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Home My WebLink AboutCT 05-15; La Costa Oaks North Neigh 3.1 & 3.3-3.5; Storm Water Quality; 2007-02-14HUNSAKER ^ASSOCIATES SAN DIEGO, INC. PLANNING ENGINEERING SURVEYING IRVINE LOS ANGELES RIVERSIDE SAN DIEGO STORM WATER MANAGEMENT PLAN for LA COSTA OAKS NORTH NEIGHBORHOOD 3.1 & 3.3 - 3.5 RECEIVED FEB202007 ENGINEERING DEPARTMENT City of Carlsbad, California DAVE HAMMAR LEX WILLIMAN ALISAVIALPANDO DAN SMITH RAY MARTIN CHUCK CATER 10179 Huennekens St. San Diego, CA 92121 (858) 558-4500 PH (858) 558-1414 FX www.HunsakerSD.com lnfo@HunsakerSD.com Prepared for: Real Estate Collateral Management Company c/o Morrow Development 1903 Wright Place, Suite 180 Carlsbad, CA 92008 W.O. 2352-151 February 12, 2007 Hunsaker & Associates San Diego, Inc. David A. Blalock, R.C.E. Associate oUJ o _J DG:kc h:\reports\2352M51\finalswmp-02.doc w.o.2352-151 2/12/2007 12:45 PM - K\ '• TABLE OF CONTENTS CHAPTER 1 - Executive Summary 1.1 Introduction 1.2 Summary of Pre-Developed Conditions 1.3 Summary of Proposed Development 1.4 Results and Recommendations 1.5 Conclusion 1.6 References CHAPTER 2 - Storm Water Criteria 2.1 Regional Water Quality Control Board Criteria 2.2 City of Carlsbad SUSMP Criteria CHAPTER 3 - Identification of Typical Pollutants 3.1 Anticipated Pollutants from Project Site 3.2 Sediment 3.3 Nutrients 3.4 Trash & Debris 3.5 Oxygen-Demanding Substances 3.6 Oil & Grease 3.7 Bacteria and Viruses 3.8 Pesticides CHAPTER 4 - Conditions of Concern 4.1 Receiving Watershed Descriptions 4.2 Pollutants of Concern in Receiving Watersheds 4.3 303 (d) Status 4.4 Condition of Concern - Developed Condition Hydrology Summary 4.5 Identification of Primary & Secondary Pollutants of Concern La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan CHAPTER 5 - Treatment Control BMP Design 5.1 BMP Locations 5.2 Determination of Treatment Flows 5.3 BMP Unit Sizing 5.4 Vortechs Treatment Units 5.5 Pollutant Removal Efficiency Table 5.6 BMP Unit Discussion CHAPTER 6 - Source Control BMPs 6.1 Landscaping 6.2 Urban Housekeeping 6.3 Automobile Use 6.4 Integrated Pest Management (IPM) Principles 6.5 Storm Water Conveyance Systems Stenciling and Signage 6.6 Efficient Irrigation Practices 6.7 Trash Storage Areas CHAPTER 7 - Site Design BMPs 7.1 Site Design BMPs 7.2 Minimize Impervious Footprint 7.3 Conserve Natural Areas 7.4 Permeable Pavements 7.5 Minimize Directly Connected Impervious Areas 7.6 Slopes & Channel Protection / Hillside Landscaping 7.7 Private Roads CHAPTER 8 - Operations & Maintenance Plan 8.1 Maintenance Requirements 8.2 Operations and Maintenance Plan 8.3 Annual Operations & Maintenance Costs OE:<Jja h:\reports\2352\151\flnal swmp-02.doc w.o.2352-151 2/12/2007 12:22 PM La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan List of Tables and Figures Chapter 1 - Vicinity Map Chapter 1 - Watershed Map Chapter 1 - BMP Location Map Chapter 2 - Storm Water Requirements Applicability Checklist Chapter 3 - Pollutant Category Table Chapter 4 - 2006 CWA Section 303(d) List Chapter 4 - Beneficial Uses of Inland Surface Waters Chapter 4 - Water Quality Objectives Chapter 5 - Pollutant Removal Efficiency Table Chapter 5 - Design Runoff Determination Summary Table Chapter 5 - BMP Location Map Chapter 5 - 85th Percentile Rational Method Calculations Chapter 5 - Vortechs System Data Attachments BMP LOCATION EXHIBIT (Pocket) DRAINAGE EXHIBITS (Pocket) DE:ad h:\reportstt352VI51tfnalswmp-01.doc w.o.2352-151 10/4/20069:42 AM La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan CHAPTER 1 - EXECUTIVE SUMMARY 1.1 -Introduction The La Costa Oaks North Neighborhoods 3.1 & 3.3 - 3.5 sites are located at the north eastern corner of the intersection of Poinsettia Lane and Alicante Road in the City of Carlsbad, California (see Vicinity Map below). Per the City of Carlsbad SUSMP, the La Costa Oaks North Neighborhoods 3.1 & 3.3 - 3.5 are classified as Priority Projects and are subject to the City's Permanent Storm Water BMP Requirements. This Storm Water Management Plan (SWMP) has been prepared pursuant to requirements set forth in the City of Carlsbad's "Standard Urban Storm Water Mitigation Plan (SUSMP)." All calculations are consistent with criteria set forth by the Regional Water Quality Control Board's Order No. 2001-01, and the City of Carlsbad SUSMP. This SWMP recommends the location and sizing of four (4) Best Management Practice (BMP) treatment units, which will treat 85th percentile runoff prior to discharging from the development site (see BMP Location Map in this chapter). Furthermore, this report determines anticipated project pollutants, pollutants of concern in the receiving watershed, recommended source control BMPs, and methodology used for the design of flow-based BMPs. PROJECT SITE VICINITY MAP NTS DE:ad h:\reports\2352M51tfinalswtnp-01.doc w 0.2352-151 10/4/2006 9:42 AM La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan 1.2 - Summary of Pre-Developed Conditions The La Costa Oaks North Neighborhoods 3.1, 3.3 - 3.5 sites are located in the City of Carlsbad, California. The site has been mass graded in anticipation for residential development per the "Mass Graded Hydrology Study for La Costa Oaks North - Neighborhood 3.1 & 3.3 - 3.5"dated October, 2005 by Hunsaker & Associates. 1.2.1 Neighborhood 3.1 Runoff from the La Costa Oaks North Neighborhood 3.1 site is drained via an existing 42-inch RCP storm drain to the receiving storm drain located within the adjacent Rancho Santa Fe Road, ultimately discharging to San Marcos Creek. 1.2.2 Neighborhood 3.3 Runoff from the La Costa Oaks North Neighborhood 3.3 site drains to four (4) existing storm drain outlet locations. Three (3) drainage locations (18-inch, 36-inch and 42-inch RCP's) discharge site runoff to the receiving storm drain located within the adjacent Rancho Santa Fe Road, ultimately discharging to San Marcos Creek. Flow directed to the south of the project site is intercepted via an existing 48-inch RCP, discharging to the receiving San Marcos Creek. 1.2.3 Neighborhood 3.4 & 3.5 Runoff from the La Costa Oaks North Neighborhoods 3.4 & 3.5 site drains to two (2) existing storm drain outlet locations. Runoff from the mass graded Neighborhood 3.4 site drains north to the receiving 36-inch RCP storm drain within San Elijo Road, discharging to the storm drain system within the adjacent Rancho Santa Fe Road. Runoff from the mass graded Neighborhood 3.5 site drains south to the receiving 48-inch RCP storm drain that discharges directly to San Marcos Creek. All flow from the La Costa Oaks North project site ultimately drains to San Marcos Creek. The Regional Water Quality Control Board has identified San Marcos Creek as part of the Carlsbad Hydrologic Unit, San Marcos Hydrologic Area, and the Batiquitos Hydrologic Subarea (basin number 904.51). Table 1 on the following page summarizes pre-developed conditions peak flows for Neighborhoods 3.1, 3.3 - 3.5. DE:ad h:\reportsV2352M51Minalswmp-01.doc w.o.2352-151 1CM/2006 9:42 AM LA COSTA OAKS NORTH WATERSHED MAP FOR LA COSTA OAKS NORTH . CITY OF CARLSBAD. CALIFORNIA La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan Table 1 - Summary of Pre-Developed Peak Flows Drainage Location 48-inch RCP to San Marcos Creek 18-inch RCP to Rancho Santa Fe Road (Avenida Soledad) 36-inch RCP to Rancho Santa Fe Road (San Elijo Road at Node 325) 42-inch RCP to Rancho Santa Fe Road Neighborhoods 3.3, 3.4 & 3.5 3.3 3.4 3.1, 3.3 & 3.4 TOTAL Drainage Area (Ac) 21.2 3.0 8.9 45.7 78.8 100-Year Peak Flow (cfs) 53.0 8.7 20.9 105.2 787.8 *Note: Inclusive of tributary areas from 3.1 & 3.3 - 3.5 1.3 - Summary of Proposed Development 1.3.1 Neighborhood 3.1 The proposed La Costa Oaks North Neighborhood 3.1 will consist of 80 single family residences, roads, sidewalks, curbs and gutters, associated underground utilities and storm water drainage systems. Runoff from the residential development will be conveyed via curb and gutter, where curb inlets will intercept this flow and convey it to the proposed storm drain system. This storm drain system connects to the existing 42-inch RCP storm drain, discharging to the existing storm drain system located within the adjacent Rancho Santa Fe Road. Based on County of San Diego 2003 Engineering Standards criteria, a runoff coefficient of 0.52 was assumed for the proposed single-family residential development. Prior to discharge from the site, a single flow based BMP is located at the end of the La Costa Oaks North Neighborhood 3.1 storm drain for storm water treatment. 85th percentile flow from the site and portions of the neighboring La Costa Oaks North Neighborhood 3.3 will be treated via this existing Vortechnics flow based treatment unit. DE:djg h:\reports\2352\151\final swmp-02.doc w.o.2352-151 2/7/2007 4:46 PM La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan 1.3.2 Neighborhood 3.3 The proposed La Costa Oaks North Neighborhood 3.3 will consist of 120 single * family residences, roads, sidewalks, curbs and gutters, associated underground ^ utilities and storm water drainage systems. Runoff from the northern portion of the residential development will be conveyed via m curb and gutter, where curb inlets will intercept this flow and convey it to the proposed storm drain system. This northern storm drain system connects to the * existing 42-inch RCP storm drain, discharging to the existing storm drain system m located within the adjacent Rancho Santa Fe Road. * Runoff from the southern portion of the residential development will be conveyed via « curb and gutter, where curb inlets will intercept this flow and convey it to the proposed storm drain system. This southern storm drain system connects to the existing 48-inch RCP storm drain to the south of the project site, discharging to the * receiving San Marcos Creek. Runoff from a small portion to the south east of the La Costa Oaks North * Neighborhood 3.3 site discharges to the curb and gutter within Sitio Corazon, draining to both the storm drain system within Avenida Soledad and San Elijo Roads, ultimately discharging to the existing storm drain system within the adjacent •* Rancho Santa Fe Road. Based on County of San Diego 2003 Engineering Standards criteria, a runoff * coefficient of 0.52 was assumed for the proposed single-family residential development. ** Prior to discharge from the site, four (4) flow based BMPs are located at the end of the four (4) internal La Costa Oaks North storm drain systems for storm water treatment. 85th percentile flow from the site and portions of the neighboring La " Costa Oaks North Neighborhoods 3.1, 3.4 & 3.5 will be treated via these existing Vortechnics flow based treatment units. 1.3.3 Neighborhood 3.4 & 3.5 w, The proposed La Costa Oaks North Neighborhoods 3.4 & 3.5 will consist of 83 ** single family residences, roads, sidewalks, curbs and gutters, associated underground utilities and storm water drainage systems. Runoff from the northern Neighborhood 3.4 portion will be conveyed via curb and gutter, where curb inlets will intercept this flow and convey it to the proposed storm drain system. This storm drain system connects to the existing 36-inch RCP storm drain within San Elijo Road, discharging to the existing storm drain system located within the adjacent Rancho Santa Fe Road. Runoff from the southern Neighborhood 3.5 will be conveyed via curb and gutter, where curb inlets will intercept this flow and convey it to the proposed storm drain OE:ad h:\refxjrts\2352\151\flnalswmp-01.doc w.o.2352-151 1<V4/200e 9:42 AM La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan Runoff from the southern Neighborhood 3.5 will be conveyed via curb and gutter, where curb inlets will intercept this flow and convey it to the proposed storm drain system. This storm drain system connects to the existing 48-inch RCP storm drain to the south of the project site, discharging to the receiving San Marcos Creek. Based on County of San Diego 2003 Engineering Standards criteria, a runoff coefficient of 0.52 was assumed for the proposed single-family residential development. Prior to discharge from the site, two (2) flow based BMPs area located at the end of the two (2) internal La Costa Oaks North storm drain systems for storm water treatment. 85th percentile flow from the site and portions of the neighboring La Costa Oaks North Neighborhood 3.3 will be treated via these existing Vortechnics flow based treatment units. Per the "Drainage Study for La Costa Oaks North Neighborhoods 3.1 & 3.3 - 3.5", dated October 2006 by Hunsaker & Associates, peak flow data from the developed site is summarized in Table 2 below. Table 2 - Summary of Developed Conditions Peak Flows Drainage Location 48-inch RCP to San Marcos Creek 18-inch RCP to Rancho Santa Fe Road (Avenida Soledad) 36-inch RCP to Rancho Santa Fe Road (San Elijo Road) 42-inch RCP to Rancho Santa Fe Road Neighborhoods 3.3, 3.4 & 3.5 3.3 3.4 3.1, 3.3 & 3.4 TOTAL Drainage Area (Ac) 21.0* 2.9* 8.8* 45.8* 78.5 100-Year Peak Flow (cfs) 44.3 7.7 20.2 98.4 170.6 *Note: Inclusive of tributary areas from 3.1 & 3.3 - 3.5 DG:djg h:\reports\2352\151 oaks north rough 3.1, 3.3,3.4 & 3.5\final swmp-02.doc w.o.2352-151 2/15/2007 12:19 PM La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan 1.4 - Results and Recommendations Table 3 below summarizes rational method 85th percentile calculations for the proposed water quality treatment unit for the La Costa Oaks North Neighborhood 3.1 & 3.3 - 3.5 developments. The runoff coefficient used for sizing the proposed treatment units is of 0.52, which was based on 283 dwelling units per 78.5 acres. Table 3 - Developed Conditions 85th Percentile Calculations Treatment Unit Location 48-inch RCPto San Marcos Creek 18-inch RCPto Rancho Santa Fe Road 36-inch RCPto Rancho Santa Fe Road 42-inch RCPto Rancho Santa Fe Road Neighborhoods 3.3, 3.4 & 3.5 3.3 3.4 3.1, 3.3 & 3.4 Drainage Area (acres) 21.0* 2.9* 8.8* 45.8* Rainfall Intensity (inches/hour) 0.2 0.2 0.2 0.2 Runoff Coefficient 0.52 0.52 0.52 0.52 85th Percentile Flow (cfs) 2.2 0.3 0.9 4.8 *=inclusive of portions of Neighborhoods 3.1, 3.4 & 3.5 Rational Method calculations predicted 85th percentile runoff flows of approximately 2. 2 cfs, 0.3 cfs, 0.9 cfs and 4.8 cfs at the respective four (4) flow based treatment units. Vortechs Models 4000,1000, 2000 & 7000 treatment units with respective treatment flow capacities of 6.0 cfs, 1.6 cfs, 2.8 cfs & 11 cfs are recommended. The Vortechnics treatment units are offline pre-cast treatment units. The 85th percentile design flow rate is forced into the treatment area by a diversion weir built in the upstream junction. Flows in excess of the design flow rate pass over the weir and proceed downstream. DE:ad h:\reports\2352M51\finalswmp-01.aoc w.o.2352-151 10/4/2006 9:42 AM t. 3 :a :: VICINITY MAP CONSTRUCTION NOTES: SITE DESIGN BMP: 42-INCH RCP TO RANCHO SANTA FE ROAD 36-INCH RCP TO RANCHO SANTA FE ROAD 18-INCH RCP TO RANCHO SANTA FE ROAD 48-INCH RCP TO RANCHO SANTA FE ROAD I - MINIMIZE IMPERVIOUS FOOTPRINT - CONSERVE NATURAL AREAS - PERMEABLE PAVEMENTS - MINIMIZE DIRECTLY CONNECTED IMPERVIOUS AREAS - SLOPE & CHANNEL PROTECTION / HILLSIDE LANDSCAPING - PRIVATE ROADS SOURCE CONTROL - LANDSCAPING - URBAN HOUSEKEEPING - AUTOMOBILE USE - INTEGRATED PEST MANAGEMENT (IMP) PRINCIPLES - STORM WATER CONVEYANCE SYSTEMS STENCILING AND SIGNAGE - TRASH STORAGE AREAS - EFFICIENT IRRIGATION PRACTICES STREETSWEEPING LEGEND WATERSHED BOUNDARY FLOWLINE PREPARED BY: HUNSAKER& ASSOCIATES I A H DllCft INC BMP LOCATION MAP FOR SHEET LA COSTA OAKS NORTH 1 NEIGHBORHOODS 3.1 & 3.3 - 3.5 OF CITY OF CARLSBAD, CALIFORNIA La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan 1.5-Conclusion The combination of proposed construction and permanent BMP's will reduce, to the maximum extent practicable, the expected project pollutants and will not adversely impact the beneficial uses of the receiving waters. DE:ad h:\reports\2352\151\finalsimip-01.doc w.o.2352-151 10/4/2006 9:42 AM La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan 1.6-References "Standard Urban Storm Water Mitigation Plan - Storm Water Standards", City of Carlsbad, April 2003. "City of Carlsbad Engineering Standards"; Volume 1 - General Design Standards; Chapter 5 - Drainage and Storm Drain Standards; City of Carlsbad, California; June 2004. "Master Drainage and Storm Water Quality Management Plan", City of Carlsbad, California; March 1994. "Mass Graded Hydrology Study for La Costa Oaks North - Neighborhood 3.1 & 3.3 - 3.5", Hunsaker & Associates San Diego, Inc.; October 2005. "San Diego County Hydrology Manual", County of San Diego Department of Public Works - Flood Control Section; June 2003. "Preliminary Hydrology for Villages of La Costa The Ridge & The Oaks", Hunsaker & Associates, San Diego, Inc. April 25, 2001. "Order No. 2001-01, NPDES No. CAS0108758- Waste Discharge Requirements for Discharges of Urban Runoff from the Municipal Separate Storm Sewer Systems (MS4s) Draining the Watersheds of the County of San Diego, the Incorporated Cities of San Diego County, and San Diego Unified Port District", California Regional Water Quality Control Board - San Diego Region; February 21, 2001. "Water Quality Plan for the San Diego Basin", California Regional Water Quality Control Board - San Diego Region, Septembers, 1994. "Vortechnics Storm Water Treatment System Manual", Vortechnics; Revised May 2000. Drawing No. 368-2. "Rancho Santa Fe Road". Dokken Engineering. July 7, 2002. Drawing No. 368-2B. "Rancho Santa Fe Road". Dokken Engineering. August 27, 2003. "Drainage Study for La Costa Oaks North - Neighborhoods 3.1, 3.3 - 3.5", Hunsaker & Associates San Diego, Inc.; October, 2006. DE:ad h:\reports\2352\151\fmalswmp-0t.doc w.o.2352-151 10/4/2006 9:42 AM II m La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Planm CHAPTER 2 - STORM WATER CRITERIA * 2.1 - Regional Water Quality Control Board Criteria 'm m All runoff conveyed in the proposed storm drain systems will be treated in compliance with Regional Water Quality Control Board regulations and NPDES criteria prior to discharging to natural watercourses. California Regional Water * Quality Control Board Order No. 2001-01, dated February 21, 2001, sets waste discharge requirements for discharges of urban runoff from municipal storm * separate drainage systems draining the watersheds of San Diego County. *Per the RWQCB Order, post-development runoff from a site shall not contain ** pollutant loads which cause or contribute to an exceedance of receiving water * quality objectives or which have not been reduced to the maximum extent practicable. Post-construction Best Management Practices (BMPs), which refer to " specific storm water management techniques that are applied to manage •" construction and post-construction site runoff and minimize erosion, include source control - aimed at reducing the amount of sediment and other pollutants - and treatment controls that keep soil and other pollutants onsite once they have been *" loosened by storm water erosion. Post construction pollutants are a result of the urban development of the property •"" and the effects of automobile use. Runoff from paved surfaces can contain both sediment (in the form of silt and sand) as well as a variety of pollutants transported by the sediment. Landscape activities by homeowners are an additional source of ** sediment. All structural BMPs shall be located to infiltrate, filter, or treat the required runoff volume or flow (based on the 85th percentile rainfall) prior to its discharge to any receiving watercourse supporting beneficial uses. * 2.2 - City of Carlsbad SUSMP Criteria Per the City of Carlsbad SUSMP, the La Costa Oaks North Neighborhoods 3.1 & 3.3 * - 3.5 are classified as Priority Projects and are subject to the City's Permanent Storm Water BMP Requirements. These requirements required the preparation of m this Storm Water Management Plan. « The Storm Water Applicability Checklist, which must be included along with Precise — Grading Plans applications, is included on the following page. DE:ad h:\reports\2352\151\finalswmp-01.doc w.o.2352-151 10/4/2006 9:42 AM Storm Water Standards 4/03/03 APPENDIX A STORM WATER REQUIREMENTS APPLICABILITY CHECKLIST Complete Sections 1 and 2 of the following checklist to determine your project's permanent and construction storm water best management practices requirements. This form must be completed and submitted with your permit application. Section 1. Permanent Storm Water BMP Requirements: If any answers to Part A are answered "Yes," your project is subject to the "Priority Project Permanent Storm Water BMP Requirements," and "Standard Permanent Storm Water BMP Requirements" in Section III, "Permanent Storm Water BMP Selection Procedure" in the Storm Water Standards manual. If all answers to Part A are "No," and any answers to Part B are "Yes," your project is only subject to the "Standard Permanent Storm Water BMP Requirements". If every question in Part A and B is answered "No," your project is exempt from permanent storm water 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 . Detached residential development of 10 or more units 2. Attached residential development of 1 0 or more units 3. Commercial development greater than 1 00,000 square feet 4. Automotive repair shop 5. Restaurant 6. Steep hillside development greater than 5,000 sqyare feet 7. Project discharging to receiving waters within Environmentally Sensitive Areas 8. Parking lots greater than or equal to 5,000 ft* or with at least 1 5 parking spaces, and potentially exposed to urban runoff 9. Streets, roads, highways, and freeways which would create a new paved surface that is 5,000 square feet or greater Yes V ^ s / No ,/ ••/ •" S if * Refer to the definitions section in the Storm Water Standards for expanded definitions of the priority project categories. Limited Exclusion: 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. 30 Storm Water Standards 4/03/03 Part B: Determine Standard Permanent Storm Water Requirements. Does the project propose: 1. New impervious areas, such as rooftops, roads, parking lots, driveways, paths and sidewalks? 2. New pervious landscape areas and irrigation systems? 3. Permanent structures within 1 00 feet of any natural water body? 4. Trash storage areas? 5. Liquid or solid material loading and unloading areas? 6. Vehicle or equipment fueling, washing, or maintenance areas? 7. Require a General NPDES Permit for Storm Water Discharges Associated with Industrial Activities (Except construction)?* 8. Commercial or industrial waste handling or storage, excluding typical office or household waste? 9. Any grading or ground disturbance during construction? 10. Any new storm drains, or alteration to existing storm drains? Yes No *To find out if your project is required to obtain an individual General NPDES Permit for Storm Water Discharges Associated with Industrial Activities, visit the State Water Resources Control Board web site at, www.swrcb.ca.gov/stormwtr/industrial.html Section 2. Construction Storm Water BMP Requirements: If the answer to question 1 of Part C is answered "Yes," your project is subject to Section IV, "Construction Storm Water BMP Performance Standards," and must prepare a Storm Water Pollution Prevention Plan (SWPPP). If the answer to question 1 is "No," but the answer to any of the remaining questions is "Yes," your project is subject to Section IV, "Construction Storm Water BMP Performance Standards," and must prepare a Water Pollution Control Plan (WPCP). If every question in Part C is answered "No," your project is exempt from any construction storm water BMP requirements. If any of the answers to the questions in Part C are "Yes," complete the construction site prioritization in Part D, below. Part C: Determine Construction Phase Storm Water Requirements. Would the project meet any of these criteria during construction? 1. Is the project subject to California's statewide General NPDES Permit for Storm Water Discharges Associated With Construction Activities? 2. Does the project propose cjrading or soil disturbance? 3. Would storm water or urban runoff have the potential to contact any portion of the construction area, including washing and staging areas? 4. 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 //\f / / No 31 Storm Water Standards 4/03/03 Part D: Determine Construction Site Priority In accordance with the Municipal Permit, each construction site with construction storm water BMP requirements must be designated with a priority: high, medium or low. This prioritization must be completed with this form, noted on the plans, and included in the SWPPP or WPCP. Indicate the project's priority in one of the check boxes using the criteria below, and existing and surrounding conditions of the project, the type of activities necessap' to complete the construction snd 3nw other extenuatin" circumstances that may pose a threat to water quality. The City reserves the right to adjust the priority of the projects both before and during construction. [Note: The construction priority does NOT change construction BMP requirements that apply to projects; all construction BMP requirements must be identified on a case-by-case basis. The construction priority does affect the frequency of inspections that will be conducted by City staff. See Section IV.1 for more details on construction BMP requirements.] A) High Priority 1) Projects where the site is 50 acres or more and grading will occur during the rainy season 2) Projects 5 acres or more. 3) 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 sensitive water bodies Q B) Medium Priority 1) 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.) 2) 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. 3) Permit projects on private property where grading permits are required, however, Notice Of Intents (NOIs) and SWPPPs are not required. Q C) Low Priority 1) Capital Projects where minimal to no grading occurs, such as signal light and loop installations, street light installations, etc. 2) Permit projects in the public right-of-way where minimal to no grading occurs, such as pedestrian ramps, driveway additions, small retaining walls, etc. 3) Permit projects on private property where grading permits are not required, such as small retaining walls, single-family homes, small tenant improvements, etc. 32 Ill La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan CHAPTER 3 - IDENTIFICATION OF TYPICAL POLLUTANTS 3.1 - Anticipated Pollutants from Project Site The following table details typical anticipated and potential pollutants generated by various land use types. The La Costa Oaks North Neighborhoods 3.1, 3.3, 3.4 & 3.5 developments will consist of detached single-family residences. Thus, the Detached Residential Development category has been highlighted to clearly illustrate which general pollutant categories are anticipated from the project area. Priority Project Categories Detached Residential Development Attached Residential Development Commercial Development >1 00,000 ft2 Automotive Repair Shops Restaurants Hillside Development >5,000 ft2 Parking Lots Streets, Highways & Freeways Retail Gas Outlets General Pollutant Categories SedimentsX X p(i) X p(i) X NutrientsX X p(D X p(1) p(1) >J2 M«! X X X X OrganicCompoundsp(2) X(4)(5) X(4) X<4> 005-22%\- Q X X X X X X X X X OxygenDemandingSubstancesX pO) p(5) X X p(1) p(5) 0)10CQ £o o9 O X p(2) X X X X X X X Bacteria &VirusesX P p(3) X PesticidesX X p(5) X p(1) 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 if land use involves food or animal waste products. (4) Including petroleum hydrocarbons. (5) Including solvents. DE:ad h:\reports\2352\151Minalswnnp-01.doc w.o.2352-151 10/4/2006 9:42 AM La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan 3.2 - Sediment Soils or other surface materials eroded and then transported or deposited by the action of wind, water, ice, or gravity. Sediments can increase turbidity, clog fish gills, reduce spawning habitat, smother bottom dwelling organisms, and suppress aquatic vegetative growth. 3.3 - Nutrients Inorganic substances, such as nitrogen and phosphorous, that commonly exist in the form of mineral salts that are either dissolved or suspended in water. Primary sources of nutrients in urban runoff are fertilizers and eroded soils. Excessive discharge of nutrients to water bodies and streams can cause excessive aquatic algae and plant growth. Such excessive production, referred to as cultural eutrophication, may lead to excessive decay of organic matter in the water body, loss of oxygen in the water, release of toxins in sediment, and the eventual death of aquatic organisms. 3.4 - Trash & Debris Examples include paper, plastic, leaves, grass cuttings, and food waste, which may have a significant impact on the recreational value of a water body and aquatic habitat. Excess organic matter can create a high biochemical oxygen demand in a stream and thereby lower its water quality. In areas where stagnant water is present, the presence of excess organic matter can promote septic conditions resulting in the growth of undesirable organisms and the release of odorous and hazardous compounds such as hydrogen sulfide. 3.5 - Oxygen-Demanding Substances Biodegradable organic material as well as chemicals that react with dissolved oxygen in water to form other compounds. Compounds such as ammonia and hydrogen sulfide are examples of oxygen-demanding compounds. The oxygen demand of a substance can lead to depletion of dissolved oxygen in a water body and possibly the development of septic conditions. 3.6 - Oil & Grease Characterized as high high-molecular weight organic compounds. Primary sources of oil and grease are petroleum hydrocarbon products, motor products from leaking vehicles, oils, waxes, and high-molecular weight fatty acids. Elevated oil and grease content can decrease the aesthetic value of the water body, as well as the water quality. DE:ad h:\reports\2352VI51\flnalswnip-01.doc w.o.2352-151 10/4/20069:42 AM La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan 3.7 - Bacteria and Viruses Bacteria and viruses are ubiquitous micro-organisms that thrive under certain environmental conditions. Their proliferation is typically caused by the transport of animals or human fecal wastes from the watershed. Water, containing excessive bacteria and viruses can alter the aquatic habitat and create a harmful environment for humans and aquatic life. Also, the decomposition of excess organic waste causes increased growth of undesirable organisms in the water. 3.8 - Pesticides Pesticides (including herbicides) are chemical compounds commonly used to control nuisance growth or prevalence of organisms. Excessive application of a pesticide may result in runoff containing toxic levels of its active component. DE:ad h:\reports\2352\151\final swmp-01.doc w.o.2352-151 10/4/2006 9:42 AM IV La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan CHAPTER 4 - CONDITIONS OF CONCERN 4.1 - Receiving Watershed Descriptions As shown in the watershed map on the following page, the pre-developed and post- developed La Costa Oaks North Neighborhoods 3.1 & 3.3 - 3.5 drain to the San Marcos Creek watershed. The Regional Water Quality Control Board has identified San Marcos Creek as part of the Carlsbad Hydrologic Unit, San Marcos Hydrologic Area, and the Batiquitos Hydrologic Subarea (basin number 904.51). 4.2 - Pollutants of Concern in Receiving Watersheds San Marcos Creek is listed on the EPA's 303(d) List of endangered waterways (included in this Chapter). Per the "Water Quality Plan for the San Diego Basin", the beneficial uses for San Marcos Creek include agricultural supply, contact water recreation, non-contact recreation, warm freshwater habitat, and wildlife habitat. In addition, San Marcos Creek is exempted as being designated as a Municipal water supply. Table 3-3 from the "Water Quality Plan for the San Diego Basin" (included at the end of this Chapter) lists water quality objectives for a variety of potential pollutants required to sustain the beneficial uses of the San Marcos hydrologic area. 4.3 - 303(d) Status Section 303(d) of the Federal Clean Water Act (CWA) requires the State to identify surface waters that do not meet applicable water quality standards with certain technology-based controls. The State Water Resources Control Board has approved the 2006 303(d) List of Water Quality Limited Segment. San Marcos Creek (hydrologic unit 904.51) is listed on the EPA's 303(d) List of endangered water bodies (included at the end of this chapter) as being sensitive to Bacteria, DDE (dichlorodiphenylethylene), Phosphorus and Sediment Toxicity. DE:ad h:\reports\2352\151\fnalswmp-01.doc w.o.2352-151 10/4/2006 9:42 AM WATERSHED MAP FOR LA COSTA OAKS NORTH . CfTY OF CARLSBAD, CALIFORNIA La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan 4.4 - Condition of Concern- Developed Condition Hydrology Summary 4.4.1 Neigborhood 3.1 The proposed La Costa Oaks North Neighborhood 3.1 will consist of 80 single family residences, roads, sidewalks, curbs and gutters, associated underground utilities and storm water drainage systems. Runoff from the residential development will be conveyed via curb and gutter, where curb inlets will intercept this flow and convey it to the proposed storm drain system. This storm drain system connects to the existing 42-inch RCP storm drain, discharging to the existing storm drain system located within the adjacent Rancho Santa Fe Road. Based on County of San Diego 2003 Engineering Standards criteria, a runoff coefficient of 0.52 was assumed for the proposed single-family residential development. 4.4.2 Neighborhood 3.3 The proposed La Costa Oaks North Neighborhood 3.3 will consist of 120 single family residences, roads, sidewalks, curbs and gutters, associated underground utilities and storm water drainage systems. Runoff from the northern portion of the residential development will be conveyed via curb and gutter, where curb inlets will intercept this flow and convey it to the proposed storm drain system. This northern storm drain system connects to the existing 42-inch RCP storm drain, discharging to the existing storm drain system located within the adjacent Rancho Santa Fe Road. Runoff from the southern portion of the residential development will be conveyed via curb and gutter, where curb inlets will intercept this flow and convey it to the proposed storm drain system. This southern storm drain system connects to the existing 48-inch RCP storm drain to the south of the project site, discharging to the receiving San Marcos Creek. Runoff from a small portion to the south east of the La Costa Oaks North Neighborhood 3.3 site discharges to the curb and gutter within Sitio Corazon, draining to both the storm drain system within Avienda Soledad and San Elijo Roads, ultimately discharging to the existing storm drain system within the adjacent Rancho Santa Fe Road. Based on County of San Diego 2003 Engineering Standards criteria, a runoff coefficient of 0.52 was assumed for the proposed single-family residential development. DE:ad h:\recorts\2352M51\finalswmp-01.doc w.o.2352-151 10/4/2006 9:42 AM La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan 4.4.3 Neighborhood 3.4 & 3.5 The proposed La Costa Oaks North Neighborhoods 3.4 & 3.5 will consist of 83 single family residences, roads, sidewalks, curbs and gutters, associated underground utilities and storm water drainage systems. Runoff from the northern Neighborhood 3.4 portion will be conveyed via curb and gutter, where curb inlets will intercept this flow and convey it to the proposed storm drain system. This storm drain system connects to the existing 36-inch RCP storm drain within San Elijo Road, discharging to the existing storm drain system located within the adjacent Rancho Santa Fe Road. Runoff from the southern Neighborhood 3.5 will be conveyed via curb and gutter, where curb inlets will intercept this flow and convey it to the proposed storm drain system. This storm drain system connects to the existing 48-inch RCP storm drain to the south of the project site, discharging to the receiving San Marcos Creek. Based on County of San Diego 2003 Engineering Standards criteria, a runoff coefficient of 0.52 was assumed for the proposed single-family residential development. Per the "Drainage Study for La Costa Oaks North Neighborhoods 3.1 & 3.3 - 3.5", dated October 2006 by Hunsaker & Associates, peak flow data from the developed site is summarized in Table 3 below. Table 3 - Summary of Developed Conditions Peak Flows Drainage Location 48-inch RCP to San Marcos Creek 18-inch RCP to Rancho Santa Fe Road (Avenida Soledad) 36-inch RCP to Rancho Santa Fe Road (San Elijo Road) 42-inch RCP to Rancho Santa Fe Road Neighborhoods 3.3, 3.4 & 3.5 3.3 3.4 3.1, 3.3 & 3.4 TOTAL Drainage Area (Ac) 21.0* 2.9* 8.8* 45.8* 78.5 100-Year Peak Flow (cfs) 44.3 7.7 20.2 98.4 170.6 'Note: Inclusive of tributary areas from 3.1, 3.3, 3.4 & 3.5 DG:djg h:\reportsV2352\151 oaks north rough 3.1, 3.3.3.4 & 3.5\flrd swmp-02.doc w.o.2352-151 2/15/2007 12:09 PM La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan Table 4 - Summary of Pre Vs Post Developed Peak Flows Conditions Existing Developed Difference Drainage Area (Ac) 78.8* 78.5 -0.3 100-Year Peak Flow (cfs) 187.8 170.6 -17.2 * 0.3 Acres accounted from San Elijo Road in Mass Graded 4.5 - Identification of Primary & Secondary Pollutants of Concern As stated previously in segment 4., the nearest 303(d) listed endangered water body the La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 is tributary to is San Marcos Creek. This water body is listed as being sensitive Bacteria, DDE (dichlorodiphenylethylene), Phosphorus and Sediment Toxicity. Thus, primary pollutants of concern from the proposed single family residential development include Bacteria, Sediments, Nutrients and Pesticides. Secondary pollutants generated by the project site include Trash and Debris, Oxygen Demanding Substances and Oil & Grease. DG-dia h:\reports\2352V151 oaks north rough 3.1, 3.3.3.4 & 3.5M)nal swmp-a2.doc w.o.2352-151 2/16/2007 12:10 PM Table 2-2. BENEFICIAL USES OF INLAND SURFACE WATERS 1,2 Inland Surface Waters Hydrqlogic Unit Basin Number BENEFICIAL USE M U N A G R I N D P R 0 C G W R F R S H P O W R E C 1 R E C 2 B I O L W A R M C 0 L D W I L D R A R E S P W N San Diego County Coastal Streams -continued • . Buena Vista Lagoon Buena Vista Creek Buena Vista Creek Agua Hsdlonda Agua Hedionda Creek Buena Creek Agua Hedionda Creek Letterbox canyon Canyon de las Encinas 4.21 4.22 4.21 4.31 4.32 4:32 4.31 4.31 4.40 See Coastal Waters- Table 2-3 + + « • « e , • • • • • • • •• See Coastal Waters- Table 2-3 • • a • + o o • • • • • • • • • • O • • • • • • • • • • • • • • • San Marcos Creek Watershed Batlqultos Lagoon San Marcos Creek unnamed intermittent streams 4.51 4.52 4.53 See Coastal Waters- Table 2-3 + + • • • • • • • • • • • San Marcos Creek Watershed San Marcos Creek Encinitas Creek 4.51 4.51 + + o « • « • • • • • • • Existing Beneficial Use O Potential Beneficial Use + Excepted From MUN (See Text) Waterbodies are listed multiple times If they cross hydrologic area or sub area boundaries. ' Beneficial use designations apply to all tributaries to the indicated waterbody, if not listed separately. Table 2-2 BENEFICIAL USES March 12, 1997 2-27 "N Table 3-2. WATER QUALITY OBJECTIVES Concentrations not to be exceeded more than 10% of the time during any one one year period. Inland Surface Waters Hydrologic Unit Basin Number Constitiuent (mg/L or as noted) TDS Cl SO 4 %Na N&P Fe Mn MBAS B ODOR Turb NTU Color Units F SAN LUIS REY HYDROLOGIC UNIT 903.00 Lower San Luis HA Monserat HA Warner Valley HA 3.10 3.20 3.30 500 500 500 250 250 250 250 250 250 60 60 60 a a a 0.3 0.3 0.3 0.05 0.05 0.05 0.5 0.5 0.5 0.75 0.75 0.75 none none none 20 20 20 20 20 20 1.0 1.0 1.0 CARLSBAD HYDROLOGIC UNIT 904.00 Loma Alta HA Buena Vista Creek HA Agua Hedionda HA Encinas HA San Marcos HA Escondido Creek HA 4.10 4.20 4.30 4.40 4.50 4.60 - 500 500 - 500 500 - 250 250 - 250 250 - 250 250 - 250 250 - 60 60 - 60 60 - a a - a a - 0.3 0.3 - 0.3 0.3 - 0.05 0.05 - 0.05 0.05 - 0.5 0.5 - 0.5 0.5 - 0.75 0.75 - 0.75 0.75 none none none none none none 20 20 20 20 20 20 20 20 20 20 20 20 1.0 1.0 1.0 1.0 1.0 1.0 SAN DIEGUITO HYDROLOGIC UNIT 905.00 Solana Beach HA Hodges HA San Pasqual HA Santa Maria Valley HA Santa Ysabel HA . 5.10 5.20 5.30 5.40 5.50 500 600 500 500 500 250 250 250 250 250 250 250 250 250 250 60 60 60 60 60 a a a a a 0.3 0.3 0.3 0.3 0.3 0.05 0.05 0.05 0.05 0.05 0.5 0.5 0.5 0.5 0.5 0.75 0.75 0.75 0.75 0.75 none none none none none 20 20 20 20 20 20 20 20 20 20 1.0 1.0 1.0 1.0 1.0 PENASQUITOS HYDROLOGIC UNIT 906.00 Miramar Reservoir HA Poway HA 6.10 6.20 500 500 260 250 260 250 60 60 a a 0.3 0.3 0.05 0.05 0.6 0.5 0.75 0.75 none none 20 20 20 20 1.0 1.0 HA - Hydrologic Area HSA - Hydrologic Sub Area (Lowor case letters indicate endnotos following the table.) Table 3-2 WATER QUALITY OBJECTIVES Pago 3-23 September 8. 1994 i i. Table 2-3. BENEFICIAL USES OF COASTAL WATERS Coastal Waters Pacific Ocean Dana Point Harbor Del Mar Boat Basin Mission Bay Oceanslde Harbor San Diego Bay ' Hydrologic Unit Basin Number BENEFICIAL USE i N D © © © 9 © N A V 9 9 9 9 R E C 1 9 © 0 9 © R E C 2 © © © 0 • c .0 M M 9 9 o o © B I 0 L 9 E S T e © w I L D • 9 • 9 • • R A R E • 0 • 9 o o M A R O O 0 • 0 0 A Q U A © M I G R «> «> €> €» €» C> s p w N 9 • • • ' O O W A R M S H E L L © 9 9 9 9 9 Coastal Lagoons Tijuana River Estuary Mouth of San Diego River Los Penasquitos Lagoon San Dieguito Lagoon Batiquitos. Lagoon San Elijo Lagoon Aqua Hedionda Lagoon •n.i'i 7.11 6.10 5.11 4.51 . 5.61 4.31 9 0 0 9 © © © ® 9 © © © ffi • ® • © e o o • • 9 • 9 • •• •' •» i> •* d C' • • 9 9 9 9 9 ••[--.'-•-•_• 9 9 9 9 ;"? 1 Includes the tidal prisms of the Otay and Sweetwater Rivers. 2 Fishing from shore or boat permitted, but other water contact recreational (REC-1) uses are prohibited. 9 Existing Beneficial Use March 12, 1997 Table 2-3 BENEFICIAL USES 2-47 mm PROPOSED 2006 CWA SECTION 303(d) LIST OF WATER QUALITY LIMITED SEGMENTS SAN DIEGO REGIONAL BOARD SVVRCB DRAFT 303(cl) LIST RELEASE DATE: SEPTEMBER 15, 2006 REGION TYPE NAME CALWATER WATERSHED POLLUTANT/STRESSOR POTENTIAL SOURCES ESTIMATED PROPOSED TMDL SIZE AFFECTED COMPLETION 9 C Pacific Ocean Shoreline, San Joaquin Hills 90111000 HSA 9 C Pacific Ocean Shoreline, San Luis Rey HU 90311000 9 C Pacific Ocean Shoreline, San Marcos HA 90451000 9 C Pacific Ocean Shoreline, Scripps HA 90630000 9 C Pacific Ocean Shoreline, Tijuana HU 91111000 9 R Pine Valley Creek (Upper) 91141000 Indicator bacteria 0.63 Miles 2005 Impairment located at Cameo Cove at Irvine Cove Dr./Riviera Way, Heisler Park-North Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source Indicator bacteria 0.49 Miles 2005 Impairment located at San Luis Rey River Mouth. Nonpoint/Point Source Indicator bacteria 0.5 Miles 2005 Impairment located at Moonlight State Beach. Nonpoint/Point Source Indicator bacteria 3.9 Miles 2019 This listing for indicator bacteria onliy applies to the Childrens Pool Beach area of this ocean shoreline segment. Nonpoint/Point Source Indicator bacteria Impairment located from the border, extending north along the shore. Nonpoint/Point Source Enterococcus 3 Miles 2.9 Miles 2010 2010 Phosphorus Grazing-Related Sources Concentrated Animal Feeding Operations (permitted, point source) Transient encampments Source Unknown 2.9 Miles 2019 Printout: 9/13/2006 Page IS of 29 PROPOSED 2006 CWA SECTION 303(d) LIST OF WATER QUALITY LIMITED SEGMENTS SAN DIEGO REGIONAL BOARD SWRCB DRAFT 303(d) LIST RELEASE DATE: SEPTEMBER 15, 2006 REGION TYPE NAME CALWATER WATERSHED POLLUTANT/STRESSOR POTENTIAL SOURCES ESTIMATED PROPOSED TMDL SIZE AFFECTED COMPLETION 9 R San Juan Creek 9 E San Juan Creek (mouth) 9 R San Luis Rey River 9 R San Marcos Creek 90120000 90120000 90311000 90451000 DDE Indicator bacteria Indicator bacteria Source Unknown Nonpoint/Point Source Nonpoint/Point Source Chloride Impairment located at lower 13 miles. Urban Runoff/Storm Sewers Unknown Nonpoint Source Total Dissolved Solids DDE Phosphorus Unknown point source 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 Source Unknown Source Unknown 1 Miles 1 Miles 6.3 Acres 19 Miles 19 Miles 19 Miles 19 Miles 2019 2005 2008 2019 2019 2019 2019 Printout: 9/13/2006 Page 22 of 29 PROPOSED 2006 CWA SECTION 303(d) LIST OF WATER QUALITY LIMITED SEGMENTS SAN DIEGO REGIONAL BOARD SVVRCB DRAFT 303(d) LIST RELEASE DATE: SEPTEMBER 15, 2006 REGION TYPE NAME CALWATER WATERSHED POLLUTANT/STRESSOR POTENTIAL SOURCES ESTIMATED PROPOSED TMDL SIZE AFFECTED COMPLETION 9 L San Marcos Lake 9 L San Vicente Reservoir 9 R Sandia Creek Printout: 9/13/2006 90452000 90721000 90222000 Sediment Toxicity Ammonia as Nitrogen Nutrients Phosphorus Chloride Color Manganese pH (high) Sulfates Total Dissolved Solids Iron Source Unknown Source Unknown Source Unknown Source Unknown Source Unknown Source Unknown Source Unknown Source Unknown Source Unknown Source Unknown Source Unknown 19 Miles 17 Acres 17 Acres 17 Acres 1058 Acres 1058 Acres 1058 Acres 1058 Acres 1058 Acres 1058 Acres 1.5 Miles 2019 2019 2019 2019 2019 2019 2019 2019 2019 2019 2019 Page 23 of 29 V La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan CHAPTER 5 - TREATMENT CONTROL BMP DESIGN 5.1 - BMP Locations Four (4) Best Management Practice (BMP) treatment units will treat 85th percentile runoff prior to discharging from the La Costa Oaks North - Neighborhoods 3.1 & 3.3 -3.5. The map on the following page shows the location of the proposed BMPs. 5.2 - Determination of Treatment Flows Flow-based BMPs shall be designed to mitigate the maximum flowrate of runoff produced from a rainfall intensity of 0.2 inch per hour. Such BMPs utilize either mechanical devices (such as vaults that produce vortex effects) or non-mechanical devices (based on weir hydraulics and specially designed filters) to promote settling and removal of pollutants from the runoff. Per the request of the City of Carlsbad, 85th percentile flow calculations were performed using the Rational Method. The basic Rational Method runoff procedure is as follows: Design flow (Q) = C * I * A Runoff Coefficient (C) - In accordance with the County of San Diego standards, the weighted runoff coefficient for all the areas draining to the treatment unit was determined using the areas analyzed in the final engineering hydrology report. The runoff coefficient is based on the following characteristics of the watershed: Land Use - Single Family Residential in Developed Areas Soil Type - Hydrologic soil group D was assumed for all areas. Group D soils have very slow infiltration rates when thoroughly wetted. Consisting chiefly of clay soils with a high swelling potential, soils with a high permanent water table, soils with clay pan or clay layer at or near the surface, and shallow soils over nearly impervious materials, Group D soils have a very slow rate of water transmission. Rainfall Intensity (I) - Regional Water Quality Control Board regulations and NPDES criteria have established that flow-based BMPs shall be designed to mitigate a rainfall intensity of 0.2 inch per hour. Watershed Area (A) - Corresponds to total area draining to treatment unit. DE:ad h:\iEports\2352M51\Mswnp-01.doc W.O-2352-151 10/4/2000 9:45 AM •a INCH RCP TO RANCHO SANTA FE ROAD 36-INCH RCP TO RANCHO SANTA FE ROAD j- 18-INCH RCP TO RANCHO SANTA FE ROAD 48-INCH RCP TO RANCHO SANTA FE ROAD CONSTRUCTION NOTES: SITE DESIGN BMP:I - MINIMIZE IMPERVIOUS FOOTPRINT - CONSERVE NATURAL AREAS - PERMEABLE PAVEMENTS - MINIMIZE DIRECTLY CONNECTED IMPERVIOUS AREAS - SLOPE & CHANNEL PROTECTION / HILLSIDE LANDSCAPING - PRIVATE ROADS SOURCE CONTROL: - LANDSCAPING - URBAN HOUSEKEEPING - AUTOMOBILE USE - INTEGRATED PEST MANAGEMENT (IMP) PRINCIPLES - STORM WATER CONVEYANCE SYSTEMS STCNCIUNG AND SIGNAGE - TRASH STORAGE AREAS - EFFICIENT IRRIGATION PRACTICES - STREETSWEEPING LEGEND WATERSHED BOUNDARY FLOWLINE PREPARED BY: HUNSAKER & ASSOCIATES BMP LOCATION MAP FOR LA COSTA OAKS NORTH NEIGHBORHOODS 3.1 & 3.3 - 3.5 CITY OF CARLSBAD, CALIFORNIA SHEET 1 OF La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan Table 5 below summarizes rational method 85th percentile calculations for the proposed water quality treatment unit for the La Costa Oaks North Neighborhood 3.1 & 3.3 - 3.5 developments. The runoff coefficient used for sizing the proposed treatment units is of 0.52, which was based on 283 dwelling units per 78.5 acres. Table 5 - Developed Conditions 85th Percentile Calculations Treatment Unit Location 48-inch RCPto San Marcos Creek 18-inch RCPto Rancho Santa Fe Road 36-inch RCPto Rancho Santa Fe Road 42-inch RCPto Rancho Santa Fe Road Neighborhoods 3.3, 3.4 & 3.5 3.3 3.4 3.1, 3.3 & 3.4 Drainage Area (acres) 21.0* 2.9* 8.8* 45.8* Rainfall Intensity (inches/hour) 0.2 0.2 0.2 0.2 Runoff Coefficient 0.52 0.52 0.52 0.52 85th Percentile Flow (cfs) 2.2 0.3 0.9 4.8 *=inclusive of portions of Neighborhoods 3.1, 3.4 & 3.5 Rational Method calculations predicted 85th percentile runoff flows of approximately 2. 2 cfs, 0.3 cfs, 0.9 cfs and 4.8 cfs at the respective four (4) flow based treatment units. 5.3 - BMP Unit Sizing The Vortechs unit is an offline precast treatment unit. The 85th percentile design flow rate will be forced into the treatment area by a diversion weir built in the upstream junction. Flows in excess of the design flow rate pass over the weir and proceed downstream. The calculations determining the peak flows being forced into the treatment during a 100-year storm event will govern the sizing requirements necessary to adequately treat the entire flow passing through the unit during this significant rainfall event. DE:ad h:\reports\2352M5Hfinalswmp-01.doc w.o.2352-151 10/4/2006 9:42 AM La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan VORTECHS UNIT TREATMENT CAPACITY TABLE Treatment Unit 48-inch RCP to San Marcos Creek 18-inch RCP to Rancho Santa Fe Road 36-inch RCP to Rancho Santa Fe Road 42-inch RCP to Rancho Santa Fe Road 85th Pet. Design Flow (cfs) 2.2 0.3 0.9 4.8 Recommended Vortechs Model 4000 1000 2000 7000 Treatment Capacity (cfs) 6.0 1.6 2.8 11 5.4 - Vortechs Treatment Units The Vortechs Storm Water Treatment System is designed to efficiently remove grit, contaminated sediments, metals, hydrocarbons and floating contaminants from surface runoff. Combining swirl-concentrator and flow-control technologies to eliminate turbulence within the system, the Vortechs System ensures the effective capture of sediment and oils and prevents resuspension of trapped pollutants for flows up to 25 cfs. Other features of the Vortechs Systems include the following: Large capacity system provides an 80 percent net annual Total Suspended Solids (TSS) removal rate. Unit is installed below grade. Low pump-out volume and one-point access reduce maintenance costs. Design prevents oils and other floatables from escaping the system during cleanout. Enhanced removal efficiencies of nutrients and heavy metals with offline configuration. The tangential inlet to the system creates a swirling motion that directs settleable solids into a pile towards the center of the grit chamber. Sediment is caught in the swirling flow path and settles back onto the pile after the storm event is over. Floatable entrapment is achieved by sizing the low flow control to create a rise in the water level of the vault that is sufficient to just submerge the inlet pipe with the 85th percentile flow. DE:ad h:\repore\2352\151Vflnalswnip-01.doc w.o.2352-151 10M/2008 9:42 AM La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan 5.5 - Pollutant Removal Efficiency Table Pollutant of Concern Sediment Nutrients Heavy Metals Organic Compounds Trash & Debris Oxygen Demanding Substances Bacteria Oil & Grease Pesticides BMP Categories Hydrodynamic Separation Devices'2' M-H L-M L-M L-M M-H L L L-H L Vortechs'M Stormwater Treatment System H L-M L-M L-M H L L H L (1) The County will periodically assess the performance characteristics of these BMPs to update this table. (2) Proprietary Structural BMPs. Not all serve the same function. L (Low): Low removal efficiency (roughly 0-25%) M (Medium): Medium removal efficiency (roughly 25-75%) H (High): High removal efficiency (roughly 75-100%) U: Unknown removal efficiency, applicant must provide evidence supporting use 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 Developed Areas (2001). DE:ad h:\reports\2352\151\fmalswmp-01.doc W.O.2352-151 10/4/2006 9:42 AM La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan 5.6 - BMP Unit Selection Discussion 5.6.1 Extended Detention Basins Extended detention basins collect the first flush runoff volume and retain it in the basin for a period of 24-48 hours. 85th percentile runoff volume, contained below the overflow elevation of the basin riser, will be slowly discharged from the treatment control basin via low flow orifices in the basin riser. After passing through the riser, an outlet pipe will dewater the basin and discharge runoff to the natural drainage course downstream. Advantages • Due to the simplicity of design, extended detention basins are relatively easy and inexpensive to construct and operate. • Extended detentions basins can provide substantial capture of sediment and the toxics fraction associated with particulates. • Widespread application with sufficient capture volume can provide significant control of channel erosion and enlargement caused by changes to flow frequency relationships resulting from the increase of impervious cover in the watershed. Limitations • Limitation of the diameter of the orifice may not allow use of extended detention in watersheds of less than 5 acres (would require an orifice with a diameter of less than 0.5 inches that would be prone to clogging). • Dry extended detention ponds have only moderate pollutant removal when compared to some other structural stormwater practices, and they are relatively ineffective at removing soluble pollutants. • Dry ponds can detract from the value of a home due to the adverse aesthetics of dry, bare areas and inlet and outlet structures. Conclusion: Due to the minimal footprint area available for the BMP treatment units and multiple points of outlet, construction of extended detention basins is not a feasible option for the La Costa Oaks North - Neighborhoods 3.1 & 3.3 - 3.5 project site. DE:ad h:\reports\2352\151\final swmp-41.doc w.o.2352-151 10/4/2006 9:42 AM La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan 5.6.2 Vegetated Swale Vegetated swales are open, shallow channels with vegetation covering the side slopes and bottom that collect and slowly convey runoff through filtering by the vegetation in the channel, filtering through a subsoil matrix, and/or infiltration into the underlying soils. Swales can be natural or manmade. They trap particulate pollutants (suspended solids and trace metals), promote infiltration, and reduce the velocity of stormwater runoff. Vegetated swales can serve as part of a stormwater drainage system and can replace curbs, gutters and stormwater systems. Advantages • If properly designed, vegetated, and operated, swales can serve as an aesthetic, potentially inexpensive urban development or roadway drainage conveyance measure with significant collateral water quality benefits. Limitations • Can be difficult to avoid channelization. • May not be appropriate for industrial sites or locations where spills may occur. • Grassed swales cannot treat a very large drainage area. Large areas may be divided and treated using multiple swales. • A thick vegetative cover is needed for these practices to function properly. • They are impractical in areas with steep topography. • They are not effective and may even erode when flow velocities are high, if the grass cover is not properly maintained. • In some places, their use is restricted by law: many local municipalities require curb and gutter systems in residential areas. • Swales are more susceptible to failure if not properly maintained than other treatment BMPs. Conclusion: Proposed swales to line the sides of the proposed private roads has potential to undermine the serviceability of the adjacent roads and sidewalks. Also, due to the limited footprint available and multiple points of discharge within the project site for BMP treatment, master treatment swales are not a feasible treatment option. DE:ad h:\repons\23S2M51tflnalswnip-01.doc w.o.2352-151 1CM/2006 9:42 AM La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan 5.6.3 Infiltration Basins 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. Advantages • Provides 100% reduction in the load discharged to surface waters. • The principle benefit of infiltration basins is the approximation of pre- development hydrology during which a significant portion of the average 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. • Infiltration rates exceeding 2.4 inches/hour, the runoff should be 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. Conclusion: Due to the minimum footprint available within the project site, a filtration basin is not a viable alternative for the La Costa Oaks North - Neighborhoods 3.1 & 3.3 - 3.5 developments. DE:ad h:\report3\2352M51Wnal swrn^OI.doc w.o.2352-151 10/4/2006 9:42 AM La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan 5.6.4 Wet Ponds Wet ponds are constructed basins that have a permanent pool of water throughout the year (or at least throughout the wet season) and differ from constructed wetlands primarily in having a greater average depth. Ponds treat incoming stormwater runoff by settling and biological uptake. The primary removal mechanism is settling as stormwater runoff resides in this pool, but pollutant uptake, particularly of nutrients, also occurs to some degree through biological activity in the pond. Wet ponds are among the most widely used stormwater practices. While there are several different versions of the wet pond design, the most common modification is the extended detention wet pond, where storage is provided above the permanent pool in order to detain stormwater runoff and promote settling. Advantages • If properly designed, constructed and maintained, wet basins can provide substantial aesthetic/recreational value and wildlife and wetland habitat. • Ponds are often viewed as a public amenity when integrated with a park setting. • Due to the presence of the permanent wet pool, properly designed and maintained wet basins can provide significant water quality improvements across a relatively broad spectrum of constituents including dissolved nutrients. • Widespread application with sufficient capture volume can provide significant control of channel erosion and enlargement caused by changes to flow frequency relationships resulting from the increase of impervious cover in a watershed. Limitations • Some concern about safety when constructed where there is public access. • Mosquito and midge breeding is likely to occur in ponds. • Cannot be placed on steep unstable slopes. • Need for base flow or supplemental water if water level is to be maintained. • Require a relatively large footprint. • Depending on volume and depth, pond designs may require approval from the State Division of Safety of Dams. Conclusion: Due to the large acreage requirements of a wet pond, proximity to residences (vector issues) and the fact that other BMP's are able to treat pollutants of concern with equal efficiency, wet ponds are not a feasible option for the La Costa Oaks North - Neighborhoods 3.1 & 3.3 - 3.5 project site. DE:ad h:\reports\2352\151\finalswmp-01.doc w.o.2352-151 10/4/2006 9:42 AM La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan 5.6.5 Media Filters Stormwater media filters are usually two-chambered including a pre-treatment settling basin and a filter bed filled with sand or other absorptive filtering media. As stormwater flows into the first chamber, large particles settle out, and then finer particles and other pollutants are removed as stormwater flows through the filtering media in the second chamber. Advantages Relatively high pollutant removal, especially for sediment and associated pollutants. Widespread application with sufficient capture volume can provide significant control of channel erosion and enlargement caused by changes to flow frequency relationships resulting from the increase of impervious cover in a watershed. Limitations • More expensive to construct than many other BMP's. • May require more maintenance than some other BMP's depending upon the sizing of the filter bed. • Generally require more hydraulic head to operate properly (min 4 feet). • High solids loads will cause the filter to clog. • Work best for relatively small, impervious watersheds. • Filters in residential areas can present aesthetic and safety problems if constructed with vertical concrete walls. • Certain designs maintain permanent sources of standing water where mosquito's and midge breeding is likely to occur. Conclusion: Due to the minimal foot print area available and its maintenance frequency, media filters are not a feasible option to treat all developed flows for the La Costa Oaks North - Neighborhoods 3.1 & 3.3 - 3.5 project site. DE:ad h:\reports\2352\15nfinal swmp-01.doc w.o.2352-151 10/4/20069:42 AM La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan 5.6.6 Drainage Inserts Drainage inserts are manufactured filters or fabric placed in a drop inlet to remove sediment and debris. There are a multitude of inserts of various shapes and configurations, typically falling to one of three different groups: socks, boxes and trays. The sock consists of a fabric, usually constructed of polypropylene. The fabric may be attached to a frame or the grate of the inlet holds the sock. Socks are meant for vertical (drop) inlets. Boxes are constructed of plastic or wire mesh. Typically a polypropylene "bag" is placed in the wire mesh box. The bag takes form of the box. Most box products are one box; that is, the setting area and filtration through media occur in the same box. Some products consist of one or more trays and mesh grates. The trays may hold different types of media. Filtration media vary by manufacturer. Types include polypropylene, porous polymer, treated cellulose and activated carbon. Advantages • Does not require additional space as inserts as the drain inserts are already a component of the standard drainage systems. • Easy access for inspection and maintenance. • As there is no standing water, there is little concern for mosquito breeding. • A relatively inexpensive retrofit option. Limitations • Performance is likely significantly less than treatment systems that are located at the end of the drainage system such as ponds and vaults. • Usually not suited for large areas or areas with trash or leaves that can plug the insert. Conclusion: Due to site design constraints and poor levels of treatment effectiveness, curb inlet filters were deemed to be the less applicable BMP treatment option for the La Costa Oaks North - Neighborhoods 3.1 & 3.3 - 3.5 developments. DE:ad h:\reports\2352\151\finalswmp-01doc w.o.2352-151 10/4/20069:42 AM •m La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan 5.6.7 Hydrodynamic Separator Systems Hydrodynamic separators are flow-through structures with a settling or separation unit to remove sediments and other pollutants that are widely used in storm water treatment. No outside power source is required, because the energy of the flowing water allows the sediments to efficiently separate. Depending on the type of unit, this separation may be by means of swirl action or indirect filtration. Variations of this unit have been designed to meet specific needs. Hydrodynamic separators are most effective where the materials to be removed from runoff are heavy particulates - which can be settled - or floatables -which can be captured, rather than solids with poor settleability or dissolved pollutants. In addition to the standard units, some vendors offer supplemental features to reduce the velocity of the flow entering the system. This increases the efficiency of the unit by allowing more sediments to settle out. 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 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 matter (e.g., leaves) decomposes in the units. Conclusion When compared to other BMP treatment options, Hydro-dynamic separator units provided a good overall treatment solution due to limited foot print constraints, vector control, maintenance and treatment effectiveness criteria for the pollutants of concern generated by the La Costa Oaks North - Neighborhoods 3.1 & 3.3, 3.4 - 3.5 project site. DE:ad hAreportsOJ52\151\finalswmp-01.doc w.o.2352-151 KV4/2006 9:42 AM 85TH PERCENTILE PEAK FLOW AND VOLUME DETERMINATION Modified Rational Method - Effective for Watersheds < 1.0 mi2 Hunsaker & Associates - San Diego Note: Only Enter Values in Boxes - Spreadsheet Will Calculate Remaining Values Project Name Work Order Jurisdiction La Costa Oaks North - Neighborhoods 3.1 , 3.3, 3.4 & 3.5 | 2352-151 | City of Carlsbad | BMP Location |Vortechs Unit - Neighborhood 3.1 (42-inch RCP to Rancho Santa Fe Road | Developed Drainage Area = Natural Drainage Area = 45.8 [acres 0.0 I acres Total Drainage Area to BMP = 45.8 acres Dev. Area Runoff Coefficient = | 0.52 Nat. Area Runoff Coefficient = | Runoff Coefficient = 0.52 RATIONAL METHOD RESULTS Q = CIA where Q = 85th Percentile Peak Flow (cfs) C = Runoff Coefficient I = Rainfall Intensity (0.2 inch/hour per RWQCB mandate) A = Drainage Area (acres) Using the Total Drainage Area: C = 0.52 I = 0.2 inch/hour A = 45.8 acres Q =4.76 cfs H:\EXCEL\2352\151\85th.xlsN. 3.1 9/27/2006 m 85TH PERCENTILE PEAK FLOW AND VOLUME DETERMINATION Modified Rational Method - Effective for Watersheds < 1.0 mi2 Hunsaker & Associates - San Diego Note: Only Enter Values in Boxes - Spreadsheet Will Calculate Remaining Values Project Name Work Order Jurisdiction La Costa Oaks North - Neighborhoods 3.1 , 3.3, 3.4 & 3.5 | 2352-151 | City of Carlsbad | BMP Location |Vortechs Unit - Neighborhood 3.3 (48-inch RCP to San Marcos Creek) Developed Drainage Area = Natural Drainage Area = 21.0 0.0 Total Drainage Area to BMP = 21.0 acres acres acres Dev. Area Runoff Coefficient = I 0.52 Nat. Area Runoff Coefficient = | Runoff Coefficient = 0.52 RATIONAL METHOD RESULTS Q = CIA where Q = 85th Percentile Peak Flow (cfs) C = Runoff Coefficient I = Rainfall Intensity (0.2 inch/hour per RWQCB mandate) A = Drainage Area (acres) Using the Total Drainage Area: C = 0.52 I = 0.2 inch/hour A = 21.0 acres Q =2.18 cfs H:\EXCEL\2352\151\85th.xlsN. 3.3 - A 9/27/2006 85TH PERCENTILE PEAK FLOW AND VOLUME DETERMINATION Modified Rational Method - Effective for Watersheds < 1.0 mi2 Hunsaker & Associates - San Diego Note: Only Enter Values in Boxes - Spreadsheet Will Calculate Remaining Values Project Name Work Order Jurisdiction La Costa Oaks North - Neighborhoods 3.1 , 3.3, 3.4 & 3.5 | 2352-151 j City of Carlsbad | BMP Location |Vortechs Unit - Neighborhood 3.3 (18-inch RCP to Rancho Santa Fe Road) | Developed Drainage Area = Natural Drainage Area = 2.9 Total Drainage Area to BMP =Iacres acres 2.9 acres 0.0 Dev. Area Runoff Coefficient = I 0.52 Nat. Area Runoff Coefficient = | Runoff Coefficient = 0.52 RATIONAL METHOD RESULTS Q = CIA where Q = 85th Percentile Peak Flow (cfs) C = Runoff Coefficient I = Rainfall Intensity (0.2 inch/hour per RWQCB mandate) A = Drainage Area (acres) Using the Total Drainage Area: C = 0.52 I = 0.2 inch/hour A = 2.9 acres Q =0.30 cfs H:\EXCELA2352\151\85th.xlsN. 3.3 - B 9/27/2006 85TH PERCENTILE PEAK FLOW AND VOLUME DETERMINATION Modified Rational Method - Effective for Watersheds < 1.0 mi2 Hunsaker & Associates - San Diego Note: Only Enter Values in Boxes - Spreadsheet Will Calculate Remaining Values Project Name Work Order Jurisdiction La Costa Oaks North - Neighborhoods 3.1 , 3.3, 3.4 & 3.5 | 2352-151 | City of Carlsbad | BMP Location jVortechs Unit - Neighborhood 3.3 (36-inch RCP to Rancho Santa Fe Road) | Developed Drainage Area = Natural Drainage Area = Total Drainage Area to BMP = 8.8 0.0 8.8 acres acres acres Dev. Area Runoff Coefficient = Nat. Area Runoff Coefficient = Runoff Coefficient = RATIONAL METHOD RESULTS 0.52 0.52 Q = CIA where Q = 85th Percentile Peak Flow (cfs) C = Runoff Coefficient I = Rainfall Intensity (0.2 inch/hour per RWQCB mandate) A = Drainage Area (acres) Using the Total Drainage Area: C = 0.52 I = 0.2 inch/hour A = 8.8 acres Q =0.92 cfs H:\EXCEL\2352\151\85th.xlsN. 3.3 - C 9/27/2006 85TH PERCENTILE PEAK FLOW AND VOLUME DETERMINATION Modified Rational Method - Effective for Watersheds < 1.0 mi2 Hunsaker & Associates - San Diego Note: Only Enter Values in Boxes - Spreadsheet Will Calculate Remaining Values Project Name Work Order Jurisdiction La Costa Oaks North - Neighborhoods 3.1 , 3.3, 3.4 & 3.5 | 2352-151 | City of Carlsbad | BMP Location [Vortechs Unit - Neighborhood 3.3 (42-inch RCP to Rancho Santa Fe Road) | Developed Drainage Area = Natural Drainage Area = 45.8 Total Drainage Area to BMP = I acres ~"| acres 45.8 acres 0.0 Dev. Area Runoff Coefficient = Nat. Area Runoff Coefficient = Runoff Coefficient = RATIONAL METHOD RESULTS 0.52 0.52 Q = CIA where Q = 85th Percentile Peak Flow (cfs) C = Runoff Coefficient I = Rainfall Intensity (0.2 inch/hour per RWQCB mandate) A = Drainage Area (acres) Using the Total Drainage Area: C = 0.52 I = 0.2 inch/hour A = 45.8 acres Q =4.76 cfs H:\EXCEL\2352\151\85th.xlsN. 3.3 - D 9/27/2006 85TH PERCENTILE PEAK FLOW AND VOLUME DETERMINATION Modified Rational Method - Effective for Watersheds < 1.0 mi2 Hunsaker & Associates - San Diego Note: Only Enter Values in Boxes - Spreadsheet Will Calculate Remaining Values Project Name Work Order Jurisdiction La Costa Oaks North - Neighborhoods 3.1 , 3.3, 3.4 & 3.5 | 2352-151 j City of Carlsbad | BMP Location [Vortechs Unit - Neighborhood 3.4 & 3.5 (48-inch RCP to San Marcos Creek) | Developed Drainage Area = Natural Drainage Area = Total Drainage Area to BMP ; 21.0 I acres ~"| acres 21.0 acres 0.0 Dev. Area Runoff Coefficient = Nat. Area Runoff Coefficient = 0.52 Runoff Coefficient = 0.52 RATIONAL METHOD RESULTS Q = CIA where Q = 85th Percentile Peak Flow (cfs) C = Runoff Coefficient I = Rainfall Intensity (0.2 inch/hour per RWQCB mandate) A = Drainage Area (acres) Using the Total Drainage Area: C = 0.52 I = 0.2 inch/hour A= 21.0 acres Q =2.18 cfs H:\EXCEL\2352\151\85th.xlsN. 3.4 & 3.5 - A 9/27/2006 85TH PERCENTILE PEAK FLOW AND VOLUME DETERMINATION Modified Rational Method - Effective for Watersheds < 1.0 mi2 Hunsaker & Associates - San Diego Note: Only Enter Values in Boxes - Spreadsheet Will Calculate Remaining Values Project Name Work Order Jurisdiction La Costa Oaks North - Neighborhoods 3.1 , 3.3, 3.4 & 3.5 | 2352-151 | City of Carlsbad | BMP Location |Vortechs Unit - Neighborhood 3.4 & 3.5 (36-inch RCP to Rancho Santa Fe Road) Developed Drainage Area = Natural Drainage Area = Total Drainage Area to BMP = 8.8 acres acres 8.8 acres 0.0 Dev. Area Runoff Coefficient = Nat. Area Runoff Coefficient = Runoff Coefficient = RATIONAL METHOD RESULTS 0.52 0.52 Q = CIA where Q = C = A = Using the Total Drainage Area: C = l = A = 85th Percentile Peak Flow (cfs) Runoff Coefficient Rainfall Intensity (0.2 inch/hour per RWQCB mandate) Drainage Area (acres) 0.52 0.2 inch/hour 8.8 acres Q =0.92 cfs H:\EXCEL\2352\151\85th.xlsN. 3.4 & 3.5 - B 9/27/2006 the W)rtec1._Stormwater Treatment System D Plus 6' Typical Perforated Covers^ \y \j 1 \*. T 3' to 4' } Plan View To begin the design of your Vortechs System, refer to the sizing chart below and com- plete a Specifier's Worksheet to provide details about your site and design flows. Then simply fax or mail the worksheet to Vortechnics with your site plan, and we'll produce detailed Vortechs System scale draw- ings free of charge. Elevation View :^-mmmm a.B 4.5 B.D 8.5 11.0 ^^ '3.25: s. sizing criteria.n ••"••'; B] Sediment'storaga'yqiurtie.assumes.a 3 foot sump.:::.'-~f^'::r::;l:~^-^;-f^!^'f&''^'^iS<!^fl>^f3f^i^^u';! .'•'•.' p]:'Construction details 'may va^V depending onjthe-spECific1 application. Any alterations to the'sizmg.chart spEcifi-".. • -'-^./catiarTS will appear on Vortschnics dimensional and shop drawings. Please call Vortechnics fcr.the weight of spe-... • -. ^cific Vbrtechs systems if needed: •; •;. • • /?:,'C'.: •^^Ki^^'-.t'^Sf 's'--'A'^:SA^-l']^y^' :?.".•.;;"=':.*!• '•..:::'..:':.; • •'.'•' Special Note: CSi storage capacity^.wheriit is heeded tbftieet a-specific requirement for.spill containment;-can be' . -: sized to meet the storage requirement with-the selected model. Vortechnics technical staff" will optimize-system : '? .-ii..geomecrY'to'.meit qontainrnentrequirements within a carrecdy sized Vortechs-System:.,>.:,-:-':>|tVv;.^.- "•".^ ;"'.;•:"'.': .ft = MfiScSpeoSca£ion' Chart available, by calling Vartsctinics'atfSO?} B7B3BB2.''i^f-:.'':'-':'.';j'\k. V'V::v"-.^^''i:-'.'.j.r:-r Vortechs System Inlet/Outlet Configurations Vortechs Systems can be configured to accommo- date various inlet and outlet pipe orientations. The inlet pipe can enter the end or side of the tank at right angles - outlet pipes can exit the end or the side of system at most angles. End Inlet 11 Side Inlet To Polisho t Pretreatment r utfall 1) Initial Wet Weather Phase During a two-month storm event the water level begins to rise above the top of the inlet pipe. This influent control feature reduces turbulence and avoids resuspension of pollutants. 2) Transition Phase As the inflow rate increases above the controlled-outflow rate, the tank fills and the floating contaminant layer accu- mulated from past storms rises. Swirling action increases at this stage, while sediment pile remains stable. 3) Full Capacity Phase When the high-flow outlet approaches full discharge, storm drains are flowing at peak capacity. The Vortechs System is designed to match your design storm flow and provide treat- ment throughout the range of storm events without bypass- ing. To accommodate very high flow rates, Vortechnics can assist desioners with confiaurina a peak-flow bvpass. 4) Storm Subsidence Phase/Cleaning Treated runoff is decanted at a controlled rate, restoring the water level to a low dry-weather volume and revealing a conical pile of sediment. The low water level facilitates inspection and cleaning, and significantly reduces maintenance casts. The system's central baffle prevents transfer of floatables to the outlet during cleaning or during the next storm. ormwaTer Treatment System The Vortechs Stormwater Treatment System, a major advancement in oil and grit separator technology, efficiently removes grit, contami- nated sediments, metals, hydrocarbons and floating contaminants from surface runoff. The Vortechs System's innovative design combines swirl-concentrator and flow-control technologies to optimize treatment efficiency. These features ensure effective capture of sediment and oils, and prevent resuspension of trapped pollutants - even at flow rates of up to 25 cfs. • Large system capacity provides an 80% net annual TSS removal rate • Installs below grade, minimizing land use • Custom-built of precast concrete near the job site 0 Low pump-out volume and one-point access reduce maintenance costs [] e Unique design prevents oils and other float- ables from escaping the system during cleanout "We have worked with Vortechnics on at least a dozen stormwater management plans for some of our largest corporate clients: Their efficient turnaround on our requests for technical support and CADD drawings has expedited the permitting process for our clients. We turn to Vortechnics when we need innovative stormwater solutions." - Lawrence Marsiglio. RE. Senior Civil Engineer, Barakos-Landino, Inc. Vortechs Systems may be used in a wide range of water-quality improvement applications, including: Wetlands/Waterfront Protection Retail Development Industrial Sites Municipal Improvements Commercial Development Transportation Facilities Existing Site Retrofits SECTION 02721 STORMWATER TREATMENT SYSTEM PART 1.00 GENERAL 1.01 DESCRIPTION *A. Work included: *n, m The Contractor, and/or a manufacturer selected by the Contractor and approved by the Engineer, shall furnish all labor, materials, equipment and incidentals * required and install all precast concrete stormwater'treatment systems and.. — appurtenances in accordance with the Drawings and these specifications. „ B. Related work described elsewhere: •* 1. Unit Masonry 2. Miscellaneous Metals 3. Waterproofing •s* 1.02 QUALITY CONTROL INSPECTION A. The quality of materials, the process of manufacture, and the finished sections shall be subject to inspection by the Engineer. Such inspection may be made at the place of manufacture, or on the work site after delivery, or at both places, and *" " the sections shall be subject to rejection at any time if material conditions fail to meet any of the specification requirements, even though sample sections may have been accepted as satisfactory at the place of manufacture. Sections « rejected after delivery to the site shall be marked for identification and shall be removed from the site at once. All sections which have been damaged beyond •• repair during delivery will be rejected and, if already installed, shall be repaired to ^ the Engineer's acceptance level, if permitted, or removed and replaced, entirely at the Contractor's expense. m B. All sections shall be inspected for general appearance, dimensions, soundness, * etc. The surface shall be dense, close textured and free of blisters, cracks, roughness and exposure of reinforcement. * C. Imperfections may be repaired, subject to the acceptance of the Engineer, after demonstration by the manufacturer that strong and permanent repairs result. Repairs shall be carefully inspected before final acceptance. Cement mortar m used for repairs shall have a minimum compressive strength of 4,000 psi at the end of 7 days and 5,000 psi at the end of 28 days when tested in 3 inch diameter by 6 inch long cylinders stored in the standard manner. Epoxy mortar may be utilized for repairs. 1.03 SUBMITTALS 4* A. Shop Drawings „ The Contractor shall be provided with dimensional drawings and, when specified, utilize these drawings as the basis for preparation of shop drawings showing ** details for construction, reinforcing, joints and any cast-in-place appurtenances. Shop drawings shall be annotated to indicate all materials to be used and all applicable standards for materials, required tests of materials and design « assumptions for structural analysis. Design calculations and shop drawings shall be certified by a Professional Engineer retained by the system manufacturer or * contractor and licensed in the state where the system is to be installed. Shop m drawings shall be prepared at a scale of not less than 1/4" per foot. Six (6) hard copies of said shop drawings shall be submitted to the Engineer for review and . approval. * B. Affidavit on patent infringement The Contractor shall submit to the Engineer, prior to installation of the stormwater * treatment system, an affidavit regarding patent infringement rights stating that any suit or claim against the Owner due to alleged infringement rights shall be ** defended by the Contractor who will bear all the costs, expenses and attorney's ^ fees incurred thereof. ™» PART 2.00 PRODUCTS &» 2.01 MATERIALS AND DESIGN « A. Concrete for precast stormwater treatment systems shall conform to ASTM C 857 and C 858 and meet the following additional requirements: *S» .* 1. The wall thickness shall not be less than 6 inches or as shown on the dimensional drawings. In all cases the wall thickness shall be no less than »» the minimum thickness necessary to sustain-HS20-44 loading requirements as determined by a Licensed Professional Engineer. „ 2. Sections shall have tongue and groove or ship-lap joints with a butyl mastic sealant conforming to ASTM C 990. m 3. Cement shall be Type 111 Portland cement conforming to ASTM C 150. m m 4. Pipe openings shall be sized to accept pipes of the specified size(s) and material(s), and shall be sealed by the Contractor with a hydraulic cement *» conforming to ASTM C 595M * 5. Internal metal components shall be aluminum alloy 5052-H32 in accordance with ASTM B 209. ** 6. Brick or masonry used to build the manhole frame to grade shall conform to ASTM C 32 or ASTM C 139 and the Masonry Section of these Specifications. \\MDI\SYS\DATA\VORTECHN\EMAIL\STDETAIL\VORTSPEC.DOC SECTION 02721 Page 2 7. Casting for manhole frames and covers shall be in accordance with The Miscellaneous Metals Section of these Specifications. 8. All sections shall be cured by an approved method. Sections shall not be shipped until the concrete has attained a compressive strength of 4,000 psi or util 5 days after fabrication and/or repair, whichever is the longer. 9. A butimen sealant in conformance with ASTM C 990 shall be utilized in affixing the aiuminum swiri chamber to the concrete vault. 2.02 PERFORMANCE Each stormwater treatment system shall adhere to the following performance specifications at the specified design flows, as listed below: Table 2.02 Vortechs Model 1000 2000 3000 4000 5000 7000 9000 11000 16000 Swirl Chamber Diameter (ft) 3.67 4 5 6 7 8 g 10 12 Design Treatment Capacity (cfs) 2.3 2.8 4.5 6.0 8.5 11.0 14.0 17.5 25.0 Sediment Storage (yd3) 1.00 1.25 1.75 2.50 3.25 4.00 4.75 5.50 7.00 Each stormwater treatment system shall include a circular aluminum "swirl chamber" (or "grit chamber") with a tangential inlet to induce a swirling flow pattern that will accumulate and store settleable solids in a manner and a location that will prevent re-suspension of previously captured particulates. Each swirl chamber diameter shall not be less than the diameter listed in Table 2.02 (neglecting chamber wall thickness). Each stormwater treatment system shall be of a hydraulic design that includes flow controls designed and certified by a professional engineer using accepted principles of fluid mechanics that raise the water surface inside the tank to a pre-determined level in order to prevent the re-entrainment of trapped floating contaminants. Each stormwater treatment system shall be capable of removing 80% of the net annual Total Suspended Solids (TSS). Individual stormwater treatment systems shall have the Design Treatment Capacity listed in Table 2.02, and shall not resuspend trapped sediments or re- entrain floating contaminants at flow rates up to and including the specified Design Treatment Capacity. Individual stormwater treatment systems shall have usable sediment storage capacity of not less than the corresponding volume listed in Table 2.02. The systems shall be designed such \\MDI\SYS\DATA\VORTECHN\EMAIUSTDETAIL\VORTSPEC.DOC SECTION 02721 Page3 that the pump-out volume is less than 1/z of the total system volume. The systems shall be designed to not allow surcharge of the upstream piping network during dry weather conditions. A water-lock feature shall be incorporated into the design of the stormwater treatment system to prevent the introduction of trapped oil and floatable contaminants to the downstream piping during routine maintenance and to ensure that no oil escapes the system during the ensuing rain event. Direct access shall be provided to the sediment and floatable contaminant storage chambers to facilitate maintenance. There shall be no appurtenances or restrictions within these chambers. The stormwater treatment system manufacturer shall furnish documentation which supports all product performance claims and features, storage capacities and maintenance requirements. Stormwater treatment systems shall be completely housed within one rectangular structure. 2.03 MANUFACTURER Each stormwater treatment system shall be of a type that has been installed and used successfully for a minimum of 5 years. The manufacturer of said system shall have been regularly engaged in the engineering design and production of systems for the physical treatment of stormwater runoff. Each stormwater treatment system shall be a Vortechs System as manufactured by Vortechnics, Inc., 41 Evergreen Drive, Portland, Maine 04103, phone: 207-878-3662, fax: 207-878-8507; and as protected under U.S. Patent # 5,759,415. PART 3.00 EXECUTION 3.01 INSTALLATION A. Each Stormwater Treatment System shall be constructed according to the sizes shown on the Drawings and as specified herein. Install at elevations and locations shown on the Drawings or as otherwise directed by the Engineer. B. Place the precast base unit on a granular subbase of minimum thickness of six inches after compaction or of greater thickness and compaction if specified elsewhere. The granular subbase shall be checked for level prior to setting and the precast base section of the trap shall be checked for level at all four corners after it is set. .If the slope from any comer to any other comer exceeds 0.5% the base section shall be removed and the granular subbase material re-leveled. C. Prior to setting subsequent sections place butimen sealant in conformance with ASTM C990-91 along the construction joint in the section that is already in place. D. After setting the base and wall or riser sections install the circular swirl chamber wall by bolting the swirl chamber to the side walls at the three (3) tangent points and at the 3-inch wide inlet tab using HILTI brand concrete anchors or equivalent 1/2-inch diameter by 2-3/4" minimum length at heights of approximately three inches (3") off the floor and at the mid-height of the completed trap (at locations of pre-drilled holes in aluminum cpmponents). Seal the bottom edge of the swirl \\MDI\SYS\DATA\VORTECHN\EMA1L\STDETAILWORTSPEC.DOC SECTION 02721 Page 4 chamber to the trap floor with the supplied aluminum angle flange. Adhere %" thick by 1" wide neoprene sponge material to the flange with half of it's width on the horizontal leg of the flange and half of it's width on the vertical leg. The aluminum angle flange shall be affixed to the floor with a minimum 3/8" diameter by 2-3/4" drop in wedge anchor at the location of the predrilled holes. Affix the swirl chamber to the flange with hex head %" x 1-1/2" zinc coated self- tapping screws at the location of the predrilled holes. Seal the vault sidewalls to the outside of the swirl chamber from the floor to the same height as the inlet pipe invert using butyi mastic or approved equal. E. Prior to setting the precast roof section, butimen sealant equal to ASTM C990 shall be placed along the top of the baffle wall, using more than, one layer of mastic if necessary, to a thickness at least one inch (1") greater than the nominal gap between the top of the baffle and the roof section. The nominal gap shall be determined either by field measurement or the shop drawings. After placement of the roof section has compressed the butyl mastic sealant in the gap, finish sealing the gap with an approved non-shrink grout on both sides of the gap using the butyl mastic as a backing material to which to apply the grout. Also apply non-shrink grout to the joints at the side edges of the baffle wall. F. After setting the precast roof section of the stormwater treatment system, set precast concrete manhole riser sections, to the height required to bring the cast iron manhole covers to grade, so that the sections are vertical and in true alignment with a 1/4 inch maximum tolerance allowed. Backfill in a careful manner, bringing the fill up in 6" lifts on all sides. If leaks appear, clean the inside joints and caulk with lead wool to the satisfaction of the Engineer. Precast sections shall be set in a manner that will result in a watertight joint, in all instances, installation of Stormwater Treatment Systems shall conform to ASTM specification C891 "Standard Practice For Installation of Underground Precast Utility Structures". G. Plug holes in the concrete sections made for handling or other purposes with a nonshrink grout or by using grout in combination with concrete plugs. H. Where holes must be cut in the precast sections to accommodate pipes, do all cutting before setting the sections in place to prevent any subsequent jarring which may loosen the mortar joints. The Contractor shall make all pipe connections. \\MDI\SYS\DATA\VORTECHN\EMAIL\STDETAIL\VORTSPEC.DOC SECTION 02721 Page 5 VI La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan CHAPTER 6 - SOURCE CONTROL BMPS 6.1 - Landscaping Manufactured slopes shall be landscaped with suitable ground cover or installed with an erosion control system. Homeowners will be educated as to the proper routine maintenance to landscaped areas including trimming, pruning, weeding, mowing, replacement or substitution of vegetation in ornamental and required landscapes. Per the RWQCB Order, the following landscaping activities are deemed unlawful and are thus prohibited: Discharges of sediment Discharges of pet waste Discharges of vegetative clippings Discharges of other landscaping or construction-related wastes. 6.2 - Urban Housekeeping Fertilizer applied by homeowners, in addition to organic matter such as leaves and lawn clippings, all result in nutrients in storm water runoff. Consumer use of excessive herbicide or pesticide contributes toxic chemicals to runoff. Homeowners will be educated as to the proper application of fertilizers and herbicides to lawns and gardens. The average household contains a wide variety of toxins such as oil/grease, antifreeze, paint, household cleaners and solvents. Homeowners will be educated as to the proper use, storage, and disposal of these potential storm water runoff contaminants. Per the RWQCB Order, the following housekeeping activities are deemed unlawful and are thus prohibited: Discharges of wash water from the cleaning or hosing of impervious surfaces including parking lots, streets, sidewalks, driveways, patios, plazas, and outdoor eating and drinking areas (landscape irrigation and lawn watering, as well as non-commercial washing of vehicles in residential zones, is exempt from this restriction.). Discharges of pool or fountain water containing chloride, biocides, or other chemicals. Discharges or runoff from material storage areas containing chemicals, fuels, grease, oil, or other hazardous materials. Discharges of food-related wastes (grease, food processing, trash bin wash water, etc.). DE:ad h:\reports\2352M51\finalswmpJ31.doc w.o.2352-151 10/4/2006 9:42 AM La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan 6.3 - Automobile Use Urban pollutants resulting from automobile use include oil, grease, antifreeze, hydraulic fluids, copper from brakes, and various fuels. Homeowners will be educated as to the proper use, storage, and disposal of these potential storm water contaminants. Per the RWQCB Order, the following automobile use activities are deemed unlawful and are thus prohibited: Discharges of wash water from the hosing or cleaning of gas stations, auto repair garages, or other types of automotive service facilities. - Discharges resulting from the cleaning, repair, or maintenance of any type of equipment, machinery, or facility including motor vehicles, cement-related equipment, port-a-potty servicing, etc. Discharges of wash water from mobile operations such as mobile automobile washing, steam cleaning, power washing, and carpet cleaning. The Homeowners Association will make all homeowners aware of the aforementioned RWQCB regulations through a homeowners' education program, samples of which are attached at the end of this chapter. 6.4 - integrated Pest Management (IPM) Principles Integrated pest management (IPM) is an ecosystem-based pollution prevention strategy that focuses on long-term prevention of pests or their damage through a combination of techniques such as biological control, habitation manipulation, modification of cultural practices, and use of resistant plant varieties. Pesticides are used only after monitoring indicates they are needed according to established guidelines. Pest control materials are selected and applied in a manner that minimizes risks to human health, beneficial and non-target organisms, and the environment. More information may be obtained at the UC Davis website (http://www.ipn.ucdavis.edU/WATER/U/index.html). IPM is achieved via the following: Common Areas: - Eliminate and/or reduce the need for pesticide use in the project design by: (1) Plant pest resistant or well-adapted plant varieties such as native plants. (2) Discouraging pests by modifying the site and landscape design. Home Owners: Educate homeowners on applicable pest resistant plants and native species and also encouraging onsite landscaping design. DE:ad h:\reportstf352\151\final swmp-01.doc w.o.2352-151 10/4/2006 9:42 AM La Costa Oaks North - Neighborhoods 3.1 , 3.3, 3.4 & 3.5 Storm Water Management Plan Pollution prevention is the primary "first line of defense" because pollutants that are never used do not have to be controlled or treated (methods which are inherently less efficient). - Distribute IPM educational materials to future site residents/tenants. Minimally, educational materials must address the following topics: (1) Keeping pests out of buildings and landscaping using barriers, screens and caulking. (2) Physical pest elimination techniques, such as, weeding, squashing, trapping, washing, or pruning out pests. (3) Relying on natural enemies to eat pests. (4) Proper use of pesticides as a last line of defense. 6.5 - Storm Water Conveyance Systems Stenciling and Signaqe The proposed development will incorporate concrete stamping, or equivalent, of all storm water conveyance system inlets and catch basins within the project area with prohibitive language (e.g., "No Dumping - I Live in «name receiving water»"), satisfactory to the City Engineer. Stamping may also be required in Spanish. 6.6 - Efficient Irrigation Practices All Home Owners' Association (HOA) maintained landscaped areas will include rain shutoff devices to prevent irrigation during and after precipitation. Flow reducers and shutoff valves triggered by pressure drop will be used to control water loss from broken sprinkler heads or lines. 6.7 - Trash Storage Areas All outdoor trash container areas shall meet the following requirements. A "trash containment area" refers to an area where a trash receptacle or receptacles are located for use as a repository for solid wastes. Design for such areas will include: - Paved with an impervious surface, designed not to allow run-on from adjoining areas, screened or walled to prevent off-site transport of trash. - Provide attached lids on all trash containers that exclude rain, roof or awning to minimize direct precipitation. DE:ad h:\reports\2352M51\finalswmp-01.doc w.o.2352-151 10/4/2006 9:42 AM NOT connected to sanitary sewer IPUfsystems and treatment plants? The primary purpose of storm drains is to carry rainwater away from developed areas to prevent flooding. Untreated storm water and the pollutants it carries flow directly into creeks, lagoons and the ocean. In'recent years, sources of water •pollution like industrial waters from factories have been greatly reduced. However, now the majority of water pollution occurs from things like cars leaking oil, fertilizers from farms and gardens, failing septic tanks, pet waste and residential car washing into the storm drains and into the ocean and pig:jyi/aterways. p*:p ;';AII these sources add up to a pollution SS^ilijjrbblem! But each of us can do our ll'partto help clean up our water and III that adds up to a pollution solution! I 1 :'; '•'•" . I • Car washing|'rj;hoto. is;used courtesy of the Water Quality Consortium, a • cooperative venturefe between theiWashington/:::; State Department;j6f;;;':';'•»'. Ecology, King:.Cpunty;andi:: 61* ••••?• ;.;::•:;'• .'0|j|;|||||||lrje:^Sto'rm Drain! the cities of Seattle and eyuey; acoma. ' «MM&r& **ift .' ' ':-:-/i.'- n City of Carlsfrad ;: 1635 Faraday Avenue Carlsbad qX 92008 Storm Water HOTIine: 760-602^ i99SIi I -'ftxAl'SiS,, , • ,."..'.r "'"iofline: :: '-.'•.V.^AV ': g ,- v, :::::/Vl-V Storm^/ater:HOTI ^^^^^^-"••"v,-^ 1 l^iB'o^^a «''' bi /'"•' -•.'';••••-.. • r-' , There's no problem with washing your "ajilt's just how and where you do it. /lost soap contains phosphates and ifier chemicals that harm fish and Mater quality. The soap, together with 'he dirt, metal and oil washed from our car, flows into nearby storm rains which run directly into lakes, |j||f.s or marine waters. J^lifyflpiphosphates from the soap can™S«i^af;i', i; :ause excess algae to grow. Algae lolbad, smell bad, and harm water ty. As algae decay, the process ||ffpp oxygen in the water that fish Having a clean environment -.':!.,is of primary importance for our health and economy, | ::;, Clean waterways provide ;;;:;;.v;cdrnrnercial opportunities, ,•'• recreation, fish habitat and x;;;;v add beauty to our ^landscape. YOU can help ••;: keep our ocean, creeks and tipi||ayopns clean by applying ^S':ii&the: following tips: ;.•;'•' ,; / '; -Use; soap sparingly. ., ; '|is||e a hose nozzle with a trigger to ;:, v: ;save water. :; • :: :; :^;;Bour your bucket of soapy water ";,;/;;:;,jj|lbwn the sink when you're done, not ;;;^- /iHrrtrie street. > /^ybid using engine and wheel ; ; - : cleaners or degreasers. ;'?:;. : ;Jake your car to a commercial car : I wash, especially if you plan to clean the engine or the bottom of your car. Most car washes reuse wash water several times before sending it to the sewer system for treatment. • Hire only mobile detail operators that will capture wash water and chemicals. It is unlawful for commercial vehicle washing operators to allow wash water to enter the storm drain system. you know that storm drains aressuKmFi"-ppcpnnected to sanitary sewer systems and treatment plants?SjsffiSij'ik-;vs>;.:..fjfjl|?primary purpose of storm drains j/H^tpiCarry rainwater away from 'eveloped areas to prevent flooding. ntreated storm water and the v; pollutants it carries, flow directly into /."creeks^ lagoons and the ocean. W'(ii"'i''fr;'i'!'!"'1'^'1'11'1MV@K 4 .isi} In .recent years, sources of water i?Mn.W K.,':- ' •; itipn like industrial waters from |f|c|5)rjes have been greatly reduced, fflowever now, the majority of water•.-,...) :|W'Hv.: |p||lutjpn occurs from things like cars "'eajqrjg oil, fertilizers from farms and g|f|lVns, failing septic tanks, pet ;:;waste and residential car washing into lie storm drains and into the ocean in|;waterways. ;j';|)ese sources add up to a pollution rpBjeml But each of us can do small js to help clean up our water and that adds up to a pollution solution! What's the problem with fertilizers and pesticides? Fertilizer isn't a problem—IF it's used carefully. If you use too much fertilizer or apply it at the wrong time, it can easily wash off your lawn or garden into storm drains and then flow untreated into lakes or streams. Just like in your garden, fertilizer in lagoons and streams makes plants grow. In water bodies, extra fertilizer can mean extra algae and aquatic plant growth. Too much algae harms water quality and makes boating, fishing and swimming unpleasant. As algae decay, they use up oxygen in the water that fish and other wildlife need. Fertilizer photo is used courtesy of the Water Quality Consortium, a cooperative venture between the Washington State Department of Ecology, King County and the cities of Bellevue, Seattle and Tacoma. Storm Water HOTIine: 760-602-2799 stormwater@ci.carlsbad.ca.us City of Carlsbad 1635 Faraday Avenue Carlsbad CA 92008 www.ci.carlsbad.ca.us ^Printed on recycled popor n •:•'; Hqwcan YQUfielp keesp the environment clean? llii|l^eanenvironmennsof "; '-primary .importance for our health and EfongJTiy. Clean waterways provide ommercial opportunities, recreation, ih• Habitat and add beauty to our 'jtjndscape. YOU can help keep our :reeHs;Jagoons and ocean clean byghlK-f!'.".applying the following tips: ?:li;• Don't blow or rake leaves and other waste into the street or gutter. Recycle yard waste or start your own ^compost pile. 'ijDpn't over irrigate. Use drip ;; irrigation, soaker hoses or micro- ,i;.spray system and water early in the ^morning. r If.you have a spray head sprinkler ?ystem, consider adjusting your tjlft'watering method to a cycle and 'Sfsoak. Instead of watering for 15 straight, break up the session into 5 minute intervals allowing water to soak in before the next application. Keep irrigation systems well- maintained and water only when needed to save money and prevent over-watering. Use fertilizers and pesticides sparingly. Have your soil tested to determine the nutrients needed to maintain a healthy lawn. Consider using organic fertilizers— they release nutrients more slowly. Leave mulched grass clippings on the lawn to act as a natural fertilizer. • Use pesticides only when absolutely necessary. Use the least toxic product intended to target a specific pest, such as insecticidal soaps, boric acid, etc. Always read the label and use only as directed. • Use predatory insects to control harmful pests when possible. • Properly dispose of unwanted pesticides and fertilizers at Household Hazardous Waste collection facilities. For more information on landscape irrigation, please call 760-438-2722. Master Gardeners San Diego County has a Master Gardener program through the University of California Cooperative Extension. Master Gardoners can provide good information, about dealing with specific pests and .; plants. You may call the Master, f,;. Gardener Hotline at 858-694:2860 or check out their website at j^'S'lt? www.masterqardenerssandieqo!6i:n;.-i" JK The hotline is staffed Monday—Friday, 9 am—3 pm, by experienced gardeners, who eire available to answer specific \ questions. Information from Master"^^ Gardoners is free to the public.'; :" ;';••'';'. jUn rnedip amfcj^rite|inr|piqes irnpor r Sabia usted que los desagues de luvia o alcantarillas no estan >n| ctadas al sistema de drenaje j$l|aiio.6 a las plantas de tratamiento iejag'ps negras? |fg|jci6n principal del desague 6 las ;ahtarillas es remover el agua de lluvia y i eyitarinundaciones. El agua que entra 'enJpsiidesagues va directamente a los ; arroyos, lagos y el oceano junto con la i;-';contgrriinaci6n depositada en las ; i^lcaiitarillas y las calles. istps dias la contaminacion del agua Iplcla directamente por fabricas e ]|u|irias se ha reducido jgnificantemente. Ahora la mayoria de la ;ontaminaci6n del agua origina de carros IB tiran ;aceite, el sobre uso de fertiljzantes para plantas, tanques : septicos danados, suciedad de animates y "ja'5|j§^ipe carros en zonas residenciales. Tpdps; estos contaminates se acumulan ||gil|pesagues 6 alcantarillados y son facarreados directamente al oceano uarido llueve. i)!|iin)a todos contribuimos a un gran problema de contaminacion. iPero cada uno de'nosotros puede hacer algo para 1]nr||a|!el agua y participar en la solution |!|3'::pbntaminaci6n! :; i,Cual es el problema creado por el uso de fertilizantes y pesticidas? El fertilizante no es un problema SI se usa con cuidado. Usar un exceso de fertilizante 6 en la temporada incorrecta resulta en el que el fertilizante se deslave con la lluvia y se vaya por el desague 6 alcantarillas a nuestros arroyos, lagos y el oceano. Los fertilizantes en nuestros lagos y arroyos hacen que las plantas crezcan, tal como en el jardin. Pero en el oceano el fertilizante causa que las algas y plantas acuaticas sobrecrezcan. Y el exceso de algas marinas pueden ser daninas a la calidad del agua y causar que la pesca, natacion y navegacion sean desagradables. Al echarse a perder las algas consumen el oxigeno del agua que los peces y otros animales necesitan para sobrevivir. La fotograffa al frente es cortesia del Consorcio de Calidad de Agua, en cooperacion con el Departamento Ecologico del Estado de Washington, el Condado de King, y las ciudades de Bellevue, Seattle yTacoma. r°' Protect Linea de Asistencia: 760-602-2799 stormwater@ci.carlsbad.ca.us Ciudad de Carlsbad 1635 Faraday Avenue Carlsbad CA 92008 www.ci.carlsbad.ca.us ^^^^^^W^^'^ , ' i •>.'.'• ^a^H if si jPfinled on recycled paper jUstedpiiede amildar "a hiantener nuestro:rnedip ambiente llm |rfer el medio ambiente limpio es pBpqrtante para nuestra salud y la iorpia. Conservar el agua limpia opprciona oportunidades para USDS jifciales, recreativos, habitat para es y aves, y agrega belleza a .uestro paisaje. Todos podemos ayudar a;manterier los arroyos, las lagunas, y el 'rialimpios sencillamente siguiendoKtnpMiivs' ' .estos conseps:iKMKfflS •";',.;.• . ™.*=.iarrer o usar maquinas *" sopjadoras no permita que las hojas ol y el cesped recien cortado entren en las alcantarillas o el ;Es preferible, convertir estos :desperdicios del jardin en abono. '--I - '.'"^iijiv.Llsar sistemas de irngacion de goteo i;i! ; yWas tecnicas de conservation del ':';• ••.agua son altamente recomendables. f,Ef preferible regar por la mafiana. ')'f jw'" • •• • | ,Xos sistemas de riego automatico son mas eficientes si se programan ;cgn' ciclos de cinco minutos y mas gcuentemente para que el agua edezca bien la tierra. Mantener los sistemas de irrigacion limpios y en buenas condiciones es importante para reducir el desperdicio del agua. Regar solamente cuando sea necesario reduce el uso del agua y ahorra dinero. Para mas information sobre sistemas de riego llame al 760-438-2722. Los pesticidas y fertilizantes deben usarse solamente cuando sea absolutamente necesario. Para mantener un pasto saludable se recomienda hacer un analisis de la tierra para determiner cuales fertilizantes aplicar y en que temporada. Es recomendable usar fertilizantes organicos en vez de productos quimicos. En ocasiones se puede dejar el sacate recien cortado sobre el pasto ya que actiia como un fertilizante natural. El uso de pesticidas debe ocurrir solo como ultimo recurso. Es preferible usar productos que sean bajos en toxicos, por ejemplo jabones insecticidas, acido borico, etc. Seguir las instrucciones en la etiqueta y usar el producto correctamente evita contaminar el agua de riego y lluvia. Cuando sea posible es preferible usar insectos predadores para controlar plagas. Los pesticidas y fertilizantes vencidos deben desecharse legalmente llevandolos a los centres de coleccibn de substancias toxicas localizados en varias ciudades del condado de San Diego. Llame al 760-602-2799 para obtener mas informacion. Master Gardeners El condado de San Diego y la Universidad '. ' de California Extensi6n Cooperative, lian' creado el programa de Master Gardener, . Los exfiertos de este programa estar|^;i;, disponibles para proporcionar informacion 1 sobre plantas y plagas. Usted pueder^' llamar <i la linea de Master Gardeners; ai. ! 858-694-2860 de lunes a viernes entre/ 9am y ;ipm para obtener respuestas a;sus preguntas. La pagina Internet www. V •.•_•.. masterdardenerssandleqo.orq es qtrp , recurso con informacion sobre estos ;' ,; :. >; .•'• ! temas. Esta informaci6n es totalmente gratis al publico. ;-:|B: Did you know that storm drains are NOT connected to sanitary sewer systems and treatment plants? The primary purpose of storm drains is to carry rainwater away from developed areas to prevent flooding. Untreated storm water and the pollutants it carries, flow directly into creeks, lagoons and the ocean. Jn recent years, sources of water pollution like industrial waters from factories have been greatly reduced. However now, the majority of water pollution occurs from things like cars leaking oil, fertilizers from farms, lawns and gardens, failing septic tanks, pet waste and residential car washing into the storm drains and into the ocean and waterways. All these sources add up to a pollution problem! But each of us can do small things to help clean up our water and that adds up to a pollution solution! Motor oil photo is used courtesy of the Water Quality Consortium, a cooperative venture between the Washington State Department of Ecology, King County and the cities of Bellevue, Seattle and Tacoma. Rain in the Storm Drain! City of Carlsbad Storm Water Protection Program City of Carlsbad 1635 Faraday Avenue Carlsbad CA 92008 Storm Water HOTIine: 760-602-2799 Funded by a grant from the California Integrated Waste • Management Board Q.nly RairOh tfr?;Stprm;Drain!.; ISKW HOTine: /» \ Printed on recycled paper t / : :;••' •:-' ;" I •.'.' .. ' :'!:"' ffl Oil does not dissolve in water. It lasts a long time and sticks to everything from beach sand to bird feathers. Oil and other petroleum products are toxic to people, wildlife and plants. One pint of oil can make a slick larger than a football field. Oil that § leaks from our cars onto roads and driveways is washed into storm : drains, and then usually flows - directly to a creek or lagoon and finally to the ocean. Used motor oil is the largest single .source of oil pollution in our ocean, creeks and lagoons. Americans spill • 180 million gallons of used oil each year into our waters. This is 16 times the . amount spilled by the Exxon Valdez in .Alaska. Having a clean environment : is of primary importance for our health and economy. : Clean waterways provide commercial opportunities, recreation, fish habitat and ; add beauty to our landscape. YOU can help : keep our ocean, creeks and 'lagoons clean by applying ,! the following tips: ;;?;?• Stop drips. Check for oil leaks regularly and fix them ^promptly. Keep your car tuned to ^reduce oil use. • Use ground cloths or drip pans ibeneath your vehicle if you have leaks ^or are doing engine work. M -Clean up spills immediately. ^Collect all used oil in containers with tight fitting lids. Do not mix different ;engine fluids. •When you change your oil, dispose of it properly. Never dispose of oil or other engine fluids down the storm drain, on the ground or into a ditch. • Recycle used motor oil. There are several locations in Carlsbad that accept used motor oil. For hours and locations, call 760-434-2980. • Buy recycled ("refined") motor oil to use in your car. ;./: ».•.•>,:•.:•>' '•-.:,;: J^:.-; j •.,;-....-. ;.*;«««;-jm;pprtanttpallof us! -5 Did you know that storm drains are 'V;''NOT connected to sanitary sewer : Xtsystems and treatment plants? The ' : primary purpose of storm drains is to CoParry rainwater away from developed :;;areas to prevent flooding. Untreated ;:;• storm water and the pollutants it ^'carries, flow directly into creeks, •^lagoons and the ocean. :n .-In recent years, sources of water 4: pollution like industrial waters from " factories have been greatly reduced, y- However now, the majority of water j^p^jiutjpn occurs from things like cars s;ir:leakjng:oil, fertilizers from farms and , failing septic tanks, pet waste '••"•:."residential car washing into thei ;..-•••• "storm-drains and into the ocean and 'i:/'-']f'"•('••'":'':p|p|waterways. ,li;these sources add up to a pollution.ii?;;)!;,.:•;•!;:'.pr6t3lem! But each of us can do small ../'..vkv"!' •"|Sr(p-tQ;.help clean up our water and •that;adds up to a pollution solution! SiP'•:l"i •;, Pet waste photo is used courtesy of the Water Quality Consortium, a. cooperative venture between the Washington State Department of Ecology, King County and the cities of Bellevue, Seattle and Tacoma. Storm Water HOTline: 760-602-2799 stormwater@ci.carlsbad.ca.us www.ci.carlsbad.ca.us f. jfcPrinted on recycled paper ',.:•- :7f-J|;f ,,V-^rii {• --1:' ' :',:•,'•"'••'.•'"(•'v^ -'''.; '•.•>.,<••'., ,;:'• ;: ./. ; 6; ,', ;SVC; ?.;; •:•• . f^hRe[waste is a health risk to pets and SSiK: .'':;.'•*: •'children. It's a if jjuisance;in our neighborhoods. Pet ;t<3 !s^;full of bacteria that can make SfiJ^rsSj-:;!••";,.•. _, .sipeople sick. This bacteria gets ras'lied'lntb'the storm drain and ends . vfpFi'""--:.?;Upin;our creeks, lagoons and ocean.\y,;ryyyyy;y;The bacteria ends up in shellfish living in these-water bodies. People whot'el'c':'');?'^" ••":'••• " at thpse/shellfish may get very sick.jsusyyy '•" -K ;:- .:;;:.-'. „ ^lilPJnary studies show that dog and $af wa?|e can contribute up to 25% of !t(ie: Haiimful bacteria found in our local 3e responsible and clean up after ourpets. It's as easy as 1—2—3! 1. Bring a bag. ll ;;:":ylilleaffiifup. ;3UDispose of waste &||properly in toilet or 1 ;.;'"•' Haying$ clean environment yy is of pjirnary importance for '•"••• Yyb'ur hea]th;:and economy. ;./.' :;:,: :;Glean wajerways provide .:.:, \commercjarppportunities, yrecreatiphj, fish habitat and •':£ add, beauty ..to our; ,• • • •;; ;•; :;•,-,•• • : -,, > -.;•.<!'•/ ' • • landscape. .YOU can help ••''.'. 'y keepipiirlcreeks, lagoons and:pcean,clean by : y;applying: the following tips: '.: '"••; .,• sGarfy'a plastic bag when ,;:;•, walking pets and be sure to pick up 'x-y;||||i;|em:y ;, :. . • "CJegn;up pet waste in your yard y-:- "Pic^up'after your pets before : cleaning patios, driveways and yothMhard surfaced areas. Never .ix Hose-pet waste into the street or The best way to dispose of pet waste is to flush it down the toilet because it gets treated by a sewage treatment plant. Other disposal methods for pet waste include sealing it in a bag and placing in trash or burying small quantities in your yard to decompose. Be sure to keep it away from vegetable gardens. --' . - -,. . -A. A Clean Environment is Important to All of Us! In the City of Carlsbad, storm drains flow directly into local creeks, lagoons and the ocean without treatment. Storm water pollution is a serious problem for our natural environment and for people who live near streams or wetlands. Storm water pollution comes from a variety of sources including oil, fuel, and fluids, from vehicles and heavy equipment, pesticide runoff from landscaping, and from materials such as concrete, mortar and soil from construction activities. The City of Carlsbad is committed to improving water quality and reducing the amount of pollutants that enter our precious waterways. Protec Storm Water Protection Program stormwater@ci.carlsbad.ca.us 760-602-2799 City of Carlsbad 1635 Faraday Avenue Carlsbad, CA 92008 £ Aprillled on recycled paper It's All Just Water, Isn't It? Although we enjoy the fun and relaxing times in them, the water used in swimming pools and spas can cause problems for our creeks, lagoons and the ocean if not disposed of properly. When you drain your swimming pool, fountain or spa to the street, the high concentrations of chlorine and other chemicals found in the water flows directly to our storm drains. bid you know that these storm drains are NOT connected to sanitary sewer systems and treatment plants? The primary purpose of storm drains is to carry rainwater away from developed areas to prevent flooding. Improperly disposing of swimming pool and spa water into storm drains may be harmful to the environment. Best Management Practices Best Management Practices or BMPs are procedures that help to prevent pollutants like chlorine and sediment from entering our storm drains. Each of us can do our part to keep storm water clean. Using BMPs adds up to a pollution solution! How Do I 6et Rid of Chbrine? Pool Filters Pool and spa water may be discharged to the storm drain if it has been properly dechlorinated and doesn't contain other chemicals. The good news is that chlorine naturally dissipates over time. Monitor and test for chlorine levels in the pool over a period of 3 to 5 days, brain the water before algae starts to grow. Consider hiring a professional pool service company to clean your pool, fountain, or spa and make sure they dispose of the water and solids properly. For more information about discharging wastewater to the sanitary sewer, please contact the Encina Wastewater Authority at (760)438- 3941. Before you discharge your swimming pool or spa water to the storm drain, the water: » Must not contain chlorine, hydrogen peroxide, acid, or any other chemicals. » Can not carry debris or vegetation. » Should have an acceptable pH of 7-8. » Can not contain algae or harmful bacteria (no "green" present). « Flow must be controlled so that it does not cause erosion problems. Clean filters over a lawn or other landscaped area where the discharge can be absorbed. Collect materials on filter cloth and dispose into the trash, Diatomaceous earth cannot be discharged into the street or storm drain systems, bry it out as much as possible, bag it in plastic and dispose, into the trash. Acid Washing Acid cleaning wash water is NOT allowed into the storm drains. Make sure acid washing is done in a proper and safe manner that is not harmful to people or the environment. It may be discharged into the sanitary sewer through a legal sewer connection after the pH has been adjusted to no lower than 5.5 and no higher than 11. Do the Job Plight! * Use the water for irrigation.Try draining de-chlorinated pool water gradually onto a landscaped area. Water discharged to landscape must not cross property lines and must not produce runoff. * Do not use copper-based algaecides. Control algae with chlorine or other alternatives to copper-based pool chemicals. Copper is harmful to the aquatic environment. « During pool construction, contain ALL materials and dispose of properly. Materials such as cement, (Sunite, mortar, and sediment munt not be discharged into the storm drains. VI La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan CHAPTER 7 - SITE DESIGN BMPS 7.1 - Site Design BMPs Priority projects, such as the La Costa Oaks North Neighborhoods 3.1, 3.3, 3.4 & 3.5 projects, shall be designed to minimize, to the maximum extent practicable the introduction of pollutants and conditions of concern that may result in significant impact, generated from site runoff to the storm water conveyance system. Site design components can significantly reduce the impact of a project on the environment. 7.2 - Minimize Impervious Footprint Methods of accomplishing this goal include: - Construct streets, sidewalks, and parking lots to the minimum widths necessary to be in accordance with standards set forth by the City of Carlsbad. 7.3 - Conserve Natural Areas The proposed La Costa Oaks North - Neighborhoods 3.1 & 3.3 - 3.5 developments have been mass graded and there is no natural area onsite. 7.4 - Permeable Pavements Site design BMP alternatives such as pervious pavements were also considered for use within the La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 project sites. However, the use of pervious pavements has several disadvantages such as: Porous pavement has a tendency to become clogged if improperly installed or maintained. Porous pavement has a high rate of structural failure. Anaerobic conditions may develop in underlying soils if the soil is unable to dry out between storm events. This may impede microbiological decomposition. Clay soils typically found within the project site are not sufficiently permeable to convey storm water runoff- leading to possible soil swelling and ultimately cracking of the pavement layer. These factors listed influenced the decision to not include pervious pavements within the site design. DE:ad h:\reports\2352M51\finalswmp-01.doc w.o.2352-151 10/4/2006 9:42 AM La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan 7.5 - Minimize Directly Connected Impervious Areas Methods of accomplishing this goal include: Draining rooftops into adjacent landscaping prior to discharging to the storm drain. These site design techniques will not be implemented within the La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 project sites. 7.6 - Slope & Channel Protection / Hillside Landscaping Methods of accomplishing this goal include: Planting native or drought tolerant vegetation on slopes. Energy dissipaters, such as riprap, at the outlets of new storm drains, culverts, conduits, or channels that enter unlined channels. 7.7 - Private Roads Per Section 3.2.3 of the City of Carlsbad SUSMP, the City of Carlsbad requires the implementation of at least one (1) of the following site design requirements for private roads: Rural swale system: Street sheet flows to vegetated swale or gravel shoulder, curbs at street corners, culverts under driveways and street crossings. Urban curb/swale system: Street slopes to curb, periodic swale inlets drain to vegetated swale/biofilter. Dual drainage system: Water quality design storm captured in street catch basins and discharged to adjacent vegetated swale or gravel shoulder, high flows connect directly to storm water conveyance system. The proposal of grass lined swales/biofilters lining the proposed private roads within the La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 project has been evaluated and has been deemed infeasible due to the following: Grass lined channels would be located beneath the grade level of the adjacent roads and side walks it serves to treat. However, water drained to these grassy channels would enter the existing clay type soils, causing possible swelling of the clay layers. This swelling will ultimately undermine the adjacent pervious surfaces (roads and sidewalks), causing cracking and failure of these surfaces. DE:ad hAreports\2352\151\finalswmp-01.doc w.o.2352-151 10/4/2006 9:42 AM VI La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan CHAPTER 8 - OPERATIONS & MAINTENANCE PLAN 8.1 - Maintenance Requirements Maintenance of the site BMPs will be the responsibility of the Homeowners Association. A maintenance plan will be developed and will include the following information: Specification of routine and non-routine maintenance activities to be performed A schedule for maintenance activities Name, qualifications, and contact information for the parties responsible for maintaining the BMPs For proper maintenance to be performed, the storm water treatment facility must be accessible to both maintenance personnel and their equipment and materials. 8.1.1 Vortechs Treatment Units Flow-based storm water treatment devices should be inspected periodically to assure their condition to treat anticipated runoff. Maintenance of the proposed Vortechnics units includes inspection and maintenance 1 to 4 times per year. Maintenance of the Vortechs units involves the use of a "vactor truck", which clears the grit chamber of the treatment unit by vacuuming all the grit, oil and grease, and water from the sump. Typically a 3-man crew is required to perform the maintenance of the treatment unit. Properly maintained Vortechs Systems will only require evacuation of the grit chamber portion of the system. In some cases, it may be necessary to pump out all chambers. In the event of cleaning other chambers, it is imperative that the grit chamber be drained first. Proper inspection includes a visual observation to ascertain whether the unit is functioning properly and measuring the amount of deposition in the unit. Floatables should be removed and sumps cleaned when the sump storage exceeds 85 percent of capacity specifically, or when the sediment depth has accumulated within 6 inches of the dry-weather water level. The rate at which the system collects pollutants will depend more heavily on site activities than the size of the unit. Maintenance of the site BMPs will be the responsibility of the Homeowners Association. A maintenance plan will be developed and will include the following information: Specification of routine and non-routine maintenance activities to be performed A schedule for maintenance activities Name, qualifications, and contact information for the parties responsible for maintaining the BMPs DE:ad h:\reports\2352\151\finalswnip-01.doc w.o.2352-151 KV4/2006 9:42 AM m La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan * <• For proper maintenance to be performed, the storm water treatment facility must be * accessible to both maintenance personnel and their equipment and materials. m The operational and maintenance needs of a Vortechs unit include: m Inspection of structural integrity and screen for damage. m Animal and vector control. " Periodic sediment removal to optimize performance. «Scheduled trash, debris and sediment removal to prevent obstruction. <• «" The facility will be inspected regularly and inspection visits will be completely documented: Preventive maintenance activities for a flow-based treatment unit are: m Trash and Debris Removal - trash and debris accumulation will be monitored during both the dry and wet season and after every large storm event (rainfall * events in excess of 1 inch). Trash and debris will be removed from the m Vortechs unit annually (at the end of the wet season). Trash and debris will also be removed when material accumulates to 85% of the unit's sump * capacity, or when the floating debris is 12 inches deep (whichever occurs first). ** Sediment Removal - sediment accumulation will be monitored during both the „ wet and dry season, and after every large storm (1.0 inch). Sediment will be removed from the Vortechs unit annually (at the end of the wet season). * Sediment will also be removed when material accumulates to 85% of the „ unit's sump capacity, or when the floating debris is 12 inches deep (whichever occurs first). Disposal of sediment will comply with applicable local, county, "* state or federal requirements. -w Corrective maintenance is required on an emergency or non-routine basis to correct problems and to restore the intended operation and safe function of a •* Vortechs unit. Corrective maintenance activities include: <m Removal of Debris and Sediment ••*• M Structural Repairs - Once deemed necessary, repairs to structural components of a Vortechs unit will be completed within 30 working days. * Qualified individuals (i.e., the manufacturer representatives) will conduct * repairs where structural damage has occurred. DE:ad h:\reports\2352\15t\flnal swmp-01.doc w.o.2352-151 10/4/2006 9:42 AM •m M * La Costa Oaks North - Neighborhoods 3.1, 3.3, 3.4 & 3.5 Storm Water Management Plan „ 8.2 - Operations and Maintenance Plan ** Target Maintenance Frequency - At a minimum, treatment unit should be cleaned „ annually. Maintenance Activity - Annual inspection and cleanout •• Clear grit chamber unit with vactor truck. m Perform visual inspection Remove floatables m m 8.3-Annual Operations & Maintenance Costs - The following costs are intended only to provide a magnitude of the costs involved in m maintaining BMPs. Funding shall be provided by the Master Home Owners Association for the La Costa Oaks North Neighborhoods 3.1 & 3.3 - 3.5.«• m Approximate annual maintenance costs for the proposed Vortechs unit are outlined below. Costs assume a 3 man crew: *w * Maintenance for Vortechs model 4000: Periodic Inspection, Maintenance and Monitoring = $800 - Annual Cleanout Cost = $1,250 Maintenance for Vortechs model 1000: «• Periodic Inspection, Maintenance and Monitoring = $800 Annual Cleanout Cost = $500 «• Maintenance for Vortechs model 2000:m * Periodic Inspection, Maintenance and Monitoring = $800 Annual Cleanout Cost = $750 ** Maintenance for Vortechs model 7000: Periodic Inspection, Maintenance and Monitoring = $800 Annual Cleanout Cost = $1,750 Subtotal = $1,250 + $500 + $750 + $1,750 = $4,250 - Contingency = $425 Total = $4,675 DE:ad h:\reports\2352M51\finalswTTip-01.doc w.o.2352-151 10/4/2006 9:42 AM