrate, filter, or treat) the maximum flow rate of run-off produced from a rainfall intensity of 0.2 inch of rainfall per hour for each hour of a storm event. Source: City of Carlsbad Public Works Department Standard Urban Storm Water Mitigation Plan Storm Water Standards (April 2003, page 20) Table 4: Structural Treatment Control BMP Selection Matrix Pollutant Of Concern Sediment Nutrient Heavy Metals Organic Compounds Trash & Debris Oxygen Demanding Substances Bacteria Oil& Grease Pesticides Notes: Treatment Control BMP Categories Biofilters M L M U L L U M U Detention Basins H M M U H M U M U Infiltration Basins (1) H M M U U M H U U Wet Ponds or Wetlands H M H U U M U U U Drainage Inserts L L L L M L L L L Filtration H M H M H M M H U Hydrodynamic Separator Systems (2> M L L L M L L L L (1) Including trenches and porous pavement. (2) Also known as hydrodynamic devices and baffle boxes L: Low removal efficiency M: Medium removal efficiency H: High removal efficiency U: Unknown removal efficiency Sources: Guidance Specifying Management Measures for Sources ofNonpoint Pollution in Coastal Waters (1993), National Stormwater Best Management Practices Database (2001), and Guide for BMP Selection in Urban Development Areas (2001). Source: City of Carlsbad Public Works Department Standard Urban Storm Water Mitigation Plan Storm Water Standards (April 2003, page 21) o Storm Water Standards 4/03/03 APPENDIX B DRAFT ENVIRONMENTALLY SENSITIVE AREAS WITHIN THE CITY OF CARLSBAD Environmentally Sensitive Areas Major Roads | | Carlsbad City Boundary ^Hl Environmentally Sensitive Areas e 5,800 2.900 0 jvcargi$2/()[oducls/pla!ining/(312 Q2/EnvSensAi eas 34 APPENDIX D PRELIMINARY HYDROLOGY STUDY FOR STATE STREET CONDOS Job No. 051117-04 Revised: December 21, 2005 Prepared: August 3, 2005 Prepared by: O'DAY CONSULTANTS, INC. 2710 Loker Avenue West, Suite 100 Carlsbad, California 92010-6609 Tel: (760)931-7700 Fax: (760)931-8680 George O'Day RCE 32014 Date Exp. 12/31/06 PRELIMINARY HYDROLOGY STUDY STATE STREET CONDOS TABLE OF CONTENTS ITEM PAGE COVER SHEET i TABLE OF CONTENTS ii 1.0 INTRODUCTION 1 1.1 PURPOSE OF STUDY 1 1.2 VICINITY MAP 1 1.3 SCOPE 1 1.4 HYDROLOGIC ANALYSIS 1 2.0 HYDROLOGY 2 2.1 RATIONAL METHOD DESCRIPTION 2 2.2 SOIL HYDROLOGIC GROUP DETERMINATION 2 2.3 HYDROLOGY CALCULATION KNOWN VARIABLES 3 3.0 EXISTING CONDITIONS ANALYSIS 3 3.1 EXISTING TIME OF CONCENTRATION 3 3.2 RAINFALL INTENSITY 3 3.3 EXISTING CONDITIONS DISCHARGE 4 4.0 PROPOSED CONDITION ANALYSIS 4 4.1 PROPOSED TIME OF CONCENTRATION 4 4.2 RAINFALL INTENSITY 5 4.3 PROPOSED CONDITIONS DISCHARGE 5 5.0 DETENTION 5 5.1 PERVIOUS PAVEMENT 5 5.2 PERVIOUS PAVEMENT AREAS 6 5.3 RUNOFF CONTRIBUTION 6 5.3.1 CENTER DRIVE AREA QUANTITY 6 5.3.2 NORTH ALLEY PARKING AREA QUANTITY 6 5.4 PERVIOUS PAVEMENT DESIGN CONCLUSION 7 Revised December 21,2005 -ii- 05-1117-5 August 3, 2005 PRELIMINARY HYDROLOGY STUDY STATE STREET CONDOS TABLE OF CONTENTS ITEM PAGE 6.0 CONCLUSION 7 7.0 ATTACHMENTS 8 ATTACHMENTS • VICINITY MAP (LARGE SCALE) • SAN DIEGO COUNTY HYDROLOGY MANUAL EXCERPTS (2003) 0 FIGURE 3-1: INTENSITY-DURATION DESIGN CHART O 100-YEAR RAINFALL ISOPLUVIAL-6 HOUR 0 100-YEAR RAINFALL ISOPLUVIAL - 24 HOUR 0 TABLE 3-1: RUNOFF COEFFICIENTS FOR URBAN AREAS O TABLE 3-2: MAXIMUM OVERLAND FLOW LENGTH & INITIAL TIME OF CONCENTRATION 0 FIGURE 3-3: RATIONAL FORMULA - OVERLAND TIME OF FLOW NOMOGRAPH 0 SOIL HYDROLOGIC MAP • CITY OF CARLSBAD DESIGN STANDARDS - CHAPTER 5 • PRELIMINARY HYDROLOGY STUDY EXHIBIT • CASQA SD-20: PERVIOUS PAVEMENT Revised December 21, 2005 - Hi - 05-1117-5 August 3, 2005 PRELIMINARY HYDROLOGY STUDY STATE STREET CONDOS 1.0 INTRODUCTION 1.1 PURPOSE OF STUDY This drainage study was prepared to determine runoff quantities for State Street Condos before and after development. 1.2 VICINITY MAP The State Street Condos are located as follows: CITY OF OCEANSIDE VICINITY MAP NO SCAL£ 1.3 SCOPE This study will analyze the 100-Year Design Storm Event Discharge for the State Street Condos site. 1.4 HYDROLOGIC ANALYSIS The existing condition of the site for the purposes of this report consists of several cottages, walkways and landscaping. The existing hydrology was analyzed in this study using runoff coefficients consistent with a medium-density residential development over Type 'B' soils (C=0.51) for the site. The existing Qi00 is 0.67 cfs. Revised December 21,2005 -1 - 05-1117-5 August 3, 2005 PRELIMINARY HYDROLOGY STUDY STATE STREET CONDOS The proposed developed condition for State Street Condos as shown on the Tentative Map consists of two multi-unit buildings being constructed on the north and south ends of the site with a drive aisle in the middle. A total of 6 residential units are being proposed. A majority of the runoff will flow via sheet flow and through roof drains into landscape areas and then continue to sheet flow to the gutter. In addition, the pavement between the two proposed buildings and the parking along the north alley will be porous pavement to encourage water infiltration. The TC of the developed State Street Condos (per the Tentative Map design) was assumed to be five minutes, due to the small area of the project (Ch. 5, Section 2.C - City of Carlsbad Engineering Standards, page 2 of 5). To be consistent with a high-density residential development over Type 'B' soils, a runoff coefficient of 0.67 was used. The Q100 for the proposed conditions is 1.05 cfs. 2.0 HYDROLOGY This hydrologic analysis was performed according to the 2003 San Diego County Hydrology Manual. The Rational Method was used to determine flows. The Rational Method estimates the peak rate of runoff at any location in a watershed as a function of the drainage area (A), runoff coefficient (C), and rainfall intensity (I) for a duration equal to the time of concentration (Tc), which is the time required for water to flow from the most remote point of the basin to the location being analyzed. 2.1 RATIONAL METHOD DESCRIPTION The rational method, as described in the San Diego County Hydrology Manual (2003), was used to estimate surface runoff flows. The basic equation: Q = CIA C = runoff coefficient (varies with surface) I = intensity (varies with time of concentration) A = area in acres In addition, the soil hydrologic group for the project site will also need to be determined first. 2.2 SOIL HYDROLOGIC GROUP DETERMINATION Per the Soil Hydrologic Groups Map in the San Diego County Hydrology Manual (2003), the soil group for the State Street Condos is Group 'B'. A copy of the Soil Hydrologic Groups Map is provided in Section 2: Attachments for reference. Revised December 21, 2005 - 2 - 05-1117-5 August 3, 2005 PRELIMINARY HYDROLOGY STUDY STATE STREET CONDOS 2.3 HYDROLOGY CALCULATION KNOWN VARIABLES The following are the known variables for the hydrology calculations A = area (acres) = 0.28 acres CExist = Existing runoff coefficient = 0.51 (Table 3-1) Cprop = Proposed runoff coefficient = 0.67 (Table 3-1) D = length of run = 150 (use 75 based on Table 3-2) P6 = 100 Year Storm Event 6 Hour Value = 2.5 in/hr S = slope = 2.0% 3.0 EXISTING CONDITION ANALYSIS By the rational method, as described in the San Diego County Hydrology Manual (2003), the surface runoff for the 100- Year Design Storm Event for the existing conditions is as follows: 3.1 EXISTING TIME OF CONCENTRATION Time of concentration is calculated as follows: Where: T; = 1.8 (1.1 -C) D '/2 sl/3 Therefore: Ti = [1.8 (1.1 -C) D'/2] /S 1/3 = [1.8(1.1-.67)(75)V4]/(2.0)1/3 = [(1.8) (.43) (8.66)] 71.2599 = 6.703/1.2599 = 5.32 minutes And: T; =5 minutes (per City of Carlsbad Standards for small areas) Therefore: Tc = Tt + TT = 5.32 + 5.0 = 10.32 minutes 3.2 RAINFALL INTENSITY Rainfall intensity is calculated as follows: Iioo = 7.44(P6)(TC^645) Therefore: I100 = 7.44 (P6) (Tc^645) = 7.44 (2.5) (10.32 = 7.44 (2.5) (0.2219) = 4.13in/nr RevisedDecember21,2005 -3- 05-1117-5 August 3, 2005 PRELIMINARY HYDROLOGY STUDY STATE STREET CONDOS 3.3 EXISTING CONDITIONS DISCHARGE Discharge is calculated as follows: Qioo = C x IIQO x A Therefore: Qioo = C x Iioo x A = (0.51)x(4.13)x(0.28) = 0.5898 cfs = 0.59 cfs This discharge is at Confluence Point A. Confluence Point A is at the intersection of the western alley and State Street, in the center of the cross gutter. 4.0 PROPOSED CONDITION ANALYSIS By the rational method, as described in the San Diego County Hydrology Manual (2003), the surface runoff for the 100-Year Design Storm Event for the proposed conditions is as follows: 4.1 PROPOSED TIME OF CONCENTRATION Time of concentration is calculated as follows: Where: T; Therefore: T; And: Therefore: Tc = 1.8(1.1-OD c 1/3 = [1.8(l.l-C)D/2]/S 1/3 = [(1.8) (.43) (8.66)] /1. 2599 = 6.703/1.2599 = 5.32 minutes = 5 minutes (per City of Carlsbad Standards for small areas) 5.32 + 5.0 10.32 minutes Revised December 21, 2005 August 3, 2005 -4-05-1117-5 PRELIMINARY HYDROLOGY STUDY STATE STREET CONDOS 4.2 RAINFALL INTENSITY Rainfall intensity is calculated as follows: I,oo =7.44(P6)(TC^645) Therefore: I100 = 7.44 (P6) (Tc^645) = 7.44 (2.5) (10.32-°'645) = 7.44 (2.5) (0.2219) = 4.13in/hr 4.3 PROPOSED CONDITIONS DISCHARGE Discharge is calculated as follows: Qioo = C x I10o x A Therefore: Qioo = C x Iioo x A = (0.67) x (4.13) x (0.28) = 0.7748 cfs = 0.78 cfs This discharge is at Confluence Point A. Confluence Point A is at the intersection of the western alley and State Street, in the center of the cross gutter. 5.0 DETENTION According to City of Carlsbad Standards any change in drainage patterns between an existing condition and proposed condition must be mitigated in order to preserve the down stream conditions. In order to accomplish this it is recommended that the State Street Condos detain the additional Qioo runoff of 0.19 cfs for the calculated time of concentration of 10.32 minutes. This will be accomplished in the following manner: 5.1 PERVIOUS PAVEMENT The paved portion of the State Street Condos between the two buildings (Center Drive Area) and the parking spaces on the north alley (North Alley Parking Area) will all be constructed using pervious pavement per CASQA SD-20: Pervious Pavement. Not only will this act as a treatment control BMP; but also will act as a detention facility for the excess runoff. A copy of this is provided in the attachments section. Revised December 21,2005 -5- 05-1117-5 August 3, 2005 PRELIMINARY HYDROLOGY STUDY STATE STREET CONDOS 5.2 PERVIOUS PAVEMENT AREAS The north alley will be required to detain the following additional runoff quantity: Total Pervious Pavement Area = 2445 ft2 This is split as follows: Center Drive Area = 1830 ft2 = 74.85% = 75% North Alley Parking Area = 615 ft2 = 25.15% = 25% 5.3 RUNOFF CONTRIBUTION Based on the proposed drainage patterns and their area contributions, the two pervious pavement sections will be required to detain the following quantities: Center Drive Area = 75% = 0.14 cfs North Alley Parking Area = 25% = .05 cfs 5.3.1 CENTER DRIVE AREA QUANTITY The Center Drive Area will need to detain and infiltrate 0.14 cfs over a time of 10.32 minutes. This means that the detention area must be as follows: Storage = 0.14 ft3/sec x 10.32 minutes x 60 seconds/minute = 0.14x10.32x60 = 86.69 ft3 At a design depth of one foot the total area of pervious pavement in the Center Drive Area is as follows: Actual Storage= area x length = 1830 ft2 x 1.0 ft = 1830 ft3 The actual storage capacity of 1830 ft3 is sufficient to retain and infiltrate the desired storage of 86.69 ft3. 5.3.2 NORTH ALLEY PARKING AREA QUANTITY The North Alley Parking Area will need to detain and infiltrate 0.15 cfs over a time of 10.32 minutes. This means that the detention area must be as follows: Storage = 0.05 ft3/sec x 10.32 minutes x 60 seconds/minute = 0.05 x 10.32 x 60 = 30.96 ft3 At a design depth of one foot the total area of pervious pavement in the North Alley Parking Area is as follows: Revised December 21,2005 -6- 05-1117-5 August 3, 2005 PRELIMINARY HYDROLOGY STUDY STATE STREET CONDOS Actual Storage= area x length = 615 ft2 x 1.0 ft = 615 ft3 The actual storage capacity of 615 ft3 is sufficient to retain and infiltrate the desired storage of 30.96 ft3. 5.4 PERVIOUS PAVEMENT DESIGN CONCLUSION The Center Drive Area will be able to detain and infiltrate 1830 ft3 and the North Alley Parking Area will be able to detain and infiltrate 615 ft3. This is a combined total of 2,445 ft3 of storage at a design depth of one foot. This well in excess of required storage capacity of 117.65 ft3 to detain and infiltrate 0.19 cfs for 10.32 minutes. 6.0 CONCLUSION The results of the analysis of State Street Condos Qioo at Confluence Point A is presented below: QIOO Analysis at Confluence Point A Confluence Point A Qioo Existing cfs 0.59 Qioo Proposed cfs 0.78 Qioo Difference cfs +0.19 The increase in Qioo of 0.19 cfs is due to the increase in the residential density of the proposed State Street Condos. The increase in residential density will increase the impervious surface area of the State Street Condos site. This increase will be retained and infiltrated by pervious pavement in the Center Drive Area and the North Alley Parking Areas. Revised December 21, 2005 August 3, 2005 -7-05-1117-5 PRELIMINARY HYDROLOGY STUDY STATE STREET CONDOS 7.0 ATTACHMENTS The following attachments are provided at the end of this report for the Preliminary Hydrology for the State Street Condos: • Vicinity Map (Large Scale) • San Diego County Hydrology Manual Excerpts (2003) o Figure 3-1: Intensity-Duration Design Chart o 100-Year Rainfall Isopluvial - 6 Hour o 100-Year Rainfall Isopluvial - 24 Hour o Table 3-1: Runoff Coefficients for Urban Areas o Table 3-2: Maximum Overland Flow Length & Initial Time of Concentration o Figure 3-3: Rational Formula - Overland Time of Flow Nomograph o Soil Hydrologic Map • City of Carlsbad Design Standards - Chapter 5 • Preliminary Hydrology Study Exhibit • CASQA SD-20: Pervious Pavement Revised December 21,2005 -8- 05-1117-5 August 3, 2005 SITE CITY OF OCEANSIDE HIGHWAY.. CITY OF VISTA CITY OF SAN MARCOS CITY OF ENCINITAS VICINITY MAP NO SCALE 10.0 9.0 8.0 7.0 6.0 5.0 4.0 3.0 2.0 SID 35" c08 |0.7 0.6 0.5 0.4 0.3 0.2 0.1 , ^^ N, S N s * — s s. s ^ s s S *( S * * s, i N s, NJ s s s s, s s, , s 1 ^ s •s S s s s "s ^ s s x s _ % V s, \ \ s s s * ^ s * s s - s N « \ > s » > s s, t ^ « s s( sk s * s, ^ k » s Nj '» s s •t \ s _„.. "S'v%x.'3v s'x'x''1 :':';'«,Ni'v:|:; s ^s",, ^s^ '•.,>»,X'sx>'i '"'-vs% ''i<s S N ' * *i ' ' i "*» ''''«» > ' i '""», I '" L i T 1 '•• n 1 = 7. = in P6= 6-1<;;; 1 D = DI v '' ''''' •!'''k''\" '''•',Nx>;;;:js::: > '''., v'j '''''' i!s L ''••.,,'] !|" vV ' 'l ^ x ''•., 1'1'i\ ''"1 ' ••••. q"t ' '' '''I '' , 's * 1 ' 1'< • '> 1 's i EQUATION 44 P6 j-j-0.645 ensity (in/hr) Hour Precipitation (in] jration (mtn) s s s \ ^ N S Si N 1 s N 1 S S ^ s N N S s s s s N S •« N N *\ * S S « S ^ ss »s S S ^ k s s % T s I':;-:: ^i **> '' '» '*S "vs '"' s » ' '« ''*,_ S "'s EEEEiEllii , 4. 5 6 7 8 9 10 15 20 30 40 50 1 2 34 Minutes HoursDuration T i o>i . i 1:,| Z, ' i ft n ^3:::s,:;: Is i ,''',,' 5.0 § "'«, t 4.5 •§> '"', i 4.o §•1 I ! - g CO 1* I ' • •••• -•] • 1.5 * ' ) 1 0 I I 5 6 Direct! (1)Fror for« Couintl- (2) Adjl the app (3) Plot (4) Drai (5) This bein Applies (a) Sele (c) Adji to!!*-" ons for Application: n precipitation maps determine 6 hr and 24 hr amounts ie selected frequency. These maps are included in the nty Hydrology Manual (10, 50, and 100 yr maps included e Design and Procedure Manual). jst 6 hr precipitation (if necessary) so that it Is within range of 45% to 65% of the 24 hr precipitation (not icaple to Desert). 6 hr precipitation on the right side of the chart. n s line through the point parallel to the plotted lines. line is the intensity-duration curve for the location g analyzed. itloti Form: scted frequency '&0 year • 2-5) in..Po^= 4,0 ,±a= (^> %<2> istedP6<2>= ^-^ in. min. in /hr Note: This chart replaces the Intensity-Duration-Frequency curves used since 1965. P6 Duration S 7 10 15 20 25 30 40 50 60 90 120 180 180 240 300 360 1 j 15 2 25 * 3 3S~ 4 45 S 55 6 ill I f * I 1 i 1 " t " i 1 I 263 1395 5,27 659 790 922'1054 1186 1317 1449 1581 ~212 1318.4J24 530 636i74ai848 954 1060 11 66'l272 IBS {253,337 421 505j596|674 758 842 927 1011 130 195J2.59 324 389 454i 519 584 649*713 778 108 1~62|215 269 323'377j_431 485 539 593 646 093 140187 233 280 3271 373 ! 420 467" 513 560 083 t24 166 207 249 290* 332 i 373 415 456 498 069 f 03[138 1 72 207 24l! 276 , 310 345 379 413 060 090118 149 179209!239 269 298 328 358 053 080 ! 06 1 33 1 59 1 86 212 ' 239 265 292 318 041 0 6t 0 82 1 02 1 23 1 43 1 63 1 84 2 04 2 25 2 45 034 ;6Sli06B 085 1 02 1 19 1 36 163 170 187 204 029 044.059 073 088 1 03 1 18 1 32 1 47 1 62 1 76 026,039052065078091 104 MS 131 144 157 022 033*043 0.54 065,076 087 098 108 119 130 019 !028'038 047 056 066 075 085 094 103 113 0)7 025033 042 050058 067 075 084 092 100 F 1 G U R E Intensity-Duration Design Chart - Template 3-1 133'Sff-33-301 33°1S- 33'W 32°45> 32°30' '15' 32'30' County of San Diego Hydrology Manual Rainfall Isopluvials 100 Year Rainfall Event - 6 Hours Isopluvial (Inches) CIS VI HI>. \in > v t • B»SANOAQM0<ral 33-301 Riverside County s\\-^c3nA! \\. \ \ ,• / ' \ \ \ \ • <\'. • **~~.J _ *!***,. /' x"*"- 33°00- 32"45' 32*30'32'30' County of San Diego Hydrology Manual Rainfall Isopluvials 100 Year Rainfall Event - 24 Hours Isopluvial (inches) CIS THIS MAP IS PROVIDED WTTHOUTWOR MnjCO. MCUJDMO, BUT NOT LJMTTB) TO. THE IMPU^ WARRAKTIESOF ftBWhWnvWUTY AW FmeSSFORAPWTICULAR PURPOSE. lit hM b**i n^oduod wnh 303 Miles San Diego County Hydrology Manual Date: June 2003 Section: Page: 3 6 of 26 Table 3-1 RUNOFF COEFFICIENTS FOR URBAN AREAS Land Use NRCS Elements Undisturbed Natural Terrain (Natural) Low Density Residential (LDR) Low Density Residential (LDR) Low Density Residential (LDR) Medium Density Residential (MDR) Medium Density Residential (MDR) Medium Density Residential (MDR) Medium Density Residential (MDR) High Density Residential (HDR) High Density Residential (HDR) Commercial/Industrial (N. Com) Commercial/Industrial (G. Com) Commercial/Industrial (O.P. Com) Commercial/Industrial (Limited I.) Commercial/Industrial (General I.) County Elements Permanent Open Space Residential, 1.0 DU/A or less Residential, 2.0 DU/A or less Residential, 2.9 DU/A or less Residential, 4.3 DU/A or less Residential, 7.3 DU/A or less Residential, 10.9 DU/A or less Residential, 14.5 DU/A or less Residential, 24.0 DU/A or less Residential, 43.0 DU/A or less Neighborhood Commercial General Commercial Office Professional/Commercial Limited Industrial General Industrial Runoff Coefficient ''C" Soil Type % IMPER. 0* 10 20 25 30 40 45 50 65 80 80 85 90 90 95 A 0.20 0.27 0.34 0.38 0.41 0.48 0.52 0.55 0.66 0.76 0.76 0.80 0.83 0.83 0.87 B 0.25 0.32 0.38 0.41 0.45 0.51 0.54 0.58 0.67 0.77 0.77 0.80 0.84 0.84 0.87 c 0.30 0.36 0.42 0.45 0.48 0.54 0.57 0.60 0.69 0.78 0.78 0.81 0.84 0.84 0.87 D 0.35 0.41 0.46 0.49 0.52 0.57 0.60 0.63 0.71 0.79 0.79 0.82 0.85 0.85 0.87 *The values associated with 0% impervious may be used for direct calculation of the runoff coefficient as described in Section 3.1.2 (representing the pervious runoff coefficient, Cp, for the soil type), or for areas that will remain undisturbed in perpetuity. Justification must be given that the area will remain natural forever (e.g., the area is located in Cleveland National Forest). DU/A = dwelling units per acre NRCS = National Resources Conservation Service 3-6 San Diego County Hydrology Manual Date: June 2003 Section: Page: 3 12 of 26 Note that the Initial Time of Concentration should be reflective of the general land-use at the upstream end of a drainage basin. A single lot with an area of two or less acres does not have a significant effect where the drainage basin area is 20 to 600 acres. Table 3-2 provides limits of the length (Maximum Length (LM)) of sheet flow to be used in hydrology studies. Initial T; values based on average C values for the Land Use Element are also included. These values can be used in planning and design applications as described below. Exceptions may be approved by the "Regulating Agency" when submitted with a detailed study. Table 3-2 MAXIMUM OVERLAND FLOW LENGTH (LM) & INITIAL TIME OF CONCENTRATION (TQ Element* Natural LDR LDR LDR MDR MDR MDR MDR HDR HDR N. Com G. Com O.P./Com Limited I. General I. DLV Acre 1 2 2.9 4.3 7.3 10.9 14.5 24 43 .5% LM 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 Ti 13.2 12.2 11.3 10.7 10.2 9.2 8.7 8.2 6.7 5.3 5.3 4.7 4.2 4.2 3.7 1% LM 70 70 70 70 70 65 65 65 65 65 60 60 60 60 60 Ti 12.5 11.5 10.5 10.0 9.6 8.4 7.9 7.4 6.1 4.7 4.5 4.1 3.7 3.7 3.2 2% LM 85 85 85 85 80 80 80 80 75 75 75 75 70 70 70 Ti 10.9 10.0 9.2 8.8 8.1 7.4 6.9 6.5 5.1 4.0 4.0 3.6 3.1 3.1 2.7 3% LM 100 100 100 95 95 95 90 90 90 85 85 85 80 80 80 Ti 10.3 9.5 8.8 8.1 7.8 7.0 6.4 6.0 4.9 3.8 3.8 3.4 2.9 2.9 2.6 5% LM 100 100 100 100 100 100 100 100 95 95 95 90 90 90 90 T; 8.7 8.0 7.4 7.0 6.7 6.0 5.7 5.4 4.3 3.4 3.4 2.9 2.6 2.6 2.3 10% LM 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 T; 6.9 6.4 5.8 5.6 5.3 4.8 4.5 4.3 3.5 2.7 2.7 2.4 2.2 2.2 1.9 *See Table 3-1 for more detailed description 3-12 100 tuLULL 111o I92Q LU 1Ooa:LU I EXAMPLE: Given: Watercourse Distance (D) = 70 Feet Slope (s) =1.3% Runoff Coefficient (C) = 0.41 Overland Flow Time (T) = 9.5 Minutes SOURCE: Airport Drainage, Federal Aviation Administration, 1965 _ FIGURE Rational Formula - Overland Time of Flow Nomograph 3-3 <o 32«30' County of San Diego Hydrology Manual Soil Hydrologic Groups Legend Soil Groups Group A Group C Group D j | Undetermined Data Unavailable THIS MAP IS PROVIDED WFTHOUT WARRANTY OF AMY KIM], EITHEROR IMPLIED. INCLUDING. BUT NOT LI F/~OF MERCHANTABILITY AND FITNESS FConyrtgnt SwiGiS Ml Rlgtiti RewrvwJ Thli product! m«y arrafa Irttnnmon from Hw SANDAQ Ri 303 Miles CHAPTER 5- DRAINAGE AND STORM DRAIN STANDARDS 1. GENERAL A All drainage design and requirements shall be in accordance with the latest City of Carlsbad Standard Urban Storm Water Mitigation Plan (SUSMP), Jurisdictional Urban Runoff Management Plan (JURMP), Master Drainage and Storm Water Quality Management Plan and the requirements of the City Engineer and be based on full development of upstream tributary basins. B. Public drainage facilities shall be designed to carry the ten-year six-hour storm underground and the 100-year six-hour storm between the top of curbs. All culverts shall be designed to accommodate a 100-year six-hour storm with a one foot freeboard at entry conditions such as inlets and head walls. C. The use of underground storm drain systems, in addition to standard curb and gutter shall be required: 1) When flooding or street overflow during 100-year six-hour storm cannot be maintained between the top of curbs. 2) When 100-year six-hour storm flow from future upstream development (as proposed in the existing General Plan) will cause damage to structures and improvements. 3) When existing adequate drainage facilities are available for use (adjacent to proposed development). 4) When more than one travel lane of arterial and collector streets would be obstructed by 10-year 6-hour storm water flow. Special consideration will be required for super-elevated streets. D. The use of underground storm drain systems may be required: 1) When the water level in streets at the design storm is within 1" of top of curb. 2) When velocity of water in streets exceeds 11 FPS. 3) When the water travels on surface street improvements for more than 1,000'. E. The type of drainage facility shall be selected on the basis of physical and cultural adaptability to the proposed land use. Open channels may be considered in lieu of underground systems when the peak flow exceeds the capacity of a 48" diameter RCP. Fencing of open channels may be required as determined by the City Engineer. F. Permanent drainage facilities and right-of-way, including access, shall be provided from development to point of approved disposal. Page 1 of 5 G Storm Drains constructed at a depth of 15' or greater measured from finish grade to the top of pipe or structure shall be considered deep storm drains and should be avoided if at all possible. When required, special design consideration will be required to the satisfaction of the City Engineer. Factors considered in the design will include: 1) Oversized specially designed access holes/air shafts 2) Line encasements 3) Oversizing lines 4) Increased easement requirements for maintenance access 5) Water-tight joints 6) Additional thickness of storm drain The project designer should meet with the planchecker prior to initiation of design to review design parameters. H. Concentrated drainage from lots or areas greater than 0.5 acres shall not be discharged to City streets unless specifically approved by the City Engineer. I. Diversion of drainage from natural or existing basins is discouraged. J. Drainage design shall comply with the City's Jurisdictional Urban Runoff Management Plan (JURMP) and requirements of the National Pollutant Discharge Elimination System (NPDES) permit. 2. HYDROLOGY A Off site, use a copy of the latest edition City 400-scale topographic mapping. Show existing culverts, cross-gutters and drainage courses based on field review. Indicate the direction of flow; clearly delineate each drainage basin showing the area and discharge and the point of concentration. B. On site, use the grading plan. If grading is not proposed, then use a 100-scale plan or greater enlargement. Show all proposed and existing drainage facilities and drainage courses. Indicate the direction of flow. Clearly delineate each drainage basin showing the area and discharge and the point of concentration. C. Use the charts in the San Diego County Hydrology Manual for finding the "Tc" and "I". For small areas, a five minute "Tc" may be utilized with prior approval of the City Engineer. D. Use the existing or ultimate development, whichever gives the highest "C" factor. E. Use the rational formula Q = CIA for watersheds less than 0.5 square mile unless an alternate method is approved by the City Engineer. For watersheds in excess of 0.5 square mile, the method of analysis shall be approved by the City Engineer prior to submitting calculations. Page 2 of 5 3. HYDRAULICS A Street - provide: 1) Depth of gutter flow calculation. 2) Inlet calculations. 3) Show gutter flow Q, inlet Q, and bypass Q on a plan of the street. B. Storm Drain Pipes and Open Channels - provide: 1) Hydraulic loss calculations for: entrance, friction, junction, access holes, bends, angles, reduction and enlargement. 2) Analyze existing conditions upstream and downstream from proposed system, to be determined by the City Engineer on a case-by-case basis. 3) Calculate critical depth and normal depth for open channel flow conditions. 4) Design for non-silting velocity of 2 FPS in a two-year frequency storm unless otherwise approved by the City Engineer. 5) All pipes and outlets shall show HGL, velocity and Q value(s) for design storm. 6) Confluence angles shall be maintained between 45° and 90° from the main upstream flow. Flows shall not oppose main line flows. 4. INLETS A Curb inlets at a sump condition should be designated for two CFS per lineal foot of opening when headwater may rise to the top of curb. B. Curb inlets on a continuous grade should be designed based on the following equation: Q = 0.7 L (a + y)3/2 Where: y = depth of flow in approach gutter in feet a = depth of depression of flow line at inlet in feet L = length of clear opening in feet (maximum 30 feet) Q = flow in CFS, use 100-year design storm minimum C. Grated inlets should be avoided. When necessary, the design should be based on the Bureau of Public Roads Nomographs (now known as the Federal Highway Administration). All grated inlets shall be bicycle proof. D. All catch basins shall have an access hole in the top unless access through the grate section satisfactory to the City Engineer is provided. Page 3 of 5 E. Catch basins/curb inlets shall be located so as to eliminate, whenever possible, cross gutters. Catch basins/curb inlets shall not be located within 5' of any curb return or driveway. F. Minimum connector pipe for public drainage systems shall be 18". G Flow through inlets may be used when pipe size is 24" or less and open channel flow characteristics exist. 5. STORM DRAINS A. Minimum pipe slope shall be .005 (.5%) unless otherwise approved by the City Engineer. B. Minimum storm drain, within public right-of-way, size shall be 18" diameter. C. Provide cleanouts at 300' maximum spacing, at angle points and at breaks in grade greater than 1%. For pipes 48" in diameter and larger, a maximum spacing of 500' may be used. When the storm drain clean-out Type A dimension of "V" less "Z" is greater than 18", a storm drain clean-out Type B shall be used. D. The material for storm drains shall be reinforced concrete pipe designed in conformance with San Diego County Flood Control District's design criteria, as modified by Carlsbad Standard Specifications. Corrugated steel pipe shall not be used. Plastic/rubber collars shall be prohibited. E. Horizontal curve design shall conform to manufacturer recommended specifications. Vertical curves require prior approval from the City Engineer. F. The pipe invert elevations, slope, pipe profile line and hydraulic grade line for design flows shall be delineated on the mylar of the improvement plans. Any utilities crossing the storm drain shall also be delineated. The strength classification of any pipe shall be shown on the plans. Minimum D-load for RCP shall be 1350 in all City streets or future rights-of-way. Minimum D-load for depths less than 2', if allowed, shall be 2000 or greater. G For all drainage designs not covered in these Standards, the current San Diego County Hydrology and Design and Procedure Manuals shall be used. H. For storm drain discharging into unprotected or natural channel, proper energy dissipation measures shall be installed to prevent damage to the channel or erosion. In cases of limited access or outlet velocities greater than 18 fps, a concrete energy dissipater per SDRS D-41 will be required. Page 4 of 5 I. The use of detention basins to even out storm peaks and reduce piping is permitted with substantiating engineering calculation and proper maintenance agreements. Detention basins shall be fenced. J. Desiltation measures for silt caused by development shall be provided and cleaned regularly during the rainy season (October 1 to April 30) and after major rainfall as required by the City Engineer or his designated representative. Adequate storage capacity as determined by the City Engineer shall be maintained at all times. K. Protection of downstream or adjacent properties from incremental flows (caused by change from an undeveloped to a developed site) shall be provided. Such flows shall not be concentrated and directed across unprotected adjacent properties unless an easement and storm drains or channels to contain flows are provided. L. Unprotected downstream channels shall have erosion and grade control structures installed to prevent degradation, erosion, alteration or downcutting of the channel banks. M. Storm drain pipes designed for flow meeting or exceeding 20 feet per second will require additional cover over invert reinforcing steel as approved by the City Engineer. N. Storm drain pipe under pressure flow for the design storm, i.e., HGL above the soffit of the ape, shall meet the requirements of ASTM C76, C361, C443 for water-tight joints in the sections of pipe calculated to be under pressure and an additional safety length beyond the pressure flow point. Such safety length shall be determined to the satisfaction of the City Engineer taking into consideration such factors as pipe diameter, Q, and velocity. O. An all weather access road from a paved public right-of-way shall be constructed to all drainage and utility improvements. The following design parameters are required: Maximum grade 14%, 15 MPH speed, gated entry, minimum paved width 12 feet, 38' minimum radius, paving shall be a minimum of 4" AC over 4" Class II AB, turnaround required if over 300'. Work areas should be provided as approved by the plan checker. Access roads should be shown on the tentative project approval to ensure adequate environmental review. P. Engineers are encouraged to gravity drain all lots to the street without use of a yard drain system. On projects with new street improvements proposed, a curb outlet per SDRSD D-27 shall be provided for single-family residential lots to allow yard drains to connect to the streets gutter. Page 5 of 5 Pervious Pavements SD-20 Design Objectives J Maximize Infiltration J Provide Retention J Slow Runoff y Minimize Impervious Land Coverage Prohibit Dumping of Improper Materials Contain Pollutants Collect and Convey Description Pervious paving is used for light vehicle loading in parking areas. The term describes a system comprising a load-bearing, durable surface together with an underlying layered structure that temporarily stores water prior to infiltration or drainage to a controlled outlet. The surface can itself be porous such that water infiltrates across the entire surface of the material (e.g., grass and gravel surfaces, porous concrete and porous asphalt), or can be built up of impermeable blocks separated by spaces and joints, through which the water can drain. This latter system is termed 'permeable' paving. Advantages of pervious pavements is that they reduce runoff volume while providing treatment, and are unobtrusive resulting in a high level of acceptability. Approach Attenuation of flow is provided by the storage within the underlying structure or sub base, together with appropriate flow controls. An underlying geotextile may permit groundwater recharge, thus contributing to the restoration of the natural water cycle. Alternatively, where infiltration is inappropriate (e.g., if the groundwater vulnerability is high, or the soil type is unsuitable), the surface can be constructed above an impermeable membrane. The system offers a valuable solution for drainage of spatially constrained urban areas. Significant attenuation and improvement in water quality can be achieved by permeable pavements, whichever method is used. The surface and subsurface infrastructure can remove both the soluble and fine particulate pollutants that occur within urban runoff. Roof water can be piped into the storage area directly, adding areas from which the flow can be attenuated. Also, within lined systems, there is the opportunity for stored runoff to be piped out for reuse. Suitable Applications Residential, commercial and industrial applications are possible. The use of permeable pavement may be restricted in cold regions, arid regions or regions with high wind erosion. There are some specific disadvantages associated with permeable pavement, which are as follows: • Permeable pavement can become clogged if improperly installed or maintained. However, this is countered by the ease with which small areas of paving can be cleaned or replaced when blocked or damaged. January 2003 California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbooks.com 1 of 10 ^ SD-20 Pervious Pavements • Their application should be limited to highways with low traffic volumes, axle loads and speeds (less than 30 mph limit), car parking areas and other lightly trafficked or non- trafficked areas. Permeable surfaces are currently not considered suitable for adoptable roads due to the risks associated with failure on high speed roads, the safety implications of ponding, and disruption arising from reconstruction. • When using un-lined, infiltration systems, there is some risk of contaminating groundwater, depending on soil conditions and aquifer susceptibility. However, this risk is likely to be small because the areas drained tend to have inherently low pollutant loadings. • The use of permeable pavement is restricted to gentle slopes. • Porous block paving has a higher risk of abrasion and damage than solid blocks. Design Considerations Designing New Installations If the grades, subsoils, drainage characteristics, and groundwater conditions are suitable, permeable paving may be substituted for conventional pavement on parking areas, cul de sacs and other areas with light traffic. Slopes should be flat or very gentle. Scottish experience has shown that permeable paving systems can be installed in a wide range of ground conditions, and the flow attenuation performance is excellent even when the systems are lined. The suitability of a pervious system at a particular pavement site will, however, depend on the loading criteria required of the pavement. Where the system is to be used for infiltrating drainage waters into the ground, the vulnerability of local groundwater sources to pollution from the site should be low, and the seasonal high water table should be at least 4 feet below the surface. Ideally, the pervious surface should be horizontal in order to intercept local rainfall at source. On sloping sites, pervious surfaces maybe terraced to accommodate differences in levels. Design Guidelines The design of each layer of the pavement must be determined by the likely traffic loadings and their required operational life. To provide satisfactory performance, the following criteria should be considered: • The subgrade should be able to sustain traffic loading without excessive deformation. • The granular capping and sub-base layers should give sufficient load-bearing to provide an adequate construction platform and base for the overlying pavement layers. • The pavement materials should not crack of suffer excessive rutting under the influence of traffic. This is controlled by the horizontal tensile stress at the base of these layers. There is no current structural design method specifically for pervious pavements. Allowances should be considered the following factors in the design and specification of materials: 2 of 10 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Pervious Pavements SD-20 • Pervious pavements use materials with high permeability and void space. All the current UK pavement design methods are based on the use of conventional materials that are dense and relatively impermeable. The stiffness of the materials must therefore be assessed. • Water is present within the construction and can soften and weaken materials, and this must be allowed for. • Existing design methods assume full friction between layers. Any geotextiles or geomembranes must be carefully specified to minimize loss of friction between layers. • Porous asphalt loses adhesion and becomes brittle as air passes through the voids. Its durability is therefore lower than conventional materials. The single sized grading of materials used means that care should be taken to ensure that loss of finer particles between unbound layers does not occur. Positioning a geotextile near the surface of the pervious construction should enable pollutants to be trapped and retained close to the surface of the construction. This has both advantages and disadvantages. The main disadvantage is that the filtering of sediments and their associated pollutants at this level may hamper percolation of waters and can eventually lead to surface ponding. One advantage is that even if eventual maintenance is required to reinstate infiltration, only a limited amount of the construction needs to be disturbed, since the sub-base below the geotextile is protected. In addition, the pollutant concentration at a high level in the structure allows for its release over time. It is slowly transported in the stormwater to lower levels where chemical and biological processes may be operating to retain or degrade pollutants. The design should ensure that sufficient void space exists for the storage of sediments to limit the period between remedial works. • Pervious pavements require a single size grading to give open voids. The choice of materials is therefore a compromise between stiffness, permeability and storage capacity. • Because the sub-base and capping will be in contact with water for a large part of the time, the strength and durability of the aggregate particles when saturated and subjected to wetting and drying should be assessed. • A uniformly graded single size material cannot be compacted and is liable to move when construction traffic passes over it. This effect can be reduced by the use of angular crushed rock material with a high surface friction. In pollution control terms, these layers represent the site of long term chemical and biological pollutant retention and degradation processes. The construction materials should be selected, in addition to their structural strength properties, for their ability to sustain such processes. In general, this means that materials should create neutral or slightly alkaline conditions and they should provide favorable sites for colonization by microbial populations. Construction/Inspection Considerations • Permeable surfaces can be laid without cross-falls or longitudinal gradients. • The blocks should be lain level January 2003 California Stormwater BMP Handbook 3 of 10 New Development and Redevelopment www.cabmphandbooks.com SD-20 Pervious Pavements • They should not be used for storage of site materials, unless the surface is well protected from deposition of silt and other spillages. • The pavement should be constructed in a single operation, as one of the last items to be built, on a development site. Landscape development should be completed before pavement construction to avoid contamination by silt or soil from this source. • Surfaces draining to the pavement should be stabilized before construction of the pavement. • Inappropriate construction equipment should be kept away from the pavement to prevent damage to the surface, sub-base or sub-grade. Maintenance Requirements The maintenance requirements of a pervious surface should be reviewed at the time of design and should be clearly specified. Maintenance is required to prevent clogging of the pervious surface. The factors to be considered when defining maintenance requirements must include: • Type of use • Ownership • Level of trafficking • The local environment and any contributing catchments Studies in the UK have shown satisfactory operation of porous pavement systems without maintenance for over 10 years and recent work by Imbe et al. at Qth ICUD, Portland, 2002 describes systems operating for over 20 years without maintenance. However, performance under such regimes could not be guaranteed, Table i shows typical recommended maintenance regimes: 4 of 10 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Pervious Pavements SD-20 Table 1 Typical Recommended Maintenance Regimes Activity Minimize use of salt or grit for de-icing Keep landscaped areas well maintained Prevent soil being washed onto pavement Vacuum clean surface using commercially available sweeping machines at the following times: End of winter (April) Mid-summer (July / August) After Autumn leaf-fall (November) Inspect outlets If routine cleaning does not restore infiltration rates, then reconstruction of part of the whole of a pervious surface may be required. The surface area affected by hydraulic failure should be lifted for inspection of the internal materials to identify the location and extent of the blockage. Surface materials should be lifted and replaced after brush cleaning. Geotextiles may need complete replacement. Sub-surface layers may need cleaning and replacing. Removed silts may need to be disposed of as controlled waste. Schedule Ongoing 2/3 x per year Annual As needed (infrequent) Maximum 15-20 years Permeable pavements are up to 25 % cheaper (or at least no more expensive than the traditional forms of pavement construction), when all construction and drainage costs are taken into account. (Accepting that the porous asphalt itself is a more expensive surfacing, the extra cost of which is offset by the savings in underground pipework etc.) (Niemczynowicz, et al., 1987) Table i gives US cost estimates for capital and maintenance costs of porous pavements (Landphair et al., 2000) Redeveloping Existing Installations Various jurisdictional stormwater management and mitigation plans (SUSMP, WQMP, etc.) define "redevelopment" in terms of amounts of additional impervious area, increases in gross floor area and/or exterior construction, and land disturbing activities with structural or impervious surfaces. The definition of" redevelopment" must be consulted to determine whether or not the requirements for new development apply to areas intended for redevelopment. If the definition applies, the steps outlined under "designing new installations" above should be followed. January 2003 California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbooks.com 5 of 10 SD-20 Pervious Pavements Additional Information Cosf Considerations Permeable pavements are up to 25 % cheaper (or at least no more expensive than the traditional forms of pavement construction), when all construction and drainage costs are taken into account. (Accepting that the porous asphalt itself is a more expensive surfacing, the extra cost of which is offset by the savings in underground pipework etc.) (Niemczynowicz, et al., 1987) Table 2 gives US cost estimates for capital and maintenance costs of porous pavements (Landphair et al., 2000) 6 of 10 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Pervious Pavements SD-20 Table 2 Engineer's Estimate for Porous Pavement Porous Pavement Mem Grading Paving Excavation FIHer Fabrfc Stone Fill Sand Sight We» Seeding Cheek Dam UBilS SY SY CY SY CY CY EA LF CY Prtw $2.00 $19.00 $3.60 $1-15 $16.00 $7.00 $300.00 $0.05 53S.OO Total Construction Costs Construction Costs Amortized for 20 Years Cyctas/ Ywr Qewrt.1 AweWS 604 212 201 790 201 100 2 $44 0 Total $1,208 $4,026 $724 $805 $3,216 $700 $600 $92 $0 $10,105 $505 Quint I AereWS 1209 424 403 1400 403 200 3 i2$e 0 ToW $2,418 $8,056 $1,451 $1.610 $6,448 $1,400 $900 $64 $0 $iii*a *99fl Qnaet.3 AcreWS 1812: 636 604 2000 604 300 4 1932 0 Total $3,624 $12,0*4 $2,174 $2,300 $9,004 $2,100 $1,200 $97 $0 $29,619 IMI1 Quint 4 AereWS 2419 848 806 2800 806 400 7 2576 0 ToliI $4,838 $16,112 $2,902 $3,220 $12,696 $2,800 $2,100 $129 *0 $40,158 $2,008 Qw««,5 AcreWS 3020 1060 1008 3600 1008 500 7 3220 0 TaW $6,040 $20,140 $3,62$ $4,140 $16,128 $3,500 $2,100 $161 $0 $49,79* $2,490 Annual Maintenance Expense Item Sweeping Washing Inspection D*ep Clean UniU AG AC tm AC Price $250.00 $250-00 $20.00 $450-00 Cy«le»/ Y«ir 6 6 5 0.5 QwwM Acr?WS 1 1 5 1 Total Annual Maintenance Expense Total $1,500 $1,500 $100 $225 $3,980 Qq»nL2 AcrvWS 2 2 5 2 Total $3,000 $3,000 $100 $450 *7,7»2 Qejnrt.3 AtreWS 3 3 S 3 Tatal $4^00 $4,500 $100 $875 $11,851 Quint 4 AereWS 4 4 5 3.S Toll! $6,000 $6,000 $100 $878 $15,433 Qoanl.S AtnVtS 5 9 5 5 Tolrf $7,500 $7,500 $100 $1,125 $19,370 January 2003 California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbobks.com 7 of 10 SD-20 Pervious Pavements Supplemental Information Other Resources Abbott C.L. and Comino-Mateos L. 2001. In situ performance monitoring of an infiltration drainage system and field testing of current design procedures. Journal CIWEM, 15(3), pp. 202. Construction Industry Research and Information Association (CIRIA). 2002. Source Control using Constructed Pervious Surfaces €582, London, SWiP 3AU. Construction Industry Research and Information Association (CIRIA). 2000. Sustainable urban drainage systems - design manual for Scotland and Northern Ireland Report €521, London, SWiP Construction Industry Research and Information Association (CIRIA). 2000 C522 Sustainable urban drainage systems - design manual for England and Wales, London, SWiP sAU. Construction Industry Research and Information Association (CIRIA). RP448 Manual of good practice for the design, construction and maintenance of infiltration drainage systems for stormwater runoff control and disposal, London, SWiP Dierkes C., Kuhlmann L., Kandasamy J. & Angelis G. Pollution Retention Capability and Maintenance of Permeable Pavements. Proc 9th International Conference on Urban Drainage, Portland Oregon, September 2002. Hart P (2002) Permeable Paving as a Stormwater Source Control System. Paper presented at Scottish Hydraulics Study Group 14th Annual seminar, SUDS. 22 March 2002, Glasgow. Kobayashi M., 1999. Stormwater runoff control in Nagoya City. Proc. 8 th Int. Conf. on Urban Storm Drainage, Sydney, Australia, pp.8 25-833. Landphair, H., McFalls, J., Thompson, D., 2000, Design Methods, Selection, and Cost Effectiveness of Stormwater Quality Structures, Texas Transportation Institute Research Report 1837-1, College Station, Texas. Legret M, Colandini V, Effects of a porous pavement with reservior strucutre on runoff watenwater quality and the fate of heavy metals. Laboratoire Central Des Fonts et Chaussesss Macdonald K. & Jefferies C. Performance Comparison of Porous Paved and Traditional Car Parks. Proc. First National Conference on Sustainable Drainage Systems, Coventry June 2001. Niemczynowicz J, Hogland W, 1987: Test of porous pavements performed in Lund, Sweden, in Topics in Drainage Hydraulics and Hydrology. BC. Yen (Ed.), pub. Int. Assoc. For Hydraulic Research, pp 19-80. Pratt C.J. SUSTAINABLE URBAN DRAINAGE - A Review of published material on the performance of various SUDS devices prepared for the UK Environment Agency. Coventry University, UK December 2001. 8 of 10 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com -***»'Pervious Pavements SD-20 Pratt C.J., 1995. Infiltration drainage - case studies of UK practice. Project Report 22,Construction Industry Research and Information Association, London, SWiP 3AU; also known as National Rivers Authority R & D Note 485 Pratt. C. J., 1990. Permeable Pavements for Stormwater Quality Enhancement. In: Urban Stormwater Quality Enhancement - Source Control, retrofitting and combined sewer technology, Ed. H.C. Torno, ASCE, ISBN 087262 7594, pp. 131-155 Raimbault G., 1997 French Developments in Reservoir Structures Sustainable water resources I the 21st century. Malmo Sweden Schliiter W. & Jefferies C. Monitoring the outflow from a Porous Car Park Proc. First National Conference on Sustainable Drainage Systems, Coventry June 2001. Wild, T.C., Jefferies, C., and D'Arcy, B.J. SUDS in Scotland - the Scottish SUDS database Report No SR(O2)o9 Scotland and Northern Ireland Forum for Environmental Research, Edinburgh. In preparation August 2002. January 2003 California Stormwater BMP Handbook 9 of 1 New Development and Redevelopment www.cabmphandbooks.com SD-20 Pervious Pavements Q&0t3XMlK • •- -— t— <~~- • , •: ,«.« „. rt, ,,j v * Y r 1 1 ImpermeableMembrane • ..... •• ••- , iPermeaWs •• , ' (_~-JL.__ — -- -,.«.,.] Overflow ' , dsposai Geoiexllie * * * * * Sub-base or reuse mfitalion (a) Pervious pavement used tot attenuation (b| Pervious pavement used lor InfWratlon Schematics of a Pervious Pavement System 10 of 10 California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbooks.com January 2003 APPENDIX E Table 2-3. BENEFICIAL USES OF COASTAL WATERS Coastal Waters Hydrologic Unit Basin Number BENEFICIAL USE I N D N A V R E C 1 R E C 2 C o M M Coastal Lagoons - continued 2Buena Vista Lagoon Loma Alta Slough Mouth of San Luis Rey River Santa Margarita Lagoon Aliso Creek Mouth San Juan Creek Mouth San Mateo Creek'Mouth San Onofre Creek Mouth 4.21 4.10 3.11 2.11 1.13 1.27 1.40 1.51 • • • • • • • • • • • • • • • • B I 0 L • • E S T 0 • • W I L D R A R E • • • • • • • • • • • • • • • • M A R A Q U A M I G R S P W N • • • • • • • • • • • • • • • • W A R M • S H E L L • 1 Includes ihe tidal prisms of the Otay and Sweet water Rivers. 2 Fishing from shore or boat permitted, but other water contact recreational (REC-1) uses are prohibited. • Existing Beneficial Use 0 Potential Beneficial Use Table 2-3 BENEFICIAL USES 2-48 March 12, 1997 APPENDIX F c 2002 CWA SECTION 303(d) LIST OF WATER QUALITY LIMITED SEGMENT SAN DIEGO REGIONAL WATER QUALITY CONTROL BOARD Approved by USE PA: July 2003 REGION TYPE NAME R Agua Hedionda Creek 9 R Aliso Creek CALWATER WATERSHED POLLUTANT/STRESSOR POTENTIA SOURCES TMDL ESTIMATED PRIORITY SIZE AFFECTED PROPOSED TMDL COMPLETION 90431000 Total Dissolved Solids Low Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source 90113000 Bacteria Indicators Medium Urban Runoff/Storm Sewers Unknown point source Nonpoint/Point Source Phosphorus Low Impairment located at lower 4 miles. Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source Toxicity Low Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source 7 Miles 9 E Agua Hedionda Lagoon 90431000 Bacteria Indicators Sedimentation/Siltation Low Nonpoint/Point Source Low Nonpoint/Point Source 6.8 Acres 6.8 Acres 19 Miles 19 Miles 19 Miles 9 E Aliso Creek (mouth)90113000 Bacteria Indicators Medium Nonpoint/Point Source 0.29 Acres 9 E Buena Vista Lagoon 90421000 Bacteria Indicators Low Nonpoint/Point Source Nutrients Low Estimated size of impairment is 150 acres located in upper portion of lagoon. Nonpoint/Point Source Sedimentation/Siltation Medium Nonpoint/Point Source 202 Acres 202 Acres 202 Acres Page I of 16 2002 CWA SECTION 303(d) LIST OF WATER QUALITY LIMITED SEGMENT SAN DIEGO REGIONAL WATER QUALITY CONTROL BOARD ' CALWATER POTENTIAL REGION TYPE NAME WATERSHED POLLUTANT/STRESSOR SOURCES 9 R Chollas Creek 90822000 Bacteria Indicators Cadmium Copper Diazinon Lead Zinc NonpointyPoint Source Nonpoint/Point Source Nonpoint/Point Source Nonpoint/Point Source Nonpoint/Point Source Nonpoint/Point Source 1TMDL ESTIMATED PROPOSED TMDL PRIORITY SIZE AFFECTED COMPLETION Medium High High High High High 1.2 Miles 1.2 Miles 1.2 Miles 1.2 Miles 1.2 Miles 1.2 Miles 2004 2004 2002 2004 2004 R Cloverdale Creek 90532000 Phosphorus Total Dissolved Solids Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source Low Low 1.2 Miles 1.2 Miles B Dana Point Harbor 90114000 Bacteria Indicators Medium Impairment located at Baby Beach. Urban Runoff/Storm Sewers Marinas and Recreational Boating Unknown Nonpoint Source Unknown point source 119 Acres E Famosa Slough and Channel 90711000 Eutrophic Low Nonpoint Source 32 Acres Page 2 of 16 2002 CWA SECTION 303(d) LIST OF WATER QUALITY LIMITED SEGMENT SAN DIEGO REGIONAL WATER QUALITY CONTROL BOARD REGION TYPE NAME R Felicita Creek Approved by USE PA: July 2003 CALWATER WATERSHED POLLUTAJN T/STRESSO TMDL ESTIMATED PRIORITY SIZE AFFECTED PROPOSED TMDL COMPLETION 90523000 Total Dissolved Solids Low Agricultural Return Flows Urban Runoff/Storm Sewers Flow Regulation/Modification Unknown Nonpoint Source Unknown point source 0.92 Miles R Forester Creek 90712000 Fecal Coliform Medium Impairment Located at lower 1 mile. Urban Runoff/Storm Sewers Spills Unknown Nonpoint Source Unknown point source pH Low Impairment Located at upper 3 miles. Industrial Point Sources Habitat Modification Spills Unknown Nonpoint Source Unknown point source Total Dissolved Solids Low Impairment Located at lower I mile. Agricultural Return Flows Urban Runoff/Storm Sewers Flow Regulation/Modification Unknown Nonpoint Source Unknown point source 6.4 Miles 6.4 Miles 6.4 Miles R Green Valley Creek 90511000 Sulfates Low Urban Runoff/Storm Sewers Natural Sources Unknown Nonpoint Source Unknown point source 1.2 Miles L Guajome Lake 90311000 Eutrophic Low Nonpoint/Point Source 33 Acres Page 3 of 16 2002 CWA SECTION 303(d) LIST OF WATER QUALITY LIMITED SEGMENT SAM DIEGO REGIONAL WATER QUALITY CONTROL BOARD oApproved by VSEPA: July 2003 WATER WATERSHED POLLUTANT/STRESSOR POTENTIAL SOURCES TMDL PRIORITY ESTIMATED SIZE AFFECTED Hodges, Lake PROPOSED TMDL COMPLETION 90521000 Color Nitrogen Phosphorus Total Dissolved Solids Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source Agriculture Dairies Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source Agriculture Dairies Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source Agricultural Return Flows Urban Runoff/Storm Sewers Flow Regulation/Modification Natural Sources Unknown Nonpoint Source Unknown point source Low Low Low Low 1104 Acres 1104 Acres 1104 Acres 1104 Acres R Kit Carson Creek 90521000 Total Dissolved Solids Low Agricultural Return Flows Urban Runoff/Storm Sewers Flow Regulation/Modification Unknown Nonpoint Source Unknown point source 0.99 Miles 9 E Loma Alta Slough 90410000 Bacteria Indicators Nonpoint Source En trophic Nonpoint Source Low 8.2 Acres Low 8.2 Acres Page 4 of16 o o 2002 CWA SECTION 303(d) LIST OF WATER QUALITY LIMITED SEGMENT SAN DIEGO REGIONAL WATER QUALITY CONTROL BOARD July 2003 CALWATE WATERSHED POLLUTANT/STRESSOR POTENTIAL SOURCES TMDL ESTIMATED PROPOSED TMDL PRIORITY SIZE AFFECTED COMPLETION E Los Penasquitos Lagoon 90610000 Sedimentation/Siltation Low 469 Acres Nonpoint/Point Source B Mission Bay 90640000 Medium 2032 AcresBacteria Indicators Impairment located along entire bay shoreline. Nonpoint/Point Source Eutrophic Low 2032 Acres Estimated area of impairment of 0.5 acres located at mouth of Rose Creek and 0.5 acres located at mouth ofTecohte Creek. Nonpoint/Point Source Lead Low 2032 Acres Estimated area of impairment off). 5 acres located at mouth of Rose Creek and 0.5 acres located at mouth of Tecolote Creek. Nonpoint/Point Source R Murrieta Creek 90252000 Phosphorus Low 12 Miles Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source 9 C Pacific Ocean Shoreline, Aliso HSA 90113000 Bacteria Indicators Medium Impairment located at Laguna Beach at Lagunita Place/ Blue Lagoon Place, Aliso Beach. Nonpoint/Point Source 0.65 Miles C Pacific Ocean Shoreline, Buena Vista Creek HA 90421000 Bacteria Indicators Low 1.2 Miles Impairment located at Buena Vista Creek, Carlsbad City Beach at Carlsbad Village Drive, Carlsbad State Beach at Pine Avenue. Nonpoint/Point Source C Pacific Ocean Shoreline, Dana Point HSA 90114000 Bacteria Indicators Medium 2 Miles Impairment located at Aliso Beach at West Street, Aliso Beach at Table Rock Drive, 1000 Steps Beach at Pacific Coast Hwy (Hospital, 9th Ave), Salt Creek (large outlet), Salt Creek Beach at Salt Creek service road, Salt Creek Beach at Dana Strand Road. Nonpoint/Point Source Page 5 of 16 2002 CWA SECTION 303(d) LIST OF WATER QUALITY LIMITED SEGMENT SAIN DIEGO REGIONAL WATER QUALITY CONTROL BOARD July 2003 CALWATER WATERSHED POLLUTANT/STRESS TMDL ESTIMATED 1 RIOR1TV SIZE AFFECTED Pacific Ocean Shoreline, Escondido Creek HA 90461000 Bacteria Indicators Impairment located at San Elijo Lagoon outlet. Nonpoint/Point Source Low 0.44 Miles DL C Pacific Ocean Shoreline, Laguna Beach HSA 90112000 Bacteria Indicators Medium 1.8 Miles Impairment located at Main Laguna Beach, Laguna Beach at Ocean Avenue, Laguna Beach at Laguna Avenue, Laguna Beach at Cleo Street, Arch Cove at Bluebird Canyon Road, Laguna Beach at Dumond Drive. Nonpoint/Point Source C Pacific Ocean Shoreline, Loma Alta HA 90410000 Bacteria Indicators Impairment located at Loma Alta Creek Mouth. Nonpoint/Point Source Low 1.1 Miles C Pacific Ocean Shoreline, Lower San Juan HSA 90120000 Bacteria Indicators Medium 1.2 Miles Impairment located at North Beach Creek, San Juan Creek (large outlet), Capistrano Beach, South Capistrano Beach at Beach Road. Nonpoint/Point Source C Pacific Ocean Shoreline, Miramar Reservoir 90610000 HA Bacteria Indicators Low Impairment located at Torrey Pines State Beach at Del Mar (Anderson Canyon). Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source 0.39 Miles C Pacific Ocean Shoreline, San Clemente HA 90130000 Bacteria Indicators Medium 3.7 Miles Impairment located at Poche Beach (large outlet), Ole Hanson Beach Club Beach at Pico Drain, San Clemente City Beach at El Portal St. Stairs, San Clemente City Beach at Mariposa St., San Clemente City Beach at Linda Lane, San Clemente City Beach at South Linda Lane, San Clemente City Beach at Lifeguard Headquarters, Under San Clemente Municipal Pier, San Clemente City Beach at Trafalgar Canyon (Trafalgar Ln.), San Clemente State Beach at Riviera Beach, San Clemente State Beach at Cypress Shores. Nonpoint/Point Source 9 C Pacific Ocean Shoreline, San Diego HU 90711000 Bacteria Indicators Medium Impairment located at San Diego River Mouth (aka Dog Beach). Nonpoint/Point Source 0.37 Miles Page 6 of 16 2002 CWA SECTION 303(d) LIST OF WATER QUALITY LIMITED SEGMENT SAN DIEGO REGIONAL WATER QUALITY CONTROL BOARD July 2003 WATER ERSHED POLLUTAN17STRESSC TMDL ESTIMATED PROPOSED TMDL PRIORITY SIZE AFFECTED COMPLETION MDL I IN C Pacific Ocean Shoreline, San Diequito III 90511000 Bacteria Indicators Impairment located at San Dieguito Lagoon Mouth, So/ana Beach. Nonpoint/Point Source Low 0.86 Miles 9 C Pacific Ocean Shoreline, San Joaquin Hills HSA 90111000 Bacteria Indicators Low 0.63 Miles Impairment located at Cameo Cove at Irvine Cove Dr./Riviera Way, Heisler Park-North Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source 9 C Pacific Ocean Shoreline, San Luis Rey HU 90311000 Bacteria Indicators Impairment located at San Luis Rey River Mouth. Nonpoint/Point Source Low 0.49 Miles 9 C Pacific Ocean Shoreline, San Marcos HA 90451000 Bacteria Indicators Impairment located at Moonlight State Beach. Nonpoint/Point Source Low 0.5 Miles 9 C Pacific Ocean Shoreline, Scripps HA 90630000 Bacteria Indicators Medium 3.9 Miles Impairment located at La Jolla Shores Beach at El Paseo Grande, La Jo/la Shores Beach at Caminito Del Oro, La Jolla Shores Beach at Vallecitos, La Jolla Shores Beach atAve de la Playa, Casa Beach (Childrens Pool), South Casa Beach at Coast Blvd., Whispering Sands Beach at Ravina St., Windansea Beach at Vista de la Playa, Windansea Beach at Bonair St., Windansea Beach at Playa del Norte, Windansea Beach at Palomar Ave., Tourmaline Surf Park, Pacific Beach at Grand Ave. Nonpoint/Point Source 9 C Pacific Ocean Shoreline, Tijuana HU 91111000 Bacteria Indicators Low Impairment located from the border, extending north along the shore. Nonpoint/Point Source 3 Miles 9 R Pine Valley Creek (Upper)91141000 Enterococci Medium Grazing-Related Sources Concentrated Animal Feeding Operations (permitted, point source) Transient encampments 2.9 Miles Page 7 of 16 2002 CWA SECTION 303(d) LIST OF WATER QUALITY LIMITED SEGMENT SAN DIEGO REGIONAL WATER QUALITY CONTROL BOARD July 2003 CALWATER WATERSHED HO : AFFECTED COMPLETION R Prima Deshecha Creek 90130000 Phosphorus Turbidity Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source Low Low 1.2 Miles 1.2 Miles R Rainbow Creek 90222000 Nitrogen Phosphorus High Agricultural Return Flows Other Urban Runoff Nurseries Onsite Wastewater Systems (Septic Tanks) Nonpoint/Point Source High Agricultural Return Flows Other Urban Runoff Nurseries Onsite Wastewater Systems (Septic Tanks) Nonpoint/Point Source 5 Miles S Miles 2003 2003 9 B San Diego Bay Shoreline, 32nd St San Diego 90822000 Naval Station 9 B San Diego Bay Shoreline, between Sampson 90822000 and 28th Streets Benthic Community Effects Sediment Toxicity Copper Mercury PAHs Medium Nonpoint/Point Source Medium Nonpoint/Point Source High Nonpoint/Point Source High Nonpoint/Point Source High Nonpoint/Point Source 103 Acres 103 Acres 55 Acres 2003 55 Acres 2003 55 Acres 2003 Page 8 of 16 2002 CWA SECTION 303(d) LIST OF WATER QUALITY LIMITED SEGMENT SAN DIEGO REGIONAL WATER QUALITY CONTROL BOARD July 2003 REGION TYPE NAME CALWATER WATERSHED POLLUTA1ST/STRESSOR POTENTI SOURCES TMDL ESTIMATED I'ROPOSED TMDL PRIORITY PCBs Zinc Nonpoint/Point Source Nonpoint/Point Source High High 55 Acres 55 Acres 2003 2003 C San Diego Bay Shoreline, Chula Vista Marina 90912000 Bacteria Indicators Low Urban Runoff/Storm Sewers Marinas and Recreational Boating Boatyards Boat Discharges/Vessel Wastes 0.41 Miles 9 B San Diego Bay Shoreline, Downtown Anchorage 90821000 Benthic Community Effects Sediment Toxicity Nonpoint/Point Source Nonpoint/Point Source Medium Medium 9 B San Diego Bay Shoreline, near Coronado Bridge 90822000 7.4 Acres 7.4 Acres 9 C San Diego Bay Shoreline, G Street Pier 90821000 Bacteria Indicators 9 B San Diego Bay Shoreline, near Chollas Creek 90822000 Benthic Community Effects Sediment Toxicity Low Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source Medium Nonpoint/Point Source Medium Nonpoint/Point Source 0.42 Miles 15 Acres 15 Acres Benthic Community Effects Medium 37 Acres Nonpoint/Point Source Sediment Toxicity Medium 37 Acres Includes Crosby Street/Cesar Chavez Park area, that will receive additional monitoring. Nonpoint/Point Source Page 9 of 16 2002 CWA SECTION 303(d) LIST OF WATER QUALITY LIMITED SEGMENT SAN DIEGO REGIONAL WATER QUALITY CONTROL BOARD Approved by VSEPA: July 2003 REGION TYPEs*^22i 9 B San Diego Bay Shoreline, near sub base CALWATER WATERSHED POLLUTANT/STRESSOR POTENTIA SOURCES TMD1, ESTIMATED PRIORITY SIZE AFFECTED PROPOSED TMDI, COMPLETION 90810000 Benthic Community Effects Sediment Toxicity Nonpoint/Point Source Nonpoint/Point Source Medium Medium 16 Acres 16 Acres B San Diego Bay Shoreline, near Switzer Creek 90821000 Chlordane Medium Lindane Urban Runoff/Storm Sewers Other Boatyards Nonpoint/Point Source Urban Runoff/Storm Sewers Other Boatyards Nonpoint/Point Source Medium PAHs Medium San Diego Bay Shoreline, Seventh Street Channel 90831000 Benthic Community Effects Sediment Toxicity Nonpoint/Point Source Nonpoint/Point Source Medium Medium 5.5 Acres 5.5 Acres 5.5 Acres Urban Runoff/Storm Sewers Other Boatyards Nonpoint/Point Source 9 B San Diego Bay Shoreline, North of 24th Street Marine Terminal 90832000 Benthic Community Effects Sediment Toxicity Medium Nonpoint/Point Source Medium Nonpoint/Point Source 9.5 Acres 9.5 Acres 9 Acres 9 Acres Page 10 of 16 2002 CWA SECTION 303(d) LIST OF WATER QUALITY LIMITED SEGMENT SAN DIEGO REGIONAL WATER QUALITY CONTROL BOARD Approved by USEPA: July 2003 CALWATER REGION TYPE NAME WATERSHED POLLUTANT/STRESSOR POTENTlAi SOURCES TMDL ESTIMATED PRIORITY SIZE AFFECTED PROPOSED TMDL COMPLETION C San Diego Bay Shoreline, Shelter Island Shoreline Park 90810000 Bacteria Indicators Low Unknown Nonpoint Source Unknown point source 0.42 Miles C San Diego Bay Shoreline, Tidelands Park 91010000 Bacteria Indicators Low Unknown Nonpoint Source Unknown point source 0.38 Miles B San Diego Bay Shoreline, Vicinity of B St and Broadway Piers 90821000 Bacteria Indicators Low Estimated size of impairment is 0.4 miles around the shoreline of the bay. Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source Benthic Community Effects Medium Nonpoint/Point Source Sediment Toxicity Medium Nonpoint/Point Source 9 R San Diego River (Lower)90711000 Fecal Coliform Low Lower 6 miles. Urban Runoff/Storm Sewers Wastewater Nonpoint/Point Source Low Dissolved Oxygen Low Impairment transcends adjacent Calwater wtareshed 90712. Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source 9.9 Acres 9.9 Acres 9.9 Acres 9 B San Diego Bay, Shelter Island Yacht Basin 90810000 Copper, Dissolved High Nonpoint/Point Source 153 Acres 2003 12 Miles 12 Miles Page 11 of 16 2002 CWA SECTION 303(d) LIST OF WATER QUALITY LIMITED SEGMENT REGION TYPE NAME SAN DIEGO REGIONAL WATER QUALITY CONTROL BOARD July 2003 CALWATER WATERSHED POLLUTANT/STRESSOR POTENTIA SOURCES TMDL ESTIMATED PROPOSED TMDL PRIORITY SIZE AFFECTED COMPLETION Phosphorus Impairment transcends adjacent Calwater watershed 90712. Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source Total Dissolved Solids Impairment transcends adjacent Calwater watershed 90712. Urban Runoff/Storm Sewers Flow Regulation/Modification Natural Sources Unknown Nonpoint Source Unknown point source Low Low 12 Miles 12 Miles 9 E San Elijo Lagoon 90461000 Bacteria Indicators Low Estimated size of impairment is 150 acres. Nonpoint/Point Source Eutrophic Low Estimated size of impairment is 330 acres. Nonpoint/Point Source Sedimentation/Siltation Medium Estimated size of impairment is 150 acres. Nonpoint/Point Source 566 Acres 566 Acres 566 Acres 9 R San Juan Creek 90120000 Bacteria Indicators Medium Nonpoint/Point Source 1 Miles 9 E San Juan Creek (mouth)90120000 Bacteria Indicators Medium Nonpoint/Point Source 6.3 Acres 9 R San Luis Key River 90311000 Chloride Impairment located at lower 13 miles. Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source Low 19 Miles Page 12 of 16 ( 2002 CWA SECTION 303(d) LIST OF WATER QUALITY LIMITED SEGMENT SAN DIEGO REGIONAL WATER QUALITY CONTROL BOARD Approved by USEP.4: July 2003 CALWATER WATERSHED POLLUTANT/STRESSOR ESTIMATED PROPOSED TMDL PRIORITY SIZE AFFECTED COMPLETION Total Dissolved Solids Low Industrial Point Sources Agriculture-storm runoff Urban Runoff/Storm Sewers Surface Mining Flow Regulation/Modification Natural Sources Golf course activities Unknown Nonpoint Source Unknown point source 19 Miles 9 R Sandia Creek 9 R Segunda Deshecha Creek 90222000 Total Dissolved Solids Low Urban Runoff/Storm Sewers Flow Regulation/Modification Natural Sources Unknown Nonpoint Source Unknown point source 90130000 Phosphorus Turbidity Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source Construction/Land Development Urban Runoff/Storm Sewers Channelization Flow Regulation/Modification Unknown Nonpoint Source Unknown point source Low Low 1.5 Miles 9 E Santa Margarita Lagoon 90211000 Eutrophic Low Nonpoint/Point Source 9 R Santa Margarita River (Upper) 90222000 Phosphorus Low Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source 28 Acres 18 Miles 0.92 Miles 0.92 Miles Page 13 of 16 2002 CWA SECTION 303(d) LIST OF WATER QUALITY LIMITED SEGMENTv ' ^ July 2003 SAN DIEGO REGIONAL WATER QUALITY CONTROL BOARD CALWATER REGION TYPE NAME WATERSHED POLLUTANT/STRESSOR 9 L Sutherland Reservoir 90553000 Color 9 R Tecolote Creek 90650000 Bacteria Indicators Cadmium Copper Lead Toxicity Zinc 9 R Tijuana River 91111000 Bacteria Indicators Eutrophic Low Dissolved Oxygen Pesticides Solids Synthetic Organics Trace Elements Trash POTENTIAL SOURCES Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source Nonpoint/Point Source Nonpoint/Point Source Nonpoint/Point Source Nonpoint/Point Source Nonpoint/Point Source Nonpoint/Point Source Nonpoint/Point Source Nonpoint/Point Source Nonpoint/Point Source Nonpoint/Point Source Nonpoint/Point Source Nonpoint/Point Source Nonpoint/Point Source Nonpoint/Point Source TMDL ESTIMATED PROPOSED TMDL j PRIORITY SIZE AFFECTED COMPLETION | Low Medium Low Low Low Low Low Low Low Low Low Low Low Low Low 561 6.6 6.6 6.6 6.6 6.6 6.6 5.8 5.8 5.8 5.8 5.8 5.8 5.8 5.8 Acres Miles Miles Miles Miles Miles Miles Miles Miles Miles Miles Miles Miles Miles Miles Page 14 of 16 2002 CWA SECTION 303(d) LIST OF WATER QUALITY LIMITED SEGMENT SAN DIEGO REGIONAL WATER QUALITY CONTROL BOARD Approved by USEPA: July 2003 WATERSHED POLLUTANT/STRESSO 9 E Tijuana River Estuary TMDL ESTIMATED PRIORITY SIZE AFFECTED PROPOSED TMDL I COMPLETION 91111000 Bacteria Indicators Low Estimated size of impairment is ISO acres. Nonpoint/Point Source Eutrophic Low Estimated size of impairment is 1 acre. Nonpoint/Point Source Lead Low Estimated size of impairment is I acre. Nonpoint/Point Source Low Dissolved Oxygen Low Urban Runoff/Storm Sewers Wastewater Unknown Nonpoint Source Unknown point source Nickel Low Estimated size of impairment is 1 acre. Nonpoint/Point Source Pesticides Low Estimated size of impairment is 1 acre. Nonpoint/Point Source Thallium Low Estimated size of impairment is I acre. Nonpoint/Point Source Trash Low Estimated size of impairment is I acre. Nonpoint/Point Source 1319 Acres 1319 Acres 1319 Acres 1319 Acres 1319 Acres 1319 Acres 1319 Acres 1319 Acres Page IS of 16 2002 CWA SECTION 303(d) LIST OF WATER QUALITY LIMITED SEGMENT SAN DIEGO REGIONAL WATER QUALITY CONTROL BOARD oApproved by USEPA: Julv 2003 REGION TYPE NAME CALWATER WATERSHED POLLUTANT/STRESSOR TMDL ESTIMATED PROPOSED TMIH. PRIORITY SIZE AFFECTED COMPLETION REGIONAL WATER QUALITY CONTROL BOARDS 1 North Coast 2 San Francisco Bay 3 Central Coast 4 Los Angeles 5 Central Valley 6 Lahontan 7 Colorado River Basin 8 Santa Ana 9 San Diego WATER BODY TYPE B = Bays and Harbors C = Coastal Shorelines/Beaches E = Estuaries L = Lakes/Reserviors R = Rivers and Streams S = Saline Lakes T = Wetlands, Tidal W= Wetlands, Freshwater CALWATER WATERSHED "Calwater Watershed" is the State Water Resources Control Board hydrological subunit area or an even smaller area delineation. GROUP A PESTICIDES OR CHEM A aldrin, dieldrin, chlordane, endrin, heptachlor, heptachlor epoxide, hexachlorocyclohexane (including lindane), endosulfan, and toxaphene Page 16 of 16 APPENDIX G . 48".[ ACCESS WAY 17.0' ]Z£< 13.0' TRASH BIN (3 CY TYPICAL) 6"0 CONCRETE RLLED IRON POST, ^ r~r~^i—r^^Ti rJ I RECYCLABLE i L_ jBINt j1 ' Tr__( — i rr-i TYPICAL) qin / .fl. -I I \ / M ROLL OUTilii OPTIONAL RECYCLABLE f „ /DIRECTION ] [1 j CONTAINERS INSTEAD . X-TE FRAMtNJj ]]'Uj OF.W-4 rtQH iL—|-T"AND MATERIALS--!-jULL--" I s 10.5% (TYP.) • REFUSE TRUCK LOADING APPROACH •« 0.5% (TYP.) FERROUS METAL 12-X12" ,REA DRAIN (TYP.) LEVEL LOADING AREA 1 (CONCRETE) DRAIN AWAY (TYP.) TYPE A - DRIVE AND LOAD FRONT APPROACH FILLED BLOCK WALL PER CITY OF CARLSBAD MASONRY FENCE STRIP (TYP.) WHERE APPLICABLE 3" PROTECTION POST (MOD. W-16) YCONCRETE CURB GATE GATE CANE SECURING BOLT (TYP.) -f—0.5% (TYP.) REFUSE TRUCK LOADING APPROACH LEVEL LOADING AREAI (CONCRETE) mto *l 65" 12" r^t]L T1"1"i-1 16"i it) 4" ^hzk-^1 15.0'(MIN.) LEVEL . CLEAR OVERHEAD - TO 25.0 FT.(MIN.) HEIGHT 7.5"(MIN.) 30- CONCRETE T y\ V24"x8' FOUNDATION TYPE B - DRIVE AND LOAD SIDE APPROACH CLEAR OVERHEAD.TO. HEIGHT 4" AC OVER 6" CLASS H A.B. (MIN.) 13.0' DRAIN TO BMP (TYP.) SECTION A-A (TYP.) (TYP.) SECTION B-B SHEET 1 OF 2 REV.APPROVED DATE CITY OF CARLSBAD REFUSE BIN ENCLOSURE FOR 3 CUBIC YARDS BINS 6-04 CITY ENGINEER DATE SUPPLEMENTAL STANDARD NO. NOTES: 1. LOCATION OF REFUSE BIN ENCLOSURES SHALL BE APPROVED BY THE PLANNING DIRECTOR AND THE CITY ENGINEER. ENCLOSURE SHALL BE OF SIMILAR COLORS AND/OR MATERIALS AS THE PROJECT TO THE SATISFACTION OF THE PLANNING DIRECTOR. 2. THE ENCLOSURE SLAB AND LOADING AREA SHALL BE LEVEL IN ORDER TO FACILITATE THE ROLLING OF BINS FOR LOADING POSITIONING. 3. GATES SHALL BE MOUNTED SO THAT THEY SWING FULLY OPEN WITH NO PROTRUSION INTO THE PATH OF THE BIN. THE GATES SHALL HAVE CHAINS, HOOKS OR PIN STOPS AT THEIR FULL OPEN POSITION TO HOLD THEM OPEN. 4. ALL GATE CONNECTION LATCHES, SECURING BOLTS, FRAMING, AND HINGES SHALL BE HEAVY DUTY TYPE AND PAINTED OR TREATED AGAINST CORROSION. 5. GATE MATERIALS TO BE APPROVED BY PLANNING DIRECTOR. 6. POSITIVE DRAINAGE AWAY FROM THE ENCLOSURE AND LOADING AREAS SHALL BE PROVIDED AND MAINTAINED. 7. ALTERNATIVE CONFIGURATION AND LOCATION OF THE ACCESS WAY MAY BE ACCEPTABLE ON A CASE BY CASE BASIS PROVIDED NO PORTION OF THE TRASH BINS ARE DIRECTLY VISIBLE TO THE PUBLIC. 8. LOADING AND ENCLOSURE AREA DRAINAGE SHALL BE INDEPENDENT AND DRAINED TOWARDS AN APPROVED SITE BMP. 9. DEVELOPMENT PROJECTS SHALL INCORPORATE THE REQUIREMENTS OF THE "MODEL ORDINANCE OF THE CALIFORNIA INTEGRATED WASTE MANAGEMENT BOARD RELATING TO AREAS FOR COLLECTING AND LOADING RECYCLABLE MATERIALS". 10. AREAS FOR RECYCLING SHALL BE ADEQUATE IN CAPACITY, NUMBER AND DISTRIBUTION TO SERVE THE DEVELOPMENT WHERE THE PROJECT OCCURS. 11. RECYCLING AREAS SHALL BE SECURED TO PREVENT THE THEFT OF RECYCLABLE MATERIALS BY UNAUTHORIZED PERSONS WHILE ALLOWING AUTHORIZED PERSONS ACCESS FOR DISPOSAL OF MATERIALS. 12. RECYCLING AREAS OR THE BINS AND CONTAINERS PLACED THEREIN MUST PROVIDE PROTECTION AGAINST SEVERE ENVIRONMENTAL CONDITIONS WHICH MIGHT RENDER THE COLLECTED MATERIALS UNMARKETABLE. 13. A SIGN CLEARLY IDENTIFYING ALL RECYCLING AND SOLID WASTE COLLECTION AND LOADING AREAS AND THE MATERIALS ACCEPTED THEREIN SHALL BE POSTED ADJACENT TO ALL POINTS OF ACCESS TO THE RECYCLING AREAS. 14. EACH RECYCLING AREA WITHIN A MULTI-FAMILY RESIDENTIAL DEVELOPMENT SHALL BE NO GREATER THAN 250 FEET FROM EACH LIVING UNIT. SHEET 2 OF 2 JEV.APPROVED DATE CITY OF CARLSBAD REFUSE BIN ENCLOSURE FOR 3 CUBIC YARDS BINS &-~*~6-04 CITY ENGINEER DATE SUPPLEMENTAL STANDARD NO. Site Design & Landscape Planning SD-10 Design Objectives J Maximize Infiltration S Provide Retention / Slow Runoff / Minimize Impervious Land Coverage Prohibit Dumping of Improper Materials Contain Pollutants Collect and Convey Description Each project site possesses unique topographic, hydrologic, and vegetative features, some of which are more suitable for development than others. Integrating and incorporating appropriate landscape planning methodologies into the project design is the most effective action that can be done to minimize surface and groundwater contamination from stormwater. Approach Landscape planning should couple consideration of land suitability for urban uses with consideration of community goals and projected growth. Project plan designs should conserve natural areas to the extent possible, maximize natural water storage and infiltration opportunities, and protect slopes and channels. Suitable Applications Appropriate applications include residential, commercial and industrial areas planned for development or redevelopment. Design Considerations Design requirements for site design and landscapes planning should conform to applicable standards and specifications of agencies with jurisdiction and be consistent with applicable General Plan and Local Area Plan policies. Stormwater Quality Association January 2003 California Stormwater BMP Handbook 1 of 4 New Development and Redevelopment www.cabmphandbooks.com SD-10 Site Design & Landscape Planning Designing New Installations Begin the development of a plan for the landscape unit with attention to the following general principles: • Formulate the plan on the basis of clearly articulated community goals. Carefully identify conflicts and choices between retaining and protecting desired resources and community growth. • Map and assess land suitability for urban uses. Include the following landscape features in the assessment: wooded land, open unwooded land, steep slopes, erosion-prone soils, foundation suitability, soil suitability for waste disposal, aquifers, aquifer recharge areas, wetlands, floodplains, surface waters, agricultural lands, and various categories of urban land use. When appropriate, the assessment can highlight outstanding local or regional resources that the community determines should be protected (e.g., a scenic area, recreational area, threatened species habitat, farmland, fish run). Mapping and assessment should recognize not only these resources but also additional areas needed for their sustenance. Project plan designs should conserve natural areas to the extent possible, maximize natural water storage and infiltration opportunities, and protect slopes and channels. Conserve Natural Areas during Landscape Planning If applicable, the following items are required and must be implemented in the site layout during the subdivision design and approval process, consistent with applicable General Plan and Local Area Plan policies: • Cluster development on least-sensitive portions of a site while leaving the remaining land in a natural undisturbed condition. • Limit clearing and grading of native vegetation at a site to the minimum amount needed to build lots, allow access, and provide fire protection. • Maximize trees and other vegetation at each site by planting additional vegetation, clustering tree areas, and promoting the use of native and/or drought tolerant plants. • Promote natural vegetation by using parking lot islands and other landscaped areas. • Preserve riparian areas and wetlands. Maximize Natural Water Storage and Infiltration Opportunities Within the Landscape Unit • Promote the conservation of forest cover. Building on land that is already deforested affects basin hydrology to a lesser extent than converting forested land. Loss of forest cover reduces interception storage, detention in the organic forest floor layer, and water losses by evapotranspiration, resulting in large peak runoff increases and either their negative effects or the expense of countering them with structural solutions. • Maintain natural storage reservoirs and drainage corridors, including depressions, areas of permeable soils, swales, and intermittent streams. Develop and implement policies and 2 of 4 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Site Design & Landscape Planning SD-10 regulations to discourage the clearing, filling, and channelization of these features. Utilize them in drainage networks in preference to pipes, culverts, and engineered ditches. • Evaluating infiltration opportunities by referring to the stormwater management manual for the jurisdiction and pay particular attention to the selection criteria for avoiding groundwater contamination, poor soils, and hydrogeological conditions that cause these facilities to fail. If necessary, locate developments with large amounts of impervious surfaces or a potential to produce relatively contaminated runoff away from groundwater recharge areas. Protection of Slopes and Channels during Landscape Design m Convey runoff safely from the tops of slopes. • Avoid disturbing steep or unstable slopes. • Avoid disturbing natural channels. • Stabilize disturbed slopes as quickly as possible. • Vegetate slopes with native or drought tolerant vegetation. • Control and treat flows in landscaping and/or other controls prior to reaching existing natural drainage systems. • Stabilize temporary and permanent channel crossings as quickly as possible, and ensure that increases in run-off velocity and frequency caused by the project do not erode the channel. • Install energy dissipaters, such as riprap, at the outlets of new storm drains, culverts, conduits, or channels that enter unlined channels in accordance with applicable specifications to minimize erosion. Energy dissipaters shall be installed in such a way as to minimize impacts to receiving waters. • Line on-site conveyance channels where appropriate, to reduce erosion caused by increased flow velocity due to increases in tributary impervious area. The first choice for linings should be grass or some other vegetative surface, since these materials not only reduce runoff velocities, but also provide water quality benefits from filtration and infiltration. If velocities in the channel are high enough to erode grass or other vegetative linings, riprap, concrete, soil cement, or geo-grid stabilization are other alternatives. • Consider other design principles that are comparable and equally effective. Redeveloping Existing Installations Various jurisdictional stormwater management and mitigation plans (SUSMP, WQMP, etc.) define "redevelopment" in terms of amounts of additional impervious area, increases in gross floor area and/or exterior construction, and land disturbing activities with structural or impervious surfaces. The definition of " redevelopment" must be consulted to determine whether or not the requirements for new development apply to areas intended for redevelopment. If the definition applies, the steps outlined under "designing new installations" above should be followed. January 2003 California Stormwater BMP Handbook 3 of 4 New Development and Redevelopment www.cabmphandbooks.com SD-10 Site Design & Landscape Planning Redevelopment may present significant opportunity to add features which had not previously been implemented. Examples include incorporation of depressions, areas of permeable soils, and swales in newly redeveloped areas. While some site constraints may exist due to the status of already existing infrastructure, opportunities should not be missed to maximize infiltration, slow runoff, reduce impervious areas, disconnect directly connected impervious areas. Other Resources A Manual for the Standard Urban Stormwater Mitigation Plan (SUSMP), Los Angeles County Department of Public Works, May 2002. Stormwater Management Manual for Western Washington, Washington State Department of Ecology, August 2001. Model Standard Urban Storm Water Mitigation Plan (SUSMP) for San Diego County, Port of San Diego, and Cities in San Diego County, February 14, 2002. Model Water Quality Management Plan (WQMP) for County of Orange, Orange County Flood Control District, and the Incorporated Cities of Orange County, Draft February 2003. Ventura Countywide Technical Guidance Manual for Stormwater Quality Control Measures, July 2002. 4 of 4 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Roof Runoff Controls SD-11 Design Objectives J Maximize Infiltration J Provide Retention •/ Slow Runoff Minimize Impervious Land Coverage Prohibit Dumping of Improper Materials y Contain Pollutants Collect and Convey Rain Garden Description Various roof runoff controls are available to address stormwater that drains off rooftops. The objective is to reduce the total volume and rate of runoff from individual lots, and retain the pollutants on site that maybe picked up from roofing materials and atmospheric deposition. Roof runoff controls consist of directing the roof runoff away from paved areas and mitigating flow to the storm drain system through one of several general approaches: cisterns or rain barrels; dry wells or infiltration trenches; pop-up emitters, and foundation planting. The first three approaches require the roof runoff to be contained in a gutter and downspout system. Foundation planting provides a vegetated strip under the drip line of the roof. Approach Design of individual lots for single-family homes as well as lots for higher density residential and commercial structures should consider site design provisions for containing and infiltrating roof runoff or directing roof runoff to vegetative swales or buffer areas. Retained water can be reused for watering gardens, lawns, and trees. Benefits to the environment include reduced demand for potable water used for irrigation, improved stormwater quality, increased groundwater recharge, decreased runoff volume and peak flows, and decreased flooding potential. Suitable Applications Appropriate applications include residential, commercial and industrial areas planned for development or redevelopment. Design Considerations Designing New Installations Cisterns or Rain Barrels One method of addressing roof runoff is to direct roof downspouts to cisterns or rain barrels. A cistern is an above ground storage vessel with either a manually operated valve or a permanently open outlet. Roof runoff is temporarily stored and then released for irrigation or infiltration between storms. The number of rain iJfilA California Stormwater Quality Association January 2003 California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbook.com 1 of 3 SD-11 Roof Runoff Controls barrels needed is a function of the rooftop area. Some low impact developers recommend that every house have at least 2 rain barrels, with a minimum storage capacity of 1000 liters. Roof barrels serve several purposes including mitigating the first flush from the roof which has a high volume, amount of contaminants, and thermal load. Several types of rain barrels are commercially available. Consideration must be given to selecting rain barrels that are vector proof and childproof. In addition, some barrels are designed with a bypass valve that filters out grit and other contaminants and routes overflow to a soak-away pit or rain garden. If the cistern has an operable valve, the valve can be closed to store stormwater for irrigation or infiltration between storms. This system requires continual monitoring by the resident or grounds crews, but provides greater flexibility in water storage and metering. If a cistern is provided with an operable valve and water is stored inside for long periods, the cistern must be covered to prevent mosquitoes from breeding. A cistern system with a permanently open outlet can also provide for metering stormwater runoff. If the cistern outlet is significantly smaller than the size of the downspout inlet (say lfa to ¥2 inch diameter), runoff will build up inside the cistern during storms, and will empty out slowly after peak intensities subside. This is a feasible way to mitigate the peak flow increases caused by rooftop impervious land coverage, especially for the frequent, small storms. Dry wells and Infiltration Trenches Roof downspouts can be directed to dry wells or infiltration trenches. A dry well is constructed by excavating a hole in the ground and filling it with an open graded aggregate, and allowing the water to fill the dry well and infiltrate after the storm event. An underground connection from the downspout conveys water into the dry well, allowing it to be stored in the voids. To minimize sedimentation from lateral soil movement, the sides and top of the stone storage matrix can be wrapped in a permeable filter fabric, though the bottom may remain open. A perforated observation pipe can be inserted vertically into the dry well to allow for inspection and maintenance. In practice, dry wells receiving runoff from single roof downspouts have been successful over long periods because they contain very little sediment. They must be sized according to the amount of rooftop runoff received, but are typically 4 to 5 feet square, and 2 to 3 feet deep, with a minimum of i-foot soil cover over the top (maximum depth of 10 feet). To protect the foundation, dry wells must be set away from the building at least 10 feet. They must be installed in solids that accommodate infiltration. In poorly drained soils, dry wells have very limited feasibility. Infiltration trenches function in a similar manner and would be particularly effective for larger roof areas. An infiltration trench is a long, narrow, rock-filled trench with no outlet that receives stormwater runoff. These are described under Treatment Controls. Pop-up Drainage Emitter Roof downspouts can be directed to an underground pipe that daylights some distance from the building foundation, releasing the roof runoff through a pop-up emitter. Similar to a pop-up irrigation head, the emitter only opens when there is flow from the roof. The emitter remains flush to the ground during dry periods, for ease of lawn or landscape maintenance. 2 of 3 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbook.com Roof Runoff Controls SD-11 Foundation Planting Landscape planting can be provided around the base to allow increased opportunities for stormwater infiltration and protect the soil from erosion caused by concentrated sheet flow coming off the roof. Foundation plantings can reduce the physical impact of water on the soil and provide a subsurface matrix of roots that encourage infiltration. These plantings must be sturdy enough to tolerate the heavy runoff sheet flows, and periodic soil saturation. Redeveloping Existing Installations Various jurisdictional stormwater management and mitigation plans (SUSMP, WQMP, etc.) define "redevelopment" in terms of amounts of additional impervious area, increases in gross floor area and/or exterior construction, and land disturbing activities with structural or impervious surfaces. The definition of " redevelopment" must be consulted to determine whether or not the requirements for new development apply to areas intended for redevelopment. If the definition applies, the steps outlined under "designing new installations" above should be followed. Supplemental Information Examples m City of Ottawa's Water Links Surface -Water Quality Protection Program • City of Toronto Downspout Disconnection Program • City of Boston, MA, Rain Barrel Demonstration Program Other Resources Hager, Marty Catherine, Stormwater, "Low-Impact Development", January/February 2003. www.stormh2o.com Low Impact Urban Design Tools, Low Impact Development Design Center, Beltsville, MD. www.lid-stormwater.net Start at the Source, Bay Area Stormwater Management Agencies Association, 1999 Edition January 2003 California Stormwater BMP Handbook 3 of 3 New Development and Redevelopment www.cabmphandbook.com Efficient Irrigation SD-12 Design Objectives J Maximize Infiltration J Provide Retention y Slow Runoff Minimize Impervious Land Coverage Prohibit Dumping of Improper Materials Contain Pollutants Collect and Convey Description ~ —— ——- — Irrigation water provided to landscaped areas may result in excess irrigation water being conveyed into stormwater drainage systems. Approach Project plan designs for development and redevelopment should include application methods of irrigation water that minimize runoff of excess irrigation water into the stormwater conveyance system. Suitable Applications Appropriate applications include residential, commercial and industrial areas planned for development or redevelopment. (Detached residential single-family homes are typically excluded from this requirement.) Design Considerations Designing New Installations The following methods to reduce excessive irrigation runoff should be considered, and incorporated and implemented where determined applicable and feasible by the Permittee: • Employ rain-triggered shutoff devices to prevent irrigation after precipitation. • Design irrigation systems to each landscape area's specific water requirements. • Include design featuring flow reducers or shutoff valves triggered by a pressure drop to control water loss in the event of broken sprinkler heads or lines. • Implement landscape plans consistent with County or City water conservation resolutions, which may include provision of water sensors, programmable irrigation times (for short cycles), etc. fiJji&C1 M, S Q A Stormwater Quality Association January 2003 California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbooks.com 1 of 2 SD-12 Efficient Irrigation • Design timing and application methods of irrigation water to minimize the runoff of excess irrigation water into the storm water drainage system. • Group plants with similar water requirements in order to reduce excess irrigation runoff and promote surface filtration. Choose plants with low irrigation requirements (for example, native or drought tolerant species). Consider design features such as: Using mulches (such as wood chips or bar) in planter areas without ground cover to minimize sediment in runoff Installing appropriate plant materials for the location, in accordance with amount of sunlight and climate, and use native plant materials where possible and/or as recommended by the landscape architect Leaving a vegetative barrier along the property boundary and interior watercourses, to act as a pollutant filter, where appropriate and feasible - Choosing plants that minimize or eliminate the use of fertilizer or pesticides to sustain growth • Employ other comparable, equally effective methods to reduce irrigation water runoff. Redeveloping Existing Installations Various jurisdictional stormwater management and mitigation plans (SUSMP, WQMP, etc.) define "redevelopment" in terms of amounts of additional impervious area, increases in gross floor area and/or exterior construction, and land disturbing activities with structural or impervious surfaces. The definition of " redevelopment" must be consulted to determine whether or not the requirements for new development apply to areas intended for redevelopment. If the definition applies, the steps outlined under "designing new installations" above should be followed. Other Resources A Manual for the Standard Urban Stormwater Mitigation Plan (SUSMP), Los Angeles County Department of Public Works, May 2002. Model Standard Urban Storm Water Mitigation Plan (SUSMP) for San Diego County, Port of San Diego, and Cities in San Diego County, February 14, 2002. Model Water Quality Management Plan (WQMP) for County of Orange, Orange County Flood Control District, and the Incorporated Cities of Orange County, Draft February 2003. Ventura Countywide Technical Guidance Manual for Stormwater Quality Control Measures, July 2002. 2 of 2 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Storm Drain Signage SD-13 Design Objectives Maximize Infiltration Provide Retention Slow Runoff Minimize Impervious Land Coverage y Prohibit Dumping of Improper Materials Contain Pollutants Collect and Convey Description Waste materials dumped into storm drain inlets can have severe impacts on receiving and ground waters. Posting notices regarding discharge prohibitions at storm drain inlets can prevent waste dumping. Storm drain signs and stencils are highly visible source controls that are typically placed directly adjacent to storm drain inlets. Approach The stencil or affixed sign contains a brief statement that prohibits dumping of improper materials into the urban runoff conveyance system. Storm drain messages have become a popular method of alerting the public about the effects of and the prohibitions against waste disposal. Suitable Applications Stencils and signs alert the public to the destination of pollutants discharged to the storm drain. Signs are appropriate in residential, commercial, and industrial areas, as well as any other area where contributions or dumping to storm drains is likely. Design Considerations Storm drain message markers or placards are recommended at all storm drain inlets within the boundary of a development project. The marker should be placed in clear sight facing toward anyone approaching the inlet from either side. All storm drain inlet locations should be identified on the development site map. Designing New Installations The following methods should be considered for inclusion in the project design and show on project plans: Provide stenciling or labeling of all storm drain inlets and catch basins, constructed or modified, within the project area with prohibitive language. Examples include "NO DUMPING - SQA California Stormwater Quality Association January 2003 California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbooks.com 1 of 2 ^ SD-13 Storm Drain Signage DRAINS TO OCEAN" and/or other graphical icons to discourage illegal dumping. • Post signs with prohibitive language and/or graphical icons, which prohibit illegal dumping at public access points along channels and creeks within the project area. Note - Some local agencies have approved specific signage and/or storm drain message placards for use. Consult local agency stormwater staff to determine specific requirements for placard types and methods of application. Redeveloping Existing Installations Various jurisdictional stormwater management and mitigation plans (SUSMP, WQMP, etc.) define "redevelopment" in terms of amounts of additional impervious area, increases in gross floor area and/or exterior construction, and land disturbing activities with structural or impervious surfaces. If the project meets the definition of "redevelopment", then the requirements stated under " designing new installations" above should be included in all project design plans. Additional Information Maintenance Considerations m Legibility of markers and signs should be maintained. If required by the agency with jurisdiction over the project, the owner/operator or homeowner's association should enter into a maintenance agreement with the agency or record a deed restriction upon the property title to maintain the legibility of placards or signs. Placement • Signage on top of curbs tends to weather and fade. • Signage on face of curbs tends to be worn by contact with vehicle tires and sweeper brooms. Supplemental Information Examples • Most MS4 programs have storm drain signage programs. Some MS4 programs will provide stencils, or arrange for volunteers to stencil storm drains as part of their outreach program. Other Resources A Manual for the Standard Urban Stormwater Mitigation Plan (SUSMP), Los Angeles County Department of Public Works, May 2002. Model Standard Urban Storm Water Mitigation Plan (SUSMP) for San Diego County, Port of San Diego, and Cities in San Diego County, February 14, 2002. Model Water Quality Management Plan (WQMP) for County of Orange, Orange County Flood Control District, and the Incorporated Cities of Orange County, Draft February 2003. Ventura Countywide Technical Guidance Manual for Stormwater Quality Control Measures, July 2002. 2 of 2 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Pervious Pavements SD-20 Design Objectives J Maximize Infiltration J Provide Retention J Slow Runoff J Minimize Impervious Land Coverage Prohibit Dumping of Improper Materials Contain Pollutants Collect and Convey Description Pervious paving is used for light vehicle loading in parking areas. The term describes a system comprising a load-bearing, durable surface together with an underlying layered structure that temporarily stores water prior to infiltration or drainage to a controlled outlet. The surface can itself be porous such that water infiltrates across the entire surface of the material (e.g., grass and gravel surfaces, porous concrete and porous asphalt), or can be built up of impermeable blocks separated by spaces and joints, through which the water can drain. This latter system is termed 'permeable' paving. Advantages of pervious pavements is that they reduce runoff volume while providing treatment, and are unobtrusive resulting in a high level of acceptability. Approach Attenuation of flow is provided by the storage within the underlying structure or sub base, together with appropriate flow controls. An underlying geotextile may permit groundwater recharge, thus contributing to the restoration of the natural water cycle. Alternatively, where infiltration is inappropriate (e.g., if the groundwater vulnerability is high, or the soil type is unsuitable), the surface can be constructed above an impermeable membrane. The system offers a valuable solution for drainage of spatially constrained urban areas. Significant attenuation and improvement in water quality can be achieved by permeable pavements, whichever method is used. The surface and subsurface infrastructure can remove both the soluble and fine particulate pollutants that occur within urban runoff. Roof water can be piped into the storage area directly, adding areas from which the flow can be attenuated. Also, within lined systems, there is the opportunity for stored runoff to be piped out for reuse. Suitable Applications Residential, commercial and industrial applications are possible. The use of permeable pavement may be restricted in cold regions, arid regions or regions with high wind erosion. There are some specific disadvantages associated with permeable pavement, which are as follows: • Permeable pavement can become clogged if improperly installed or maintained. However, this is countered by the ease with which small areas of paving can be cleaned or replaced when blocked or damaged. January 2003 California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbooks.com 1 of 10 SD-20 Pervious Pavements • Their application should be limited to highways with low traffic volumes, axle loads and speeds (less than 30 mph limit), car parking areas and other lightly trafficked or non- trafficked areas. Permeable surfaces are currently not considered suitable for adoptable roads due to the risks associated with failure on high speed roads, the safety implications of ponding, and disruption arising from reconstruction. • When using un-lined, infiltration systems, there is some risk of contaminating groundwater, depending on soil conditions and aquifer susceptibility. However, this risk is likely to be small because the areas drained tend to have inherently low pollutant loadings. • The use of permeable pavement is restricted to gentle slopes. • Porous block paving has a higher risk of abrasion and damage than solid blocks. Design Considerations Designing New Installations If the grades, subsoils, drainage characteristics, and groundwater conditions are suitable, permeable paving may be substituted for conventional pavement on parking areas, cul de sacs and other areas with light traffic. Slopes should be flat or very gentle. Scottish experience has shown that permeable paving systems can be installed in a wide range of ground conditions, and the flow attenuation performance is excellent even when the systems are lined. The suitability of a pervious system at a particular pavement site will, however, depend on the loading criteria required of the pavement. Where the system is to be used for infiltrating drainage waters into the ground, the vulnerability of local groundwater sources to pollution from the site should be low, and the seasonal high water table should be at least 4 feet below the surface. Ideally, the pervious surface should be horizontal in order to intercept local rainfall at source. On sloping sites, pervious surfaces may be terraced to accommodate differences in levels. Design Guidelines The design of each layer of the pavement must be determined by the likely traffic loadings and their required operational life. To provide satisfactory performance, the following criteria should be considered: • The subgrade should be able to sustain traffic loading without excessive deformation. • The granular capping and sub-base layers should give sufficient load-bearing to provide an adequate construction platform and base for the overlying pavement layers. • The pavement materials should not crack of suffer excessive rutting under the influence of traffic. This is controlled by the horizontal tensile stress at the base of these layers. There is no current structural design method specifically for pervious pavements. Allowances should be considered the following factors in the design and specification of materials: 2 of 10 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Pervious Pavements SD-20 • Pervious pavements use materials with high permeability and void space. All the current UK pavement design methods are based on the use of conventional materials that are dense and relatively impermeable. The stiffness of the materials must therefore be assessed. • Water is present within the construction and can soften and weaken materials, and this must be allowed for. • Existing design methods assume full friction between layers. Any geotextiles or geomembranes must be carefully specified to minimize loss of friction between layers. • Porous asphalt loses adhesion and becomes brittle as air passes through the voids. Its durability is therefore lower than conventional materials. The single sized grading of materials used means that care should be taken to ensure that loss of finer particles between unbound layers does not occur. Positioning a geotextile near the surface of the pervious construction should enable pollutants to be trapped and retained close to the surface of the construction. This has both advantages and disadvantages. The main disadvantage is that the filtering of sediments and their associated pollutants at this level may hamper percolation of waters and can eventually lead to surface ponding. One advantage is that even if eventual maintenance is required to reinstate infiltration, only a limited amount of the construction needs to be disturbed, since the sub-base below the geotextile is protected. In addition, the pollutant concentration at a high level in the structure allows for its release over time. It is slowly transported in the stormwater to lower levels where chemical and biological processes may be operating to retain or degrade pollutants. The design should ensure that sufficient void space exists for the storage of sediments to limit the period between remedial works. • Pervious pavements require a single size grading to give open voids. The choice of materials is therefore a compromise between stiffness, permeability and storage capacity. • Because the sub-base and capping will be in contact with water for a large part of the time, the strength and durability of the aggregate particles when saturated and subjected to wetting and drying should be assessed. • A uniformly graded single size material cannot be compacted and is liable to move when construction traffic passes over it. This effect can be reduced by the use of angular crushed rock material with a high surface friction. In pollution control terms, these layers represent the site of long term chemical and biological pollutant retention and degradation processes. The construction materials should be selected, in addition to their structural strength properties, for their ability to sustain such processes. In general, this means that materials should create neutral or slightly alkaline conditions and they should provide favorable sites for colonization by microbial populations. Construction/Inspection Considerations m Permeable surfaces can be laid without cross-falls or longitudinal gradients. • The blocks should be lain level January 2003 California Stormwater BMP Handbook 3 of 10 New Development and Redevelopment www.cabmphandbooks.com "*«*«»" SD-20 Pervious Pavements • They should not be used for storage of site materials, unless the surface is well protected from deposition of silt and other spillages. • The pavement should be constructed in a single operation, as one of the last items to be built, on a development site. Landscape development should be completed before pavement construction to avoid contamination by silt or soil from this source. • Surfaces draining to the pavement should be stabilized before construction of the pavement. • Inappropriate construction equipment should be kept away from the pavement to prevent damage to the surface, sub-base or sub-grade. Maintenance Requirements The maintenance requirements of a pervious surface should be reviewed at the time of design and should be clearly specified. Maintenance is required to prevent clogging of the pervious surface. The factors to be considered when defining maintenance requirements must include: • Type of use • Ownership • Level of trafficking • The local environment and any contributing catchments Studies in the UK have shown satisfactory operation of porous pavement systems without maintenance for over 10 years and recent work by Imbe et al. at gth ICUD, Portland, 2002 describes systems operating for over 20 years without maintenance. However, performance under such regimes could not be guaranteed, Table i shows typical recommended maintenance regimes: 4 of 10 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Pervious Pavements SD-20 Table 1 Typical Recommended Maintenance Regimes Activity Schedule Minimize use of salt or grit for de-icing Keep landscaped areas well maintained Prevent soil being washed onto pavement Ongoing Vacuum clean surface using commercially available sweeping machines at the following times: End of winter (April) Mid-summer (July / August) After Autumn leaf-fall (November) 2/3 x per year Inspect outlets Annual If routine cleaning does not restore infiltration rates, then reconstruction of part of the whole of a pervious surface maybe required. The surface area affected by hydraulic failure should be lifted for inspection of the internal materials to identify the location and extent of the blockage. Surface materials should be lifted and replaced after brush cleaning. Geotextiles may need complete replacement. Sub-surface layers may need cleaning and replacing. Removed silts may need to be disposed of as controlled waste. As needed (infrequent) Maximum 15-20 years Permeable pavements are up to 25 % cheaper (or at least no more expensive than the traditional forms of pavement construction), when all construction and drainage costs are taken into account. (Accepting that the porous asphalt itself is a more expensive surfacing, the extra cost of which is offset by the savings in underground pipework etc.) (Niemczynowicz, et al., 1987) Table l gives US cost estimates for capital and maintenance costs of porous pavements (Landphair et al., 2000) Redeveloping Existing Installations Various jurisdictional stormwater management and mitigation plans (SUSMP, WQMP, etc.) define "redevelopment" in terms of amounts of additional impervious area, increases in gross floor area and/or exterior construction, and land disturbing activities with structural or impervious surfaces. The definition of " redevelopment" must be consulted to determine whether or not the requirements for new development apply to areas intended for redevelopment. If the definition applies, the steps outlined under "designing new installations" above should be followed. January 2003 California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbooks.com 5 of 10 SD-20 Pervious Pavements Additional Information Cost Considerations Permeable pavements are up to 25 % cheaper (or at least no more expensive than the traditional forms of pavement construction), when all construction and drainage costs are taken into account. (Accepting that the porous asphalt itself is a more expensive surfacing, the extra cost of which is offset by the savings in underground pipework etc.) (Niemczynowicz, et al., 1987) Table 2 gives US cost estimates for capital and maintenance costs of porous pavements (Landphair et al., 2000) 6 of 10 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Pervious Pavements ( SD-20 Table 2 Engineer's Estimate for Porous Pavement Porous Pavement Item Grading Pa^Aio Excavation Flttar Faisrfc Stone Fill Sand Sight Wai Seeding Check Dam Unite SY SY CY SY CY CY £A LF CY Price $2.00 $19.00 $3.60 $1.15 $16.00 $7.00 $300-00 $0.05 $36.00 Total Construction Costs Constriction Costs Amortised For 20 Years CvcUs/Year Qwmt.1 AcreWS 604 212 201 TOO 201 100 2 844 0 Total $1,203 $4,02S $724 $805 $3,216 $700 $600 $32 $0 110,10$ $505 Quant* Z AcreWS 1209 424 403 1400 403 200 3 1288 0 ToW $2,418 $8,056 $1,451 $1,610 $6,448 $1,400 $900 $64 $0 $19,929 $999 Own*. 5 AcreWS 1812 036 $04 2000 604 300 4 1932 0 Total $3,624 $12,Q$4 $2P1T4 $2,300 $9,e&4 $2,100 $1,200 $97 $0 $29,614 f«v«i QuuL4 AcreWS 2419 fi4S aoe 2800 aoe 400 7 2576 0 Tol»l $4,036 $16,112 $2,902 $3,220 $12,696 $2,800 $2,100 $129 $0 $40,1i8 $2,008 Qeaw.5 AcrtWS 3020 ioeoiooa $600 1008 500 7 3220 0 T«Ud $6,040 $20,140 $3,629 $4,140 $16,128 $3,500 $2,100 $161 $0 $49,798 $2,490 Annual Maintenance Expense Hem Sweeping Washing Inspection Deep Clean Dulls AC AC MH AC Price $250.00 $250-00 $20.00 $460-00 Cycle*/ Vtare 6 a 0-5 Oral. 1 AcreWS 1 1 § 1 Total Annual Maintenance Expanse TWal $1,500 $1,500 $100 $225 $3,960 Quint 2 AcreWS 2 2 5 2 Tolll $3.000 $3,000 $100 $450 $7,792 QnaM.3 AcreWS 3 3 5 3 Tatal $4f500 $4^00 $100 $675 $113S1 QuanM AcreWS 4 4 5 39 Twtal £6,000 $6,000 $100 $»7e $«M*3 Qnwt.5 AcreWS 5 5 5 $ Toul $7,600 $7,SOO $100 $1,126 $19,370 January 2003 California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbooks.com 7 of 10 SD-20 Pervious Pavements Supplemental Information Other Resources Abbott C.L. and Comino-Mateos L. 2001. In situ performance monitoring of an infiltration drainage system and field testing of current design procedures. Journal CIWEM, 15(3), pp.igS- 202. Construction Industry Research and Information Association (CIRIA). 2002. Source Control using Constructed Pervious Surfaces €582, London, SWiP 3AU. Construction Industry Research and Information Association (CIRIA). 2000. Sustainable urban drainage systems - design manual for Scotland and Northern Ireland Report €521, London, SWiP 3AU. Construction Industry Research and Information Association (CIRIA). 2000 C522 Sustainable urban drainage systems - design manual for England and Wales, London, SWiP 3AU. Construction Industry Research and Information Association (CIRIA). RP448 Manual of good practice for the design, construction and maintenance of infiltration drainage systems for stormwater runoff control and disposal, London, SWiP 3AU. Dierkes C., Kuhlmann L., Kandasamy J. & Angelis G. Pollution Retention Capability and Maintenance of Permeable Pavements. Proc 9th International Conference on Urban Drainage, Portland Oregon, September 2002. Hart P (2002) Permeable Paving as a Stormwater Source Control System. Paper presented at Scottish Hydraulics Study Group 14th Annual seminar, SUDS. 22 March 2002, Glasgow. Kobayashi M., 1999. Stormwater runoff control in Nagoya City. Proc. 8 th Int. Conf. on Urban Storm Drainage, Sydney, Australia, pp.825-833. Landphair, H., McFalls, J., Thompson, D., 2000, Design Methods, Selection, and Cost Effectiveness of Stormwater Quality Structures, Texas Transportation Institute Research Report 1837-1, College Station, Texas. Legret M, Colandini V, Effects of a porous pavement with reservior strucutre on runoff water: water quality and the fate of heavy metals. Laboratoire Central Des Ponts et Chaussesss Macdonald K. & Jefferies C. Performance Comparison of Porous Paved and Traditional Car Parks. Proc. First National Conference on Sustainable Drainage Systems, Coventry June 2001. Niemczynowicz J, Hogland W, 1987: Test of porous pavements performed in Lund, Sweden, in Topics in Drainage Hydraulics and Hydrology. BC. Yen (Ed.), pub. Int. Assoc. For Hydraulic Research, pp 19-80. Pratt C.J. SUSTAINABLE URBAN DRAINAGE - A Review of published material on the performance of various SUDS devices prepared for the UK Environment Agency. Coventry University, UK December 2001. 8 of 10 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Pervious Pavements SD-20 Pratt C.J., 1995. Infiltration drainage - case studies of UK practice. Project Report 22,Construction Industry Research and Information Association, London, SWiP 3AU; also known as National Rivers Authority R & D Note 485 Pratt. C. J., 1990. Permeable Pavements for Stormwater Quality Enhancement. In: Urban Stormwater Quality Enhancement - Source Control, retrofitting and combined sewer technology, Ed. H.C. Torno, ASCE, ISBN 087262 7594, pp. 131-155 Raimbault G., 1997 French Developments in Reservoir Structures Sustainable water resources I the 21st century. Malmo Sweden Schliiter W. & Jefferies C. Monitoring the outflow from a Porous Car Park Proc. First National Conference on Sustainable Drainage Systems, Coventry June 2001. Wild, T.C., Jefferies, C., and D'Arcy, B.J. SUDS in Scotland - the Scottish SUDS database Report No SR(O2)O9 Scotland and Northern Ireland Forum for Environmental Research, Edinburgh. In preparation August 2002. January 2003 California Stormwater BMP Handbook 9 of 1 New Development and Redevelopment www.cabmphandbooks.com SD-20 Pervious Pavements Gcolexble L w- „ _«. _^J Perrneabte * j - . ' aj Sub-base | v * * * „! , >.To(urih«r , _ _ ^ ^ ._ -, i Permeable Impermeable ..... '"'*' afsposaf Seotextite T * » T * * Sub-baseMembrane or reuse Infiltration (a) Pervious pavement used for attenuation (b) Pervious pavement used (or infiltration Schematics of a Pervious Pavement System 10 Of 10 California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbooks.com January 2003 Trash Storage Areas SD-32 . . Design ObjectivesDescription Trash storage areas are areas where a trash receptacle (s) are Maximize Infiltration located for use as a repository for solid wastes. Stormwater Provide Retention runoff from areas where trash is stored or disposed of can be c. Dl ,„„«,,.,-. ,,... , ,. i j j ^ • ^ -i Slow Runoffpolluted. In addition, loose trash and debns can be easily transported by water or wind into nearby storm drain inlets, Minimize lmPervious Land channels, and/or creeks. Waste handling operations that may be overage sources of stormwater pollution include dumpsters, litter control, Prohibit Dumping of Improper and waste piles. Materials J Contain Pollutants Approach Collect and Convey This fact sheet contains details on the specific measures required to prevent or reduce pollutants in stormwater runoff associated with trash storage and handling. Preventative measures including enclosures, containment structures, and impervious pavements to mitigate spills, should be used to reduce the likelihood of contamination. Suitable Applications Appropriate applications include residential, commercial and industrial areas planned for development or redevelopment. (Detached residential single-family homes are typically excluded from this requirement.) Design Considerations Design requirements for waste handling areas are governed by Building and Fire Codes, and by current local agency ordinances and zoning requirements. The design criteria described in this fact sheet are meant to enhance and be consistent with these code and ordinance requirements. Hazardous waste should be handled in accordance with legal requirements established in Title 22, California Code of Regulation. Wastes from commercial and industrial sites are typically hauled by either public or commercial carriers that may have design or access requirements for waste storage areas. The design criteria in this fact sheet are recommendations and are not intended to be in conflict with requirements established by the waste hauler. The waste hauler should be contacted prior to the design of your site trash collection areas. Conflicts or issues should be discussed with the local agency. Designing New Installations Trash storage areas should be designed to consider the following structural or treatment control BMPs: • Design trash container areas so that drainage from adjoining roofs and pavement is diverted around the area(s) to avoid run-on. This might include berming or grading the waste handling area to prevent run-on of stormwater.. Make sure trash container areas are screened or walled to stormwater prevent off-site transport of trash. Quality Association January 2003 California Stormwater BMP Handbook 1 of 2 New Development and Redevelopment www.cabmphandbooks.com SD-32 Trash Storage Areas • Use lined bins or dumpsters to reduce leaking of liquid waste. • Provide roofs, awnings, or attached lids on all trash containers to minimize direct precipitation and prevent rainfall from entering containers. • Pave trash storage areas with an impervious surface to mitigate spills. • Do not locate storm drains in immediate vicinity of the trash storage area. • Post signs on all dumpsters informing users that hazardous materials are not to be disposed of therein. Redeveloping Existing Installations Various jurisdictional stormwater management and mitigation plans (SUSMP, WQMP, etc.) define "redevelopment" in terms of amounts of additional impervious area, increases in gross floor area and/or exterior construction, and land disturbing activities with structural or impervious surfaces. The definition of " redevelopment" must be consulted to determine whether or not the requirements for new development apply to areas intended for redevelopment. If the definition applies, the steps outlined under "designing new installations" above should be followed. Additional Information Maintenance Considerations The integrity of structural elements that are subject to damage (i.e., screens, covers, and signs) must be maintained by the owner/operator. Maintenance agreements between the local agency and the owner/operator may be required. Some agencies will require maintenance deed restrictions to be recorded of the property title. If required by the local agency, maintenance agreements or deed restrictions must be executed by the owner/operator before improvement plans are approved. Other Resources A Manual for the Standard Urban Stormwater Mitigation Plan (SUSMP), Los Angeles County Department of Public Works, May 2002. Model Standard Urban Storm Water Mitigation Plan (SUSMP) for San Diego County, Port of San Diego, and Cities in San Diego County, February 14, 2002. Model Water Quality Management Plan (WQMP) for County of Orange, Orange County Flood Control District, and the Incorporated Cities of Orange County, Draft February 2003. Ventura Countywide Technical Guidance Manual for Stormwater Quality Control Measures, July 2002. 2 of 2 California Stormwater BMP Handbook . January 2003 New Development and Redevelopment www.cabmphandbooks.com APPENDIX H Vortex Separator MP-51 Description Vortex separators: (alternatively, swirl concentrators) are gravity separators, and in principle are essentially wet vaults. The difference from wet vaults, however, is that the vortex separator is round, rather than rectangular, and the water moves in a centrifugal fashion before exiting. By having the water move in a circular fashion, rather than a straight line as is the case with a standard wet vault, it is possible to obtain significant removal of suspended sediments and attached pollutants with less space. Vortex separators were originally developed for combined sewer overflows (CSOs), where it is used primarily to remove coarse inorganic solids. Vortex separation has been adapted to Stormwater treatment by several manufacturers. California Experience There are currently about 100 installations in California. Advantages • May provide the desired performance in less space and therefore less cost. • May be more cost-effective pre-treatment devices than traditional wet or dry basins. • Mosquito control may be less of an issue than with traditional wet basins. Limitations • As some of the systems have standing water that remains between storms, there is concern about mosquito breeding. • It is likely that vortex separators are not as effective as wet vaults at removing fine sediments, on the order 50 to 100 microns in diameter and less. • The area served is limited by the capacity of the largest models. • As the products come in standard sizes, the facilities will be oversized in many cases relative to the design treatment storm, increasing the cost. • The non-steady flows of Stormwater decreases the efficiency of vortex separators from what may be estimated or _ determined from testing under constant flow. » Do not remove dissolved pollutants. • A loss of dissolved pollutants may occur as accumulated organic Design Considerations • Service Area • Settling Velocity • Appropriate Sizing • Inlet Pipe Diameter Targeted Constituents / Sediment A / Nutrients « S Trash / Metals « Bacteria •S Oil and Grease / Organics Legend (Removal Effectiveness) • Low • High A Medium A California Stormwater Quality Association January 2003 California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbooks.com lof 5 MP-51 Vortex Separator matter (e.g., leaves) decomposes in the units. Design and Sizing Guidelines The stormwater enters, typically below the effluent line, tangentially into the basin, thereby imparting a circular motion in the system. Due to centrifugal forces created by the circular motion, the suspended particles move to the center of the device where they settle to the bottom. There are two general types of vortex separation: free vortex and dampened (or impeded) vortex. Free vortex separation becomes dampened vortex separation by the placement of radial baffles on the weir-plate that impede the free vortex-flow pattern It has been stated with respect to CSOs that the practical lower limit of vortex separation is a particle with a settling velocity of 12 to 16.5 feet per hour (o.io to 0.14 cm/s). As such, the focus for vortex separation in CSOs has been with settleable solids generally 200 microns and larger, given the presence of the lighter organic solids. For inorganic sediment, the above settling velocity range represents a particle diameter of 50 to 100 microns. Head loss is a function of the size of the target particle. At 200 microns it is normally minor but increases significantly if the goal is to remove smaller particles. The commercial separators applied to stormwater treatment vary considerably with respect to geometry, and the inclusion of radial baffles and internal circular chambers. At one extreme is the inclusion of a chamber within the round concentrator. Water flows initially around the perimeter between the inner and outer chambers, and then into the inner chamber, giving rise to a sudden change in velocity that purportedly enhances removal efficiency. The opposite extreme is to introduce the water tangentially into a round manhole with no internal parts of any kind except for an outlet hood. Whether the inclusion of chambers and baffles gives better performance is unknown. Some contend that free vortex, also identified as swirl concentration, creates less turbulence thereby increasing removal efficiency. One product is unique in that it includes a static separator screen. • Sized is based on the peak flow of the design treatment event as specified by local government. • If an in-line facility, the design peak flow is four times the peak of the design treatment event. • If an off-line facility, the design peak flow is equal to the peak of the design treatment event. • Headloss differs with the product and the model but is generally on the order of one foot or less in most cases. Construction/Inspection Considerations No special considerations. Performance Manufacturer's differ with respect to performance claims, but a general statement is that the manufacturer's design and rated capacity (cfs) for each model is based on and believed to achieve an aggregate reduction of 90% of all particles with a specific gravity of 2.65 (glacial sand) down to 150 microns, and to capture the floatables, and oil and grease. Laboratory tests of two products support this claim. The stated performance expectation therefore implies that a 2 of 5 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Vortex Separator MP-51 lesser removal efficiency is obtained with particles less than 150 microns, and the lighter, organic settleables. Laboratory tests of one of the products found about 60% removal of 50 micron sand at the expected average operating flow rate Experience with the use of vortex separators for treating combined sewer overflows (CSOs), the original application of this technology, suggests that the lower practical limit for particle removal are particles with a settling velocity of 12 feet per hour (Sullivan, 1982), which represents a particle diameter of 100 to 200 microns, depending on the specific gravity of the particle. The CSO experience therefore seems consistent with the limited experience with treating stormwater, summarized above Traditional treatment technologies such as wet ponds and extended detention basins are generally believed to be more effective at removing very small particles, down to the range of 10 to 20 microns. Hence, it is intuitively expected that vortex separators do not perform as well as the traditional wet and dry basins, and filters. Whether this matters depends on the particle size distribution of the sediments in stormwater. If the distribution leans towards small material, there should be a marked difference between vortex separators and, say, traditional wet vaults. There are little data to support this conjecture In comparison to other treatment technologies, such as wet ponds and grass swales, there are few studies of vortex separators. Only two of manufactured products currently available have been field tested. Two field studies have been conducted. Both achieved in excess of 80% removal of TSS. However, the test was conducted in the Northeast (New York state and Maine) where it is possible the stormwater contained significant quantities of deicing sand. Consequently, the influent TSS concentrations and particle size are both likely considerably higher than is found in California stormwater. These data suggest that if the stormwater particles are for the most part fine (i.e., less than 50 microns), vortex separators will not be as efficient as traditional treatment BMPs such as wet ponds and swales, if the latter are sized according to the recommendations of this handbook. There are no equations that provide a straightforward determination of efficiency as a function of unit configuration and size. Design specifications of commercial separators are derived from empirical equations that are unique and proprietary to each manufacturer. However, some general relationships between performance and the geometry of a separator have been developed. CSO studies have found that the primary determinants of performance of vortex separators are the diameters of the inlet pipe and chamber with all other geometry proportional to these two. Sullivan et al. (1982) found that performance is related to the ratios of chamber to inlet diameters, D2/Di, and height between the inlet and outlet and the inlet diameter, Hi/Di, shown in Figure 3. The relationships are: as Da/Di approaches one, the efficiency decreases; and, as the Hi/Di ratio decreases, the efficiency decreases. These relationships may allow qualitative comparisons of the alternative designs of manufacturers. Engineers who wish to apply these concepts should review relevant publications presented in the References. Siting Criteria There are no particularly unique siting criteria. The size of the drainage area that can be served by vortex separators is directly related to the capacities of the largest models. January 2003 California Stormwater BMP Handbook 3 of 5 New Development and Redevelopment www.cabmphandbooks.com MP-51 Vortex Separator Additional Design Guidelines Vortex separators have two capacities if positioned as in-line facilities, a treatment capacity and a hydraulic capacity. Failure to recognize the difference between the two may lead to significant under sizing; i.e., too small a model is selected. This observation is relevant to three of the five products. These three technologies all are designed to experience a unit flow rate of about 24 gallons/square foot of separator footprint at the peak of the design treatment event. This is the horizontal area of the separator zone within the container, not the total footprint of the unit. At this unit flow rate, laboratory tests by these manufacturers have established that the performance will meet the general claims previously described. However, the units are sized to handle 100 gallons/square foot at the peak of the hydraulic event. Hence, in selecting a particular model the design engineer must be certain to match the peak flow of the design event to the stated treatment capacity, not the hydraulic capacity. The former is one-fourth the latter. If the unit is positioned as an off-line facility, the model selected is based on the capacity equal to the peak of the design treatment event. Maintenance Maintenance consists of the removal of accumulated material with an eductor truck. It may be necessary to remove and dispose the floatables separately due to the presence of petroleum product. Maintenance Requirements Remove all accumulated sediment, and litter and other floatables, annually, unless experience indicates the need for more or less frequent maintenance. Cost Manufacturers provide costs for the units including delivery. Installation costs are generally on the order of 50 to 100 % of the manufacturer's cost. For most sites the units are cleaned annually. Cost Considerations The different geometry of the several manufactured separators suggests that when comparing the costs of these systems to each other, that local conditions (e.g., groundwater levels) may affect the relative cost-effectiveness. References and Sources of Additional Information Field, R., 1972, The swirl concentrator as a combined sewer overflow regulator facility, EPA/R2- 72-008, U.S. Environmental Protection Agency, Washington, D.C. Field, R., D. Averill, T.P. O'Connor, and P. Steel, 1997, Vortex separation technology, Water Qual. Res. J. Canada, 32, i, 185 Manufacturers technical materials Sullivan, R.H., et al., 1982, Design manual - swirl and helical bend pollution control devices, EPA-6oo/8-82/oi3, U.S. Environmental Protection Agency, Washington, D.C. Sullivan, R.H., M.M. Cohn, J.E. Ure, F.F. Parkinson, and G. Caliana, 1974, Relationship between diameter and height for the design of a swirl concentrator as a combined sewer overflow regulator, EPA 670/2-74-039, U.S. Environmental Protection Agency, Washington, D.C. 4 of 5 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Vortex Separator MP-51 Sullivan, R.H., M.M. Cohn, J.E. Ure, F.F. Parkinson, and G. Caliana, 1974, The swirl concentrator as a grit separator device, EPA67O/2-74-O26, U.S. Environmental Protection Agency, Washington, D.C. Sullivan, R.H., M.M. Cohn, J.E. Ure, F.F. Parkinson, and G. Caliana, 1978, Swirl primary separator device and pilot demonstration, EPA6OO/2-78-126, U.S. Environmental Protection Agency, Washington, D.C. January 2003 California Stormwater BMP Handbook 5 of 5 New Development and Redevelopment www.cabmphandbooks.com Infiltration Basin TC-11 Description An infiltration basin is a shallow impoundment that is designed to infiltrate Stormwater. Infiltration basins use the natural filtering ability of the soil to remove pollutants in Stormwater runoff. Infiltration facilities store runoff until it gradually exfiltrates through the soil and eventually into the water table. This practice has high pollutant removal efficiency and can also help recharge groundwater, thus helping to maintain low flows in stream systems. Infiltration basins can be challenging to apply on many sites, however, because of soils requirements. In addition, some studies have shown relatively high failure rates compared with other management practices. California Experience Infiltration basins have a long history of use in California, especially in the Central Valley. Basins located in Fresno were among those initially evaluated in the National Urban Runoff Program and were found to be effective at reducing the volume of runoff, while posing little long-term threat to groundwater quality (EPA, 1983; Schroeder, 1995). Proper siting of these devices is crucial as underscored by the experience of Caltrans in siting two basins in Southern California. The basin with marginal separation from groundwater and soil permeability failed immediately and could never be rehabilitated. Advantages • Provides 100% reduction in the load discharged to surface waters. • The principal benefit of infiltration basins is the approximation of pre-development hydrology during which a Design Considerations • Soil for Infiltration • Slope • Aesthetics Targeted Constituents •/ Sediment / Nutrients / Trash S Metals / Bacteria / Oil and Grease J Organics Legend (Removal Effectiveness) • Low • High A Medium California Stormwater Quality Association January 2003 California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbooks.com 1 of 8 TO 11 Infiltration Basin significant portion of the average annual rainfall runoff is infiltrated and evaporated rather than flushed directly to creeks. • If the water quality volume is adequately sized, infiltration basins can be useful for providing control of channel forming (erosion) and high frequency (generally less than the 2-year) flood events. Limitations • May not be appropriate for industrial sites or locations where spills may occur. • Infiltration basins require a minimum soil infiltration rate of 0.5 inches/hour, not appropriate at sites with Hydrologic Soil Types C and D. • If infiltration rates exceed 2.4 inches/hour, then the runoff should be fully treated prior to infiltration to protect groundwater quality. • Not suitable on fill sites or steep slopes. • Risk of groundwater contamination in very coarse soils. • Upstream drainage area must be completely stabilized before construction. • Difficult to restore functioning of infiltration basins once clogged. Design and Sizing Guidelines • Water quality volume determined by local requirements or sized so that 85% of the annual runoff volume is captured. • Basin sized so that the entire water quality volume is infiltrated within 48 hours. • Vegetation establishment on the basin floor may help reduce the clogging rate. Construction/Inspection Considerations m Before construction begins, stabilize the entire area draining to the facility. If impossible, place a diversion berm around the perimeter of the infiltration site to prevent sediment entrance during construction or remove the top 2 inches of soil after the site is stabililized. Stabilize the entire contributing drainage area, including the side slopes, before allowing any runoff to enter once construction is complete. • Place excavated material such that it can not be washed back into the basin if a storm occurs during construction of the facility. • Build the basin without driving heavy equipment over the infiltration surface. Any equipment driven on the surface should have extra-wide ("low pressure") tires. Prior to any construction, rope off the infiltration area to stop entrance by unwanted equipment. • After final grading, till the infiltration surface deeply. • Use appropriate erosion control seed mix for the specific project and location. 2 of 8 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Infiltration Basin TC-11 Performance As water migrates through porous soil and rock, pollutant attenuation mechanisms include precipitation, sorption, physical filtration, and bacterial degradation. If functioning properly, this approach is presumed to have high removal efficiencies for particulate pollutants and moderate removal of soluble pollutants. Actual pollutant removal in the subsurface would be expected to vary depending upon site-specific soil types. This technology eliminates discharge to surface waters except for the very largest storms; consequently, complete removal of all stormwater constituents can be assumed. There remain some concerns about the potential for groundwater contamination despite the findings of the NURP and Nightingale (1975; I987a,b,c; 1989). For instance, a report by Pitt et al. (1994) highlighted the potential for groundwater contamination from intentional and unintentional stormwater infiltration. That report recommends that infiltration facilities not be sited in areas where high concentrations are present or where there is a potential for spills of toxic material. Conversely, Schroeder (1995) reported that there was no evidence of groundwater impacts from an infiltration basin serving a large industrial catchment in Fresno, CA. Siting Criteria The key element in siting infiltration basins is identifying sites with appropriate soil and hydrogeologic properties, which is critical for long term performance. In one study conducted in Prince George's County, Maryland (Galli, 1992), all of the infiltration basins investigated clogged within 2 years. It is believed that these failures were for the most part due to allowing infiltration at sites with rates of less than 0.5 in/hr, basing siting on soil type rather than field infiltration tests, and poor construction practices that resulted in soil compaction of the basin invert. A study of 23 infiltration basins in the Pacific Northwest showed better long-term performance in an area with highly permeable soils (Hilding, 1996). In this study, few of the infiltration basins had failed after 10 years. Consequently, the following guidelines for identifying appropriate soil and subsurface conditions should be rigorously adhered to. • Determine soil type (consider RCS soil type 'A, B or C' only) from mapping and consult USDA soil survey tables to review other parameters such as the amount of silt and clay, presence of a restrictive layer or seasonal high water table, and estimated permeability. The soil should not have more than 30% clay or more than 40% of clay and silt combined. Eliminate sites that are clearly unsuitable for infiltration. • Groundwater separation should be at least 3 m from the basin invert to the measured ground water elevation. There is concern at the state and regional levels of the impact on groundwater quality from infiltrated runoff, especially when the separation between groundwater and the surface is small. • Location away from buildings, slopes and highway pavement (greater than 6 m) and wells and bridge structures (greater than 30 m). Sites constructed of fill, having a base flow or with a slope greater than 15% should not be considered. • Ensure that adequate head is available to operate flow splitter structures (to allow the basin to be offline) without ponding in the splitter structure or creating backwater upstream of the splitter. January 2003 California Stormwater BMP Handbook 3 of 8 New Development and Redevelopment www.cabmphandbooks.com TO 11 Infiltration Basin • Base flow should not be present in the tributary watershed. Secondary Screening Based on Site Geotechnical Investigation • At least three in-hole conductivity tests shall be performed using USER 7300-89 or Bouwer- Rice procedures (the latter if groundwater is encountered within the boring), two tests at different locations within the proposed basin and the third down gradient by no more than approximately 10 m. The tests shall measure permeability in the side slopes and the bed within a depth of 3 m of the invert. • The minimum acceptable hydraulic conductivity as measured in any of the three required test holes is 13 mm/hr. If any test hole shows less than the minimum value, the site should be disqualified from further consideration. • Exclude from consideration sites constructed in fill or partially in fill unless no silts or clays are present in the soil boring. Fill tends to be compacted, with clays in a dispersed rather than flocculated state, greatly reducing permeability. • The geotechnical investigation should be such that a good understanding is gained as to how the stormwater runoff will move in the soil (horizontally or vertically) and if there are any geological conditions that could inhibit the movement of water. Additional Design Guidelines (1) Basin Sizing - The required water quality volume is determined by local regulations or sufficient to capture 85% of the annual runoff. (2) Provide pretreatment if sediment loading is a maintenance concern for the basin. (3) Include energy dissipation in the inlet design for the basins. Avoid designs that include a permanent pool to reduce opportunity for standing water and associated vector problems. (4) Basin invert area should be determined by the equation: A_WQVA —b where A = Basin invert area (m2) WQV = water quality volume (m3) k = 0.5 times the lowest field-measured hydraulic conductivity (m/hr) t = drawdown time (48 hr) (5) The use of vertical piping, either for distribution or infiltration enhancement shall not be allowed to avoid device classification as a Class V injection well per 40 CFRi46.5(e)(4). 4 of 8 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Infiltration Basin TC-11 Maintenance Regular maintenance is critical to the successful operation of infiltration basins. Recommended operation and maintenance guidelines include: • Inspections and maintenance to ensure. • Observe drain time for the design storm after completion or modification of the facility to confirm that the desired drain time has been obtained. • Schedule semiannual inspections for beginning and end of the wet season to identify potential problems such as erosion of the basin side slopes and invert, standing water, trash and debris, and sediment accumulation. • Remove accumulated trash and debris in the basin at the start and end of the wet season. • Inspect for standing water at the end of the wet season. • Trim vegetation at the beginning and end of the wet season to prevent establishment of woody vegetation and for aesthetic and vector reasons. • Remove accumulated sediment and regrade when the accumulated sediment volume exceeds 10% of the basin. • If erosion is occurring within the basin, revegetate immediately and stabilize with an erosion control mulch or mat until vegetation cover is established. • To avoid reversing soil development, scarification or other disturbance should only be performed when there are actual signs of clogging, rather than on a routine basis. Always remove deposited sediments before scarification, and use a hand-guided rotary tiller, if possible, or a disc harrow pulled by a very light tractor. Cost Infiltration basins are relatively cost-effective practices because little infrastructure is needed when constructing them. One study estimated the total construction cost at about $2 per ft (adjusted for inflation) of storage for a o.ss-acre basin (SWRPC, 1991). As with other BMPs, these published cost estimates may deviate greatly from what might be incurred at a specific site. For instance, Caltrans spent about $i8/fts for the two infiltration basins constructed in southern California, each of which had a water quality volume of about 0.34 ac.-ft. Much of the higher cost can be attributed to changes in the storm drain system necessary to route the runoff to the basin locations. Infiltration basins typically consume about 2 to 3% of the site draining to them, which is relatively small. Additional space may be required for buffer, landscaping, access road, and fencing. Maintenance costs are estimated at 5 to 10% of construction costs. One cost concern associated with infiltration practices is the maintenance burden and longevity. If improperly maintained, infiltration basins have a high failure rate. Thus, it may be necessary to replace the basin with a different technology after a relatively short period of time. January 2003 California Stormwater BMP Handbook 5 of 8 New Development and Redevelopment www.cabmphandbooks.com TO 11 Infiltration Basin References and Sources of Additional Information Caltrans, 2002, BMP Retrofit Pilot Program Proposed Final Report, Rpt. CTSW-RT-oi-oso, California Dept. of Transportation, Sacramento, CA. Galli, J. 1992. Analysis of Urban BMP Performance and Longevity in Prince George's County, Maryland. Metropolitan Washington Council of Governments, Washington, DC. Hilding, K. 1996. Longevity of infiltration basins assessed in Puget Sound. Watershed Protection Techniques i(3):i24~i25. Maryland Department of the Environment (MDE). 2000. Maryland Stormwater Design Manual, http://www.mde.state.md.us/environment/wnia/stormwatermanual. Accessed May 22, 2OO2. Nightingale, H.I., 1975, "Lead, Zinc, and Copper in Soils of Urban Storm-Runoff Retention Basins," American Water Works Assoc. Journal. Vol. 67, p. 443-446. Nightingale, H.I., 19873, "Water Quality beneath Urban Runoff Water Management Basins," Water Resources Bulletin, Vol. 23, p. 197-205. Nightingale, H.I., I987b, "Accumulation of As, Ni, Cu, and Pb in Retention and Recharge Basin Soils from Urban Runoff," Water Resources Bulletin, Vol. 23, p. 663-672. Nightingale, H.I., 1987C, "Organic Pollutants in Soils of Retention/Recharge Basins Receiving Urban Runoff Water," Soil Science Vol. 148, pp. 39-45. Nightingale, H.I., Harrison, D., and Salo, J.E., 1985, "An Evaluation Technique for Ground- water Quality Beneath Urban Runoff Retention and Percolation Basins," Ground Water Monitoring Review, Vol. 5, No. i, pp. 43-50. Oberts, G. 1994. Performance of Stormwater Ponds and Wetlands in Winter. Watershed Protection Techniques 1(2): 64-68. Pitt, R., et al. 1994, Potential Groundwater Contamination from Intentional and Nonintentional Stormwater Infiltration, EPA/6oo/R-94/osi, Risk Reduction Engineering Laboratory, U.S. EPA, Cincinnati, OH. Schueler, T. 1987. Controlling Urban Runoff: A Practical Manual for Planning and Designing Urban BMPs. Metropolitan Washington Council of Governments, Washington, DC. Schroeder, R.A., 1995, Potential For Chemical Transport Beneath a Storm-Runoff Recharge (Retention) Basin for an Industrial Catchment in Fresno, CA, USGS Water-Resource Investigations Report 93-4140. Southeastern Wisconsin Regional Planning Commission (SWRPC). 1991. Costs of Urban Nonpoint Source Water Pollution Control Measures. Southeastern Wisconsin Regional Planning Commission, Waukesha, WI. U.S. EPA, 1983, Results of the Nationwide Urban Runoff Program: Volume i - Final Report, WH-554, Water Planning Division, Washington, DC. 6 of 8 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Infiltration Basin TC-11 Watershed Management Institute (WMI). 1997. Operation, Maintenance, and Management of Stormwater Management Systems. Prepared for U.S. Environmental Protection Agency Office of Water, Washington, DC. Information Resources Center for Watershed Protection (CWP). 1997. Stormwater BMP Design Supplement for Cold Climates. Prepared for U.S. Environmental Protection Agency Office of Wetlands, Oceans and Watersheds. Washington, DC. Ferguson, B.K., 1994. Stormwater Infiltration. CRC Press, Ann Arbor, MI. USEPA. 1993. Guidance to Specify Management Measures for Sources ofNonpoint Pollution in Coastal Waters. EPA-84O-B-92-OO2. U.S. Environmental Protection Agency, Office of Water, Washington, DC. January 2003 California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbooks.com 7 of 8 TO 11 Infiltration Basin STILLING BASIN EMERGENCY SPILLWAY »»*»»»»»» FLAT BASIN FLOOR WITH "-GRASS TURF *,* *,:,:.; BACKUP UNDERDRAIN * RISER/ BARREL PLAN VIEW EMBANKMENT - RISER- EMERGENCY SPILLWAY INFILTRATION STi BACKUP UNDERDRAIN PIPE IN CASE OF STANDING WATER PROBLEMS ANTI-SEEP COLLAR or - FILTER DIAPHRAGM PROFILE 8 of 8 California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbooks.com January 2003 Multiple System Fact Sheet TC-60 Design Considerations • Area Required • Slope • Water Availability • Hydraulic Head • Environmental Side-effects Targeted Constituents Description A multiple treatment system uses two or more BMPs in series. Some examples of multiple systems include: settling basin combined with a sand filter; settling basin or biofilter combined with an infiltration basin or trench; extended detention zone on a wet pond. California Experience The research wetlands at Fremont, California are a combination of wet ponds, wetlands, and vegetated controls. Advantages • BMPs that are less sensitive to high pollutant loadings, especially solids, can be used to pretreat runoff for sand filters and infiltration devices where the potential for clogging exists. • BMPs which target different constituents can be combined to provide treatment for all constituents of concern. • BMPs which use different removal processes (sedimentation, filtration, biological uptake) can be combined to improve the overall removal efficiency for a given constituent. • BMPs in series can provide redundancy and reduce the likelihood of total system failure. Limitations • Capital costs of multiple systems are higher than for single devices. • Space requirements are greater than that required for a single technology. Design and Sizing Guidelines Refer to individual treatment control BMP fact sheets. Performance • Be aware that placing multiple BMPs in series does not necessarily result in combined cumulative increased performance. This is because the first BMP may already achieve part of the gain normally achieved by the second BMP. On the other hand, picking the right combination can often help optimize performance of the second BMP since the influent to the second BMP is of more consistent water quality, and thus more consistent performance, thereby allowing the BMP to achieve its highest performance. • When addressing multiple constituents through multiple BMPs, one BMP may optimize removal of a particular constituent, while another BMP optimizes removal of a different S Sediment / Nutrients y Trash J Metals / Bacteria y Oil and Grease / Organics Legend (Removal Effectiveness) • Low • High A Medium January 2003 California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbooks.com 1 of 2 TC-60 Multiple System Fact Sheet constituent or set of constituents. Therefore, selecting the right combination of BMPs can be very constructive in collectively removing multiple constituents. Siting Criteria Refer to individual treatment control BMP fact sheets. Additional Design Guidelines • When using two or more BMPs in series, it may be possible to reduce the size of BMPs. • Existing pretreatment requirements may be able to be avoided when using some BMP combinations. Maintenance Refer to individual treatment control BMP fact sheets. Cost Refer to individual treatment control BMP fact sheets. Resources and Sources of Additional Information Refer to individual treatment control BMP fact sheets. 2 of 2 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Section 6 Long-term Maintenance of BMPs 6.1 Introduction The long-term performance of BMPs hinges on ongoing and proper maintenance. In order for this to occur detailed maintenance plans are needed that include specific maintenance activities and frequencies for each type of BMP. In addition, these should include indicators for assessing when "as needed" maintenance activities are required. The fact sheets included in this volume contain the basic information needed to develop these maintenance plans, but municipalities and other regulatory agencies also need to identify the responsible party and potentially to address funding requirements. The following discussion is based primarily on data developed by Horner et al. (1994) and information available at http://www.stormwatercenter.net/ 6.2 Critical Regulatory Components Critical regulatory components identified by Horner et al. (1994) include: • Regulations should officially designate a responsible party, frequently the development site owner, to have ultimate responsibility for the continued maintenance of stormwater facilities. This official designation provides the opportunity for appropriate preparation and budgeting prior to actually assuming responsibilities. It also facilitates enforcement or other legal remedies necessary to address compliance or performance problems once the facility has been constructed. • Regulations should clearly state the inspection and maintenance requirements. Inspection and maintenance requirements should also comply with all applicable statutes and be based on the needs and priorities of the individual measure or facility. A clear presentation will help owners and builders comply and inspectors enforce requirements. • Regulations should contain comprehensive requirements for documenting and detailing maintenance. A facility operation and maintenance manual should be prepared containing accurate and comprehensive drawings or plans of the completed facility and detailed descriptions and schedules of inspection and maintenance. • The regulations should delineate the procedure for maintenance noncompliance. This process should provide informal, discretionary measures to deal with periodic, inadvertent noncompliance and formal and severe measures to address chronic noncompliance or performance problems. In either case, the primary goal of enforcement is to maintain an effective BMP - the enforcement action should not become an end in itself. • Regulations should also address the possibility of total default by the owner or builder by providing a way to complete construction and continue maintenance. For example, the public might assume maintenance responsibility. If so, the designated public agency must be alerted and possess the necessary staffing, equipment, expertise, and funding to assume this responsibility. Default can be addressed through bonds and other performance January 2003 California Stormwater BMP Handbook 6-1 New Development and Redevelopment www.cabmphandbooks.com Section 6 Long-term Maintenance ofBMPs guarantees obtained before the project is approved and construction begins. These bonds can then be used to fund the necessary maintenance activities. • The regulations must recognize that adequate and secure funding is needed for facility inspection and maintenance and provide for such funding. 6.3 Enforcement Options A public agency will sometimes need to compel those responsible for facility construction or maintenance to fulfill their obligations. Therefore, the maintenance program must have enforcement options for quick corrective action. Rather than a single enforcement measure, the program should have a variety of techniques, each with its own degree of formality and legal weight. The inspection program should provide for nonconforming performance and even default, and contain suitable means to address all stages. Prior to receiving construction approval, the developer or builder can be forced to provide performance guarantees. The public agency overseeing the construction can use these guarantees, usually a performance bond or other surety in an amount equal to some fraction of the facility's construction cost, to fund maintenance activities. Enforcement of maintenance requirements can be accomplished through a stormwater maintenance agreement, which is a formal contract between a local government and a property owner designed to guarantee that specific maintenance functions are performed in exchange for permission to develop that property (http://www.stormwatercenter.net/). Local governments benefit from these agreements in that responsibility for regular maintenance of the BMPs can be placed upon the property owner or other legally recognized party, allowing agency staff more time for plan review and inspection. 6.4 Maintenance Agreements Maintenance agreements can be an effective tool for ensuring long-term maintenance of on-site BMPs. The most important aspect of creating these maintenance agreements is to clearly define the responsibilities of each party entering into the agreement. Basic language that should be incorporated into an agreement includes the following: 1. Performance of Routine Maintenance Local governments often find it easier to have a property owner perform all maintenance according to the requirements of a Design Manual. Other communities require that property owners do aesthetic maintenance (i.e., mowing, vegetation removal) and implement pollution prevention plans, but elect to perform structural maintenance and sediment removal themselves. 2. Maintenance Schedules Maintenance requirements may vary, but usually governments require that all BMP owners perform at least an annual inspection and document the maintenance and repairs performed. An annual report must then be submitted to the government, who may then choose to perform an inspection of the facility. 6-2 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Section 6 Long-term Maintenance ofBMPs 3. Inspection Requirements Local governments may obligate themselves to perform an annual inspection of a BMP, or may choose to inspect when deemed necessary instead. Local governments may also wish to include language allowing maintenance requirements to be increased if deemed necessary to ensure proper functioning of the BMP. 4. Access to BMPs The agreement should grant permission to a local government or its authorized agent to enter onto property to inspect BMPs. If deficiencies are noted, the government should then provide a copy of the inspection report to the property owner and provide a timeline for repair of these deficiencies. 5. Failure to Maintain In the maintenance agreement, the government should repeat the steps available for addressing a failure to maintain situation. Language allowing access to BMPs cited as not properly maintained is essential, along with the right to charge any costs for repairs back to the property owner. The government may wish to include deadlines for repayment of maintenance costs, and provide for liens against property up to the cost of the maintenance plus interest. 6. Recording Of The Maintenance Agreement An important aspect to the recording of the maintenance agreement is that the agreement be recorded into local deed records. This helps ensure that the maintenance agreement is bound to the property in perpetuity. Finally, some communities elect to include easement requirements into their maintenance agreements. While easement agreements are often secured through a separate legal agreement, recording public access easements for maintenance in a maintenance agreement reinforces a local government's right to enter and inspect a BMP. Examples of maintenance agreements include several available on the web at: http://www.stormwatercenter.net/ 6.5 Public Funding Sources If local agencies are willing to assume responsibility for stormwater BMPs, it is essential to identify the long-term funding sources. Several of these are described below: General Tax Revenues Tax revenues are an obvious source of funding, particularly for the long-term inspection and maintenance of existing runoff and drainage facilities. The benefits and protection to the public from continued safe and effective operation of the facility justifies using revenues from general funds. To use tax revenues, particularly from a general fund, the inspection and maintenance program must annually compete with all other programs included in the government's annual operating budget. This inconsistent and unreliable funding makes securing a long-term financial January 2003 California Stormwater BMP Handbook 6-3 New Development and Redevelopment www.cabmphandbooks.com Section 6 Long-term Maintenance ofBMPs commitment to inspection and maintenance difficult and subject to political pressures. Nevertheless, tax revenues remain a popular funding source because the collection and disbursement system is already in place and familiar. Utility Charges Using utility charges to fund inspection and maintenance is a somewhat recent application of an already established financing technique. In addition, several municipalities and counties throughout the country have runoff management, drainage, and flood control authorities or districts to provide residents with runoff related services. Using utility charge financing has several advantages. By addressing only runoff needs and benefits, utility funding avoids competing with other programs and needs. Utility funding also demonstrates a direct link between the funding and the services it provides. This approach can require an entirely new operating system and organization that needs legal authorization to exist, operate, and assess charges. The effort required to create such an entity can deter many, although the continued success of established authorities and growth of new ones have done much to allay concerns over the effort required. In a runoff utility, the user charges are often based on the need for services rather than the benefits derived from them. While charges are based on actual costs to inspect and maintain runoff facilities and measures within the service area, the assessed rate structure should relate to site characteristics. These include property area size, extent of impervious coverage, and other factors with a direct and demonstrable effect on runoff. To be fair, the rate structure should also remain simple and understandable to the ratepayer. To finance the stormwater utility in Prince William County, Virginia, residential and nonresidential owners of developed property pay based on the amount of impervious area (rooftops, paved areas, etc.) on their property. Residents pay $10.38 billed twice a year ($20.76 total annual fee) for detached singe-family homes. Town home and condominium owners will pay $7.785 billed twice a year ($15.57 total annual fee). Nonresidential property owners pay $0.84 per 1,000 ft2 of impervious area per month. Fee adjustments or credits may be available if a stormwater management system is already in place. The fee will be on the real estate bills. Fees for the stormwater utility in Austin, Texas are higher with residential users billed $5.79/mo, while commercial users pay $94.62/mo/acre of impervious cover. These fees cover not only maintenance of existing BMPs, but also capital improvement projects related to the drainage infrastructure. Permit Fees Collecting permit fees to finance runoff inspection and maintenance is a long standing funding procedure. Most governmental entities local, county, and state can establish and collect fees and other charges to obtain operating funds for programs and services. Many inspection services, most notably the construction inspection of both ESC measures and permanent drainage and runoff management facilities, are financed at least in part through fees collected by permitting agencies. Unlike taxes or some utility charges, inspection costs are borne by those who need them. 6-4 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Section 6 Long-term Maintenance ofBMPs The permit fee collection program should have a demonstrable link to the runoff management or drainage systems. The public agency should demonstrate a direct link between the permit fees collected and the permitted project one method is using dedicated accounts for individual projects and facilities. Finally, the rate structure should reflect site characteristics such as area size or imperviousness that directly relate to the measure or facility by affecting runoff or erosion. Dedicated Contributions Public agencies at times have used developer contributions to fund long-term facility maintenance. This approach is particularly appropriate in single-family residential subdivisions, where numerous individual property owners served by a single runoff facility can result in confusion over who has maintenance responsibility. The exact funding technique depends on many factors, including community attitude and knowledge, economic and political viability, and program needs and costs. Some techniques, including permit fees and dedicated contributions, may be more appropriate for short-term activities, such as construction inspection. Others utility charges and specialized tax revenues may apply to all phases of an inspection and maintenance program but require considerable effort and special legal authorization to operate. January 2003 California Stormwater BMP Handbook 6-5 New Development and Redevelopment www.cabmphandbooks.com APPENDIX I ARCHITECTURAL SERIES .DOWN SPOUT FILTER ASSEMBLY Removes non-soluble pollutants normally found on building roofs. Available for both standard and custom applications* Another innovative stormwater management product from KriStar, H ARCHITECTURAL SERIES DOWNSPOUT FILTER ASSEMBLY FEATURES • Handles non-soluble solids such as sediment, Sravel; hydrocarbons • Uses the same effective filter medium as the the other FloGard filter products Custom size or shape downspout pipe connections available Easy, economical installation Easy, low cost maintenance Tamper proof, waterproof, hinged access door Standard round downspout outlet connection* Standard round downspout inlet connection* Removable, slide-in collection basket The FloGard™ Downspout Filter Assembly is typically installed on commercial or industrial building downspout (downdrain) pipes for the removal of non-soluble pollutants normally found on building roofs (sediment, gravel, hydrocarbons, etc.). Constructed of corrosion-resistant stainless steel (Type 304), the FloGard™ Downspout Filter is designed to accept either 4" or 6" diameter downspout pipes. Special size or shape downspout pipe connections are available upon request. FloGard™ Downspout Filters offer a tamper-proof, water-proof, hinged access door and easy slide-in pollutant collection basket for ease of maintenance. Specifications Model No. FG-DS6 Inlet Diameter 6" (Sch. 40) Outlet Diameter 6" (Sch. 40) Outside Dimensions 18" x 24" x 7" FG-DS4 Inlet Diameter 4" (Sch. 40) Outlet Diameter 4" (Sch. 40) Outside Dimensions 18" x 24" x 5" Clean Flow Rate Bypass Flow Area (%) 455 gpm( 1.01 cfs) 125%min. ' Non-standard shapes and dimensions available upon request ©2003 KriStar Enterprises, Inc. FloGard™ is a registered trademarb of KriStar Enterprises, Inc. KriStar Enterprises, Inc. • P.O. Box 7352 • Santa Rosa, CA 95407-0352 Go with "The Flo". Fossil Flo" PH: 800-579-8819 • FAX: 707-524-8186 • www.kristar.com Flo-Gard Downspout Filter Flow Sizing Chart Model No. FG-DS4 FG-DS6 Inlet/Outlet ID (Sch 40 size) 4 6 Unit OD (in x in x in) 18x24x5 18x24x7 Filtered Flow (cfs) 0.3 0.4 Total Bypass Area (%)* 129 97 * As % of inlet cross-sectional area Revised 04/18/03 P*LO£ 1/4 APPENDIX J Section 3 Erosion and Sediment Control BMPs 3.1 Erosion Control Erosion control is any source control practice that protects the soil surface and prevents soil particles from being detached by rainfall, flowing water, or wind. Erosion control is also referred to as soil stabilization. Erosion control consists of preparing the soil surface and implementing one or more of the BMPs shown in Table 3-1, to disturbed soil areas. All inactive soil disturbed areas on the project site, and most active areas prior to the on set of rain, must be protected from erosion. Soil disturbed areas may include relatively flat areas as well as slopes. Typically, steep slopes and large exposed areas require the most robust erosion controls; flatter slopes and smaller areas still require protection, but less costly materials may be appropriate for these areas, allowing savings to be directed to the more robust BMPs for steep slopes and large exposed areas. To be effective, erosion control BMPs for slopes at disturbed areas must be protected from concentrated flows. Some erosion control BMPs can be used effectively to temporarily prevent erosion by concentrated flows. These BMPs, used alone or in combination, prevent erosion by intercepting: diverting, conveying and discharging concentrated flows in a manner that prevents soil detachment and transport. Temporary concentrated flow conveyance controls may be required to direct runon around or through the project in a non-erodible fashion. Temporary concentrated flow conveyance controls include the following BMPs: • EC-9, Earth Dikes and Drainage Swales • EC-io, Velocity Dissipation Devices • EC-n, Slope Drains Table 3-1 Erosion Control BMPs BMP* EC-l EC-2 EC-3 EC-4 EC-5 EC-6 EC-7 EC-8 EC-9 EC-io EC-ii EC-12 EC-13 BMP Name Scheduling Preservation of Existing Vegetation Hydraulic Mulch Hydroseeding Soil Binders Straw Mulch Geotextiles & Mats Wood Mulching Earth Dikes and Drainage Swales Velocity Dissipation Devices Slope Drains Streambank Stabilization Polyacrylamide January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 3-1 Table 3-2 Temporary Sediment Control BMPs BMP* SE-i SE-2 SE-3 SE-4 SE-5 SE-6 SE-7 SE-8 SE-g SE-io BMP Name Silt Fence Sediment Basin Sediment Trap Check Dam Fiber Rolls Gravel Bag Berm Street Sweeping and Vacuuming Sandbag Barrier Straw Bale Barrier Storm Drain Inlet Protection Section 3 Erosion and Sediment Control BMPs 3.2 Sediment Control Sediment control is any practice that traps soil particles after they have been detached and moved by rain, flowing water, or wind. Sediment control measures are usually passive systems that rely on filtering or settling the particles out of the water or wind that is transporting them. Sediment control practices include the BMPs listed in Table 3-2. Sediment control BMPs include those practices that intercept and slow or detain the flow of stormwater to allow sediment to settle and be trapped. Sediment control practices can consist of installing linear sediment barriers (such as silt fence, sandbag barrier, and straw bale barrier); providing fiber rolls, gravel bag berms, or check dams to break up slope length or flow; or constructing a sediment trap or sediment basin. Linear sediment barriers are typically placed below the toe of exposed and erodible slopes, down-slope of exposed soil areas, around soil stockpiles, and at other appropriate locations along the site perimeter. A few BMPs may control both sediment and erosion, for example, fiber rolls and sand bag barriers. The authors of this handbook have classified these BMPs as either erosion control (EC) or sediment control (SC) based on the authors opinion on the BMPs most common and effective use. Sediment control BMPs are most effective when used in conjunction with erosion control BMPs. The combination of erosion control and sediment control is usually the most effective means to prevent sediment from leaving the project site and potentially entering storm drains or receiving waters. Under most conditions the General Permit requires that the discharger implement an effective combination of erosion and sediment controls. Under limited circumstances, sediment control, alone may be appropriate. For example, applying erosion control BMPs to an area where excavation, filling, compaction, or grading is currently under way may not be feasible when storms come unexpectedly. Use of sediment controls by establishing perimeter control on these areas may be appropriate and allowable under the General Permit provided the following conditions are met. • Weather monitoring is under way. • Inactive soil disturbed areas have been protected with an effective combination of erosion and sediment controls. 3-2 California Stormwater BMP Handbook Construction www.cabmphandbooks.com January 2003 Section 3 Erosion and Sediment Control BMPs • An adequate supply of sediment control materials are on site and there are sufficient forces of labor and equipment available to implement sediment controls on the active area prior to the on set of rain. • The SWPPP adequately describes the methods to protect active areas. 3.3 Wind Erosion Control Wind erosion control consists of applying water or other dust palliatives to prevent or alleviate dust nuisance. Wind erosion control best management practices (BMPs) are shown in Table 3-3. Table 3-3 Wind Erosion Control BMPs BMP* WE-i BMP Name Wind Erosion Control Other BMPs that are sometimes applied to disturbed soil areas in order to control wind erosion are BMPs EC-2 through EC-y, shown in Section 3.1 of this Manual. Be advised that many of the dust palliatives may contain compounds that have an unknown effect on stormwater. A sampling and analysis protocol to test for stormwater contamination from exposure to such compounds is required in the SWPPP. 3.4 Tracking Control BMPs Tracking control consists of preventing or reducing the tracking of sediment off-site by vehicles leaving the construction area. Tracking control best management practices (BMPs) are shown in Table 3-4. Table 3-4 Temporary Tracking Control BMPs BMP* TC-i TC-2 TC-3 BMP Name Stabilized Construction Entrance/ Exit Stabilized Construction Roadway Entrance/Outlet Tire Wash Attention to control of tracking sediment off site is highly recommended, as dirty streets and roads near a construction site create a nuisance to the public and generate constituent complaints to elected officials and regulators. These complaints often result in immediate inspections and regulatory actions. 3.5 Erosion and Sediment Control BMP Fact Sheet Format A BMP fact sheet is a short document that gives all the information about a particular BMP. Typically each fact sheet contains the information outlined in Figure 3-1. Completed fact sheets for each of the above activities are provided in Section 3.6. The fact sheets also contain side bar presentations with information on BMP objectives, targeted constituents, removal effectiveness, and potential alternatives. 3.6 BMP Fact Sheets BMP fact sheets for erosion, sediment, wind, and tracking EC-xx Example Fact Sheet Description and Purpose Suitable Applications Limitations Implementation Costs Inspection and Maintenance References Figure 3-1 Example Fact Sheet January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 3-3 Section 3 Erosion and Sediment Control BMPs controls follow. The BMP fact sheets are individually page numbered and are suitable for photocopying and inclusion in SWPPPs. Fresh copies of the fact sheets can be individually downloaded from the California Stormwater BMP Handbook web site at www.cabmphandbooks.corn. 3-4 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Scheduling EC-1 Description and Purpose Scheduling is the development of a written plan that includes sequencing of construction activities and the implementation of BMPs such as erosion control and sediment control while taking local climate (rainfall, wind, etc.) into consideration. The purpose is to reduce the amount and duration of soil exposed to erosion by wind, rain, runoff, and vehicle tracking, and to perform the construction activities and control practices in accordance with the planned schedule. Suitable Applications Proper sequencing of construction activities to reduce erosion potential should be incorporated into the schedule of every construction project especially during rainy season. Use of other, more costly yet less effective, erosion and sediment control BMPs may often be reduced through proper construction sequencing. Limitations • Environmental constraints such as nesting season prohibitions reduce the full capabilities of this BMP. Implementation • Avoid rainy periods. Schedule major grading operations during dry months when practical. Allow enough time before rainfall begins to stabilize the soil with vegetation or physical means or to install sediment trapping devices. • Plan the project and develop a schedule showing each phase of construction. Clearly show how the rainy season relates to soil Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: v Primary Objective / Secondary Objective Targeted Constituents Sediment Nutrients Trash Metals Bacteria Oil and Grease Organics PotentiaS Alternatives None ASQA Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 3 EC-1 Scheduling disturbing and re-stabilization activities. Incorporate the construction schedule into the SWPPP. • Include on the schedule, details on the rainy season implementation and deployment of: Erosion control BMPs Sediment control BMPs Tracking control BMPs Wind erosion control BMPs Non-stormwater BMPs Waste management and materials pollution control BMPs • Include dates for activities that may require non-stormwater discharges such as dewatering, sawcutting, grinding, drilling, boring, crushing, blasting, painting, hydro-demolition, mortar mixing, pavement cleaning, etc. • Work out the sequencing and timetable for the start and completion of each item such as site clearing and grubbing, grading, excavation, paving, foundation pouring utilities installation, etc., to minimize the active construction area during the rainy season. Sequence trenching activities so that most open portions are closed before new trenching begins. Incorporate staged seeding and re-vegetation of graded slopes as work progresses. Schedule establishment of permanent vegetation during appropriate planting time for specified vegetation. • Non-active areas should be stabilized as soon as practical after the cessation of soil disturbing activities or one day prior to the onset of precipitation. • Monitor the weather forecast for rainfall. • When rainfall is predicted, adjust the construction schedule to allow the implementation of soil stabilization and sediment treatment controls on all disturbed areas prior to the onset of rain. • Be prepared year round to deploy erosion control and sediment control BMPs. Erosion may be caused during dry seasons by un-seasonal rainfall, wind, and vehicle tracking. Keep the site stabilized year round, and retain and maintain rainy season sediment trapping devices in operational condition. • Apply permanent erosion control to areas deemed substantially complete during the project's defined seeding window. Costs Construction scheduling to reduce erosion may increase other construction costs due to reduced economies of scale in performing site grading. The cost effectiveness of scheduling techniques should be compared with the other less effective erosion and sedimentation controls to achieve a cost effective balance. 2 of 3 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Scheduling EC-1 Inspection and Maintenance • Verify that work is progressing in accordance with the schedule. If progress deviates, take corrective actions. • Amend the schedule when changes are warranted. • Amend the schedule prior to the rainy season to show updated information on the deployment and implementation of construction site BMPs. References Stormwater Quality Handbooks Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Stormwater Management for Construction Activities Developing Pollution Prevention Plans and Best Management Practices (EPA 832-^92-005), U.S. Environmental Protection Agency, Office of Water, September 1992. January 2003 California Stormwater BMP Handbook 3 of 3 Construction www.cabmphandbooks.com Preservation Of Existing Vegetation EC-2 Description and Purpose Carefully planned preservation of existing vegetation minimizes the potential of removing or injuring existing trees, vines, shrubs, and grasses that protect soil from erosion. Suitable Applications Preservation of existing vegetation is suitable for use on most projects. Large project sites often provide the greatest opportunity for use of this BMP. Suitable applications include the following: • Areas within the site where no construction activity occurs, or occurs at a later date. This BMP is especially suitable to multi year projects where grading can be phased. • Areas where natural vegetation exists and is designated for preservation. Such areas often include steep slopes, watercourse, and building sites in wooded areas. • Areas where local, state, and federal government require preservation, such as vernal pools, wetlands, marshes, certain oak trees, etc. These areas are usually designated on the plans, or in the specifications, permits, or environmental documents. • Where vegetation designated for ultimate removal can be temporarily preserved and be utilized for erosion control and sediment control. Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: S Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives None Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 4 EC-2 Preservation Of Existing Vegetation Limitations • Requires forward planning by the owner/developer, contractor, and design staff. • Limited opportunities for use when project plans do not incorporate existing vegetation into the site design. • For sites with diverse topography, it is often difficult and expensive to save existing trees while grading the site satisfactory for the planned development. Implementation The best way to prevent erosion is to not disturb the land. In order to reduce the impacts of new development and redevelopment, projects may be designed to avoid disturbing land in sensitive areas of the site (e.g., natural watercourses, steep slopes), and to incorporate unique or desirable existing vegetation into the site's landscaping plan. Clearly marking and leaving a buffer area around these unique areas during construction will help to preserve these areas as well as take advantage of natural erosion prevention and sediment trapping. Existing vegetation to be preserved on the site must be protected from mechanical and other injury while the land is being developed. The purpose of protecting existing vegetation is to ensure the survival of desirable vegetation for shade, beautification, and erosion control. Mature vegetation has extensive root systems that help to hold soil in place, thus reducing erosion. In addition, vegetation helps keep soil from drying rapidly and becoming susceptible to erosion. To effectively save existing vegetation, no disturbances of any kind should be allowed within a defined area around the vegetation. For trees, no construction activity should occur within the drip line of the tree. Timing m Provide for preservation of existing vegetation prior to the commencement of clearing and grubbing operations or other soil disturbing activities in areas where no construction activity is planned or will occur at a later date. Design and Layout m Mark areas to be preserved with temporary fencing. Include sufficient setback to protect roots. - Orange colored plastic mesh fencing works well. - Use appropriate fence posts and adequate post spacing and depth to completely support the fence in an upright position. • Locate temporary roadways, stockpiles, and layout areas to avoid stands of trees, shrubs, and grass. » Consider the impact of grade changes to existing vegetation and the root zone. • Maintain existing irrigation systems where feasible. Temporary irrigation may be required. • Instruct employees and subcontractors to honor protective devices. Prohibit heavy equipment, vehicular traffic, or storage of construction materials within the protected area. 2 of 4 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Preservation Of Existing Vegetation EC-2 Costs There is little cost associated with preserving existing vegetation if properly planned during the project design, and these costs may be offset by aesthetic benefits that enhance property values. During construction, the cost for preserving existing vegetation will likely be less than the cost of applying erosion and sediment controls to the disturbed area. Replacing vegetation inadvertently destroyed during construction can be extremely expensive, sometimes in excess of $10,000 per tree. Inspection and Maintenance During construction, the limits of disturbance should remain clearly marked at all times. Irrigation or maintenance of existing vegetation should be described in the landscaping plan. If damage to protected trees still occurs, maintenance guidelines described below should be followed: • Verify that protective measures remain in place. Restore damaged protection measures immediately. • Serious tree injuries shall be attended to by an arborist. • Damage to the crown, trunk, or root system of a retained tree shall be repaired immediately. • Trench as far from tree trunks as possible, usually outside of the tree drip line or canopy. Curve trenches around trees to avoid large roots or root concentrations. If roots are encountered, consider tunneling under them. When trenching or tunneling near or under trees to be retained, place tunnels at least 18 in. below the ground surface, and not below the tree center to minimize impact on the roots. • Do not leave tree roots exposed to air. Cover exposed roots with soil as soon as possible. If soil covering is not practical, protect exposed roots with wet burlap or peat moss until the tunnel or trench is ready for backfill. • Cleanly remove the ends of damaged roots with a smooth cut. • Fill trenches and tunnels as soon as possible. Careful filling and tamping will eliminate air spaces in the soil, which can damage roots. • If bark damage occurs, cut back all loosened bark into the undamaged area, with the cut tapered at the top and bottom and drainage provided at the base of the wood. Limit cutting the undamaged area as much as possible. • Aerate soil that has been compacted over a trees root zone by punching holes 12 in. deep with an iron bar, and moving the bar back and forth until the soil is loosened. Place holes 18 in. apart throughout the area of compacted soil under the tree crown. • Fertilization - Fertilize stressed or damaged broadleaf trees to aid recovery. - Fertilize trees in the late fall or early spring. January 2003 California Stormwater BMP Handbook 3 of 4 Construction www.cabmphandbooks.com EC-2 Preservation Of Existing Vegetation - Apply fertilizer to the soil over the feeder roots and in accordance with label instructions, but never closer than 3 ft to the trunk. Increase the fertilized area by one-fourth of the crown area for conifers that have extended root systems. • Retain protective measures until all other construction activity is complete to avoid damage during site cleanup and stabilization. References County of Sacramento Tree Preservation Ordinance, September 1981. Stormwater Quality Handbooks Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Stormwater Management of the Puget Sound Basin, Technical Manual, Publication #91-75, Washington State Department of Ecology, February 1992. Water Quality Management Plan for The Lake Tahoe Region, Volume II, Handbook of Management Practices, Tahoe Regional Planning Agency, November 1988. o 4 of 4 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Hydraulic Mulch EC-3 Description and Purpose Hydraulic mulch consists of applying a mixture of shredded wood fiber or a hydraulic matrix, and a stabilizing emulsion or tackifier with hydro-mulching equipment, which temporarily protects exposed soil from erosion by raindrop impact or wind. Suitable Applications Hydraulic mulch is suitable for soil disturbed areas requiring temporary protection until permanent stabilization is established, and disturbed areas that will be re-disturbed following an extended period of inactivity. Limitations Wood fiber hydraulic mulches are generally short lived and need 24 hours to dry before rainfall occurs to be effective. May require a second application in order to remain effective for an entire rainy season. Implementation • Prior to application, roughen embankment and fill areas by rolling with a crimping or punching type roller or by track walking. Track walking shall only be used where other methods are impractical. • To be effective, hydraulic matrices require 24 hours to dry before rainfall occurs. • Avoid mulch over spray onto roads, sidewalks, drainage channels, existing vegetation, etc. Objectives EC SE TC WE NS WM Erosion Control •/ Sediment Control Tracking Control Wind Erosion Control / Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: J Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives EC-4 Hydroseeding EC-5 Soil Binders EC-6 Straw Mulch EC-7 Geotextiles and Mats EC-8 Wood Mulching CASQA rnla Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 3 EC-3 Hydraulic Mulch • Paper based hydraulic mulches alone shall not be used for erosion control. { Hydraulic Mulches Wood fiber mulch can be applied alone or as a component of hydraulic matrices. Wood fiber applied alone is typically applied at the rate of 2,000 to 4,000 Ib/acre. Wood fiber mulch is manufactured from wood or wood waste from lumber mills or from urban sources. Hydraulic Matrices Hydraulic matrices include a mixture of wood fiber and acrylic polymer or other tackifier as binder. Apply as a liquid slurry using a hydraulic application machine (i.e., hydro seeder) at the following minimum rates, or as specified by the manufacturer to achieve complete coverage of the target area: 2,000 to 4,000 Ib/acre wood fiber mulch, and 5 to 10% (by weight) of tackifier (acrylic copolymer, guar, psyllium, etc.) Bonded Fiber Matrix Bonded fiber matrix (BFM) is a hydraulically applied system of fibers and adhesives that upon drying forms an erosion resistant blanket that promotes vegetation, and prevents soil erosion. BFMs are typically applied at rates from 3,000 Ib/acre to 4,000 Ib/acre based on the manufacturer's recommendation. A biodegradable BFM is composed of materials that are 100% biodegradable. The binder in the BFM should also be biodegradable and should not dissolve or disperse upon re-wetting. Typically, biodegradable BFMs should not be applied immediately before, during or immediately after rainfall if the soil is saturated. Depending on the product, BFMs typically require 12 to 24 hours to dry and become effective. Costs f Average cost for installation of wood fiber mulch is $9OO/acre. Average cost for installation of BFM is $5,500/acre. Inspection and Maintenance • Inspect BMPs prior to forecast rain, daily during extended rain events, after rain events, weekly during the rainy season, and at two-week intervals during the non-rainy season. • Areas where erosion is evident shall be repaired and BMPs re-applied as soon as possible. Care should be exercised to minimize the damage to protected areas while making repairs, as any area damaged will require re-application of BMPs. • Maintain an unbroken, temporary mulched ground cover throughout the period of construction when the soils are not being reworked. References Controlling Erosion of Construction Sites Agricultural Information #347, U.S. Department of Agriculture (USDA), Natural Resources Conservation Service (NRCS) (formerly Soil Conservation Service - SCS). Guides for Erosion and Sediment Control in California, USDA Soils Conservation Service, January 1991. Manual of Standards of Erosion and Sediment Control Measures, Association of Bay Area Governments, May 1995. 2 of 3 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Hydraulic Mulch EC-3 Sedimentation and Erosion Control, An Inventory of Current Practices Draft, US EPA, April 1990. Soil Erosion by Water, Agriculture Information Bulletin #513, U.S. Department of Agriculture, Soil Conservation Service. Stormwater Quality Handbooks Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Guidance Document: Soil Stabilization for Temporary Slopes, State of California Department of Transportation (Caltrans), November 1999 Stormwater Management of the Puget Sound Basin, Technical Manual, Publication #91-75, Washington State Department of Ecology, February 1992. Water Quality Management Plan for the Lake Tahoe Region, Volume II, Handbook of Management Practices, Tahoe Regional Planning Agency, November 1988. January 2003 California Stormwater BMP Handbook 3 of 3 Construction www.cabmphandbooks.com Hydroseeding EC-4 Description and Purpose Hydroseeding typically consists of applying a mixture of wood fiber, seed, fertilizer, and stabilizing emulsion with hydro- mulch equipment, to temporarily protect exposed soils from erosion by water and wind. Suitable Applications Hydroseeding is suitable for soil disturbed areas requiring temporary protection until permanent stabilization is established, and disturbed areas that will be re-disturbed following an extended period of inactivity. Limitations • Hydroseeding may be used alone only when there is sufficient time in the season to ensure adequate vegetation establishment and coverage to provide adequate erosion control. Otherwise, hydroseeding must be used in conjunction with mulching (i.e., straw mulch). • Steep slopes are difficult to protect with temporary seeding. • Temporary seeding may not be appropriate in dry periods without supplemental irrigation. • Temporary vegetation may have to be removed before permanent vegetation is applied. • Temporary vegetation is not appropriate for short term inactivity. Objectives EC SE TC WE NS Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control ...... Waste Management and Materials Pollution Control Legend: i/ Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives EC-3 Hydraulic Mulch EC-5 Soil Binders EC-6 Straw Mulch EC-7 Geotextiles and Mats EC-8 Wood Mulching QA nia Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 3 EC-4 Hydroseeding Implementation In order to select appropriate hydroseeding mixtures, an evaluation of site conditions shall be performed with respect to: Soil conditions - Maintenance requirements Site topography - Sensitive adjacent areas Season and climate - Water availability - Vegetation types - Plans for permanent vegetation The local office of the U.S.D.A. Natural Resources Conservation Service (NRCS) is an excellent source of information on appropriate seed mixes. The following steps shall be followed for implementation: • Avoid use of hydroseeding in areas where the BMP would be incompatible with future earthwork activities and would have to be removed. • Hydroseeding can be accomplished using a multiple step or one step process. The multiple step process ensures maximum direct contact of the seeds to soil. When the one step process is used to apply the mixture of fiber, seed, etc., the seed rate shall be increased to compensate for all seeds not having direct contact with the soil. .• Prior to application, roughen the area to be seeded with the furrows trending along the contours. • Apply a straw mulch to keep seeds in place and to moderate soil moisture and temperature until the seeds germinate and grow. • All seeds shall be in conformance with the California State Seed Law of the Department of Agriculture. Each seed bag shall be delivered to the site sealed and clearly marked as to species, purity, percent germination, dealer's guarantee, and dates of test. The container shall be labeled to clearly reflect the amount of Pure Live Seed (PLS) contained. All legume seed shall be pellet inoculated. Inoculant sources shall be species specific and shall be applied at a rate of 2 Ib of inoculant per 100 Ib seed. • Commercial fertilizer shall conform to the requirements of the California Food and Agricultural Code. Fertilizer shall be pelleted or granular form. • Follow up applications shall be made as needed to cover weak spots and to maintain adequate soil protection. • Avoid over spray onto roads, sidewalks, drainage channels, existing vegetation, etc. Costs Average cost for installation and maintenance may vary from as low as $300 per acre for flat slopes and stable soils, to $1600 per acre for moderate to steep slopes and/or erosive soils. 2 of 3 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Hydroseeding EC-4 Hydroseeding High Density Fast Growing Non-Competing Sterile Ornamentals Turf Species Bunch Grasses Annual Perennial Native Non-Native Cereal Grain Installed Cost per Acre $400 - $1600 $350 $300 - $1300 $350 - $650 $300 - $800 $300 - $1600 $400 - $500 $500 Source: Caltrans Guidance for Soil Stabilization for Temporary Slopes, Nov. 1999 Inspection and Maintenance • Inspect BMPs prior to forecast rain, daily during extended rain events, after rain events, weekly during the rainy season, and at two-week intervals during the non-rainy season. • Areas where erosion is evident shall be repaired and BMPs re-applied as soon as possible. Care should be exercised to minimize the damage to protected areas while making repairs, as any area damaged will require re-application of BMPs. • Where seeds fail to germinate, or they germinate and die, the area must be re-seeded, fertilized, and mulched within the planting season, using not less than half the original application rates. • Irrigation systems, if applicable, should be inspected daily while in use to identify system malfunctions and line breaks. When line breaks are detected, the system must be shut down immediately and breaks repaired before the system is put back into operation. • Irrigation systems shall be inspected for complete coverage and adjusted as needed to maintain complete coverage. References Stormwater Quality Handbooks Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Guidance Document: Soil Stabilization for Temporary Slopes, State of California Department of Transportation (Caltrans), November 1999. January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 3 of 3 Soil Binders EC-5 Objectives Description and Purpose Soil binders consist of applying and maintaining a soil stabilizer to exposed soil surfaces. Soil binders are materials applied to the soil surface to temporarily prevent water induced erosion of exposed soils on construction sites. Soil binders also prevent wind erosion. Suitable Applications Soil binders are typically applied to disturbed areas requiring short term temporary protection. Because soil binders can often be incorporated into the work, they are a good alternative to mulches in areas where grading activities will soon resume. Soil binders are also suitable for use on stockpiles. Limitations • Soil binders are temporary in nature and may need reapplication. • Soil binders require a minimum curing time until fully effective, as prescribed by the manufacturer. Curing time may be 24 hours or longer. Soil binders may need reapplication after a storm event. • Soil binders will generally experience spot failures during heavy rainfall events. If runoff penetrates the soil at the top of a slope treated with a soil binder, it is likely that the runoff will undercut the stabilized soil layer and discharge at a point further down slope. EC SE TC WE NS WM Erosion Control •/ Sediment Control Tracking Control Wind Erosion Control s Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: */ Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives EC-3 Hydraulic Mulch EC-4 Hydroseeding EC-6 Straw Mulch EC-7 Geotextiles and Mats EC-8 Wood Mulching CASQA Ifornla Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 7 EC-5 Soil Binders • Soil binders do not hold up to pedestrian or vehicular traffic across treated areas. • Soil binders may not penetrate soil surfaces made up primarily of silt and clay, particularly when compacted. • Some soil binders may not perform well with low relative humidity. Under rainy conditions, some agents may become slippery or leach out of the soil. • Soil binders may not cure if low temperatures occur within 24 hours of application. • "The water quality impacts of soil binders are relatively unknown and some may have water quality impacts due to their chemical makeup. • A sampling and analysis plan must be incorporated into the SWPPP as soil binders could be a source of non-visible pollutants. Implementation General Considerations • Regional soil types will dictate appropriate soil binders to be used. • A soil binder must be environmentally benign (non-toxic to plant and animal life), easy to apply, easy to maintain, economical, and should not stain paved or painted surfaces. Soil binders should not pollute stormwater. • Some soil binders may not be compatible with existing vegetation. • Performance of soil binders depends on temperature, humidity, and traffic across treated areas. B Avoid over spray onto roads, sidewalks, drainage channels, existing vegetation, etc. Selecting a Soil Binder Properties of common soil binders used for erosion control are provided on Table i at the end of this BMP. Use Table i to select an appropriate soil binder. Refer to WE-i, Wind Erosion Control, for dust control soil binders. Factors to consider when selecting a soil binder include the following: • Suitability to situation - Consider where the soil binder will be applied, if it needs a high resistance to leaching or abrasion, and whether it needs to be compatible with any existing vegetation. Determine the length of time soil stabilization will be needed, and if the soil binder will be placed in an area where it will degrade rapidly. In general, slope steepness is not a discriminating factor for the listed soil binders. • Soil types and surface materials - Fines and moisture content are key properties of surface materials. Consider a soil binder's ability to penetrate, likelihood of leaching, and ability to form a surface crust on the surface materials. • Frequency of application - The frequency of application can be affected by subgrade conditions, surface type, climate, and maintenance schedule. Frequent applications could 2 of 7 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Soil Binders EOS lead to high costs. Application frequency may be minimized if the soil binder has good penetration, low evaporation, and good longevity. Consider also that frequent application will require frequent equipment clean up. Plant-Material Based (Short Lived) Binders Guar: Guar is a non-toxic, biodegradable, natural galactomannan based hydrocolloid treated with dispersant agents for easy field mixing. It should be mixed with water at the rate of 11 to 15 Ib per 1,000 gallons. Recommended minimum application rates are as follows: Application Rates for Guar Soil Stabilizer Slope (H:V): Ib/acre: Flat 40 4:1 45 3:1 50 2:1 60 i:l 70 Psyllium: Psyllium is composed of the finely ground muciloid coating of plantago seeds that is applied as a dry powder or in a wet slurry to the surface of the soil. It dries to form a firm but rewettable membrane that binds soil particles together but permits germination and growth of seed. Psyllium requires 12 to 18 hours drying time. Application rates should be from 80 to 200 Ib/acre, with enough water in solution to allow for a uniform slurry flow. Starch: Starch is non-ionic, cold water soluble (pre-gelatinized) granular cornstarch. The material is mixed with water and applied at the rate of 150 Ib/acre. Approximate drying time is 9 to 12 hours. Plant-Material Based (Long Lived) Binders Pitch and Rosin Emulsion: Generally, a non-ionic pitch and rosin emulsion has a minimum solids content of 48%. The rosin should be a minimum of 26% of the total solids content. The soil stabilizer should be non-corrosive, water dilutable emulsion that upon application cures to a water insoluble binding and cementing agent. For soil erosion control applications, the emulsion is diluted and should be applied as follows: • For clayey soil: 5 parts water to l part emulsion • For sandy soil: 10 parts water to l part emulsion Application can be by water truck or hydraulic seeder with the emulsion and product mixture applied at the rate specified by the manufacturer. Polymeric Emulsion Blend Binders Acrylic Copolymers and Polymers: Polymeric soil stabilizers should consist of a liquid or solid polymer or copolymer with an acrylic base that contains a minimum of 55% solids. The polymeric compound should be handled and mixed in a manner that will not cause foaming or should contain an anti-foaming agent. The polymeric emulsion should not exceed its shelf life or expiration date; manufacturers should provide the expiration date. Polymeric soil stabilizer should be readily miscible in water, non-injurious to seed or animal life, non-flammable, should provide surface soil stabilization for various soil types without totally inhibiting water infiltration, and should not re-emulsify when cured. The applied compound should air cure within a maximum of 36 to 48 hours. Liquid copolymer should be diluted at a rate of 10 parts water to i part polymer and the mixture applied to soil at a rate of 1,175 gallons/acre. January 2003 California Stormwater BMP Handbook 3 of 7 Construction www.cabmphandbooks.com EC-5 Soil Binders Liquid Polymers of Methacrylates and Acrylates: This material consists of a tackifier/sealer that is a liquid polymer of methacrylates and acrylates. It is an aqueous 100% acrylic emulsion blend of 40% solids by volume that is free from styrene, acetate, vinyl, ethoxylated surfactants or silicates. For soil stabilization applications, it is diluted with water in accordance with manufacturer's recommendations, and applied with a hydraulic seeder at the rate of 20 gallons/acre. Drying time is 12 to 18 hours after application. Copolymers of Sodium Acrylates and Acrylamides: These materials are non-toxic, dry powders that are copolymers of sodium acrylate and acrylamide. They are mixed with water and applied to the soil surface for erosion control at rates that are determined by slope gradient: Slope Gradient (H:V) Flat to 5:1 5:1 to 3:1 2:2 to 1:1 Ib/acre 3-0 - 5.0 5.0 - 10.0 1O.O - 2O.O Poly-Acrylamide and Copolymer of Acrylamide: Linear copolymer polyacrylamide is packaged as a dry flowable solid. When used as a stand alone stabilizer, it is diluted at a rate of nlb/i,ooo gal of water and applied at the rate of 5.0 Ib/acre. Hydro-Colloid Polymers: Hydro-Colloid Polymers are various combinations of dry flowable poly-acrylamides, copolymers and hydro-colloid polymers that are mixed with water and applied to the soil surface at rates of 55 to 60 Ib/acre. Drying times are o to 4 hours. Cementitious-Based Binders Gypsum: This is a formulated gypsum based product that readily mixes with water and mulch to form a thin protective crust on the soil surface. It is composed of high purity gypsum that is ground, calcined and processed into calcium sulfate hemihydrate with a minimum purity of 86%. It is mixed in a hydraulic seeder and applied at rates 4,000 to 12,000 Ib/acre. Drying time is 4 to 8 hours. Applying Soil Binders After selecting an appropriate soil binder, the untreated soil surface must be prepared before applying the soil binder. The untreated soil surface must contain sufficient moisture to assist the agent in achieving uniform distribution. In general, the following steps should be followed: • Follow manufacturer's written recommendations for application rates, pre-wetting of application area, and cleaning of equipment after use. • Prior to application, roughen embankment and fill areas. • Consider the drying time for the selected soil binder and apply with sufficient time before anticipated rainfall. Soil binders should not be applied during or immediately before rainfall. • Avoid over spray onto roads, sidewalks, drainage channels, sound walls, existing vegetation, etc. 4 Of 7 California Stormwater BMP Handbook Construction www.cabmphandbooks.com January 2003 Soil Binders EC-5 • Soil binders should not be applied to frozen soil, areas with standing water, under freezing or rainy conditions, or when the temperature is below 4O°F during the curing period. • More than one treatment is often necessary, although the second treatment may be diluted or have a lower application rate. • Generally, soil binders require a minimum curing time of 24 hours before they are fully effective. Refer to manufacturer's instructions for specific cure time. • For liquid agents: Crown or slope ground to avoid ponding. Uniformly pre-wet ground at 0.03 to 0.3 gal/yd2 or according to manufacturer's recommendations. - Apply solution under pressure. Overlap solution 6 to 12 in. Allow treated area to cure for the time recommended by the manufacturer; typically at least 24 hours. Apply second treatment before first treatment becomes ineffective, using 50% application rate. In low humidities, reactivate chemicals by re-wetting with water at o.i to 0.2 gal/yd2. Costs Costs vary according to the soil stabilizer selected for implementation. The following are approximate costs: Soil Binder Plant-Material Based (Short Lived) Binders Plant-Material Based (Long Lived) Binders Polymeric Emulsion Blend Binders Cementitious-Based Binders Cost per Acre $400 $1,200 $400 « $800 (i) $1,200 for Acrylic polymers and copolymers Source: Caltrans Guidance for Soil Stabilization for Temporary Slopes, Nov. 1999 Inspection and Maintenance • Inspect BMPs prior to forecast rain, daily during extended rain events, after rain events, weekly during the rainy season, and at two-week intervals during the non-rainy season. • Areas where erosion is evident shall be repaired and BMPs re-applied as soon as possible. Care should be exercised to minimize the damage to protected areas while making repairs, as any area damaged will require re-application of BMPs. • Reapply the selected soil binder as needed to maintain effectiveness. January 2003 California Stormwater BMP Handbook 5 of 7 Construction www.cabmphandbooks.com EC-5 Soil Binders References Manual of Standards of Erosion and Sediment Control Measures, Association of Bay Area Governments, May 1995. Sedimentation and Erosion Control, An Inventory of Current Practices Draft, US EPA, April 1990. Stormwater Quality Handbooks Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Guidance Document: Soil Stabilization for Temporary Slopes, State of California Department of Transportation (Caltrans), November 1999. Stormwater Management for Construction Activities, Developing Pollution Prevention Plans and Best Management Practices, EPA 832-11-92005; USEPA, April 1992. 3 6 of 7 California Stormwater BMP Handbook Construction www.cabmphandbooks.com January 2003 Soil Binders EC-5 Table 1 Properties of Soil Binders for Erosion Control Evaluation Criteria Relative Cost Resistance to Leaching Resistance to Abrasion Longevity Minimum Curing Time before Rain Compatibility with Existing Vegetation Mode of Degradation Labor Intensive Specialized Application Equipment Liquid/Powder Surface Crusting Clean Up Erosion Control Application Rate Binder Type Plant Material Based (Short Lived) Low High Moderate Short to Medium 9 to 18 hours Good Biodegradable No Water Truck or Hydraulic Mulcher Powder Yes, but dissolves on rewetting Water Varies M Plant Material Based (Long Lived) Low High Low Medium 19 to 24 hours Poor Biodegradable No Water Truck or Hydraulic Mulcher Liquid Yes Water Varies « Polymeric Emulsion Blends Low Low to Moderate Moderate to High Medium to Long o to 24 hours Poor Photodegradable/ Chemically Degradable No Water Truck or Hydraulic Mulcher Liquid/Powder Yes, but dissolves on rewetting Water Varies « Cementitious- Based Binders Low Moderate Moderate to High Medium 4 to 8 hours Poor Photodegradable/ Chemically Degradable No Water Truck or Hydraulic Mulcher Powder Yes Water 4,000 to 12,000 Ibs/acre (i) See Implementation for specific rates. January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 7 of 7 Straw Mulch EC-6 Objectives Description and Purpose Straw mulch consists of placing a uniform layer of straw and incorporating it into the soil with a studded roller or anchoring it with a tackifier stabilizing emulsion. Straw mulch protects the soil surface from the impact of rain drops, preventing soil particles from becoming dislodged. Suitable Applications Straw mulch is suitable for soil disturbed areas requiring temporary protection until permanent stabilization is established. Straw mulch is typically used for erosion control on disturbed areas until soils can be prepared for permanent vegetation. Straw mulch is also used in combination with temporary and/or permanent seeding strategies to enhance plant establishment. Limitations • Availability of straw and straw blowing equipment may be limited just prior to the rainy season and prior to storms due to high demand. • There is a potential for introduction of weed seed and unwanted plant material. • When straw blowers are used to apply straw mulch, the treatment areas must be within 150 ft of a road or surface capable of supporting trucks. • Straw mulch applied by hand is more time intensive and potentially costly. EC SE TC WE NS WM Erosion Control </ Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: V Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives EC-3 Hydraulic Mulch EC-4 Hydroseeding EC-5 Soil Binders EC-7 Geotextiles and Mats EC-8 Wood Mulching ASQA rnla Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 3 EC-6 Straw Mulch f • Wind may limit application of straw and blow straw into undesired locations. \ • May have to be removed prior to permanent seeding or prior to further earthwork. • "Punching" of straw does not work in sandy soils, necessitating the use of tackifiers. Implementation • Straw shall be derived from wheat, rice, or barley. Where required by the plans, specifications, permits, or environmental documents, native grass straw shall be used. • A tackifier is the preferred method for anchoring straw mulch to the soil on slopes. • Crimping, punch roller-type rollers, or track walking may also be used to incorporate straw mulch into the soil on slopes. Track walking shall only be used where other methods are impractical. • Avoid placing straw onto roads, sidewalks, drainage channels, sound walls, existing vegetation, etc. • Straw mulch with tackifier shall not be applied during or immediately before rainfall. • In San Diego, use of straw near wood framed home construction has been frowned on by the Fire Marshall. Application Procedures /-• ^ . • Apply straw at a minimum rate of 4,000 Ib/acre, either by machine or by hand distribution. v • Roughen embankments and fill rills before placing the straw mulch by rolling with a crimping or punching type roller or by track walking. • Evenly distribute straw mulch on the soil surface. • Anchor straw mulch to the soil surface by "punching" it into the soil mechanically (incorporating). Alternatively, use a tackifier to adhere straw fibers. • Methods for holding the straw mulch in place depend upon the slope steepness, accessibility, soil conditions, and longevity. On small areas, a spade or shovel can be used to punch in straw mulch. On slopes with soils that are stable enough and of sufficient gradient to safely support construction equipment without contributing to compaction and instability problems, straw can be "punched" into the ground using a knife blade roller or a straight bladed coulter, known commercially as a "crimper". On small areas and/or steep slopes, straw can also be held in place using plastic netting or jute. The netting shall be held in place using 11 gauge wire staples, geotextile pins or wooden stakes as described in EC-7, Geotextiles and Mats. A tackifier acts to glue the straw fibers together and to the soil surface. The tackifier , shall be selected based on longevity and ability to hold the fibers in place. A tackifier is 2 of 3 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Straw Mulch EC-6 typically applied at a rate of 125 Ib/acre. In windy conditions, the rates are typically 180 Ib/acre. Costs Average annual cost for installation and maintenance (3-4 months useful life) is $2,500 per acre. Application by hand is more time intensive and potentially costly. Inspection and Maintenance • Inspect BMPs prior to forecast rain, daily during extended rain events, after rain events, weekly during the rainy season, and at two-week intervals during the non-rainy season. • Areas where erosion is evident should be repaired and BMPs re-applied as soon as possible. Care should be exercised to minimize the damage to protected areas while making repairs, as any area damaged will require re-application of BMPs. • The key consideration in inspection and maintenance is that the straw needs to last long enough to achieve erosion control objectives. • Maintain an unbroken, temporary mulched ground cover while disturbed soil areas are inactive. Repair any damaged ground cover and re-mulch exposed areas. • Reapplication of straw mulch and tackifier may be required to maintain effective soil stabilization over disturbed areas and slopes. References Controlling Erosion of Construction Sites, Agricultural Information Bulletin #347, U.S. Department of Agriculture (USDA), Natural Resources Conservation Service (NRCS) (formerly Soil Conservation Service - SCS). Guides for Erosion and Sediment Control in California, USDA Soils Conservation Service, January 1991. Manual of Standards of Erosion and Sediment Control Measures, Association of Bay Area Governments, May 1995. Soil Erosion by Water, Agricultural Information Bulletin #513, U.S. Department of Agriculture, Soil Conservation Service. Stormwater Quality Handbooks Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Stormwater Management of the Puget Sound Basin, Technical Manual, Publication #91-75, Washington State Department of Ecology, February 1992. Water Quality Management Plan for the Lake Tahoe Region, Volume II, Handbook of Management Practices, Tahoe Regional Planning Agency, November 1988. January 2003 California Stormwater BMP Handbook 3 of 3 Construction www.cabmphandbooks.com Geotextiles and Mats EC-7 Objectives Description and Purpose Mattings of natural materials are used to cover the soil surface to reduce erosion from rainfall impact, hold soil in place, and absorb and hold moisture near the soil surface. Additionally, matting may be used to stabilize soils until vegetation is established. Suitable Applications Mattings are commonly applied on short, steep slopes where erosion hazard is high and vegetation will be slow to establish. Mattings are also used on stream banks where moving water at velocities between 3 ft/s and 6 ft/s are likely to wash out new vegetation, and in areas where the soil surface is disturbed and where existing vegetation has been removed. Matting may also be used when seeding cannot occur (e.g., late season construction and/or the arrival of an early rain season). Erosion control matting should be considered when the soils are fine grained and potentially erosive. These measures should be considered in the following situations. • Steep slopes, generally steeper than 3:1 (H:V) • Slopes where the erosion potential is high • Slopes and disturbed soils where mulch must be anchored • Disturbed areas where plants are slow to develop • Channels with flows exceeding 3.3 ft/s EC SE TC WE NS WM Erosion Control J Sediment Control Tracking Control Wind Erosion Control •/ Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: if Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives EC-3 Hydraulic Mulch EC4 Hydroseeding EC-5 Soil Binders EC-6 Straw Mulch EC-8 Wood Mulching CASQA California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 11 EC-7 Geotextiles and Mats • Channels to be vegetated ' -,,^ • Stockpiles • Slopes adjacent to water bodies of Environmentally Sensitive Areas (ESAs) Limitations • Properly installed mattings provide excellent erosion control but do so at relatively high cost. This high cost typically limits the use of mattings to areas of concentrated channel flow and steep slopes. • Mattings are more costly than other BMP practices, limiting their use to areas where other BMPs are ineffective (e.g. channels, steep slopes). • Installation is critical and requires experienced contractors. The contractor should install the matting material in such a manner that continuous contact between the material and the soil occurs. • Geotextiles and Mats may delay seed germination, due to reduction in soil temperature. • Blankets and mats are generally not suitable for excessively rocky sites or areas where the final vegetation will be mowed (since staples and netting can catch in mowers). • Blankets and mats must be removed and disposed of prior to application of permanent soil xl-_ stabilization measures. , JI, '*>**? m Plastic sheeting is easily vandalized, easily torn, photodegradable, and must be disposed of at a landfill. • Plastic results in 100% runoff, which may cause serious erosion problems in the areas receiving the increased flow. • The use of plastic should be limited to covering stockpiles or very small graded areas for short periods of time (such as through one imminent storm event) until alternative measures, such as seeding and mulching, may be installed. • Geotextiles, mats, plastic covers, and erosion control covers have maximum flow rate limitations; consult the manufacturer for proper selection. • Not suitable for areas that have heavy foot traffic (tripping hazard) - e.g., pad areas around buildings under construction. Implementation Material Selection Organic matting materials have been found to be effective where re-vegetation will be provided by re-seeding. The choice of matting should be based on the size of area, side slopes, surface conditions such as hardness, moisture, weed growth, and availability of materials. 2 of 11 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Geotextiles and Mats EC-7 The following natural and synthetic mattings are commonly used: Geotextiles m Material should be a woven polypropylene fabric with minimum thickness of 0.06 in., minimum width of 12 ft and should have minimum tensile strength of 150 Ibs (warp), 80 Ibs (fill) in conformance with the requirements in ASTM Designation: D 4632. The permittivity of the fabric should be approximately 0.07 sec-1 in conformance with the requirements in ASTM Designation: 04491. The fabric should have an ultraviolet (UV) stability of 70 percent in conformance with the requirements in ASTM designation: 04355. Geotextile blankets must be secured in place with wire staples or sandbags and by keying into tops of slopes to prevent infiltration of surface waters under geotextile. Staples should be made of minimum 11 gauge steel wire and should be U-shaped with 8 in. legs and 2 in. crown. • Geotextiles may be reused if they are suitable for the use intended. Plastic Covers m Plastic sheeting should have a minimum thickness of 6 mils, and must be keyed in at the top of slope and firmly held in place with sandbags or other weights placed no more than 10 ft apart. Seams are typically taped or weighted down their entire length, and there should be at least a 12 in. to 24 in. overlap of all seams. Edges should be embedded a minimum of 6 in. in soil. • All sheeting must be inspected periodically after installation and after significant rainstorms to check for erosion, undermining, and anchorage failure. Any failures must be repaired immediately. If washout or breakages occur, the material should be re-installed after repairing the damage to the slope. Erosion Control Blankets/Mats m Biodegradable rolled erosion control products (RECPs) are typically composed of jute fibers, curled wood fibers, straw, coconut fiber, or a combination of these materials. In order for an RECP to be considered 100% biodegradable, the netting, sewing or adhesive system that holds the biodegradable mulch fibers together must also be biodegradable. Jute is a natural fiber that is made into a yarn that is loosely woven into a biodegradable mesh. It is designed to be used in conjunction with vegetation and has longevity of approximately one year. The material is supplied in rolled strips, which should be secured to the soil with U-shaped staples or stakes in accordance with manufacturers' recommendations. Excelsior (curled wood fiber) blanket material should consist of machine produced mats of curled wood excelsior with 80 percent of the fiber 6 in. or longer. The excelsior blanket should be of consistent thickness. The wood fiber must be evenly distributed over the entire area of the blanket. The top surface of the blanket should be covered with a photodegradable extruded plastic mesh. The blanket should be smolder resistant without the use of chemical additives and should be non-toxic and non-injurious to plant and animal life. Excelsior blankets should be furnished in rolled strips, a minimum of 48 in. wide, and should have an average weight of 0.8 lb/yd2, ±10 percent, at the time of manufacture. Excelsior blankets must be secured in place with wire staples. Staples January 2003 California Stormwater BMP Handbook 3 of 11 Construction www.cabmphandbooks.com EC-7 Geotextiles and Mats should be made of minimum 11 gauge steel wire and should be U-shaped with 8 in. legs ' and 2 in. crown. Straw blanket should be machine produced mats of straw with a lightweight biodegradable netting top layer. The straw should be attached to the netting with biodegradable thread or glue strips. The straw blanket should be of consistent thickness. The straw should be evenly distributed over the entire area of the blanket. Straw blanket should be furnished in rolled strips a minimum of 6.5 ft wide, a minimum of 80 ft long and a minimum of 0.5 lb/yd2. Straw blankets must be secured in place with wire staples. Staples should be made of minimum li gauge steel wire and should be U-shaped with 8 in. legs and 2 in. crown. - Wood fiber blanket is composed of biodegradable fiber mulch with extruded plastic netting held together with adhesives. The material is designed to enhance re-vegetation. The material is furnished in rolled strips, which must be secured to the ground with U- shaped staples or stakes in accordance with manufacturers' recommendations. Coconut fiber blanket should be a machine produced mat of 100 percent coconut fiber with biodegradable netting on the top and bottom. The coconut fiber should be attached to the netting with biodegradable thread or glue strips. The coconut fiber blanket should be of consistent thickness. The coconut fiber should be evenly distributed over the entire area of the blanket. Coconut fiber blanket should be furnished in rolled strips with a minimum of 6.5 ft wide, a minimum of 80 ft. long and a minimum of 0.5 lb/yd2. Coconut fiber blankets must be secured in place with wire staples. Staples r should be made of minimum 11 gauge steel wire and should be U-shaped with 8 in. legs ( and 2 in. crown. - Coconut fiber mesh is a thin permeable membrane made from coconut or corn fiber that is spun into a yarn and woven into a biodegradable mat. It is designed to be used in conjunction with vegetation and typically has longevity of several years. The material is supplied in rolled strips, which must be secured to the soil with U-shaped staples or stakes in accordance with manufacturers' recommendations. Straw coconut fiber blanket should be machine produced mats of 70 percent straw and 30 percent coconut fiber with a biodegradable netting top layer and a biodegradable bottom net. The straw and coconut fiber should be attached to the netting with biodegradable thread or glue strips. The straw coconut fiber blanket should be of consistent thickness. The straw and coconut fiber should be evenly distributed over the entire area of the blanket. Straw coconut fiber blanket should be furnished in rolled strips a minimum of 6.5 ft wide, a minimum of 80 ft long and a minimum of 0.5 lb/yd2. Straw coconut fiber blankets must be secured in place with wire staples. Staples should be made of minimum n gauge steel wire and should be U-shaped with 8 in. legs and 2 in. crown. Non-biodegradable RECPs are typically composed of polypropylene, polyethylene, nylon or other synthetic fibers. In some cases, a combination of biodegradable and synthetic fibers is used to construct the RECP. Netting used to hold these fibers together is typically non- biodegradable as well. 4 of 11 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Geotextiles and Mats EC-7 Plastic netting is a lightweight biaxially oriented netting designed for securing loose mulches like straw or paper to soil surfaces to establish vegetation. The netting is photodegradable. The netting is supplied in rolled strips, which must be secured with U-- shaped staples or stakes in accordance with manufacturers' recommendations. Plastic mesh is an open weave geotextile that is composed of an extruded synthetic fiber woven into a mesh with an opening size of less than */4 in. It is used with re- vegetation or may be used to secure loose fiber such as straw to the ground. The material is supplied in rolled strips, which must be secured to the soil with U-shaped staples or stakes in accordance with manufacturers' recommendations. - Synthetic fiber with netting is a mat that is composed of durable synthetic fibers treated to resist chemicals and ultraviolet light. The mat is a dense, three dimensional mesh of synthetic (typically polyolefin) fibers stitched between two polypropylene nets. The mats are designed to be re-vegetated and provide a permanent composite system of soil, roots, and geomatrix. The material is furnished in rolled strips, which must be secured with U-shaped staples or stakes in accordance with manufacturers' recommendations. Bonded synthetic fibers consist of a three dimensional geomatrix nylon (or other synthetic) matting. Typically it has more than 90 percent open area, which facilitates root growth. It's tough root reinforcing system anchors vegetation and protects against hydraulic lift and shear forces created by high volume discharges. It can be installed over prepared soil, followed by seeding into the mat. Once vegetated, it becomes an invisible composite system of soil, roots, and geomatrix. The material is furnished in rolled strips that must be secured with U-shaped staples or stakes in accordance with manufacturers' recommendations. Combination synthetic and biodegradable RECPs consist of biodegradable fibers, such as wood fiber or coconut fiber, with a heavy polypropylene net stitched to the top and a high strength continuous filament geomatrix or net stitched to the bottom. The material is designed to enhance re-vegetation. The material is furnished in rolled strips, which must be secured with U-shaped staples or stakes in accordance with manufacturers' recommendations. Site Preparation • Proper site preparation is essential to ensure complete contact of the blanket or matting with the soil. • Grade and shape the area of installation. • Remove all rocks, clods, vegetation or other obstructions so that the installed blankets or mats will have complete, direct contact with the soil. • Prepare seedbed by loosening 2 to 3 in. of topsoil. Seeding Seed the area before blanket installation for erosion control and revegetation. Seeding after mat installation is often specified for turf reinforcement application. When seeding prior to blanket January 2003 California Stormwater BMP Handbook 5 of 11 Construction www.cabmphandbooks.com EC-7Geotextiles and Mats installation, all check slots and other areas disturbed during installation must be re-seeded. Where soil filling is specified, seed the matting and the entire disturbed area after installation and prior to filling the mat with soil. Fertilize and seed in accordance with seeding specifications or other types of landscaping plans. When using jute matting on a seeded area, apply approximately half the seed before laying the mat and the remainder after laying the mat. The protective matting can be laid over areas where grass has been planted and the seedlings have emerged. Where vines or other ground covers are to be planted, lay the protective matting first and then plant through matting according to design of planting. Check Slots Check slots are made of glass fiber strips, excelsior matting strips or tight folded jute matting blanket or strips for use on steep, highly erodible watercourses. The check slots are placed in narrow trenches 6 to 12 in. deep across the channel and left flush with the soil surface. They are to cover the full cross section of designed flow. Laying and Securing Matting m Before laying the matting, all check slots should be installed and the friable seedbed made free from clods, rocks, and roots. The surface should be compacted and finished according to the requirements of the manufacturer's recommendations. • Mechanical or manual lay down equipment should be capable of handling full rolls of fabric and laying the fabric smoothly without wrinkles or folds. The equipment should meet the fabric manufacturer's recommendations or equivalent standards. Anchoring • U-shaped wire staples, metal geotextile stake pins, or triangular wooden stakes can be used to anchor mats and blankets to the ground surface. • Wire staples should be made of minimum ll gauge steel wire and should be U-shaped with 8 in. legs and 2 in. crown. • Metal stake pins should be 0.188 in. diameter steel with a 1.5 in. steel washer at the head of the pin, and 8 in. in length. • Wire staples and metal stakes should be driven flush to the soil surface. Installation on Slopes Installation should be in accordance with the manufacturer's recommendations. In general, these will be as follows: • Begin at the top of the slope and anchor the blanket in a 6 in. deep by 6 in. wide trench. Backfill trench and tamp earth firmly. • Unroll blanket down slope in the direction of water flow. • Overlap the edges of adjacent parallel rolls 2 to 3 in. and staple every 3 ft. 6 of 11 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com 3 Geotextiles and Mats EC-7 • When blankets must be spliced, place blankets end over end (shingle style) with 6 in. overlap. Staple through overlapped area, approximately 12 in. apart. • Lay blankets loosely and maintain direct contact with the soil. Do not stretch. • Staple blankets sufficiently to anchor blanket and maintain contact with the soil. Staples should be placed down the center and staggered with the staples placed along the edges. Steep slopes, 1:1 (H:V) to 2:1 (H:V), require a minimum of 2 staples/yd2. Moderate slopes, 2:1 (H:\0 to 3:1 (H:V), require a minimum of i x/2 staples/yd2. Installation in Channels Installation should be in accordance with the manufacturer's recommendations. In general, these will be as follows: • Dig initial anchor trench 12 in. deep and 6 in. wide across the channel at the lower end of the project area. • Excavate intermittent check slots, 6 in. deep and 6 in. wide across the channel at 25 to 30 ft intervals along the channels. • Cut longitudinal channel anchor trenches 4 in. deep and 4 in. wide along each side of the installation to bury edges of matting, whenever possible extend matting 2 to 3 in. above the crest of the channel side slopes. • Beginning at the downstream end and in the center of the channel, place the initial end of the first roll in the anchor trench and secure with fastening devices at 12 in. intervals. Note: matting will initially be upside down in anchor trench. • In the same manner, position adjacent rolls in anchor trench, overlapping the preceding roll a minimum of 3 in. • Secure these initial ends of mats with anchors at 12 in. intervals, backfill and compact soil. • Unroll center strip of matting upstream. Stop at next check slot or terminal anchor trench. Unroll adjacent mats upstream in similar fashion, maintaining a 3 in. overlap. • Fold and secure all rolls of matting snugly into all transverse check slots. Lay mat in the bottom of the slot then fold back against itself. Anchor through both layers of mat at 12 in. intervals, then backfill and compact soil. Continue rolling all mat widths upstream to the next check slot or terminal anchor trench. • Alternate method for non-critical installations: Place two rows of anchors on 6 in. centers at 25 to 30 ft. intervals in lieu of excavated check slots. • Staple shingled lap spliced ends a minimum of 12 in. apart on 12 in. intervals. • Place edges of outside mats in previously excavated longitudinal slots; anchor using prescribed staple pattern, backfill, and compact soil. • Anchor, fill, and compact upstream end of mat in a 12 in. by 6 in. terminal trench. January 2003 California Stormwater BMP Handbook 7 of 11 Construction www.cabmphandbooks.com EC-7 Geotextiles and Mats • Secure mat to ground surface using U-shaped wire staples, geotextile pins, or wooden stakes. • Seed and fill turf reinforcement matting with soil, if specified. Soil Filling (if specified for turf reinforcement) • Always consult the manufacturer's recommendations for installation. • Do not drive tracked or heavy equipment over mat. • Avoid any traffic over matting if loose or wet soil conditions exist. • Use shovels, rakes, or brooms for fine grading and touch up. • Smooth out soil filling just exposing top netting of mat. Temporary Soil Stabilization Removal • Temporary soil stabilization removed from the site of the work must be disposed of if necessary. Costs Relatively high compared to other BMPs. Biodegradable materials: $0.50 - $o.57/yd2. Permanent materials: $3.00 - $4.5O/yd2. Staples: $0.04 - $o.os/staple. Approximate costs for installed materials are shown below: ( s Rolled Erosion Control Products Biodegradable Non-Biodegradable Jute Mesh Curled Wood Fiber Straw Wood Fiber Coconut Fiber Coconut Fiber Mesh Straw Coconut Fiber Plastic Netting Plastic Mesh Synthetic Fiber with Netting Bonded Synthetic Fibers Combination with Biodegradable Installed Cost per Acre $6,500 $10,500 $8,900 $8,900 $13,000 $31,200 $10,900 $2,000 $3,200 $34,800 $50,000 $32,000 o Source: Caltrans Guidance for Soil Stabilization for Temporary Slopes, Nov. 1999 Inspection and Maintenance • Inspect BMPs prior to forecast rain, daily during extended rain events, after rain events, weekly during the rainy season, and at two-week intervals during the non-rainy season, and at two-week intervals during the non-rainy season. • Inspect BMPs subject to non-stormwater discharges daily while non-stormwater discharges occur. 8 of 11 California Stormwater BMP Handbook Construction www.cabmphandbooks.com January 2003 Geotextiles and Mats EC-7 • Areas where erosion is evident shall be repaired and BMPs reapplied as soon as possible. Care should be exercised to minimize the damage to protected areas while making repairs, as any area damaged will require reapplication of BMPs. • If washout or breakage occurs, re-install the material after repairing the damage to the slope or channel. • Make sure matting is uniformly in contact with the soil. • Check that all the lap joints are secure. • Check that staples are flush with the ground. • Check that disturbed areas are seeded. References Guides for Erosion and Sediment Controls in California, USDA Soils Conservation Service, January 1991. National Management Measures to Control Nonpoint Source Pollution from Urban Areas, United States Environmental Protection Agency, 2002. Stormwater Quality Handbooks Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Guidance Document: Soil Stabilization for Temporary Slopes, State of California Department of Transportation (Caltrans), November 1999 Stormwater Management of the Puget Sound Basin, Technical Manual, Publication #91-75, Washington State Department of Ecology, February 1992. Water Quality Management Plan for The Lake Tahoe Region, Volume II, Handbook of Management Practices, Tahoe Regional Planning Agency, November 1988. January 2003 California Stormwater BMP Handbook 9 of 11 Construction www.cabmphandbooks.com EC-7 Geotextiles and Mats 6" X 6"anchor trench Mats/blankets should be installed vertically downslope. 2", to 3" overlap./ ISOMETRIC VIEW TYPICAL SLOPE SOIL STABLIZATION NOTES: — woven geotextile filter fabric under typical treatment. WET SLOPE LINING NTS 1. Slope surface shall b'e free of rocks, clods, sticks and grass. Mats/blankets shall have good soil contact. 2. Lay blankets loosely and stake or staple to maintain direct contact with the soil. Do not stretch. 3. Install per manufacturer's recommendations TYPICAL INSTALLATION DETAIL 10 of 11 California Stormwater BMP Handbook Construction www.cabmphandbooks.com January 2003 Geotextiles and Mats EC-7 INITIAL CHANNEL ANCHOR TRENCH NTS Stake at 3' to 5' intervals TERMINAL SLOPE AND CHANNEL ANCHOR TRENCH NTS Check slot at 25'-30' intervals ISOMETRIC VIEW NTS r4" X 4" anchor shoe 4"- LONGITUDINAL ANCHOR TRENCH NTS INTERMITTENT CHECK SLOT NTS NOTES: 1. Check slots to be constructed per manufacturers specifications. 2. Staking or stapling layout per manufacturers specifications. 3. Install per manufacturer's recommendations TYPICAL INSTALLATION DETAIL January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 11 of 11 Wood Mulching EC-8 Description and Purpose Wood mulching consist of applying a mixture of shredded wood mulch, bark or compost to disturbed soils. The primary function of wood mulching is to reduce erosion by protecting bare soil from rainfall impact, increasing infiltration, and reducing runoff. Suitable Applications Wood mulching is suitable for disturbed soil areas requiring temporary protection until permanent stabilization is established. Limitations • Not suitable for use on slopes steeper than 3:1 (H:V). Best suited to flat areas or gentle slopes or 5:1 (H:V) or flatter. • Wood mulch and compost may introduce unwanted species. • Not suitable for areas exposed to concentrated flows. • May need to be removed prior to further earthwork. Implementation Mulch Selection There are many types of mulches. Selection of the appropriate type of mulch should be based on the type of application, site conditions, and compatibility with planned or future uses. AppZication Procedures Prior to application, after existing vegetation has been removed, roughen embankment and fill areas by rolling with a device such as Objectives EC SE TC WE NS WM Erosion Control J Sediment Control Tracking Control Wind Erosion Control / Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: v Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives EC-3 Hydraulic Mulch EC-4 Hydroseeding EC-5 Soil Binders EC-6 Straw Mulch EC-7 Geotextiles and Mats CASQA California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 3 EC-8 Wood Mulching a punching type roller or by track walking. The construction application procedures for mulches ( '**"**' vary significantly depending upon the type of mulching method specified. Two methods are highlighted here: • Green Material: This type of mulch is produced by the recycling of vegetation trimmings such as grass, shredded shrubs, and trees. Methods of application are generally by hand although pneumatic methods are available. Green material can be used as a temporary ground cover with or without seeding. - The green material should be evenly distributed on site to a depth of not more than 2 in. • Shredded Wood: Suitable for ground cover in ornamental or revegetated plantings. Shredded wood/bark is conditionally suitable. See note under limitations. Distribute by hand or use pneumatic methods. Evenly distribute the mulch across the soil surface to a depth of 2 to 3 in. • Avoid mulch placement onto .roads, sidewalks, drainage channels, existing vegetation, etc. Costs Average annual cost for installation and maintenance (3-4 months useful life) is around $4,000 per acre, but cost can increase if the source is not close to the project site. / Inspection and Maintenance • Inspect BMPs prior to forecast rain, daily during extended rain events, after rain events, weekly during the rainy season, and at two-week intervals during the non-rainy season. • Areas where erosion is evident shall be repaired and BMPs reapplied as soon as possible. Care should be exercised to minimize the damage to protected areas while making repairs, as any area damaged will require reapplication of BMPs. • Regardless of the mulching technique selected, the key consideration in inspection and maintenance is that the mulch needs to last long enough to achieve erosion control objectives. If the mulch is applied as a stand alone erosion control method over disturbed areas (without seed), it should last the length of time the site will remain barren or until final re-grading and revegetation. • Where vegetation is not the ultimate cover, such as ornamental and landscape applications of bark or wood chips, inspection and maintenance should focus on longevity and integrity of the mulch. • Reapply mulch when bare earth becomes visible. References Controlling Erosion of Construction Sites Agriculture Information Bulletin #347, U.S. Department of Agriculture (USDA), Natural Resources Conservation Service (NRCS) (formerly Soil Conservation Service - SCS). ( 2 of 3 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Wood Mulching EC-8 Guides for Erosion and Sediment Control in California, USDA Soils Conservation Service, January 1991. Manual of Standards of Erosion and Sediment Control Measures, Association of Bay Area Governments, May 1995. Proposed Guidance Specifying Management Measures for Sources of Nonpoint Pollution in Coastal Waters, Work Group Working Paper, USEPA, April 1992. Sedimentation and Erosion Control, An Inventory of Current Practices Draft, U.S. EPA, April 1990. Soil Erosion by Water Agricultural Information Bulletin #513, U.S. Department of Agriculture, Soil Conservation Service. Stormwater Quality Handbooks Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Water Quality Management Plan for the Lake Tahoe Region, Volume II, Handbook of Management Practices, Tahoe Regional Planning Agency, November 1988. January 2003 California Stormwater BMP Handbook 3 of 3 Construction www.cabmphandbooks.com Earth Dikes and Drainage Swales EC-9 Description and Purpose An earth dike is a temporary berm or ridge of compacted soil used to divert runoff or channel water to a desired location. A drainage swale is a shaped and sloped depression in the soil surface used to convey runoff to a desired location. Earth dikes and drainage swales are used to divert off site runoff around the construction site, divert runoff from stabilized areas and disturbed areas, and direct runoff into sediment basins or traps. Suitable Applications Earth dikes and drainage swales are suitable for use, individually or together, where runoff needs to be diverted from one area and conveyed to another. • Earth dikes and drainage swales may be used: - To convey surface runoff down sloping land To intercept and divert runoff to avoid sheet flow over sloped surfaces To divert and direct runoff towards a stabilized watercourse, drainage pipe or channel To intercept runoff from paved surfaces - Below steep grades where runoff begins to concentrate - Along roadways and facility improvements subject to flood drainage Objectives EC SE TC WE NS WM Erosion Control •/ Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: */ Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives None CASQA llfornia Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 7 EC-9 Earth Dikes and Drainage Swales At the top of slopes to divert runon from adjacent or undisturbed slopes - At bottom and mid slope locations to intercept sheet flow and convey concentrated flows - Divert sediment laden runoff into sediment basins or traps Limitations Dikes should not be used for drainage areas greater than 10 acres or along slopes greater than 10 percent. For larger areas more permanent drainage structures should be built. All drainage structures should be built in compliance with local municipal requirements. • Earth dikes may create more disturbed area on site and become barriers to construction equipment. • Earth dikes must be stabilized immediately, which adds cost and maintenance concerns. • Diverted stormwater may cause downstream flood damage. • Dikes should not be constructed of soils that may be easily eroded. • Regrading the site to remove the dike may add additional cost. • Temporary drains and swales or any other diversion of runoff should not adversely impact upstream or downstream properties. • Temporary drains and swales must conform to local floodplain management requirements. • Earth dikes/drainage swales are not suitable as sediment trapping devices. • It may be necessary to use other soil stabilization and sediment controls such as check dams, plastics, and blankets, to prevent scour and erosion in newly graded dikes, swales, and ditches. Implementation The temporary earth dike is a berm or ridge of compacted soil, located in such a manner as to divert stormwater to a sediment trapping device or a stabilized outlet, thereby reducing the potential for erosion and offsite sedimentation. Earth dikes can also be used to divert runoff from off site and from undisturbed areas away from disturbed areas and to divert sheet flows away from unprotected slopes. An earth dike does not itself control erosion or remove sediment from runoff. A dike prevents erosion by directing runoff to an erosion control device such as a sediment trap or directing runoff away from an erodible area. Temporary diversion dikes should not adversely impact adjacent properties and must conform to local floodplain management regulations, and should not be used in areas with slopes steeper than 10%. Slopes that are formed during cut and fill operations should be protected from erosion by runoff. A combination of a temporary drainage swale and an earth dike at the top of a slope can divert runoff to a location where it can be brought to the bottom of the slope (see EC-n, Slope Drains). A combination dike and swale is easily constructed by a single pass of a bulldozer or grader and 2 of 7 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Earth Dikes and Drainage Swales EC-9 compacted by a second pass of the tracks or wheels over the ridge. Diversion structures should be installed when the site is initially graded and remain in place until post construction BMPs are installed and the slopes are stabilized. Diversion practices concentrate surface runoff, increasing its velocity and erosive force. Thus, the flow out of the drain or swale must be directed onto a stabilized area or into a grade stabilization structure. If significant erosion will occur, a swale should be stabilized using vegetation, chemical treatment, rock rip-rap, matting, or other physical means of stabilization. Any drain or swale that conveys sediment laden runoff must be diverted into a sediment basin or trap before it is discharged from the site. General m Care must be applied to correctly size and locate earth dikes, drainage swales. Excessively steep, unlined dikes, and swales are subject to erosion and gully formation. • Conveyances should be stabilized. • Use a lined ditch for high flow velocities. • Select flow velocity based on careful evaluation of the risks due to erosion of the measure, soil types, overtopping, flow backups, washout, and drainage flow patterns for each project site. • Compact any fills to prevent unequal settlement. • Do not divert runoff onto other property without securing written authorization from the property owner. • When possible, install and utilize permanent dikes, swales, and ditches early in the construction process. • Provide stabilized outlets. Earth Dikes Temporary earth dikes are a practical, inexpensive BMP used to divert stormwater runoff. Temporary diversion dikes should be installed in the following manner: • All dikes should be compacted by earth moving equipment. • All dikes should have positive drainage to an outlet. • All dikes should have 2:1 or flatter side slopes, 18 in. minimum height, and a minimum top width of 24 in. Wide top widths and flat slopes are usually needed at crossings for construction traffic. • The outlet from the earth dike must function with a minimum of erosion. Runoff should be conveyed to a sediment trapping device such as a Sediment Trap (SE-3) or Sediment Basin (SE-2) when either the dike channel or the drainage area above the dike are not adequately stabilized. January 2003 California Stormwater BMP Handbook 3 of 7 Construction www.cabmphandbooks.com EC-9 Earth Dikes and Drainage Swales • Temporary stabilization may be achieved using seed and mulching for slopes less than 5% and either rip-rap or sod for slopes in excess of 5%. In either case, stabilization of the earth dike should be completed immediately after construction or prior to the first rain. • If riprap is used to stabilize the channel formed along the toe of the dike, the following typical specifications apply: Channel Grade 0.5-1.0% 1.1-2.0% 2.1-4.0% 4.1-5.0% Riprap Stabilization 4 in. Rock 6 in. Rock 8 in. Rock 8 in. -12 in. Riprap • The stone riprap, recycled concrete, etc. used for stabilization should be pressed into the soil with construction equipment. • Filter cloth may be used to cover dikes in use for long periods. • Construction activity on the earth dike should be kept to a minimum. Drainage Sivales Drainage swales are only effective if they are properly installed. Swales are more effective than dikes because they tend to be more stable. The combination of a swale with a dike on the downhill side is the most cost effective diversion. Standard engineering design criteria for small open channel and closed conveyance systems should be used (see the local drainage design manual). Unless local drainage design criteria state otherwise, drainage swales should be designed as follows: • No more than 5 acres may drain to a temporary drainage swale. » Place drainage swales above or below, not on, a cut or fill slope. • Swale bottom width should be at least 2 ft » Depth of the swale should be at least 18 in. • Side slopes should be 2:1 or flatter. • Drainage or swales should be laid at a grade of at least i percent, but not more than 15 percent. • The swale must not be overtopped by the peak discharge from a lo-year storm, irrespective of the design criteria stated above. • Remove all trees, stumps, obstructions, and other objectionable material from the swale when it is built. • Compact any fill material along the path of the swale. 4 of 7 California Stormwater BMP Handbook Construction www.cabmphandbooks.com January 2003 Earth Dikes and Drainage Swales EC-9 • Stabilize all swales immediately. Seed and mulch swales at a slope of less than 5 percent, and use rip-rap or sod for swales with a slope between 5 and 15 percent. For temporary swales, geotextiles and mats (EC-7) may provide immediate stabilization. • Irrigation may be required to establish sufficient vegetation to prevent erosion. • Do not operate construction vehicles across a swale unless a stabilized crossing is provided. • Permanent drainage facilities must be designed by a professional engineer (see the local drainage design criteria for proper design). • At a minimum, the drainage swale should conform to predevelopment drainage patterns and capacities. • Construct the drainage swale with a positive grade to a stabilized outlet. • Provide erosion protection or energy dissipation measures if the flow out of the drainage swale can reach an erosive velocity. Costs • Cost ranges from $15 to $55 per ft for both earthwork and stabilization and depends on availability of material, site location, and access. • Small dikes: $2.50 - $6.so/linear ft; Large dikes: $2.so/yd3. • The cost of a drainage swale increases with drainage area and slope. Typical swales for controlling internal erosion are inexpensive, as they are quickly formed during routine earthwork. Inspection and Maintenance • Inspect BMPs prior to forecast rain, daily during extended rain events, after rain events, weekly during the rainy season, and at two-week intervals during the non-rainy season. • Inspect BMPs subject to non-stormwater discharges daily while non-stormwater discharges occur. • Inspect ditches and berms for washouts. Replace lost riprap, damaged linings or soil stabilizers as needed. • Inspect channel linings, embankments, and beds of ditches and berms for erosion and accumulation of debris and sediment. Remove debris and sediment and repair linings and embankments as needed. • Temporary conveyances should be completely removed as soon as the surrounding drainage area has been stabilized or at the completion of construction References Erosion and Sediment Control Handbook, S.J. Goldman, K. Jackson, T.A. Bursetynsky, P.E., McGraw Hill Book Company, 1986. January 2003 California Stormwater BMP Handbook 5 of 7 Construction www.cabmphandbooks.com EC-9 Earth Dikes and Drainage Swales Manual of Standards of Erosion and Sediment Control Measures, Association of Bay Area Governments, May 1995. National Association of Home Builders (NAHB). Stormwater Runoff & Nonpoint Source Pollution Control Guide for Builders and Developers. National Association of Home Builders, Washington, D.C., 1995 National Management Measures to Control Nonpoint Source Pollution from Urban Areas, United States Environmental Protection Agency, 2002. Southeastern Wisconsin Regional Planning Commission (SWRPC). Costs of Urban Nonpoint Source Water Pollution Control Measures. Technical Report No. 31. Southeastern Wisconsin Regional Planning Commission, Waukesha, WL 1991 Stormwater Quality Handbooks Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Stormwater Management of the Puget Sound Basin, Technical Manual, Publication #91-75, Washington State Department of Ecology, February 1992. Water Quality Management Plan for the Lake Tahoe Region, Volume II, Handbook of Management Practices, Tahoe Regional Planning Agency, November 1988. 6 of 7 California Stormwater BMP Handbook Construction www.cabmphandbooks.com January 2003 Earth Dikes and Drainage Swales EC-9 24" Compacted fill Stabilizing cover, when needed. Natural ground line 2:1 (H: V) slope or flatter TYPICAL DRAINAGE SWALE NOT TO SCALE NOTES: 1. Stabilize inlet, outlets and slopes. 2. Properly compact the subgrade. 24"Stabilizing cover, when needed Compacted fill Natural ground line TYPICAL EARTH DIKE NOT TO SCALE January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 7 of 7 Velocity Dissipation Devices EC-10 Description and Purpose Outlet protection is a physical device composed of rock, grouted riprap, or concrete rubble, which is placed at the outlet of a pipe or channel to prevent scour of the soil caused by concentrated, high velocity flows. Suitable Applications Whenever discharge velocities and energies at the outlets of culverts, conduits, or channels are sufficient to erode the next downstream reach. This includes temporary diversion structures to divert runon during construction. • These devices may be used at the following locations: Outlets of pipes, drains, culverts, slope drains, diversion ditches, swales, conduits, or channels. - Outlets located at the bottom of mild to steep slopes. Discharge outlets that carry continuous flows of water. - Outlets subject to short, intense flows of water, such as flash floods. Points where lined conveyances discharge to unlined conveyances Limitations • Large storms or high flows can wash away the rock outlet protection and leave the area susceptible to erosion. Objectives EC SE TC WE NS Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control .._,, Waste Management and Materials Pollution Control Legend: J Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives None ASQA [California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 4 EC-10 Velocity Dissipation Devices • Sediment captured by the rock outlet protection may be difficult to remove without removing the rock. ' • Outlet protection may negatively impact the channel habitat. • Grouted riprap may break up in areas of freeze and thaw. • If there is not adequate drainage, and water builds up behind grouted riprap, it may cause the grouted riprap to break up due to the resulting hydrostatic pressure. Implementation General Outlet protection is needed where discharge velocities and energies at the outlets of culverts, conduits or channels are sufficient to erode the immediate downstream reach. This practice protects the outlet from developing small eroded pools (plange pools), and protects against gully erosion resulting from scouring at a culvert mouth. Design and Layout As with most channel design projects, depth of flow, roughness, gradient, side slopes, discharge rate, and velocity should be considered in the outlet design. Compliance to local and state regulations should also be considered while working in environmentally sensitive streambeds. General recommendations for rock size and length of outlet protection mat are shown in the rock outlet protection figure in this BMP and should be considered minimums. The apron length and rock size gradation are determined using a combination of the discharge pipe ^^ diameter and estimate discharge rate: Select the longest apron length and largest rock size ^^J suggested by the pipe size and discharge rate. Where flows are conveyed in open channels such ( as ditches and swales, use the estimated discharge rate for selecting the apron length and rock size. Flows should be same as the culvert or channel design flow but never the less than the peak 5 year flow for temporary structures planned for one rainy season, or the 10 year peak flow for temporary structures planned for two or three rainy seasons. • There are many types of energy dissipaters, with rock being the one that is represented in the attached figure. • Best results are obtained when sound, durable, and angular rock is used. • Install riprap, grouted riprap, or concrete apron at selected outlet. Riprap aprons are best suited for temporary use during construction. Grouted or wired tied rock riprap can minimize maintenance requirements. • Rock outlet protection is usually less expensive and easier to install than concrete aprons or energy dissipaters. It also serves to trap sediment and reduce flow velocities. • Carefully place riprap to avoid damaging the filter fabric. Stone 4 in. to 6 in. may be carefully dumped onto filter fabric from a height not to exceed 12 in. Stone 8 in. to 12 in. must be hand placed onto filter fabric, or the filter fabric may be "•"% covered with 4 in. of gravel and the 8 in. to 12 in. rock may be dumped from a height not ^^ to exceed 16 in. ' 2 of 4 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Velocity Dissipation Devices EC-10 Stone greater than 12 in. shall only be dumped onto filter fabric protected with a layer of gravel with a thickness equal to one half the D50 rock size, and the dump height limited to twice the depth of the gravel protection layer thickness. • For proper operation of apron: Align apron with receiving stream and keep straight throughout its length. If a curve is needed to fit site conditions, place it in upper section of apron. • Outlets on slopes steeper than 10 percent should have additional protection. Costs Costs are low if material is readily available. If material is imported, costs will be higher. Average installed cost is $150 per device. Inspection and Maintenance • Inspect BMPs prior to forecast rain, daily during extended rain events, after rain events, weekly during the rainy season, and at two-week intervals during the non-rainy season. • Inspect BMPs subjected to non-stormwater discharges daily while non-stormwater discharges occur. • Inspect apron for displacement of the riprap and damage to the underlying fabric. Repair fabric and replace riprap that has washed away. If riprap continues to wash away, consider using larger material. • Inspect for scour beneath the riprap and around the outlet. Repair damage to slopes or underlying filter fabric immediately. • Temporary devices should be completely removed as soon as the surrounding drainage area has been stabilized or at the completion of construction. References County of Sacramento Improvement Standards, Sacramento County, May 1989. Erosion and Sediment Control Handbook, S.J. Goldman, K. Jackson, T.A. Bursztynsky, P.E., McGraw Hill Book Company, 1986. Handbook of Steel Drainage & Highway Construction, American Iron and Steel Institute, 1983. Manual of Standards of Erosion and Sediment Control Measures, Association of Bay Area Governments, May 1995. Stormwater Quality Handbooks Construction Site Best Management Practices (BMPs) Manual, state of California Department of Transportation (Caltrans), November 2000. Stormwater Management of the Puget Sound Basin, Technical Manual, Publication #91-75, Washington State Department of Ecology, February 1992. Water Quality Management Plan for the Lake Tahoe Region, Volume II, Handbook of Management Practices, Tahoe Regional Planning Agency, November 1988. January 2003 California Stormwater BMP Handbook 3 of 4 Construction www.cabmphandbooks.com EC-10 Velocity Dissipation Devices 4d0 (min) Pipe outlet to well defined channel PLAN VIEW Filter Fabric- SECTION A-A Key in 6"-9" recommended for entire perimeter rd=1.5 Max rock dia. 3 Pipe Diameter inches 12 18 24 Discharge fts/s 5 10 10 20 30 40 30 40 50 60 Apron Length, La ft 10 13 10 16 23 26 16 26 26 30 Rip Rap DSo Diameter Min inches 4 6 6 8 12 16 8 8 12 16 For larger or higher flows consult a Registered Civil Engineer Source: USDA-SCS o 4 of 4 California Stormwater BMP Handbook Construction www.cabmphandbooks.com January 2003 Slope Drains EC-11 Description and Purpose A slope drain is a pipe used to intercept and direct surface runoff or groundwater into a stabilized watercourse, trapping device, or stabilized area. Slope drains are used with earth dikes and drainage ditches to intercept and direct surface flow away from slope areas to protect cut or fill slopes. Suitable Applications • Where concentrated flow of surface runoff must be conveyed down a slope in order to prevent erosion. • Drainage for top of slope diversion dikes or swales. • Drainage for top of cut and fill slopes where water can accumulate. • Emergency spillway for a sediment basin. Limitations Installation is critical for effective use of the pipe slope drain to minimize potential gully erosion. • Maximum drainage area per slope drain is 10 acres. (For large areas use a paved chute, rock lined channel, or additional pipes.) • Severe erosion may result when slope drains fail by overtopping, piping, or pipe separation. Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control y Legend: vf Primary Objective J Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives EC-9 Earth Dike, Drainage Swales Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 7 EC-11 _ Slope Drains - During large storms, pipe slope drains may become clogged or over charged, forcing water around the pipe and causing extreme slope erosion. If the sectional downdrain is not sized correctly, the runoff can spill over the drain sides causing gully erosion and potential failure of the structure. • Dissipation of high flow velocities at the pipe outlet is required to avoid downstream erosion. Implementation General The slope drain is applicable for any construction site where concentrated surface runoff can accumulate and must be conveyed down the slope in order to prevent erosion. The slope drain is effective because it prevents the stormwater from flowing directly down the slope by confining all the runoff into an enclosed pipe or channel. Due to the time lag between grading slopes and installation of permanent stormwater collection systems and slope stabilization measures, temporary provisions to intercept runoff are sometimes necessary. Particularly in steep terrain, slope drains can protect unstabilized areas from erosion. Installation The slope drain may be a rigid pipe, such as corrugated metal, a flexible conduit, or a lined terrace drain with the inlet placed on the top of a slope and the outlet at the bottom of the slope. This BMP typically is used in combination with a diversion control, such as an earth dike or drainage swale at the top of the slope. The following criteria must be considered when siting slope drains. • Permanent structures included in the project plans can often serve as construction BMPs if implemented early. However, the permanent structure must meet or exceed the criteria for the temporary structure. • Inlet structures must be securely entrenched and compacted to avoid severe gully erosion. » Slope drains must be securely anchored to the slope and must be adequately sized to carry the capacity of the design storm and associated forces. • Outlets must be stabilized with riprap, concrete or other type of energy dissipator, or directed into a stable sediment trap or basin. See EC-io, Velocity Dissipation Devices. • Debris racks are recommended at the inlet. Debris racks located several feet upstream of the inlet can usually be larger than racks at the inlet, and thus provide enhanced debris protection and less plugging. • Safety racks are also recommended at the inlet and outlet of pipes where children or animals could become entrapped. • Secure inlet and surround with dikes to prevent gully erosion and anchor pipe to slope. • When using slope drains, limit drainage area to 10 acres per pipe. For larger areas, use a rock lined channel or a series of pipes. 2 of 7 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Slope Drains EC-11 • Size to convey at least the peak flow of a lO-year storm. The design storm is conservative due to the potential impact of system failures. • Maximum slope generally limited to 2:1 (H:V) as energy dissipation below steeper slopes is difficult. • Direct surface runoff to slope drains with interceptor dikes. See BMP EC-g, Earth Dikes and Drainage Swales. Top of interceptor dikes should be 12 in. higher than the top of the slope drain. • Slope drains can be placed on or buried underneath the slope surface. • Recommended materials include both metal and plastic pipe, either corrugated or smooth wall. Concrete pipe can also be used. • When installing slope drains: Install slope drains perpendicular to slope contours. Compact soil around and under entrance, outlet, and along length of pipe. Securely anchor and stabilize pipe and appurtenances into soil. Check to ensure that pipe connections are watertight. - Protect area around inlet with filter cloth. Protect outlet with riprap or other energy dissipation device. For high energy discharges, reinforce riprap with concrete or use reinforced concrete device. Protect outlet of slope drains using a flared end section when outlet discharges to a flexible energy dissipation device. A flared end section installed at the inlet will improve flow into the slope drain and prevent erosion at the pipe entrance. Use a flared end section with a 6 in. minimum toe plate to help prevent undercutting. The flared section should slope towards the pipe inlet. Design and Layout The capacity for temporary drains should be sufficient to convey at least the peak runoff from a lo-year rainfall event. The pipe size may be computed using the Rational Method or a method established by the local municipality. Higher flows must be safely stored or routed to prevent any offsite concentration of flow and any erosion of the slope. The design storm is purposely conservative due to the potential impacts associated with system failures. As a guide, temporary pipe slope drains should not be sized smaller than shown in the following table: January 2003 California Stormwater BMP Handbook 3 of 7 Construction www.cabmphandbooks.com EC-11 Slope Drains Minimum Pipe Diameter (Inches) 12 18 21 24 30 Maximum Drainage Area (Acres) 1.0 3-0 5-0 7-0 1O.O Larger drainage areas can be treated if the area can be subdivided into areas of 10 acres or less and each area is treated as a separate drainage. Drainage areas exceeding 10 acres must be designed by a Registered Civil Engineer and approved by the agency that issued the grading permit. Materials: Soil type, rainfall patterns, construction schedule, local requirements, and available supply are some of the factors to be considered when selecting materials. The following types of slope drains are commonly used: • Rigid Pipe: This type of slope drain is also known as a pipe drop. The pipe usually consists of corrugated metal pipe or rigid plastic pipe. The pipe is placed on undisturbed or compacted soil and secured onto the slope surface or buried in a trench. Concrete thrust blocks must be used when warranted by the calculated thrust forces. Collars should be properly installed and secured with metal strappings or watertight collars. • Flexible Pipe: The flexible pipe slope drain consists of a flexible tube of heavy duty plastic, rubber, or composite material. The tube material is securely anchored onto the slope surface. The tube should be securely fastened to the metal inlet and outlet conduit sections with metal strappings or watertight collars. • Section Downdrains: The section downdrain consists of pre-fabricated, section conduit of half round or third round material. The sectional downdrain performs similar to a flume or chute. The pipe must be placed on undisturbed or compacted soil and secured into the slope. • Concrete-lined Terrace Drain: This is a concrete channel for draining water from a terrace on a slope to the next level. These drains are typically specified as permanent structures and if installed early, can serve as slope drains during construction, which should be designed according to local drainage design criteria. Costs • Cost varies based on pipe selection and selected outlet protection. o 4 of 7 California Stormwater BMP Handbook Construction www.cabmphandbooks.com January 2003 Slope Drains EC-11 Corrugated Steel Pipes, Per Foot Size 12" 15" 18" 24" 30" Supplied and Installed Cost (No Trenching Included) $19.60 per LF $22.00 $26.00 $32.00 $50.00 PVC Pipes, Per Foot Size 12" 14" 16" 18" 20" 24" 30" Supplied and Installed Cost (No Trenching Included) $24.50 $49.00 $51.00 $54-00 $66.00 $93-00 $130.00 Inspection and Maintenance • Inspect BMPs prior to forecast rain, daily during extended rain events, after rain events, weekly during the rainy season, and at two-week intervals during the non-rainy season. • Inspect BMPs subjected to non-stormwater discharges daily while non-stormwater discharges occur. • Inspect outlet for erosion and downstream scour. If eroded, repair damage and install additional energy dissipation measures. If downstream scour is occurring, it may be necessary to reduce flows being discharged into the channel unless other preventative measures are implemented. • Insert inlet for clogging or undercutting. Remove debris from inlet to maintain flows. Repair undercutting at inlet and if needed, install flared section or rip rap around the inlet to prevent further undercutting. • Inspect pipes for leakage. Repair leaks and restore damaged slopes. • Inspect slope drainage for accumulations of debris and sediment. • Remove built up sediment from entrances and outlets as required. Flush drains if necessary; capture and settle out sediment from discharge. January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 5 of 7 EO11 Slope Drains • Make sure water is not ponding onto inappropriate areas (e.g., active traffic lanes, material storage areas, etc.). • Pipe anchors must be checked to ensure that the pipe remains anchored to the slope. Install additional anchors if pipe movement is detected. References Draft - Sedimentation and Erosion Control, An Inventory of Current Practices, U.S.E.P.A., April 1990. National Association of Home Builders (NAHB). Stormwater Runoff & Nonpoint Source Pollution Control Guide for Builders and Developers. National Association of Home Builders, Washington, D.C., 1995 National Management Measures to Control Nonpoint Source Pollution from Urban Areas, United States Environmental Protection Agency, 2002. Stormwater Quality Handbooks Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Stormwater Management of the Puget Sound Basin, Technical Manual, Publication #91-75, Washington State Department of Ecology, February 1992. Water Quality Management Plan for the Lake Tahoe Region, Volume II, Handbook of Management Practices, Tahoe Regional Planning Agency, November 1988. 6 of 7 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Slope Drains EC-11 Earthen dike (compacted) Waterproof seal, Typical © joints Securely anchored to slope. Min Geotextile fabric D + 12' Flared end section TYPICAL SLOPE DRAIN NOT TO SCALE January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 7 of 7 Stream bank Stabilization EC-12 Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: S Primary Objective / Secondary Objective Description and Purpose Stream channels, streambanks, and associated riparian areas are dynamic and sensitive ecosystems that respond to changes in land use activity. Streambank and channel disturbance resulting from construction activities can increase the stream's sediment load, which can cause channel erosion or sedimentation and have adverse affects on the biotic system. BMPs can reduce the discharge of sediment and other pollutants to minimize the impact of construction activities on watercourses. Streams on the 3O3(d) list and listed for sediment may require numerous measures to prevent any increases in sediment load to the stream. Suitable Applications These procedures typically apply to all construction projects that disturb or occur within stream channels and their associated riparian areas. Limitations Specific permit requirements or mitigation measures such as Regional Water Quality Control Board (RWQCB) 401 Certification, U.S. Army Corps of Engineers 404 permit and approval by California Department of Fish and Game supercede the guidance in this BMP. • If numerical based water quality standards are mentioned in any of these and other related permits, testing and sampling may be required. Streams listed as 3O3(d) impaired for sediment, silt, or turbidity, are required to conduct sampling to Targeted Constituents Sediment Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives Combination of erosion and sediment controls. ASQA Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com lof 10 EC-12 Stream bank Stabilization verify that there is no net increase in sediment load due to construction activities. ( "***"' Implementation Planning • Proper planning, design, and construction techniques can minimize impacts normally associated with in stream construction activities. Poor planning can adversely affect soil, fish, wildlife resources, land uses, or land users. Planning should take into account: scheduling; avoidance of in-stream construction; minimizing disturbance area and construction time period; using pre-disturbed areas; selecting crossing location; and selecting equipment. Scheduling m Construction activities should be scheduled according to the relative sensitivity of the environmental concerns and in accordance with EC-i, Scheduling. Scheduling considerations will be different when working near perennial streams vs. ephemeral streams and are as follows. • When in-stream construction is conducted in a perennial stream, work should optimally be performed during the rainy season. This is because in the summer, any sediment-containing water that is discharged into the watercourse will cause a large change in both water clarity and water chemistry. During the rainy season, there is typically more and faster flowing water in the stream so discharges are diluted faster. However, should in-stream work be scheduled for summer, establishing an isolation area, or diverting the stream, will significantly decrease the amount of sediment stirred up by construction work. Construction / work near perennial streams should optimally be performed during the dry season (see ^ below). • When working in or near ephemeral streams, work should be performed during the dry season. By their very nature, ephemeral streams are usually dry in the summer, and therefore, in-stream construction activities will not cause significant water quality problems. However, when tying up the site at the end of the project, wash any fines (see Washing Fines) that accumulated in the channel back into the bed material, to decrease pollution from the first rainstorm of the season. • When working near ephemeral or perennial streams, erosion and sediment controls (see silt fences, straw bale barriers, etc.) should be implemented to keep sediment out of stream channel. Minimize Disturbance • Minimize disturbance through: selection of the narrowest crossing location; limiting the number of equipment trips across a stream during construction; and, minimizing the number and size of work areas (equipment staging areas and spoil storage areas). Place work areas at least 50 ft from stream channel. Field reconnaissance should be conducted during the planning stage to identify work areas. Use of Pre-Disturbed Areas m Locate project sites and work areas in areas disturbed by prior construction or other activity when possible. 2 of 10 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Streambank Stabilization EC-12 Selection of Project Site • Avoid steep and unstable banks, highly erodible or saturated soils, or highly fractured rock. • Select project site that minimizes disturbance to aquatic species or habitat. Equipment Selection • Select equipment that reduces the amount of pressure exerted on the ground surface, and therefore, reduces erosion potential and/or use overhead or aerial access for transporting equipment across drainage channels. Use equipment that exerts ground pressures of less than 5 or 6 lb/in2, where possible. Low ground pressure equipment includes: wide or high flotation tires (34 to 72 in. wide); dual tires; bogie axle systems; tracked machines; lightweight equipment; and, central tire inflation systems. Streambank Stabilization Preservation of Existing Vegetation • Preserve existing vegetation in accordance with EC-2, Preservation of Existing Vegetation. In a Streambank environment, preservation of existing vegetation provides the following benefits. Water Quality Protection • Vegetated buffers on slopes trap sediment and promote groundwater recharge. The buffer width needed to maintain water quality ranges from 15 to 100 ft. On gradual slopes, most of the filtering occurs within the first 30 ft. Steeper slopes require a greater width of vegetative buffer to provide water quality benefits. Streambank Stabilization • The root system of riparian vegetation stabilizes streambanks by increasing tensile strength in the soil. The presence of vegetation modifies the moisture condition of slopes (infiltration, evapo transpiration, interception) and increases bank stability. Riparian Habitat • Buffers of diverse riparian vegetation provide food and shelter for riparian and aquatic organisms. Minimizing impacts to fisheries habitat is a major concern when working near streams and rivers. Riparian vegetation provides shade, shelter, organic matter (leaf detritus and large woody debris), and other nutrients that are necessary for fish and other aquatic organisms. Buffer widths for habitat concerns are typically wider than those recommended for water quality concerns (100 to 1500 ft). • When working near watercourses, it is important to understand the work site's placement in the watershed. Riparian vegetation in headwater streams has a greater impact on overall water quality than vegetation in downstream reaches. Preserving existing vegetation upstream is necessary to maintain water quality, minimize bank failure, and maximize riparian habitat, downstream of the work site. Limitations • Local county and municipal ordinances regarding width, extent and type of vegetative buffer required may exceed the specifications provided here; these ordinances should be investigated prior to construction. January 2003 California Stormwater BMP Handbook 3 of 10 Construction www.cabmphandbooks.com EC-12 Streambank Stabilization Streambank Stabilization Specific Installation • As a general rule, the width of a buffer strip between a road and the stream is recommended to be 50 ft plus four times the percent slope of the land, measured between the road and the top of stream bank. Hydraulic Mulch • Apply hydraulic mulch on disturbed streambanks above mean high water level in accordance with EC-3, Hydraulic Mulch to provide temporary soil stabilization. Limitations • Do not place hydraulic mulch or tackifiers below the mean high water level, as these materials could wash into the channel and impact water quality or possibly cause eutrophication (eutrophication is an algal bloom caused by excessively high nutrient levels in the water). Hydroseeding • Hydroseed disturbed streambanks in accordance with EC-4, Hydroseeding. Limitations m Do not place tackifiers or fertilizers below the mean high water level, as these materials could wash into the channel and impact water quality or possibly cause eutrophication. Soil Binders • Apply soil binders to disturbed streambanks in accordance with EC-5, Soil Binders. Limitations • Do not place soil binders below the mean high water level. Soil binder must be environmentally benign and non-toxic to aquatic organisms. Straw Mulch • Apply straw mulch to disturbed streambanks in accordance with EC-6, Straw Mulch. Limitations • Do not place straw mulch below the mean high water level, as this material could wash into the channel and impact water quality or possibly cause eutrophication. Geotextiles and Mats • Install geotextiles and mats as described in EC-y, Geotextiles and Mats, to stabilize disturbed channels and streambanks. Not all applications should be in the channel, for example, certain geotextile netting may snag fish gills and are not appropriate in fish bearing streams. Geotextile fabrics that are not biodegradable are not appropriate for in stream use. Additionally, geotextile fabric or blankets placed in channels must be adequate to sustain anticipated hydraulic forces. Earth Dikes, Drainage Swales, and Lined Ditches • Convey, intercept, or divert runoff from disturbed streambanks using EC-9, Earth Dikes and Drainage Swales. 4 of 10 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Streambank Stabilization EC-12 Limitations • Do not place earth dikes in watercourses, as these structures are only suited for intercepting sheet flow, and should not be used to intercept concentrated flow. • Appropriately sized velocity dissipation devices (EC-io) must be placed at outlets to minimize erosion and scour. Velocity Dissipation Devices • Place velocity dissipation devices at outlets of pipes, drains, culverts, slope drains, diversion ditches, swales, conduits or channels in accordance with EC-io, Velocity Dissipation Devices. Slope Drains m Use slope drains to intercept and direct surface runoff or groundwater into a stabilized watercourse, trapping device or stabilized area in accordance with EC-n, Slope Drains. Limitations • Appropriately sized outlet protection and velocity dissipation devices (EC-io) must be placed at outlets to minimize erosion and scour. Streambank Sediment Control Silt Fences • Install silt fences in accordance with SE-i, Silt Fence, to control sediment. Silt fences should only be installed where sediment laden water can pond, thus allowing the sediment to settle out. Fiber Rolls • Install fiber rolls in accordance with SE-5, Fiber Rolls, along contour of slopes above the high water level to intercept runoff, reduce flow velocity, release the runoff as sheet flow and provide removal of sediment from the runoff. In a stream environment, fiber rolls should be used in conjunction with other sediment control methods such as SE-i, Silt Fence or SE-g Straw Bale Barrier. Install silt fence, straw bale barrier, or other erosion control method along toe of slope above the high water level. Gravel Bag Berrn • A gravel bag berm or barrier can be utilized to intercept and slow the flow of sediment laden sheet flow runoff in accordance with SE-6, Gravel Bag Berm. In a stream environment gravel bag barriers can allow sediment to settle from runoff before water leaves the construction site and can be used to isolate the work area from the live stream. Limitations • Gravel bag barriers are not recommended as a perimeter sediment control practice around streams. Straw Bale Barrier • Install straw bale barriers in accordance with SE-9, Straw Bale Barrier, to control sediment. Straw bale barriers should only be installed where sediment laden water can pond, thus allowing the sediment to settle out. Install a silt fence in accordance with SE-i, Silt Fence, January 2003 California Stormwater BMP Handbook 5 of 10 Construction www.cabmphandbooks.com EC- 12 Stream bank Stabilization on down slope side of straw bale barrier closest to stream channel to provide added sediment control. Rock Filter Description and Purpose Rock filters are temporary erosion control barriers composed of rock that is anchored in place. Rock filters detain the sediment laden runoff, retain the sediment, and release the water as sheet flow at a reduced velocity. Typical rock filter installations are illustrated at the end of this BMP. Applications m Near the toe of slopes that may be subject to flow and rill erosion. Limitations • Inappropriate for contributing drainage areas greater than 5 acres. • Requires sufficient space for ponded water. • Ineffective for diverting runoff because filters allow water to slowly seep through. • Rock filter berms are difficult to remove when construction is complete. • Unsuitable in developed areas or locations where aesthetics is a concern. Specifications • Rock: open graded rock, 0.75 to 5 in. for concentrated flow applications. • Woven wire sheathing: i in. diameter, hexagonal mesh, galvanized 2Ogauge (used with rock filters in areas of concentrated flow). • In construction traffic areas, maximum rock berm heights should be 12 in. Berms should be constructed every 300 ft on slopes less than 5%, every 200 ft on slopes between 5% and 10%, and every 100 ft on slopes greater than 10%. Maintenance • Inspect and verify that activity-based BMPs are in place prior to the commencement of associated activities. While activities associated with the BMP are under way, inspect weekly during the rainy season and at two-week intervals in the non-rainy season to verify continued BMP implementation. • Inspect BMPs subject to non-stormwater discharges daily while non-stormwater discharges occur. • Reshape berms as needed and replace lost or dislodged rock, and filter fabric. • Sediment that accumulates in the BMP must be periodically removed in order to maintain BMP effectiveness. Sediment should be removed when the sediment accumulation reaches one third of the barrier height. Sediment removed during maintenance may be incorporated into earthwork on the site or disposed at an appropriate location. 6 of 10 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Streambank Stabilization EC-12 K-rail Description and Purpose This is temporary sediment control that uses K-rails to form the sediment deposition area, or to isolate the near bank construction area. Install K-rails at toe of slope in accordance with procedures described in NS-5, Clear Water Diversion. Barriers are placed end to end in a pre-designed configuration and gravel filled bags are used at the toe of the barrier and at their abutting ends to seal and prevent movement of sediment beneath or through the barrier walls. Appropriate Applications m This technique is useful at the toe of embankments, cuts or fills slopes. Limitations • The K-rail method should not be used to dewater a project site, as the barrier is not watertight. Implementation m Refer to NS-5, Clear Water Diversion, for implementation requirements. Instream Construction Sediment Control There are three different options currently available for reducing turbidity while working in a stream or river. The stream can be isolated from the area in which work is occurring by means of a water barrier, the stream can be diverted around the work site through a pipe or temporary channel, or one can employ construction practices that minimize sediment suspension. Whatever technique is implemented, an important thing to remember is that dilution can sometimes be the solution. A probable "worst time" to release high TSS into a stream system might be when the stream is very low; summer low flow, for example. During these times, the flow may be low while the biological activity in the stream is very high. Conversely, the addition of high TSS or sediment during a big storm discharge might have a relatively low impact, because the stream is already turbid, and the stream energy is capable of transporting both suspended solids, and large quantities of bedload through the system. The optimum time to "pull" in-stream structures may be during the rising limb of a storm hydrograph. Techniques to minimize Total Suspended Solids (TSS) m Padding - Padding laid in the stream below the work site may trap some solids that are deposited in the stream during construction. After work is done, the padding is removed from the stream, and placed on the bank to assist in re-vegetation. • Clean, washed gravel - Using clean, washed gravel decreases solid suspension, as there are fewer small particles deposited in the stream. • Excavation using a large bucket - Each time a bucket of soil is placed in the stream, a portion is suspended. Approximately the same amount is suspended whether a small amount of soil is placed in the stream, or a large amount. Therefore, using a large excavator bucket instead of a small one, will reduce the total amount of soil that washes downstream. January 2003 California Stormwater BMP Handbook 7 of 10 Construction www.cabmphandbooks.com EC-12 Streambank Stabilization • Use of dozer for backfilling - Using a dozer for backfilling instead of a backhoe follows the same principles - the fewer times soil is deposited in the stream, the less soil will be suspended. • Partial dewatering with a pump - Partially dewatering a stream with a pump reduces the amount of water, and thus the amount of water that can suspend sediment. Washing! Fines Definition and Purpose m Washing fines is an "in-channel" sediment control method, which uses water, either from a water truck or hydrant, to wash stream fines that were brought to the surface of the channel bed during restoration, back into the interstitial spaces of the gravel and cobbles. • The purpose of this technique is to reduce or eliminate the discharge of sediment from the channel bottom during the first seasonal flow. Sediment should not be allowed into stream channels; however, occasionally in-channel restoration work will involve moving or otherwise disturbing fines (sand and silt sized particles) that are already in the stream, usually below bankfull discharge elevation. Subsequent re-watering of the channel can result in a plume of turbidity and sedimentation. • This technique washes the fines back into the channel bed. Bedload materials, including gravel cobbles, boulders and those fines, are naturally mobilized during higher storm flows. This technique is intended to delay the discharge until the fines would naturally be mobilized. Appropriate Applications m This technique should be used when construction work is required in channels. It is especially useful in intermittent or ephemeral streams in which work is performed "in the dry", and which subsequently become re-watered. Limitations m The stream must have sufficient gravel and cobble substrate composition. • The use of this technique requires consideration of time of year and timing of expected stream flows. • The optimum time for the use of this technique is in the fall, prior to winter flows. • Consultation with, and approval from the Department of Fish and Game and the Regional Water Quality Control Board may be required. Implementation m Apply sufficient water to wash fines, but not cause further erosion or runoff. • Apply water slowly and evenly to prevent runoff and erosion. • Consult with Department of Fish and Game and the Regional Water Quality Control Board for specific water quality requirements of applied water (e.g. chlorine). 8 of 10 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com o Streambank Stabilization EC-12 Inspection and Maintenance m None necessary Costs Cost may vary according to the combination of practices implemented. Inspection and Maintenance • Inspect and verify that activity-based BMPs are in place prior to the commencement of associated activities. While activities associated with the BMP are under way, inspect weekly during the rainy season and at two-week intervals in the non-rainy season to verify continued BMP implementation. • Inspect BMPs subject to non-stormwater discharges daily while non-stormwater discharges occur. • Inspect and repair equipment (for damaged hoses, fittings, and gaskets). References Manual of Standards of Erosion and Sediment Control Measures, Association of Bay Area Governments, May 1995. Proposed Guidance Specifying Management Measures for Sources of Nonpoint Pollution in Coastal Waters, Work Group Working Paper, USEPA, April 1992. Sedimentation and Erosion Control Practices, An Inventory of Current Practices (Draft), UESPA, 1990. Stormwater Quality Handbooks Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Stormwater Management for Construction Activities, Developing Pollution Prevention Plans and Best Management Practices, EPA 832-^92005; USEPA, April 1992. Water Quality Management Plan for the Lake Tahoe Region, Volume II, Handbook of Management Practices, Tahoe Regional Planning Agency, November 1988. January 2003 California Stormwater BMP Handbook 9 of 10 Construction www.cabmphandbooks.com EC-12 Streambank Stabilization 1 in. to 5 in Rock berm 8 in. for non traffic areas (Max 2 in. for traffic areas (Max) SECT ON 1 in. to 5 in Rock berm PLAN "YPICAL ROCK FILTER NOT TO SCALE OJ CO "O CO Dcu O O O 10 of 10 California Stormwater BMP Handbook Construction www.cabmphandbooks.com January 2003 Polyacrylamide EC-13 Description and Purpose Polyacrylamide (PAM) is a chemical that can be applied to disturbed oils at construction sites to reduce erosion and improve settling of suspended sediment. PAM increases the soil's available pore volume, thus increasing infiltration and reducing the quantity of stormwater runoff that can cause erosion. Suspended sediments from PAM treated soils exhibit increased flocculation over untreated soils. The increased flocculation aids in their deposition, thus reducing stormwater runoff turbidity and improving water quality. Suitable Applications PAM is suitable for use on disturbed soil areas that discharge to a sediment trap or sediment basin. PAM is typically used in conjunction with other BMPs to increase their performance. PAM can be applied to the following areas: • Rough graded soils that will be inactive for a period of time. • Final graded soils before application of final stabilization (e.g., paving, planting, mulching). • Temporary haul roads prior to placement of crushed rock surfacing. • Compacted soil road base. • Construction staging, materials storage, and layout areas. Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: if Primary Objective / Secondary Objective Targeted Constituents Sediment Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives None CASQA California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 6 EC-13 Polyacrylamide • Soil stockpiles. • Areas that will be mulched. Limitations • There is limited experience in California with use of PAM for erosion and sediment control. • PAM shall not be directly applied to water or allowed to enter a water body. • Do not use PAM on a slope that flows into a water body without passing through a sediment trap or sediment basin. • PAM will work when applied to saturated soil but is not as effective as applications to dry or damp soil. • Some PAMs are more toxic and carcinogenic than others. Only the most environmentally safe PAM products should be used. • The specific PAM copolymer formulation must be anionic. Cationic PAM shall not be used in any application because of known aquatic toxicity problems. Only the highest drinking water grade PAM, certified for compliance with ANSI/NSF Standard 60 for drinking water treatment, will be used for soil applications. • PAM designated for erosion and sediment control should be "water soluble" or "linear" or "non-cross linked". • A sampling and analysis plan must be incorporated into the SWPPP as PAM may be considered to be a source of non-visible pollutants. Implementation General PAM shall be used in accordance with the following general guidance: • Pam shall be used in conjunction with other BMPs and not in place of other BMPs, including both erosion controls and sediment controls. • Stormwater runoff from PAM treated soils should pass through a sediment control BMP prior to discharging to surface waters. When the total drainage area is greater than or equal to 5 acres, PAM treated areas shall drain to a sediment basin. Areas less than 5 acres shall drain to sediment control BMPs, such as a sediment trap, or a minimum of 3 check dams per acre. The total number of check dams used shall be maximized to achieve the greatest amount of settlement of sediment prior to discharging from the site. Each check dam shall be spaced evenly in the drainage channel. Through which stormwater flows are discharged off site. • Do not add PAM to water discharging from site. 2 of 6 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Polyacrylamide EC-13 "***"' • On PAM treated sites, the use of silt fence and fiber rolls shall be maximized to limit the discharges of sediment to sediment traps and sediment basins. • All areas not being actively worked one should be covered and protected from rainfall. PAM should not be the only cover BMP used. • PAM can be applied to wet soil, but dry soil is preferred due to less sediment loss. • Keep the granular PAM supply out of the sun. Granular PAM loses its effectiveness in three months after exposure to sunlight and air. • Proper application and re-application plans are necessary to ensure total effectiveness of PAM usage. • PAM, combined with water, is very slippery and can be a safety hazard. Care must be taken to prevent spills of PAM powder onto paved surfaces. During an application of PAM, prevent over spray from reaching pavement, as pavement will become slippery. If PAM powder gets on skin or clothing, wipe it off with a rough towel rather than washing with water this only makes cleanup messier and longer. • Recent high interest in PAM has resulted in some entrepreneurial exploitation of the term "polymer". All PAMs are polymer, but not all polymers are PAM, and not all PAM products comply with ANSI/NSF Standard 60. PAM use shall be reviewed and approved by the local permitting authority. '««»«*• • The PAM anionic charge density may vary from 2-30%; a value of 18% is typical. Studies conducted by the United States Department of Agriculture (USDA)/ Agricultural Research Service (ARS) demonstrated that soil stabilization was optimized by using very high molecular weight (12-15 mg/mole), highly anionic (>2O% hydrolosis) PAM. • PAM tackifiers are available and being used in place of guar and alpha plantago. Typically, PAM tackifiers should be used at a rate of no more than 0.5-1 Ib per 1,000 gallons of water in hydro mulch machine. Some tackifier product instructions say to use at a rate of 3-5 Ibs per acre, which can be too much. In addition, pump problems can occur at higher rates due to increased viscosity. Preferred Application Method PAM may be applied in dissolved form with water, or it may be applied in dry, granular, or powered form. The preferred application method is the dissolved form. PAM is to be applied at a maximum rate of ¥2 pound PAM per 1000 gallons water per l acre of bare soil. Table l and Figure l can be used to determine the PAM and water application rate for a disturbed soil area. Higher concentrations of PAM do not provide any additional effectiveness. January 2003 California Stormwater BMP Handbook 3 of 6 Construction www.cabmphandbooks.com Polyacrylamide EC-13 • Pre-fill the water truck about 1/8 full with water. The water does not have to be potable, but it must have relatively low turbidity - in the range of 20 NTU or less. • Add the dissolved PAM and water mixture to the truck. • Fill the water truck to specified volume for the amount of PAM to be applied. • Spray the PAM/water mixture onto dry soil until the soil surface is uniformly and completely wetted. Alternate Application Method PAM may also be applied as a powder at the rate of 5 Ibs per acre. This must be applied on a day that is dry. For areas less than 5-10 acres, a hand held "organ grinder" fertilizer spreader set to the smallest setting will work. Tractor mounted spreaders will work for larger areas. Costs • PAM: $1.30 - $5-5O/lb (material cost only). Inspection and Maintenance • Inspect BMPs prior to forecast rain, daily during extended rain events, after rain events, weekly during the rainy season, and at two-week intervals during the non-rainy season. • Areas where erosion is evident should be repaired and BMPs re-applied as soon as possible. Care should be exercised to minimize the damage to protected areas while making repairs, as any area damaged will require re-application of BMPs. • PAM must be reapplied on actively worked areas after a 48-hour period if PAM is to remain effective. • Reappiication is not required unless PAM treated soil is disturbed or unless turbidity levels show the need for an additional application. • If PAM treated soil is left undisturbed a reapplication may be necessary after two months. • More PAM applications may be required for steep slopes, silty and clayey soils (USDA Classification Type "C" and "D" soils), long grades, and high precipitation areas. • When PAM is applied first to bare soil and then covered with straw, a reapplication may not be necessary for several months. • Discharges from PAM treated areas must be monitored for non-visible pollutants. References Entry, J.A., and R.E. Sojka. Polyacrylamide Application to Soil Reduces the Movement of Microorganisms in Water. In 1999 Proceedings of the International Irrigation Show. Irrigation Associations, Orlando, FL, November, 1999. National Management Measures to Control Nonpoint Source Pollution from Urban Areas, United States Environmental Protection Agency, 2002. January 2003 California Stormwater BMP Handbook 5 of 6 Construction www.cabmphandbooks.com Silt Fence -1 Objectives Description and Purpose A silt fence is made of a filter fabric that has been entrenched, attached to supporting poles, and sometimes backed by a plastic or wire mesh for support. The silt fence detains sediment-laden water, promoting sedimentation behind the fence. Suitable Applications Silt fences are suitable for perimeter control, placed below areas where sheet flows discharge from the site. They should also be used as interior controls below disturbed areas where runoff may occur in the form of sheet and rill erosion. Silt fences are generally ineffective in locations where the flow is concentrated and are only applicable for sheet or overland flows. Silt fences are most effective when used in combination with erosion controls. Suitable applications include: • Along the perimeter of a project. • Below the toe or down slope of exposed and erodible slopes. • Along streams and channels. • Around temporary spoil areas and stockpiles. • Below other small cleared areas. Limitations • Do not use in streams, channels, drain inlets, or anywhere flow is concentrated. EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control ^ Legend: •/ Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives SE-5 Fiber Rolls SE-6 Gravel Bag Berm SE-8 Sandbag Barrier SE-9 Straw Bale Barrier ASQA California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 8 Silt Fence SE-1 • Provide sufficient room for runoff to pond behind the fence and to allow sediment removal equipment to pass between the silt fence and toes of slopes or other obstructions. About 1200 ft2 of ponding area should be provided for every acre draining to the fence. • Turn the ends of the filter fence uphill to prevent stormwater from flowing around the fence. • Leave an undisturbed or stabilized area immediately down slope from the fence where feasible. • Silt fences should remain in place until the disturbed area is permanently stabilized. Design and Layout Selection of a filter fabric is based on soil conditions at the construction site (which affect the equivalent opening size (EOS) fabric specification) and characteristics of the support fence (which affect the choice of tensile strength). The designer should specify a filter fabric that retains the soil found on the construction site yet that it has openings large enough to permit drainage and prevent clogging. The following criteria is recommended for selection of the equivalent opening size: 1. If 50 percent or less of the soil, by weight, will pass the U.S. Standard Sieve No. 200, select the EOS to retain 85 % of the soil. The EOS should not be finer than EOS 70. 2. For all other soil types, the EOS should be no larger than the openings in the U.S. Standard Sieve No. 70 except where direct discharge to a stream, lake, or wetland will occur, then the EOS should be no larger than Standard Sieve No. 100. To reduce the chance of clogging, it is preferable to specify a fabric with openings as large as allowed by the criteria. No fabric should be specified with an EOS smaller than U.S. Standard Sieve No. 100. If 85% or more of a soil, by weight, passes through the openings in a No. 200 sieve, filter fabric should not be used. Most of the particles in such a soil would not be retained if the EOS was too large and they would clog the fabric quickly if the EOS were small enough to capture the soil. The fence should be supported by a plastic or wire mesh if the fabric selected does not have sufficient strength and bursting strength characteristics for the planned application (as recommended by the fabric manufacturer). Filter fabric material should contain ultraviolet inhibitors and stabilizers to provide a minimum of six months of expected usable construction life at a temperature range of o °F to 120 °F. • Layout in accordance with attached figures. • For slopes steeper than 2:1 (H:V) and that contain a high number of rocks or large dirt clods that tend to dislodge, it may be necessary to install additional protection immediately adjacent to the bottom of the slope, prior to installing silt fence. Additional protection may be a chain link fence or a cable fence. • For slopes adjacent to sensitive receiving waters or Environmentally Sensitive Areas (ESAs), silt fence should be used in conjunction with erosion control BMPs. January 2003 California Stormwater BMP Handbook 3 of 8 Construction www.cabmphandbooks.com Silt Fence SE-1 • Construct the length of each reach so that the change in base elevation along the reach does not exceed 1/3 the height of the barrier; in no case should the reach exceed 500 ft. Costs • Average annual cost for installation and maintenance (assumes 6 month useful life): $7 per lineal foot ($850 per drainage acre). Range of cost is $3.50 - $9.10 per lineal foot. Inspection and Maintenance • Inspect BMPs prior to forecast rain, daily during extended rain events, after rain events, weekly during the rainy season, and at two-week intervals during the non-rainy season. • Repair undercut silt fences. • Repair or replace split, torn, slumping, or weathered fabric. The lifespan of silt fence fabric is generally 5 to 8 months. • Silt fences that are damaged and become unsuitable for the intended purpose should be removed from the site of work, disposed of, and replaced with new silt fence barriers. • Sediment that accumulates in the BMP must be periodically removed in order to maintain BMP effectiveness. Sediment should be removed when the sediment accumulation reaches one-third of the barrier height. Sediment removed during maintenance may be incorporated into earthwork on the site or disposed at an appropriate location. • Silt fences should be left in place until the upstream area is permanently stabilized. Until then, the silt fence must be inspected and maintained. • Holes, depressions, or other ground disturbance caused by the removal of the silt fences should be backfilled and repaired. References Manual of Standards of Erosion and Sediment Control Measures, Association of Bay Area Governments, May 1995. National Management Measures to Control Nonpoint Source Pollution from Urban Areas, United States Environmental Protection Agency, 2002. Proposed Guidance Specifying Management Measures for Sources of Nonpoint Pollution in Coastal Waters, Work Group-Working Paper, USEPA, April 1992. Sedimentation and Erosion Control Practices, and Inventory of Current Practices (Draft), UESPA, 1990. Southeastern Wisconsin Regional Planning Commission (SWRPC). Costs of Urban Nonpoint Source Water Pollution Control Measures. Technical Report No. 31. Southeastern Wisconsin Regional Planning Commission, Waukesha, Wl. 1991 Stormwater Quality Handbooks - Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. January 2003 California Stormwater BMP Handbook 5 of 8 Construction www.cabmphandbooks.com Silt Fence -1 oIo zgi—u LJ CO QJ c o-C O c*" o E "D t_C 3o o ,t± <u OJ O ~ .b E E a 3 a. {/i "o.o V)linirnum 4-* c -"-" sc O JIO11J CO Cc01a.o 4)aintenanc^ * tnc remaisediment—ojito t/1 Co uCDl/l C 'c 'o-5 January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 7 of 8 Sediment Basin SE-2 •'»»*»•«" Objectives Description and Purpose A sediment basin is a temporary basin formed by excavation or by constructing an embankment so that sediment-laden runoff is temporarily detained under quiescent conditions, allowing sediment to settle out before the runoff is discharged. Suitable Applications Sediment basins may be suitable for use on larger projects with sufficient space for constructing the basin. Sediment basins should be considered for use: • Where sediment-laden water may enter the drainage system or watercourses • On construction projects with disturbed areas during the rainy season • At the outlet of disturbed watersheds between 5 acres and 75 acres • At the outlet of large disturbed watersheds, as necessary • Where post construction detention basins are required • In association with dikes, temporary channels, and pipes used to convey runoff from disturbed areas Limitations Sediment basins must be installed only within the property limits and where failure of the structure will not result in loss of life, damage to homes or buildings, or interruption of use or service of EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: if Primary Objective J Secondary Objective Targeted Constituents Sediment 1 Nutrients Trash i Metals Bacteria Oil and Grease Organics Potential Alternatives SE-3 Sediment Trap (for smaller areas) C AS QA lifornla Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 12 Sediment Basin SE-2 temporary seeding, mulching, diversion dikes, etc., to reduce the amount of sediment flowing into the basin. Planning To improve the effectiveness of the basin, it should be located to intercept runoff from the largest possible amount of disturbed area. The best locations are generally low areas. Drainage into the basin can be improved by the use of earth dikes and drainage swales (see BMP EC-9). The basin must not be located in a stream but it should be located to trap sediment-laden runoff before it enters the stream. The basin should not be located where its failure would result in the loss of life or interruption of the use or service of public utilities or roads. • Construct before clearing and grading work begins when feasible. • Do not locate in a stream. • Basin sites should be located where failure of the structure will not cause loss of life, damage to homes or buildings, or interruption of use or service of public roads or utilities. • Large basins are subject to state and local dam safety requirements. • Limit the contributing area to the sediment basin to only the runoff from the disturbed soil areas. Use temporary concentrated flow conveyance controls to divert runoff from undisturbed areas away from the sediment basin. • The basin should be located: (i) by excavating a suitable area or where a low embankment can be constructed across a swale, (2) where post-construction (permanent) detention basins will be constructed, and (3) where the basins can be maintained on a year-round basis to provide access for maintenance, including sediment removal and sediment stockpiling in a protected area, and to maintain the basin to provide the required capacity. Design Sediment basins must be designed in accordance with Section A of the State of California NPDES General Permit for Stormwater Discharges Associated with Construction Activities (General Permit) where sediment basins are the only control measure proposed for the site. If there is insufficient area to construct a sediment basin in accordance with the General Permit requirements, then the alternate design standards specified herein may be used. Sediment basins designed per the General Permit shall be designed as follows: Option i: Pursuant to local ordinance for sediment basin design and maintenance, provided that the design efficiency is as protective or more protective of water quality than Option 3. OR Option 2: Sediment basin(s), as measured from the bottom of the basin to the principal outlet, shall have at least a capacity equivalent to 3,600 cubic feet (133 yd3) of storage per acre draining into the sediment basin. The length of the basin shall be more than twice the width of the basin. The January 2003 California Stormwater BMP Handbook 3 of 12 Construction www.cabmphandbooks.com Sediment Basin SE-2 Other design considerations are: • The volume of the settling zone should be sized to capture runoff from a 2-year storm or other appropriate design storms specified by the local agency. A detention time of 24 to 40 hours should allow 70 to 80 % of sediment to settle. • The basin volume consists of two zones: A sediment storage zone at least i ft deep. A settling zone at least 2 ft deep. • The length to settling depth ratio (L/SD) should be less than 200. • Sediment basins are best used in conjunction with erosion controls. Sediment basins that will be used as the only means of treatment, without upstream erosion and sediment controls, must be designed according to the four options required by the General Permit (see Options 1-4 above). Sediment basins that are used in conjunction with upstream erosion and sediment controls should be designed to have a capacity equivalent to 67 yds of sediment storage per acre of contributory area. • The length of the basin should be more than twice the width of the basin; the length should be determined by measuring the distance between the inlet and the outlet. • The depth must be no less than 3 ft. • Basins with an impounding levee greater than 4.5 ft tall, measured from the lowest point to the impounding area to the highest point of the levee, and basins capable of impounding more than 35,000 fts, should be designed by a Registered Civil Engineer. The design should include maintenance requirements, including sediment and vegetation removal, to ensure continuous function of the basin outlet and bypass structures. • Basins should be designed to drain within 72 hours following storm events. If a basin fails to drain within 72 hours, it must be pumped dry. • Sediment basins, regardless of size and storage volume, should include features to accommodate overflow or bypass flows that exceed the design storm event. Include an emergency spillway to accommodate flows not carried by the principal spillway. The spillway should consist of an open channel (earthen or vegetated) over undisturbed material (not fill) or constructed of a non-erodible riprap. The spillway control section, which is a level portion of the spillway channel at the highest elevation in the channel, should be a minimum of 20 ft in length. • Rock or vegetation should be used to protect the basin inlet and slopes against erosion. • A forebay, constructed upstream of the basin may be provided to remove debris and larger particles. January 2003 California Stormwater BMP Handbook 5 of 12 Construction www.cabmphandbooks.com Sediment Basin SE-2 g = gravity (32.2 ft/s2) H = elevation when the basin is full (ft) Ho = final elevation when basin is empty (ft) With a drawdown time of 40 hours, the equation becomes: (\.15x\Q~*) A(H-Hof (Eq.3) a =C Flow Control Using Multiple Orifices (see Figure2): t o *-'•' V-^ Si "max ~ "-centroid of orifices \) C^JQ A] With terms as described above except: at - total area of orifices hmax = maximum height from lowest orifice to the maximum water surface (ft) hcentroid of orifices = height from the lowest orifice to the centroid of the orifice configuration (ft) Allocate the orifices evenly on two rows; separate the holes by 3x hole diameter vertically, and by 120 degrees horizontally (refer to Figure 2). Because basins are not maintained for infiltration, water loss by infiltration should be disregarded when designing the hydraulic capacity of the outlet structure. Care must be taken in the selection of "C"; 0.60 is most often recommended and used. However, based on actual tests, GKY (1989), "Outlet Hydraulics of Extended Detention Facilities for Northern Virginia Planning District Commission", recommends the following: C = 0.66 for thin materials; where the thickness is equal to or less than the orifice diameter, or C = 0.80 when the material is thicker than the orifice diameter Installation • Securely anchor and install an anti-seep collar on the outlet pipe/riser and provide an emergency spillway for passing major floods (see local flood control agency). • Areas under embankments must be cleared and stripped of vegetation. • Chain link fencing should be provided around each sediment basin to prevent unauthorized entry to the basin or if safety is a concern. January 2003 California Stormwater BMP Handbook 7 of 12 Construction www.cabmphandbooks.com Sediment Basin SE-2 Manual of Standards of Erosion and Sediment Control Measures, Association of Bay Area Governments, May 1995. McLean, J., 2000. Mosquitoes in Constructed Wetlands: A Management Bugaboo? In T.R. Schueler and H.K. Holland [eds.], The Practice of Watershed Protection, pp. 29-33. Center for Watershed Protection, Ellicott City, MD, 2000. Metzger, M.E., D. F. Messer, C. L. Beitia, C. M. Myers, and V. L. Kramer. The dark site of stormwater runoff management: disease vectors associated with structural BMPs, 2002. National Management Measures to Control Nonpoint Source Pollution from Urban Areas, United States Environmental Protection Agency, 2002. Proposed Guidance Specifying Management Measures for Sources of Nonpoint Pollution in Coastal Water, Work Group-Working Paper, USEPA, April 1992. Stormwater Quality Handbooks - Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Stormwater Management of the Puget Sound Basin, Technical Manual, Publication #91-75, Washington State Department of Ecology, February 1992. U.S. Environmental Protection Agency (USEPA). Guidance Specifying Management Measures for Nonpoint Pollution in Coastal Waters. EPA 840-6-9-002. U.S. Environmental Protection Agency, Office of Water, Washington, DC, 1993 Water Quality Management Plan for the Lake Tahoe Region, Volume II Handbook of Management Practices, Tahoe Regional Planning Agency, November 1988. January 2003 California Stormwater BMP Handbook 9 of 12 Construction www.cabmphandbooks.com Sediment Basin SE-2 Stabilized inlet ^ / Embankment Side slopes 3:1 (H:V) Max Outlet protection TOP VIEW Emergency spillway Inflow Settling depth- 24" Min depth Sediment storage depth - 12 Min Riser w/ hood & trash rack .V Emergency spillway 12" Stabilized Outlet See EC-10 Riser encased in gravel —' jacket. Upper two-thirds perforated. Anti-seep collars -Anti —floatation block SIDE VIEW EIGURE 2: TYPICAL TEMPORARY SEDIMENT BASIN MULTIPLE ORIEICE DESIGN NOT TO SCALE January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 11 of 12 Sediment Trap SE-3I^L. taJ Description and Purpose A sediment trap is a containment area where sediment-laden runoff is temporarily detained under quiescent conditions, allowing sediment to settle out or before the runoff is discharged. Sediment traps are formed by excavating or constructing an earthen embankment across a waterway or low drainage area. Suitable Applications Sediment traps should be considered for use: • At the perimeter of the site at locations where sediment- laden runoff is discharged offsite. • At multiple locations within the project site where sediment control is needed. • Around or upslope from storm drain inlet protection measures. • Sediment traps may be used on construction projects where the drainage area is less than 5 acres. Traps would be placed where sediment-laden stormwater may enter a storm drain or watercourse. SE-2, Sediment Basins, must be used for drainage areas greater than 5 acres. • As a supplemental control, sediment traps provide additional protection for a water body or for reducing sediment before it enters a drainage system. Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control S Legend: J Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients Trash < Metals Bacteria Oil and Grease Organics Potential Alternatives SE-2 Sediment Basin (for larger areas) CASQA ilfOrnla Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com lof 6 Sediment Trap SE-3 • Locate sediment traps as near as practical to areas producing the sediment. • Trap should be situated according to the following criteria: (i) by excavating a suitable area or where a low embankment can be constructed across a swale, (2) where failure would not cause loss of life or property damage, and (3) to provide access for maintenance, including sediment removal and sediment stockpiling in a protected area. • Trap should be sized to accommodate a settling zone and sediment storage zone with recommended minimum volumes of 67 yd3/acre and 33 yd3/acre of contributing drainage area, respectively, based on 0.5 in. of runoff volume over a 24-hour period. In many cases, the size of an individual trap is limited by available space. Multiple traps or additional volume may be required to accommodate specific rainfall, soil, and site conditions. • Traps with an impounding levee greater than 4.5 ft tall, measured from the lowest point to the impounding area to the highest point of the levee, and traps capable of impounding more than 35,000 ft3, should be designed by a Registered Civil Engineer. The design should include maintenance requirements, including sediment and vegetation removal, to ensure continuous function of the trap outlet and bypass structures. • The outlet pipe or open spillway must be designed to convey anticipated peak flows. • Use rock or vegetation to protect the trap outlets against erosion. • Fencing should be provided to prevent unauthorized entry. Installation Sediment traps can be constructed by excavating a depression in the ground or creating an impoundment with a small embankment. Sediment traps should be installed outside the area being graded and should be built prior to the start of the grading activities or removal of vegetation. To minimize the area disturbed by them, sediment traps should be installed in natural depressions or in small swales or drainage ways. The following steps must be followed during installation: • The area under the embankment must be cleared, grubbed, and stripped of any vegetation and root mat. The pool area should be cleared. • The fill material for the embankment must be free of roots or other woody vegetation as well as oversized stones, rocks, organic material, or other objectionable material. The embankment may be compacted by traversing with equipment while it is being constructed. • All cut-and-fill slopes should be 3:1 or flatter. • When a riser is used, all pipe joints must be watertight. • When a riser is used, at least the top two-thirds of the riser should be perforated with 0.5 in. diameter holes spaced 8 in. vertically and 10 to 12 in. horizontally. See SE-2, Sediment Basin. • When an earth or stone outlet is used, the outlet crest elevation should be at least i ft below the top of the embankment. January 2003 California Stormwater BMP Handbook 3 of 6 Construction www.cabmphandbooks.com Sediment Trap SE-3 National Management Measures to Control Nonpoint Source Pollution from Urban Areas, United States Environmental Protection Agency, 2002. Proposed Guidance Specifying Management Measures for Sources of Nonpoint Pollution in Coastal Waters, Work Group-Working Paper, USEPA, April 1992. Stormwater Quality Handbooks - Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Stormwater Management Manual for The Puget Sound Basin, Washington State Department of Ecology, Public Review Draft, 1991. U.S. Environmental Protection Agency (USEPA). Guidance Specifying Management Measures for Nonpoint Pollution in Coastal Waters. EPA 840-6-9-002. U.S. Environmental Protection Agency, Office of Water, Washington, DC, 1993. Water Quality Management Plan for the Lake Tahoe Region, Volume II, Handbook of Management Practices, Tahoe Regional Planning Agency, November 1988. January 2003 California Stormwater BMP Handbook 5 of 6 Construction www.cabmphandbooks.com Check Dams SE-4 Objectives Description and Purpose A check dam is a small barrier constructed of rock, gravel bags, sandbags, fiber rolls, or reusable products, placed across a constructed swale or drainage ditch. Check dams reduce the effective slope of the channel, thereby reducing the velocity of flowing water, allowing sediment to settle and reducing erosion. Suitable Applications Check dams may be appropriate in the following situations: • To promote sedimentation behind the dam. • To prevent erosion by reducing the velocity of channel flow in small intermittent channels and temporary swales. • In small open channels that drain 10 acres or less. • In steep channels where stormwater runoff velocities exceed 5 ft/s. • During the establishment of grass linings in drainage ditches or channels. • In temporary ditches where the short length of service does not warrant establishment of erosion-resistant linings. Limitations • Not to be used in live streams or in channels with extended base flows. EC SE TC WE NS Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control .._. Waste Management and Materials Pollution Control Legend: v Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives SE-5 Fiber Rolls SE-6 Gravel Bag Berm SE-8 Sandbag Barrier ^California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 5 Check Dams SE-4 or swale to prevent washout. The rock used must be large enough to stay in place given the expected design flow through the channel. Log check dams are usually constructed of 4 to 6 in. diameter logs. The logs should be embedded into the soil at least 18 in. Logs can be bolted or wired to vertical support logs that have been driven or buried into the soil. Gravel bag and sandbag check dams are constructed by stacking bags across the ditch or swale, shaped as shown in the drawings at the end of this fact sheet. Manufactured products should be installed in accordance with the manufacturer's instructions. If grass is planted to stabilize the ditch or swale, the check dam should be removed when the grass has matured (unless the slope of the swales is greater than 4%). The following guidance should be followed for the design and layout of check dams: • Install the first check dam approximately 16 ft from the outfall device and at regular intervals based on slope gradient and soil type. • Check dams should be placed at a distance and height to allow small pools to form between each check dam. • Backwater from a downstream check dam should reach the toes of the upstream check dam. • A sediment trap provided immediately upstream of the check dam will help capture sediment. Due to the potential for this sediment to be resuspended in subsequent storms, the sediment trap must be cleaned following each storm event. • High flows (typically a 2-year storm or larger) should safely flow over the check dam without an increase in upstream flooding or damage to the check dam. • Where grass is used to line ditches, check dams should be removed when grass has matured sufficiently to protect the ditch or swale. » Gravel bags may be used as check dams with the following specifications: Materials Gravel bags used for check dams should conform to the requirements of SE-6, Gravel Bag Berms. Sandbags used for check dams should conform to SE-8, Sandbag Barrier. Fiber rolls used for check dams should conform to SE-5, Fiber Rolls. Straw bales used for check dams should conform to SE-9, Straw Bale Barrier. Installation • Rock should be placed individually by hand or by mechanical methods (no dumping of rock) to achieve complete ditch or swale coverage. • Tightly abut bags and stack according to detail shown in the figure at the end of this section. Gravel bags and sandbags should not be stacked any higher than 3 ft. • Fiber rolls and straw bales must be trenched in and firmly staked in place. January 2003 California Stormwater BMP Handbook 3 of 5 Construction www.cabmphandbooks.com Check Dams SE-4 1.5 ft mirr ELEVATION 8" to 12" diameter rock Flow TYPICAL ROCK CHECK DAM SECTION ROCK CHECK DAM NOT TO SCALE 1C) GRAVEL BAG CHECK DAM ELEVATION NOT TO SCALE January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 5 of 5 Fiber Rolls -5 Objectives Description and Purpose A fiber roll consists of straw, flax, or other similar materials bound into a tight tubular roll. When fiber rolls are placed at the toe and on the face of slopes, they intercept runoff, reduce its flow velocity, release the runoff as sheet flow, and provide removal of sediment from the runoff. By interrupting the length of a slope, fiber rolls can also reduce erosion. Suitable Applications Fiber rolls may be suitable: • Along the toe, top, face, and at grade breaks of exposed and erodible slopes to shorten slope length and spread runoff as sheet flow • At the end of a downward slope where it transitions to a steeper slope • Along the perimeter of a project • As check dams in unlined ditches • Down-slope of exposed soil areas • Around temporary stockpiles Limitations • Fiber rolls are not effective unless trenched EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: </ Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives SE-1 Silt Fence SE-6 Gravel Bag Berm SE-8 Sandbag Barrier SE-9 Straw Bale Barrier CASQA {California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 4 Fiber Rolls SE-5 • If fiber rolls are removed, collect and dispose of sediment accumulation, and fill and compact holes, trenches, depressions or any other ground disturbance to blend with adjacent ground. Costs Material costs for fiber rolls range from $20 - $30 per 25 ft roll. Inspection and Maintenance • Inspect BMPs prior to forecast rain, daily during extended rain events, after rain events, weekly during the rainy season, and at two-week intervals during the non-rainy season. • Repair or replace split, torn, unraveling, or slumping fiber rolls. • If the fiber roll is used as a sediment capture device, or as an erosion control device to maintain sheet flows, sediment that accumulates in the BMP must be periodically removed in order to maintain BMP effectiveness. Sediment should be removed when sediment accumulation reaches one-half the designated sediment storage depth, usually one-half the distance between the top of the fiber roll and the adjacent ground surface. Sediment removed during maintenance maybe incorporated into earthwork on the site of disposed at an appropriate location. • If fiber rolls are used for erosion control, such as in a mini check dam, sediment removal should not be required as long as the system continues to control the grade. Sediment control BMPs will likely be required in conjunction with this type of application. References Stormwater Quality Handbooks - Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. January 2003 California Stormwater BMP Handbook 3 of 4 Construction www.cabmphandbooks.com Gravel Bag Berm SE-6 Description and Purpose A gravel bag berm is a series of gravel-filled bags placed on a level contour to intercept sheet flows. Gravel bags pond sheet flow runoff, allowing sediment to settle out, and release runoff slowly as sheet flows, preventing erosion. Suitable Applications Gravel bag berms may be suitable: • As a linear sediment control measure: Below the toe of slopes and erodible slopes As sediment traps at culvert/pipe outlets Below other small cleared areas Along the perimeter of a site Down slope of exposed soil areas Around temporary stockpiles and spoil areas Parallel to a roadway to keep sediment off paved areas Along streams and channels • As linear erosion control measure: Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: if Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives SE-1 Silt Fence SE-5 Fiber Roll SE-8 Sandbag Barrier SE-9 Straw Bale Barrier CAS a A California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 4 Gravel Bag Berm SE-6 • For installation near the toe of the slope, consider moving the gravel bag barriers away from the slope toe to facilitate cleaning. To prevent flows behind the barrier, bags can be placed perpendicular to a berm to serve as cross barriers. • Drainage area should not exceed 5 acres. • In Non-Traffic Areas: Height = 18 in. maximum Top width = 24 in. minimum for three or more layer construction Top width = 12 in. minimum for one or two layer construction - Side slopes = 2:1 or flatter • In Construction Traffic Areas: Height = 12 in. maximum Top width = 24 in. minimum for three or more layer construction. Top width = 12 in. minimum for one or two layer construction. Side slopes = 2:1 or flatter. •'»*»*»' • Butt ends of bags tightly • On multiple row, or multiple layer construction, overlapp butt joints of adjacent row and row beneath. • Use a pyramid approach when stacking bags. Materials m Bag Material: Bags should be woven polypropylene, polyethylene or polyamide fabric or burlap, minimum unit weight of 4 ounces/yd2, Mullen burst strength exceeding 300 lb/in2 in conformance with the requirements in ASTM designation 03786, and ultraviolet stability exceeding 70% in conformance with the requirements in ASTM designation 04355. • Bag Size: Each gravel-filled bag should have a length of 18 in., width of 12 in., thickness of 3 in., and mass of approximately 33 Ibs. Bag dimensions are nominal, and may vary based on locally available materials. • Fill Material: Fill material should be 0.5 to i in. Class 2 aggregate base, clean and free from clay, organic matter, and other deleterious material, or other suitable open graded, non-cohesive, porous gravel. Costs Gravel filter: Expensive, since off-site materials, hand construction, and demolition/removal are usually required. Material costs for gravel bags are average of $2.50 per empty gravel bag. Gravel costs range from $20-$35 per yds. January 2003 California Stormwater BMP Handbook 3 of 4 Construction www.cabmphandbooks.com Street Sweeping and Vacuuming SE-7 Description and Purpose Street sweeping and vacuuming includes use of self-propelled and walk-behind equipment to remove sediment from streets and roadways, and to clean paved surfaces in preparation for final paving. Sweeping and vacuuming prevents sediment from the project site from entering storm drains or receiving waters. Suitable Applications Sweeping and vacuuming are suitable anywhere sediment is tracked from the project site onto public or private paved streets and roads, typically at points of egress. Sweeping and vacuuming are also applicable during preparation of paved surfaces for final paving. Limitations Sweeping and vacuuming may not be effective when sediment is wet or when tracked soil is caked (caked soil may need to be scraped loose). Implementation • Controlling the number of points where vehicles can leave the site will allow sweeping and vacuuming efforts to be focused, and perhaps save money. • Inspect potential sediment tracking locations daily. • Visible sediment tracking should be swept or vacuumed on a daily basis. Objectives j EC Erosion Control SE Sediment Control TC Tracking Control WE Wind Erosion Control Non-StormwaterNSManagement Control „_. Waste Management and Materials Pollution Control Legend: */ Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients Trash i Metals Bacteria Oil and Grease i Organics Potential Alternatives None ASQA California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 2 Sandbag Barrier SE-8 Description and Purpose A sandbag barrier is a series of sand-filled bags placed on a level contour to intercept sheet flows. Sandbag barriers pond sheet flow runoff, allowing sediment to settle out. Suitable Applications Sandbag barriers may be suitable: • As a linear sediment control measure: Below the toe of slopes and erodible slopes As sediment traps at culvert/pipe outlets Below other small cleared areas Along the perimeter of a site Down slope of exposed soil areas Around temporary stockpiles and spoil areas Parallel to a roadway to keep sediment off paved areas - Along streams and channels • As linear erosion control measure: - Along the face and at grade breaks of exposed and erodible slopes to shorten slope length and spread runoff as sheet flow Objectives EC Erosion Control SE Sediment Control TC Tracking Control WE Wind Erosion Control Non-Stormwater Management ControlNS „... Waste Management and Materials Pollution Control Legend: if Primary Objective -/ Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease Organics Potentia! Alternatives SE-1 Silt Fence SE-5 Fiber Rolls SE-6 Gravel Bag Berm SE-9 Straw Bale Barrier .CASQA California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 6 Sandbag Barrier SE-8 • Stack sandbags at least three bags high. • Butt ends of bags tightly. • Overlapp butt joints of row beneath with each successive row. • Use a pyramid approach when stacking bags. • In non-traffic areas Height = 18 in. maximum - Top width = 24 in. minimum for three or more layer construction Side slope = 2:1 or flatter • In construction traffic areas Height = 12 in. maximum Top width = 24 in. minimum for three or more layer construction. Side slopes = 2:1 or flatter. Materials m Sandbag Material: Sandbag should be woven polypropylene, polyethylene or polyamide fabric, minimum unit weight of 4 ounces/yd2, Mullen burst strength exceeding 300 lb/in2 in conformance with the requirements in ASTM designation 03786, and ultraviolet stability exceeding 70% in conformance with the requirements in ASTM designation 04355. Use of burlap may not acceptable in some jurisdictions. • Sandbag Size: Each sand-filled bag should have a length of 18 in., width of 12 in., thickness of 3 in., and mass of approximately 33 Ibs. Bag dimensions are nominal, and may vary based on locally available materials. • Fill Material: All sandbag fill material should be non-cohesive, Class i or Class 2 permeable material free from clay and deleterious material. Costs Sandbag barriers are more costly, but typically have a longer useful life than other barriers. Empty sandbags cost $0.25 - $0.75. Average cost of fill material is $8 per yd3. Pre-filled sandbags are more expensive at $1.50 - $2.00 per bag. Inspection and Maintenance • Inspect BMPs prior to forecast rain, daily during extended rain events, after rain events, weekly during the rainy season, and at two-week intervals during the non-rainy season. • Sandbags exposed to sunlight will need to be replaced every two to three months due to degradation of the bags. • Reshape or replace sandbags as needed. January 2003 California Stormwater BMP Handbook 3 of 6 Construction www.cabmphandbooks.com Sandbag Barrier SE-8 UJ5ce<CD CD Q .E OOlO u i 3? 9 - E O •- = JJ en _ «> 75 £ <u °oi-c c s^^III — c O U o -Q ; -s .g ;= ~ o o E = .« -0 O TJ o _ .« ° -^ '^ e£ §I- O " (/) January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 5 of 6 Straw Bale Barrier Objectives Description and Purpose A straw bale barrier is a series of straw bales placed on a level contour to intercept sheet flows. Straw bale barriers pond sheet- flow runoff, allowing sediment to settle out. Suitable Applications Straw bale barriers may be suitable: • As a linear sediment control measure: Below the toe of slopes and credible slopes As sediment traps at culvert/pipe outlets Below other small cleared areas Along the perimeter of a site Down slope of exposed soil areas Around temporary stockpiles and spoil areas Parallel to a roadway to keep sediment off paved areas - Along streams and channels • As linear erosion control measure: - Along the face and at grade breaks of exposed and erodible slopes to shorten slope length and spread runoff as sheet flow EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: </ Primary Objective •/ Secondary Objective Targeted Constituents Sediment ^ Nutrients Trash Metals Bacteria Oil and Grease Organics Potentiai Aiternatives SE-1 Silt Fence SE-5 Fiber Rolls SE-6 Gravel Bag Berm SE-8 Sandbag Barrier ilifornla Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 6 Straw Bale Barrier SE-9 • Turn the ends of the straw bale barrier up slope to prevent runoff from going around the barrier. • Allow sufficient space up slope from the barrier to allow ponding, and to provide room for sediment storage. • For installation near the toe of the slope, consider moving the barrier away from the slope toe to facilitate cleaning. To prevent flow behind the barrier, sand bags can be placed perpendicular to the barrier to serve as cross barriers. • Drainage area should not exceed i acre, or 0.25 acre per 100 ft of barrier. • Maximum flow path to the barrier should be limited to 100 ft. • Straw bale barriers should consist of two parallel rows. Butt ends of bales tightly Stagger butt joints between front and back row. Each row of bales must be trenched in and firmly staked • Straw bale barriers are limited in height to one bale laid on its side. • Anchor bales with either two wood stakes or four bars driven through the bale and into the soil. Drive the first stake towards the butt joint with the adjacent bale to force the bales together. • See attached figure for installation details. Materials • Straw Bale Size: Each straw bale should be a minimum of 14 in. wide, 18 in. in height, 36 in. in length and should have a minimum mass of 50 Ibs. The straw bale should be composed entirely of vegetative matter, except for the binding material. • Bale Bindings: Bales should be bound by steel wire, nylon or polypropylene string placed horizontally. Jute and cotton binding should not be used. Baling wire should be a minimum diameter of 14 gauge. Nylon or polypropylene string should be approximately 12 gauge in diameter with a breaking strength of 80 Ibs force. • Stakes: Wood stakes should be commercial quality lumber of the size and shape shown on the plans. Each stake should be free from decay, splits or cracks longer than the thickness of the stake, or other defects that would weaken the stakes and cause the stakes to be structurally unsuitable. Steel bar reinforcement should be equal to a #4 designation or greater. End protection should be provided for any exposed bar reinforcement. Costs Straw bales cost $5 - $7 each. Adequate labor should be budgeted for installation and maintenance. January 2003 California Stormwater BMP Handbook 3 of 6 Construction www.cabmphandbooks.com Straw Bale Barrier SE-9 0 .coas .coc 0 -C "c *£ - j r-' X oc (0 •a ij « £ -^ g 1 0ff 1 "6s V u oc ~ .¥ .0 1 b1 ., c .2i ~3 "O> su_ it iH o Xs X0E3 c 3 -9- w " 5!? E = b •j i*i o | c o oMC0) ^<D| t/) •*' Vc.s.o X ^£CT> V)Q) "5.£» $O soa. iri «4J."9 0)cao»o n 'o cV •DVn 1 a. I— to 0o 1 0) o T5^1 <u1 -ooo¥ •p 0>co 1o r^ to 0^s A o +* c £ "D&0 o *-VC w" OT ID'S January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 5 of 6 Storm Drain Inlet Protection SE-10 Objectives Description and Purpose Storm drain inlet protection consists of a sediment filter or an impounding area around or upstream of a storm drain, drop inlet, or curb inlet. Storm drain inlet protection measures temporarily pond runoff before it enters the storm drain, allowing sediment to settle. Some filter configurations also remove sediment by filtering, but usually the ponding action results in the greatest sediment reduction. Suitable Applications Every storm drain inlet receiving sediment-laden runoff should be protected. Limitations • Drainage area should not exceed i acre. • Straw bales, while potentially effective, have not produced in practice satisfactory results, primarily due to improper installation. • Requires an adequate area for water to pond without encroaching into portions of the roadway subject to traffic. • Inlet protection usually requires other methods of temporary protection to prevent sediment-laden stormwater and non-stormwater discharges from entering the storm drain system. • Sediment removal may be difficult in high flow conditions or if runoff is heavily sediment laden. If high flow conditions are EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: if Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients Trash i Metals Bacteria Oil and Grease Organics Potential Alternatives SE-1 Silt Fence SE-5 Fiber Rolls SE-6 Gravel Bag Berm SE-8 Sandbag Barrier SE-9 Straw Bale Barrier California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 9 Storm Drain Inlet Protection SE-10 inlet protection device a short distance upstream of the actual inlet can provide more efficient sediment control, limit ponding to desired areas, and prevent or control diversions. • Four types of inlet protection are presented below. However, it is recognized that other effective methods and proprietary devices exist and may be selected. Filter Fabric Fence: Appropriate for drainage basins with less than a 5% slope, sheet flows, and flows under 0.5 cfs. Excavated Drop Inlet Sediment Trap: An excavated area around the inlet to trap sediment (SE-3). Gravel bag barrier: Used to create a small sediment trap upstream of inlets on sloped, paved streets. Appropriate for sheet flow or when concentrated flow may exceed 0.5 cfs, and where overtopping is required to prevent flooding. Block and Gravel Filter: Appropriate for flows greater than 0.5 cfs. • Select the appropriate type of inlet protection and design as referred to or as described in this fact sheet. • Provide area around the inlet for water to pond without flooding structures and property. • Grates and spaces around all inlets should be sealed to prevent seepage of sediment-laden water. • Excavate sediment sumps (where needed) i to 2 ft with 2:1 side slopes around the inlet. Installation m DI Protection Type i - Filter Fabric Fence - The filter fabric fence (Type i) protection is shown in the attached figure. Similar to constructing a silt fence; see BMP SE-l, Silt Fence. Do not place filter fabric underneath the inlet grate since the collected sediment may fall into the drain inlet when the fabric is removed or replaced. 1. Excavate a trench approximately 6 in. wide and 6 in. deep along the line of the silt fence inlet protection device. 2. Place 2 in. by 2 in. wooden stakes around the perimeter of the inlet a maximum of 3 ft apart and drive them at least 18 in. into the ground or 12 in. below the bottom of the trench. The stakes must be at least 48 in. 3. Lay fabric along bottom of trench, up side of trench, and then up stakes. See SE-i, Silt Fence, for details. The maximum silt fence height around the inlet is 24 in. 4. Staple the filter fabric (for materials and specifications, see SE-i, Silt Fence) to wooden stakes. Use heavy-duty wire staples at least i in. in length. 5. Backfill the trench with gravel or compacted earth all the way around. • DI Protection Type 2 - Excavated Drop Inlet Sediment Trap - The excavated drop inlet sediment trap (Type 2) is shown in the attached figures. Install filter fabric fence in January 2003 California Stormwater BMP Handbook 3 of 9 Construction www.cabmphandbooks.com Storm Drain Inlet Protection SE-10 • Filter Fabric Fences. If the fabric becomes clogged, torn, or degrades, it should be replaced. Make sure the stakes are securely driven in the ground and are in good shape (i.e., not bent, cracked, or splintered, and are reasonably perpendicular to the ground). Replace damaged stakes. • Gravel Filters. If the gravel becomes clogged with sediment, it must be carefully removed from the inlet and either cleaned or replaced. Since cleaning gravel at a construction site may be difficult, consider using the sediment-laden stone as fill material and put fresh stone around the inlet. Inspect bags for holes, gashes, and snags, and replace bags as needed. Check gravel bags for proper arrangement and displacement. • Sediment that accumulates in the BMP must be periodically removed in order to maintain BMP effectiveness. Sediment should be removed when the sediment accumulation reaches one-third of the barrier height. Sediment removed during maintenance may be incorporated into earthwork on the site ore disposed at an appropriate location. • Remove storm drain inlet protection once the drainage area is stabilized. Clean and regrade area around the inlet and clean the inside of the storm drain inlet as it must be free of sediment and debris at the time of final inspection. References Stormwater Quality Handbooks - Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Stormwater Management Manual for The Puget Sound Basin, Washington State Department of Ecology, Public Review Draft, 1991. January 2003 California Stormwater BMP Handbook 5 of 9 Construction www.cabmphandbooks.com Storm Drain Inlet Protection SE-10 -Stabilize area and grade uniformly around perimeter Note: Remove sediment before reaching one-third full. Silt fence Per SE-01 12" Min 24" Max Section A-A Concentratedflow -x— X Sheet flow Rock filter(use if flow is concentrated) r i r n i> 1 1 L^— — i i 1 , -j«- t t ! 1 ii _j r "5 : _-— — ' < of sediment trap -Drain inlet -Geotextile Blanket -Silt fence Per SE-01 Plan PI PROTECTION TYPE 2 NOT TO SCALE Notes 1. For use in cleared and grubbed and in graded areas. 2. Shape basin so that longest inflow area faces .longest length of trap. 3. For concentrated flows, shape basin in 2:1 ratio with length oriented towards direction of flow. January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 7 of 9 Storm Drain Inlet Protection SE-10 Concrete block laid lengthwise on sides @ perimeter of opening Hardware cloth or wire mesh Runoff with sediment Filtered water Hardware cloth wire mesh Curb inlet PI PROTECTION - TYPE 4 NOT TO SCALE January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 9 of 9 Chemical Treatment SE-11 Objectives Description and Purpose Chemical treatment includes the application of chemicals to stormwater to aid in the reduction of turbidity caused by fine suspended sediment. Suitable Applications Chemical treatment can reliably provide exceptional reductions of turbidity and associated pollutants and should be considered where turbid discharges to sensitive wastes cannot be avoided using other BMPs. Typically, chemical use is limited to waters with numeric turbidity standards. Limitations The use of chemical treatment must have the advanced approval of the Regional Water Quality Control Board. • Chemical Treatment of stormwater is relatively new and unproven technology in California. • BMP has not been used often in California • Petroleum based polymers should not be used • Requires sediment basin or trailer mounted unit for chemical application • Batch treatment required, flow through continuous treatment not allowed • Requires large area EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: if Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives None C ASQA llfornla Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com Iof6 Chemical Treatment SE-11 incorporate all of the classic concepts into the design because of practical limitations at construction sites. Nonetheless, it is important to recognize the following: • The right chemical must be used at the right dosage. A dosage that is either too low or too high will not produce the lowest turbidity. There is an optimum dosage rate. This is a situation where the adage "adding more is always better" is not the case. » The coagulant must be mixed rapidly into the water to insure proper dispersion. • Experience has found that sufficient flocculation occurs in the pipe leading from the point of chemical addition to the settling or sediment basin. • Since the volume of the basin is a determinant in the amount of energy per unit volume, the size of the energy input system can be too small relative to the volume of the basin. • Care must be taken in the design of the withdrawal system to minimize outflow velocities and to prevent floe discharge. The discharge should be directed through a physical filter such as vegetated swale that would catch any unintended floe discharge. • A pH-adjusting chemical should be added into the sediment basin to control pH. Experience shows that the most common problem is low pH. Treatment System Design Chemical treatment systems should be designed as batch treatment systems using either ponds or portable trailer-mounted tanks. Flow-through continuous treatment systems are not allowed at this time. A chemical treatment system consists of the stormwater collection system (either temporary diversion or the permanent site drainage system), a sediment basin or sediment trap, pumps, a chemical feed system, treatment cells, and interconnecting piping. The treatment system should use a minimum of two lined treatment cells. Multiple treatment cells allow for clarification of treated water while other cells are being filled or emptied. Treatment cells may be basins, traps or tanks. Portable tanks may also be suitable for some sites. The following equipment should be located in an operation shed: • The chemical injector • Secondary contaminant for acid, caustic, buffering compound, and treatment chemical • Emergency shower and eyewash • Monitoring equipment which consists of a pH meter and a turbidimeter Sizing Criteria The combination of the sediment basin or other holding area and treatment capacity should be large enough to treat stormwater during multiple day storm events. See SE-2, Sediment Basin, for design criteria. Bypass should be provided around the chemical treatment system to January 2003 California Stormwater BMP Handbook 3 of 6 Construction www.cabmphandbooks.com Chemical Treatment SE-11 Operational Monitoring m pH conductivity (as a surrogate for alkalinity), turbidity, and temperature of the untreated stormwater • Total volume treated and discharged • Discharge time and flow rate • Type and amount of chemical used for pH adjustment • Amount of polymer used for treatment • Settling time Compliance Monitoring m pH and turbidity of the treated stormwater • pH and turbidity of the receiving water Bio-monitoring Treated stormwater should be tested for acute (lethal) toxicity. Bioassays should be conducted by a laboratory accredited by the State of California. The performance standard for acute toxicity is no statistically significant difference in survival between the control and 100 percent chemically treated stormwater. Acute toxicity tests should be conducted with the following species and protocols: • Fathead minnow, Pimephales promelas (96 hour static-renewal test, method: EPA/6OO/4- 9O/O2yF). Rainbow trout, Oncorhynchus mykiss (96 hour static-renewal test, method: EPA/6OO/4-9O/O27F) may be used as a substitute for fathead minnow. • Daphnid, Ceriodaphnia dubia, Daphnia pulex, or Daphnia magna (48 hour static test, method: EPA/6OO/4-9O/O27F). All toxicity tests should meet quality assurance criteria and test conditions in the most recent versions of the EPA test method. Bioassays should be performed on the first five batches and on every tenth batch thereafter or as otherwise approved by the RWQCB. Failure to meet the performance standard should be immediately reported to the RWQCB. Discharge Compliance: Prior to discharge, each batch of treated stormwater must be sampled and tested for compliance with pH and turbidity limits. These limits may be established by the water quality standards or a site-specific discharge permit. Sampling and testing for other pollutants may also be necessary at some sites. Turbidity must be within 5 NTUs of the background turbidity. Background is measured in the receiving water, upstream from the treatment process discharge point. pH must be within the range of 6.5 to 8.5 standard units and not cause a change in the pH of the receiving water of more than 0.2 standard units. It is often January 2003 California Stormwater BMP Handbook 5 of 6 Construction www.cabmphandbooks.com Wind Erosion Control WE-1 Description and Purpose Wind erosion or dust control consists of applying water or other dust palliatives as necessary to prevent or alleviate dust nuisance generated by construction activities. Covering small stockpiles or areas is an alternative to applying water or other dust palliatives. Suitable Applications Wind erosion control BMPs are suitable during the following construction activities: • Construction vehicle traffic on unpaved roads • Drilling and blasting activities • Sediment tracking onto paved roads • Soils and debris storage piles • Batch drop from front-end loaders • Areas with unstabilized soil • Final grading/site stabilization Limitations • Watering prevents dust only for a short period and should be applied daily (or more often) to be effective. • Over watering may cause erosion. Objectives EC Erosion Control SE Sediment Control TC Tracking Control WE Wind Erosion Control Non-StormwaterNSManagement Control .._,. Waste Management and Materials Pollution Control Legend: J Primary Objective / Secondary Objective Targeted Constituents Sediment t Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives None ASQA California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 5 Wind Erosion Control WE-1 Dust Control Practices Dust control BMPs generally stabilize exposed surfaces and minimize activities that suspend or track dust particles. The following table shows dust control practices that can be applied to site conditions that cause dust. For heavily traveled and disturbed areas, wet suppression (watering), chemical dust suppression, gravel asphalt surfacing, temporary gravel construction entrances, equipment wash-out areas, and haul truck covers can be employed as dust control applications. Permanent or temporary vegetation and mulching can be employed for areas of occasional or no construction traffic. Preventive measures would include minimizing surface areas to be disturbed, limiting onsite vehicle traffic to 15 mph, and controlling the number and activity of vehicles on a site at any given time. SITE CONDITION Disturbed Areas not Subject to Traffic Disturbed Areas Subject to Traffic Material Stock Pile Stabilization Demolition Clearing/ Excavation Truck Traffic on Unpaved Roads Mud/Dirt Carry Out DUST CONTROIPRACTICES Permanent Vegetation X Mulching X Wet Suppression (Watering) X X X X X X Chemical Dust Suppression X X X X X Gravel or Asphalt X X X X Silt Fences X X Temporary Gravel Construction Entrances/Equipmen Wash Down X X X X Haul Truck Covers X X Minimize Extent of Disturbed Area X X X X Additional preventive measures include: • Schedule construction activities to minimize exposed area (EC-i, Scheduling). • Quickly stabilize exposed soils using vegetation, mulching, spray-on adhesives, calcium chloride, sprinkling, and stone/gravel layering. • Identify and stabilize key access points prior to commencement of construction. • Minimize the impact of dust by anticipating the direction of prevailing winds. • Direct most construction traffic to stabilized roadways within the project site. • Water should be applied by means of pressure-type distributors or pipelines equipped with a spray system or hoses and nozzles that will ensure even distribution. • All distribution equipment should be equipped with a positive means of shutoff. • Unless water is applied by means of pipelines, at least one mobile unit should be available at all times to apply water or dust palliative to the project. January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 3 of 5 Wind Erosion Control WE-1 Caltrans, Standard Specifications, Sections 10, "Dust Control"; Section 17, "Watering"; and Section 18, "Dust Palliative". Prospects for Attaining the State Ambient Air Quality Standards for Suspended Particulate Matter (PMio), Visibility Reducing Particles, Sulfates, Lead, and Hydrogen Sulfide, California Air Resources Board, April 1991. Stormwater Quality Handbooks Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. January 2003 California Stormwater BMP Handbook 5 of 5 Construction www.cabmphandbooks.com Stabilized Construction Entrance/Exit TC-1 Objectives Description and Purpose A stabilized construction access is defined by a point of entrance/exit to a construction site that is stabilized to reduce the tracking of mud and dirt onto public roads by construction vehicles. Suitable Applications Use at construction sites: • Where dirt or mud can be tracked onto public roads. • Adjacent to water bodies. • Where poor soils are encountered. • Where dust is a problem during dry weather conditions. Limitations • Entrances and exits require periodic top dressing with additional stones. • This BMP should be used in conjunction with street sweeping on adjacent public right of way. • Entrances and exits should be constructed on level ground only. • Stabilized construction entrances are rather expensive to construct and when a wash rack is included, a sediment trap of some kind must also be provided to collect wash water runoff. EC SE TC WE NS Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control „... Waste Management and Materials Pollution Control Legend: if Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives None CASQA California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 6 Stabilized Construction Entrance/Exit TC-1 • If aggregate is selected, place crashed aggregate over geotextile fabric to at least 12 in. depth, or place aggregate to a depth recommended by a geotechnical engineer. A crushed aggregate greater than 3 in. but smaller than 6 in. should be used. • Designate combination or single purpose entrances and exits to the construction site. • Require that all employees, subcontractors, and suppliers utilize the stabilized construction access. • Implement SE-7, Street Sweeping and Vacuuming, as needed. • All exit locations intended to be used for more than a two-week period should have stabilized construction entrance/exit BMPs. Inspection and Maintenance • Inspect and verify that activity-based BMPs are in place prior to the commencement of associated activities. While activities associated with the BMPs are under way, inspect weekly during the rainy season and of two-week intervals in the non-rainy season to verify continued BMP implementation. • Inspect local roads adjacent to the site daily. Sweep or vacuum to remove visible accumulated sediment. • Remove aggregate, separate and dispose of sediment if construction entrance/exit is clogged with sediment. • Keep all temporary roadway ditches clear. • Check for damage and repair as needed. • Replace gravel material when surface voids are visible. • Remove all sediment deposited on paved roadways within 24 hours. • Remove gravel and filter fabric at completion of construction Costs Average annual cost for installation and maintenance may vary from $1,200 to $4,800 each, averaging $2,400 per entrance. Costs will increase with addition of washing rack, and sediment trap. With wash rack, costs range from $1,200 - $6,000 each, averaging $3,600 per entrance. References Manual of Standards of Erosion and Sediment Control Measures, Association of Bay Area Governments, May 1995. National Management Measures to Control Nonpoint Source Pollution from Urban Areas, USEPA Agency, 2002. Proposed Guidance Specifying Management Measures for Sources of Nonpoint Pollution in Coastal Waters, Work Group Working Paper, USEPA, April 1992. January 2003 California Stormwater BMP Handbook 3 of 6 Construction www.cabmphandbooks.com Stabilized Construction Entrance/Exit TC-1 _Crushed aggregate greater than 3" but smaller than 6" Original grade 12 " Min, unless otherwise specified by a soils engineer SECTION B-B NTS NOTE: :| Construct sediment barrier '• and channelize runoff to sediment trapping device Temporary pipe culvert as needed Width as required to accomodate anticipated traffic Match Existing Grade 50' Min or four times the circumference of the largest construction vehicle tire, whichever is greater PLAN NTS January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 5 of 6 Stabilized Construction Roadway TC-2 Description and Purpose Access roads, subdivision roads, parking areas, and other onsite vehicle transportation routes should be stabilized immediately after grading, and frequently maintained to prevent erosion and control dust. Suitable Applications This BMP should be applied for the following conditions: • Temporary Construction Traffic: Phased construction projects and offsite road access - Construction during wet weather • Construction roadways and detour roads: - Where mud tracking is a problem during wet weather Where dust is a problem during dry weather Adjacent to water bodies Where poor soils are encountered Limitations • The roadway must be removed or paved when construction is complete. Objectives EC Erosion Control SE Sediment Control TC Tracking Control WE Wind Erosion Control Non-StormwaterNSManagement Control ....... Waste Management and Materials Pollution Control Legend: v Primary Objective •/ Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Aiternatives None California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 4 Stabilized Construction Roadway TC-2 • Stabilize roadway using aggregate, asphalt concrete, or concrete based on longevity, required performance, and site conditions. The use of cold mix asphalt or asphalt concrete (AC) grindings for stabilized construction roadway is not allowed. • Coordinate materials with those used for stabilized construction entrance/exit points. • If aggregate is selected, place crushed aggregate over geotextile fabric to at least 12 in. depth. A crushed aggregate greater than 3 in. but smaller than 6 in. should be used. Inspection and Maintenance • Inspect and verify that activity-based BMPs are in place prior to the commencement of associated activities. While activities associated with the BMP are under way, impact weekly during the rainy season and of two-week intervals in the non-rainy season to verify continued BMP implementation. • Keep all temporary roadway ditches clear. • When no longer required, remove stabilized construction roadway and re-grade and repair slopes. • Periodically apply additional aggregate on gravel roads. • Active dirt construction roads are commonly watered three or more times per day during the dry season. Costs Gravel construction roads are moderately expensive, but cost is often balanced by reductions in construction delay. No additional costs for dust control on construction roads should be required above that needed to meet local air quality requirements. References Blueprint for a Clean Bay: Best Management Practices to Prevent Stormwater Pollution from Construction Related Activities; Santa Clara Valley Nonpoint Source Pollution Control Program, 1995- Coastal Nonpoint Pollution Control Program; Program Development and Approval Guidance, Working Group, Working Paper; USEPA, April 1992. Manual of Standards of Erosion and Sediment Control Measures, Association of Bay Area Governments, May 1995. Stormwater Quality Handbooks Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Stormwater Management for Construction Activities, Developing Pollution Prevention Plans and Best Management Practices, EPA 832-^92005; USEPA, April 1992. Stormwater Management of the Puget Sound Basin, Technical Manual, Publication #91-75, Washington State Department of Ecology, February 1992. January 2003 California Stormwater BMP Handbook 3 of 4 Construction www.cabmphandbooks.com Entrance/Outlet Tire Wash TC-3 Description and Purpose A tire wash is an area located at stabilized construction access points to remove sediment from tires and under carriages and to prevent sediment from being transported onto public roadways. Suitable Applications Tire washes may be used on construction sites where dirt and mud tracking onto public roads by construction vehicles may occur. Limitations • The tire wash requires a supply of wash water. • A turnout or doublewide exit is required to avoid having entering vehicles drive through the wash area. • Do not use where wet tire trucks leaving the site leave the road dangerously slick. Implementation • Incorporate with a stabilized construction entrance/exit. See TC-i, Stabilized Construction Entrance/Exit. • Construct on level ground when possible, on a pad of coarse aggregate greater than 3 in. but smaller than 6 in. A geotextile fabric should be placed below the aggregate. • Wash rack should be designed and constructed/manufactured for anticipated traffic loads. Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: J Primary Objective •/ Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives TC-1 Stabilized Construction Entrance/Exit CASQA •California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 3 Entrance/Outlet Tire Wash TC-3 Crushed aggregate greater than 3" but smaller than 6". Corrugated steel panels /- Original grade 12" Min, unless otherwise specified by a soils engineer Filter fabric SECTION A-A NOT TO SCALE .Crushed aggregate greater than 3" but smaller than 6" Filter fabric Original grade 12" Min, unless otherwise specified by a soils engineer SECTION B-B NTS Ditch to carry runoff — to a sediment trapping device NOTE: Many designs can be field fabricated, or fabricated units may be used. Water supply & hose TYPICAL TIRE WASH NOT TO SCALE January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 3 of 3 Section 4 Non-Stormwater Management and Material Management BMPs 4.1 Non-Stormwater Management BMPs The Construction General Permit prohibits the discharge of materials other than stormwater and authorized non-stormwater discharges. It is recognized that certain non-stormwater discharges may be necessary for the completion of construction projects. Such discharges include but are not limited to irrigation of vegetative erosion control measures, pipe flushing and testing, and street cleaning. Non-stormwater management BMPs are source control BMPs that prevent pollution by limiting or reducing potential pollutants at their source or eliminating off-site discharge. These practices involve day-to-day operations of the construction site and are usually under the control of the contractor. These BMPs are also referred to as "good housekeeping practices" which involve keeping a clean, orderly construction site. Non-stormwater management BMPs also include procedures and practices designed to minimize or eliminate the discharge of pollutants from vehicle and equipment cleaning, fueling, and maintenance operations to stormwater drainage systems or to watercourses. Table 4-1 lists the non-stormwater management BMPs. All these BMPs must be implemented depending on the conditions and applicability of deployment described as part of the BMP. It is recommended that owners and contractors be vigilant regarding implementation of these BMPs, including making their implementation a condition of continued employment, and part of all prime and subcontract agreements. By doing so, the chance of inadvertent violation by an uncaring individual can be prevented, potentially saving thousands of dollars in fines and project delays. Also, if procedures are not properly implemented and/or if BMPs are compromised then the discharge is subject to sampling and analysis requirements contained in the General Permit. Table 4-1 Non-Stormwater Management BMPs BMP* NS-i NS-2 NS-3 NS-4 NS-5 NS-6 NS-7 NS-8 NS-9 NS-io NS-ii NS-12 NS-13 NS-14 NS-15 NS-i6 BMP Name Water Conservation Practices Dewatering Operations Paving and Grinding Operations Temporary Stream Crossing Clear Water Diversion Illicit Connection/Discharge Potable Water/Irrigation Vehicle and Equipment Cleaning Vehicle and Equipment Fueling Vehicle and Equipment Maintenance Pile Driving Operations Concrete Curing Concrete Finishing Material and Equipment Use Demolition Adjacent to Water Temporary Batch Plants January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 4-1 Section 4 Non-Stormwater Management and Material Management BMPs 4.3 Fact Sheet Format A BMP fact sheet is a short document that gives all the information about a particular BMP. Typically each fact sheet contains the information outlined in Figure 4-1. Completed fact sheets for each of the above activities are provided in Section 4.4. The fact sheets also contain side bar presentations with information on BMP objectives, targeted constituents, removal effectiveness, and potential alternatives. 4.4 BMP Fact Sheets NS-xx Example Fact Sheet Description and Purpose Suitable Applications Limitations Implementation Costs Inspection and Maintenance References Figure 4-1 Example Fact Sheet BMP Fact Sheets for non-stormwater management and waste management and materials pollution control follow. The BMP fact sheets are individually page numbered and are suitable for photocopying and inclusions in SWPPPs. Fresh copies of the fact sheets can be individually downloaded from the Caltrans Stormwater BMP Handbook website at www.cabmphandbooks.com. January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 4-3 Water Conservation Practices NS-1 Objectives Description and Purpose Water conservation practices are activities that use water during the construction of a project in a manner that avoids causing erosion and the transport of pollutants offsite. These practices can reduce or eliminate non-stormwater discharges. Suitable Applications Water conservation practices are suitable for all construction sites where water is used, including piped water, metered water, trucked water, and water from a reservoir, Limitations • None identified. Implementation • Keep water equipment in good working condition. • Stabilize water truck filling area. • Repair water leaks promptly. • Washing of vehicles and equipment on the construction site is discouraged. • Avoid using water to clean construction areas. If water must be used for cleaning or surface preparation, surface should be swept and vacuumed first to remove dirt. This will minimize amount of water required. EC Erosion Control SE Sediment Control TC Tracking Control WE Wind Erosion Control Non-StormwaterNSManagement Control ....... Waste Management and Materials Pollution Control Legend: </ Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives None CASQA California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 2 Dewatering Operations NS-2 Description and Purpose Dewatering operations are practices that manage the discharge of pollutants when non-stormwater and accumulated precipitation must be removed from a work location so that construction work may be accomplished. Suitable Applications These practices are implemented for discharges of non- stormwater from construction sites. Non-stormwaters include, but are not limited to, groundwater, water from cofferdams, water diversions, and waters used during construction activities that must be removed from a work area. Practices identified in this section are also appropriate for implementation when managing the removal of accumulated precipitation (stormwater) from depressed areas at a construction site. Limitations • Site conditions will dictate design and use of dewatering operations. • The controls discussed in this best management practice (BMP) address sediment only. • The controls detailed in this BMP only allow for minimal settling time for sediment particles. Use only when site conditions restrict the use of the other control methods. • Dewatering operations will require, and must comply with, applicable local permits. Objectives EC SE TC WE NS WM Erosion Control Sediment Control •/ Tracking Control Wind Erosion Control Non-Stormwater / Management Control Waste Management and Materials Pollution Control Legend: </ Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease 1 Organics Potential Alternatives SE-5: Fiber Roll SE-6: Gravel Bag Berm SE-9: Straw Bale Barrier California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 11 Dewatering Operations _ NS-2 Maintenance: • Maintenance is required for safety fencing, vegetation, embankment, inlet and outfall structures, as well as other features. • Removal of sediment is required when the storage volume is reduced by one-half. Sediment Trap (See also Description: m A sediment trap is a temporary basin formed by excavation and/or construction of an earthen embankment across a waterway or low drainage area to detain sediment-laden runoff and allow sediment to settle out before discharging. Sediment traps are generally smaller than Sediment Basins (SE-2). Appropriate Applications: Effective for the removal of large and medium sized particles (sand and gravel) and some metals that settle out with the sediment. Implementation: m Excavation and construction of related facilities is required. • Trap inlets should be located to maximize the travel distance to the trap outlet. • Use rock or vegetation to protect the trap outlets against erosion. Maintenance: • Maintenance is required for vegetation, embankment, inlet and outfall structures, as well as other features. • Removal of sediment is required when the storage volume is reduced by one-third. January 2003 California Stormwater BMP Handbook 3 of 11 Construction www.cabmphandbooks.com Dewatering Operations NS-2 Dewatering Tanks Description: • A dewatering tank removes debris and sediment. Flow enters the tank through the top, passes through a fabric filter, and is discharged through the bottom of the tank. The filter separates the solids from the liquids. Appropriate Applications: m The tank removes trash, gravel, sand, and silt, some visible oil and grease, and some metals (removed with sediment). To achieve high levels of flow, multiple tanks can be used in parallel. If additional treatment is desired, the tanks can be placed in series or as pre- treatment for other methods. Implementa tion: • Tanks are delivered to the site by the vendor, who can provide assistance with set-up and operation. • Tank size will depend on flow volume, constituents of concern, and residency period required. Vendors should be consulted to appropriately size tank. Maintenance: • Periodic cleaning is required based on visual inspection or reduced flow. • Oil and grease disposal must be by licensed waste disposal company. January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 5 of 11 Dewatering Operations NS-2 Sand Media Particulate Filter Description: m Water is treated by passing it through canisters filled with sand media. Generally, sand filters provide a final level of treatment. They are often used as a secondary or higher level of treatment after a significant amount of sediment and other pollutants have been removed using other methods. Appropriate Applications: m Effective for the removal of trash, gravel, sand, and silt and some metals, as well as the reduction of biochemical oxygen demand (BOD) and turbidity. • Sand filters can be used for stand-alone treatment or in conjunction with bag and cartridge filtration if further treatment is required. • Sand filters can also be used to provide additional treatment to water treated via settling or basic filtration. Implementation: m The filters require delivery to the site and initial set up. The vendor can provide assistance with installation and operation. Maintenance: m The filters require regular service to monitor and maintain the level of the sand media. If subjected to high loading rates, filters can plug quickly. • Venders generally provide data on maximum head loss through the filter. The filter should be monitored daily while in use, and cleaned when head loss reaches target levels. • If cleaned by backwashing, the backwash water may need to be hauled away for disposal, or returned to the upper end of the treatment train for another pass through the series of dewatering BMPs. January 2003 California Stormwater BMP Handbook 7 of 11 Construction www.cabmphandbooks.com Dewatering Operations NS-2 Cartridge Filter Description: m Cartridge filters provide a high degree of pollutant removal by utilizing a number of individual cartridges as part of a larger filtering unit. They are often used as a secondary or higher (polishing) level of treatment after a significant amount of sediment and other pollutants are removed. Units come with various cartridge configurations (for use in series with bag filters) or with a larger single cartridge filtration unit (with multiple filters within). Appropriate Applications: • Effective for the removal of sediment (sand, silt, and some clays) and metals, as well as the reduction of BOD, turbidity, and hydrocarbons. Hydrocarbons can effectively be removed with special resin cartridges. • Filters can be used to provide secondary treatment to water treated via settling or basic filtration. Implementation: • The filters require delivery to the site and initial set up. The vendor can provide assistance. Maintenance: • The cartridges require replacement when the pressure differential equals or exceeds the manufacturer's recommendation. Costs • Sediment controls are low to high cost measures depending on the dewatering system that is selected. Pressurized filters tend to be more expensive than gravity settling, but are often more effective. Simple tanks are generally rented on a long-term basis (one or more months) and can range from $360 per month for a 1,000 gallon tank to $2,660 per month for a 10,000 gallon tank. Mobilization and demobilization costs vary considerably. Inspection and Maintenance • Inspect and verify that activity-based BMPs are in place prior to the commencement of associated activities. While activities associated with the BMP are under way, inspect weekly during the rainy season and at two-week intervals in the non-rainy season to verify continued BMP implementation. January 2003 California Stormwater BMP Handbook 9 of 11 Construction www.cabmphandbooks.com Dewatering Operations NS-2 Does water have an odor, discoloration other than \ Yes sediment, or an oily sheen or foam on the surface? Assess water quality and eliminate discharge flow rate and volume Contact a stormwater quality professional for assistance Is the site location outside of RWQCB Regions 1 and 2, and does the discharge solely consistof accumulatedprecipitation? Is itfeasible to manage water without discharge to a storm drain or water body? No, Itis in Region 1 or 2, or is groundwater or cofferdam/ diversion dewatering Retain water on site: Infiltrate/Evaporate/ Reuse : Discharge by j agreement to a I sanitary sewer I -* •""••••"'-•- i \ ' [Discharge by | | agreement to 1 adjacent land/facility 1 1Jn ^ Transport off sitefor disposal Dewatering Operations Management Flow Chart Dewatering of groundwater, cofferdams, or diversions, and discharge of accumulated precipitation is addressed in this flow chart. Contact a stormwater quality professional for guidance on all other discharges. Notes: MGD Million Gallons per Day NPDES National Pollutant Discharge Elimination System RWQCB Regional Water Quality Control Board Yes, accumulated precipitation in , RWQCB /. ls . Regions 3-9 / dewate"n9" ' regulated by RWQCB permit? Willthe dischargecontinue for more than 4 months or exceed 0.25 MGD? Consult RWQCB for dischargerequirements Notify RWQBC of proposed; dewatering discharge and provide any available analytical testing or qualitative assessment information Discharge water to storm drain or water body (Maintain monitoring records)with SWPPP and provide to RWQCB if required Figure 1 Operations Flow Chart January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 11 of 11 Paving and Grinding Operations NS-3 Description and Purpose Prevent or reduce the discharge of pollutants from paving operations, using measures to prevent runon and runoff pollution, properly disposing of wastes, and training employees and subcontractors. Suitable Applications These procedures are implemented where paving, surfacing, resurfacing, or sawcutting, may pollute stormwater runoff or discharge to the storm drain system or watercourses. Limitations • Finer solids are not effectively removed by filtration systems. • Paving opportunities may be limited during wet weather. Implementation General m Avoid paving during the wet season when feasible. • Reschedule paving and grinding activities if rain is in the forecast. • Train employees and sub-contractors in pollution prevention and reduction. • Store materials away from drainage courses to prevent stormwater runon (see WM-i, Material Delivery and Storage). Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater / Management Control Waste Management and y Materials Pollution Control Legend: if Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease > Organics Potential Alternatives None CASQA alifornla Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 4 Paving and Grinding Operations NS-3 Do not allow sand or gravel placed over new asphalt to wash into storm drains, streets, or creeks. Vacuum or sweep loose sand and gravel and properly dispose of this waste by referring to WM-5, Solid Waste Management. Old asphalt must be disposed of properly. Collect and remove all broken asphalt from the site and recycle whenever possible. Portland Cement Concrete Paving • Do not wash sweepings from exposed aggregate concrete into a storm drain system. Collect and return to aggregate base stockpile or dispose of properly. • Allow aggregate rinse to settle. Then, either allow rinse water to dry in a temporary pit as described in WM-8, Concrete Waste Management, or pump the water to the sanitary sewer if allowed by the local wastewater authority. Sealing Operations • During chip seal application and sweeping operations, petroleum or petroleum covered aggregate must not be allowed to enter any storm drain or water courses. Apply temporary perimeter controls until structure is stabilized. • Drainage inlet structures and manholes should be covered with filter fabric during application of seal coat, tack coat, slurry seal, and fog seal. • Seal coat, tack coat, slurry seal, or fog seal should not be applied if rainfall is predicted to occur during the application or curing period. Paving Equipment m Leaks and spills from paving equipment can contain toxic levels of heavy metals and oil and grease. Place drip pans or absorbent materials under paving equipment when not in use. Clean up spills with absorbent materials rather than burying. See NS-io, Vehicle and Equipment Maintenance, WM-4, Spill Prevention and Control, and WM-io, Liquid Waste Management. • Substances used to coat asphalt transport trucks, and asphalt spreading equipment should not contain soap and should be non-foaming and non-toxic. • Use only non-toxic substances to coat asphalt transport trucks and asphalt spreading equipment. • Paving equipment parked onsite should be parked over plastic to prevent soil contamination. • Clean asphalt coated equipment offsite whenever possible. When cleaning dry, hardened asphalt from equipment, manage hardened asphalt debris as described in WM-5, Solid Waste Management. Any cleaning onsite should follow NS-8, Vehicle and Equipment Cleaning. January 2003 California Stormwater BMP Handbook 3 of 4 Construction www.cabmphandbooks.com Temporary Stream Crossing NS-4 Objectives EC SE TC WE NS WM Erosion Control ^ Sediment Control J Tracking Control <f Wind Erosion Control Non-Stormwater / Management Control Waste Management and Materials Pollution Control Legend: * Primary Objective / Secondary Objective Description and Purpose A temporary stream crossing is a temporary culvert, ford or bridge placed across a waterway to provide access for construction purposes for a period of less than one year. Temporary access crossings are not intended to maintain traffic for the public. The temporary access will eliminate erosion and downstream sedimentation caused by vehicles. Suitable Applications Temporary stream crossings should be installed at all designated crossings of perennial and intermittent streams on the construction site, as well as for dry channels that may be significantly eroded by construction traffic. Temporary streams crossings are installed at sites: • Where appropriate permits have been secured (404 Permits, and 401 Certifications) • Where construction equipment or vehicles need to frequently cross a waterway • When alternate access routes impose significant constraints • When crossing perennial streams or waterways causes significant erosion • Where construction activities will not last longer than one year Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives None fiJLSQ /I California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 8 Temporary Stream Crossing NS-4 • Areas where the side slopes from site runoff will not spill into the side slopes of the crossing. The following types of temporary stream crossings should be considered: • Culverts - A temporary culvert is effective in controlling erosion but will cause erosion during installation and removal. A temporary culvert can be easily constructed and allows for heavy equipment loads. • Fords - Appropriate during the dry season in arid areas. Used on dry washes and ephemeral streams, and low-flow perennial streams. CCS, a type of ford crossing, is also appropriate for use in streams that would benefit from an influx of gravels. A temporary ford provides little sediment and erosion control and is ineffective in controlling erosion in the stream channel. A temporary ford is the least expensive stream crossing and allows for maximum load limits. It also offers very low maintenance. Fords are more appropriate during the dry ice season and in arid areas of California. • Bridges - Appropriate for streams with high flow velocities, steep gradients and where temporary restrictions in the channel are not allowed. Design During the long summer construction season in much of California, rainfall is infrequent and many streams are dry. Under these conditions, a temporary ford may be sufficient. A ford is not appropriate if construction will continue through the winter rainy season, if summer thunderstorms are likely, or if the stream flows during most of the year. Temporary culverts and bridges should then be considered and, if used, should be sized to pass a significant design storm (i.e., at least a lo-year storm). The temporary stream crossing should be protected against erosion, both to prevent excessive sedimentation in the stream and to prevent washout of the crossing. Design and installation requires knowledge of stream flows and soil strength. Designs should be prepared under direction of, and approved by, a registered civil engineer and for bridges, a registered structural engineer. Both hydraulic and construction loading requirements should be considered with the following: • Comply with any special requirements for culvert and bridge crossings, particularly if the temporary stream crossing will remain through the rainy season. • Provide stability in the crossing and adjacent areas to withstand the design flow. The design flow and safety factor should be selected based on careful evaluation of the risks due to over topping, flow backups, or washout. • Install sediment traps immediately downstream of crossings to capture sediments. See SE-3, Sediment Trap. • Avoid oil or other potentially hazardous materials for surface treatment. • Culverts are relatively easy to construct and able to support heavy equipment loads. • Fords are the least expensive of the crossings, with maximum load limits. January 2003 California Stormwater BMP Handbook 3 of 8 Construction www.cabmphandbooks.com Temporary Stream Crossing NS-4 • Disturbance or removal of vegetation should not exceed the minimum necessary to complete operations. Precautions should be taken to avoid damage to vegetation by people or equipment. Disturbed vegetation should be replaced with the appropriate soil stabilization measures. • Riparian vegetation, when removed pursuant to the provisions of the work, should be cut off no lower than ground level to promote rapid re-growth. Access roads and work areas built over riparian vegetation should be covered by a sufficient layer of clean river run cobble to prevent damage to the underlying soil and root structure. The cobble must be removed upon completion of project activities. • Conceptual temporary stream crossings are shown in the attached figures. Costs Caltrans Construction Cost index for temporary bridge crossings is $45-$95/ft2. Inspection and Maintenance • Inspect and verify that activity-based BMPs are in place prior to the commencement of associated activities. While activities associated with the BMP are under way, inspect weekly during the rainy season and at two week intervals in the non-rainy season to verify continued BMP implementation. • Check for blockage in the channel, sediment buildup or trapped debris in culverts, blockage behind fords or under bridges • Check for erosion of abutments, channel scour, riprap displacement, or piping in the soil • Check for structural weakening of the temporary crossings, such as cracks, and undermining of foundations and abutments • Remove sediment that collects behind fords, in culverts, and under bridges periodically • Replace lost or displaced aggregate from inlets and outlets of culverts and cellular confinement systems • Remove temporary crossing promptly when it is no longer needed References California Bank and Shore Rock Slope Protection Design - Practitioners Guide and Field Evaluations of Riprap Methods, Caltrans Study No. FgoTLos, October 2000. Stormwater Quality Handbooks - Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. January 2003 California Stormwater BMP Handbook 5 of 8 Construction www.cabmphandbooks.com Temporary Stream Crossing NS-4 1/2 Diameter of pipe 12", or as needed to support loads, whichever is greater. Coarse aggregate Capacity of pipe culverts together = design flow + safety factor Earth fill covered by large angular rock, upstream and downstream. Soil Binder EC-3, EC-5EC-6, EC-7 Approach stabilized with coarse aggregate Large angular rock over earth fill, P^OC ELEVATION Engineering fabric Approach stabilized with coarse aggregate downstream. Diversion and/or swale Top of bank Diversion and/or swale Top of bonk •Stream channel PLAN VIEW TYPICAL CULVERT CROSSING NOT TO SCALE January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 7 of 8 Clear Water Diversion NS-5 Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater / Management Control Waste Management and Materials Pollution Control Legend: </ Primary Objective / Secondary Objective Description and Purpose Clear water diversion consists of a system of structures and measures that intercept clear surface water runoff upstream of a project, transport it around the work area, and discharge it downstream with minimal water quality degradation from either the project construction operations or the construction of the diversion. Clear water diversions are used in a waterway to enclose a construction area and reduce sediment pollution from construction work occurring in or adjacent to water. Structures commonly used as part of this system include diversion ditches, berrns, dikes, slope drains, rock, gravel bags, wood, aqua barriers, cofferdams, filter fabric or turbidity curtains, drainage and interceptor swales, pipes, or flumes. Suitable Applications A clear water diversion is typically implemented where appropriate permits (1601 Agreement) have been secured and work must be performed in a flowing stream or water body. • Clear water diversions are appropriate for isolating construction activities occurring within or near a water body such as streambank stabilization, or culvert, bridge, pier or abutment installation. They may also be used in combination with other methods, such as clear water bypasses and/or pumps. • Pumped diversions are suitable for intermittent and low flow streams. • Excavation of a temporary bypass channel, or passing the flow through a heavy pipe (called a "flume") with a trench excavated Targeted Constituents Sediment i Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives None C A S California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 10 Clear Water Diversion NS-5 • Excavation equipment buckets may reach out into the water for the purpose of removing or placing fill materials. Only the bucket of the crane/ excavator/backhoe may operate in a water body. The main body of the crane/excavator/backhoe should not enter the water body except as necessary to cross the stream to access the work site. • Stationary equipment such as motors and pumps located within or adjacent to a water body, should be positioned over drip pans. • When any artificial obstruction is being constructed, maintained, or placed in operation, sufficient water should, at all times, be allowed to pass downstream to maintain aquatic life. • Equipment should not be parked below the high water mark unless allowed by a permit. • Disturbance or removal of vegetation should not exceed the minimum necessary to complete operations. Precautions should be taken to avoid damage to vegetation by people or equipment. Disturbed vegetation should be replaced with the appropriate erosion control measures. • Riparian vegetation approved for trimming as part of the project should be cut off no lower than ground level to promote rapid re-growth. Access roads and work areas built over riparian vegetation should be covered by a sufficient layer of clean river run cobble to prevent damage to the underlying soil and root structure. The cobble should be removed upon completion of project activities. • Drip pans should be placed under all vehicles and equipment placed on docks, barges, or other structures over water bodies when the vehicle or equipment is planned to be idle for more than i hour. • Where possible, avoid or minimize diversion and encroachment impacts by scheduling construction during periods of low flow or when the stream is dry. Scheduling should also consider seasonal releases of water from dams, fish migration and spawning seasons, and water demands due to crop irrigation. • Construct diversion structures with materials free of potential pollutants such as soil, silt, sand, clay, grease, or oil. Temporary Diversions and Encroachments • Construct diversion channels in accordance with EC-9, Earth Dikes and Drainage Swales. • In high flow velocity areas, stabilize slopes of embankments and diversion ditches using an appropriate liner, in accordance with EC-y, Geotextiles and Mats, or use rock slope protection. • Where appropriate, use natural streambed materials such as large cobbles and boulders for temporary embankment and slope protection, or other temporary soil stabilization methods. • Provide for velocity dissipation at transitions in the diversion, such as the point where the stream is diverted to the channel and the point where the diverted stream is returned to its natural channel. See also EC-io, Velocity Dissipation Devices. January 2003 California Stormwater BMP Handbook 3 of 10 Construction www.cabmphandbooks.com Clear Water Diversion NS-5 • Filter fabric and turbidity curtain isolation installation methods can be found in the specific technique descriptions that follow. Filter Fabric Isolation Technique Definition and Purpose A filter fabric isolation structure is a temporary structure built into a waterway to enclose a construction area and reduce sediment pollution from construction work in or adjacent to water. This structure is composed of filter fabric, gravel bags, and steel t-posts. Appropriate Applications • Filter fabric may be used for construction activities such as streambank stabilization, or culvert, bridge, pier or abutment installation. It may also be used in combination with other methods, such as clean water bypasses and/or pumps. • Filter fabric isolation is relatively inexpensive. This method involves placement of gravel bags or continuous berms to 'key-in' the fabric, and subsequently staking the fabric in place. • If spawning gravel is used, all other components of the isolation can be removed from the stream, and the gravel may be spread out and left as salmonid spawning habitat if approved in the permit. Whether spawning gravel or other types of gravel are used, only clean washed gravel should be used as infill for the gravel bags or continuous berm. • This method should be used in relatively calm water, and can be used in smaller streams. This is not a dewatering method, but rather a sediment isolation method. • Water levels inside and outside the fabric curtain must be about the same, as differential heads will cause the curtain to collapse. Limitations • Do not use if the installation, maintenance and removal of the structures will disturb sensitive aquatic species of concern. • Filter fabrics are not appropriate for projects where dewatering is necessary. • Filter fabrics are not appropriate to completely dam stream flow. Design and Installation • For the filter fabric isolation method, a non-woven or heavy-duty fabric is recommended over standard silt fence. Using rolled geotextiles allows non-standard widths to be used. • Anchor filter fabric with gravel bags filled with clean, washed gravel. Do not use sand. If a bag should split open, the gravel can be left in the stream, where it can provide aquatic habitat benefits. If a sandbag splits open in a watercourse, the sand could cause a decrease in water quality, and could bury sensitive aquatic habitat. • Another anchor alternative is a continuous berm, made with the Continuous Berm Machine. This is a gravel-filled bag that can be made in very long segments. The length of the berms is usually limited to 18 ft for ease of handling (otherwise, it gets too heavy to move). January 2003 California Stormwater BMP Handbook 5 of 10 Construction www.cabmphandbooks.com Clear Water Diversion NS-5 desirable for the curtain to reach the bottom in an active-water situation, a pervious filter fabric may be used for the bottom i ft. • The top of the curtain should consist of flexible flotation buoys, and the bottom should be held down by a load line incorporated into the curtain fabric. The fabric should be a brightly colored impervious mesh. • The curtain should be held in place by anchors placed at least every 100 ft. • First, place the anchors, then tow the fabric out in a furled condition, and connect to the anchors. The anchors should be connected to the flotation devices, and not to the bottom of the curtain. Once in place, cut the furling lines, and allow the bottom of the curtain to sink. • Consideration must be given to the probable outcome of the removal procedure. It must be determined if it will create more of a sediment problem through re-suspension of the particles or by accidental dumping of material during removal. It is recommended that the soil particles trapped by the turbidity curtain only be removed if there has been a significant change in the original contours of the affected area in the watercourse. • Particles should always be allowed to settle for a minimum of 6 to 12 hours prior to their removal or prior to removal of the turbidity curtain. Maintenance and Inspection: m The curtain should be inspected for holes or other problems, and any repairs needed should be made promptly. • Allow sediment to settle for 6 to 12 hours prior to removal of sediment or curtain. This means that after removing sediment, wait an additional 6 to 12 hours before removing the curtain. • To remove, install furling lines along the curtain, detach from anchors, and tow out of the water. K-rail River Isolation Definition and Purpose This temporary sediment control or stream isolation method uses K-rails to form the sediment deposition area, or to isolate the in-stream or near-bank construction area. Barriers are placed end-to-end in a pre-designed configuration and gravel-filled bags are used at the toe of the barrier and at their abutting ends to seal and prevent movement of sediment beneath or through the barrier walls. Appropriate Applications The K-rail isolation can be used in streams with higher water velocities than many other isolation techniques. • This technique is also useful at the toe of embankments, and cut or fill slopes. January 2003 California Stormwater BMP Handbook 7 of 10 Construction www.cabmphandbooks.com Clear Water Diversion NS-5 • Minor in-stream disturbance is required to install and remove dams. Advantages of Excavated Channels and Flumes m Excavated channels isolate work from water flow and allow dewatering. • Excavated channels can handle larger flows than pumps. Disadvantages of Excavated Channels and Flumes • Bypass channel or flume must be sized to handle flows, including possible floods. • Channels must be protected from erosion. • Flow diversion and re-direction with small dams involves in-stream disturbance and mobilization of sediment. Design and Installation • Installation guidelines will vary based on existing site conditions and type of diversion used. • Pump capacity must be sufficient for design flow. • A standby pump is required in case a primary pump fails. • Dam materials used to create dams upstream and downstream of diversion should be erosion resistant; materials such as steel plate, sheet pile, sandbags, continuous berms, inflatable water bladders, etc., would be acceptable. When constructing a diversion channel, begin excavation of the channel at the proposed downstream end, and work upstream. Once the watercourse to be diverted is reached and the excavated channel is stable, breach the upstream end and allow water to flow down the new channel. Once flow has been established in the diversion channel, install the diversion weir in the main channel; this will force all water to be diverted from the main channel. Inspection and Maintenance • Pumped diversions require 24 hour monitoring of pumps. • Inspect embankments and diversion channels for damage to the linings, accumulating debris, sediment buildup, and adequacy of the slope protection. Remove debris and repair linings and slope protection as required. Remove holes, gaps, or scour. • Upon completion of work, the diversion or isolation structure should be removed and flow should be redirected through the new culvert or back into the original stream channel. Recycle or reuse if applicable. • Revegetate areas disturbed by BMP removal if needed. Costs Costs of clear water diversion vary considerably and can be very high. January 2003 California Stormwater BMP Handbook 9 of 10 Construction www.cabmphandbooks.com Illicit Connection/Discharge NS-6 Description and Purpose Procedures and practices designed for construction contractors to recognize illicit connections or illegally dumped or discharged materials on a construction site and report incidents. Suitable Applications This best management practice (BMP) applies to all construction projects. Illicit connection/discharge and reporting is applicable anytime an illicit connection or discharge is discovered or illegally dumped material is found on the construction site. Limitations Illicit connections and illegal discharges or dumping, for the purposes of this BMP, refer to discharges and dumping caused by parties other than the contractor. If pre-existing hazardous materials or wastes are known to exist onsite, they should be identified in the SWPPP and handled as set forth in the SWPPP. Implementation PZanningf • Review the SWPPP. Pre-existing areas of contamination should be identified and documented in the SWPPP. • Inspect site before beginning the job for evidence of illicit connections, illegal dumping or discharges. Document any pre- existing conditions and notify the owner. Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: v Primary Objective / Secondary Objective Targeted Constituents Sediment Nutrients / Trash S Metals </ Bacteria •/ Oil and Grease </ Organics J Potential Alternatives None CASOA. lifornia Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com lof 3 Illicit Connection/Discharge NS-6 Costs Costs to look for and report illicit connections and illegal discharges and dumping are low. The best way to avoid costs associated with illicit connections and illegal discharges and dumping is to keep the project perimeters secure to prevent access to the site, to observe the site for vehicles that should not be there, and to document any waste or hazardous materials that exist onsite before taking possession of the site. Inspection and Maintenance • Inspect and verify that activity-based BMPs are in place prior to the commencement of associated activities. While activities associated with the BMP are under way, inspect weekly during the rainy season and at two-week intervals in the non-rainy season to verify continued BMP implementation. • Inspect the site regularly to check for any illegal dumping or discharge. • Prohibit employees and subcontractors from disposing of non-job related debris or materials at the construction site. • Notify the owner of any illicit connections and illegal dumping or discharge incidents at the time of discovery. References Blueprint for a Clean Bay: Best Management Practices to Prevent Stormwater Pollution from Construction Related Activities; Santa Clara Valley Nonpoint Source Pollution Control Program, 1995- Stormwater Quality Handbooks - Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Stormwater Management for Construction Activities, Developing Pollution Prevention Plans and Best Management Practices, EPA 832-^92005; USEPA, April 1992. January 2003 California Stormwater BMP Handbook 3 of 3 Construction www.cabmphandbooks.com Potable Water/Irrigation NS-7 Description and Purpose Potable Water/Irrigation consists of practices and procedures to manage the discharge of potential pollutants generated during discharges from irrigation water lines, landscape irrigation, lawn or garden watering, planned and unplanned discharges from potable water sources, water line flushing, and hydrant flushing. Suitable Applications Implement this BMP whenever potable water or irrigation water discharges occur at or enter a construction site. Limitations None identified. Implementation • Direct water from offsite sources around or through a construction site, where feasible, in a way that minimizes contact with the construction site. • Discharges from water line flushing should be reused for landscaping purposes where feasible. • Shut off the water source to broken lines, sprinklers, or valves as soon as possible to prevent excess water flow. • Protect downstream stormwater drainage systems and watercourses from water pumped or bailed from trenches excavated to repair water lines. Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: if Primary Objective J Secondary Objective Targeted Constituents Sediment i Nutrients i Trash Metals t Bacteria Oil and Grease Organics i Potential Alternatives None C ASQA California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 2 Vehicle and Equipment Cleaning NS-8 Description and Purpose Vehicle and equipment cleaning procedures and practices prevent or reduce the discharge of pollutants to stormwater from vehicle and equipment cleaning by using offsite facilities; washing in designated, contained areas only; eliminating discharges to the storm drain by infiltrating the wash water; and training employees and subcontractors. Suitable Applications These procedures are suitable on all construction sites where vehicle and equipment cleaning is performed. Limitations Even phosphate-free, biodegradable soaps have been shown to be toxic to fish before the soap degrades. Sending vehicles/equipment offsite should be done in conjunction with TC-i, Stabilized Construction Entrance/ Exit. Implementation Use an offsite commercial washing business as much as possible. These businesses are better equipped to handle and dispose of the wash waters properly. Performing this work offsite can also be economical by eliminating the need for a separate washing operation onsite. • Use phosphate-free, biodegradable soaps. • Educate employees and subcontractors on pollution prevention measures. Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater /• Management Control Waste Management and Materials Pollution Control Legend: v Primary Objective J Secondary Objective Targeted Constituents Sediment i Nutrients i Trash Metals Bacteria Oil and Grease i Organics * Potential Alternatives None ASQA California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbook.com lof 3 Vehicle and Equipment Cleaning NS-8 • Inspect BMPs subject to non-stormwater discharges daily while non-stormwater discharges occur. • Inspection and maintenance is minimal, although some berm repair may be necessary. • Monitor employees and subcontractors throughout the duration of the construction project to ensure appropriate practices are being implemented. • Inspect sump regularly and remove liquids and sediment as needed. • Prohibit employees and subcontractors from washing personal vehicles and equipment on the construction site. References Stormwater Quality Handbooks - Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Swisher, R.D. Surfactant Biodegradation, Marcel Decker Corporation, 1987. January 2003 California Stormwater BMP Handbook 3 of 3 Construction www.cabmphandbook.com Vehicle and Equipment Fueling NS-9 Description and Purpose Vehicle equipment fueling procedures and practices are designed to prevent fuel spills and leaks, and reduce or eliminate contamination of stormwater. This can be accomplished by using offsite facilities, fueling in designated areas only, enclosing or covering stored fuel, implementing spill controls, and training employees and subcontractors in proper fueling procedures. Suitable Applications These procedures are suitable on all construction sites where vehicle and equipment fueling takes place. Limitations Onsite vehicle and equipment fueling should only be used where it is impractical to send vehicles and equipment offsite for fueling. Sending vehicles and equipment offsite should be done in conjunction with TC-l, Stabilized Construction Entrance/ Exit. Implementation • Use offsite fueling stations as much as possible. These businesses are better equipped to handle fuel and spills properly. Performing this work offsite can also be economical by eliminating the need for a separate fueling area at a site. • Discourage "topping-off" of fuel tanks. Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stomnwater / Management Control Waste Management and Materials Pollution Control Legend: J Primary Objective / Secondary Objective Targeted Constituents Sediment Nutrients Trash Metals Bacteria Oil and Grease i Organics Potential Alternatives None CASQA Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com lof 3 Vehicle and Equipment Fueling NS-9 References Blueprint for a Clean Bay: Best Management Practices to Prevent Stormwater Pollution from Construction Related Activities; Santa Clara Valley Nonpoint Source Pollution Control Program, 1995- Coastal Nonpoint Pollution Control Program: Program Development and Approval Guidance, Working Group Working Paper; USEPA, April 1992. Stormwater Quality Handbooks - Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Stormwater Management for Construction Activities, Developing Pollution Prevention Plans and Best Management Practices, EPA 832-^92005; USEPA, April 1992. January 2003 California Stormwater BMP Handbook 3 of 3 Construction www.cabmphandbooks.com Vehicle & Equipment Maintenance NS-10 Description and Purpose Prevent or reduce the contamination of stormwater resulting from vehicle and equipment maintenance by running a "dry and clean site". The best option would be to perform maintenance activities at an offsite facility. If this option is not available then work should be performed in designated areas only, while providing cover for materials stored outside, checking for leaks and spills, and containing and cleaning up spills immediately. Employees and subcontractors must be trained in proper procedures. Suitable Applications These procedures are suitable on all construction projects where an onsite yard area is necessary for storage and maintenance of heavy equipment and vehicles. Limitations Onsite vehicle and equipment maintenance should only be used where it is impractical to send vehicles and equipment offsite for maintenance and repair. Sending vehicles/equipment offsite should be done in conjunction with TC-i, Stabilized Construction Entrance/Exit. Outdoor vehicle or equipment maintenance is a potentially significant source of stormwater pollution. Activities that can contaminate stormwater include engine repair and service, changing or replacement of fluids, and outdoor equipment storage and parking (engine fluid leaks). For further information on vehicle or equipment servicing, see NS-8, Vehicle and Equipment Cleaning, and NS-9, Vehicle and Equipment Fueling. Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: </ Primary Objective / Secondary Objective Targeted Constituents Sediment Nutrients Trash Metals Bacteria Oil and Grease Organics < Potential Alternatives None C ASQA California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 4 Vehicle & Equipment Maintenance NS-10 Listed below is further information if you must perform vehicle or equipment maintenance onsite. Safer Alternative Products m Consider products that are less toxic or hazardous than regular products. These products are often sold under an "environmentally friendly" label. • Consider use of grease substitutes for lubrication of truck fifth-wheels. Follow manufacturers label for details on specific uses. • Consider use of plastic friction plates on truck fifth-wheels in lieu of grease. Follow manufacturers label for details on specific uses. Waste Reduction Parts are often cleaned using solvents such as trichloroethylene, trichloroethane, or methylene chloride. Many of these cleaners are listed in California Toxic Rule as priority pollutants. These materials are harmful and must not contaminate stormwater. They must be disposed of as a hazardous waste. Reducing the number of solvents makes recycling easier and reduces hazardous waste management costs. Often, one solvent can perform a job as well as two different solvents. Also, if possible, eliminate or reduce the amount of hazardous materials and waste by substituting non-hazardous or less hazardous materials. For example, replace chlorinated organic solvents with non-chlorinated solvents. Non-chlorinated solvents like kerosene or mineral spirits are less toxic and less expensive to dispose of properly. Check the list of active ingredients to see whether it contains chlorinated solvents. The "chlor" term indicates that the solvent is chlorinated. Also, try substituting a wire brush for solvents to clean parts. Recycling and Disposal Separating wastes allows for easier recycling and may reduce disposal costs. Keep hazardous wastes separate, do not mix used oil solvents, and keep chlorinated solvents (like,- trichloroethane) separate from non-chlorinated solvents (like kerosene and mineral spirits). Promptly transfer used fluids to the proper waste or recycling drums. Don't leave full drip pans or other open containers lying around. Provide cover and secondary containment until these materials can be removed from the site. Oil filters can be recycled. Ask your oil supplier or recycler about recycling oil filters. Do not dispose of extra paints and coatings by dumping liquid onto the ground or throwing it into dumpsters. Allow coatings to dry or harden before disposal into covered dumpsters. Store cracked batteries in a non-leaking secondary container. Do this with all cracked batteries, even if you think all the acid has drained out. If you drop a battery, treat it as if it is cracked. Put it into the containment area until you are sure it is not leaking. Costs All of the above are low cost measures. Higher costs are incurred to setup and maintain onsite maintenance areas. January 2003 California Stormwater BMP Handbook 3 of 4 Construction www.cabmphandbooks.com Pile Driving Operations NS-11 Description and Purpose The construction and retrofit of bridges and retaining walls often include driving piles for foundation support and shoring operations. Driven piles are typically constructed of precast concrete, steel, or timber. Driven sheet piles are also used for shoring and cofferdam construction. Proper control and use of equipment, materials, and waste products from pile driving operations will reduce or eliminate the discharge of potential pollutants to the storm drain system, watercourses, and waters of the United States. Suitable Applications These procedures apply to all construction sites near or adjacent to a watercourse or groundwater where permanent and temporary pile driving (impact and vibratory) takes place, including operations using pile shells as well as construction of cast-in-steel-shell and cast-in-drilled-hole piles. Limitations None identified. Implementation • Use drip pans or absorbent pads during vehicle and equipment operation, maintenance, cleaning, fueling, and storage. Refer to NS-8, Vehicle and Equipment Cleaning, NS-9, Vehicle and Equipment Fueling, and NS-io, Vehicle and Equipment Maintenance. Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater / Management Control Waste Management and Materials Pollution Control Legend: if Primary Objective / Secondary Objective Targeted Constituents Sediment < Nutrients Trash Metals Bacteria Oil and Grease i Organics Potential Alternatives None C.XSQA California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 2 Concrete Curing NS-12 Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: S Primary Objective / Secondary Objective Description and Purpose Concrete curing is used in the construction of structures such as bridges, retaining walls, pump houses, large slabs, and structured foundations. Concrete curing includes the use of both chemical and water methods. Discharges of stormwater and non-stormwater exposed to concrete during curing may have a high pH and may contain chemicals, metals, and fines. Proper procedures reduce or eliminate the contamination of stormwater runoff during concrete curing. Suitable Applications Suitable applications include all projects where Portland Cement Concrete (PCC) and concrete curing chemicals are placed where they can be exposed to rainfall, runoff from other areas, or where runoff from the PCC will leave the site. Limitations None identified. Implementation Chemical Curing m Avoid over spray of curing compounds. • Minimize the drift of chemical cure as much as possible by applying the curing compound close to the concrete surface. Apply an amount of compound that covers the surface, but does not allow any runoff of the compound. • Use proper storage and handling techniques for concrete curing compounds. Refer to WM-i, Material Delivery and Storage. Targeted Constituents Sediment Nutrients Trash Metals Bacteria Oil and Grease Organics Potential Alternatives None California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 2 Concrete Finishing NS-13 Description and Purpose Concrete finishing methods are used for bridge deck rehabilitation, paint removal, curing compound removal, and final surface finish appearances. Methods include sand blasting, shot blasting, grinding, or high pressure water blasting. Stormwater and non-stormwater exposed to concrete finishing by-products may have a high pH and may contain chemicals, metals, and fines. Proper procedures and implementation of appropriate BMPs can minimize the impact that concrete-finishing methods may have on stormwater and non-storrnwater discharges. Suitable Applications These procedures apply to all construction locations where concrete finishing operations are performed. Limitations None identified. Implementation • Collect and properly dispose of water from high-pressure water blasting operations. • Collect contaminated water from blasting operations at the top of slopes. Transport or dispose of contaminated water while using BMPs such as those for erosion control. Refer to EC-9, Earth Dikes and Drainage Swales, EC-io, Velocity Dissipation Devices, and EC-n, Slope Drains. Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Maten'als Pollution Control Legend: J Primary Objective •/ Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals i Bacteria Oil and Grease Organics i Potential Alternatives None QA California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 2 Material Over Water NS-14 Objectives Description and Purpose Procedures for the proper use, storage, and disposal of materials and equipment on barges, boats, temporary construction pads, or similar locations, that minimize or eliminate the discharge of potential pollutants to a watercourse. Suitable Applications Applies where materials and equipment are used on barges, boats, docks, and other platforms over or adjacent to a watercourse including waters of the United States. These procedures should be implemented for construction materials and wastes (solid and liquid), soil or dredging materials, or any other materials that may cause-or contribute to exceedances of water quality standards. Limitations Dredge and fill activities are regulated by the US Army Corps of Engineers and Regional Boards under Section 404/401 of the Clean Water Act. Implementation • Refer to WM-i, Material Delivery and Storage and WM-4, Spill Prevention and Control. • Use drip pans and absorbent materials for equipment and vehicles and ensure that an adequate supply of spill clean up materials is available. • Drip pans should be placed under all vehicles and equipment placed on docks, barges, or other structures over water bodies EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: V Primary Objective / Secondary Objective Targeted Constituents Sediment Nutrients Trash Metals Bacteria Oil and Grease * Organics * Potential Alternatives None AIQ A California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 3 Material Over Water NS-14 Stormwater Management for Construction Activities, Developing Pollution Prevention Plans and Best Management Practices, EPA 832-^92005; USEPA, April 1992. January 2003 California Stormwater BMP Handbook 3 of 3 Construction www.cabmphandbooks.com Demolition Adjacent to Water NS-15 Description and Purpose Procedures to protect water bodies from debris and wastes associated with structure demolition or removal over or adjacent to watercourses. Suitable Applications Full bridge demolition and removal, partial bridge removal (barrier rail, edge of deck) associated with bridge widening projects, concrete channel removal, or any other structure removal that could potentially affect water quality. Limitations None identified. Implementation • Refer to NS-5, Clear Water Diversion, to direct water away from work areas. • Use attachments on construction equipment such as backhoes to catch debris from small demolition operations. • Use covers or platforms to collect debris. • Platforms and covers are to be approved by the owner. • Stockpile accumulated debris and waste generated during demolition away from watercourses and in accordance with WM-3, Stockpile Management. • Ensure safe passage of wildlife, as necessary. Objectives EC Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: S Primary Objective / Secondary Objective SE TC WE NS WM Targeted Constituents Sediment J Nutrients J Trash S Metals </ Bacteria S Oil and Grease J Organics J Potential Alternatives None __AS.0A ( f California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 2 NS-15 Demolition Adjacent to Water • Discharges to waterways shall be reported to the Regional Water Quality Control Board immediately upon discovery. A written discharge notification must follow within 7 days. Follow the spill reporting procedures in the SWPPP. • For structures containing hazardous materials, i.e., lead paint or asbestos, refer to BMP WM-6, Hazardous Waste Management. For demolition work involving soil excavation around lead-painted structures, refer to WM-y, Contaminated Soil Management. Costs Cost may vary according to the combination of practices implemented. Inspection and Maintenance • Inspect and verify that activity-based BMPs are in place prior to the commencement of associated activities. While activities associated with the BMP are under way, inspect weekly during the rainy season and of two-week intervals in the non-rainy season to verify continued BMP implementation. • Inspect BMPs subject to non-stormwater discharge daily while non-stormwater discharges occur. • Any debris-catching devices shall be emptied regularly. Collected debris shall be removed and stored away from the watercourse and protected from runon and runoff. References Stormwater Quality Handbooks - Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Stormwater Management for Construction Activities, Developing Pollution Prevention Plans and Best Management Practices, EPA 832-^92005; USEPA, April 1992. 2 Of 2 California Stormwater BMP Handbook Construction www.cabmphandbooks.com January 2003 Temporary Batch Plants NS-16 Description and Purpose The construction of roads, bridges, retaining walls, and other large structures in remote areas, often requires temporary batch plant facilities to manufacture Portland Cement Concrete (PCC) or asphalt cement (AC). Temporary batch plant facilities typically consist of silos containing fly ash, lime, and cement; heated tanks of liquid asphalt; sand and gravel material storage areas; mixing equipment; above ground storage tanks containing concrete additives and water; and designated areas for sand and gravel truck unloading, concrete truck loading, and concrete truck washout. Proper control and use of equipment, materials, and waste products from temporary batch plant facilities will reduce the discharge of potential pollutants to the storm drain system or watercourses, reduce air emissions, and mitigate noise impacts. Suitable Applications These procedures typically apply to construction sites where temporary batch plant facilities are used. Limitations The General Permit for discharges of stormwater associated with industrial activities may be applicable to temporary batch plants. Specific permit requirements or mitigation measures such as Air Resources Board (ARE), Air Quality Management District (AQMD), Air Pollution Control District (APCD), Regional Water Quality Control Board (RWQCB), county ordinances and city Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater /• Management Control Waste Management and Materials Pollution Control Legend: */ Primary Objective / Secondary Objective Targeted Constituents Sediment Nutrients Trash Metals < Bacteria Oil and Grease Organics Potential Alternatives None California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 6 NS-16 Temporary Batch Plants ordinances may require alternative mitigation measures for temporary batch plants. Implementation Planning Implementation steps are as follows: • Temporary batch plants may be subject to the General Industrial NPDES permit. To comply with the permit, a Notice of Intent (NOI) must be submitted to the State Water Resource Control Board. • Proper planning, design, and construction of temporary batch plants should be implemented to minimize potential water quality, air pollution, and noise impacts associated with temporary batch plants. • BMPs and a Sampling and Analysis Plan (SAP) must be included in the project Stormwater Pollution Prevention Plan (SWPPP). BMPs must be implemented, inspected, and maintained. • Temporary batch plants should be managed to comply with AQMD Statewide Registration Program and/or local AQMD Portable Equipment Registration requirements. • Construct temporary batch plants down-wind of existing developments whenever possible. • Placement of access roads should be planned to mitigate water and air quality impacts. Layout and Design m Temporary batch plants should be properly located and designed to mitigate water quality impacts to receiving water bodies. Batch plants should be located away from watercourses, drainage courses, and drain inlets. Batch plants should be located to minimize the potential for stormwater runon onto the site. • Temporary batch plant facilities (including associated stationary equipment and stockpiles) should be located at least 300 ft from any recreational area, school, residence, or other structure not associated with the construction project. • Construct continuous interior AC or PCC berms around batch plant equipment (mixing equipment, silos, concrete drop points, conveyor belts, admixture tanks, etc.) to facilitate proper containment and cleanup of releases. Rollover or flip top curb or dikes should be placed at ingress and egress points. • Direct runoff from the paved or unpaved portion of the batch plant into a sump and pipe to a lined washout area or dewatering tank. • Direct stormwater and non-stormwater runoff from unpaved portions of batch plant facility to catchment ponds or tanks. • Construct and remove concrete washout facilities in accordance with WM-8, Concrete Waste Management. 2 of 6 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Temporary Batch Plants NS-16 • Layout of a typical batch plant and associated BMP is located at the end of this BMP fact sheet. Operational Procedures • Washout of concrete trucks should be conducted in a designated area in accordance with WM-8, Concrete Waste Management. • Do not dispose of concrete into drain inlets, the stormwater drainage system, or watercourses. • Equipment washing should occur in a designated area in accordance with WM-8, Concrete Waste Management. Washing equipment, tools, or vehicles to remove PCC shall be conducted in accordance with NS-y, Potable Water/Irrigation, and NS-8, Vehicle and Equipment Cleaning. • All dry material transfer points should be ducted through a fabric or cartridge type filter unless there are no visible emissions from the transfer point. • Equip all bulk storage silos, including auxiliary bulk storage trailers, with fabric or cartridge type filter(s). • Maintain silo vent filters in proper operating condition. • Equip silos and auxiliary bulk storage trailers with dust-tight service hatches. • Fabric dust collection system should be capable of controlling 99 percent of the particulate matter. • Fabric dust collectors (except for vent filters) should be equipped with an operational pressure differential gauge to measure the pressure drop across the filters. • All transfer points should be equipped with a wet suppression system to control fugitive particulate emissions unless there are no visible emissions. • All conveyors should be covered, unless the material being transferred results in no visible emissions. • There should be no visible emissions beyond the property line, while the equipment is being operated. • Collect dust emissions from the loading of open-bodied trucks at the drip point of dry batch plants, or dust emissions from the drum feed for central mix plants. • Equip silos and auxiliary bulk storage trailers with a visible and/or audible warning mechanism to warn operators that the silo or trailer is full. • All open-bodied vehicles transporting material should be loaded with a final layer of wet sand and the truck shall be covered with a tarp to reduce emissions. January 2003 California Stormwater BMP Handbook 3 of 6 Construction www.cabmphandbooks.com NS-16 Temporary Batch Plants Tracking Control • Plant roads (batch truck and material delivery truck roads) and areas between stockpiles and conveyor hoppers should be stabilized (TC-2, Stabilized Construction Roadway), watered (WE-i, Wind Erosion Control), treated with dust-suppressant chemicals, or paved with a cohesive hard surface that can be repeatedly swept, maintained intact, and cleaned as necessary to control dust emissions. • Trucks should not track PCC from plants onto onto public roads. Use appropriate practices from TC-i, Stabilized Construction Entrance/Exit to prevent tracking. Materials Storage m WM-i, Material Delivery and Storage, should be implemented at all batch plants using concrete components or compounds. An effective strategy is to cover and contain materials. • WM-2, Material Use should be conducted in a way to minimize or eliminate the discharge of materials to storm drain system or watercourse. • Ensure that finer materials are not dispersed into the air during operations, such as unloading of cement delivery trucks. • Stockpiles should be covered and enclosed with perimeter sediment barriers per WM-3, Stockpile Management. Uncovered stockpiles should be sprinkled with water and/or dust- suppressant chemicals as necessary to control dust emissions, unless the stockpiled material results in no visible emissions. An operable stockpile watering system should be onsite at all times. • Store bagged and boxed materials on pallets and cover on non-working days prior to rain. • Minimize stockpiles of demolished PCC by recycling them in a timely manner. • Provide secondary containment for liquid materials (WM-i). Containment should provide sufficient volume to contain precipitation from a 25-year storm plus 10% of the aggregate volume of all containers or plus 100% of the largest container, whichever is greater. • Handle solid and liquid waste in accordance with WM-5, Solid Waste Management, WM-io, Liquid Waste Management, and WM-8, Concrete Waste Management. • Maintain adequate supplies of spill cleanup materials and train staff to respond to spills per WM-4, Spill Prevention and Control. • Immediately clean up spilled cement and fly ash and contain or dampen so that dust or emissions from wind erosion or vehicle traffic are minimized. Equipment Maintenance m Equipment should be maintained to prevent fluid leaks and spills per NS-9, Vehicle and Equipment Fueling, and NS-1O, Vehicle and Equipment Maintenance. • Maintain adequate supplies of spill cleanup materials and train staff to respond to spills per WM-4, Spill Prevention and Control. 4 of 6 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Temporary Batch Plants NS-16 • Incorporate other BMPs such as WM-5, Solid Waste Management, WM-6, Hazardous Waste Management, and WM-io, Liquid Waste Management. Costs Costs will vary depending on the size of the facility and combination of BMPs implemented. Inspection and Maintenance • Inspect and verify that activity-based BMPs are in place prior to the commencement of associated activities. While activities associated with the BMP are under way, inspect weekly during the rainy season and of two-week intervals in the non-rainy season to verify continued BMP implementation. • Inspect BMPs subject to non-stormwater discharge daily while non-stormwater discharges occur. • Inspect and repair equipment (for damaged hoses, fittings, and gaskets). • Inspect and maintain Stabilized Construction Entrance/Exit (TC-i) as needed. • Inspect and maintain stabilized haul roads as needed. • Inspect and maintain materials and waste storage areas as needed. References Stormwater Quality Handbooks - Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Stormwater Management for Construction Activities, Developing Pollution Prevention Plans and Best Management Practices, EPA 832-^92005; USEPA, April 1992. January 2003 California Stormwater BMP Handbook 5 of 6 Construction www.cabmphandbooks.com NS-16 Temporary Batch Plants inU CONTROL IQUIPMINT (WM-4)EQUIPMENT WASHINO (WM-8) CONCRiTI TRUCK WASHOUT ARIA (WM-8) MIXINO PLANT (WM.1, WM.2)eoNCRiri TRUCK LOADING ARIA ITARILIZID INTRANCE/BXIT/- (Tc-n jp ITARILIZIDENTRANCE/<re.n MATERIAL UNLOADIN9/ITORAOI N9TllAOMTIONM. IMP* MW H APHICMUrM«MNIW<IN«OR-THIWUUWNTWIC * OIRICT DRAINAOI OP UNPAVID ARIAS m TO CATCHMINT POND POR DIWATIRINO IN ACCORDANCI WITH NS.J o Typical Temporary Batch 6 of 6 California Stormwater BMP Handbook Construction www.cabmphandbooks.com January 2003 Material Delivery and Storage WM-1 Description and Purpose Prevent, reduce, or eliminate the discharge of pollutants from material delivery and storage to the stormwater system or watercourses by minimizing the storage of hazardous materials onsite, storing materials in a designated area, installing secondary containment, conducting regular inspections, and training employees and subcontractors. This best management practice covers only material delivery and storage. For other information on materials, see WM-2, Material Use, or WM-4, Spill Prevention and Control. For information on wastes, see the waste management BMPs in this section. Suitable Applications These procedures are suitable for use at all construction sites with delivery and storage of the following materials: • Soil stabilizers and binders • Pesticides and herbicides • Fertilizers • Detergents • Plaster • Petroleum products such as fuel, oil, and grease • Asphalt and concrete components Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: v Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients i Trash i Metals i Bacteria Oil and Grease i Organics i Potential Alternatives None ss$Mt stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 5 WM-1 _ Material Delivery and Storage / ' /"Us• Hazardous chemicals such as acids, lime, glues, adhesives, paints, solvents, and curing I ,j compounds • Concrete compounds • Other materials that may be detrimental if released to the environment Limitations • Space limitation may preclude indoor storage. • Storage sheds often must meet building and fire code requirements. Implementation The following steps should be taken to minimize risk: • Temporary storage area should be located away from vehicular traffic. • Material Safety Data Sheets (MSDS) should be supplied for all materials stored. • Construction site areas should be designated for material delivery and storage. • Material delivery and storage areas should be located near the construction entrances, away from waterways, if possible. - Avoid transport near drainage paths or waterways. ^n, ( w Surround with earth berms. See EC-9, Earth Dikes and Drainage Swales. Place in an area which will be paved. • Storage of reactive, ignitable, or flammable liquids must comply with the fire codes of your area. Contact the local Fire Marshal to review site materials, quantities, and proposed storage area to determine specific requirements. See the Flammable and Combustible Liquid Code, NFPAao. • An up to date inventory of materials delivered and stored onsite should be kept. • Hazardous materials storage onsite should be minimized. • Hazardous materials should be handled as infrequently as possible. • During the rainy season, consider storing materials in a covered area. Store materials in secondary containments such as earthen dike, horse trough, or even a children's wading pool for non-reactive materials such as detergents, oil, grease, and paints. Small amounts of material may be secondarily contained in "bus boy" trays or concrete mixing trays. • Do not store chemicals, drums, or bagged materials directly on the ground. Place these items on a pallet and, when possible, in secondaiy containment. 2 of 5 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Material Delivery and Storage WM-1 • If drums must be kept uncovered, store them at a slight angle to reduce ponding of rainwater on the lids to reduce corrosion. Domed plastic covers are inexpensive and snap to the top of drums, preventing water from collecting. • Chemicals should be kept in their original labeled containers. • Employees and subcontractors should be trained on the proper material delivery and storage practices. • Employees trained in emergency spill cleanup procedures must be present when dangerous materials or liquid chemicals are unloaded. • If significant residual materials remain on the ground after construction is complete, properly remove materials and any contaminated soil. See WM-7, Contaminated Soil Management. If the area is to be paved, pave as soon as materials are removed to stabilize the soil. Material Storage Areas and Practices m Liquids, petroleum products, and substances listed in 40 CFR Parts no, 117, or 302 should be stored in approved containers and drums and should not be overfilled. Containers and drums should be placed in temporary containment facilities for storage. • A temporary containment facility should provide for a spill containment volume able to contain precipitation from a 25 year storm event, plus the greater of 10% of the aggregate volume of all containers or 100% of the capacity of the largest container within its boundary, whichever is greater. • A temporary containment facility should be impervious to the materials stored therein for a minimum contact time of 72 hours. • A temporary containment facility should be maintained free of accumulated rainwater and spills. In the event of spills or leaks, accumulated rainwater and spills should be collected and placed into drums. These liquids should be handled as a hazardous waste unless testing determines them to be non-hazardous. All collected liquids or non-hazardous liquids should be sent to an approved disposal site. • Sufficient separation should be provided between stored containers to allow for spill cleanup and emergency response access. • Incompatible materials, such as chlorine and ammonia, should not be stored in the same temporary containment facility. • Throughout the rainy season, each temporary containment facility should be covered during non-working days, prior to, and during rain events. • Materials should be stored in their original containers and the original product labels should be maintained in place in a legible condition. Damaged or otherwise illegible labels should be replaced immediately. January 2003 California Stormwater BMP Handbook 3 of 5 Construction www.cabmphandbooks.com WM-1 _ Material Delivery and Storage m Bagged and boxed materials should be stored on pallets and should not be allowed to accumulate on the ground. To provide protection from wind and rain throughout the rainy season, bagged and boxed materials should be covered during non-working days and prior to and during rain events. • Stockpiles should be protected in accordance with WM-3, Stockpile Management. • Materials should be stored indoors within existing structures or sheds when available. • Proper storage instructions should be posted at all times in an open and conspicuous location. • An ample supply of appropriate spill clean up material should be kept near storage areas. • Also see WM-6, Hazardous Waste Management, for storing of hazardous materials. Material Delivery Practices • Keep an accurate, up-to-date inventory of material delivered and stored onsite. • Arrange for employees trained in emergency spill cleanup procedures to be present when dangerous materials or liquid chemicals are unloaded. Spill Cleanup m Contain and clean up any spill immediately. • Properly remove and dispose of any hazardous materials or contaminated soil if significant residual materials remain on the ground after construction is complete. See WM-y, Contaminated Soil Management. • See WM-4, Spill Prevention and Control, for spills of chemicals and/or hazardous materials. Cost • The largest cost of implementation may be in the construction of a materials storage area that is covered and provides secondary containment. Inspection and Maintenance • Inspect and verify that activity-based BMPs are in place prior to the commencement of associated activities. While activities associated with the BMP are under way, inspect weekly during the rainy season and of two-week intervals in the non-rainy season to verify continued BMP implementation. • Keep an ample supply of spill cleanup materials near the storage area. • Keep storage areas clean, well organized, and equipped with ample cleanup supplies as appropriate for the materials being stored. • Repair or replace perimeter controls, containment structures, covers, and liners as needed to maintain proper function. 4 of 5 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Material Delivery and Storage WM-1 References Blueprint for a Clean Bay: Best Management Practices to Prevent Stormwater Pollution from Construction Related Activities; Santa Clara Valley Nonpoint Source Pollution Control Program, 1995- Coastal Nonpoint Pollution Control Program: Program Development and Approval Guidance, Working Group Working Paper; USEPA, April 1992. Stormwater Quality Handbooks - Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Stormwater Management for Construction Activities; Developing Pollution Prevention Plans and Best Management Practice, EPA 832-^92005; USEPA, April 1992. January 2003 California Stormwater BMP Handbook 5 of 5 Construction www.cabmphandbooks.com Material Use WM-2 Objectives Description and Purpose Prevent or reduce the discharge of pollutants to the storm drain system or watercourses from material use by using alternative products, minimizing hazardous material use onsite, and training employees and subcontractors. Suitable Applications This BMP is suitable for use at all construction projects. These procedures apply when the following materials are used or prepared onsite: • Pesticides and herbicides • Fertilizers • Detergents • Plaster • Petroleum products such as fuel, oil, and grease • Asphalt and other concrete components • Other hazardous chemicals such as acids, lime, glues, adhesives, paints, solvents, and curing compounds • Concrete compounds • Other materials that may be detrimental if released to the environment EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and /• Materials Pollution Control Legend: ir Primary Objective / Secondary Objective Targeted Constituents Sediment < Nutrients i Trash i Metals i Bacteria Oil and Grease i Organics < Potential Alternatives None ASQA California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 3 WM-2 Material Use Limitations Safer alternative building and construction products may not be available or suitable in every instance. Implementation The following steps should be taken to minimize risk: • Minimize use of hazardous materials onsite. • Follow manufacturer instructions regarding uses, protective equipment, ventilation, flammability, and mixing of chemicals. • Train personnel who use pesticides. The California Department of Pesticide Regulation and county agricultural commissioners license pesticide dealers, certify pesticide applicators, and conduct onsite inspections. • Do not over-apply fertilizers, herbicides, and pesticides. Prepare only the amount needed. Follow the recommended usage instructions. Over-application is expensive and environmentally harmful. Unless on steep slopes, till fertilizers into the soil rather than hydro seeding. Apply surface dressings in several smaller applications, as opposed to one large application, to allow time for infiltration and to avoid excess material being carried offsite by runoff. Do not apply these chemicals just before it rains. • Train employees and subcontractors in proper material use. • Supply Material Safety Data Sheets (MSDS) for all materials. • Dispose of latex paint and paint cans, used brushes, rags, absorbent materials, and drop cloths, when thoroughly dry and are no longer hazardous, with other construction debris. • Do not remove the original product label; it contains important safety and disposal information. Use the entire product before disposing of the container. • Mix paint indoors or in a containment area. Never clean paintbrushes or rinse paint containers into a street, gutter, storm drain, or watercourse. Dispose of any paint thinners, residue, and sludge(s) that cannot be recycled, as hazardous waste. • For water-based paint, clean brushes to the extent practicable, and rinse to a drain leading to a sanitary sewer where permitted, or into a concrete washout pit or temporary sediment trap. For oil-based paints, clean brushes to the extent practicable, and filter and reuse thinners and solvents. • Use recycled and less hazardous products when practical. Recycle residual paints, solvents, non-treated lumber, and other materials. • Use materials only where and when needed to complete the construction activity. Use safer alternative materials as much as possible. Reduce or eliminate use of hazardous materials onsite when practical. 2 of 3 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Material Use WM-2 • Require contractors to complete the "Report of Chemical Spray Forms" when spraying herbicides and pesticides. • Keep an ample supply of spill clean up material near use areas. Train employees in spill clean up procedures. • Avoid exposing applied materials to rainfall and runoff unless sufficient time has been allowed for them to dry. Costs All of the above are low cost measures. Inspection and Maintenance • Inspect and verify that activity-based BMPs are in place prior to the commencement of associated activities. While activities associated with the BMP are under way, inspect weekly during the rainy season and at two-week intervals in the non-rainy season to verify continued BMP implementation. • Maintenance of this best management practice is minimal. • Spot check employees and subcontractors throughout the job to ensure appropriate practices are being employed. References Blueprint for a Clean Bay: Best Management Practices to Prevent Stormwater Pollution from Construction Related Activities; Santa Clara Valley Nonpoint Source Pollution Control Program, 1995- Coastal Nonpoint Pollution Control Program: Program Development and Approval Guidance, Working Group Working Paper; USEPA, April 1992. Stormwater Quality Handbooks - Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Stormwater Management for Construction Activities; Developing Pollution Prevention Plans and Best Management Practice, EPA 832^-92005; USEPA, April 1992. January 2003 California Stormwater BMP Handbook 3 of 3 Construction www.cabmphandbooks.com Stockpile Management WM-3 Description and Purpose Stockpile Management procedures and practices are designed to reduce or eliminate air and stormwater pollution from stockpiles of-soil, paving materials such as portland cement concrete (PCC) rubble, asphalt concrete (AC), asphalt concrete rubble, aggregate base, aggregate sub base or pre-mixed aggregate, asphalt minder (so called "cold mix" asphalt), and pressure treated wood. Suitable Applications Implement in all projects that stockpile soil and other materials. Limitations None identified. Implementation Protection of stockpiles is a year-round requirement. To properly manage stockpiles: a Locate stockpiles a minimum of 50 ft away from concentrated flows of stormwater, drainage courses, and inlets. • Protect all stockpiles from stormwater runon using a temporary perimeter sediment barrier such as berms, dikes, fiber rolls, silt fences, sandbag, gravel bags, or straw bale barriers. Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and / Materials Pollution Control Legend: J Primary Objective J Secondary Objective Targeted Constituents Sediment i Nutrients i Trash i Metals i Bacteria Oil and Grease ^ Organics i Potential Alternatives None CASQA California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 3 WM-3 Stockpile Management • Implement wind erosion control practices as appropriate on all stockpiled material. For ( specific information, see WE-l, Wind Erosion Control. • Manage stockpiles of contaminated soil in accordance with WM-y, Contaminated Soil Management. • Place bagged materials on pallets and under cover. Protection of Non-Active Stockpiles Non-active stockpiles of the identified materials should be protected further as follows: Soil stockpiles m During the rainy season, soil stockpiles should be covered or protected with soil stabilization measures and a temporary perimeter sediment barrier at all times. • During the non-rainy season, soil stockpiles should be covered or protected with a temporary perimeter sediment barrier prior to the onset of precipitation. Stockpiles of Portland cement concrete rubble, asphalt concrete, asphalt concrete rubble, aggregate base, or aggregate sub base m During the rainy season, the stockpiles should be covered or protected with a temporary perimeter sediment barrier at all times. • During the non-rainy season, the stockpiles should be covered or protected with a temporary perimeter sediment barrier prior to the onset of precipitation. ( 1 Stockpiles of "cold mix" • During the rainy season, cold mix stockpiles should be placed on and covered with plastic or comparable material at all times. • During the non-rainy season, cold mix stockpiles should be placed on and covered with plastic or comparable material prior to the onset of precipitation. Stockpiles/Storage of pressure treated wood with copper, chromium, and arsenic or ammonical, copper, zinc, and arsenate m During the rainy season, treated wood should be covered with plastic or comparable material at all times. • During the non-rainy season, treated wood should be covered with plastic or comparable material at all times and cold mix stockpiles should be placed on and covered with plastic or comparable material prior to the onset of precipitation. Protection of Active Stockpiles Active stockpiles of the identified materials should be protected further as follows: • All stockpiles should be protected with a temporary linear sediment barrier prior to the onset of precipitation. • Stockpiles of "cold mix" should be placed on and covered with plastic or comparable material prior to the onset of precipitation. 2 of 3 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Stockpile Management WM-3 Costs All of the above are low cost measures. Inspection and Maintenance • Inspect and verify that activity-based BMPs are in place prior to the commencement of associated activities. While activities associated with the BMP are under way, inspect weekly during the rainy season and of two-week intervals in the non-rainy season to verify continued BMP implementation • Repair and/or replace perimeter controls and covers as needed to keep them functioning properly. References Stormwater Quality Handbooks - Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. January 2003 California Stormwater BMP Handbook 3 of 3 Construction www.cabmphandbooks.com Spill Prevention and Control WM-4 £/_ Description and Purpose Prevent or reduce the discharge of pollutants to drainage systems or watercourses from leaks and spills by reducing the chance for spills, stopping the source of spills, containing and cleaning up spills, properly disposing of spill materials, and training employees. This best management practice covers only spill prevention and control. However, WM-i, Materials Delivery and Storage, and WM-2, Material Use, also contain useful information, particularly on spill prevention. For information on wastes, see the waste management BMPs in this section. Suitable Applications This BMP is suitable for all construction projects. Spill control procedures are implemented anytime chemicals or hazardous substances are stored on the construction site, including the following materials: • Soil stabilizers/binders • Dust palliatives • Herbicides • Growth inhibitors • Fertilizers • Deicing/anti-icing chemicals Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and /• Materials Pollution Control Legend: V Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients 1 Trash i Metals i Bacten'a Oil and Grease i Organics i Potential Alternatives None SQA California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 6 Spill Prevention and Control WM-4 • Fuels ( ^ • Lubricants • Other petroleum distillates Limitations • In some cases it may be necessary to use a private spill cleanup company. • This BMP applies to spills caused by the contractor and subcontractors. • Procedures and practices presented in this BMP are general. Contractor should identify appropriate practices for the specific materials used or stored onsite Implementation The following steps will help reduce the stormwater impacts of leaks and spills: Education • Be aware that different materials pollute in different amounts. Make sure that each employee knows what a "significant spill" is for each material they use, and what is the appropriate response for "significant" and "insignificant" spills. • Educate employees and subcontractors on potential dangers to humans and the environment from spills and leaks. ^_ ( . , • Hold regular meetings to discuss and reinforce appropriate disposal procedures (incorporate '**** into regular safety meetings). • Establish a continuing education program to indoctrinate new employees. » Have contractor's superintendent or representative oversee and enforce proper spill prevention and control measures. General Measures m To the extent that the work can be accomplished safely, spills of oil, petroleum products, substances listed under 40 CFR parts 110,117, and 302, and sanitary and septic wastes should be contained and cleaned up immediately. • Store hazardous materials and wastes in covered containers and protect from vandalism. • Place a stockpile of spill cleanup materials where it will be readily accessible. • Train employees in spill prevention and cleanup. • Designate responsible individuals to oversee and enforce control measures. a Spills should be covered and protected from stormwater runon during rainfall to the extent that it doesn't compromise clean up activities. • Do not bury or wash spills with water. 2 of 6 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Spill Prevention and Control WM-4 • Store and dispose of used clean up materials, contaminated materials, and recovered spill material that is no longer suitable for the intended purpose in conformance with the provisions in applicable BMPs. • Do not allow water used for cleaning and decontamination to enter storm drains or watercourses. Collect and dispose of contaminated water in accordance with WM-io, Liquid Waste Management. • Contain water overflow or minor water spillage and do not allow it to discharge into drainage facilities or watercourses. • Place proper storage, cleanup, and spill reporting instructions for hazardous materials stored or used on the project site in an open, conspicuous, and accessible location. • Keep waste storage areas clean, well organized, and equipped with ample cleanup supplies as appropriate for the materials being stored. Perimeter controls, containment structures, covers, and liners should be repaired or replaced as needed to maintain proper function. Cleanup m Clean up leaks and spills immediately. • Use a rag for small spills on paved surfaces, a damp mop for general cleanup, and absorbent material for larger spills. If the spilled material is hazardous, then the used cleanup materials are also hazardous and must be sent to either a certified laundry (rags) or disposed of as hazardous waste. • Never hose down or bury dry material spills. Clean up as much of the material as possible and dispose of properly. See the waste management BMPs in this section for specific information. Minor Spills • Minor spills typically involve small quantities of oil, gasoline, paint, etc. which can be controlled by the first responder at the discovery of the spill. • Use absorbent materials on small spills rather than hosing down or burying the spill. • Absorbent materials should be promptly removed and disposed of properly. • Follow the practice below for a minor spill: Contain the spread of the spill. Recover spilled materials. Clean the contaminated area and properly dispose of contaminated materials. Semi-Significant Spills m Semi-significant spills still can be controlled by the first responder along with the aid of other personnel such as laborers and the foreman, etc. This response may require the cessation of all other activities. January 2003 California Stormwater BMP Handbook 3 of 6 Construction www.cabmphandbooks.com Spill Prevention and Control WM-4 • Spills should be cleaned up immediately: Contain spread of the spill. - Notify the project foreman immediately. If the spill occurs on paved or impermeable surfaces, clean up using "dry" methods (absorbent materials, cat litter and/or rags). Contain the spill by encircling with absorbent materials and do not let the spill spread widely. - If the spill occurs in dirt areas, immediately contain the spill by constructing an earthen dike. Dig up and properly dispose of contaminated soil. If the spill occurs during rain, cover spill with tarps or other material to prevent contaminating runoff. Significant/Hazardous Spills m For significant or hazardous spills that cannot be controlled by personnel in the immediate vicinity, the following steps should be taken: - Notify the local emergency response by dialing 911. In addition to 911, the contractor will notify the proper county officials. It is the contractor's responsibility to have all emergency phone numbers at the construction site. - Notify the Governor's Office of Emergency Services Warning Center, (916) 845-8911. For spills of federal reportable quantities, in conformance with the requirements in 40 CFR parts 110,119, and 302, the contractor should notify the National Response Center at (800) 424-8802. Notification should first be made by telephone and followed up with a written report. The services of a spills contractor or a Haz-Mat team should be obtained immediately. Construction personnel should not attempt to clean up until the appropriate and qualified staffs have arrived at the job site. Other agencies which may need to be consulted include, but are not limited to, the Fire Department, the Public Works Department, the Coast Guard, the Highway Patrol, the City/County Police Department, Department of Toxic Substances, California Division of Oil and Gas, Cal/OSHA, etc. Reporting a Report significant spills to local agencies, such as the Fire Department; they can assist in cleanup. • Federal regulations require that any significant oil spill into a water body or onto an adjoining shoreline be reported to the National Response Center (NRC) at 800-424-8802 (24 hours). Use the following measures related to specific activities: 4 of 6 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com SpiH Prevention and Control WM-4 Vehicle and Equipment Maintenance m If maintenance must occur onsite, use a designated area and a secondary containment, located away from drainage courses, to prevent the runon of stormwater and the runoff of spills. • Regularly inspect onsite vehicles and equipment for leaks and repair immediately • Check incoming vehicles and equipment (including delivery trucks, and employee and subcontractor vehicles) for leaking oil and fluids. Do not allow leaking vehicles or equipment onsite. • Always use secondary containment, such as a drain pan or drop cloth, to catch spills or leaks when removing or changing fluids. • Place drip pans or absorbent materials under paving equipment when not in use. • Use absorbent materials on small spills rather than hosing down or burying the spill. Remove the absorbent materials promptly and dispose of properly. • Promptly transfer used fluids to the proper waste or recycling drums. Don't leave full drip pans or other open containers lying around • Oil filters disposed of in trashcans or dumpsters can leak oil and pollute stormwater. Place the oil filter in a funnel over a waste oil-recycling drum to drain excess oil before disposal. Oil filters can also be recycled. Ask the oil supplier or recycler about recycling oil filters. • Store cracked batteries in a non-leaking secondary container. Do this with all cracked batteries even if you think all the acid has drained out. If you drop a battery, treat it as if it is cracked. Put it into the containment area until you are sure it is not leaking. Vehicle and Equipment Fueling m If fueling must occur onsite, use designate areas, located away from drainage courses, to prevent the runon of stormwater and the runoff of spills. • Discourage "topping off' of fuel tanks. • Always use secondary containment, such as a drain pan, when fueling to catch spills/ leaks. Costs Prevention of leaks and spills is inexpensive. Treatment and/ or disposal of contaminated soil or water can be quite expensive. Inspection and Maintenance • Inspect and verify that activity-based BMPs are in place prior to the commencement of associated activities. While activities associated with the BMP are under way, inspect weekly during the rainy season and of two-week intervals in the non-rainy season to verify continued BMP implementation. • Inspect BMPs subject to non-stormwater discharge daily while non-stormwater discharges occur. January 2003 California Stormwater BMP Handbook 5 of 6 Construction www.cabmphandbooks.com Spill Prevention and Control WM-4 • Keep ample supplies of spill control and cleanup materials onsite, near storage, unloading, ~**jt and maintenance areas. • Update your spill prevention and control plan and stock cleanup materials as changes occur in the types of chemicals onsite. References Blueprint for a Clean Bay: Best Management Practices to Prevent Stormwater Pollution from Construction Related Activities; Santa Clara Valley Nonpoint Source Pollution Control Program, 1995- Stormwater Quality Handbooks - Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Stormwater Management for Construction Activities; Developing Pollution Prevention Plans and Best Management Practice, EPA 832^-92005; USEPA, April 1992. 6 of 6 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Solid Waste Management WM-5 Description and Purpose Solid waste management procedures and practices are designed to prevent or reduce the discharge of pollutants to stormwater from solid or construction waste by providing designated waste collection areas and containers, arranging for regular disposal, and training employees and subcontractors. Suitable Applications This BMP is suitable for construction sites where the following wastes are generated or stored: • Solid waste generated from trees and shrubs removed during land clearing, demolition of existing structures (rubble), and building construction • Packaging materials including wood, paper, and plastic • Scrap or surplus building materials including scrap metals, rubber, plastic, glass pieces and masonry products • Domestic wastes including food containers such as beverage cans, coffee cups, paper bags, plastic wrappers, and cigarettes • Construction wastes including brick, mortar, timber, steel and metal scraps, pipe and electrical cuttings, non- hazardous equipment parts, styrofoam and other materials used to transport and package construction materials Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: •</ Primary Objective •/ Secondary Objective Targeted Constituents Sediment J Nutrients J Trash / Metals y Bacteria Oil and Grease •/ Organics S Potential Alternatives None CASO..A {California"" Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 4 WM-5 Solid Waste Management m Highway planting wastes, including vegetative material, plant containers, and packaging materials Limitations Temporary stockpiling of certain construction wastes may not necessitate stringent drainage related controls during the non-rainy season or in desert areas with low rainfall. Implementation The following steps will help keep a clean site and reduce stormwater pollution: • Select designated waste collection areas onsite. • Inform trash-hauling contractors that you will accept only watertight dumpsters for onsite use. Inspect dumpsters for leaks and repair any dumpster that is not watertight. • Locate containers in a covered area or in a secondary containment. • Provide an adequate number of containers with lids or covers that can be placed over the container to keep rain out or to prevent loss of wastes when it is windy. • Plan for additional containers and more frequent pickup during the demolition phase of construction. • Collect site trash daily, especially during rainy and windy conditions. • Remove this solid waste promptly since erosion and sediment control devices tend to collect litter. • Make sure that toxic liquid wastes (used oils, solvents, and paints) and chemicals (acids, pesticides, additives, curing compounds) are not disposed of in dumpsters designated for construction debris. • Do not hose out dumpsters on the construction site. Leave dumpster cleaning to the trash hauling contractor. • Arrange for regular waste collection before containers overflow. • Clean up immediately if a container does spill. • Make sure that construction waste is collected, removed, and disposed of only at authorized disposal areas. Education • Have the contractor's superintendent or representative oversee and enforce proper solid waste management procedures and practices. • Instruct employees and subcontractors on identification of solid waste and hazardous waste. • Educate employees and subcontractors on solid waste storage and disposal procedures. 2 of 4 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Solid Waste Management WM-5 • Hold regular meetings to discuss and reinforce disposal procedures (incorporate into regular safety meetings). • Require that employees and subcontractors follow solid waste handling and storage procedures. • Prohibit littering by employees, subcontractors, and visitors. • Minimize production of solid waste materials wherever possible. Collection, Storage, and Disposal • Littering on the project site should be prohibited. • To prevent clogging of the storm drainage system, litter and debris removal from drainage grates, trash racks, and ditch lines should be a priority. • Trash receptacles should be provided in the contractor's yard, field trailer areas, and at locations where workers congregate for lunch and break periods. • Litter from work areas within the construction limits of the project site should be collected and placed in watertight dumpsters at least weekly, regardless of whether the litter was generated by the contractor, the public, or others. Collected litter and debris should not be placed in or next to drain inlets, stormwater drainage systems, or watercourses. • Dumpsters of sufficient size and number should be provided to contain the solid waste generated by the project. • Full dumpsters should be removed from the project site and the contents should be disposed of by the trash hauling contractor. • Construction debris and waste should be removed from the site biweekly or more frequently as needed. • Construction material visible to the public should be stored or stacked in an orderly manner. • Stormwater runon should be prevented from contacting stored solid waste through the use of berms, dikes, or other temporary diversion structures or through the use of measures to elevate waste from site surfaces. • Solid waste storage areas should be located at least 50 ft from drainage facilities and watercourses and should not be located in areas prone to flooding or ponding. • Except during fair weather, construction and highway planting waste not stored in watertight dumpsters should be securely covered from wind and rain by covering the waste with tarps or plastic. • Segregate potentially hazardous waste from non-hazardous construction site waste. • Make sure that toxic liquid wastes (used oils, solvents, and paints) and chemicals (acids, pesticides, additives, curing compounds) are not disposed of in dumpsters designated for construction debris. January 2003 California Stormwater BMP Handbook 3 of 4 Construction www.cabmphandbooks.com WM-5 Solid Waste Management r , , _0hazardous waste hauled to an appropriate disposal and/or recycling facility. • Salvage or recycle useful vegetation debris, packaging and surplus building materials when practical. For example, trees and shrubs from land clearing can be used as a brush barrier, or converted into wood chips, then used as mulch on graded areas. Wood pallets, cardboard boxes, and construction scraps can also be recycled. Costs All of the above are low cost measures. Inspection and Maintenance • Inspect and verify that activity-based BMPs are in place prior to the commencement of associated activities. While activities associated with the BMP are under way, inspect weekly during the rainy season and of two-week intervals in the non-rainy season to verify continued BMP implementation. • Inspect BMPs subject to non-stormwater discharge daily while non-stormwater discharges occur • Inspect construction waste area regularly. • Arrange for regular waste collection. /••"S References ( \twx Processes, Procedures and Methods to Control Pollution Resulting from All Construction Activity, 430/9-73-007, USEPA, 1973. Stormwater Quality Handbooks - Construction Site Best Management Practices (BMPs) Manual, State of California Department ot Transportation (Caltrans), November 2000. Stormwater Management for Construction Activities; Developing Pollution Prevention Plans and Best Management Practice, EPA 832^-92005; USEPA, April 1992. 4 of 4 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Hazardous Waste Management WM-6 Description and Purpose Prevent or reduce the discharge of pollutants to stormwater from hazardous waste through proper material use, waste disposal, and training of employees and subcontractors. Suitable Applications This best management practice (BMP) applies to all construction projects. Hazardous waste management practices are implemented on construction projects that generate waste from the use of: - Petroleum Products - Concrete Curing Compounds - Palliatives - Septic Wastes - Stains - Wood Preservatives - Asphalt Products - Pesticides - Acids - Paints - Solvents - Roofing Tar - Any materials deemed a hazardous waste in California, Title 22 Division 4.5, or listed in 40 CFR Parts no, 117, 261, or 302 Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: J Primary Objective / Secondary Objective Targeted Constituents Sediment Nutrients Trash Metals Bacteria * Oil and Grease Organics * Potential Alternatives None CASQA California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 6 Hazardous Waste Management WM-6 In addition, sites with existing structures may contain wastes, which must be disposed of in accordance with federal, state, and local regulations. These wastes include: • Sandblasting grit mixed with lead-, cadmium-, or chromium-based paints • Asbestos • PCBs (particularly in older transformers) Limitations • Hazardous waste that cannot be reused or recycled must be disposed of by a licensed hazardous waste hauler. • Nothing in this BMP relieves the contractor from responsibility for compliance with federal, state, and local laws regarding storage, handling, transportation, and disposal of hazardous wastes. • This BMP does not cover aerially deposited lead (ADL) soils. For ADL soils refer to WM-7, Contaminated Soil Management. Implementation The following steps will help reduce stormwater pollution from hazardous wastes: Material Use • Wastes should be stored in sealed containers constructed of a suitable material and should be labeled as required by Title 22 CCR, Division 4.5 and 49 CFR Parts 172, 173, 178, and 179. • All hazardous waste should be stored, transported, and disposed as required in Title 22 CCR, Division 4.5 and 49 CFR 261-263. • Waste containers should be stored in temporary containment facilities that should comply with the following requirements: Temporary containment facility should provide for a spill containment volume equal to 1.5 times the volume of all containers able to contain precipitation from a 25 year storm event, plus the greater of 10% of the aggregate volume of all containers or 100% of the capacity of the largest tank within its boundary, whichever is greater. - Temporary containment facility should be impervious to the materials stored there for a minimum contact time of 72 hours. Temporary containment facilities should be maintained free of accumulated rainwater and spills. In the event of spills or leaks, accumulated rainwater and spills should be placed into drums after each rainfall. These liquids should be handled as a hazardous waste unless testing determines them to be non-hazardous. Non-hazardous liquids should be sent to an approved disposal site. Sufficient separation should be provided between stored containers to allow for spill cleanup and emergency response access. 2 of 6 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Hazardous Waste Management WM-6 - Incompatible materials, such as chlorine and ammonia, should not be stored in the same temporary containment facility. Throughout the rainy season, temporary containment facilities should be covered during non-working days, and prior to rain events. Covered facilities may include use of plastic tarps for small facilities or constructed roofs with overhangs. • Drums should not be overfilled and wastes should not be mixed. • Unless watertight, containers of dry waste should be stored on pallets. • Do not over-apply herbicides and pesticides. Prepare only the amount needed. Follow the recommended usage instructions. Over application is expensive and environmentally harmful. Apply surface dressings in several smaller applications, as opposed to one large application. Allow time for infiltration and avoid excess material being carried offsite by runoff. Do not apply these chemicals just before it rains. People applying pesticides must be certified in accordance with federal and state regulations. • Paint brushes and equipment for water and oil based paints should be cleaned within a contained area and should not be allowed to contaminate site soils, watercourses, or drainage systems. Waste paints, thinners, solvents, residues, and sludges that cannot be recycled or reused should be disposed of as hazardous waste. When thoroughly dry, latex paint and paint cans, used brushes, rags, absorbent materials, and drop cloths should be disposed of as solid waste. • Do not clean out brushes or rinse paint containers into the dirt, street, gutter, storm drain, or stream. "Paint out" brushes as much as possible. Rinse water-based paints to the sanitary sewer. Filter and reuse thinners and solvents. Dispose of excess oil-based paints and sludge as hazardous waste. • The following actions should be taken with respect to temporary contaminant: Ensure that adequate hazardous waste storage volume is available. Ensure that hazardous waste collection containers are conveniently located. Designate hazardous waste storage areas onsite away from storm drains or watercourses and away from moving vehicles and equipment to prevent accidental spills. Minimize production or generation of hazardous materials and hazardous waste on the job site. Use containment berms in fueling and maintenance areas and where the potential for spills is high. Segregate potentially hazardous waste from non-hazardous construction site debris. Keep liquid or semi-liquid hazardous waste in appropriate containers (closed drums or similar) and under cover. January 2003 California Stormwater BMP Handbook 3 of 6 Construction www.cabmphandbooks.com Hazardous Waste Management WM-6 Clearly label all hazardous waste containers with the waste being stored and the date of accumulation. - Place hazardous waste containers in secondary containment. Do not allow potentially hazardous waste materials to accumulate on the ground. Do not mix wastes. - Use all of the product before disposing of the container. Do not remove the original product label; it contains important safety and disposal Waste Recycling Disposal m Se1 ated hazardous waste collection areas onsite. • , aoi. .„ materials and wastes should be stored in covered containers and protected from vandalism. rdous waste containers in secondary containment. • Du not i. vastes, this can cause chemical reactions, making recycling impossible and complicating disposal. • Recycle any useful materials such as used oil or water-based paint. • Make sure that toxic liquid wastes (used oils, solvents, and paints) and chemicals (acids, pesticides, additives, curing compounds) are not disposed of in dumpsters designated for construction debris. • Arrange for regular waste collection before containers overflow. • Make sure that hazardous waste (e.g., excess oil-based paint and sludge) is collected, removed, and disposed of only at authorized disposal areas. Disposal Procedures • Waste should be disposed of by a licensed hazardous waste transporter at an authorized and licensed disposal facility or recycling facility utilizing properly completed Uniform Hazardous Waste Manifest forms. • A Department of Health Services certified laboratory should sample waste to determine the appropriate disposal facility. • Properly dispose of rainwater in secondary containment that may have mixed with hazardous waste. • Attention is directed to "Hazardous Material", "Contaminated Material", and "Aerially Deposited Lead" of the contract documents regarding the handling and disposal of hazardous materials. 4 of 6 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Hazardous Waste Management WM-6 Education m Educate employees and subcontractors on hazardous waste storage and disposal procedures. • Educate employees and subcontractors on potential dangers to humans and the environment from hazardous wastes. • Instruct employees and subcontractors on safety procedures for common construction site hazardous wastes. • Instruct employees and subcontractors in identification of hazardous and solid waste. • Hold regular meetings to discuss and reinforce hazardous waste management procedures (incorporate into regular safety meetings). • The contractor's superintendent or representative should oversee and enforce proper hazardous waste management procedures and practices. • Make sure that hazardous waste is collected, removed, and disposed of only at authorized disposal areas. • Warning signs should be placed in areas recently treated with chemicals. • Place a stockpile of spill cleanup materials where it will be readily accessible. • If a container does spill, clean up immediately. Costs All of the above are low cost measures. Inspection and Maintenance m Inspect and verify that activity-based BMPs are in place prior to the commencement of associated activities. While activities associated with the BMP are under way, inspect weekly during the rainy season and of two week intervals in the non-rainy season to verify continued BMP implementation. • Inspect BMPs subject to non-stormwater discharge daily while non-stormwater discharges occur • Hazardous waste should be regularly collected. • A foreman or construction supervisor should monitor onsite hazardous waste storage and disposal procedures. • Waste storage areas should be kept clean, well organized, and equipped with ample cleanup supplies as appropriate for the materials being stored. • Perimeter controls, containment structures, covers, and liners should be repaired or replaced as needed to maintain proper function. • Hazardous spills should be cleaned up and reported in conformance with the applicable Material Safety Data Sheet (MSDS) and the instructions posted at the project site. January 2003 California Stormwater BMP Handbook 5 of 6 Construction www.cabmphandbooks.com Hazardous Waste Management WM-6 • The National Response Center, at (800) 424-8802, should be notified of spills of federal reportable quantities in conformance with the requirements in 40 CFR parts no, 117, and 302. Also notify the Governors Office of Emergency Services Warning Center at (916) 845- 8911. • A copy of the hazardous waste manifests should be provided. References Blueprint for a Clean Bay: Best Management Practices to Prevent Stormwater Pollution from Construction Related Activities; Santa Clara Valley Nonpoint Source Pollution Control Program, 1995- Processes, Procedures and Methods to Control Pollution Resulting from All Construction Activity, 430/9-73-007, USEPA, 1973. Stormwater Quality Handbooks - Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Stormwater Management for Construction Activities; Developing Pollution Prevention Plans and Best Management Practice, EPA 832^-92005; USEPA, April 1992. 6 of 6 California Stormwater BMP Handbook Construction www.cabmphandbooks.com January 2003 Contaminated Soil Management WM-7 Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and / Materials Pollution Control Legend: tr Primary Objective / Secondary Objective Description and Purpose Prevent or reduce the discharge of pollutants to stormwater from contaminated soil and highly acidic or alkaline soils by conducting pre-construction surveys, inspecting excavations regularly, and remediating contaminated soil promptly. Suitable Applications Contaminated soil management is implemented on construction projects in highly urbanized or industrial areas where soil contamination may have occurred due to spills, illicit discharges, aerial deposition, past use and leaks from underground storage tanks. Limitations Contaminated soils that cannot be treated onsite must be disposed of offsite by a licensed hazardous waste hauler. The presence of contaminated soil may indicate contaminated water as well. See NS-2, Dewatering Operations, for more information. The procedures and practices presented in this BMP are general. The contractor should identify appropriate practices and procedures for the specific contaminants known to exist or discovered onsite. Implementation Most owners and developers conduct pre-construction environmental assessments as a matter of routine. Contaminated soils are often identified during project planning and development with known locations identified in the plans, specifications and in the SWPPP. The contractor should review applicable reports and investigate appropriate call-outs in the plans, specifications, and Targeted Constituents Sediment Nutrients •/ Trash •/ Metals / Bacteria J Oil and Grease •/ Organics J Potential Alternatives None C \SQA .California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 5 Contaminated Soil Management WM-7 SWPPP. Recent court rulings holding contractors liable for cleanup costs when they unknowingly move contaminated soil highlight the need for contractors to confirm a site assessment is completed before earth moving begins. The following steps will help reduce stormwater pollution from contaminated soil: • Conduct thorough, pre-construction inspections of the site and review documents related to the site. If inspection or reviews indicated presence of contaminated soils, develop a plan before starting work. • Look for contaminated soil as evidenced by discoloration, odors, differences in soil properties, abandoned underground tanks or pipes, or buried debris. • Prevent leaks and spills. Contaminated soil can be expensive to treat and dispose of properly. However, addressing the problem before construction is much less expensive than after the structures are in place. • The contractor may further identify contaminated soils by investigating: Past site uses and activities Detected or undetected spills and leaks Acid or alkaline solutions from exposed soil or rock formations high in acid or alkaline forming elements Contaminated soil as evidenced by discoloration, odors, differences in soil properties, abandoned underground tanks or pipes, or buried debris. Suspected soils should be tested at a certified laboratory. Education m Have employees and subcontractors complete a safety training program which meets 29 CFR 1910.120 and 8 CCR 5192 covering the potential hazards as identified, prior to performing any excavation work at the locations containing material classified as hazardous. • Educate employees and subcontractors in identification of contaminated soil and on contaminated soil handling and disposal procedures. • Hold regular meetings to discuss and reinforce disposal procedures (incorporate into regular safety meetings). Handling Procedures for Material with Aerially Deposited Lead (ADL) • Materials from areas designated as containing (ADL) may, if allowed by the contract special provisions, be excavated, transported, and used in the construction of embankments and/or backfill. m Excavation, transportation, and placement operations should result in no visible dust. • Caution should be exercised to prevent spillage of lead containing material during transport. 2 of 5 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Contaminated Soil Management WM-7 • Quality should be monitored during excavation of soils contaminated with lead. Handling Procedures for Contaminated Soils m Minimize onsite storage. Contaminated soil should be disposed of properly in accordance with all applicable regulations. All hazardous waste storage will comply with the requirements in Title 22, CCR, Sections 66265.250 to 66265.260. • Test suspected soils at an approved certified laboratory. • Work with the local regulatory agencies to develop options for treatment or disposal if the soil is contaminated. • Avoid temporary stockpiling of contaminated soils or hazardous material. • Take the following precautions if temporary stockpiling is necessary: Cover the stockpile with plastic sheeting or tarps. - Install a berm around the stockpile to prevent runoff from leaving the area. Do not stockpile in or near storm drains or watercourses. • Remove contaminated material and hazardous material on exteriors of transport vehicles and place either into the current transport vehicle or into the excavation prior to the vehicle leaving the exclusion zone. • Monitor the air quality continuously during excavation operations at all locations containing hazardous material. • Procure all permits and licenses, pay all charges and fees, and give all notices necessary and incident to the due and lawful prosecution of the work, including registration for transporting vehicles carrying the contaminated material and the hazardous material. • Collect water from decontamination procedures and treat or dispose of it at an appropriate disposal site. • Collect non-reusable protective equipment, once used by any personnel, and dispose of at an appropriate disposal site. • Install temporary security fence to surround and secure the exclusion zone. Remove fencing when no longer needed. • Excavate, transport, and dispose of contaminated material and hazardous material in accordance with the rules and regulations of the following agencies (the specifications of these agencies supersede the procedures outlined in this BMP): - United States Department of Transportation (USDOT) - United States Environmental Protection Agency (USEPA) California Environmental Protection Agency (CAL-EPA) January 2003 California Stormwater BMP Handbook 3 of 5 Construction www.cabmphandbooks.com Contaminated Soil Management WM-7 / ^. California Division of Occupation Safety and Health Administration (CAL-OSHA) ! <^^ Local regulatory agencies Procedures for Underground Storage Tank Removals • Prior to commencing tank removal operations, obtain the required underground storage tank removal permits and approval from the federal, state, and local agencies that have jurisdiction over such work. • To determine if it contains hazardous substances, arrange to have tested, any liquid or sludge found in the underground tank prior to its removal. • Following the tank removal, take soil samples beneath the excavated tank and perform analysis as required by the local agency representative(s). • The underground storage tank, any liquid or sludge found within the tank, and all contaminated substances and hazardous substances removed during the tank removal and transported to disposal facilities permitted to accept such waste. Water Control • All necessary precautions and preventive measures should be taken to prevent the flow of water, including ground water, from mixing with hazardous substances or underground storage tank excavations. Such preventative measures may consist of, but are not limited to, berms, cofferdams, grout curtains, freeze walls, and seal course concrete or any combination ^M^ thereof. ( ,%<j^ • If water does enter an excavation and becomes contaminated, such water, when necessary to proceed with the work, should be discharged to clean, closed top, watertight transportable holding tanks, treated, and disposed of in accordance with federal, state, and local laws. Costs Prevention of leaks and spills is inexpensive. Treatment or disposal of contaminated soil can be quite expensive. Inspection and Maintenance • Inspect and verify that activity-based BMPs are in place prior to the commencement of associated activities. While activities associated with the BMP are under way, inspect weekly during the rainy season and of two-week intervals in the non-rainy season to verify continued BMP implementation. • Arrange for contractor's Water Pollution Control Manager, foreman, and/or construction supervisor to monitor onsite contaminated soil storage and disposal procedures. • Monitor air quality continuously during excavation operations at all locations containing hazardous material. • Coordinate contaminated soils and hazardous substances/waste management with the appropriate federal, state, and local agencies. —, 4 of 5 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Contaminated Soil Management WM-7 • Implement WM-4, Spill Prevention and Control, to prevent leaks and spills as much as possible. References Blueprint for a Clean Bay: Best Management Practices to Prevent Stormwater Pollution from Construction Related Activities; Santa Clara Valley Nonpoint Source Pollution Control Program, 1995- Processes, Procedures and Methods to Control Pollution Resulting from All Construction Activity, 430/9-73-007, USEPA, 1973. Stormwater Quality Handbooks - Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Stormwater Management for Construction Activities; Developing Pollution Prevention Plans and Best Management Practice, EPA 832^-92005; USEPA, April 1992. January 2003 California Stormwater BMP Handbook 5 of 5 Construction www.cabmphandbooks.com Concrete Waste Management WM-8 CONCRETE 1 WASHOUT AREA Description and Purpose Prevent or reduce the discharge of pollutants to stormwater from concrete waste by conducting washout offsite, performing onsite washout in a designated area, and training employee and subcontractors. Suitable Applications Concrete waste management procedures and practices are implemented on construction projects where: • Concrete is used as a construction material or where concrete dust and debris result form demolition activities • Slurries containing portland cement concrete (PCC) or asphalt concrete (AC) are generated, such as from saw cutting, coring, grinding, grooving, and hydro-concrete demolition • Concrete trucks and other concrete-coated equipment are washed onsite • Mortar-mixing stations exist • See also NS-8, Vehicle and Equipment Cleaning Limitations • Offsite washout of concrete wastes may not always be possible. Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and / Materials Pollution Control Legend: J Primary Objective / Secondary Objective Targeted Constituents Sediment i Nutrients Trash Metals i Bacteria Oil and Grease Organics Potential Alternatives None .CASQA California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.corn 1 of 7 WM-8 _ Concrete Waste Management Implementation The following steps will help reduce stormwater pollution from concrete wastes: • Discuss the concrete management techniques described in this BMP (such as handling of concrete waste and washout) with the ready-mix concrete supplier before any deliveries are made. • Incorporate requirements for concrete waste management into material supplier and subcontractor agreements. • Store dry and wet materials under cover, away from drainage areas. • Avoid mixing excess amounts of fresh concrete. • Perform washout of concrete trucks offsite or in designated areas only. • Do not wash out concrete trucks into storm drains, open ditches, streets, or streams. • Do not allow excess concrete to be dumped onsite, except in designated areas. • For onsite washout: Locate washout area at least 50 feet from storm drains, open ditches, or water bodies. Do not allow runoff from this area by constructing a temporary pit or bermed area large enough for liquid and solid waste. Wash out wastes into the temporary pit where the concrete can set, be broken up, and then disposed properly. • Avoid creating runoff by draining water to a bermed or level area when washing concrete to remove fine particles and expose the aggregate. • Do not wash sweepings from exposed aggregate concrete into the street or storm drain. Collect and return sweepings to aggregate base stockpile or dispose in the trash. Education m Educate employees, subcontractors, and suppliers on the concrete waste management techniques described herein. • Arrange for contractor's superintendent or representative to oversee and enforce concrete waste management procedures. Concrete Slurry Wastes • PCC and AC waste should not be allowed to enter storm drains or watercourses. • PCC and AC waste should be collected and disposed of or placed in a temporary concrete washout facility. • A sign should be installed adjacent to each temporary concrete washout facility to inform concrete equipment operators to utilize the proper facilities. 2 of 7 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Concrete Waste Management WM-8 • Below grade concrete washout facilities are typical. Above grade facilities are used if excavation is not practical. • A foreman or construction supervisor should monitor onsite concrete working tasks, such as saw cutting, coring, grinding and grooving to ensure proper methods are implemented. • Saw-cut PCC slurry should not be allowed to enter storm drains or watercourses. Residue from grinding operations should be picked up by means of a vacuum attachment to the grinding machine. Saw cutting residue should not be allowed to flow across the pavement and should not be left on the surface of the pavement. See also NS-3, Paving and Grinding Operations; and WM-io, Liquid Waste Management. • Slurry residue should be vacuumed and disposed in a temporary pit (as described in OnSite Temporary Concrete Washout Facility, Concrete Transit Truck Washout Procedures, below) and allowed to dry. Dispose of dry slurry residue in accordance with WM-5, Solid Waste Management. Onsite Temporary Concrete Washout Facility, Transit Truck Washout Procedures • Temporary concrete washout facilities should be located a minimum of 50 ft from storm drain inlets, open drainage facilities, and watercourses. Each facility should be located away from construction traffic or access areas to prevent disturbance or tracking. • A sign should be installed adjacent to each washout facility to inform concrete equipment operators to utilize the proper facilities. • Temporary concrete washout facilities should be constructed above grade or below grade at the option of the contractor. Temporary concrete washout facilities should be constructed and maintained in sufficient quantity and size to contain all liquid and concrete waste generated by washout operations. • Temporary washout facilities should have a temporary pit or bermed areas of sufficient volume to completely contain all liquid and waste concrete materials generated during washout procedures. • Washout of concrete trucks should be performed in designated areas only. • Only concrete from mixer truck chutes should be washed into concrete wash out. • Concrete washout from concrete pumper bins can be washed into concrete pumper trucks and discharged into designated washout area or properly disposed of offsite. • Once concrete wastes are washed into the designated area and allowed to harden, the concrete should be broken up, removed, and disposed of per WM-5, Solid Waste Management. Dispose of hardened concrete on a regular basis. • Temporary Concrete Washout Facility (Type Above Grade) Temporary concrete washout facility (type above grade) should be constructed as shown on the details at the end of this BMP, with a recommended minimum length and January 2003 California Stormwater BMP Handbook 3 of 7 Construction www.cabmphandbooks.com WM-8 Concrete Waste Management minimum width of 10 ft, but with sufficient quantity and volume to contain all liquid and concrete waste generated by washout operations. Straw bales, wood stakes, and sandbag materials should conform to the provisions in SE- 9, Straw Bale Barrier. Plastic lining material should be a minimum of 10 mil in polyethylene sheeting and should be free of holes, tears, or other defects that compromise the impermeability of the material. • Temporary Concrete Washout Facility (Type Below Grade) - Temporary concrete washout facilities (type below grade) should be constructed as shown on the details at the end of this BMP, with a recommended minimum length and minimum width of 10 ft. The quantity and volume should be sufficient to contain all liquid and concrete waste generated by washout operations. Lath and flagging should be commercial type. Plastic lining material should be a minimum of 10 mil polyethylene sheeting and should be free of holes, tears, or other defects that compromise the impermeability of the material. Removal of Temporary Concrete Washout Facilities • When temporary concrete washout facilities are no longer required for the work, the hardened concrete should be removed and disposed of. Materials used to construct temporary concrete washout facilities should be removed from the site of the work and disposed of. « Holes, depressions or other ground disturbance caused by the removal of the temporary concrete washout facilities should be backfilled and repaired. Costs All of the above are low cost measures. Inspection and Maintenance • Inspect and verify that activity-based BMPs are in place prior to the commencement of associated activities. While activities associated with the BMP are under way, inspect weekly during the rainy season and of two-week intervals in the non-rainy season to verify continued BMP implementation. • Temporary concrete washout facilities should be maintained to provide adequate holding capacity with a minimum freeboard of 4 in. for above grade facilities and 12 in. for below grade facilities. Maintaining temporary concrete washout facilities should include removing and disposing of hardened concrete and returning the facilities to a functional condition. Hardened concrete materials should be removed and disposed of. • Washout facilities must be cleaned, or new facilities must be constructed and ready for use once the washout is 75% full. 4 of 7 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Concrete Waste Management WM-8 References Blueprint for a Clean Bay: Best Management Practices to Prevent Stormwater Pollution from Construction Related Activities; Santa Clara Valley Nonpoint Source Pollution Control Program, 1995- Stormwater Quality Handbooks - Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Stormwater Management for Construction Activities; Developing Pollution Prevention Plans and Best Management Practice, EPA 832-R-92OO5; USEPA, April 1992. January 2003 California Stormwater BMP Handbook 5 of 7 Construction www.cabmphandbooks.com WM-8 Concrete Waste Management o LATH & FLAGGIN ON ALL SIDES BER CO UJ > G\ vl — v 10 MIL PLASTIC LINI \ 0 N Ul 0 n o NG- 10' MIN a a a \ Y Y >- >-t / A/ A / -< X \ rx a a / 0 0 D SANDBAG SANDBAG- . 10 MIL PLASTIC LINING- PLAN NOT TO SCALE TYPE "BELOW GRADE" I (n UJ a: E 10' MIN 9 f 9 B isa \ aa ^ \-STAKE (TYP) BERM SECTION A-A NOT TO SCALE 10 MIL PLASTIC LINING WOOD FRAME SECURELY FASTENED AROUND ENTIRE PERIMETER WITH TWO STAKES SECTION B-B NOT TO SCALE TWO-STACKED- 2 X 12 ROUGH WOOD FRAME -10 MIL PLASTIC LINING PLAN NOT TO SCALE TYPE "ABOVE GRADE" 1. ACTUAL LAYOUT DETERMINED IN FIELD. 2. THE CONCRETE WASHOUT SIGN SHALL BE INSTALLED WITHIN 30 FT. OF THE TEMPORARY CONCRETE WASHOUT FACILITY. 6 of 7 California Stormwater BMP Handbook Construction www.cabmphandbooks.com January 2003 Concrete Waste Management WM-8 UJ or B 10' MIN \—STAKE (TYP) 1/8" DIA. STEEL WIRE- STAPLE DETAIL 10 MIL PLASTIC LINING PLAN -STRAW BALE (TYP) NOT TO SCALE TYPE "ABOVE GRADE"WITH STRAW BALES 3' 3' 0 o CONCRETE"'' WASHOUT1 Ot '««m@r PLYWOOD 48" X 24" -PAINTED WHITE -BLACK LETTERS 6" HEIGHT -0.5" LAGSCREWS -WOOD POST 3" X 3" X 8' CONCRETE WASHOUT SIGN DETAIL (OR EQUIVALENT) STAPLES (2 PER BALE)10 MIL PLASTIC LINING NATIVE MATERIAL- (OPTIONAL) WOOD OR METAL STAKES (2 PER BALE) SECTION B-B NOT TO SCALE BINDING WIRE STRAW BALE NOTES 1. ACTUAL LAYOUT DETERMINED IN FIELD. 2. THE CONCRETE WASHOUT SIGN SHALL BE INSTALLED WITHIN 30 FT. OF THE TEMPORARY CONCRETE WASHOUT FACILITY. January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com 7 of 7 Sanitary/Septic Waste Management WM-9 Description and Purpose Proper sanitary and septic waste management prevent the discharge of pollutants to stormwater from sanitary and septic waste by providing convenient, well-maintained facilities, and arranging for regular service and disposal. Suitable Applications Sanitary septic waste management practices are suitable for use at all construction sites that use temporary or portable sanitary and septic waste systems. Limitations None identified. Implementation Sanitary or septic wastes should be treated or disposed of in accordance with state and local requirements. In many cases, one contract with a local facility supplier will be all that it takes to make sure sanitary wastes are properly disposed. Storage and Disposal Procedures m Temporary sanitary facilities should be located away from drainage facilities, watercourses, and from traffic circulation. When subjected to high winds or risk of high winds, temporary sanitary facilities should be secured to prevent overturning. • Wastewater should not be discharged or buried within the project site. Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and /• Materials Pollution Control Legend: V Primary Objective / Secondary Objective Targeted Constituents Sediment Nutrients Trash • Metals Bacteria Oil and Grease Organics < Potential Alternatives None California Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbooks.com lof 3 WM-9 Sanitary/Septic Waste Management t ^• Sanitary and septic systems that discharge directly into sanitary sewer systems, where ( ,_J permissible, should comply with the local health agency, city, county, and sewer district requirements. • Only reputable, licensed sanitary and septic waste haulers should be used. • Sanitary facilities should be located in a convenient location. • Untreated raw wastewater should never be discharged or buried. • Temporary septic systems should treat wastes to appropriate levels before discharging. • If using an onsite disposal system (OSDS), such as a septic system, local health agency requirements must be followed. • Temporary sanitary facilities that discharge to the sanitary sewer system should be properly connected to avoid illicit discharges. • Sanitary and septic facilities should be maintained in good working order by a licensed service. • Regular waste collection by a licensed hauler should be arranged before facilities overflow. Education m Educate employees, subcontractors, and suppliers on sanitary and septic waste storage and disposal procedures. '. • Educate employees, subcontractors, and suppliers of potential dangers to humans and the environment from sanitary and septic wastes. • Instruct employees, subcontractors, and suppliers in identification of sanitary and septic waste. • Hold regular meetings to discuss and reinforce disposal procedures (incorporate into regular safety meetings). • Establish a continuing education program to indoctrinate new employees. Costs All of the above are low cost measures. Inspection and Maintenance • Inspect and verify that activity-based BMPs are in place prior to the commencement of associated activities. While activities associated with the BMP are under way, inspect weekly during the rainy season and of two-week intervals in the non-rainy season to verify continued BMP implementation. • Arrange for regular waste collection. • If high winds are expected, portable sanitary facilities must be secured with spikes or weighed down to prevent over turning. 2 of 3 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbooks.com Sanitary/Septic Waste Management WM-9 References Stormwater Quality Handbooks - Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. Stormwater Management for Construction Activities; Developing Pollution Prevention Plans and Best Management Practice, EPA 832-^92005; USEPA, April 1992. January 2003 California Stormwater BMP Handbook 3 of 3 Construction www.cabmphandbooks.com Liquid Waste Management WM-10 . , • Description and Purpose Liquid waste management includes procedures and practices to prevent discharge of pollutants to the storm drain system or to watercourses as a result of the creation, collection, and disposal of non-hazardous liquid wastes. Suitable Applications Liquid waste management is applicable to construction projects that generate any of the following non-hazardous by-products, residuals, or wastes: • Drilling slurries and drilling fluids • Grease-free and oil-free wastewater and rinse water • Dredgings • Other non-stormwater liquid discharges not permitted by separate permits Limitations • Disposal of some liquid wastes may be subject to specific laws and regulations or to requirements of other permits secured for the construction project (e.g., NPDES permits, Army Corps permits, Coastal Commission permits, etc.). • Liquid waste management does not apply to dewatering operations (NS-2 Dewatering Operations), solid waste management (WM-5, Solid Waste Management), hazardous wastes (WM-6, Hazardous Waste Management), or Objectives EC SE TC WE NS WM Erosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater Management Control Waste Management and Materials Pollution Control Legend: • Primary Objective / Secondary Objective Targeted Constituents Sediment I Nutrients t Trash I Metals I Bacteria Oil and Grease I Organics Potential Alternatives None llfornla Stormwater Quality Association January 2003 California Stormwater BMP Handbook Construction www.cabmphandbook.com Iof4 WM-10 _ Liquid Waste Management concrete slurry residue (WM-8, Concrete Waste Management). • Typical permitted non-stormwater discharges can include: water line flushing; landscape irrigation; diverted stream flows; rising ground waters; uncontaminated pumped ground water; discharges from potable water sources; foundation drains; irrigation water; springs; water from crawl space pumps; footing drains; lawn watering; flows from riparian habitats and wetlands; and discharges or flows from emergency fire fighting activities. Implementation General Practices m Instruct employees and subcontractors how to safely differentiate between non-hazardous liquid waste and potential or known hazardous liquid waste. • Instruct employees, subcontractors, and suppliers that it is unacceptable for any liquid waste to enter any storm drainage device, waterway, or receiving water. • Educate employees and subcontractors on liquid waste generating activities and liquid waste storage and disposal procedures. • Hold regular meetings to discuss and reinforce disposal procedures (incorporate into regular safety meetings). • Verify which non-stormwater discharges are permitted by the statewide NPDES permit; different regions might have different requirements not outlined in this permit. • Apply NS-8, Vehicle and Equipment Cleaning for managing wash water and rinse water from vehicle and equipment cleaning operations. Containing Liquid Wastes • Drilling residue and drilling fluids should not be allowed to enter storm drains and watercourses and should be disposed of. • If an appropriate location is available, drilling residue and drilling fluids that are exempt under Title 23, CCR § 25ii(g) may be dried by infiltration and evaporation in a containment facility constructed in conformance with the provisions concerning the Temporary Concrete Washout Facilities detailed in WM-8, Concrete Waste Management. • Liquid wastes generated as part of an operational procedure, such as water-laden dredged material and drilling mud, should be contained and not allowed to flow into drainage channels or receiving waters prior to treatment. • Liquid wastes should be contained in a controlled area such as a holding pit, sediment basin, roll-off bin, or portable tank. • Containment devices must be structurally sound and leak free. • Containment devices must be of sufficient quantity or volume to completely contain the liquid wastes generated. 2 of 4 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbook.com Liquid Waste Management WM-10 • Precautions should be taken to avoid spills or accidental releases of contained liquid wastes. Apply the education measures and spill response procedures outlined in WM-4, Spill Prevention and Control. • Containment areas or devices should not be located where accidental release of the contained liquid can threaten health or safety or discharge to water bodies, channels, or storm drains. Capturing Liquid Wastes • Capture all liquid wastes that have the potential to affect the storm drainage system (such as wash water and rinse water from cleaning walls or pavement), before they run off a surface. • Do not allow liquid wastes to flow or discharge uncontrolled. Use temporary dikes or berms to intercept flows and direct them to a containment area or device for capture. • Use a sediment trap (SE-3, Sediment Trap) for capturing and treating sediment laden liquid waste or capture in a containment device and allow sediment to settle. Disposing of Liquid Wastes • A typical method to handle liquid waste is to dewater the contained liquid waste, using procedures such as described in NS-2, Dewatering Operations, and SE-2, Sediment Basin, and dispose of resulting solids per WM-5, Solid Waste Management. • Methods of disposal for some liquid wastes may be prescribed in Water Quality Reports, NPDES permits, Environmental Impact Reports, 401 or 404 permits, and local agency discharge permits, etc. Review the SWPPP to see if disposal methods are identified. • Liquid wastes, such as from dredged material, may require testing and certification whether it is hazardous or not before a disposal method can be determined. • For disposal of hazardous waste, see WM-6, Hazardous Waste Management. • If necessary, further treat liquid wastes prior to disposal. Treatment may include, though is not limited to, sedimentation, filtration, and chemical neutralization. Costs Prevention costs for liquid waste management are minimal. Costs increase if cleanup or fines are involved. Inspection and Maintenance • Inspect and verify that activity-based BMPs are in place prior to the commencement of associated activities. While activities associated with the BMP are under way, inspect weekly during the rainy season and of two-week intervals in the non-rainy season to verify continued BMP implementation. • Inspect BMPs subject to non-stormwater discharge daily while non-stormwater discharges occur. January 2003 California Stormwater BMP Handbook 3 of 4 Construction www.cabmphandbook.com WM-10 Liquid Waste Management • Remove deposited solids in containment areas and capturing devices as needed and at the completion of the task. Dispose of any solids as described in WM-5, Solid Waste Management. • Inspect containment areas and capturing devices and repair as needed. References Stormwater Quality Handbooks - Construction Site Best Management Practices (BMPs) Manual, State of California Department of Transportation (Caltrans), November 2000. O 4 of 4 California Stormwater BMP Handbook January 2003 Construction www.cabmphandbook.com APPENDIX K