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HomeMy WebLinkAboutCT 04-15; LA COSTA GREENS NEIGHBORHOOD 1.7; STORM WATER MANAGEMENT PLAN; 2005-04-20STORM WATER MANAGEMENT PLAN for LA COSTA GREENS NEIGHBORHOOD 1.7 CT 04-15 City of Carlsbad, California Prepared for: Real Estate Collateral Management Company c/o Morrow Development 1903 Wright Place. Suite 180 Carlsbad, CA 92008 W.O. 2352-107 April 20, 2005 Eric Mosolgo, R.CE. Water Resources Department Manager Hunsaker & Associates San Diego, Inc. DE:de H:\REPORTS\2352\107 N 1.onSWMP05.doc W.O. 2352-107 4/20/2005 6:29 PM V- z < La Costa Greens Neighborhood 1.7 Storm Water Management Plan TABLE OF CONTENTS CHAPTER 1 - Executive Summary 1.1 Introduction 1.2 Summary of Pre-Developed Conditions 1.3 Summary of Proposed Development 1.4 Results and Recommendations 1.5 Conclusion CHAPTER 2 - Storm Water Criteria 2.1 Regional Water Quality Control Board Criteria 2.2 City of Carlsbad SUSMP Criteria CHAPTER 3 - Identification of Typical Pollutants 3.1 Anticipated Pollutants from Project Site 3.2 Sediment 3.3 Nutrients 3.4 Trash & Debris 3.5 Oxygen-Demanding Substances 3.6 Oil & Grease 3.7 Metals 3.8 Bacteria & Viruses 3.9 Pesticides CHAPTER 4 - Conditions of Concern 4.1 Receiving Watershed Descriptions 4.2 Pollutants of Concern in Receiving Watersheds CHAPTER 5 - Flow-Based BMPs 5.1 Design Criteria 5.2 CDS Treatment Units 5.3 Pollutant Removal Efficiency Table 5.4 Maintenance Requirements 5.5 Operations and Maintenance Plan 5.6 Schedule of Maintenance Activities 5.7 Annual Operations & Maintenance Costs DE: H:\REPORTS\2352\107N 1.07«WMP05.doc W.O. 2352-107 4/20/2005 6:29 PM La Costa Greens Neighborhood 1.7 Storm Water Management Plan CHAPTER 6 - Source Control BMPs 6.1 Landscaping 6.2 Urban Housekeeping 6.3 Automobile Use 6.4 Site Design BMPs CHAPTER 7 - Treatment Control BMP Design (CDS Treatment Units) 7.1 BMP Locations 7.2 Determination of Treatment Flows 7.3 CDS Treatment Unit Selections CHAPTER 8 - Fiscal Resources 8.1 Fiscal Mechanism Selection 8.2 Agreements (Mechanisms to Assure Maintenance) CHAPTER 9 - References List of Tables and Figures Chapter 1 - Watershed Map Chapter 3 - Pollutant Category Table Chapter 4 - San Diego Region Hydrologic Divisions Chapter 4 - Combined 1998 and Draft 2002 Section 303(d) Update Chapter 4 - Beneficial Uses of Inland Surface Waters Chapter 4 - Water Quality Objectives Chapter 6 - Pollutant Removal Efficiency Table (Flow-Based BMPs) Chapter 7 - 85*^ Percentile Rainfall Isopluvial Map Chapter 7 - Neighborhood 1.7 BMP Location Map Chapter 7 - Design Runoff Determination Summary Table Chapter 7 - CDS Unit Treatment Capacity Table Chapter 7 - CDS System Data Chapter 8 - Maintenance Mechanism Selection Table Attachments BMP Location Map DE:de H:\REPORTS\2352\107 N 1.07\SWMP05.doc W.O. 2352-107 4/20/2005 6:29 PM La Costa Greens Neighborhood 1.7 Storm Water Management Plan CHAPTER 1 - EXECUTIVE SUMMARY 1.1 - Introduction The La Costa Greens Neighborhood 1.7 site is located north of Poinsettia Lane and west of Alicante Road in the City of Carlsbad, California (see Vicinity Map on this page). The 41-acre site is bounded to the east and north by the existing Bressi Ranch residential development, and to the west by the proposed La Costa Greens Neighborhood 1.6 residential development. PROJECT SITE LA COSTA VjClNITYMAP H7S All runoff from the site will drain south to the Alicante detention basin, south of Poinsettia Lane, ultimately draining to an unnamed tributary of San Marcos Creek. Runoff from this tributary eventually discharges into San Marcos Creek towards the Batiquitos Lagoon. Per the City of Carlsbad SUSMP, the La Costa Greens Neighborhoods 1.7 project is classified as a Priority Project and subject to the City's Permanent Storm Water BMP Requirements. DE:ds H:\REPORTSV2352\107 N 1.07\SWMP05.doc W.O. 2352-107 4/20/2005 6:29 PM La Costa Greens Neighborhood 1.7 Storm Water Management Plan This Storm Water Management Plan (SWMP) has been prepared pursuant to requirements set forth in the City of Carlsbad's "Standard Urban Storm Water Mitigation Plan (SUSMP)." All calculations are consistent with criteria set forth by the Regional Water Quality Control Board's Order No. 2001-01, and the City of Carlsbad SUSMP. This SWMP recommends the location and sizing of site Best Management Practices (BMPs) which include two CDS treatment units (or approved equivalent flow based treatment units). See BMP Location Map in this chapter. Furthermore, this report determines anticipated project pollutants, pollutants of concern in the receiving watershed, peak flow mitigation, recommended source control BMPs, and methodology used forthe design of flow-based and volume- based BMPs. 1.2 - Summary of Pre-Developed Conditions The site is located north of Poinsettia Lane, east of Alicante Road, and east of the proposed La Costa Greens Neighborhood 1.06 (see Vicinity Map). Located in the Batiquitos watershed, the site consists of primarily hilly, undisturbed terrain covered with natural vegetation. The site receives offsite runoff from the adjacent Bressi Ranch residential development to the north. Peak flow data from the adjacent Bressi Ranch development, was obtained from the referenced PDC plans, attributing 25.1 cfs to the proposed site in ultimate developed conditions. Natural runoff from the undeveloped site flows in a southerly direction towards Poinsettia Road, where it is intercepted by four headwalls, then conveyed beneath Poinsettia Road to the Alicante detention basin. Flow from this basin then flows southwards to an unnamed tributary of San Marcos Creek, which then, flows in a southerly direction along the site boundary of the La Costa Greens Golf Course, west of the Phase I development area. All the runoff eventually drains under Alga Road via three 96" RCP culverts, as shown in Drawing No. 397-2, and discharges into San Marcos Creek towards the Batiquitos Lagoon. The Regional Water Quality Control Board has identified San Marcos Creek as part of the Carlsbad Hydrologic Unit, San Marcos Hydrologic Area, and the Batiquitos Hydrologic Subarea (basin number 904.51). DE:ae H:«EPORTS\2352\107 N 1.07\SWMP05.doc W.O. 2352-107 4/2Q/20O5 6:29 PM OCEANSIDE CARLSBAD ENQNITAS WATERSHED MAP FOR LA COSTA GREENS 1.7 Cmr OF SAN DIEGO, CAUFORNIA t^lUMJMM IlllllillllJ La Costa Greens Neighborhood 1.7 Storm Water Management Plan 1.3 - Summary of Proposed Development Development of the 41-acre area will consist of 71 single-family residences, a proposed school site, associated roads, foot paths, communal open space, onsite parking and underground utilities with two (2) entrances from the adjacent Poinsettia Lane. Runoff from the proposed 41-acre developed area will drain to four points of discharge. The northern body of development bordering Street "A", the western segment of the proposed La Costa Greens Neighborhood 1.06 and the existing Bressi Ranch residential development flow will drain south westerly along the current natural flowpath, where it will discharge to the existing 48" RCP headwall (Headwall 1), draining to the Alicante detention basin. Flows for the existing site were attained from the "Grading and Drainage Plans for Poinsettia Lane", Dwg.# 397-2H, dated January 24, 2003 by Kimley-Horn & Associates. The central body of the development, inclusive of the school site and offsite drainage will drain south along Street "B", where it will exit to the existing 48" RCP headwall at Poinsettia Lane (Headwall 2). Runoff will then enter the existing Alicante detention basin. Runoff from graded terrain west and south of the site bordering La Costa Neighborhood 1.6 and Poinsettia Lane will drain south to existing 36" RCP & 24" RCP headwalls (headwalls 3 and 4) before entering the Alicante detention basin. 85*^ percentile runoff will be treated in storm water BMPs priorto discharge to the existing storm drain and detention basin. Based on County of San Diego criteria, runoff coefficients of 0.55 and 0.85 were assumed for the proposed single-family residential development and school site respectively. Flow-based BMPs will be located at the site discharge locations. 85"^ percentile runoff will be treated in proposed CDS units upstream of the tie in to the existing Poinsetta Lane storm drain system priorto discharging to the Alicante detention basin. DE:da H:\REPORTS\2352M07N 1.07\SWMP05.doc W.O. 2352-107 4/20/2005 6:29 PM La Costa Greens Neighborhood 1.7 Storm Water Management Plan 1.4 - Results and Recommendations Table 1 below summarizes rational method 85'^ percentile calculations for the proposed water quality treatment units for the La Costa Greens Neighborhood 1.7 development. Table 1 - Developed Conditions 85*^ Percentile Calculations Area Drainage Area (acres) Rainfall Intensity (inclies/hour) Runoff Coefficient 85*" Pet. Design Flow (cfs) West Storm Drain Unit 26.4 0.2 0.67** 3.5 East Storm Drain Unit 42.3* 0.2 0.56** 4.7 •Note: Includes area from Bressi and 1.06 developments **Note: Weighted C Coefficients - See Chapter 7 Rational Method calculations predicted an 85*^ percentile mnoff flow of roughly 3.5 cfs for the area discharging to the western storm drain unit and 4.7 cfs for the area discharging to the eastern storm drain unit. 85*^^ percentile flows will be treated in one of two proposed CDS units prior to discharging to the Alicante detention basin. A single CDS Model PMSU 40_40_10 & CDS Model PMSU 40_30_10 treatment unit (or approved equivalent units) with respective treatment flow capacities of 6 cfs and 4.5 cfs are recommended forthe units located upstream of the Alicante detention basin. 1.5 - Conclusion The combination of proposed construction and permanent BMP's will reduce, to the maximum extent practicable, the expected project pollutants and will not adversely impact the beneficial uses of the receiving waters. De:de H:\REPORTS\2352\107N1.07\SWMP0S.doc W.O. 2352-107 4/20/2005 6:29 PM PROPOSEO sTom'mwi TREATUENT UNIT (TO BE HOA * LEGEND WATERSHED BOUNDARY FLOWLINE WATER TREATMENT UNIT LEGEND WATERSHED BOUNDARY FLOWLINE WATER TREATMENT UNIT / / ^ L pRgpnsEB Cl£iiNWTS- TtE.PI>Ol'()SEiySTORU'DRMN'm lO. _ "io EXI'^VNG PIPE AHO SWB PEP DRAHIHC NO. 337-12 (PQSTmC H^WALL Ta BC imiOVBl) LpROproSED STORU WATER'TREATUEm um (TO •BE.MOA.MAINTAINEIf).,^,.- - . .• ' . - _ PREPARED BY: HUNSAKER & ASSOCIATES SUKVEYTNC mOSBjSSmoO-F)(laS«B5»VH BMP LOCATION MAP FOR LA COSTA GREENS NEIGHBORHOOD 1.07 cir/ OF CARLSBAD. CALIFORNIA SHEET 1 OF 1 Ri\O:506\a,Hyd\O386»HO3-BMP,dwQC E085]Apr-20-2005il8O7 La Costa Greens Neighborhood 1.7 Storm Water Management Plan CHAPTER 2 - STORM WATER CRITERIA 2.1 - Regional Water Qualitv Control Board Criteria All runoff conveyed in the proposed storm drain systems will be treated in compliance with Regional Water Quality Control Board regulations and NPDES criteria priorto discharging to natural watercourses. California Regional Water Quality Control Board Order No. 2001-01, dated February 21, 2001, sets waste discharge requirements for discharges of urban runoff from municipal storm separate drainage systems draining the watersheds of San Diego County. Per the RWQCB Order, post-development runoff from a site shall not contain pollutant loads which cause or contribute to an exceedance of receiving water quality objectives or which have not been reduced to the maximum extent practicable. Post-construction Best Management Practices (BMPs), which refer to specific storm water management techniques that are applied to manage construction and post-construction site runoff and minimize erosion, include source control - aimed at reducing the amount of sediment and other pollutants - and treatment controls that keep soil and other pollutants onsite once they have been loosened by storm water erosion. Post construction pollutants are a result of the urban development of the property and the effects of automobile use. Runoff from paved surfaces can contain both sediment (in the form of silt and sand) as well as a variety of pollutants transported by the sediment. Landscape activities by homeowners are an additional source of sediment. All structural BMPs shall be located to infiltrate, filter, or treat the required runoff volume or flow (based on the 85*^ percentile rainfall) priorto its discharge to any receiving watercourse supporting beneficial uses. 2.2 - Citv of Carlsbad SUSMP Criteria Per the City of Carlsbad SUSMP, the La Costa Greens Neighborhood 1.7 project is classified as a Priority Project and subject to the City's Permanent Storm Water BMP Requirements. These requirements required the preparation of this Storm Water Management Plan. The Storm Water Applicability Checklist, which must be included along with Grading Plan applications, is included on the following page. DE:de H:\REPORTS\2352V107N1.07\SWMP05.doc W.O. 2352-107 4/20/2005 6:29 PM storm Water Standards 4703/03 APPENDIX A I I I I •4 I STORM WATER REQUIREMENTS APPLICASILITY CHEGKLIST Complete Sections i and 2 of the follawina charWkt »n MI*™- permanent and construction storm wSrbest mana—n^^ your project's This fcmn must be completed and suhmtted ^u^pSappScT Section 1. Permanent Storm Watar BMP Rsquiremenis- • rr any answers to Part A are answered "Yes," vour Droiert cnhian+ +k • «n rrr:at'e"rreTuirtm\"n^t3^ — -"perS 1^ IT —; • J . . . -'•wm4--in, VJI.UUH yvelisr DiVli cayegories?^''^ ""^^^ definition of ona or mora of tha priority projert Detached residential development of 10 nr.mnra nnit^ AHn^ho^ ,..»;j__.u_j —;—r-r: -. -2. Attached residential development of 10 or mora units 3. Commercial development greater than 100,QOQ square faat 4. Automotive repair shop 5. Restaurant ~— 6. Steep hiiiside development greater than 5,000 square feet ^ 7. Project discharpinp to receiving waters within EnvirQnmentallv Ser^^^itiv^ Am.; • nn?JnH^ r^^^' ^T. °' f'^^' ^° ^-"Q" ^ °^ '^^^^ ^ ^ P^ri<iag spaces, and potentially exposed to urban runoff H-^^^, <:tf iu 2- ^^'^?nnn f ^' ^'f and freeways which would create a new paved surface that is a.QQQ squara feet or greater .lauc mauc Yes 7 No 1/ ^^a^^SS^'^''^ ' 'VVa/ar S^^dard^for expanded definitions of the prioril L/Vn/fed Bxclusior}-. Trenching and resurfacing worit associated with utilltv Drolects are not cnnsiripr?d pnonty projects, ParKing lots, buildings and other structures associateKS proS^^^^^ conSn'u^'2 Part B°"' °'^ ^" answe'to PS ATe^No" La Costa Greens Neighborhood 1.7 Storm Water Management Plan CHAPTER 3 - IDENTIFICATION OF TYPICAL POLLUTANTS 3.1 - Anticipated Pollutants from Proiect Site The following table details typical anticipated and potential pollutants generated by various land use types. The La Costa Greens Neighborhoods 1.7 development will consist of detached single-family residences and a school site. Thus, the Detached Residential Development & Parking Lots categories have been highlighted to clearly illustrate which general pollutant categories are anticipated from the project area. General Pollutant Categories Priority Project Categories Sediments Nutrients Heavy IVietals Organic Compounds Trash & Debris Oxygen Demanding Substances Oil & Grease Bacteria & Viruses Pesticides Detached Residential X X X X X X X Development Attached Residential Development X X X p(i) p(2) P X Commercial Development > 100,000 ft^ p(1) p(1) p(2) X p(5) X p(3) p{5) Automotive Repair Shops X X X Restaurants X X X X Hillside Development >5,000 ft^ X X X X X X Parking Lots p(1) p(1) X X p(1) X p(1) Streets, Highways & Freeways X p(1) X X(4) X p(5) X Retail Gas Outlets X X(4) X X X = anticipated P = potential (1) A potential pollutant if landscaping exists on-site. (2) A potential pollutant if the project includes uncovered parking areas. (3) A potential pollutant if land use involves food or animal waste products. (4) Including petroleum hydrocarbons. (5) Including solvents. DE:de H:\REPORTS\2352M07 N 1.07\SWMP05.doc W.O. 2352-107 4/20/2005 6:29 PM La Costa Greens Neighborhood 1.7 Storm Water Management Plan 3.2 - Sediment Soils or other surface materials eroded and then transported or deposited by the action of wind, water, ice, or gravity. Sediments can increase turbidity, clog fish gills, reduce spawning habitat, smother bottom dwelling organisms, and suppress aquatic vegetative growth. 3.3 - Nutrients Inorganic substances, such as nitrogen and phosphorous, that commonly exist in the form of mineral salts that are either dissolved or suspended in water. Primary sources of nutrients in urban runoff are fertilizers and eroded soils. Excessive discharge of nutrients to water bodies and streams can cause excessive aquatic algae and plant growth. Such excessive production, referred to as cultural eutrophication, may lead to excessive decay of organic matter in the water body, loss of oxygen in the water, release of toxins in sediment, and the eventual death of aquatic organisms. 3.4 - Trash & Debris Examples include paper, plastic, leaves, grass cuttings, and food waste, which may have a significant impact on the recreational value of a water body and aquatic habitat. Excess organic matter can create a high biochemical oxygen demand in a stream and thereby lower its water quality. In areas where stagnant water is present, the presence of excess organic matter can promote septic conditions resulting in the growth of undesirable organisms and the release of odorous and hazardous compounds such as hydrogen sulfide. 3.5 - Oxvgen-Demandinq Substances Biodegradable organic material as well as chemicals that react with dissolved oxygen in water to form other compounds. Compounds such as ammonia and hydrogen sulfide are examples of oxygen-demanding compounds. The oxygen demand of a substance can lead to depletion of dissolved oxygen in a water body and possibly the development of septic conditions. 3.6 - Oil & Grease Characterized as high high-molecular weight organic compounds. Primary sources of oil and grease are petroleum hydrocarbon products, motor products from leaking vehicles, oils, waxes, and high-molecular weight fatty acids. Elevated oil and grease content can decrease the aesthetic value of the water body, as well as the water quality. DE:de H:\REPORTS\2352\107 N 1.07\SWMP05.doc W.O. 2352-107 4/20/2005 6:29 PM La Costa Greens Neighborhood 1.7 Storm Water Management Plan 3.7 - Metals Metals are raw material components in non-metal products such as fuels, adhesives, paints and other coatings. Primary sources of metal pollution in storm water are 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 cooler tower systems. At low 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 environment, have already led to restricted metal usage in certain applications. 3.8 - Bacteria & Viruses Bacteria and viruses are ubiquitous micro-organisms that thrive under certain environmental conditions. Their proliferation is typically caused by the transport of 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 and aquatic life. Also, the decomposition of excess organic waste causes increased growth of undesirable organisms in the water. 3.9 - Pesticides Pesticides (including herbicides) are chemical compounds commonly used to control nuisance growth or prevalence of organisms. Excessive application of a pesticide may result in runoff containing toxic levels of its active component. DE:de H:\REPORTS\2352M07 N 1.07\SWMPO5.doc W.O. 2352-107 4/20/2005 6:29 PM La Costa Greens Neighborhood 1.7 Storm Water Management Plan CHAPTER 4 - CONDITIONS OF CONCERN 4.1 - Receiving Watershed Descriptions As shown in the watershed map on the following page, the pre-developed La Costa Greens Neighborhoods 1.07 site drains to an unnamed tributary of San Marcos Creek which eventually discharges to the Batiquitos Lagoon within the San Marcos Creek watershed. Development of the site will not cause any diversion to or from the existing watershed to the storm drain system. The Regional Water Quality Control Board has identified San Marcos Creek as part of the Carlsbad Hydrologic Unit, San Marcos Creek Watershed, and the Batiquitos Hydrologic Subarea (basin number 904.51). 4.2 - Pollutants of Concern in Receiving Watersheds San Marcos Creek and Batiquitos Lagoon are not listed on the EPA's 303(d) List of endangered watenways (included in this Chapter). Per the "Water Quality Plan for the San Diego Basin", the beneficial uses for the Batiquitos Lagoon and San Marcos Creek includes agricultural supply, contact water recreation, non-contact recreation, warm freshwater habitat, and wildlife habitat. Table 3-2 from the "Water Quality Plan forthe San Diego Basin" (included at the end of this Chapter) lists water quality objectives for a variety of potential pollutants required to sustain the beneficial uses of the San Marcos hydrologic area. DE:de H:WEPORTS\2352\107N 1.07\SWMP05.doc W.O. 2352-107 4/20/2005 6:29 PM OCEANSIDE ENONITAS WATERSHED MAP FOR LA COSTA GREENS 1.7 Cn^ OF SAN DIEGO, CALIFOHNIA Agua Hedionda Lagoon 2S Los Monos HSA (904.31) 27 Los Monos HSA (904.31) Agua Hedionda Creek Bacterial Indicators^ 6.8 acres 1998 Sedimentation / Siltation lower portion at Moonlight State Beach at San Elija Lagoon Total Dissolved Solids Bacterial Indicators^ Bacteriaf Indicators^ Bacterial' Indicators^ Eutrophic lower 7 miles 2002 150 acres 32 Del Dios HSA at San Dieguito Lagoon Mouth Green Valley Creek Sedimentation / Siltation 150 acres Bacterial Indicators^ Sulfate .0.86 miles 1 mile Color Nitrogen Entire Resen/oir Phosphorus (1104 acres) 34 Felicita HSA (905.23) 35 Felicita HSA (905.23) Total Dissolved Solids Felicita Creek Kit Carson Creek should in 905.21 HSA Total Dissolved lower 0.92 Solids miles Total Dissolved 23 Miramar Reservoir Los HA (906.10) Penasquitos Entire Lagoon ' Sedimentation/ 3^7: Lagoon ' Siltation ^^''^s ^i2£I£!inf Mar (Anderson Canyon^ p^^T r^ ' "-^ ShoreTBeichltErpii;^~- Pacific Ocean Grande B;,rt»ri., Shoreline r = Bactenal Scripps HA (906.30) La Jolla Shores Beach at Caminito Indicators^ La Jolla Shores Beach at Vallecitos La Jolla Shores Beach at Ave de la Playa last updated 9/23/2Q03 ~ " ' ' 0.4 miles 3.9 miles 1998 2002 2002 2002 1998 2002 1998 Daqe 3. of a_ Table 2-2. BENEFICIAL USES OF INLAND SURFACE WATERS • Existing Beneficial Use O Potenllal Bensflcial Use + Excepted From MUN (See Text) Walerbodies are listed mullipla limes if Ihey cross hydrologic area or sub area boundaries. • Beneficial use designalions apply to all tributaries lo the indicaled waterbody. if ncl listed separately. Tabis 2-2 BENEFICIAL USES 2-27 March 12. 1887 Table 2-3. BENEFICIAL USES OF COASTAL WATERS BENEFICIAL USE Coastal Waters Hydrologic 1 N N R R C B £• w H M A M S W S Coastal Waters Unit Basin 1 N A E E .0 1 S 1 A A Q I P A H Mil m War* D V C C M 0 T L P R U Q W R E iNumucr 1 2 M L D E A R N M L L Pacific Ocean ® @ @ ® & ® ® & © @ Dana Point Harbor @ ® ® ® Del Mar Boat Basin @ ® ® ® @ @ Mission Bay ® ® ® ® ® ® ® ® ® ® Oceanside Harbor ® ® ® ® San Diego Bay ^ ® @ ® @ ® ® ® ® ® ® ® Coastal Lagoons Tijuana River Estuary 11.i'l @ ® ® o ® ® @ @ Mouth of San Diego River 7.11 ® @ ® ® ® ® ® @ Los Penasquitos Lagoon 2 6,10 @ © 1$ ® ® ® San Dieguito Lagoon 5.11 @ © © Batiquitos.Lagoon 4.51 €» ® ® & ® San Elijo Lagoon . 5.61 m ® @ ® ® ® ® Aqua' Hedionda Lagoon 4.31. ® m ® ® @ ® & ® Includes the tidal prisms of the Otay and Sweetwater Rivers. 2 Fishing from shore or boat permitted, but other watar contact recrestlonal (REC-11 uses are prohibited. @ Existing Beneficial Use Tabla 2-3 BENEFICIAL USES 2-47 March 12, 1997 Table 3-3« WATER QUALITY OBJECTIVES Concentrations not to be exceeded more than 10% of the time during any one year period. Ground Water Hydrologic Basin Unit Number Constituent (mg/L or as noted) TDS CI SO4 %Na NO3 Fe Mn MBAS ODOR Turb NTU Color Units Buena Vista Creek HA 4.20 El Salto HSA a 4.21 3500 BOO 500 60 45 0.3 0-OB 0.5 2.0 none 15 1.0 Vista HSA a 4.22 1000 b 400 b 500 h 60 10 b 0.3 b 0.05 b 0.5 0.75 b none 15 1.0 Agua Hedionda HA a 4.30 1200 500 500 60 10 0.3 0.05 0.5 0.75 none 16 1.0 Los Monos HSA aj 4.31 3500 800 500 60 45 0.3 0.05 0.6 2.0 15 1.0 Encinas HA 4.40 3500 b BOO b 500 b 60 45 b 0.3 b 0.05 b 0.5 2.0 b none 15 1.0 San Marcos HA ae 4.50 1000 400 500 60 10 0.3 0.06 0.5 0.76 15 1.0 Batiquitos HSA ask 4.51 3500 800 500 60 45 0.3 O.DB 0.5 2.0 15 1.0 Escondido Creak HA a 4.60 750 300 300 60 10 0.3 0.05 0.5 0.75 15 1.0 San Eli/D HSA 4.61 2800 700 600 60 46 0.3 0,05 O.B 1.0 none 15 1.0 Escondido HSA 4.62 1000 300 400 60 10 0.3 0.05. 0.5 0.75 15 1.0 SAN DIEGUITO HYDHQLOGIC UNIT 905.00 Solana Beach HA 5,10 1500 b 500 b 500 b 60 45 b 0.85 b 0.15 b 0.5 0,76 b none 18 1.0 Hodges HA 5.20 1000 b 400 b 500 b 60 10 b 0.3 b 0.05 b 0.5 0.75 b none 15 1.0- San Pasqual HA B.30 1000 b 400 b 500 b 60 10 b 0.3 b 0.05 b 0.5 0.75 b none 16 1.0 Santa Maria Valley HA B.40 1000 400 500 60 10 0.3 0.06 0.5 0.76 none 15 1.0 Santa Ysabel HA 5.50 500 250 250 60 0.3 PENASQUITOS HYDROLOGIC UNIT 0.05 0,5 0.75 none 15 1.0 floe.oo Miramar Reservoir HA af Poway HA 6.10 6.20 1200 750 q 600 300 500 300 60 60 10 10 0.3 0.3 O.OB 0.05 0.5 0.5 0.75 0.75 none 15 15 1.0 1.0 Scripps HA 8.30 Miramar HA 6.40 750 300 300 60 10 0.3 0.05 O.B 0.75 none 15 1.0 Tecolote HA 6.50 HA - Hydroiogio Araa HSA - Hydrologic Sub Area (t-owar casa letters Indlcata endnotes following the table.) Table 3r3 WATEH QUALITY OBJECTIVES Paga 3-29 October 13, 1394 La Costa Greens Neighborhood 1.7 Storm Water Management Plan Chapter 5 - FLOW-BASED BMPs 5.1 - Design Criteria Flow-based BMPs shall be designed to mitigate the maximum flowrate of runoff produced from a rainfall intensity of 0.2 inch per hour. Such BMP's utilize either mechanical devices (such as vaults that produce vortex effects) or non-mechanical devices (based on weir hydraulics and specially designed filters) to promote settling and removal of pollutants from the runoff. Per the request of the City of Carlsbad, 85**^ percentile flow calculations were performed using the Rational Method. The basic Rational Method runoff procedure is as follows: Design flow (Q) = C * I * A Runoff Coefficient C - In accordance with the County of San Diego standards, the weighted runoff coefficient for all the areas draining to the treatment unit was determined using the areas analyzed in the final engineering hydrology report. The runoff coefficient is based on the following characteristics of the watershed: Land Use - Single Family Residential in Developed Areas - Soil Type - Hydrologic soil group D was assumed for all areas. Group D soils have very slow infiltration rates when thoroughly wetted. Consisting chiefly of clay soils with a high swelling potential, soils with a high permanent water table, soils with clay pan or clay layer at or near the surface, and shallow soils over nearly impervious materials. Group D soils have a very slow rate of water transmission. Rainfall Intensity (I) - Regional Water Quality Control Board regulations and NPDES criteria have established that flow-based BMPs shall be designed to mitigate a rainfall intensity of 0.2 inch per hour. Watershed Area (A) - Corresponds to total area draining to treatment unit. 5.2 - CDS Treatment Units The Continuous Deflective Separation (CDS) storm water pollution control devices are designed for the sustainable removal and retention of suspended solids and floatables from storm water. CDS technology utilizes a non-blocking, non-screening process to remove pollutants from storm water flow. Otde H:\REPORTS\2352\107 N 1.07\SWMP05.doc W.O. 2352-107 4/2(V2005 6:29 PM La Costa Greens Neighborhood 1.7 Storm Water Management Plan According to CDS information, the units captures fine sands and solids and are capable of removing more than 80 percent of annual total suspended solids from storm water. Additionally, CDS units are reported to remove 100 percent of floatables as well the following: 100% of all particles in the storm water equal to or greater than one-half the size of the screen opening 93% of all particles equal to or greater than one-third the size of the screen opening 53% of all particles equal to or greater than one-fifth the size of the screen opening Standard CDS units have no moving parts (they are gravity-driven by the hydraulic energy in the storm water flow)), require no power or supporting infrastmcture, and according to CDS infomiation will not clog. Screen and supporting hardware are made of stainless steel and designed to resist corrosion. The units are installed below ground. CDS units have large sump capacities relative to their design flows and only need to be cleaned out with a standard vactor truck one to four times per year. This operation eliminates workers' exposure to materials captured in the units. All 85*'^ percentile runoff from the La Costa Greens 1.07 development will be treated via two (2) CDS units. 5.3 - Pollutant Removal Efficiency Table The table on the following page shows the generalized pollutant removal efficiencies for hydrodynamic separators. Per CDS literature, their units are capable of removing more than 80 percent of annual total suspended solids from stonn water. 5.4 - Maintenance Requirements Flow-based storm water treatment devices should be inspected periodically to assure their condition to treat anticipated runoff. Maintenance of the proposed CDS units will include monthly inspection during the months of October through May (the rainy season) and a single, annual maintenance clean out in March or as directed per monthly inspections during the rainy season (see section 5.6 - Schedule of Maintenance). Maintenance of the CDS units involves the use of a "vactor truck", which clears the grit chamber of the treatment unit by vacuuming all the grit, oil and grease, and water from the sump. Typically a 3-man crew is required to perform the maintenance of the treatment unit. DE:ae H:\REPORTSa352M0rN1.07\SWMP05.doc W.O. 2352-107 4/20a005 3:29 PM Chapter 4; Guidance for Selection of Permanent BMPs Table 4.3 Treatment Control BMP Selection Matriy'^^ Pollutant of • Concern Treatment Control BMP Categori es Sediment Nutrients M Detention Basins H Infiltration Basins'^' H Wet Ponds or Wetlands H Drainage Inserts Filtration Hydrodynamic Separator Systems'^' M Heavy IVietals M M M Organic Compounds Trash & Debris U L U H U U M H L M M H L IV! L Low removal efficiency): M: Medium removal efficiency): H: High removal efficiency): U: Unknown removal efficiency rnq'^T w^r'^'^^o! ^P^'^'^'"^ Management Measures for Sources of Nonpoint Pollution in Coastal Waters (1993), National Stormwater Best Management Practices Database (2001), Guide for BMP Se^Son in Urban Developed Areas (2001). and Caltrans New Technology Report (2001) selection in Urban La Costa Greens Neighborhood 1.7 Storm Water Management Plan Proper inspection includes a visual observation to ascertain whether the unit is functioning properly and measuring the amount of deposition in the unit. Floatables should be removed and sumps cleaned when the sump storage exceeds 85 percent of capacity specifically, or when the sediment depth has accumulated within 6 inches of the dry-weather water level. The rate at which the system collects pollutants will depend more heavily on site activities than the size of the unit. Maintenance of the site BMPs will be the responsibility of the Homeowners Association. A maintenance plan will be developed and will include the following information: Specification of routine and non-routine maintenance activities to be performed A schedule for maintenance activities Name, qualifications, and contact information for the parties responsible for maintaining the BMPs For proper maintenance to be performed, the storm water treatment facility must be accessible to both maintenance personnel and their equipment and materials. 5.5 - Operations and Maintenance Plan The operational and maintenance needs of a CDS unit include: Inspection of structural integrity and screen for damage. Animal and vector control. Periodic sediment removal to optimize performance. Scheduled trash, debris and sediment removal to prevent obstruction. The facility will be inspected per the maintenance scheduling listed in Section 5.6 of this report. Inspection visits will be completely documented: Preventive maintenance activities to be instituted at a CDS are: Trash and Debris Removal - trash and debris accumulation will be monitored during both the dry and wet season and after every large storm event (rainfall events in excess of 1 inch). Trash and debris will be removed from the CDS unit annually (at the end of the wet season). Trash and debris will also be removed when material accumulates to 85% of CDS unit's sump capacity, or when the floating debris is 12 inches deep (whichever occurs first). DE:de H:\REPORTS\2352\107N1.07\SWMP05.doc W.O. 2352-107 4/20/2005 6:29 PM La Costa Greens Neighborhood 1.7 Storm Water Management Plan Sediment Removal - sediment accumulation will be monitored during both the wet and dry season, and after every large storm (1.0 inch). Sediment will be removed from the CDS unit annually (at the end of the wet season). Sediment will also be removed when material accumulates to 85% of CDS unit's sump capacity, or when the floating debris is 12 inches deep (whichever occurs first). Disposal of sediment will comply with applicable local, county, state or federal requirements. Corrective maintenance is required on an emergency or non-routine basis to correct problems and to restore the intended operation and safe function of a CDS unit. Corrective maintenance activities include: Removal of Debris and Sediment Structural Repairs - Once deemed necessary, repairs to structural components of a CDS unit will be completed within 30 working days. Qualified individuals (i.e., the manufacturer representatives) will conduct repairs where structural damage has occurred. 5.6 - Schedule of Maintenance Activities CDS PMSU 40_40_10 Target Maintenance Date - March 15*^ Maintenance Activity - Annual inspection and cleanout. Clear grit chamber unit with vactor truck. Perform visual inspection. Remove floatables. Target Maintenance Dates - 15**^ of each month; October through May (Rainy Season Inspections) Maintenance Activity - Regular inspection to ensure that unit is functioning properly, has not become clogged, and does not need to be cleared out; CDS PMSU 40_30_10 Target Maintenance Date - March 15'^ Maintenance Activity - Annual inspection and cleanouL Clear grit chamber unit with vactor truck. Perform visual inspection. Remove floatables. Target Maintenance Dates - 15'^ of each month; October through May (Rainy Season Inspections) Maintenance Activity - Regular inspection to ensure that unit is functioning properly, has not become clogged, and does not need to be cleared out; DE:de H:\REPORTS\2352\107 N 1.07\SWMP05.doc W.O. 2352-107 4/20/2005 6:29 PM La Costa Greens Neighborhood 1.7 Storm Water Management Plan 5.7 - Annual Operations & Maintenance Costs The following costs are intended only to provide a magnitude of the costs involved in maintaining BMPs. Funding shall be provided by the Home Owners Association for the La Costa Greens development. Approximate annual maintenance costs for the proposed CDS units are outlined below. Costs assume a 3 man crew: Maintenance for CDS PMSU 40_40_10: Periodic Inspection, Maintenance and Monitoring = $800 Annual Cleanout Cost = $2,250 Maintenance for CDS PMSU 40_30_10: Periodic Inspection, Maintenance and Monitoring = $800 Annual Cleanout Cost = $2,000 Subtotal = $5,850 Contingency = $585 Total = $6,435 DE:de H:\REPORTS\2352M07 N 1.07\SWMP05.doc W.O. 2352-107 4/20/2005 6:29 PM La Costa Greens Neighborhood 1.7 Storm Water Management Plan CHAPTER 6 - SOURCE CONTROL BMPS 6.1 - Landscaping Manufactured slopes shall be landscaped with suitable ground cover or installed with an erosion control system. Homeowners will be educated as to the proper routine maintenance to landscaped areas including trimming, pruning, weeding, mowing, replacement or substitution of vegetation in ornamental and required landscapes. Per the RWQCB Order, the following landscaping activities are deemed unlawful and are thus prohibited: - Discharges of sediment - Discharges of pet waste Discharges of vegetative clippings - Discharges of other landscaping or construction-related wastes. 6.2 - Urban Housekeeping Fertilizer applied by homeowners, in addition to organic matter such as leaves and lawn clippings, all result in nutrients in storm water mnoff. Consumer use of excessive herbicide or pesticide contributes toxic chemicals to mnoff. Homeowners will be educated as to the proper application of fertilizers and herbicides to lawns and gardens. The average household contains a wide variety of toxins such as oil/grease, antifreeze, paint, household cleaners and solvents. Homeowners will be educated as to the proper use, storage, and disposal of these potential storm water mnoff contaminants. Per the RWQCB Order, the following housekeeping activities are deemed unlawful and are thus prohibited: Discharges of wash water from the cleaning or hosing of impervious surfaces including parking lots, streets, sidewalks, driveways, patios, plazas, and outdoor eating and drinking areas (landscape irrigation and lawn watering, as well as non-commercial washing of vehicles in residential zones, is exempt from this restriction) - Discharges of pool or fountain water containing chloride, biocides, or other chemicals Discharges or runoff from material storage areas containing chemicals, fuels, grease, oil, or other hazardous materials - Discharges of food-related wastes (grease, food processing, trash bin wash water, etc.). OE:de H:\REPORTS\2352M07 N 1.07\SWMP05.doc W.O. 2352-107 4/20/2005 6:29 PM La Costa Greens Neighborhood 1.7 Storm Water Management Plan 6.3 - Automobile Use Urban pollutants resulting from automobile use include oil, grease, antifreeze, hydraulic fluids, copper from brakes, and various fuels. Homeowners will be educated as to the proper use, storage, and disposal of these potential storm water contaminants. Per the RWQCB Order, the following automobile use activities are deemed unlawful and are thus prohibited: Discharges of wash water from the hosing or cleaning of gas stations, auto repair garages, or other types of automotive service facilities. Discharges resulting from the cleaning, repair, or maintenance of any type of equipment, machinery, or facility including motor vehicles, cement- related equipment, port-a-potty servicing, etc. Discharges of wash water from mobile operations such as mobile automobile washing, steam cleaning, power washing, and carpet cleaning. The Homeowners Association will make all homeowners aware of the aforementioned RWQCB regulations through a homeowners' education program. 6.4 - Site Design BMPs Priority projects, such as the La Costa Greens Neighborhood 1.7 development, shall be designed to minimize, to the maximum extent practicable the introduction of pollutants and conditions of concern that may result in significant impact, generated from site mnoff to the storm water conveyance system. Site design components can significantly reduce the impact of a project on the environment The following design techniques have been proposed to accomplish this goal. - Implementing on-lot hydrologically functional landscape design and management practices; Additional detail regarding landscaping design is discussed in section 6.1. - Minimizing project's impervious footprint. Methods of accomplishing this goal include constructing streets, sidewalks, and parking lots to the minimum widths necessary without compromising public safety. Another example for minimizing impervious area includes incorporating landscaped areas in the drainage system to encourage infiltration and reduce the amount of directly connected impervious areas. - Minimizing directly connected Impervious Areas. Where landscaping is proposed, drain rooftops into adjacent landscaping priorto discharging to the storm water conveyance system. Forthe proposed 41 acre site, 6.4 acres (approximately 15.5%) will remain totally pervious. DE:da H:\REPORTS\2352M07 N 1.07WIVMP05.doc W.O. 2352-107 4/20/2005 6:29 PM La Costa Greens Neighborhood 1.7 Storm Water Management Plan CHAPTER 7 - TREATMENT CONTROL BMP DESIGN CDS TREATMENT UNITS 7.1 - BMP Locations The site design includes two CDS treatment units (shown on BMP Location Map located on the following page). The first is located at the end of the Eastern stonn drain, prior to discharging to the Alicante detention basin. The second is located at the end of the Western storm drain, prior to discharging to the Alicante detention basin. 7.2 - Determination of Design Treatment Flows The 85*^ percentile design flow rates have been calculated using the Rational Method. Required data for the Rational Method treatment flow determination include the following: - Runoff Coefficient (C) - Rainfall Intensity (I) = 0.20 inches per hour - Drainage area to treatment unit (A) Runoff coefficients were derived based upon a weighted average of each area tributary to the treatment unit and the associated runoff coefficient. The following table summarizes the parameters used for determination of design flows to each of the CDS treatment units. DESIGN RUNOFF DETERMINATION SUMMARY TABLE Treatment Unit Runoff Coefficient (C) 85*^ Percentile Rainfall (inches/hour) Drainage Area (acres) 85*^ Pet. Design Flow (cfs) West Storm Drain Unit 0.67 0.2 26.4 3.5 East Storm Drain Unit 0.56 0.2 42.3 4.7 DE:de H:\REPORTS\2352M07N1.07\SWMP05.doc W.O. 2352-107 4/20C0O5 6:29 PM /S^Ss - / i T / SCALE 1"=80' OPEN SPACS pRaeoSED''j;fiPE BROWITOH r .'>t*. -V-^ - PROPOSED'tHOmiTCH . X> PROPOSED STORU'WATER TREATUENT UNIT (TO BE HOA * . SRADHfO SETBACK. .••PER.<i:u:a PROPOSED HIGH SOUND. mUt LEGEND WATERSHED BOUNDARY FLOWLINE —- • WATER TREATMENT UNIT -PROPtSED a£ANWTS. VE.PROPOSEB'STORIIiDRAIN'AND WATMOttlMIT.TO • ,. ' m EXISTMC PIPE AND STUB PEP DRAIONC HO. 397-/2 (DgSJINS HEADWAO: TO BE REU0VE6) f-PROPOSED STORM WATER^JREATUENJ UNIT (n:aE.MOA-^IAINTA{NED-)..il .•' :• '.' . , ' . _ PREPARED BY: HUNSAKER &. ASSOCIATES SAN DIIII4 INC BIVIP LOCATION IVIAP FOR LA COSTA GREENS NEIGHBORHOOD 1.07 CITY OF CARLSBAD, CALIFORNIA Ri\Q386\I.Hyd\Q386SHQ3-BMP.dwgC 208S]Apr-20-200S>18i37 La Costa Greens Neighborhood 1.7 Storm Water Management Plan 7.3 - CDS Treatment Unit Selection Calculations show that CDS Model PMSU 40_30_10 & CDS Model PMSU 40_40_10 treatment units would be required to treat the design 85**^ percentile flow. These units are an inline system and do not require the construction of a special diversion box upstream of the treatment unit. The following table shows the treatment capacities of the proposed CDS units. CDS UNIT TREATMENT CAPACITY TABLE Treatment Unit 85'" Pet. Design Flow (cfs) Recommended CDS Model Treatment Capacity (cfs) Unit#1 3.5 PMSU 40-30-10 4.5 Unit #2 4.7 PMSU 40-40-10 6 DE:de H:\REPORTS\2352M07N 1.07\SWMP05.doc W.O. 2352-107 4/20/2005 6:29 PM 85TH PERCENTILE PEAK FLOW AND VOLUME DETERMINATION Modified Rational Method - Effective for Watersheds < 1.0 mi^ Hunsaker & Associates - San Diego Note: Only Enter Values in Boxes - Spreadsheet Will Calculate Remaining Values Project Name La Costa Greens 1.7 | Work Order 2352-107 1 Jurisdiction City of Carlsbad | BMP Location jEastern Storm Drain - Prior to discharge to Alicante Detention Basin 8Sth Percentile Rainfall = 0.67 1 (from County Isopluvial Map) Developed Drainage Area = 42.3 Natural Drainage Area = 0.0 Total Drainage Area to BMP = 42.3 Dev. Area Percent Impervious = 38 1 Overall Percent Impervious = 38 Dev. Area Runoff Coefficient = 0.56 Nat. Area Runoff Coefficient = 0.35 Runoff Coefficient = 0.56 Time of Concentration = | 17.3 | acres acres acres % (from Drainage Study) RATIONAL METHOD RESULTS Q = CIA where V = CPA where Q = 85th Percentile Peak Flow (cfs) C = Runoff Coefficient I = Rainfall Intensity (0.2 inch/hour per RWQCB mandate) A = Drainage Area (acres) V = 85th Percentile Runoff Volume (acre-feet) C = Runoff Coefficient P = 85th Percentile Rainfall (inches) A = Drainage Area (acres Using the Total Drainage Area: C = 0.56 I = 0.2 inch/hour P = 0.67 inches A = 42.3 acres Q = V = 4.74 cfs 1.32 acre-feet Using Developed Area Only: C = 1 = P = A = Q = V = 0.56 0.2 inch/hour 0.67 inches 42.3 acres 4.74 cfs 1.32 acre-feet Rational Method Results a La Costa Greens 1.7 East SD 1) % Impervious 0.45 0.55 0.85 Development Area (ac) 1.95 10.28 3.15 2.48 10.16 0.78 3.56 1.21 1.32 1.87 1.76 3.75 0 = Sum of Areas 6.4 32.7 3.2 0.0 0.0 0.0 0.0 0.0 0.0 = 42.3 ac. 38.0% impervious % Impervious 0 40 95 = 42.3 ac. 38.0% impervious Weighted Average C = 0.56 85TH PERCENTILE PEAK FLOW AND VOLUME DETERMINATION Modified Rational Method - Effective for Watersheds < 1.0 mi^ Hunsaker & Associates - San Diego Note: Only Enter Values in Boxes - Spreadsheet Will Calculate Remaining Values Project Name La Costa Greens 1.7 | Work Order 2352-107 1 Jurisdiction City of Carlsbad | BMP Location {Western Storm Drain - Prior to discharge to Alicante Detention Basin 85th Percentile Rainfall = 0.67 1 (from County Isopluvial Map) Developed Drainage Area = 26.4 Natural Drainage Area = 0.0 Total Drainage Area to BMP = 26.4 Dev. Area Percent Impervious = 57 1 Overall Percent Impervious = 57 Dev. Area Runoff Coefficient = 0.67 Nat. Area Runoff Coefficient = 0.35 Runoff Coefficient = 0.67 Time of Concentration = 11.5 1 acres acres acres (from Drainage Study) RATIONAL METHOD RESULTS Q = CIA where Q = 85th Percentile Peai< Flow (cfs) C = Runoff Coefficient I = Rainfall Intensity (0.2 inch/hour per RWQCB mandate) A = Drainage Area (acres) V = CPA where V = 85th Percentile Runoff Volume (acre-feet) C = Runoff Coefficient P = 85th Percentile Rainfall (inches) A = Drainage Area (acres Using the Total Drainage Area: C = 0.67 I = 0.2 inch/hour P = 0.67 inches A = 26.4 acres Q: V = 3.54 cfs 0.99 acre-feet Using Developed Area Only: C = I = P = A = Q = V = 0.67 0.2 inch/hour 0.67 inches 26.4 acres 3.54 cfs 0.99 acre-feet Rational Method Results a La Costa Greens 1.7 West SD 1) % Impervious 0.45 0.55 0.85 Development Area (ac) 0.53 1.55 9.70 1.76 0.73 2.60 2.10 1.98 1.18 1.67 2.60 C = Sum of Areas 5.6 8.5 12.3 0.0 0.0 0.0 0.0 0.0 0.0 = 26.4 ac. % Impervious 0 40 95 -57.2% impervious Weighted Average C = 0.67 CDS Technologies, Inc., CDS TECHNOLOGY Continuous Deflective Separation (CDS®) is an innovative technology that is revolutionizing liquids/solids separation in storm water and combined sewer overflow industry. The technology accomplishes high efficiency separation of settleable particulate matter and virtually 100 percent capture of floatable material. Its application is ideal to any situation where removal of gross pollutants is desired. The primary features of the CDS® system are: • EFFECTIVE: capturing more than 95% of solid pollutants • NON-BLOCKING: unique design takes advantage of indirect filtration and properly proportioned hydraulic forces that virtually makes tiie unit unblockable. 4 NON-MECHANICAL: the CDS® unit has no moving parts and requires no supporting mechanical package to affect soHd separation from stormwater flows. • LOW MAINTENANCE COSTS: because the system has no moving parts and is constructed of durable materials. ^ COMPACT AND FLEXIBLE: design and size flexibility enable units embodying the CDS® technology to be used in a variety of configurations and in limited spaces. ^ HIGH FLOW EFFECTIVENESS: the technology remains highly effective across a broad spectrum of flow ranges, with hydraulic loadings exceeding 80 gallons per square foot of plan surface area. ^ ASSURED POLLUTANT CAPTURE: all materials captured are retained during high flow conditions. 4 SAFE AND EASY POLLUTANT REMOVAL: extraction methods allow safe and easy removal of pollutants without manual handling. 4 COST EFFECTIVE: total costs are lower per mass material captured compared to existing available alternatives. CDS® offers small separation units to process flows of 1 cubic foot per second (cfs) or less. The smallest unit is ideal for small drainage areas such as parking lots. CDS® offers a range of premanufactured units sized to process typical drainage flows from new and existing urban developments. CDS® also offers design services for larger cast in place imits to meet the treatment requirements of more significant runoff flows generated by larger drainage areas. To date, CDS® can design units capable of processing up to 300 cfs. CDS® units are available in precast reinforced concrete modules for all applications processing flows up to 64 cubic feet per second. For appKcations requiring larger flow processing, units are designed complete with construction specifications for cast in place construction. Units can be readily adapted to pipelines, box culverts, and open channels with varying geometric shapes. CDS Technologies, Inc., CDS Technologies® includes multiple "Manhole" units in its Model lineup. These are uniquely designed for in Une use on small pipelines to 36" in diameter, where desired process flows are 6 cfs or less. The CDS® technology including its high flow bypass weir is neatly packaged inside of standard manhole stacks from 4' to 8' diameter. These particular units have been specially configured to allow an effective oil baffle system to be installed increasing the capacity to hold greater quantities of free oil should the need arise. For piping larger than 36", CDS Technologies® recommends using a standard beside line unit with a diversion weir box designed specifically to accommodate the larger pipe. HYDROLOGIC ANALYSIS In storm water applications, an analysis of tiie catchment in terms of its size, topography and land use will provide information for determining the flow to be expected for various retum periods. Based on the poUutograph (if known), a CDS® unit can be designed for tiie flow tiiat mobilizes the gross pollution in the catchment. Since there are variations in catchment response due to region, land use and topography, CDS Technologies® recommends tiie selection of a design flow for treatment having a retum period between three months and one year. Typically, it is not necessary to design CDS® units to process a conveyance system's design flow in order to achieve a very high level of pollutant removal. An effective design recognizes that the vast majority of pollutants are mobilized in flows that are well below the "design capacity" for the conveyance facility. Field evaluations to determine pollutant mobilization flows in combined sewer overflows have determined that the pollutants are released and mobilized with flows having retum periods of 3 to 6 months. The majority of pollutants in storm water are mobilized in similar events. It is well recognized that even though the three-month to one-year event is well below the average system's capacity, the actual volume that is generated in the catchment from events smaller than these is about 95% of the total annual volume generated by the catchment. It is worth noting that a VERY small quantity of solid pollution actually travels in these higher flows, therefore, from a practical perspective, designing for the three month to one year event is virtually designing to treat nearly 100% of the runoff that will be transporting pollution. HYDRAULIC DESIGN Every CDS installation requires a detailed hydraulic analysis to ensure the final installation will properly perform to effect optimum solids separation without blocking the separation screen. Proper design requires knowledge of the conveyance system, and its performance through its design flow range and the hydraulic performance of the selected CDS® unit through the same flow range. After the CDS® design flow is determined, the appropriate standard model can be selected from TABLE A on Page 6. Each model on Page 6 identifies a reference PAGE on which additional, detailed information about the selected model is available. The design flow is diverted into the CDS® imit by constructing a diversion weir across the flow path of the conveyance facility. The approximate height of the weir can be established by determining tiie hydrauhc grade Hne (HGLd/s) in the system immediately downstiream of the CDS® unit and adding tiie CDS HEAD LOSS (beds) identified on the PAGE referenced for the unit selected. The sum of the above represents the HGLu/s required at the entrance to the diversion weir. CDS Technologies, Inc., HGLu/s~ HGLd/s hcds The height of the CDS diversion weir can then be determined to be: Weir Height= HGLu/s - Invert Level Maximum Water Surface or HGL Upstream of the CDS Installation The head loss identified in the Tables on Pages 9-13 represents the ideal hydraulic installation. The head required to operate a CDS® unit at the CDS® design flow does not confrol the maximum rise in water surface upsfream of the CDS® unit. At the CDS® design flow; the HGL is at the top of the diversion weir. For most installations this is well below finished grade. The maximum increase in water surface occurs when the conveyance system reaches its design flow. When this flow occmrs, the actual flow through the CDS® may be altered, witii the balance of flow passing over the diversion weir. Based on laboratory measurements and analysis, it has been established that the actual head loss under system design flow will not exceed 1.3 x V^/2g in a well-designed diversion structure, where V is the design flow velocity in the system when tiie pipe is flowing. To assure passage of system design flow through the weir area, the unobstructed area provided above the weir must be equal to or greater than the cross sectional area for the pipehne entering the weir box. In recognition of the potential that the CDS® may fill up with captured material and lose its conveyance capacity, the hydraulic evaluation must include analysis under this scenario to mderstand the potential for flooding upsfream. The effects of the diversion weir primarily influence the rise in the water surface imder the conveyance system design flow. The actual effect can be confrolled by properly designing the weir length and clear height above the weir to take advantage of the potential energy that can be developed in the system without inducing flooding upsfream. CDS Technologies recommends that the head loss across the weir be limited to no more than 1.4 times the CDS® unit headloss at its design flow to ensure that it continues to operate properly during the conveyance system's peak flows. An example of the hydraulic design process is provided under Appendix B. STRUCTURAL DESIGN All CDS® units are designed to withstand equivalent fluid pressures that the unit may experience during its hfe. The water table at the installation site should be known, or a conservative estimate will be made on the maximum expected. Units are analyzed assuming that it is empty and full buoyant force is acting on it. The foimdation material needs to be adequate to support the structure's weight without allowing differential settlement. The materials for inanufacture of precast units are fully described in Appendix D "Product & Installation Specifications" of this Manual. All cast in place concrete designs are based on using structural concrete witii minimum ultimate sfrength of 4,000 pounds per square inch (psi), with steel 'reinforcement having a minimum ultimate yield sfrength of 60(10^) psi. Concrete and steel reinforcement are as noted in Appendix D, unless otherwise specified for site-specific conditions. CDS Technologies, Inc., CDS MODEL DESIGNATION CDS units are identified by tiieir process screen diameter. They are also identified by its appHcation witii "SW" designating "Storm Water", "SU" designating "Storm Unit" "CS" designating "Combined Sewer". Model families are designated by tiie letter 'T", PM, or "C", designating, "Precast", Precast Manhole, or "Cast" in place, along witii tiie application letters and a pafr of number designations such as PSWXX_XX. The first XX represents tiie separation screen diameter in feet; the second _XX designates tiie height of the separation screen in feet (see TABLE A on page 7 for fiirther description of unit designations). General manufacturing details and weights are included for the various models under Appendix A. CDS VARIABLE COMPONENTS The variable components in a CDS® unit witiiin a model family are tiie screen height, tiie screen aperture (opening), sump diameter and depth, and type of cover. Screen Height The screen height is important within a model family because it confrols tiie design flow that can pass through the unit witiiout clogging tiie screen. In general, screen heights can vary between 60 to 150 percent of the screen diameter. Screen Aperture The standard screen for storm water apphcations is 4700 microns (.185 inches) for coarse screening. A 2400 micron (0.095) is available where tiiere is a need to separate finer sediments than those removed by the 4700 micron screen. The screen aperture (opening) is important because it sets the capture parameter for settleable pollutants, frl general, a CDS® unit witii a 4700 micron screen will capture 93% of all particles as small as 1/3 the short dimension of the screen opening. This has been determined through extensive pilot work performed by Tony Wong, PhD, Monash University. Tony Wong's technical paper, fiilly describing tiie hydraulic basis on which CDS® achieve effective solid separation, is readily available. Sump The sump is another variable that can be adjusted for site-specific conditions and utihty preference. Each Model Family is equipped witii a standard sump. However, the diameter and depth can be adjusted to meet site-specific requfrements. CDS® Covers Covers can be provided with each CDS® unit A pedestrian traffic cover is standard with each unit. The cover is designed with an inspection/cleanout hatch. The entire cover may be removed to facilitate cleanout. If required, a frafflc bearing cover will be designed, fabricated and furnished. If a fraftic bearing cover is desired, tiie utility should so advise CDS Technologies® to include it in tiie quote. m CDS Technologies, Inc., CDS® SUMP CLEANOUT Sump cleanout is a critical component of a successful CDS® operation. The sump is the depository for all settleable pollutants captured by CDS®. The metiiods for maintenance and cleanout are generally specific, dependent on the preferences of a given agency. The standard model is provided with a standard sump that can be cleaned by methods selected by the utility. At the utility's discretion, a unit can be cleaned using a vacuum tmck or a small clamshell bucket, or a basket can be provided to fit a standard sump. If the utility chooses to use a basket, it should advise CDS Technologies so it can be included in a quote. CDS® MAINTENANCE CDS maintenance can be site and drainage area specific. The unit should be inspected periodically to assure its condition to handle anticipated runoff. If pollutant loadings are known, then a preventive maintenance schedule can be developed based on runoff volumes processed. Unfortunately, that is seldom the case. CDS Technologies recommends the following for Storm Water Apphcations: New Installation - Check the condition of the unit after every runoff event for the first 30 days. Checking includes a visual inspection to ascertain that the unit is functioning properly and measuring the amount of deposition that has occurred in the unit. This can be done with a "dip stick" that is calibrated so the depth of deposition can be fracked. Based on the behavior of the unit relative to storm events, inspections can be scheduled on projections using storm events vs. pollutant buildup. Ongoing Operation - During the wet season, the unit should be inspected at least once every thirty days. The floatables should be removed and the sump cleaned when the sump is above 85% full. At least once a year, the unit should be pumped down and the screen carefully inspected for damage and to ensure that it is properly fastened. Ideally, the screen should be power washed for the inspection. Maintenance Cycle - The standard maintenance cycle for a CDS device is a minimum of once a year. Maintenance may be required more frequently depending on the pollutant load in the drainage. However, if the actual pollutant load is properly estimated, the sump capacity can be adjusted to hold an annual pollutant load. The CDS® unit is a confined space. Properly frained people equipped with requfred safety gear will be required to enter the unit to perform the detailed inspection. TABLE — A MODEL PERFORMANCE CAPABILITY MODEL DESIGN FLOW RATE REFERENCE NUMBER CFS MOD M Vsec PAGE PMI.y_20^15 0.7 _ 0.5 .02 PMSU20_15_4 0.7 "0.5 .02 ' ' PMSU20_15 OJ 0.5 ' .02 LINE PMSU20_20 1.1 _ 0.7 .03 LINE PMSU20_25 I.e" 1.0 _ . q5_ PMSU30_20 2.0 1.3 , .^06_ 9 PMSU30_30 3.0 _ 1.9 .08 PMSU40_30 4.5 3.0 .13 PMSU40_40 6.0 3.9 ... - PSWC30_30 3.0 1.9 .08 PRECAST PSWC40_40 6.0 3.9 .17 PRECAST PSWC56_40 PSWC56_53 9.0 14" 5.8 9.0 .25 .40 bJ PSWC56_68 PSWC56_78 '19 25 12 16 .54 ".71" 10 2 _l U. PSW30_30 3.0 1.9 .08 Li_ o PSW50_42 9.0 5.8 .25 PSW50_50 11 7.1 .31 PSW70_70 26 17 .74 PSW100_60 30 19 .85 11 PSW100_80 50 32 1.4 PSW100_100 64 41 1.8 LU o Q. CSW150_134 148 95 4.2 CAST LU o Q. CSW200_164 270 174 7.6 12 CSW240_150 300 194 8.5 Conversion: Icfs = 0.0283 cubic meters per second, or 1 M /sec = 35.31 cfs Icfs S 0.64512 MOD or 1MGD = 1.55 cfs MODEL DESIGNATIONS Screen Diameter — Screen Height PMSU= Precast Manhole Storm Water Unit PSWC= Precast Storm Water Concentric PSW = Precast Storm Water CSW =Cast in Place Storm Water J Feet. Tenths of a Foot * L or' R designates the location of the CDS when looking downstream. (L)eft represents being placed on the Left side of the stormdroin, fRVnht is nlnrfiH on the right side. X X _ X X (L or .R)* Tenths of a Foot - Feet GENERAL DESCRIPTION OF UNIT HIGH FLOW BYPASS •WEIR BOX- CONVEYANCE CONDUIT SEPARATION SCREEN INLET DIVERSION WEIR CONVEYANCE CONDUIT OUTLET CONTROL WEIR CDS OUTLET SEPARATION CHAMBER — PLAN VIEW (RIGHT HAND UNIT) TCCHNOLOGIES GENERAL DESGRIPTION OF INLET DIVERSION WEIR EXISTING GRADE HIGH FLOW BYPASS CONVEYANCE CONDUIT CONVEYANCE CONDUIT SEPARATION CHAMBER SEPARATION SCREEN SUMP ELEVATION TECHNOLOGIES f I PRECAST MANHOLE MODELS PROCESSES FLOWS 0.75 TO 6.5 CFS R.OW VARIES 1 • FUTrf A = FOOT PRINT DIAMETER D = DEPTH BELOW PIPE INVERT. VARIES PRECAST MODEL NUMBER **TREATMENT DESIGN FLOW RATE ***DESIGN HEAD LOSS @ DESIGN TREATMENT FLOW RATE SCREEN DIA./HT. DEPTH BELOW PIPE INVERT "D" FOOT PRINT DIAMETER "A" PRECAST MODEL NUMBER cfs MGD m ^/sec ft. m ft. ft. •ft. PMIU20_15 0.7 0.5 0.02 0.45 0.11 2/1.5 4.2 4.8 PMSU20_15_4 0.7 0.5 0.02 0.35 0.11 2/1.5 3.5 - 4 4.8 PMSU20_15 0.7 •• 0.5 0.02 0.35 0.11 2/1.5 5.1 6.0 PMSU20_20 1.1 0.7 0.03 0.48 0.15 2/2.0 5.7 6.0 PMSU20_25 1.6 1.0 0.05 0.62 0.19 2/2.5 6.0 6.0 PMSU30_20 2.0 1.3 0.06 0.65 0.20 3/2.0 6.2 7.2 PMSU30_30 3.0 1.9 0.08 0.70 0.21 3/2.8 7.2 7.2 PMSU40_30 4.5 3.0 0.13 0.85 0.26 4/3.0 8.6 9.5 PMSU40_40 6.0 3.9 0.17 0.88 0.27 4/4.0 9.6 9.5 ! I I *Standard screen opening is 4700 microns (.185 in.). Screens also available in 2400 microns (.095 in.). **This is the minimum flow that will receive treatment before bypass is allowed. These precast manhole units ore capable of by passing the 025 year event. CDS Engineers are readily available to provide hydraulic consultations on all applications. ***The headloss during a bypass event is a function of the velocity head. 1.3 to The typical coefficient of headloss 2.5 = 'K CDS ranges from PLAN VIEW CDS MODEL PMSU40_30, 4.5 CFS TREATMENT CAP. ELEVATION VIEW SEE SHEET 2 I I I ! I I I I ! ! I DPTIDNAL DIL BAFFLE C STDRM PIPE XX'0 OUTLET PIPE 30'?i MH FRAME AND COVER (TYPICAL) ALTERNATIVE ACCESS HATCH SYSTEMS READILY AVAILABLE FIBERGLASS INLET 96' ID CONC, 'MH RISER CONCRETE TOP CAP -XX'0 INLET PIPE ELEVATION VIEW SEE SHEET 2 NOTE: 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). TM TECHNOLOGIES PROJECT/ DEVELOPMENT NAME CITY k STATE DATE 3/24/00 DRAWN APPRDV. SCALE 1"=3' SHEET 1 ELEVATION VIEW CDS MODEL PMSU40_30, 4..5 CFS TREATMENT CAP. p p p I XX'SS MH COVER il . FRAME- ALTERNATIVE ACCESS. HATCHES AVAILABLE GROUT DR USE GRADE RINGS AS NECESSARY C SEPARATION SECTION G RISER , SECTIONS OUTLET PIPE" VARIES I nNISHED GRADE EL=XX.XX' VARIES 12" TYP./ -8"-0" 4 •• -OIL BAFFLE I- VARIES INLET 'PIPE 4.O'0 _ "SCREEN 42,5 i'2" "ryp. 28"0 SUMP OPENING SUMP 36- (TYPICAL) PIPE INVERT EL=XX.XX' 8'-7- 1 •• I -9-6"- SUMP BOTTOM EL=XX.XX' TM TECHNOLOGIES PATENTED PROJECT/ DEVELOPMENT NAME CITY & STATE DATE 3/24/00 DRAWN APPRDV. SCALE 1 "=3' SHEET I I i p P P p p p SECTION VIEW CDS MODEL PMSU40_30, 4.5 CFS TREATMENT CAP. XX"0 OUTLET PIPE ROTO-HAMMER OR SAW CUT OPENINGS FOR PIPE INLET AND OUTLET AS NECESSARY OIL BAFFLE C STDRM PIPE ROTATE SEPARATION SLAH TO OBTAIN INDICATED OFFSET DISTANCES FL^NGES ON INLET SIDES dc BOTTOM ATTACHED TO RISER WALL USING 6 ANCHOR BOLTS MINIMUM-(SUPPUED BY CDS TECHNOLOGIES) CENTER OF 96** MH RISER SECTIONS CENTER OF SCREEN, 2B"0 SUMP OPENING 48"* SEPARATION SCREEN^ SEE NOTE NO. 2 ATTACH SCREEN TO S\JB USING 4 ANCHOR BOLTS, SUPPUED BY CDS. ACCESS RISER, a'-O" I.D. XX"* INLET PIPE 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 1NSTALL\T10N, GREEN FUNGE ON SCREEN FACES UP. TM TECHNOLOGIES PATENTED PROJECT/ DEVELOPMENT NAME CITY k STATE DATE 3/24/00 DRAWN APPRDV. SCALE r=2.5' SHEET 3 PLAN VIEW CDS MODEL PMSU40_40, 6 CFS TREATMENT CAP. CONCRETE TOP CAP 24"*MH FRAME AND COVER (TYP.). ALTERNATA/E ACCESS COVERS READILY AVAlU>aL£ OIL BAFFLE ELEV. VW. (SEE SHEET 2) ELEV. VW. (SEE SHEET 2) C STORM DRAIN I 8'-0" ID CONC. MH. (9-6" OD) XX"* RCP OUTLET 30"*MH FRAME AND COVER OYP.), ALTERNATIVE ACCESS COVERS READILY AVA1L^BLE NOTE: THE INTERNAL COMPONENTS ARE SHOWN IN THE RIGHT-HAND CONFIGURATION-THESE COMPONENTS MAY BE FURNISHED IN THE MIRROR IMAGE TO THAT SHOWN (LEFT-HAND CONRGURATION). TECHNOLOGIES PATENTED PROJECT/ DEVELOPMENT NAME CITY k STATE DATE 12/3/01 DRAWN W. LORSCHEIDER APPRDV, SCALE 1 "=3' SHEET 1 ELEVATION VIEW CDS MODEL PMSU40_40, 6 CFS TREATMENT CAP. ROTATE SEPARATION SLAB TO OBTAIN INDICATED OFFSET DISTANCES ACCESS RISER. B'-O" LD. INLET FLANGE FASTENED USING 6 ANCHORS, MIN. (SUPPLIED BY CDS) XX"s5 RCP INLET OIL BAFFLE CENTER OF 96"* MH RISER SECTIONS CENTER OF SCREEN, 28'* SUMP OPENING XX"* RCP OUTLET I I I CORINGS PROVIDED BY PRECASTER ATTACH SCREEN TO SL^B USING 4 ANCHOR BOLTS, (SUPPLIED BY CDS). C STORM DRAIN 48" 0 SCREEN, SEE NOTE NO. 2 DATE 12/3/01 SCALE 1"=2.5' DRAWN W. LORSCHEIDER SHEET 2 APPRDV, SHEET 2 TM TECHNOLOGIES PATENTED PROJECT/ DEVELOPMENT NAME CITY k STATE I I I I ! SECTION VIEW CDS MODEL PMSU40_40, 6 CFS TREATMENT CAPACITY C SEPARATION ^ SECTION APPLY RAM-NEK MASTIC ROPE OR EQLllVALEhfT TO SEAL ALL RISER JOINTS 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 INSTALUTION. GREEN FLANGE ON SCREEN FACES UP. TM TECHNOLOGIES PATENTED PROJECT/ DEVELOPMENT NAME CITY k STATE DATE 12/3/01 SCALE 1"=3.5' DRAWN W. LORSCHEIDER SHEET 3 APPROV. SHEET 3 I I I I I C SEPARA7K3N SECTX3N CONSTRUCTION NOTES APPLY RW-NEK MASIE ROPE OR EQUlVALEWr TD SEM. AU. RISER JQNIS 1. APPLY BUIYL MASTIC AND/OR GROUT TO SEAL JOINTS OF MANHOLE STRUCTURE. APPLY LOAD TQ MASTIC SEAL IN TO'ToWU^Nf IN^E^TMlNl^UMr"^"""" " ^^^^f^ ^^HT. HOLDING WATER UP 2. IF SEPARATION SUB IS NON-INTEGRAL TO THE SEPARATION SECTION OF THE UNFT, SET AND VERIFY TOP ELEVATION BEFORE PLACING MORE PRECAST COMPONENTS OR BACKHLLING. ENSURE 55" FROM TOP OF SEPARATION SLAB TO PIPE INVERT. '^r ur ccrrttviiiuiN ^LAH GROUT PIPE CONNECTIONS TO SEAL JOINT. SET BOTTOM OF OIL BAFFLE 32" ABOVE SEPARATION SLAB aOOR; DRILL AND INSERT A MINIMUM OF FOURTEEN (14) r X 3 r SS EXPANSION BOLTS © 12 O.C. EQUALLY SPACED TO SECURE BAFFLE FLANGE TO RISER WALL- (HARDWARE SUPPUED BY CDS TECHNOLOGIES). 5. FASTEN FIBERGLASS CYUNDER/INLET TO SCREEN ASSEMBLY USING FOUR (4) SETS OF 4" x 1 4" SS HEX HEAD BOLTS W/ NUTS AND WASHERS-(HARDWARE SUPPLIED BY CDS TECHNOLOGIES). IN THE LEFT-HANDED CONFIGURATION THE "RED" COLORED FUNGE ON THE SCREEN CYLINDER SHALL FACE UP. IN THE RIGHT-HANDED CONFIGURATION. THE "GREEN" COLORED FUNGE SHALL FACE UP. DRILL AND INSERT A MINIMUM OF SIX (6) g" x 3 J" SS EXPANSION BOLTS EQUALLY SPACED TO SECURE RBERGUSS INLET FLANGE TO RISER WALL-(HARDWARE SUPPLIED BY CDS TECHNOLOGIES) VERIFY THAT SCREEN ASSEMBLY IS CENTERED OVER SUMP ACCESS HOLE AND ADJUST IF NECESSARY FASTEN SCREEN TO SEPARATION SLAB USING FOUR (4) g" x 3 5" SS EXPANSION BOLTS-(HARDWARE SUPPUED BY CDS TECHNOLOGIES). BLOCK AND GROUT SE^L TO MATCH GRADE AS REQUIRED. 6. a. TM TECHNOLOGIES •PATENTED PMSU40_40 CONSTRUCTION NOTES DATE 12/3/01 DRAWN J.S.F. APPRDV. SCALE N.T.S. SHEET 4 La Costa Greens Neighborhood 1.7 Storm Water Management Plan Chapter 8 - FISCAL RESOURCES 8.1 - Fiscal Mechanism Selection The table below illustrates the maintenance mechanism selection criteria and its associated fiscal funding source. The shaded portion of the table highlights the mechanism associated with the La Costa Greens 1.7 Development. »»»»»»»Increased risk, complexity, cost or other maintenance factors»»»»»»»»> (Private Responsibility) (Public Responsibility) First Category Second Category Third Category Fourth Category Importance of Maintenance Minimal concern; inherent in BMP or property stewardship Need to make sure private owners maintain, and provide County ability to step in & perform maintenance Warrants Flood Control Dist. (FCD) assuming responsibility, with funding related to project Broader public responsibility for maintenance and funding (beyond project) Tvpicai BMPs Biofllter (Grass swale, grass strip, vegetated buffer); Infiltration basin/trench [First cat. plus:] Minor wetland swale; Small detention basin; Single storm . drain insert / Oil- water separator / Catch basin insert & screen [Second cat. plus:] Wetland swale or bioretention; Detention basin (extended/dry); Wet ponds & wetlands; Multiple storm drain inserts; Filtration Systems [Third cat. plus:] Retrofit public storm drain inserts, etc. Master plan facility that serves area larger than project Mechanisms 1. Stormwater Ordinance requirement [section 67.819(a)&(b)], with code enforcement 2. Nuisance abatement with costs charged back to property owner 3. Condition In ongoing permit such as a Major Use Permit (if project has MUP) 4. Notice to new purchasers [67.819(e)] ^. Subdivision public report "white W~ papers" to include notice of maintenance responsibility 1. Dedication to FCD. 2. Formation of benefit area 3. FCD maintenance documentation 1. Dedication to FCD or County. 2. FCD/County maintenance documentation Mechanisms 6. Recorded easement agreement w/covenant binding on successors 1. Dedication to FCD. 2. Formation of benefit area 3. FCD maintenance documentation 1. Dedication to FCD or County. 2. FCD/County maintenance documentation Funding Source(s) None necessary Security (Cash deposit, Letter of , Credit, or other iacceptable to fCounty) for interim period. Agreement for security to contain provisions for release or refund, if not used. Start-up interim: Developer fee covering 24 months of costs Permanent: FCD Assessment per FCD Act Sec 105-17.5 Varies: gas tax for BMP in road ROW, Transnet for CIP projects. Special funding or General funding for others. DE:de H:\REPORTS\2352\107N 1.07\SWMP05.doc W.O. 2352-107 4/20/2005 6:29 PM La Costa Greens Neighborhood 1.7 Storm Water Management Plan 8.2 - Agreements (Mechanisms to Assure Maintenance) There are two (2) CDS units on the proposed La Costa Greens 1.7 site for storm water quality treatment. Storm water quality units fall within maintenance category two based on the City's Guidelines forthe Stormwater Maintenance Plan. Funding for all water quality treatment devices is provided by the Home Owners Association of the La Costa Greens development. The Home Owners Association will be responsible to perform the maintenance activities and to ensure adequate funding. The maintenance agreement(s) will be found with the Home Owners Association's secretary. The City of Carisbad Watershed Protection, Stormwater Management, and Discharge Control Ordinance require ongoing maintenance of BMPs to ensure the proper function and operation of theses BMPs. Costs for this maintenance will be the responsibility of the Home Owners Association at the time of inception and by the contractor during construction of the development. The treatment unit will require maintenance activities as outlined in Section 5 of this report. The approximate total annual cost for maintenance will be $6,435 for the CDS units (refer to Chapter 5). OE:de H:\REPORTS\2352\107 N 1.07\SWMP05.doc W.O. 2352-107 4/20/2005 6:29 PM La Costa Greens Neighborhood 1.7 Storm Water Management Plan CHAPTER 9 - REFERENCES "Standard Urban Storm Water Mitigation Plan - Storm Water Standards", City of Carisbad, April 2003. "Standards for Design and Construction of Public Works Improvements in the City of Carlsbad", City of Carisbad, California; April 1993. "Master Drainage and Storm Water Quality Management Plan", City of Carisbad, California; March 1994. 'TM Drainage Study for La Costa Greens Neighborhood 1.7", Hunsaker & Associates San Diego, Inc.; November, 2004. 'TM Drainage Study for La Costa Greens Neighborhood 1.6", Hunsaker & Associates San Diego, Inc.; November, 2004. "Drainage Study for La Costa Greens Neighborhoods 1.06 & 1.07", Hunsaker & Associates San Diego, Inc.; January 2005. "Hydrology Manual", County of San Diego Department of Public Works - Flood Control Division; Updated April 1993. "San Diego County Hydrology Manual", County of San Diego Departiment of Public Works - Flood Control Section; June 2003. "Order No. 2001-01, NPDES No. CAS0108758 - Waste Discharge Requirements for Discharges of Urban Runoff from the Municipal Separate Storm Sewer Systems (MS4s) Draining the Watersheds of the County of San Diego, the Incorporated Cities of San Diego County, and San Diego Unified Port Distnct" California Regional Water Quality Control Board - San Diego Region; February 21, 2001. "Water Quality Plan forthe San Diego Basin", California Regional Water Quality Control Board - San Diego Region, September 8, 1994. "CDS Storm Water Pollution Control Technical Manual", CDS Technologies, Revised April 2001. DE:d8 H:\REPORTS\2352\107 N 1.07\SWMP05.doc W.O. 2352-107 4/20/2005 6:29 PM