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Home My WebLink AboutCT 07-08; LA COSTA SPA & RESORT VILLAS; STORM WATER MANAGEMENT PLAN; 2008-12-03RL, -K- U I I I I I I I I I I I I I I I I I I I Storm Water Management Plan LA COSTA RESORT PLANNING AREA 1 - BUILDING 9A - 9B,10A -1 OE. CITY OF CARLSBAD SAN DIEGO COUNTY, CALIFORNIA (CT 07-08) SWMPOB-19 December 3, 2008 Prepared for W2007 La Costa I, LLC 2100 Costa Del Mar Road Carlsbad, CA 92009 CONTACT: Chevis Hosea, President Prepared by: RBF CONSULTING 5050 Avenida Encinas, Suite 260 Carlsbad, CA 92008 RM 0 103 . ... .. . 7604769193 CONSULTING1 Contact Person: fill ' / 'V Tim Thiele, P.E. 60 , . rn * RBF JN 55-100221.031 STORM WATER MANAGEMENT PLAN I i TABLE OF CONTENTS TABLE OF CONTENTS 1 I 1 2 PURPOSE AND SCOPE ..............................................................................2 PROJECT INFORMATION...........2 2.1 Project Description 2 2.2 .2 ' 3 Project Activities .................................. ................ ............................................. WATER QUALITY CONDITIONS OF CONCERN ...................................... 4 3.1 Potential Pollutants ............. .. ........................................................................... 4 3.2 Pollutants of Concern .......................................... ................. ........................ 6 I 3.3 4 Conditions of Concern .................................................................................7 POST-CONSTRUCTION BEST MANAGEMENT PRACTICE PLAN..........8 4.1 Site Design BMPs ............................................... . ........................................ 8 I 4.2 4.3 Source Control BMPs .......................................................................................9 BMPs for Individual Project Categories ............................... ......... .................. 12 4.4 Treatment Control BMPs ............................................................................. 13 I 4.5 5 Construction-Phase BMPs ..... ....................................... .................. . ........... LOW IMPACT DEVELOPMENT ........................ .......... .............................. 16 16 5.1 Pervious Pavement ...................... ............ ...................... ........... . ........................ 16 I 5.2 5.3 Roof Runoff Disconnect Parking Lot Filter Strips ............. .......................... .......................................... 16 16 6 MAINTENANCE ............................ ................................................................ ..17 I TABLE OF FIGURES Figure2-1 Vicinity Map .....................................................................................................3 Figure 4-1 Kristar Floguard Plus® Inlet Insert 15 LIST OF TABLES Table 3-1 Anticipated and potential pollutants by project type (San Diego County, 2008) ............................................................................................................4 I Table 3-2 Table 4-1 Summary of 303(d) impairments of downsteam water Iodies 7 Site design BMPs alternatives .............. . .......................................................... 8 Table 4-2 Source-control BMP alternatives .................... ............. .................................. 9 Table 4-3 Carlsbad SUSMP Individual Project Categories ... . .................................... 12 I Table 4-4 Treatment Control BMP Selection Matrix (San Diego County, 2008).........13 Table 4-5 Treatment-Control BMP alternatives 14 I APPENDIX A STORM WATER REQUIREMENTS APPLICABILITY CHECKLIST B BMP CALCULATIONS AND FACT SHEETS C BMP SITE PLAN :• I D APPROVED STORM WATER MANAGEMENT PLAN I La Costa Resort Planning Area 1, Building 9A-9B, bA-10E 1 Storm Water Management Plan : STORM WATER MANAGEMENT PLAN I 1 PURPOSE AND SCOPE I This report is a site-specific storm water management plan that supplements the approved Master Storm Water Management Plan prepared by Rick Engineering, dated October 29, 2003. Presented within this document are the water quality measures I required for the development of Planning Area #1 - Building 9A, 9B, bA-10E at the La Costa Resort and Spa, in order to fulfill the requirements of the City of Carlsbad. This report also describes the implementation and maintenance of water quality Best- Management Practices that will be installed on the site. I 2 PROJECT INFORMATION Project Description I 2.1. The project is located within théOity of Carlsbad at the La Costa Resort and Spa (CT- 07-08). The campus is bound by El Camino Real to the west, Arenal Road to the north, I and San Marcos Creek to the south. Planning Area 1 is located at the southeast corner of Arenal Road and Estrella De Mar Road (see Figure 2-1). Existing site conditions include two paved parking lots (0.55 acre and 1.29 acre). There I is an existing building and associated landscaping area within the project site. The site is located approximately 2,000 feet from the San Marcos Creek. The project site contains side slopes of 2:1 or less. The project is not located within the Coastal Zone. Its I land use designation is Travel/Recreation Commercial. There are no sanitary landfills, historical, archaeological or paleontological resources located within a half-mile of the project site. I 2.2 Project Activities I The project consists of seven, two and three story, commercial dwelling unit buildings both attached and detached (37,090 sq. ft., including balconies and common area) and an adjacent parking lot (54,400 sq. ft.). Landscaping will be incorporated into the planter I medians and at the perimeter of building and each lot. There is one private driveway proposed as part of this project. The driveway will provide access to the site from Estrella De Mar Road. Drainage from the project will be directed into a proposed storm drain system and connected to an existing piping system that will ultimately outlet to the I San Marcos Creek located at the southerly boundary of the La Costa Resort campus. Approximately 90% of the site will be re-graded as part of this project. I The project is considered a high priority project by the City of Carlsbad (See Appendix A - "Storm Water Requirements Applicability Checklist"). Therefore, the project will I incorporate all applicable permanent storm water management requirements. These include the site design and source control BMPs, BMPs applicable to individual priority project categories, and treatment control BMP requirements. I I La Costa Resort Planning Area 1, Building 9A-9B, 1A-1E : 2 Storm Water Management Plan : STORM WATER MANAGEME\IT PLA\ . .-.. L. 147 I ft LI : Lj ._-• 3 . Aw jWJ,LJ I E i SITE . ., 1 £ A k DD5Th ------ as Bros Mir s Figure 2-1 Vicinity Map (Reference Thomas Bros. 1127,1147) La Costa Resort Planning Area 1. Building A-98, 1 OA- 1 OC 3 Storm Water Managemen Plan 11:. STORM WATER MANAGEMENT PLAN 1 3 WATER QUALITY CONDITIONS OF CONCERN 1 3.1 Potential Pollutants The proposed project is not expected to generate significant amounts of pollutants, but I many constituents are generally anticipated for projects in this category (Table 3-1). Table 3.1 Anticipated and potential pollutants by project type (Son Diego County, 2002a). 'V Anticipated Pollutants General Pollutant Categories P Potential Pollutants .. .L) a -a 3 Priority Project Categories - -a a 2 .. .. a E 0: 0 O ..a E a, 0 "-' a C a, E .tt c . LD > 2 a aC C ........ 5 (f) . Z g I 0 ... I-0 0 a M a, Q Detached Residential Attached Residential I I I p(l) p(2) p 1 Commercial (>100,000 sf) p(i) p(i) p(2) ( p(5) I P(3) P(5) Auto Repair Shops I I(4)() I I Restaurants Hillside Development (>5,000 sf) I I I I I I Parking Lots p(l) p)l) I I Pt" I pCi) Streets, Highways, and Freeways I p)i) I p(4) I p(a) I A potential pollutant if landscaping exists on-site; A potential pollutant lithe project includes uncovered parking areas; A potential pollutant if land use involved food or animal waste products; Including petroleum hydrocarbons; Including solvents As indicated in Section 2.2, the project consists of two commercial dwelling building totaling 22,740 square feet; five detached commercial dwelling unit buildings totaling 14,350 square feet; and 54,400 sq. ft. of associated parking lot area (See Site Map), thus the project falls into the Parking Lot and Attached Residential priority project category, as indicated in Table 3-1. Potential pollutants of concern associated with this priority project category include: :. Sediments (since there will be landscaped areas on site); Nutrients (since there will be landscaped areas on site); La Costa Resort Planning Area 1, Building 9A-9B, bA-bE . 4..... Storm Water Management Plan .1 I I I I I I Li I Li I I I I I I STORM WATER MANAGEMENT PLAN I . Metals (associated with vehicle parking); . : : •. : •. :. Litter and trash collecting in the drainage systems; . Oxygen-demanding substances including biodegradable organic material and I . chemicals; :. ...... ...... . . ... + Oils, grease, and other hydrocarbons emanating from paved areas on the site; I Pesticides Bacteria and viruses resulting from the presence of organic wastes; and used to control nuisance growth 31.1 Sediment I Sediments are 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, lower young aquatic organisms survival rates, smother I bottom dwelling organisms, and suppress aquatic vegetation growth. I 3 1 2 Nutrients Nutrients are inorganic substances,: such as nitrogen and phosphorus. . They commonly exist in the form of mineral salts that are either dissolved or suspended in water. Primary I 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. I 3.1.3 Metals Metals are raw material:: components in non-metal products such as fuels, adhesives, paints, and other coatings. The primary sources of metal pollution in storm water are I typically commercially available metals and metal products. Metals of concern include cadmium, chromium, copper,: lead, mercury, and zinc. Lead and chromium have been used as corrosion inhibitors in primer coatings and cooling tower systems. At low I concentrations naturally occurring in soil, metals are not toxic. However, at higher concentrations, certain metals can be toxic to aquatic life. Humans can be impacted from contaminated groundwater resources, and bioaccumulation of metals in fish and shellfish. Environmental concerns, regarding the potential for release of metals to the I environment, have already led to restricted metal usage in certain applications I 3.1.4 Trash and Debris Trash (such as paper, plastic, polystyrene packing foam, and aluminum materials) and biodegradable organic matter (such as leaves, grass cuttings, and food waste) are I general waste products on the landscape. The presence of trash and debris 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 I lower its water quality. Also,: in areas where stagnant water exists, 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 I hydrogen sulfide I La Costa Resort • •::: • • .: .....• Planning Area 1, Building 9A-9B, bA- bE .: . • 5.......:1 . Storm Water Management Plan •. • . • ...• .: STORM WATER MANAGEMENT PLAN I 3.1.5 Oxygen-Demanding Substances This category includes biodegradable organic material as well as chemicals that react I with dissolved oxygen in water to form other compounds. Proteins, carbohydrates, and fats are examples of biodegradable organic compounds. Compounds such as ammonia and hydrogen sulfide are examples of oxygen-demanding compounds. The oxygen I demand of a substance can lead to depletion of dissolved oxygen in a water body and possibly the development of septic conditions 1 3.1.6 Oil and Grease Oil and grease are characterized as high-molecular weight organic compounds. The I primary sources of oil and grease are petroleum hydrocarbon products, motor products from leaking vehicles, esters, oils, fats, waxes, and high molecular-weight fatty acids. Introduction of these pollutants to the water bodies are very possible due to the wide uses and applications of some of these products in municipal, residential, commercial, 1 industrial, and construction areas. Elevated oil and grease content can decrease the aesthetic value of the water body, as well as the water quality. 1 3.1.7 Bacteria and Viruses Bacteria and viruses are ubiquitous microorganisms that thrive under certain environmental conditions. Their proliferation is typically caused by the transport of I animal 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 I growth and aquatic life. Also, the decomposition of excess organic waste causes increased of undesirable organisms in the water. I 3.1.8 Pesticides Pesticides (including herbicides) are chemical compounds commonly used to control nuisance growth of organisms.. Excessive application of a pesticide may result in runoff I containing toxic levels of its active component. 1 3.2 Pollutants of Concern The Environmental Protection Agency (EPA) is the primary federal agency responsible for management of water quality in the United States. The Clean Water Act (CWA) is I the federal law that governs water quality control activities initiated by the EPA and others. Section 303 of the CWA requires the adoption of water quality standards for all I surface water in the United States. Under Section 303(d), individual states are required to develop lists of water bodies that do not meet water quality objectives after required levels of treatment by point source dischargers. Total maximum daily loads (TMDL5) for all pollutants for which these water bodies are listed must be developed in order to bring I them into compliance with water quality objectives. The project is located within the San Marcos hydrologic area of the Carlsbad hydrologic I unit. Receiving waters for the project site include the San Marcos Creek, the Batiquitos Lagoon and ultimately the Pacific Ocean. I La Costa Resort Planning Area 1, Building 9A-9B, 10A-1:0E 6...... . Storm Water Management Plan : . STORM WATER MANAGEMENT PLAN Table 3-2 summarizes the receiving waters and their classification by the RWQCB Region 9 Hydrologic Approximate 303(d) Receiving Water Distance Unit Code From Site Impairment(s) Pacific Ocean Shoreline— San Marcos HA 904.50 2.5 mi Bacteria Indicators Batiguitos Lagoon - San Marcos HA 904 51 0.5 mi None San Marcos Creek - San Marcos HA 904 51 2,000 Sediment Toxicitv The primary pollutants of concern are sediment toxicity and phosphorus. Secondary pollutants of concern are metals trash and debris, oxygen demanding substances, oil and grease, bacteria and viruses, and pesticides. 3.3 Conditions of Concern According to the City of Carlsbad SUSMP, a change to a priority project site's hydrologic regime would be considered a condition of concern if the change would impact downstream channels and habitat integrity. However, the changes in hydrologic characteristics resulting from the development of this site have already been incorporated into the downstream storm drain system design. Additionally, the hydrologic regime described here will not be negatively impacted with the proposed project. Previously, Planning Area 1 existed as a paved roadway with several large homes, and was largely impervious. The revised site plan proposes a similar land use with comparable runoff values. Runoff from Planning Area 1 will discharge into an existing 18-inch storm drain located within Estrella De Mar Road. The existing storm water drains via the campus system to a diversion structure located just downstream of a CDS unit. The diversion structure initially directs water to the 36-inch, recently slip-lined CMP, beneath El Camino Real and as flows increase, water is split with some flow being diverted to San Marcos Creek. Storm water, that drains via the existing 36-inch drain line beneath El Camino Real discharges directly into an open area at the east end of Batiquitos Lagoon. There is no defined channel at this location for sediment to be created and transported. Storm water that drains via the 30-inch storm drain (which ultimately is planned to be upsized to a 42- inch RCP) discharges into San Marcos Creek, just upstream of El Camino Real. Downstream of this location the Creek is stable, showing no erosion. A separate drainage report (Drainage Study for La Costa Resort & Spa, prepared by Hunsaker & Associates, dated September 15, 2006) has been prepared to support the design of the existing storm drain system. This study assumed ultimate conditions at 100% build out for the La Costa Resort & Spa campus when determining pipe sizes and impacts to downstream facilities. The Hydrology and Hydraulics report prepared by RBF Consulting and submitted for Planning Area 1 analyzes the revised site layout to be sure the new design does not exceed the runoff estimates calculated within the 2006 Hunsaker Report. The Hydrology and Hydraulics Report prepared by RBF Consulting for Planning Area 1 concludes that the existing storm drain system will not be adversely impacted by the revised building layout. The integrity of downstream channels and existing habitats will also be maintained. Since runoff from the project discharges into new and existing La Costa Resort : Planning Area 1, Building 9A-9B, bA-10E 7 : Storm Water Management Plan I I I I I I 1 I El I I I I I I I I I I I I I I I I I I I I I I I I I I I I I U I I I I I I I I I I I I I I I I I R STORM WATER MANAGEMENT PLAN 4 POST-CONSTRUCTION BEST MANAGEMENT PRACTICE PLAN The project site incorporates four major types of post-construction best management practices (BMPs). These types are (1) site design BMPs; (2) source control BMPs; (3) site design and source control BMPs for individual priority project categories; and (4) treatment control BMPs. In general, site design BMPs and source control BMPs reduce the amount of storm water and potential pollutants emanating from a site and focus on pollution prevention. Treatment-control BM Ps target anticipated potential storm water pollutants. The project will apply these BMPs to the maximum extent practicable. 4.1 Site Design BMPs Site design BMPs aim to conserve natural areas and minimize impervious cover, especially impervious areas 'directly connected' to receiving waters, in order to maintain or reduce increases in peak flow velocities from the project site. The U.S. EPA has listed several site design BMPs that can be implemented in development projects. The project has incorporated site design BMPs to the maximum extent practicable. Table 4- 1 lists site-design BMP alternatives and indicates the practices that have been applied to the project site. : Table 4-1 Site design BMPs alternatives O Alternative Payers Low Impact Development (LID) El Alternative Turnarounds D Narrower Residential Streets El Conservation Easements 0 Open Space Design El Development Districts 0 Protection of Natural Features Z Eliminating Curbs and Gutters Z Redevelopment Z Green Parking 0 Riparian/Forested Buffer 0 Green Roofs El Urban Forestry El Infrastructure Planning El Street Design and Patterns El Other (Explained Below) 4.1.1 Eliminating Curbs and Gutters Site runoff in the parking lot area will be directed into natural swales located in median islands. Zero-inch high curb will be used to allow flow to enter the swales. 4.1.2 Green Parking Approximately 15% of the parking lot area will be constructed with pervious pavement. Additionally, natural swales will be located in median islands to help treat parking lot runoff. 4.1.3 Redevelopment The proposed development will replace the existing paved parking lot with the "Green" parking described in Section 4.1.2. La Costa Resort Planning Areal, Building 9A-9B, bA-10E 9 Storm Water Management Plan PF I I I I I I I I I I I I I I I I 1 I I STORM WATER MANAGEMENT PLAN Low Impact Development (LID) is an alternative method of land development that seeks to maintain the natural hydrologic character, of the site. Per the Draft County of San Diego Low Impact Development Handbook and in anticipation for the future City of Carlsbad Municipal Permit LID requirement, LID BMPs have been included as part of our site design. LID BMPs will collectively minimize directly connected impervious areas and promote infiltration. Refer to Section 5 for a description of the LID practices proposed for this project. 42 Source Control BMPs Source-control BMPs are activities, practices, and procedures (primarily non-structural) that are designed to prevent urban runoff pollution. These measures either reduce the amount of runoff from the site or prevent contact between potential pollutants and storm water. In addition, source-control BMPs are often the best method to address non-storrr (dry-weather) flows. The California Stormwater Quality Association (CASQA) "BMP Handbook for New Development and Redevelopment" (January 2003) has listed severa source-control BMPs that can be implemented in development projects. Table 4-2 lists source-control BMP alternatives and indicates the practices that will be applied at the project site. Table 4-2 Source-control BMP alternatives. Z SD-10: Site Design and Landscape Planning Li SD-30: Fueling Areas Li SD-1 1: Roof Runoff Controls : : LI SD-31: Maintenance Bays and Docks 0 SD- i 2: Efficient Irrigation 0 SD-32: Trash Storage Areas SD 13 Storm Drain System Signs Li SD 33 Vehicle Washing Areas SD-20: Pervious Pavements 0 SD-34: Outdoor Material Storage Areas 0 SD-21: Alternative Building Materials:.: 0 SD-35: Outdoor Work Areas LI Other, (Explained Below) 0 SD 36 Outdoor Processing Areas 4.2.1 Site Design and Landscape Planning Efficient landscape design can be an effective source-control to prevent pollution ir storm water and dry-weather flows. The completed project will implement principles o runoff-minimizing landscape design and an effective landscape maintenance plan to th maximum extent practicable 4.2.1.1.. Runoff-Minimizing Landscape Design Landscape designs that group plants with similar water requirements can reduce excest irrigation runoff and promote surface infiltration. Landscape designs should utilize non invasive native plant species and plants with low water requirements when possible. The Resort takes abundant advantage of planting pots for various classes and sizes of plants Potted plants are efficient for water conservation La Costa Resort Planning Area 1, Building 9A-9B, bA-bE Storm Water Management Plan STORM WATER MANAGEMENT PLAN 4.2.1.2 Landscape Maintenance The landscape maintenance plan should include a regular sweeping program of impervious surfaces, litter pick-up, and proper equipment maintenance (preferably off- site), and proper use of chemicals to help eliminate scurces of storm water pollutants. Common elements of an effective landscape maintenance plan include: A regularly rotating schedule of maintenance ensures the property is in a perpetual state of good cleanliness. Maintenance obligations include regular sweeping of sidewalks, driveways, and gutters, and staff members' job duties include perpetual litter pick-up. Also, if necessary, the resort provides convenient trash receptacles for public use located throughout the property. :. Avoid using water to clean sidewalks, driveways, and other areas. :• All landscape maintenance equipment is cleaned in an isolated area within the maintenance yard located offsite at the south end of the campus. Minimize water use and do not use soaps or chemicals. A commercial wash-rack facility is to be used whenever possible Keep all landscape equipment in good working order. Fix all leaks promptly, and use drip pans/drip cloths when draining and replacing fluids. Perform all repairs and equipment maintenance in the maintenance yard located on the south side of the campus. Protect all nearby storm water inlets. Keep regular logs of major equipment repairs. All spent fluids are to be collected and disposed of properly. :• Materials with the potential to pollute runoff (soil, pesticides, herbicides, fertilizers, detergents, petroleum products, and other materials) are handled, delivered, applied, and disposed of with care following manufacturer's labeled directions and in accordance with all applicable Federal, state, and local regulations. Volatile chemicals are stored and locked in isolated storage sheds with paved flooring. + Pesticides and fertilizers, if used, will be applied according to manufacturer's directions and will not be applied prior to a forecast rain event. Any material broadcast onto paved surfaces (e.g. parking areas or sidewalks) will be promptly swept up and properly disposed. 4.2.2 Efficient Irrigation The completed project will implement principles of common-area efficient irrigation. Automatic irrigation systems should include water selsors, programmable irrigation timers, automatic valves to shut-oft water in case of :apid pressure drop (indicating possible water leaks), or other measures to ensure the efficient application of water to the landscape and prevent unnecessary runoff from irrigation. Drip irrigation and other low-water irrigation methods should be considered where feasible. Common elements of efficient irrigation programs include: + Reset irrigation controllers according to seasonal needs. Do not over-water landscape plants or lawns. La costa Resort Planning Areal, Building 9A-9B, bA-10E 11 Storm Water Management Plan I I I I I I I I 11 I I I I I I I I I I STORM WATER MANAGEMENT PLAN Keep irrigation equipment in good working condition Promptly repair all water leaks 4.2.3 Material and Trash Storage Area Design There is no outdoor material storage area associated with the proposed project. For Buildings 9A and 9B the trash storage area is located on the first floor. Chutes are located on upper levels. Trash is regularly collected from the storage area for disposal. For Buildings 1OA-10E, housekeeping regularly removes trash from rooms and disposes it directly into covered Resort containers 4.2.4 Pollution Prevention Outreach for Owners and Guests One source-control best management practice for commercial sites is pollution prevention outreach. For instance, at the lease signing or as part of the lease, the tenant can be presented with a brochure to encourage them to develop and implement a pollution prevention program. The pollution prevention program would emphasize source reduction, reuse and recycling, and energy recovery. Hotel guests are also encouraged to support pollution prevention; recycling containers are located regularly throughout the Resort. Also, the Resort kindly offers guests the opportunity to reuse towels, where appropriate, tohelp relieve the burden on municipal water use. The following offer suggestions for measures to be included in these areas of pollution prevention. The pollution prevention outreach should choose the measures most applicable to the project site for the project site. 4.2.4.1 Source Reduction :. Incorporating environmental considerations into the designing of products, buildings, and manufacturing systems enables them to be more resource efficient :• Rethinking daily operations and maintenance activities can help industries eliminate wasteful management practices that increase costs and cause pollution. Controlling the amount of water used in cleaning or manufacturing can produce less wastewater. S Re-engineering and redesigning a facility or certain operation can take advantage of newer, cleaner and more efficient process equipment. Buying the correct amount of raw material will decrease the amount of excess materials that are discarded (for example, paints that have a specified shelf life) 4.2.4.2 Reuse/Recycling + Using alternative materials for cleaning, coating, lubrication, and other production processes can provide equivalent results while preventing costly hazardous waste generation, air emissions, and worker health risks. :• Using "green" products decreases the use of harmful or toxic chemicals (and are more energy efficient than other products). La Costa Resort Planning Area 1, Building 9A-9B, bA-bE 12 Storm Water Management Plan :. I I 1 I I I I I I I I I I I I 1 I I I STORM WATER MANAGEMENT PLAN I •:. One company's waste may be another company's raw materials. Finding markets for waste can reduce solid waste, lessen consumption of virgin resources, increase I income for sellers, and provide an economical resource supply for the buyers. 4.2.4.3 Energy Recovery I •:. Using energy, water, and other production inputs more efficiently keeps air and water clean, reduces emissions of greenhouse gases, cuts operating costs, and improves i productivity. I 4.2 .5 Storm Drain Signage All new storm drain grate inlets constructed as part of this project will be signed with the message "No Dumping - Drains to Oceans" or equivalent message as directed by the I City. I 4.2.6 Pervious Pavement Pervious paving will be used in..approximately 15% of the parking lot area. This is a system comprising a load-bearing, durable surface together with an underlying layered I structure that temporarily stores water prior to infiltration and/or drainage to a grate inlet 1 4.2 .7 Integrated Pest Management Program An Integrated Pest Management Program (IPM) will be implemented as part of the storm water management plan. The IPM will use pest and environmental information with I available pest control methods to prevent unacceptable levels of pest damage by the most economical means and with the least possible hazard to people, property, and the I environment. Methods may include regular trash collection, in addition to regular inspection of the storm drain pipe/swale system to prevent extended periods of standing water. 1 43 BMPs for Individual Project Categories I be The City of Carlsbad SUSMP lists ten individual project categories for which BMPs must provided. Table 4-3 below lists these individual project categories and indicates that the individual category of parking areas is applicable to the proposed project. Inlets equipped with filter inserts treat any runoff generated and additional treatment is I provided as discussed in Section. 4.4. Slopes will be vegetated to provide permanent stabilization and to prevent erosion. Table 4-3 Carlsbad SUSMP Individual Project Categories Private Roads I D O Residential Driveways & Guest Parking 0 Dock Areas Mat Bays. . . I 0 La Costa Resort Planning Areal, Building 9A-9B, 1OA-10E 13 Storm Water Management Plan . . I I I I I I I I I I I I I I I I I 1 I STORM WATER MANAGEMENT PLAN o Vehicle Wash Areas .1 El Outdoor Processing Areas El Equipment Wash Areas Parking Areas : OFuelingArea : 0 Hillside Landscaping H. I 4.4 Treatment Control BMPs Post-construction "treatment control" storm water management BMPs provide treatment for storm wa:er emanating from the project site. Structural BMPs are an integ:al element of post-construction storm water management and may include stoWage, f:ltration, and infiltration practices. BMPs have varying degrees of effectiveness verses different pollutants of concern. Table 4-4 below summarizes which treatment control BMPs and removal effectiveness for certain constituents. Table 4-4 Treatment Control BMP Selection Matrix Treatment Control BMP Cagories O High Removal Efficiency Medii.rr Removal Efficiency Low Removal Efficiency . • . . - C,) • L . C u_. . C .2 . .2 C C 0. Pollutant of Concern . . . . 2 Co - . (I) • Sediment ••. . . .... 0 0 0.. 0 0 0 0 Nutrients • e 0 I • • Heavy Metals . : ... . 0 0 0 0 e I Organic Compcunds .. . 0 0 0 0 0 . Trash & Debris : 0 0 0 0 0 0 0 Oxygen Demanding Substances . 0 0 0 0 0 e I Bacteria and viruses • • 0 0 0 0 0 e I Oils and Grease • 0 0 0 0 0 e I Pesticides . 0 0 0 0 0 e I Original Sources: County of San Diego Model SUSMP, Requirements for Development Applications (DRAFT June 12, 2008) La Costa Resort I • • . . . • • Planning Area 1 Building 9A-9B, 1OA-1OE 14 . Storm Water Management Plan • . • . • • ..... . STORM WATER MANAGEMENT PLAN 1 I 4.4.1 Treatment Control BMP Selection The selection, design and location of structural BMPs for Planning Area 1 depend largely I on the project-wide drainage plan and previously approved Master Storm Water Management Plan, prepared by Rick Engineering, dated October 29, 2003. BMP alternatives were evaluated for their relative effectiveness for treating potential pollutants from the project site; technical feasibility; relative costs and benefits; and applicable I legal, institutional, and other constraints. Table 4-5 below lists treatment-control BMP alternatives and identifies the BMPs selected for the project site. Treatment Control BMPs function. to mitigate pollutants of concern anticipated from project activities. Receiving waters downstream of the project site are impaired for I bacterial indicators, DDE (an organic substance), Phosphorus (a nutrient) and sediment toxicity, as shown in Table 3-2. The proposed project activities are anticipated to produce sediment, nutrients, trash, oxygen demanding substances, oil & grease, and pesticides, as shown in Table 3-1. Therefore, the primary pollutants of concern I associated with the project are bacteria, nutrients, and sediment. The remaining anticipated pollutants are considered secondary pollutants of concern. Treatment control BMPs for this project were chosen to treat the primary pollutants of concern at a I "high removal efficiency", and treat secondary pollutants of concern at no less than a "low removal efficiency", as shown in Table 4-4. Table 4-5 Treatment BMP -Control alternatives. I Vegetated Swales and/or Strips, [I Wet Ponds/Wetlands LI Dry Extended Detention Basins LI Infiltration Basins LI Bio-Retention Areas 0 Sand or Organic Filters I 0 Z Hydrodynamic Separators 0 Infiltration Trenches Catch Basin/Inlet Inserts 0 Other (Explained Below) ' Of the treatment control options available for this project, infiltration practices are not feasible due to the preponderance of hydrologic soil type D throughout the site, which has poor infiltration properties. Wet ponds and constructed wetlands rely on a perennial water source, which is generally difficult to sustain in the project's arid environment. While filtration devices, such as sand filters and media filters, typically have medium to high removal efficiencies for the project's pollutants of concern, they are aesthetically unsuitable for use in developments such as this project. An underground sand/media I filter might improve aesthetics, but these are not recommended for drainage areas greater than 2 acres (2003 California New Development BMP Handbook, Fact Sheet TC-40), and the proposed project covers 4.58 acres. Since the proposed project site consists of a generally flat graded pad, implementing several filters for smaller drainage I areas is not feasible due to the lack of required head needed to ensure that water passes through the filter. 4.4.1.1 Drainage Filter Inserts I La Costa Resort Planning Area 1, Building 9A-9B, bA-10E 15 Storm Water Management Plan WF LUrIy • _• ',uI_' Li ii ji - E all ii-.:.. F:il P Prr:h Liner Cnt Pipe 4ISqp<iEinr SIDE STORM WATER MANAGEMENT PLAN To provide additional treatment and removal of potential pollutants, drainage inlet inserts will be installed in all storm drain inlets capturing runoff from the parking lots. Kristar Floguard Plus® inserts or equivalent will be specified to treat runoff for hydrocarbons and trash/debris. The Kristar Floguard Plus® inlet insert is shown in Figure 4-1, and is similar in design and function to other proprietary inlet inserts. Surface runoff enters the inlet and passes over/through an adsorbent material to remove hydrocarbons, while sediments and trash/debris are collected in the hanging basket. Recommended maintenance consists of three inspections per year (once before the wet season and two during, or more as may be needed) plus replacement of the adsorbent when it is more than 50% coated with pollutants and removal of excessive sediment/debris. Each inlet insert costs about $570 and is available locally through Downstream Services (760-746- 2544 or 760-746-2667). The inserts can be installed by Downstream Services for additional cost or by the project construction contractor. Maintenance costs are estimated at about $400 per year. (Refer to Appendix B for design calculations). Figure 4-1 Kristar Floguard Plus® Inlet Insert 4.4.1.2 Hydrodynamic Separators An in-line storm water treatment unit (CDS unit) exists at the downstream end of the campus-wide storm drain system, as proposed within the approved Master Storm Water Management Plan, prepared by Rick Engineering, dated October 29, 2003. The storm water treatment units are mechanical separators that physically reduce sediment, trash, debris, and oil and grease from the flow and pesticides that attached to sediment. The unit is considered a hydrodynamic separator system. The hydrodynamic separator systems rank low to medium in removal efficiency for the project's pollutants of concern. La Costa Resort Planning Area 1, Building 9A-9B, bA-10E 16 Storm Water Management Plan IBF STORM WATER MANAGEMENT PLAN Refer to the approved Master Drainage Study for La Costa Resort & Spa, prepared by Hunsaker Associates, dated September 15, 2006, for back-up calculations regarding the storm water treatment unit. 4.4.1.3 Vegetated Swales Vegetated swales are affective at treating runoff through filtering by the vegetation in the channel and filtering through a subsoil matrix. Vegetated swales are proposed within the median islands of the parking lot area. The majority of the onsite runoff flows west into the parking lot, where it will enter one of the two swales onsite. Flow travels slowly through the swale before entering a grate inlet. (Refer to Appendix B for design calculations) 4.5 Construction-Phase BMPs Additional best management practices to prevent reduce, and/or treat storm water pollution will be implemented during the construction phase of the project. Because the site is greater than 1 acre (as required by the NPDES General Permit) and because it is considered a Medium Priority Construction Project by the City of Carlsbad, a Storm Water Pollution Prevention Plan (SWPPP) will be developed for the project site under separate cover and will be incorporated by reference into this document. 5 LOW IMPACT DEVELOPMENT Low Impact Development (LID) is an alternative method of land development that seeks to maintain the natural hydrologic character of the site. Per the Draft County of San Diego Low Impact Development Handbook and in anticipation for the future City of Carlsbad Municipal Permit LID requirement, LID BMPs have been included as part of our site design. LID BMPs will collectively minimize directly connected impervious areas and promote infiltration 5.1 1 Pervious Pavement Pervious pavement will be used in a portion of the parking lot. The advantages of pervious pavement are that they reduce runoff volume while providing treatment and are unobtrusive. It is comprised of a permeable surface placed over a granular course on top of a reservoir of large stone. The pervious pavement has been designed according to the recommendations of the 2003 California New Development BMP Handbook, Fact Sheet SD-20. Pervious pavement has high removal efficiencies for all potential pollutants identified for this site. 5.2 Roof Runoff Disconnect A portion of the roof drainage will drain into pervious areas prior to entering the closed drainage system. This disconnect allows an opportunity to reduce rate and increase infiltration at the project site. La Costa Resort Planning Area 1 Building 9A 9B 1OA 1OE 17 Storm Water Management Plan PF I I I I I I I I I I U I I I I I U I H I I I I 1 I I I I I 1 I I I I I I I I STORM WATER MANAGEMENT PLAN 5.3 ParkingLot Filter StripsNegetated Swales Based on anticipated pollutants and the primary pollutants of concern, two four-foot wide filter strips are being incorporated into the parking lot design. The filter strips will utilize the allowable overhang area for a total width of four feet. The filter strips will be designed to treat run-off and ultimately connect storm water with the closed drainage system. 6 MAINTENANCE To ensure long-term maintenance of project BMPs, the project proponent will enter into a contract with the City of Carlsbad to obligate the project proponent to maintain, repair and replace the storm water BMP as necessary into perpetuity. Security will be required in the form of a Letter of Credit. The site shall be kept in a neat and orderly fashion With a regularly scheduled landscape maintenance crew in charge of keeping gutters and inlets free of litter and debris. The landscape crew will also maintain the landscaping to prevent soil erosion and minimize sediment transport. The project consists of a series of catch basins, which will include Kristar Floguard Plus® inlet inserts. It is recommended that the hydrocarbon absorption booms be replaced four times per year. Currently the approximate cost to replace each boom is $100.00. This amounts to a maintenance cost of $400.00 per year, per inlet. Maintenance records shall be retained for at least 5-years. These records shall be made available to the City of Carlsbad for inspection upon request. La Costa Resort Planning Area 1, Building 9A-9B, bA-10E 18 Storm Water Management Plan PF I I 1 I I I I I I I I I I I I I I I I I I I i I I I I i i I I I I I U I Project Address Assessors Parcel Number(s): Project # (city use only): Estrella De Mar Road 216-591-02,03,04,08,15,21,23 CT 07-08 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 pny 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 Proiect Permanent Storm Water BMP Reaulrements. Does the project meet the definition of one or more of the priority project categories?* Yes No 1. Detached residential development of 10 or more units. 2.. Attached residential development of 10 or more units 1 Commercial development greater than 100,000 square feet. 4.. Automotive repair shop. Restaurant, 11111 Steep hillside development greater than 5,000 square feet. El Z Project discharging to receiving waters within Environmentally Sensitive Areas., LII Parking lots greater than or equal to 5,000 ft or with at least 15 parking spaces, and W] El 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 * 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. I Li r.& . 4.I...,.i 0 - ---# Q+#%Pm W*r Does the project propose: Yes No 1. New impervious areas, such as rooftops, roads, parking lots, driveways, paths and sidewalks? New landscape and irrigation systems? pervious areas Permanent structures within 100 feet of any natural water body? Owl Trash storage areas? 1:11IJ Liquid or solid material loading and unloading areas? E]I ZI Vehicle or equipment fueling, washing, or maintenance areas? ]IFI T. Require a General NPDES Permit for Storm Water Discharges Associated with Industrial - L-1 - Activities (Except construction)?* - 8.. Commercial or industrial waste handling or storage, excluding typical office or household 11 waste? Any grading or ground disturbance during construction? F 1 Any new storm drains, or alteration to existing storm drains? W] 1:1 *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..qov/stormwtr/industrial.html Section 2. Construction Storm Water BMP Requirements: If the answer to question I 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.. f'.....4... WfQr Qat,Iirrna,lfQ Would the project meet any of these criteria during construction? Yes No 1,, Is the project subject to California's statewide General NPDES Permit for Storm Water Discharges Associated With Construction Activities? z 1:1 Does the project propose grading or soil disturbance? Fv/1 Eli 1 Would storm water or urban runoff have the potential to contact any portion of the construction area, including washing and staging areas? - Would the project use any construction materials that could negatively affect water quality if discharged from the site (such as, paints, solvents, concrete, and stucco)? 121 El I I I I I I 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 necessary to complete the construction and any other extenuating 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] J A) High Priority 1) Projects where the site is 50 acres or more and grading will occur during the rainy season 2) Projects I acre or more.. 3) Projects I acre or more within or directly adjacent to or discharging directly to a coastal lagoon or other receiving water within an environmentally sensitive area 4) Projects, active or inactive, adjacent or tributary to sensitive water bodies B) Medium Priority 5) 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.) 6) 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.. 7) Permit projects on private property where grading permits are required, however, Notice Of Intents (NOls) and SWPPPs are not required. C) Low Priority 8) Capital Projects where minimal to no grading occurs, such as signal light and loop installations, street light installations, etc.. 9) Permit projects in the public right-of-way where minimal to no grading occurs, such as pedestrian ramps, driveway additions, small retaining walls, etc.. 10) Permit projects on private property where grading permits are not required, such as small retaining walls, single-family homes, small tenant improvements, etc. Owner/Agent/Engineer Name (Please Print): Title: Tim Thiele, RBF Consulting Project Engineer Signature Date: I I I I I I 1 I I I I I I 1 I 1 I i I I I I I I I I I I I I I I I 1 I I I I Site Design & Landscape Planning SD-10 Design Objectives Maximize Infiltration Provide Retention Ea Slow Runoff Minimize Impervious Land Coverage Prohibit Dumping of Improper Materials Contain Pollutants Collect and Convey Description Each project site pcsssses unique topographic, hydrologic, and vegetative features, some of which are more suitable for develoçment than others. Integrating and incorporating appropriate landscape plaaning niehodoIogies into the project design is the most effective action that can be d ne :o minimize surface and groundwater contamination from stormwater. Approach Lands cape planning should couple consideration of land suitability for urban uses with consideration of community goals ind projected growth. Project plan designs should conserve natural areas to the exteit possible, maximize natural water storage and infiltration opportunitaes, and protect slopes and channels. Suitable Applications Appropriate apphcatior.; include re idential, commercial and industrial areas planned for development or redevelopintit. Design Considerations Design requirements to: site design arid landscapes planning should cononui to applicable standards and speifications of agencies with jurisdiction and be coosistent with applicable General Plan and Local Area Plan policies. January 2003 Call ::.rnla Stormwater BMP Handbook 1 of 4 New Development and Redevelopment www.cebmpliandbooks.com SD-10 Site Design & Landscape Planning Designing New Installations Begin the development of a plan for the landscape unit with attention to the following general principles: Formulate the plan on the basis of clearly articulated community goals. Carefully identify conflicts and choices between retaining and protecting desired resources and community growth Map and assess land suitability for urban uses. Include the following landscape features in the assessment: wooded land, open unwooded land, steep slopes, erosion-prone soils, foundation suitability, soil suitability for waste disposal, aquifers, aquifer recharge areas, wetlands, floodplains, surface waters, agricultural lands, and various categories of urban land use. When appropriate, the assessment can highlight outstanding local or regional resources that the community determines should be protected (e.g., a scenic area, recreational area, threatened species habitat, farmland, fish run). Mapping and assessment should recognize not only these resources but also additional areas needed for their sustenance. Project plan designs should conserve natural areas to the extent possible, maximize natural water storage and infiltration opportunities, and protect slopes and channels. Conserve Natural Areas during Landscape Planning If applicable, the following items are required and must be implemented in the site layout during the subdivision design and approval process, consistent with applicable General Plan and Local Area Plan policies: Cluster development on least-sensitive portions of a site while leaving the remaining land in a natural undisturbed condition. Limit clearing and grading of native vegetation at a site to the minimum amount needed to build lots, allow access, and provide fire protection. Maximize trees and other vegetation at each site by planting additional vegetation, clustering tree areas, and promoting the use of native and/or drought tolerant plants. Promote natural vegetation by using parking lot islands and other landscaped areas. Preserve riparian areas and wetlands. Maximize Natural Water Storage arid Infiltration Opportunities Within the Landscape Unit Promote the conservation of forest cover. Building on land that is already deforested affects basin hydrology to a lesser extent than converting forested land. Loss of forest cover reduces interception storage, detention in the organic forest floor layer, and water losses by evapotranspiration, resulting in large peak runoff increases and either their negative effects or the expense of countering them with structural solutions. Maintain natural storage reservoirs and drainage corridors, including depressions, areas of permeable soils, swales, and intermittent streams. Develop and implement policies and 2 of 4 California Stormwater BMP Handbook January 2003 New Development and Redevelopment - www.cabmphandbooks.com Site Design & Landscape Planning SD-10 regulations to discourage the clearing, filling, and channelization of these features Utilize them in drainage networks in preference to pipes, culverts, and engineered ditches. Evaluating infiltration opportunities by referring to the stormwater management manual for the jurisdiction and pay particular attention to the selection criteria for avoiding groundwater contamination, poor soils, and hydrogeological conditions that cause these facilities to fail If necessary, locate developments with large amounts of impervious surfaces or a potential to produce relatively contaminated runoff away from groundwater recharge areas. Protection of Slopes. and Channels during Landscape Design a Convey runoff safely from the tops of slopes.. Avoid disturbing steep or unstable slopes. a Avoid disturbing natural channels. Stabilize disturbed slopes as quickly as possible. a Vegetate slopes with native or drought tolerant vegetation - control and treat flows in landscaping and/or other controls prior to reaching existing natural drainage systems. I • Stabilize temporary and permanent channel crossings as quickly as possible, and ensure that increases in run-off velocity and frequency caused by the project do not erode the channel I a install energy dissipaters, such as riprap, at the outlets of new storm drains, culverts, conduits, or channels that enter unlined channels in accordance with applicable specifications to minmuze erosion Energy dissipaters shall be installed in such away as to minimize impacts to receiving waters. a Line on-site conveyance channels where appropriate, to reduce erosion caused by increased flow velocity due to increases in tributary impervious area The first choice for hmngs should be grass or some other vegetative surface, since these materials not only reduce runoff velocities, but also provide water quality benefits from filtration and infiltration If velocities in the channel are high enough to erode grass or other vegetative linings, nprap, concrete, soil cement, or geo-grid stabilization are Other alternatives. a Consider other design principles that are comparable and equally effective. Redeveloping Existing Installations Various jurisdictional stormwater management and mitigation plans (SUSMP, WQMP, etc.) define "redevelopment" in terms of amounts of additional impervious area, increases in gross floor area and/or exterior construction, and land disturbing activities with structural or impervious surfaces The definition of" redevelopment" must be consulted to determine whether or not the requirements for new development apply to areas intended for redevelopment. If the definition applies, the steps outlined under "designing new installations" above should be followed. January 2003 California Stormwater BMP Handbook 3 of 4 New Development and Redevelopment www.cabmphandbooks.com SD-10 Site Design & Landscape Planning Redevelopment may present significant opportunity to add features which had not previously been implemented. Examples include incorporation of depressions, areas of permeable soils, and swales in newly redeveloped areas While some site constraints may exist due to the status of already existing infrastructure, opportunities should not be missed to maximize infiltration, slow runoff, reduce impervious areas, disconnect directly connected impervious areas. Other Resources A Manual for the Standard Urban Stormwater Mitigation Plan (SUSMP), Los Angeles County Department of Public Works, May 2002. Stormwater Management Manual for Western Washington, Washington State Department of Ecology, August 2001. Model Standard Urban Storm Water Mitigation Plan (SUSMP) for San Diego County, Port of San Diego, and Cities in San Diego Courty, February 14, 2002. Model Water. Quality Management Plan (WQMP) for County of Orange, Orange County Flood Control District, and the Incorporated Cities of Orange County, Draft February 2003 Ventura Countywide Technical Guidance Manual for Stormwater Quality Control Measures, July 2002. 4 of 4 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Efficient Irrigation SD-12 Design Objectives 0 Maximize Infiltration Provide Retention El Slow Runoff Minimize Impervious Land Coverage Prohibit Dumping of Improper Materials Contain Pollutants Collect and Convey Description Irrigation water prDvided to landscaped areas may result in excess irrigation water being conveyed into stormwater drainage systems. Approach Project plan designs for developnnt and redevelopment should include application methods of irrigation water that minimize runoff of excess irrigation water into the stormwater conveyance system. Suitable Applications Appropriate applications include residential, commercial and industrial areas planned for development or redevelopment. iDetaithed residential single-family honies are typically excluded from this requirenielit.) Design Considerations Designing New Installations The following metLods to reduce excessive irrigation rimoff should be considered, and incorporated and implemented where determined applicable and feasible by the Permittee: Employ rain-triggered shutoff deviecs to prevent irrigation after precipitation. Design irrigaticn systems to each landscape area's specific water requirements. Include design featuring flow reducers or shutoff valves triggered by a pressure drop tc control water loss in the event of broken sprinkler heads or 11iies. Implement landscape plans cisistr nt with County or City water conservation resolutioin, which may include provision of water sensors, programinab4e irrigation times (for short cycles), etc. A January 2003 California Storniwater BMP Handbook 1 of 2 NEN,v Development and Redevelopment www.cabmphandbooks.com SD-12 Efficient Irrigation Design timing and application methods of irrigation water to minimize the runoff of excess irrigation water into the storm water drainage system. Group plants with similar water requirements in order to reduce excess irrigation runoff and promote surface filtration. Choose plants with low irrigation requirements (for example, native or drought tolerant species). Consider design features such as: - Using mulches (such as wood chips or bar) in planter areas without ground cover to minimize sediment in runoff Installing appropriate plant materials for the location, in accordance with amount of sunlight and climate, and use native plant materials where possible and/or as recommended by the landscape architect - Leaving a vegetative barrier along the property boundary and interior watercourses, to act as a pollutant filter, where appropriate and feasible - Choosing plants that minimize or eliminate the use of fertilizer or pesticides to sustain growth Employ other comparable, equally effective methods to reduce irrigation water runoff. Redeveloping Existing Installations Various jurisdictional stormwater management and mitigation plans (SUSMP, WQMP, etc.) define "redevelopment" in terms of amounts of additional impervious area, increases in gross floor area and/or exterior construction, and land disturbing activities with structural or impervious surfaces. The definition of" redevelopment" must be consulted to determine whether or not the requirements for new development apply to areas intended for redevelopment. If the definition applies, the steps outlined under "designing new installations" above should be followed. Other Resources A Manual for the Standard Urban Stormwater Mitigation Plan (SUSMP), Los Angeles County Department of Public Works, May 2002. Model Standard Urban Storm Water Mitigation Plan (SUSMP) for San Diego County, Port of San Diego, and Cities in San Diego County, February 14, 2002. Model Water Quality Management Plan WQMP) for County of Orange, Orange County Flood Control District, and the Incorporated Cities of Orange County, Draft February 2003. Ventura Countywide Technical Guidance Manual for Stormwater Quality Control Measures, July 2002. 2 of 2 California Stormwater BMP Handbook - January 2003 New Development and Redevelopment www.cabmphandbooks.com Storm Drain Signaçje SD-13 Design Objectives Maximize Infiltration Provide Retention Slow Runoff Minimize Impervious Land Coverage Prohibit Dumping of Improper Materials Contain Pollutants Collect and Convey Description Was-:e materials dumped into storm drain nhts can iave severe impacts on receiving and ground waters. Posting notices regarding disr±arge prohibitions at storm drain inlets can prevent waste dumping. Storm drain signs ar stencils are highly visible source controls that r.re typically placed directly adjacent t stom drain inlets. Approach The stencil or affixed sign contains a brief siateinent that prohibits dumping of improper rnrtrials into the urban runoff conveyance system. Storm drain messages have become a p03ula r method of alerting the public about the effec:s of and the prohibitions against waste disposal Suitable Applications Stencils and signs alert the puJlic to the de Ii nat oii of pollutants discharged to the storm dran. Signs are appropriate in residential, conL-nercial, and industrial areas as well as any other area where contributions or dumping to storm dra is is likely. Design Considerations Storm drain message markers or placard .re roiiini mded at all storm drain inlets within the Foundary of a development project. The inarer should be placed in clear sight facing toward ar.vcne approaching the inlet from eiLier side. All storm drain inlet locations should be id ant ified on the development site mafl. Designing New Installations The following methods should be considered cor inclusion in the cri!ject design and show on project plans Provide stenciling or labeling of all storm drain inlets and ctch basins, constructed or modified, within the project area vith prohibitive language. Examples in cluc e "NO DUMPING A Janiay 2D03 California 3tci-rrwater EMP Handbook 1 of 2 New Development and RdaveIoprnent www. ca rr lia ric hooks.corn SD-13 Storm Drain Signage - DRAINS TO OCEAN" and/or other graphical icons to discourage illegal dumping. Post signs with prohibitive language and/or graphical icons, -%,vliicli prohibit illegal dumping at public access points along channels and creeks within the project area. Note - Some local agencies have approved specific signage and/or storm drain message placards for use. Consult local agency stormwater staff to determine specific requirements for placard types and methods of application. Redeveloping Existing Installations Various jurisdictional stornrwater management and mitigation plans (SUSMP, WQMP, etc.) define "redevelopment" in terms of amounts of additional impervious area, increases in gross floor area and/or exterior construction, and land disturbing activities with structural or impervious surfaces. If the project meets the definition of "redevelopment", then the requirements stated under" designing new installations" above should be included in all project design plans. Additional Information Maintenance Considerations Legibility of markers and signs should be maintained. If required by the agency with jurisdiction over the project, the owner/operator or homeowner's association should enter into a maintenance agreement with the agency or record a deed restriction upon the property title to maintain the legibility of placards or signs. Placement Signage on top of curbs tends to weather and fade. Signage on face of curbs tends to be worn by contact with vehicle tires and sweeper brooms. Supplemental Information Examples Most MS4 programs have storm drain signage programs. Some MS4 programs will provide stencils, or arrange for volunteers to stencil storm drains as part of their outreach program. Other Resources A Manual for the Standard Urban Stormwater Mitigation Plan (SUSMP), Los Angeles County Department of Public Works, May 2002. Model Standard Urban Storm Water Mitigation Plan (SUSMP) for San Diego County, Port of San Diego, and Cities in San Diego County, February 14, 2002. Model Water Quality Management Plan (WQMP) for County of Orange, Orange County Flood Control District, and the Incorporated Cities of Orange County, Draft February 2003. Ventura Countywide Technical Guidance Manual for Stormwater Quality Control Measures, July 2002. I 2 of 2 CaliforniaStormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Design Objectives EZI Maximize Infiltration F1 Provide Retention IZI Slow Runoff Minimize Impervious Land Coverage Prohibit Dumping of Improper Materials Contain Pollutants Collect and Convey Pervious Pavements SD-20 II'TT I ' - - -r i_ ;1 ................................ -- Description Pervious paving is used for light vehicle loading in parking areas. The term describes a system comprising a load-bear-ng, durable surface together with an underlying layered structure that temporarily stores watr r prior to infiltration or drainage to a controlled outlet. The surface can itself be porous such th.-it water infiltrates acrs the entire s irface of the material (e.g., grass and gravel surfaces, porous concrete and porous asphalt), or can be built up of impermeable blocks septrated by spes and joints, through which the wa:ei can drain. This latter system is termed 'pe rineahie' paving. Advantages of pervous pavements is that they reduce runoff volume while providing treatment, and are unobtrusive resuiting in a high level of acceptability. Approach Attenuation of flow is p ovided by the storage within the underlying structure or sub base, together with approprirte flow controls. An underlying geotextile may permit groundwater recha:ge, thus contribuTing to the restoration of the natural water cycle. Alternatively, where infiltration is inappropriate (e.g., if the groundwater vuhierai1ity is high, or the soil type is unsui:able), the surface can be constructed above an imperu: eable membrane. The system offers a valuable solution for drainage of spatially constrained urbwi areas. Significant attenuation and improvement in water quality ca oe achieved by permeable pavements, whichever method is used. The su:lace and subsurface infrastructure can remove both the soluble and fine particulate pollutants that occur wi:hin urban runoff. Roof water can be piped into the storage area directly, adding areas from whic the flow can be attenuated. Also, within lined systems, there is the opportunity for stored runoff to be piped out for reuse. Suitable Applications Residential, com:rjercia. and industrial applications are poss:ble. The use of permeable pavement may be restriccd in cold re:s, and regions or regions with high wind erosion. There are some specific disadvantages associated with permeable pavement, which are as follows: ft:A January 20T Caltfcrnia Stormvater BMP Handbook 1 of 10 New Development and Redeveloprie it www.cabmpiandbooks.com SD-20 Pervious Pavements Permeable pavement can become clogged if improperly installed or maintained. However, this is countered by the ease with which small areas of paving can be cleaned or replaced when blocked or damaged. Their application should be limited to highways with low traffic volumes, axle loads and speeds (less than 30 mph limit), car parking areas and other lightly trafficked or non- trafficked areas. Permeable surfaces are currently not considered suitable for adoptable roads due to the risks associated with failure on high speed roads, the safety implications of ponding, and disruption arising from reconstruction. When using un-lined, infiltration systems, there is some risk of contaminating groundwater, depending on soil conditions and aquifer susceptibility. However, this risk is likely to be small because the areas drained tend to have inherently low pollutant loadings. The use of permeable pavement is restricted to gentle slopes. a Porous block paving has a higher risk of abrasion and damage than solid blocks. Design Considerations Designing New Installations If the grades, subsoils, drainage characteristics, and groundwater conditions are suitable, permeable paving may be substituted for conventional pavement on parking areas, cul de sacs and other areas with light traffic. Slopes should be flat or very gentle. Scottish experience has shown that permeable paving systems can be installed in a wide range of ground conditions, and the flow attenuation performance is excellent even when the systems are lined. The suitability of a pervious system at a particular pavement site will, however, depend on the loading criteria required of the pavement. Where the system is to be used for infiltrating drainage waters into the ground, the vulnerability of local groundwater sources to pollution from the site should be low, and the seasonal high water table should be at least 4 feet below the surface. Ideally, the pervious surface should be horizontal in order to intercept local rainfall at source. On sloping sites, pervious surfaces may be terraced to accommodate differences in levels. Design Guidelines Time design of each layer of the pavement must be determined by time likely traffic loadings and their required operational life. To provide satisfactory performance, the following criteria should be considered: The subgrade should be able to sustain traffic loading without excessive deformation. The granular capping and sub-base layers should give sufficient load-bearing to provide an adequate construction platform and base for the overlying pavement layers. The pavement materials should not crack of suffer excessive rutting under the influence of traffic. This is controlled by the horizontal tensile stress at the base of these layers. 2 of 10 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com I Pervious Pavements SD-20 There is no current structural design method specifically for pervious pavements. Allowances should be considered the following factors in the design and. specification of materials: I Pervious pavements use materials with high permeability and void space. All the current UK pavement design methods are based on the use of conventional materials that are dense and I relatively impermeable. The stiffness of the materials must therefore be assessed. Water is present Within the construction and can soften and weaken materials, and this must I be allowed for. Existing design methods assume full friction between layers. Any geotextiles or I ,. geomembranes must be carefully specified to minimize loss of:friction between layers. Porous asphalt loses adhesion and becomes brittle as air passes through the voids Its I durability is therefore lower than conventional materials. The single sized grading of materials used means that care should be taken to ensure that loss of finer particles between unbound layers does not occur. I Positioning a geotextile near the surface of the pervious construction should enable pollutants to be trapped and retained close to the surface of the construction This has both advantages and disadvantages The main disadvantage is that the filtering of sediments and their associated I pollutants at this level may hamper percolation of waters and can eventually lead to surface ponding. One advantage is that even if eventual maintenance is required to reinstate infiltration, only a limited amount of the construction needs to be disturbed, since the sub-base I below the geotextile is protected In addition; the pollutant concentration at a high level in the structure allows for its release over time It is slowly transported in the stormwater to lower I levels where chemical and biological processes maybe operating to retain or degrade pollutants. The design should ensure that sufficient void space exists for the storage of sediments to limit the period between remedial works I Pervious pavements require a single size grading to give open voids The choice of materials is therefore a compromise between stiffness, permeability and storage capacity. I • Because the be in for large 'part sub-base and capping will contact with water a of the time, the strength and durability of the, aggregate particles when saturated and subjected to I wetting and drying should be assessed. . A uniformly graded single size material cannot be compacted and is liable to move when I rock construction traffic passes over it. This effect can be reduced by the use of angular crushed material with a high surface friction. In pollution control terms, these layers represent the site of long term chemical and biological I pollutant retention and degradation processes The construction materials should be selected, in addition to their structural strength properties, for their ability to sustain such processes In general, this means that materials should create neutral or slightly alkaline conditions and they I should provide favorable sites for colonization by microbial populations. I January 2003 ' California Stormwater BMP Handbook 3 of 10 I New Development and Redevelopment www.cabrnphandbooks.com SD-20 Pervious Pavements Construction/Inspection Considerations u Permeable surfaces can be laid without cross-falls or longitudinal gradients. . The blocks should be lain level They should not be used for storage of Site materials, unless the surface is well protected from deposition of silt and other. spillages The pavement should be constructed in a single operation.. as one of the last items to be built, on a development site Landscape development should be completed before pavement construction to avoid contamination by silt or soil from this source Surfaces draining to the pavement shouldbe stabilized before construction of the pavement. Inappropriate construction equipment should be kept away from the pavement to prevent damage to the surface, sub-base or subgrade. Maintenance Requirements The maintenance requirements of a pervious surface should be reviewed at the time of design and should be clearly specified Maintenance is required to prevent clogging of the pervious surface The factors to be cOnsidered when. defining maintenance requirements must include: Type of use Ownership Level of trafficking The local envirOnment and any contributing catchments Studies in the UK have shown satisfactory operation of porous pavement systems without maintenance for over 10 years and recent work by Imbe et al at 9th ICUD, Portland, 2002 describes systems operating for over 20 years without maintenance However, performance under such regimes could not be guaranteed, Table 1 shows typical recommended maintenance regimes: 4 of 10 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Pervious Pavements SD-20 Table 1 Typical Recommended Maintenance Regimes Activity Schedule i Minimize use of salt or grit for de-icing i Keep landscaped areas well maintained Ongoing i Prevent soil being washed onto pavement Vacuum clean surface using commercially available sweeping machines at the following times: - hind of winter (April) 2/3 xper year: Mid-summer (July / August) - After Autumn leaf-fall (November) Inspect outlets Annual Ifroutine.cleaning does not restore infiltration rates, then reconstruction of part of the whole of a pervious surface may be required. The surface area affected by hydiauhc failure should be lifted for mspection of the mternal matenals to identify the location and As needed (infrequent) extent of the blockage. MaiCÜmUII 15-20 years Surface materials should be lifted and replaced after brush cleaning. Geotextiles may need complete replacement. Sub-surface iayers.rnay need cleaning and replacing. Removed silts may need to be disposed of as controlled waste Permeable pavementsare up to 25 %cheaper (or at least no more expensive than the traditional I forms of pavement construction), when all construction and drainage costs are taken into account (Accepting that the porous asphalt itself is a more expensive surfacing, the extra cost of which is offset by the savings in underground pipework etc) (Niemczynowicz, et al, 1987) 1 Table 1 gives US cost estimates for capital and. maintenance costs of porous pavements (Landphair et al , 2000) I Redeveloping Existing Installations Various junsdictional stormwater management and mitigation plans (SUSMP, WQMP, etc) define "redevelopment" in terms of amounts of additional impervious area, increases in gross I floor area and/or exterior construction, and land disturbing activities with structural or impervious surfaces The definition of redevelopment" must be consulted to determine whether or not the requirements for new development apply to areas intended for I redevelopment If the definition applies, the steps outlined under "designing new installations" above should be followed. i i January 2003 California Storrnwater BMP Handbook 5 of 10 I New Development and Redevelopment wwwcabmphandbooks.com I I I I I I I I I I SD-20 Pervious Pavements Additional Information Cost Considerations Permeable pavements are up to 25 1/6 cheaper (or at least no more expensive than the traditional forms of pavement construction), when all construction and drainage costs are taken into account (Accepting that the porous asphalt itself is a more expensive surfacing, the extra cost of which is offset by the savings .in underground pipework etc) (Niernczynowicz, et al, 1987) Table 2 gives US cost estimates for capital and maintenance costs of porous pavements (Landphair et at, 2000) 5 of 10 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks,com - - - - - M. - - - - - M. - - - - . u.m Pervious. Pavements SD20 Table 2 Engineer's Estimate for Porous Pavement Porous Pavement_____ Item Var 11wis.CE T~IajlCycleI QaaM1 AcieVS TOW Quiai.2 AereWS Qaait.3 Acre WS Total Quant.4 AcreWS I 0 T Acre %VS TOW Gradmg SY $200 604 $1,208 1209 $2418 1812 $3824 2419 $4836 3020 $6040 Paving SY $1900 212 $4,028 424 $8058 836 $12084 848 $16112 1060 820140 Ixcavaton CV $360 201 $724 403 $1451 604 $2174 806 $2902 10*9 $3629 FlttevFabic SY $11-16 700 $805 1400 $1,610 2000 $2300 2800 $3,220 3600 $4,140 Storn Fill CV $1800 201 $3,216 403 $6,448 604 $9,064 608 $12,896 1008 $16,128 Sand CV $700 100 $700 200 31400 300 520100 40* $2800 500 $3500 Slight WONEA .6300.00 2 $600 3 $900 4 $1200 7 $2,100 7 $2,100 Sdg LF $005: ... 644 . $32 1288. $64 1932.... 597 1 2578 $129 3220 5161 Checkl)arn CV $36.00 0 :$0 0 $0 0 $0 0 $0 0 $0 Tothi Conshuctloi Costs $10,105 $19929 $29619 $40,158 $49,798 ?oit1ion Costs Amortited for 20 Years $1,491 $2,008 $2,490 Annual Maintenance Expense Item Units price (vduI Year Q,ant.l Acre WS Total Quanl.2 AereWS t iii 0 AcreWS Total AcreWS Total AcreWS Total Sweeping AC $25000 6 1 $1,500 2 $3.000 3 $4,500 4 $6000 5 $7500 Washing AC $25000 6 1 $1,500 2 $3,000 3 $4 800 4 $6000 5 $7,6w InspectIon MH $2000 5 5 $100 5 $100 5 $100 L 5 $100 5 $100 DsepCtean AC 1 $46000 05 1 $225 2 $450 1 3 $875 39 $818 5 $1 125 TbI Miwal MallMOMMO EXp.. $3,980,.. $7,792 $11,051 $15,483 January 2003 California Stomiwater BMPilandboók 7 o 10 New Development and Redevelopment www.cabrnpha ndbOoks corn SD-20 Pervious Pavements I Other Resources Abbott C.L. and Comino-Mateos L. 2001 In situ performance monitoring of an infiltration drainage system and field testing of current design procedures Journal cIWEM, 15(3), PP-198- 202. Construction Industry Research and Information Association (CIRIA). 2002. Source Control using Constructed Pervious Surfaces C582, London, SWiP 3AU. Construction Industry Research and Information Association (CIRIA). 2000. Sustainable urban drainage systems - design manual for Scotland and Northern Ireland Report i521, London, SWiP 3AU. Construction Industry Research and Information Association (CIRIA). 2000 C522 Sustainable urban drainage systems - design manual for England and Wales, London, SWiP 3AU Construction Industry Research and Information Association (CIRIA). RP448 Manual of good practice for the design, construction and maintenance of infiltration drainage systems for stormwater runoff control and disposal, London, SWiP 3AU Dierkes C., Kthlmann L, Kandasamy J. &Angelis G. Pollution Retention Capability and Maintenance of Permeable Pavements. Proc International Conference on'Urban Drainage, Portland Oregon, September 2002 Hart P (2002) Permeable Paving as a Stormwater Source Control System. Paper presented at Scottish Hydraulics Study Group 14th Annual seminar, SUDS 22 March 2002, Glasgow Kobayashi M., i999 Stormwater runoff control in Nagoya City. Proc. 8 th:Iflt .Conf. on Urban Storm Drainage, Sydney, Australia, pp.825-833. Landpliair, H., McFalls, J., Thompson, D., 2000, Design Methods, Selection, andCpst Effectiveness of Stormwater Quality Structures, Texas Transportation Institute Research Report 1837-1, College Station, Texas. Legret.M, Colandini V, Effects of a.porous pavement with reservior strucutre on runoff Water water quality and the fate of heavy metals Laboratoire Cential Des Ponts et Chaussesss Macdonald K & Jefferi s C. Performance Comparison of Porous Paved and Traditional Car Parks. Proc. First National conference on Sustainable Drainage Systems, Coventry June 2001. Niemczynowicz J, Hogland W, 1987-.:Test of porous pavements performed in Lund, Sweden, in Topics in Drainage Hydraulics and Hydrology. BC Yen (Ed ), pub mt Assoc For Hydraulic Research, pp-19-80. Pratt C.J. SUSTAINABLE URBAN DRAINAGE - A Review of published material on the performance of various SUDS devices prepared for the UK Environment Agency. Coventry University, UK December 2001. Pratt C.J., 1995. Infiltration drainage - case studies of UK practice. Project Report 8 of 10 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Pervious Pavements SD-20 22,Construction Industry Research and Information Association, London, .SWIP 3AIJ; also known as National Rivers Authority R &D Note 485 Pratt. C. J., 1990. Permeable Pavements for Stormwater Quality Enhancement. In: Urban Stormwater Quality Enhancement - Source Control, retrofitting and combined sewer technology, Ed H C Torno, ASCE, ISBN 087262 7594, pp 131-155 Raimbault G., 1997 French Developments in Reservoir Structures Sustainable, water resources I the 21 century. Malmo Sweden Sclhhiter W. & Jefferies C Monitoring the outflowfrom a Porous Car Park Proc. First National Go7ference. on Sustainable Drainage Systems, Coventry June 2001. Wild, Jefferles, C., and .D'Arcy, BJ SUDS in Scotland the Scottish SUDS database Report No SR(02)09 Scotland and Northern Ireland Forum for Environmental Research, Edinburgh. Iii preparation August2002. January 2003 California Stormwater BMP Handbook 9 of 10 New Development and Redevelopment www.cabmphandbooks.com SD-20 Pervious Pavements Geottøe A pm UbSB 1 mpanneabe - urThr ueament dspo v t•f• • - - Pemcable GeotextB ' Membrane r a) Pervious pavement used tr atIeaLstion b) Psrvlaus pavement Uftd 10 Infiltration Schematics of a Pervious Pavement System 10 of 10 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com RBF C 0 N S U LTJ N 9 PLANNING U DESIGN • CONSTRUCTION 800.479,3808 • WWWR8FOM JOB SHEET NO _________________ OF CALCULATED BY UCO DATE I zJc CHECKED BY DATE SCALE P vtt$ — kr 4-? P-ivla 'ip coc ,h+ SA/ DIEGO COO,VT t1' bqS/v, s4omje vcU41( L (c AScA I 1 14 pped ô) Pec'ViOS ey.-ir?+ Ar A-re 4- ' i4-Ppeii' C- iqe (a 59 3 0F.3 3 (A-re f2.) (3170 633i' 5Z5 F73 i-L r1ir -c-c ric1/j e,+rS Trash Storage Areas SD-32 Design Objectives Maximize Infiltration Provide Retention Slow Runoff Minimize Impervious Land coverage Prohibit Dumping of Improper Materials contain Pollutants Collet and Convey Description Trash storage areas are areas where a trash receptacle (s) are located for use as a repository for solid wastes. Stormwater runoff from areas where trash is stored or disposed of can be polluted. In addition, loose trash and debris can be easily transported by water or wind into nearby storm drain inlets, channels, and/or creeks Waste handling operations that maybe sources of stormwater pollution include dumpsters, litter control, and waste piles. Approach This fact sheet contains details on the specific measures required to prevent or reduce pollutants in stormwater runoff associated with trash storage and handling. Preventative measures including enclosures, containment structures, and impervious pavements to mitigate spills, should be used to reduce the likelihood of contamination. Suitable Applications Appropriate applications include residential, commercial and industrial areas planned for development or redevelopment (Detached residential single-family homes are typically excluded from this requirement.) Design Considerations Design requirements for waste handling areas are governed by Building and Fire Codes, and by current local agency ordinances and zoning requirements The design criteria described in this fact sheet are.meant to enhance and be consistent with these .code and ordinance requirements. Hazardous waste should be handled in accordance with legal requirements established in Title 22, California Code of Regulation. Wastes from commercial and industrial sites are typically hauled by either public or commercial carriers that may have design or access requirements for waste storage areas The design criteria in this fact sheet are recommendations and are not intended to be in conflict with requirements established by the waste hauler. The waste hauler should be contacted prior to the design of your site trash collection areas Conflicts or issues should be discussed with the local agency. Designing New Installations Trash storage areas should be designed to consider the following structural or treatment control BMPs: Design trash container areas so that drainage from adjoining I roofs and pavement is diverted around the area(s) to avoid run-on. This might include henning or grading the waste handling area to prevent run-on of stormwater. I • Make sure trash container areas are screened or walled to prevent off-site transport of trash. 7 January 2003 California Stormwater BMP Handbook 1 of 2 New Development and Redevelopment www.cabmphandbooks.com SD-32 Trash Storage Areas a Use lined bins or dumpsters to reduce leaking of liquid waste. Provide roofs, awnings, or attached lids on all trash containers to minimize direct precipitation and prevent rainfall from entering containers- Pave, trash storage areas with an impervious surface to mitigate, spills. a Do not locate storm drains in immediate vicinity of the trash storage area. a Post signs on all dumpsters informing users that hazardous materials are not to be disposed Of therein. Redeveloping Existing Installations Various jurisdictional stormwater management and mitigation plans (SUSMP, WQMP,, etc..) define "redevelopment" in terms of amounts of additional impervious area, increases in gross floor area and/or exterior construction, and land disturbing activities with structural or impervious surfaces The definition of" redeelopment" must be consulted to determme whether or not the requirements for new development apply to areas intended for redevelopment lithe definition applies, the steps outlined under "designing new installations" above should be followed. Additional Information Maintenance Considerations The integrity of structural elements that are subject to damage (i.e., screens, covers, and signs) must be maintained by the owner/operator. Maintenance agreements between the local agency and the owner/operator may be required Some agencies will require maintenance deed restrictions to be recorded of the property title If required by the local agency, maintenance agreements or deed restrictions must be executed by the owner/operator before improvement plans are approved. Other Resources A Manual for the Standard Urban Stormwater Mitigation Plan (SUSMP), Los Angeles County Department of Public Works, May 2002 Model Standard Urban Storm Water Mitigation Plan (SUSMP) for San Diego County, Port of San Diego, and Cities in San Diego County, February 14, 2002. Model Water Quality Management Plan (WQMP) for County of Orange, Orange County Flood Control District, and the Incorporated Cities of Orange County, Draft February 2003 Ventura Countywide Technical Guidance Manual for. Stormwater Quality Control Measures, July. 2002. 2 of 2 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Targeted Constituents Sediment A Nutrients Trash Ea Metals A El Bactena 01! and Grease A Organics A Legend (Removal Effectiveness) Low U High A Medium Vegetated Swale TC-30 iI Description Vegetated swales are open, shallow channels with vegetation covering the side slopes and bottom that collect and slowly convey runoff flow to downstream discharge points- They are desig:ied to treat 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 meta), promote infftration, and reduce the flow velocity of storniwater runoff. Vegetated swales can serve as part of a stormwater drainage system and can replace curbs, gutters and storm sewer systems. California Experience Caltrans constructed and monitored six vegetated swales in southBrn California. These swales were generally effective in reducing the volume and mass of pollutants in runoff. Even in the areas where the annual rainfall was only about 10 mches/yr, the vegetation did not require additional irrigation. One factor that strongly affected performance was the presence of large numbers of gophers at most of the sites. The gophers created earthen mounds, destroyed vegetation, and generally reduced the effect- veness of the controls for TSS reduction. Advantages If properly designed, vegetated, and operated, swales can serve as an aesthe:ic, potentially inexpensive urban development or rc adwav drainage conveyance measure with significant collateral water quality benefits. Design Considerations Tributary Area Area Required Slope Water Availability EASQ January 2003 California Stormwater BMPbandbcok I of 13 New Development and Redeveloprrerit www.cabmphandbooks. corn TC-30 Vegetated Swale Roadside ditches should be regarded as significant potential swale/buffer strip sites and should be utilized for this purpose whenever possible. 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. a In some places, their use is restricted by law: many local municipalities require curb and gutter systems in residential areas. Swales are mores susceptible to failure if not properly maintained than other treatment BMPs. Design and Sizing Guidelines Flow rate based design determined by local requirements or sized so that 85% of the annual runoff volume is discharged at less than the design rainfall intensity. Swale should be designed so that the water level does not exceed 2/3rd5 the height of the grass or 4 inches, which ever is less, at the design treatment rate. Longitudinal slopes should not exceed 25% a Trapezoidal channels are normally recommended but other configurations, such as parabolic, can also provide substantial water quality improvement and may be easier to mow than designs with sharp breaks in slope. a Swales constructed in cut are preferred, or in fill areas that are far enough from an adjacent slope to minimize the potential for gopher damage. Do not use side slopes constructed of fill, which are prone to structural damage by gophers and other burrowing animals. A diverse selection of low growing, plants that thrive under the specific site, climatic, and watering conditions should be specified. Vegetation whose growing season corresponds to the wet season are preferred. Drought tolerant vegetation should be considered especially for swales that are not part of a regularly irrigated landscaped area. The width of the swale should be determined using Manning's Equation using a value of 0.25 for Manning's n. I 2 of 13 California Stormwater BMP Handbook January 2003 New Development and Redevelopment - www.cabmphandbooks.com I I I I I I I I I I I I I I I I I I I Vegetated Swale TC-30 Construction/Inspection Considerations Include directions in the specifications for use of appropriate fertilizer and soil amendments based on soil properties determined through testing and compared to the needs of the vegetation requirements. Install swales at the time of the year when there is a reasonable chance of successful establishment without irrigation, however, it is recognized that rainfall in a given year may not be sufficient and temporary irrigation may be used. If sod tiles must be used, they .should be.pllaced so that there are no gaps between the. tiles; stagger the ends of the tiles to prevent the formation of channels along the swale or strip Use a roller on the sod to ensure thatno air pockets form between the sod and the soil. Where seeds are used, erosion controls will be necessary to protect seeds for at least 75 days after the first rainfall of the season. Performance The literature suggests that vegetated swales represent a practical and potentially effective technique for controlling urban runoff quality. While limited quantitative performance data exists for vegetated swales, it is known that check dams, slight slopes, permeable soils, dense grass cover, increased contact time, and small storm events all contribute to successful pollutant removal by the swale system. 'Factors decreasing the effectiveness of swales include compacted soils, short runoff contact time, large storm events, frozen ground, short grass heights, steep slopes, and high runoff velocities and discharge rates. Conventional vegetated swale designs have achieved mixed results in. removing particulate pollutants A study performed by the Nationwide Urban Runoff Program (NURP) monitored three grass swales in the Washington, D.C., area and found no significant improvement in urban runoff quality for the pollutants analyzed However, the weak performance of these swales was attributed to the high flow velocities in the swales, soil compaction, steep slopes, and short grass height Another project in Durham,. NC, monitored the performance Of .a carefully designed artificial swale that received runoff from a commercial parking lot The project tracked ii storms and concluded that particulate concentrations of heavy metals (Cu, Pb, Zn, and Cd) were reduced by approximately 50 percent However, the swale proved largely ineffective for removing soluble nutrients. The effectiveness of vegetated swales can be enhanced by adding, check dams at approximately 17 meter (50 foot) increments along their length (See Figure i) These dams maximize the retention time within the swale, decrease flow velocities, and promote particulate settling. Finally, the incorporation of vegetated filter strips parallel to the top of the channel banks can help to treat sheet flows entering the swale. Only 9 studies have been conducted on all grassed channels designed for water quality (Table 1)- The data suggest relatively high removal rates for some pollutants, but negative removals for some bacteria, and fair performance for phosphorus. January 2003 California Stormwater BMP Handbook 3 of 13 New Development and Redevelopment www.cabmphandbooks.com TC-30 Vegetated Swale Table 1 Grassed swale pollutant removal efficiency data Removal Efficiencies (% Removal) Study TSS TP TN NO3 Metals Bacteria Type Caltrans '2002 77 8 67 66 83-90. -33 dry swales Goldberg 1993 678 45 - 314 42-62 -100 grassed channel Seattle Metro and Washington Department of FIo 1992 6o 45 - -25 2-16 -25 grassed channel Seattle Metro and Washington Department of Ecology, 1992 83 29 - -25 46-73 -25 grassed channel Wang et al., 1981 8o - - - 70-80 - dry swale Dorman'etal.,.1989 .98 :18 45 37-81 - diyswale Harper, 1988 87 83 84 8o 88-90 - dry swale Keicher et al, 1983 99 99 99 99 99 - dry swale Harper, 1988 81 17 40 52 37-69 - et swale Koon, 1995 67 39 - 9 -3510 6 - wet swale While it is difficult to distinguish between different designs, based on the .small ..amount of available data, grassed channels generally have poorer removal rates than wet and dry swales, although some swales appear to export soluble phosphorus (Harper, 1988, Koon, 1995) It is not clear why swales export bacteria One explanation is that bacteria thrive in the warm swale soils. Siting Criteria The suitability of a swale at a site will depend on land use, size of the area serviced, soil type, slope, imperviousness of the contributing watershed, and dimensions and slope of the swale system (Schueler et al, 1992) In general, swales can be used to serve areas of less than 10 acres, with slopes no greater than % Use of natural topographic lows is encouraged and natural drainage courses should be regarded as significant local resources to be kept in use (Young et al, 1996) Selection Criteria (NCTCOG, 1993) Comparable performance to wet basins Limited to treating a few, acres . Availability of water during dry periods to maintain vegetation Sufficient available land area Research in the Austin area indicates that vegetated controls are effective at removing pollutants even when dormant Therefore, irrigation is not required to maintain growth during dry periods, but may be necessary only to prevent the vegetation from dying 4 of 13 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Vegetated Swale TC-30 The topography of the site should permit the design of a channel with appropriate slope and 1 cross-sectional area. Site topography may also dictate a need for additional structural controls. I Recommendations for longitudinal slopes range between 2 and 6 percent. Flatter slopes can be used, if sufficient to provide adequate conveyance Steep slopes increase flow velocity, decrease detention time, and may require energy dissipating and grade check Steep slopes also can be I managed using a series of check dams to terrace the swale and reduce the slope to within acceptable limits The use of check dams with swales also promotes infiltration Additional Design Guidelines Most of the design guidelines adopted for swale design specify a minimum hydraulic residence time of 9 minutes This criterion is based on the results of a single study conducted in Seattle, ' Washington (Seattle Metro and Washington Department of Ecology, 1992), and is not well supported Analysis of the data collected in that study indicates that pollutant removal at a residence time Of ,5 minutes was not significantly different, although there is more variability ia that data Therefore, additional research m the design criteria for swales is needed Substantial pollutant removal has also been observed for vegetated controls designed solely for conveyance (Barrett et al, 1998), consequently, some flexibility in the design is warranted I Many design guidelines recommend that grass be frequently mowed to. maintain dense coverage near the ground surface Recent research (Colwell et al, 2000) has shown mowing frequency or -i grass height has little or no effect on pollutant removal Summary of Design Recommendations i) The swale should have a length that provides a minimum hydraulic residence time of I at least 1.0 minutes. The maximum bottom width should not exceed 10 feet unless a dividing berm is provided The depth of flow should not exceed 2/3rds the height of the grass at the peak of the water quality design storm intensity. The channel slope I should not exceed 2.5%. A design grass height Of 6 inches is recommended. 1 Regardless of the recommended detention time, the swale should be.,not less than 100 feet in length. I 4) The width of the swale should be determined. using Manning's .Equation, at .the peak of the design storm, using a Mairning's ii of 0.25. I The swale can be sized as both a treatment facility for the design storm and as a conveyance system to pass the peak hydraulic flows of the 100-year storm if it as located "on-line." The side .slopes should be no steeper than :i (H:V. Roadside ditches should be regarded as significant potential swale/buffer strip sites and should be utilized for this purpose whenever possible. If flow is to be:introduced I through curb cuts, place pavement slightly above the elevation of the vegetated areas Curb cuts should be at least 12 inches wide to prevent clogging. Swales must be vegetated in order to provide adequate treatment of rnnoff. It is important to maximize water contact with vegetation and the soil surface. For -general purposes, select fine, close-growing, water-resistant grasses. If possible, divert runoff (other than necessary irrigation) during the period of vegetation January 2003 California Stormwater BMP Handbook 5 of 13 New Development and Redevelopment www.cabmphandbooks.com TC-30 Vegetated Swale establishment. Where runoff diversion is not possible, cover graded and seeded areas with suitable erosion control materials. Maintenance The useful life of a vegetated Swale system is directly proportional to its maintenance frequency. If properly designed and regularly maintained, vegetated swales can last indeflmtely. The maintenance objectives for vegetated swale systems include keeping up the hydraulic and removal efficiency of the channel and maintaining a dense, healthy grass cover. Maintenance activities should include periodic mowing (with grass never cut shorter than the design flow depth), weed control, watering during drought conditions, reseeding of bare areas, and clearing of debris and blockages. Cuttings should be removed from the channel and disposed m a local composting facility Accumulated sediment should also be removed 1. manually to avoid concentrated flows in the Swale.The application of fertilizers and pesticides should be minnnal Another aspect of a goodmaintenance plan is. repairing damaged areas within..a channel For example, if the channel develops ruts or holes, it should be repaired utilizing, a suitable soil that is properly tamped and seeded The grass cover should be thick, if it is not, reseed as necessary Any standing water removed during the maintenance operation must be disposed to a sanitary sewer at an approved discharge location Residuals (e g, silt, grass cuttings) must be disposed in accordance with local or State requirements Maintenance of grassed swales mostly involves maintenance of the grass or wetland plant cover. Typical maintenance activities are summarized below Inspect swales at least twice annually for erosion, damage to vegetation, and sediment and debris accumulation preferably at the end of the wet season to schedule summer maintenance and before major fall runoff to be sure the swale is ready for winter- However, additional inspection, after periods of heavy runoff is desirable The swale should be checked for debris and lifter, and areas of sediment accumulation. Grass height and mowing frequency may not have a large impact on pollutant removal. Consequently, mowing may only be necessary once or twice a year for safety or aesthetics or to suppress weeds and woody vegetation. a Trash tends to accumulate in swàle areas, particularly along highways. The need for litter removal is determined through periodic inspection, ,but litter should always be removed prior to mowing Sediment accumulating near culverts and in channels should be removed when it builds up to 75 mm (3 in.) at any spot, or, covers vegetation. Regularly inspect swales for pools of standing water. Swales can become a nuisance due to mosquito breeding in standing water if obstructions develop (e.g. debris accumulation, invasive vegetation) and/or if proper drainage slopes are not implemented and maintained 6 of 13 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com I Vegetated Swale TC-30 1 Cost I Construction Cost Little data is available to estimate the difference in cost between various swale designs. One study (SWRPC, 1991) estimated the construction cost of grassed channels at approximately $0.25 per W. This price does not .include design costs or contingencies Brown and Schueler (1997) estimate these costs at approximately 32 percent of construction costs for most storinwater management practices For swales, however, these costs would probably be significantly higher since the construction costs are so low compared with other, practices. A more realistic estimate would be a total cost of approxunately $o 50 per ft2, which compares favorably with other stormwater management practices. I I I I I I I 1 I I 1 1 January 2003 California Storrnwater BMP Handbook 7 of 13 I New Development and Redevelopment ww.cabmphandbQokscom -M - - TC-30 Vegetated Swale Table 2 Swale cost Estimate: (SEWRPc, 1991) Unit Cast Total Cost Low Moderate High Low Moderate High Component Unit Extant Mobilization / Swab I $107 $274 $441 $107 $274 $441 DornobUizationUght Site Preparation Clearing' Acre 05 $2,206 0,800 $5,400 $1 100 $1,400 $2,700 Grubbingc Acre u5 $3,800 $5,200 $6,600 $950 $1,300 $1,650 General YCP 372 52.10 $170 $5.30 $781 .$11376 .$1.972 Level and Tilla ....... . Yd 1210 $0.20 $035 $050 $242 $424 $605 Sites Dove Salva god Topsoil Seed and Mulch!.. Y12 1,210 $040 $1 00 $160 $484 $1,210 $1 936 sodg YIP 1,210 $1.20 $2,40 $360 $1,452 $2,904 $4368 Subtotal - -- - $5116 $9385 $13680 Contingencies. Swats 1 25%: 25% 25%I $1279 $2,347 $3,415 Tot -- - - --$6,395 $11735 $17,075 Source: (SEWRPG, 1991) Nate: Mobiflzalion/dernobilization refers to the organization and planning invoivédin establishing, of vetabvéswaba Swale has a bottom width of 1.0 foot a top width of 10 feet wit 1 3 sIde slopes and a 1,000-loot length 'Area cleared ..= (top width +10 tet)x swale length Area grubbed = (top width x swale length) dVolume. caved = (0,67 x top widthx swabs depth) x swats length (parabolic cross section) Area ti lied =(top Width + 8(swala depth) xswale length (parabolic crossectlon). 3(top width) 'Area seeded =area cleared x 0 5 Area sodded, = area cleared x 0.5; 8 of 13 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www cabmphandbooks corn M- — — — — — — — - M. _J - - - - - - M. M. Vegetated SaIe . . . . . T.C-30 Table 3 Estimated. Maintenance Costs. (SEWRPC, 1991) Swale Size. .(Depth and Top •Wklth) Component Unit Cost . 1.5 Foot Depth, One- 3-Foot bpth, 3-Foot Comment Foot Bottom Width, Bottom Width, 21-Foot 10-Foot Top Width Top Width Lawn Mowing $0.5 / 1,000 ft2/ incmng $0.14 / Hn as rfoot $0.21 1 Ii near foot Lawn maintenance ar=(iep width + lO feat) x length. Mow eight times per ya& General Lawn Cara $9.00/1,000 ft/yoar $0.18/Iinrfoot $0.28./11naarfoot Lawn maintenance area = (top width+ 10 foot) xlength Swale Deb risand Uttar $0.10 /linaár foot! year $010 /linaaifoot $0.10 /li hear foot - Removal Grass Reseeding with $030 / yd2 $0.011 linearfoot $0.01 /linear foot Area ravagotatod equals 1% Mulch and Fertilizer ofiawnrnaintanancaaraa par year Program Administration and $0.15! linoarfoot I.yaar, $0.15 / linaar.foot $0.15 /linèar foot Inspect four times par year Swale Inspection plus $251 insp9cbon Total - $038/Iinoárfoot $0J51linoarfoot January 2003 California Stormwater BMP HandbOk. 9 of 13 New Development andRedevelopment www.cabrnphandbooks.com TC-30 Vegetated Swale Maintenance Cost Caltrans (2002) estimated the expected annual maintenance cost for a swale with a tributary area of approximately 2 ha at approximately $2,700. Since almost all maintenance consists of mowing, the cost is fundamentally a function of the mowing frequency. Unit costs developed by SEWRPC are shown in Table 3. In many cases vegetated channels would be used to convey runoff and would require periodic mowing as well, so there maybe little additional cost for the water quality component Since essentially all the activities are related to vegetation management, no special training is required for maintenance personnel References and Sources: of Additional Information Barrett, Michael E., Walsh, Patrick M., Malina, Joseph F., Jr., Charbeneau, Randall J, 1998, "Performance of vegetative controls for treating highway runoff," ASCE Journal of Environmental Engineering, Vol 124, Now ii, pp 1121-1128 Brown, W., and T. Schueler. 1997. The Economics of Storm water BMPs in the Mid-Atlantic. Region Prepared for the Chesapeake Research Consortium, Edgewater, MD, by the Center for Watershed Protection, Ellicott city, MD. Center for Watershed Protection (cWP). 1996. Design of Storm water Filtering Systems, Prepared for the Chesapeake Research Consortium, Solornons, MD, and USEPA Region V, Chicago, IL, by the Center for Watershed Protection, Ellicott City, MD coiwéll, Shanti R., :Horner, Richard It, and Booth, Derek B., 2000. Characterization of Performance Predictors and Evaluation ofMowing Practices in Biofiltration Swales Report to King County Land And Water Resources Division and others by Center for Urban Water. Resources Management, Department of Civil and Environmental Engineering, University of Washington, Seattle, WA Dorman, M.E., J. Hartigan, R.F. Steg, and T. Quasebarth. 1989. Retention, Detention and Overland Flow for Pollutant Removal From Highway Stormwater Runoff Vol 1 FHWA/RD 89/202.,Federal Highway Administration, Washington, DC Goldberg. 1993. Dayton Avenue Swale Biofiltration Study. Seattle Engineering Department, Seattle, WA. Harper, H. 1988. Effects of StormwaterMazagemênt Systems on Groundwater Quality. Prepared for Florida Department of Environmental Regulation, Tallahassee, FL, by Environmental Research and Design, Inc., Orlando, FL. Kercher,W.C., J.C. Landon, and R. Massarelli. 1983- Grassy swales prove cost-effective for water pollution control- Public Works, 16: 53-55. Koon, J. 1995. Evaluation of Water Quality Ponds and Swales in the Issaquah/East Lake Samnmamish Basins King County Surface Water Management, Seattle, WA, and Washington Department of Ecology, Olympia, WA. Metzger, M. E., D. K Messer, C. L. Beitia, C. M. Myers, and V. L. Kramer, 2002. The Dark Side Of Stormwater Runoff Management: Disease Vectors Associated With Structural BMPs. Stormnwater .3(2): 24-39.Oakland, P.H. 1983. An evaluation of stormwater pollutant removal 10 of 13 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com I Vegetated Swale TC-30 through grassed swale treatment. In Proceedings of the International Symposium of Urban I .Hydrology, Hydraulics and Sediment Control, Lexington, KY pp. 173-182. Occoquan Watershed Monitoring Laboratory. 1983- Final Report: Metropolitan Washington Urban Runoff Project Prepared for the Metropolitan Washington Council of Governments, I Washington, DC, by the Occoquan Watershed Monitoring, Laboratory, Manassas, VA. Pitt, R, and J. McLean. 1986. Toronto Area Watershed Management Strategy Study: Humber River Pilot Watershed Project. Ontario Ministry of Environment, Toronto, ON. Schueler, T. 1997. Comparative Pollutant Removal Capability of Urban BMPs: A reanalysis. 1 Watershed Protection Techniques. 2(2):379-383. Seattle Metro and Washington Department of Ecology. 1992. Biofiltration Swale Performance: Recommendations and Design Considerations Publication No 657 Water. Pollution Control I Department, Seattle, WA. Southeastern Wisconsin Regional Planning Commission (SWRPC) 1991 Costs of Urban I Nonpornt Source Water Pollution Control Measures Techmcal report no 31 Southeastern Wisconsin Regional Planning Commission, Waukesh,•WI. U.S. EPA, 1999, Stormwater Fact Sheet: Vegetated Swales, Report # 832-F-99-006 I .http: //w.epa.gov/owm/mtb/vegswale.pdf, Office of Water, Washington DC. I Wang, T., D. Spyridakis, B. Mar, and R. Homer. 1981. Transport, Deposition and Control of Heavy Metals in Highway Runoff FHWA-WA-RD-39-l0 University of Washington, Department of Civil Engineering, Seattle, WA. I Washington State Department of Transportation, 1995, Highway RunoffManual , Washington State Department of Transportation, Olympia, Washington I Welborn, C, and J Veenhuis 1987 Effects of Runoff controls on the Quantity and Quality of Urban Runoff in Two Locations in Austin, 1X. USGS Water Resources Investigations Report No. 87-4004. U.S. Geological Survey, Reston, VA. I Yousef, Y., M. Wanielista, H. Harper, D. Pearce, and R. Tolbert. 1985. Best Management Practices: Removal of Highway Contaminants By ROadside Swales. University of entral I Florida and Florida Department of Transportation, Orlando, FL. Yu, S., S. Barnes, and.V.Gerde. 1993. Testing of Best Management Practices for Controlling I Highway Runoff. FHWA/VA-93-R16. Virginia Transportation Research Council, Charlottesville, VA. Information Resources Maryland Department of the Environment (MDE). 2000. Maryland Storruwater Design Manual. .nide.state.md.us/environment/wrna/storrnwatermanual. Accessed May 22, 2001. Reeves, E. 1994. Performance and Condition of Biofliters in the Pacific Northwest. Watershed Protection Techniques 1(3):117-119. January 2003 California Stormwater BMP Handbook 11 of 13 New Development and Redevelopment www.cabmphandbooks.com TC-30 Vegetated Swale Seattle Metro and Washington Department of Ecology. 1992. Bioflltration Swale Performance. Recommendations and Design Considerations. Publication No 657. Seattle Metro and Washington Department of Ecology, Olympia, WA. USEPA.1993. Guidance Specfy.ing Management Measuresfor Sources ofNonpoint Pollution in Coastal Waters. EPA-840-B-2-002. U.S. Environmental. Protection Agency, Office of Water. Washington, DC. Watershed Management Institute(WMI). 1997. Operation, Maintenance, and Management of Stormwater Management Systems. Prepared for U.S- Environmental Protection Agency, Office of Water Washington, DC, by the Watershed Management Institute, Ingleside, MD 12 of 13 clifornia Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com I I I I I I I I Vegetated Swale T•C-30 - - L ) Crm3 wthwt of cwafr with check dam. PM 1 Notation. I. = LongUi of.swjlo Impomilmont aroa per sfn,ok darn (fl) (b) Depth of chock d,,-4p ft) Bottom slp of swata (ft'ft W = Top width of chock darn (ft) Bottom width of chock darn (ft) Rotro of hortzontal to voitrct oltanga In swata side slope #VM I I Din nhlannlsic* of %OaI( lfllpoundnutnl nri.. I I I i I January 2003 California Stormwater BMP Handbook 13 of 13 New Development and Redevelopment www.cabmphandbooks.com R 1~ ~ BF CONSULTING PLANNING U DESIGN • CONSTRUCTION 80.479.380S • WWW,.RBFCcIM JOB SHEET NO I OF CALCULATEDBY EJi) DATE CHECKED BY DATE SCALE I I I I I I I I I I I 1 I I I I I e \ ( ç bqc1 dri r'---ev'# ',4( 3- 62 ,/hr (c,4sc,4 Lk) Dr Ie Ar 1 01 4 {per; A1h'i c. Aff'ol zz e,&S 4 rtS c'Z ciA 2. 0, 1 q c.S A-MAI 0,2c,trQ 1 C'9S s (.z '/&ir)(,)' s I sk max 0.2 LI C ' (e e 4ei'j 02 > iq 4*I eS prvI'l eVL4 -reA:$ieri+ I I Highlighted Depth (ft) = 0.50 Q(cfs) = 0.241 Area (sqft) = 075 Velocity (fits) = 0 32 Wetted Perim (It) = 316 Crit Depth, Yc (ft) = 0.19 Top Width (ft) = 3.00 EGL(ft) = 0.50 2. o 2 I Thursday Aug 28 2008 Channel Report Hydraflow Express by Intelisolve Planning Area I - Grass Swale Triangular Side Slopes (z:1) = 3.00, 3.00 Total Depth (ft) = 0.50 Invert Elev (ft) = 1 00 Slope (%) = 2.00 NVa]ue = 0 250 Calculations Compute by: Q vs Depth No, Increments = 10 Elev (ft) 200---- 1.75 150 1.25 1.00 Section 075 - 0 5 1 15 2 25 3 35 Reach (ft) Targeted Constituents El Sediment A El Nutnents Ed trash El Metals S Bacteria El Oil and Grease El Organics Legend (Removal Effectiveness) Low U High A Medium I Vortex Separator MP-51 I Description Design Considerations Vortex separators: (alternatively, swirl concentrators) are gravity separators, and in principle are essentially wet vaults. The difference from wet vaults, however, is that the vortex separator is round, rather than rectangular, and the water moves in a centrifugal fashion before exiting. By having the water move in a circular fashion, rather than a straight line as is the case with a standard wet vault, it is possible to obtain significant removal of suspended sediments and attached pollutants with less space. Vortex separators were originally developed for combined sewer overflows (CSOs), where it is used primarily to remove coarse inorganic solids. Vortex separation has been adapted to stormwater treatment by several manufacturers. California Experience There are currently about 100 installations in California. Advantages May provide the desired performance in less space and therefore less cost. May be more cost-effective devices than pre-treatment traditional wet or dry basins. Mosquito control may beless 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 indiameterand less. . The area served is limited by the capacity of the largest models. As the products come in standard sizes, the facilities will be oversized in many cases relative to the design treatment storm, increasing the cost. The non-steady flows of stormwater decreases the efficiency I of vortex separators from what maybe estimated or determined from testing under constant flow. I • Do not remove dissolved pollutants. I Service Area Settling Velocity Appropriate Sizing Inlet Pipe Diameter I January2003 California Stormwater BMP Handbook 1 of 5 New Development and Redevelopment www.cabmphandbooks.com MP-51 Vortex Separator A loss of dissolved pollutants may occur as accumulated organic matter (e.g., leaves) decomposes in the units Design and Sizing Guidelines The stormwater enters, typically below the effluent line, tangentially into the basin, thereby imparting a circular motion an the system Due to centrifugal forces created by the circular motion, the suspended particles move to the center of the device where they settle to the bottom. There are two general types of vortex separation free vortex and dampened (or impeded) vortex Free vortex separation becomes dampened vortex separation by the placement of radial baffles .on the weir-plate that impede the free vortex-flow pattern It has been stated with respect to CSOs that the practical lower limit of vortex separation is a particle with a settling velocity of 12 to 1.6 .5 feet per hour (o 10 to 0.14 cm/s) As such, the focus for vortex separation in CSOs has been with settleable solids generally 200 microns and larger, given the presence of the lighter organic solids For inorganic sediment, the above settling velocity range represents a particle diameter of o to 100 microns Head loss is a function of the size of the target particle. At 200 microns it is normally minor but increases significantly if the goal is to remove smaller particles. The commercial separators applied to stormwater treatment vary considerably with respect to geometry, and the inclusion of radial baffles and internal circular chambers. At oneextremeis the inclusion of a chamber within the round concentrator Water flows initially around the perimeter between the inner and outer chambers, and then into the inner chamber, giving rise to a sudden change in velocity that purportedly enhances removal efficiency. The opposite extreme is to introduce the water tangentially into a round manhole with no internal parts of any kind except for an outlet hood Whether the inclusion of chambers and baffles gives better performance is unknown Some contend that free vortex, also identified as swirl concentration, creates less turbulence thereby increasing removal efficiency. One product is unique in that it includes a static separator screen. Sized is based on the peak flow of the design treatment event as specified by local government. If an in-line facility, the design peak flow is four times the peak of the design treatment event. If an off-line facility, the design peak flow is equal to the peak of the design treatment event. Headloss differs with the product and..the model but is generally on the order of one foot or less in most cases. Construction/inspection Considerations No special considerations. Performance Manufacturer's differ with respect to performance daims, but a general statement is that the manufacturer's design and rated capacity (cfs) for each model is based on and believed to achieve an aggregate reduction of 90% of all particles with a specific gravity of 265 (glacial sand) down to 150 microns, and to capture the .floatables, and oil and grease. Laboratory tests of 2 of 5 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com I Vortex Separator MP-51 two products support this claim. The stated performance expectation therefore implies that a lesser removal efficiency is obtained with particles less than 150 microns, and the lighter, I organic settleables. Laboratory tests of one of the products found about 60% removal of 50 micron sand at the expected average operating flow rate Experience with the use of vortex separators for treating combined sewer overflows (CSOs), the original application of this technology, suggests that the lower practical limit for particle removal are particles with a settling velocity of 12 feet per. hour (Sullivan, 1982), which I represents .a particle diameter of 100 to 200 microns, depending on the specific gravity of the particle. The CSO experience therefore seems consistent with the limited experience with treating stormwater, summarized above I Traditional treatment technologies such as wet ponds and extended detention basins are generally believed to be more effective at removing very small particles, down to the range of 10 to 20 microns Hence, it is intuitively expected that vortex separators do not perform as well as the traditional wet and dry basins, and filters. Whether this matters depends on the particle size distribution of the sediments in stormwater. If the distribution leans towards small material, there should be a marked difference between vortex separators and, say, traditional wet vaults 1 There are little data to support this conjecture In comparison to other treatment technologies, such as wet ponds and grass swales, there aie I few studies of vortex separators Only two of manufactured products currently, available have been field tested Two field studies have been conducted Both achieved in excess of 8o% removal of TSS However, the test was conducted in the Northeast (New York state and Maine) I where it is possible the stormwater contained significant quantities of deicing sand. Consequently, the influent TSS concentrations and particle size are both likely considerably higher than is found in California stormwater. These data suggest that if the stormwater I particles are for the most part fine (i e., less than 50 microns), vortex separators will not be as efficient as traditional treatment BM Ps such as wet ponds and swales, if the latter are sized according to the recommendations of this handbook. I There are no equations that provide .a straightforward determination of efficiency as a:function of unit configuration and size Design specifications of commercial separators are derived from empirical equations that are unique and proprietary to each manufacturer. However, some general relationslups between perforniance and the geometry of a separator have been developed CSO studies have found that the primary determinants of performance of vortex separators are the diameters of the inlet pipe and chamber with all other geometry proportional I to these two. Sullivan et al. (1982) found that performance is related to the ratios of chamber to inlet I diameters, D2/D1, and height between the inlet and outlet and the inlet diameter, Hi/Di, shown in Figure 3 The relationships are as D2/D1 approaches one, the efficiency decreases, and, as the Hi/Di ratio decreases, the efficiency decreases These relationships may allow qualitative I comparisons of the alternative designs of manufacturers. Engineers who wish to apply these concepts should review relevant publications presented in the References. Siting Criteria There are no particularly unique siting criteria. The size of the drainage area that can be served by vortex separators is directly related to the capacities of the largest models. I January 2003 California Storrnwater BMP Handbook 3 of 5 I New Development and Redevelopment www.cabmphandbooks.com MP-51 Vortex Separator Additional Design Guidelines Vortex separators have two capacities if positioned as in-line facilities, a treatment capacity and a hydraulic capacity. Failure to recognize the difference between the two may lead to significant under sizing; i.e., too small a model is selected This observation is relevant to three of the five products These three technologies all are designed to experience a unit flow rate of about 24 gallons/square foot of separator footprint at the peak of the design treatment event. This is the horizontal area of the separator zone within the container, not the total footprint of the unit At this unit flow rate, laboratory tests by these manufacturers have established that the performance will meet the general claims previously described. However, the units are sized to handle 100 gallons/square foot at the peak of the hydraulic event Hence, in selecting a particular model the design engineer must be certain to match the peak flow of the design event to the stated treatment capacity, not the hydraulic capacity. The former . is one-fourth the latter. If the unit is positioned as an off-line facility, the model selected is based on the capacity equal to the peak of the design treatment event. Maintenance Maintenance consists of the removal of accumulated material with an eductor truck. It may be necessary to remove and dispose the floatables separately due to the presence of petroleum product. Maintenance Requirements Remove all accumulated sediment, and litter and other floatables, annually, unless experience indicates the need for more or less frequent maintenance. Cost Manufacturers provide costs for the units including delivery. Installation costs are generally on the order Of 50 to j.00% Of the manufacturer's cost. For most sites the units are cleaned. annually. Cost Considerations The different geometry of the several manufactured separators suggests that when comparing the costs of these systems to each other, that local conditions (e g , groundwater levels) may affect the relative cost-effectiveness References and Sources of Additional Information Field, R, 1972, The swirl concentrator as a combined sewer overflow regulator facility, EPA/R2- 72-008, U.S. Environmental Protection Agency, Washington,. D.C. Field, R., D. Averill, T.P. O'Connor, and?. Steel, 1997, Vortex separation technolor, Water Qual. Res. J. Canada, 32, 1,185 Manufacturers. technical materials Sullivan, R.H., et al., 1982, Design manual - swirl and helical bend pollution control devices, EPA-60018-82/013, U.S. Environmental Protection Agency, Washington, D.C. Sullivan, R.H., M.M. Cohn, J.E. Ure, F.F. Parkinson, and G. Caliana, 1974, Relationship between diameter and height for the design of a swirl concentrator as a combined sewer overflow regulator, EPA 670/2-74-039, U.S. Environmental Protection Agency, Washington, D.C. 4 of 5 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com I Vortex Separator MP-51 Sullivan, R.H., M.M. Cohn, J.E. Ure, F.F. Parkinson, and G. Caliana, 1974, The swirl concentrator as a grit separator device, EPA670/2-74-026, U.S. Environmental Protection I Agency, Washington, D.C. Sullivan, R.11, M.M. Cohn, J.E. Ure, F.F. Parkinson, and G. Caliana, 1978, Swirl primary I separator device and pilot demonstration, EPA600/2-78-126, U.S. Environmental Protection Agency, Washington, D.C. I I I I I I I I I 1 I I I January, 2003 California Stormwater BMP Handbook 5 of 5 New Development and Redevelopment www.cabmphandbooks.com Targeted Constituents El Sediment El Nutrients El Trash El Metals Bacteria .El Oil and Grease El Organics Removal Effectiveness See New Deveioprnent.and Redevelopment Handbook-Section 5. 1 of 3 1 Drain Inserts ji Description Drain inserts are manufactured filters or fabric placed in a drop I inlet to remove sediment and debris. There are a multitude of inserts of various shapes and configurations, typically falling into one of three different groups: socks, boxes, and trays. The sock I consists of a fabric, usually constructed of polypropylene. The fabric may be attached to a frame or the grate of the inlet holds I 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 the form of the box. Most box products are one box; that is, the setting area I and filtration through media occur in the same box. Some products consist of one or more trays or mesh grates. The trays may hold different types of media- Filtration media vary by I manufacturer. Types include polypropylene, porous polymer, treated cellulose, and activated carbon. I California Experience The number of installations is unknown but likely exceeds a, thousand Some users have reported that these systems require I considerable maintenance to prevent plugging and bypass. Advantages Does not require additional space as inserts as the drain Ia inlets are already a component of the standard drainage systems. I • Easy access for inspection and maintenance. As there is no standing water, there is little concern for I mosquito breeding. A relatively inexpensive retrofit option. I 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 suitable for large areas, or areas with trash or leaves than can plug the insert. I I I I I Design and Sizing Guidelines Refer to manufacturer's guidelines. Drain inserts come any many configurations but can be placed into three general 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 the form of the box. Most 'box products are January 2003 California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbooks.com MP-52 Design Considerations Use with other BMPs . Fit and Seal Capacity within Inlet MP-52 Drain Inserts I one box; that is, the setting area and filtration through media occurs in the same box. One manufacturer has a double-box. Stormwater enters the first box where setting occurs. The stormwater flows into the second box where the filter media is located. Some products consist of one or more trays or mesh grates. The trays can hold different types of media- Filtration media vary with the manufacturer: types include polypropylene, porous polymer, treated cellulose, and activated carbon. Construction/Inspection Considerations Be certain that installation is done in a manner that makes certain that the stormwaterenters the unit and does not leak around the perimeter. Leakage between the frame of the insert and the frame of the drain inlet can easily occur with vertical (drop) inlets Performance Few products have performance data collected under field conditions. Siting Criteria It is recommended that inserts be used only for retrofit situations or as pretreatment where Other treatment BMPs presented in this section area used. Additional Design Guidelines Follow guidelines provided by individual manufacturers; Maintenance Likely require frequent maintenance, on the order of several times per year. Cost The initial cost of individual inserts ranges from less than $100 to about $2,000 The cost of using multiple units in curb inlet drains varies with the size of the inlet. Thelowcost of inserts may tend to favor the use of these systems over other; more..effective treatment BMPs However, the low cost of each unit ,mV be offset by the number of units that are required, more frequent mamtenance, and the shorter structural life (and therefore replacement). References and Sources of Additional Information Hrachovec, R, and G Minton, 2001, Field testing of a sock-type catch basin insert, Planet CPR, Seattle, Washington Interagency Catch Basin Insert Committee, Evaluation of Commercially-Available Catch Basin. Inserts for the Treatment of Storrnwàter Runoff from Developed Sites, 1995 Larry Walker Associates, June 1998, NDMP Inlet/In-Line Control Measure Study Report Manufacturers literature Santa Monica (City), Santa Monica Bay Municipal Stormwater/Urban Runoff Project - Evaluation of Potential Catch basin Retrofits, Woodward Clyde, September 24, 1998 2 of 3 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com 1 Drain Inserts MP-52 Woodward Clyde, June ii, 1996, Parking Lot Monitoring Report, Santa Clara Valley Nonpoint Source Pollution Control Program. January 2003 California Stormwater BMP Handbook 3 of 3 New Development and Redevelopment www.cabmphandbooks.com R lll~ BF CONSULTING PLANNING • DESIGN • CONSTRUCTION 8Da:479.3BIs • WWW.RBFcDM JOB S - icoz2l , SHEET NO I OF CALCULATED BY D ') DATE q //2/0 ' CHECKED BY DATE SCALE kJL -r R1s TA.TME1VT FL.0 3 I I I I I I I I I I I I I I I ZL1 ,-i- C Pr rlS4rS ei) U4' SLcde r-'J Areo to, frf [9f &JJ I,S CF.S $re'14 perV-1 (<r)'c+.cr ?"/hr (cs5c.i'A /r A,Ax A4x t re Lg't= o,;Ts'aere5 < =) •1'i 5f'f k , s .s G- C47LC L1 z 3 210 c?zS 4eA4p7191 4 A,tr >::' ,dirt c'4 2.ei cth1 "Iqc) :Z> Iy?rr4 A$ k4ie$ f1 Flo-Gard+Plus Filte installed Model No. Inlet ID fin x In) Grate OD . (In x in) Solids Storage Capacity (Cu ft) Filtered Flow . Icfs) Total Bypass . Cap. (cfs) FGP-12F .12x12 .14x14 .0.3 .0.4 2.8 FGP-1530F .15x30 .16x36 2.3 1.6 JGP-16F .16 x 16 .18 x 18 .0.8 .0.7 4.7 FGP-18F .18 x18 20 x 20 0.8 0.7 4.7 FGP-1822F 20 x 24 .18x22 2.1 .1.4 5.9 FGP-1824F .16x22 20x24 .1.5 .1.2 .5.0 FGP-1836F .18x36 .18x 40 2.3 .1.6 .6.9 FGP-2024F 20 x 24 22 x 24 1.2 .1.0 5.9 FGP-21F 22 x 22 24 x 24 2.2 .1.5 6.1 FGP-2142F 21 x42 26x42 .4.3 24 .9.1 .FGP-24F 24x24 26 x 26 22 .1.5 .6.1 FGP-2436F 24x36 24 x 40 34 2.0 .8.0 FGP-2445F 24x45 26x47 .4.4 24 9.3 FGP-2448F 24 x 48 26 x 48 4.4 24 9.3 .FGF-28F 28 x 28 .30 x 30 .2.2 .1.5 .6.3 FGP-30F .30 x 30 30 x 34 .3.6 2.0 .8.1 FGP-36F .36x36 36x40 46 2.4 9.1 FGP-3648F .36x48 .40x48 .6.8 .3.2 .11.5 .FGP48F 48x48 48x52 1 .9.5 3.9 1 .13.2 NOTES: .1. Storage capacity rullects 80% of maximum solids collection prior to inec8ng filtering bypass. 2. Fulteied flowrateincludesa safetylactorof 2. .3. Flo.Gard+Plus Catch Basin Filter inserts re ovallable in the standard sizes (see above) or In custom sizes. Cali for details on custom size Inserts, 4. Flo-Gard+Pluz filter Inserts should be used In corjurrction with a regular maintenance program. Roferto niaradadurerts recommended maintenance guidelines. .05 PATENT FLO-GARDTM+PLUS. CATCH BASIN FILTER INSERT (Frame Mount) FLAT GRATED INLET KiStar Enterprises, Inc.. Santa Rosa, CA (800) 579.8819 .O&04j I I APPENDIX C- BMP SITE PLAN I I I I I I H I I I 30 0 30 60 90 I LA COSTA RESORT & SPA SCALE "=30' PLANNING AREA I — BUILDINGS 9A, 9B, I OA-1 0 E BF 5000 AVBCA GRC*AAS, STE 260 CARLSBAD, CALFOINALN 92008 CONSULTING 7604769E3 • PAR 760.4769198 MARBF.Con, Ii I P ______ ENERAL INFORMATION EXISTING LANG USE: COMMERCIAL. PROPOSED LAID USE: COMMERCIAL. SEVERAL PLAN DESIGNATION TRAVEL/RECREATION COMMERCIAL. ADJACENT LAID USE: COMMERCIAL AND RESIDENTIAL. ALL STORM DRAIN FACILITIES SIZES AND LOCATION ARE PRELIMINARY AND SUBJECT TO FINAL I-000RS..OGT DESIGN & ACCEPTANCE OF IIYDRAILIC CALCJLATIONS BY CITY OF CARLSBAD. TOPOGRAPHY PREPARED BY VERTICAL MAPPING RESOURCE. INC. ENCH MARK A STREET CENTERLINE MONUMENT ON EL CAMINO REAL 0.88 MILES NORTHERLY FROM LA COSTA AVENUE. RECORD FROM: NORTH COUNTY VERTICAL CONTROL DATA. PAGE 184. ELEVATION: 113.122 ADJUSTED DATUM: NGVD 1929 EGAL DESCRIPTION IN THE CITY OF CARLSBAD, COUNTY OF SAN DIEGO, STATE OF CALIFORNIk LOTS 10, 11, 12. AND 16 OF LA COSTA RESORT, CARLSBAD TRACT 03-01, PER MV? 14984 RECORDED MARCH 18, 2005 PARCEL. A, CE 050025, AD.J 05-08, RECORDED SEPTEMBER 22, 2005 AS INSTRLNGNT NO. 2005-0818754 PARCEL C. CE 050027. AD.J 05-08. RECORDED SEPTEMBER 22, 2005 AS INSTRt3CNT NO. 2005-818756 PARCEL 0, CE 050028, AD,J 05-08. RECORDED SEPTEMBER 22, 2005 AS INSTRUMENT NO. 2005-818757 LANNING AREA 1 TLNDER OF LOTS 12 GROSS ACREAGE: 4.55 AC. PERCENT OF PROJECT IN STREETS 0% EARTHWORK QUANTITY ESTIMATE 13,050 C.Y CONTOUR INTERVAL 1' WNER/DEVELOPER O€VIS I'DSEA W2007 LA COSTA I, LLC 2100 COSTA GEL MAR ROAD CARLSBAD, CA 92009 lJik]TI] SITE RUNOFF WILL BE DIRECTED AWAY FROM THE TOPS OF SLOPES, AND ALL SLOPES WILL BE VEGETATED TO PROVIDE PERMANENT STABILIZATION. MEASURES WILL BE TAKEN TO EIGRJAE THE EFFICIENT APPLICATION OF WATER TO THE LANDSCAPING AND PREVENT ANY UNNECESSARY RLPJJFF FROM IRRIGATION. SEE SECTION 4.2.1.1. TIERS WILL BE NO OUTDOOR MATERIAL STORAGE AREAS ASSOCIATED WITH THE PROPOSED PROJECT. SEE SECTION 4.2.2. LEGEND EXIST. C(54T536 PROPOSED CONTOUR IMPERVIOUS PAVING POROUS PAVEMENT BUILDINGS LANDSCAPED ISLANDS VEGETATED SWALE [ PROPOSED STORM DRAIN EXISTING STORM DRAIN DIRECTION OF FLOW - CATCH BASIN FILTER INSERT SEE HYDROLOGY AND HYDRAULICS REPORT FOR DRAINAGE AREAS 1 1PAL11 IT Ii I -i TABLE OF CONTENTS PAGES ViCINITY MAP . ....................................................................................................* .................................................................................................... INTRODUCTION....' ........................................................- ....- ................................................................................................................2 PROJECTDESCRIPTION.................................................................................................................................... POLLUTANTS AND CONDITIONS OF CONCERN...............................................................,..,..,,5 PERMANENT STORM WATER BEST MANAGEMENT PRACTICES ... .. ... ........ ........ ...................................... 6 OPERATION AND MAINTENANCE PLAN., S SUMMARY........................................ .... .............. ....... • ................................................................................................• ...9 APPENDICES A., STORM WATER. REQUIREMENT APPLICABILITY CHECKLIST TABLES FROM THE CITY OF CARLSBAD STORM WATER STANDARDS MANUAL CALCULATIONS FOR ONS1TE WATER QUALITY TREATMENT FLOW REQUIREMENTS AND WATER QUALITY TREATMENT PRODUCT INFORMATION MAP POCKETS . 1. WATER QUALITY SITE PLAN EXHIBIT FOR LA COSTA RESORT AND SPA MASTER PLAN AMENDMENT May 2003 Revised: Noyeniber3, 2003 INTRODUCTION This Storm Water Management Plait (SWMP) describes the pethianerit Storm Water Bst Management Practice (BMPs) recommended to be implemented fox the La Costa Resort and Spa Master Plan Amendment project, that satisfy the requirements identified in the following Ij S documents: State Water Resources Control Board (SWRCB) Order No. 99-08 DWQ, National Pollutant Discharge Elimination System (NPDBS) General Permit No. CAS000002 for Discharges of Storm Water Runoff Associated With Construction Activity.. San Diego Region Municipal NPDES Storm Water Permit, Order Number 2001-01 (Municipal Permit). City of Carlsbad Standard Urban Storm Water Mitigation Plan (SUSMP), Storm Water- Standards Manual dated April 2003. Included in this report are the p'eliminary storm rtinoffcaiculatibns necessary to size the I proposed BMPs, the BMP sizing calculations, technical infôimation for.the proposed BMPs and a discussion on the operation and maintenance requirements for the permanent BMPs. 1 I I I I. I May t,2003 U 2 - Revised: Novmber3, 2003 serve to discharge storm ninoffbato the 36-inch RCP public storm drain system (crosing under El Camino Real), located northeast of the intersection of'EI Cathino Real and Costa Del Mar Road and the existing storm drain system located at the westerly end of Costa Del Mar' Road., May 1, 2003 4 Revised: November 3,2003 -. I i I I PERMANENT STORM WATER BEST MANAGEMENT PRACTICES The Municipal Permit and the City Storm Water Standards require the implementation of applicable site design, source control, project specific, and treatment control BMPs,. To ñaeet these requirewents, the project will incorporate a series of 'non-structural and structural BMPs to the maximum extent practicable (1v.LEP).. A detailed description of each type of BMP is discussed below: Site Design BMPs The following site design BMPs have been applieth Minimize the inipercrious footprint by increasing building density while decreasing building footprint,. Minimize directly connected impervious areas to the maximum extent practicable.. Avoid draining water over tops of'slopes in order to miiifm'ze erosion.. Source Control BMPs Source control BMPs are generally non-structural and are intended to reduce the quantity of pollutants entering the storm thaiii system..' The following source control BMJPs are proposed to be utilized for the LA Costa Resort and Spa Master-Plan Am'eIldmeutj,Ioject: Trash storage areas to be paved with an impervious surface, designed to prevent offsite transport of trash. Pest resistant plants will be planted to reduce the need for' pesticides, An efficient irrigation system will be installed within the landscaped areas that addresses the specific'waterreqiifrements for those landscaped areas,. Concrete stamping or stenciling of 'inlets and catch basins., Distribution integrated pest management education materials to future site tenants.. 1 I . May , 2003 6 Rvised November 3, 2003 I OPERATION AND MAINTENANCE PLAN I: XSL La Costa Resort Corporation, a Delaware corporation,, will onstruct the improvements proposed for the La Costa Resort and Spa Master Plan Amendment and shall be required to maintain all BMPs on the site. ,• I •0 The site shall be kept in a neat and orderly fashion with a regularly scheduled landscape maintenance crew in charge of keeping gutters and inlets free oflittex and debris.. The landscape crew will also maintain the landscaping to prevent soil erosion and minimize sediment transport; F- Inlet stamps shall be inspected and iapplied as needed, 1.' The project consists of three proposed and three existing type 'S' curb inlets, which will include [ bio-cleau filter inserts,, Bio -Clean Environmental Services recommends replacement of the hydrocarbon absorption boom four times per year. Currently the approximate cost to replace each boom is $80.00.. This amounts to a maintenance cost of approximately $320.00 per year per inlet,. The proposed project will utilize one CDS Technologies Storm Water Treatpient Unit. Currently, the apprpximate maintenance cost for one CDS Technologies Unit is $4,500.00 per year which includes $300 .0Oper haui for labor with a 4-hour minimum and a $300.00 waste disposal fee per, maintenance service for the imit. The maintenance cost assumes that the CDS Technologies Units are serviced three times a year,,. These are preliminary costs.. 1 KSL La Costa Resort Corporation shall retain maintenanàe records of'at least 5-years, which shall be made available to the City of San Diego for inspection upon request..- .May,2003 8 Revised: November-3.203 STORM WATER REQUIREMENTS APPLICABILITY CHECKLIST I., I 1 I Storm Water Standards 4/03/03 1 I I I 1•••• Section 2., Construction Storm Water BMP Requirpménts: If the answer to question I 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.. remMning 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 requirement 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 &zrthg construction? Yes No 1.. Is the project subject to California's statewide General NPDES Permit for Storm Water Discharges Associated With Con stniction-Aôtivities? 2. Does the project propose grading or soil disturbance? . . 3.. Would storm water or urban runoff have the potential to contact any portion of the cons&uction area, Including washing and staging areas? 4. Would the xaject use any construction materials that could negatively affect water quality if discharged from the site (such as, paints, solvents, concrete, and stticco)? 31 j TABLES FROM TILE STORM WATER STANDARDS MANUAL Storm Water Standards 4/03/03 1; _ r When refened to this Section, by Step 2 of Section U, cprnplete the analysis required f J your project in the subsections "of Section 111i below. 1.. IDENTIFY POLLUTANTS & CONDITIONS OF CONCERN. A. Identify Pollutants from the Project Area Using Table 1, identify the project's anticipated pollutants.. Pollutants associated wit any hazardous materiel sites that have been remediafed or are not threatened by th proposed project are not considered a pollutant of concern.. Projects meeting th definition of more than one project category shall identify all general pollutant categori that apply. Table 2. Anticipated and Pbtenthl Pcflutn Generted by Land Use e.. General Pollutant Categories Project Trash Oxygen Bacteria Categoiies féavy Organic & Demanding Oil & & - Sediments Mitrients Metals Compounds Debris Substances Grease Viruses Pesticides 1 Detached ResldenttI X X •. X X X X Development - r *c he Residential X X X PCI) Pp.. PCI) X Development Commercial Development •. PV) •• X P(5) X CIJ p(S) >1oo,qooft S Automotive Repair x . X •. RePaurants - X X )C X Hi1tide • Develapmen X X •. X X X X >5,000 t12 . 1 Parking Lots PC'.)' PCI) X X P(t) X - PtI) Slreets, .• 0 Highways & X pliix X XN) X PCI) X Freeways . - X= anticipated -. Ppotntial (I) A potential pollutant if landscaping exists on-site. A pqteritial pollutant if the project includes uncovered parking areas. A potential pollutant if land use involves food or animal waste products. . Including petroleum hydrocarbons.. I - (5) lncIudirr sOWents. 12 Storm Water Standards 4/03/03 Table 4., Structural Treatment Control BMP Selection Matrix.. Pollutant of Concern Treatment Control BMP Categories 81of111ers . Detention Infiltration Wet Ponds or Drainage F1ltratioi f l-lydrodynamic L Basins Basins(l) WeUandC Inserts J Separator Systerns(21 Sediment •, M' H J H H I H M Nutrients L M M M . I M L - Heavy Metals M M ' - I-I I - I-f ' I Organic Compounds U LI U U L M -j , I Trash &'Debris I. I H . U U M H M Oxygen Demanding I M M M 1- M 1. Substances . Bacteria U Ii H U L_. . M I Oil & Grease lit M U U H L Pesücides U .. U U . U t I U ' L (1) Including trenches and pwous pavement, (2) Also known as hydmdynamic devices arid baflIeboxa. Low removal efficiency Medium removal efficiency H: High removal efficfncy U: Unknown temoval efficiency Sources: Guidance SpecJzj!ng Management Measures for Sources of Nonpoipi PeRu//thin Coastat Waters (1993), IvaiOnaf Ston'nwater Best Manaqethenl Practices Database (2001). and Guide for BMP Selection in Udan DeveloL'edAreas (2001). Y. Restrictions on the Use of infiltration Treatment BMPs 31.. 'Treatment control BMPs that are designed to primarily function as infiltration devices shall meet the following conditions (these conditions do not apply to treatment BMPs which allow incidental infiltration and are not designed to primarily function as infiltration devices, such as grassy swales, detention basins, vegetated buff' strips, constructed wetland4,etc.): (i rnoff(rpm comrnexciaI dihmen'Ishafl inderb pretretment to remove both physical and chemicl contaminants, such as sedimentation or, filtration, prior' to infiltration; (2) all dry-. weather flows shall be diverted from infiltration devices except for those non-storm water discharges authorized pursuant to 40 CFR 122.26(d)2)(w)(B)(1): diverted stream fIovC, rising ground water's, uncontaminated ground water infiltration Las defined at 40 CFR 35.2005(20)] to storm water conveyance systems, uncontaminated pumped ground water, foundatiOn drains, springs, water' from crawl space pumps, footing drains, air conditioning condensation, flow from riparian habitats and wetlands, water line flushing, landscape irrigation, discharges from potable water' sources other than water' .main breaks, irrigation water, individual residential car washing, and dechlorinated swimming pool discharges; (3) pollution pr'vention and source control BMPs shall be implemented at a level appropriate to protect groundwater quality at sites where infiltration structural treatment BMPs are to be used; (4) the vertical distance from the base of any infiltration structural treatment BMP to the seasonal high groundwater mark shall be at least 10 feet.. . Where groundwater- does not support beneficial uses, this, vertical distance criterion ma' be reduced, provided groundwater quality is maintained; (5) the soil through which infiltration is to occur shall have physical and 21 FLOW BASE]) NUMERIC SIZING CALCIJLA110NS The structural treatment BMPs for the La Costa Resort and Spa Master Plan Aineridment piojedt will be sized using flow based criteria per the City's Storm Water Standards Manual, Table 3. This criteria states that the flow based BMPs shall be designed to mitigate (infiltrate, filter- or treat) the maximum flow rate of runoff produced from axainfall intensity of'O.2 inch of 'rainfall per hour.." Structural I3MP sizing calculations are as follows: Bio-Clean Filters Per' the manufacturers specifications (see calculations, this Appendix), one Bio- Clean filter is capable of 'treating arunoffflow Qf 0,35 cfs based on the above described area. Therefore the maximum surface area that can be effectively treated by one Bio-Clean Filter is S acres, per the following calculations: Q--CIA, therefore A=Q/C(l); Q=0..85 cfs, 1=0.2 in/h4 and assuming a commercial runoff coefficient, C, of 085 A-0..85/085 (0.2)=5..0 acres,. f Per the attached site BMPfBasin Area Exhibit (see Map Pocket) the two existing inlets located at node 620 (per the La Costa Resort and Spa Master Plan Drainage Study, dated November 3, 2003) collect runoff flom the largest contributing ai'ea of 8.3 acres (this area is conservative in that it includes some landscaped area which will be picked up by the private underground stomi chain system).. Per the calculation above, the Bio-Clean inserts to be installed in these two existing inlets will be able to treat a combined maximum area of 10 acres and will therefore have sufficient capacity to treat the runoff flour this area. The contributing area to each of the refnaining four' Type B inlets (located at nodes 510,540, 541 and 621 peX the attached Site BMPfBasin Area Exhibit) is less than 5 acxe,, Therefore the Bio- Clean inserts to be installed in these inlets will also have sufficient capacity to treat the surface runoff within each area, CDS Technologies Storm Water Treatment Unit Per the La Costa Resort and Spa Master Plan Diaiiiage Study dated November 3, 2003, the total basin area contributing runoff, to be rated to the proposed CDS Unit (node 544) is approximately tenty-three acres.. The storm runoff requir:ed to be treated by this unit per the Cits Storm Water Standards Manual, is calculated as follows: Q--CM, where C=O..85, 1=0.2 in/hi, A=23 acres Q--(O.. 85) (0.2) (23) = 19 1, or approximately 4 cf The CDS Unit, Model No.. PMSU40 30 is designed for a maximum flow of 4.5 cfs and is proposed to be used for this project.. - 41 PLAN VIEW CDS MODEL PMSU40_.303 4.5 CFS TREATMENT CAP ---*- ELEVATION VIEW 1— SEE-SHEET 2 57tH PIP XX'ø OULE1 PIPE 30'ø MI-I FRAME AND CVER CTYPICAL) ALTERNATIVE ACCESS HATCH SYSTEMS RZiDLY AYAILALE ID CUNC, RISER 1Z\CflNCRETE TOP W RE Jo L — _ ELEVATION VIEW SEE SHEET NOTE: THE INTERNAL COMPONENTS ARE SHOWN IN THE RJGI-ff—HAND CONFJCLJRATION—THESE CDUPOF4ENTS MAY BE FURNISHED IN THE MIRROR IMAGE TO THAT SHOWN (LEFT—HAND CONFIGURATION).. IDATE I SCALE PROJECT/ DEVELOPMENT 1 3/24700 1 •i"=3' NAME IDRAWN I SHEET CITY & STATE JPPROV, -J 1 - SECTION VIEW CDS MQDEL PMSU40_30, 4.5 CFS TREATMENT CAP. A \ 4 LLLLLLL L.LLLLLLLLJ LLL,LLI . .A.. ftL. ...,,. %. .& .•. •. - ROTATE siio SLAB TO OBTAIN INDICATED OFFSET ... ..\.• 'p DISTANCES FLANGES ON INLE14 SID & PO1TOM / A1TCH8) TO :RISER WALL USING S ANCHOR BOLTS. .MINIMUM-(SUFPUED BY 'COS TECHNOLOGIES) q STORM PIPE ftft' \. , .:...";i. •/\ ATrACHSCREDt \' •.: , . , \ To SLAB USING 4 \. :.• .Y '. ANCHOR' SO, supus BY cos. \_ ACCESS RISER. \--.)(X-o INLET PIPE S xX0 our,r PIPE ROb—HAMMER OR SAW CUT OPENING~S FOR PIPE INLET AND Otiii.Er AS NECESSARY OIL. CENTER OF 960 'MH RISER SECTIONS CENTER OF SCREEN, 2a6 SUMP OPENING SEPARATION SCREEN, SEE NOTE NO.. 2 NOTES: . •. , 1. THE INTERNAL COMPONENTS ARE SHOWN IN THE RIGHT—HAND CONFIGURATION—THESE COMPONENTS MAY BE FURNISHED IN THE MIRROR IMAGE TO THAT SHOWN (LEFT—HAND CONFIGURATION). 2.. FOR PROPER INSTALLATION, GREEN FLANGE ON SCREEN FACES UP. 0 . DATE I SCALE PRO JECT/ DEVELOPMENT 3/24/00 1 "=2. D5IT NAME . DRAYN - . ( SHEET CITY & STATE - TECHNOLOGIES 0•0 - . APPROV. .. . '. ... PATENTED.. . 11 A 1BIG ciu STOR M W A M s s -s P0 Bat 869, CEad, CA 92049 ii . .. .• Fax (760) 433-33176 TxgffesIuw -• . . •. . ! : an Diego regional standard Curb 1n1et Type 11 Manhole 4 j Catches old . verythir / )MSt ..'Floatabies. frornboth / TDE •.. ph ow ..Islde§ and /.*n. 1 1W LU1 catcher- ftnt 4)11 JJ I 1/ emovab1 basket ___ • 1 catches. 1 U J verything ate J 12 . Remove through. [Curb!man . i .. without S.,. entry aske I • • •. • . • • • • .5.. . , 1 . - - .. - -. . • I I . . • . I I I H W'i FI,JT j ... 11. I R-'Jvcb TWT FL)W cJAn-j ALtu.AT'thJ FO .. f1O CLj2J3 frJ(&Y AS7 TW A1-J jP5 fl CALWLy/J PL) 1 0120 PFOMP r6V lN1tCOMPMJ. I BASED O&) jet-) j of2jv\Ayp..j P oTj oF EiiZ o CAJ CLcJ 71 V49-1 P- I I I I I •I I (s 1 I .1 kr f1 ; 3~" c*vE Fi-oJ iY)tj :. Ti PcL : -f 9.55"" S I.4 I . [c~ C.LGJ AJ c -- •1 T \t¼1R iFj1Ep S. f ---S - BAlDBOQEC OF %TtRAULICS 1 WEIRS 54 Table 5-3. Values of C in the Fotmulo. Q CLY05 for Broad- Tablo 5-5. Values of C In the Form crested Weirs created Weirswith Oreat me ed8ligh ji etal, of arest of wtr In iop • 3.00 40\\_ Rne ry d - t, 0.0.78t.00.802.00\.60 Creak 2.042.612A SAS 422-70 2-70 2-7 \U 1 9.32 3.2g a..28 3.a7 2.80 2 782 68 2 662 65 2 . 6 4 2 6 18 662.65 * 20 332a218R03032852 7 5 2 7 2 2 8 8 2 8 5 26426 SIODI 01 !jengb Bead In Zi 2.6 ,328.3Z3.213,293.07'4.$92. 8 1 2 . 1 2 2 . 0 7 2 . 5 4 2 . 8 2 OtIt of wair !It last IDA fl.2 0.3 0.4.. 0.5 06 2,0 3,823.28.323.82E208.05 2 . 0 2 2 . 2 . 0 0 2 . 6 4 07 2.5 8.23B23.323,B23,39.I92.9T 2 . 7 8 2 ,68 2,64 2.65 . 19 to 4,0 32:323.222.523.323.323.O 7 2 . 7 0 2 . ' ' 0 2.64 2.68 LD 2 2.87 2.57 i180i ...... 2.801 2.84 2.70 4.8 8,823 3.82 3.22 8.82 8132 3.22 2.98 2.7 2.84 2.6 80 .11ota 2.001 2.60 2.74 2.62 5.0 3.223;325.323323.828.323.322.0 7 2 9 2 . 5 . 4 . 2.Ô 1. t . . .68 2.73 2.80 2.00 2.80 2.63 3.6 3.323.823.323.323,323.82 3 . 3 2 3 , 3 2 2 . 8 8 2.54.26 • • Table 5-4. Vaiuee of C it the Pcrma Q CIH3.for Models Cm the Form u la Q CL3S 0t W of T Trianguitir - Cross 6C10fl 'y1 Verlea1 tTpetream Pace • of Broo.c1..oreotd Weirs with oundd sreaIn Comer - g Downstream y", • I: and Movingai 0 experim 310 4.0 5.0 In (601 - • -1 --,,• - -- •.-.-:. c--•ç. •.• -- -. - - - - - - - - - - - - - - - - •• • + + 1. .' + / S / I • ( . i r • • • • + + • ,: • • • ••• •• . • •;•. • •• r 1 •\• ••••'\ • • ••• 3C • 28 •• • S j • \ \ IMM Ni Alt + J 55 • •:•••• - 555 7)15 / Ail AA 7F Tr ¼ 7 A4 \ P' .- 1 \ ' - Cr1 •. ç'\ c. • • S S - •t \• ¼.) •, ...\ \ -\4. - •• 4'--- ' S SITE BMP/ BASIN AREA EXHIBIT • ••: • S S.. • S • S 5 • •• • DLOPED CONION S • S S • S S S S 5 • 5 5 •5 • S OU/ • S • 5 5 4 S • S • 5 • 55 • • • Cc SA2Th/A$4 • S S S -S InC1=21t iCSTING 5TOIrm D44A3? MAP= SCALE W --* J ____ ____-- — -