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HomeMy WebLinkAboutCT 02-14-03; BRESSI RANCH PLANNING AREA 8 UNIT 3; WATER QUALITY TECH REPORT; 2004-03-010 -cs WATER QUALITY TECHNICAL REPORT BRESSI RANCH RESIDENTIAL PLANNING AREA 8 CITY OF CARLSBAD, CA MARCH 2004 PROJECT NUMBER: CT 02-14(3) DRAWING NUMBER: 413-8A Prepared For: GREYSTONE HOMES 1525 Faraday, Suite 300 Carlsbad, CA 92008 PROJECTDESIGN CONSULTANTS PLA.VNLN'G • EW1R0N.MENT.41 • E.VGWEERING • SURVll/d'PS 701 B Sirool, Suite 800, San Diego, CA 92101 619-2:iS-6471 FAX 619-2.?4-0.349 Job No. 2407.40 lames M. Kllgore, ^ RCE 4669 Ition Expires 06/30/07 w TABLE OF CONTENTS 1. INTRODUCTION 1 2. PROJECT DESCRIPTION 2 3. POLLUTANTS AND CONDITIONS OF CONCERN 3 Anticipateci and Potential Pollutants from the Project Area 3 Pollutants of Concem in Receiving Waters 3 Beneficial Uses 3 Impaired Water Bodies 5 Watershed Pollutants of Concern 5 Conditions of Concem 5 4. STORM WATER BEST MANAGEMENT PRACTICES 7 Site Design BMPs 7 Source Control BMPs 7 Project-Specific BMPs 9 Structural Treatment BMPs 9 Detention Basins 11 Filtration Systems 11 Hydrodynamic Separator Systems 14 BMP Selection 15 BMP Plan Assumptions 16 5. PROJECT BMP PLAN IMPLEMENTATION 18 Construction BMPs 18 Recommended Post-Construction BMP Plan 18 Operation and Maintenance Plans 19 6. PROJECT BMP COSTS AND FUNDING SOURCES 20 TABLES Table 1. Anticipated Conditions - Anticipated Pollutants and Sources 3 Table 2. Beneficial Uses for Inland Surface Waters 4 Table 3. Beneficial Uses for Groundwater 4 Table 4. Structural BMP Selecfion Matrix 10 Table 5. BMP Design Criteria ]7 Table 6. Post-Construction BMP Summary 19 Table 7. BMP Costs 20 APPENDICES 1. Storm Water Requirements Applicability Checklist 2. Project Maps 3. Drainage Calculafions 4. Supplemental BMP Informafion 5. References 1. INTRODUCTION This Water Quality Technical Report (WQTR) was prepared to define recommended project Best Management Practice (BMP) options that satisfy the requirements identified in the following documents: • City of Carlsbad Standard Urban Storm Water Mitigation Plan, Storm Water Standards, • County of San Diego Watershed Protection, Storm Water Management and Discharge Control Ordinance (County Ordinance), • Standard Specificafions for Public Works Construcfion, • NPDES General Permit for Storm Water Discharges Associated with Construcfion Activity, and • San Diego Municipal NPDES Storm Water Permit (Order Number 2001-01). Specifically, this report includes the following: • Project description and location with respect to the Water Quality Control Plan for the San Diego Basin (Basin Plan); • BMP design criteria and water quality treatment flow and volume calculations; • Recommended BMP options for the project; • BMP device information for the recommended BMP options; and • Operation, maintenance, and funding for the recommended BMPs. Aq!r-pa8-doc 2. PROJECT DESCRIPTION This WQTR is provided for Bressi Ranch Residential Planning Area 8. The project is located in the City of Carlsbad and is part of the Bressi Ranch development. The project site is bounded by Open Space 2 and Gardenlane Way to the north, Planning Area 11 to the west and south, and Planning Area 9 to the east and south. The vicinity and site maps are available in Appendix 2. The total project site consists of 22.2 acres. The project consists of the construction of 95 single family homes and associated roadways, utilities, and landscaping. The project area currently consists of mass graded pads per the Bressi Ranch Mass Grading project. wqir-paS doc 2- 3. POLLUTANTS AND CONDITIONS OF CONCERN Anticipated and Potential Pollutants from the Project Area Based on land use, potenfial pollutants from the site under existing conditions include sediment, nutrients, trash and debris, and pesticides. Anticipated pollutants from the site under proposed conditions include bacteria, sediment, nutrients, trash and debris, oil and grease, oxygen demanding substances, and heavy metals. TABLE 1. ANTICIPATED CONDITIONS - ANTICIPATED POLLUTANTS AND SOURCES Area Anticipated Pollutants Landscaped areas Sediment, nutrients, oxygen demanding substances, pesticides Rooftops Sediment, nutrients, trash and debris Parking/driveways Sediment, heavy metals, trash and debris, oil and grease General use Sediment, trash and debris, bacteria and viruses Trash storage areas Sedjment, trash and debris, bacteria and viruses Pollutants of Concern in Receiving Waters The Bressi Ranch Residential Planning Area 8 Project is located m the Carlsbad Watershed (Hydrologic Unit 904.51) and is tributary to San Marcos Creek.' The sections below provide the beneficial uses and identification of impaired water bodies within the project's hydrologic area. Beneficial Uses The beneficial uses of the inland surface waters and the groundwater basins must not be threatened by the project. Tables 2 and 3 list the beneficial uses for the surface waters and groundwater within the project's hydrologic area. Water Quality Control Plan for the San Diego Basin. San Diego Regional Water Quality Control Board A. qlr-pa8.doc TABLE 2. BENEFICIAL USES FOR INLAND SURFACE WATERS Surface Water MUN AGR IND RECl REC2 WARM WILD San Marcos Creek -1-• • • • • TABLE 3. BENEFICIAL USES FOR GROUNDWATER Hydrologic Unit, Hydrologic Area MUN AGR IND 904.51 • • • Source: Water Quality Control Plan for Ihe San Diego Basin, September 1994 Notes for Tables 2 and 3: • = Existing Beneficial Use o = Potential Beneficial Use + = Excepted from Municipal MUN - Municipal and Domestic Supply: Includes use of water for community, miliiary. or individual water supply systems including, but not limited to, drinking water supply. AGR - Agricultural Supply: Includes use of water for farming, horticulture, or ranching mcluding, but not limited J to, irrigation, stock watering, or support of vegetation for range grazing. IND - Industrial Services Supply: Includes use of water for industrial activities that do not depend primarily on water quality including, but not limited to, mining, cooling water supply, hydraulic conveyance, gravel washing, fire protection, or oil well re-pressurization. RECl - Contact Recreation: Includes use of water for recreational activities involving body conlact with water where ingestion of water is reasonably possible. These uses include, but are not limited to. swimming, wading, water-skiing, skin and SCUBA diving, surfing, white water activities, fishing, or use of natural hot springs. REC2 - Non-Contact Recreation: Includes use of water for recreation involving proximity to water, but not normally involving body contact with water wbere ingestion of water is reasonably possible. These uses include, but are not limited to. picnicking, sunbathing, hiking, camping, boating, tide pool and marine life study, hunting, sightseeing, or aesthetic enjoyment in conjunction with the above activities. WARM - Warm Freshwater Habitat: Includes uses of water that support warm water ecosystems including, but not limited to, preservation or enhancement of aquatic habitats, vegetation, fish or wildlife, including invertebrates. WILD-Wildlife Habitat: Includes uses of water that support terrestrial ecosystems including but not limited to, preservation and enhancement of terrestrial habitats, vegeiation. wildlife, (e.g.. mammals, birds, reptiles, amphibians, invertebrates), or wildlife and food sources. w qlr pa8 doc Impaired Water Bodies Section 303(d) of the Federal Clean Water Act (CWA, 33 USC 1250, et seq., at 1313(d)), requires States to identify and list waters that do not meet water quality standards after applying certain required technology-based effluent limits (impaired water bodies). The list is known as the Section 303(d) list of impaired waters. The proposed project is not directly tributary to a 303(d) listed water body. The closest impaired water body is the Pacific Ocean Shoreline, San Marcos HA. The Pacific Ocean Shoreline, San Marcos HA is 303(d) listed for bacteria. In addifion to the Section 303(d) list of impaired waters, the State of California also identifies waters of concern that may be included on the 303(d) list in the very near future. These waters have some indications that they are impaired, but there is currently insufficient data to meet the requirements for inclusion on the 303(d) list of impaired waters. This list is known as the Monitoring List (2002). The proposed project is not directly tributary to a Monitoring List (2002) water body. The closest Monitoring List (2002) water body is the Aqua Hedionda Lagoon. The Aqua Hedionda Lagoon is listed for dissolved copper and selenium. Watershed Pollutants of Concern The proposed project is located within the Carlsbad Watershed. According to the Carlsbad Watershed Urban Runoff Management Program, the pollutants of concern for the Carlsbad Watershed are bacteria, diazinon, sediment, total dissolved solids, and nutrients. Conditions of Concern A drainage study was conducted by a California Registered Civil Engineer (RCE) to identify the conditions of concem for this project. The drainage calculations are available in Appendix 3. Following is the summary of findings from the study: • Drainage Pattems: wqitpaSdoc -5- Under existing conditions, mnoff from the project area sheet flows to the southwest and into desilting basins before entering the backbone storm drain system for the Bressi Ranch development. The backbone storm drain system discharges into a detention basin before entering an unnamed creek which eventually reaches San Marcos Creek. Under proposed conditions, the majority ofthe storm water sheet flows to the south and west and into the onsite storm drain system for Planning Area 8, except for the lots on the east side of Leighton Lane (the westem edge of PA 8), which flow to the west and into the onsite storm drain system for Planning Area 11. Both onsite storm drain systems connect directly to the backbone storm drain for the Bressi Ranch development. Soil Conditions and Imperviousness: The project area consists of soil group D. Under existing conditions, the project area is under 5% impervious and the mnoff coefficient is 0.45. Under the proposed conditions, the project area will be 69.5% impervious and the overal] runoff coefficient is expected to be 0.55. Rainfall Runoff Characteri.stics: Under exisfing conditions, the project area generates approximately 16.9 CFS (2-year storm) and 22.7 CFS (10-year storm) of storm water mnoff. Under the proposed conditions, the site will generate approximately 27.9 CFS (2- year storm) and 35.2 CFS (10-year storm) of storm water mnoff. Downstream Conditions: There is no expected adverse impact on downstream conditions as existing drainage pattems will be maintained. The detention basins at the southem ends ofthe Alicante Street and El Fuerte Street storm drains will reduce the impact ofthe increase in storm water flows due to the development. The water quality will be improved by the development through the implementation of site design, source control, and treatment BMPs. The outfall from the existing pipes is designed to protect against high velocity erosion in the proposed condition. wqlr-pa8.doc -6- 4. STORM WATER BEST MANAGEMENT PRACTICES The City Storm Water Standards Manual (Section III.2) requires the implementation of applicable site design, source control, project-specific, and stmctural treatment control BMPs. Site Design BMPs The following BMPs were considered in the project design process: • Reduce impervious surfaces, • Conserve natural areas, • Minimize directly connected areas, and • Protect slopes and channels. Some ofthe specific site design BMPs incorporated into this project indude: • Protect slopes and channels o All slopes will be stabilized with hydroseed or equivalent erosion control measures. o The outfalls are equipped with a D-41 energy dissipater and/or a riprap pad to prevent high velocity erosion. • Water quality feature o The water quality feature will direct a portion of the storm water from Village Green Dnve into a grass swale. The storm water will be directed to the Town Garden Road storm drain system at the end ofthe swale, but it is not adequate to provide treatment to the level required by the City Storm Water Standards. Source Control BMPs The following BMPs were considered in the project design process: • Inlet stenciling and signage. wqtj paS doc • Materials storage, • Trash storage, • Efficient irrigafion, and • Integrated pest management principles. Some ofthe specific source control BMPs incorporated into this project include: • Inlet stenciling and signage o All inlets within the project boundaries will be stenciled or stamped with "No Dumping - I Live Downstream," or as approved by the City Engineer. • Covered trash storage o All trash storage is covered due to the design of the standard-issue residentia] City of San Diego automated refuse containers. • Efficient irrigation o All Home Owners' Association (HOA) maintained landscaped areas will include rain shutoff devices to prevent irrigation during and after precipitation, and the irrigation will be designed for the area specific water requirements. Flow reducers and shutoff valves triggered by pressure drop will be used to control water loss from broken sprinkler heads or lines. • Storm water education o Educational materials on storm water issues and simple ways to prevent storm water pollution will be made available to residents. • Integrated pest management principles o Residents and groundskeepers will be educated on pest management principles. wqn-paS-doc o In HOA areas, only professional pest controllers will be used for the application of pesticides. Materials on how to control pests using non-toxic methods will be made available to maintenance personnel. Project-Specific BMPs The City Storm Water Standards Manual requires specific BMPs if the project includes private roads, residential driveways and guest parking, dock areas, maintenance bays, vehicle and equipment wash areas, outdoor processing areas, surface parking areas, non-retail fueling areas, or steep hillside landscaping. The Bressi Ranch Residenfial Planning Area 8 Project has residential driveways and private roads. The City Storm Water Standards Manual lists five options for residential driveways and three options for private roads. The Bressi Ranch Residentiai Planning Area 8 Project does not indude any of these options. However, the intent of the Storm Water Standards is to reduce the discharge of pollutants from storm water conveyance systems to the Maximum Extent Practicable (MEP statutory standard) throughout the use of a devdoped site. The Bressi Ranch Residential Planning Area 8 Project meets this objective by including treatment BMPs before discharging to the unnamed creek. [Structural Treatment BMPs The target pollutants, removal efficiendes, expected flows, and space availability determine the sdection of stmctural treatment BMP options. Table 4 is a sdection matrix for stmctural treatment BMPs based on target pollutants and removal efficiendes. 'vqir paS doc TABLE 4. STRUCTURAL BMP SELECTION MATRIX I Treatment Control BMP Cateeories W Pollutant Categories Biofilters Detention Basins Infiltration Basins*'^ Wet Ponds or Wetlands Drainage Inserts Filtration Hydrodynamic Separator Systems*^^ Sediment M H H H L H H Nutrients L M M M L M L Heavy Metals M M M H L H L Organic Compounds U U U U L M L Trash & Debris L H U U M H H Oxygen Demanding Substances L M M M L M L Bacteria U U H U L M L Oil & Grease M M U u L H L pesticides U U U u U L Notes for Table 4: (1) Including trenches and porous pavement (2) Also known as hydrodynamic devices and baffle boxes L: Low removal efficiency M: Medium removal efficiency H: High removal efficiency U: Unknown removal efficiency The target pollutants for this project in order of general priority are sediment (with attached materials such as bacteria and virases, nutrients, pestiddes, and metals), oxygen demanding substances, trash and debris, and oil and grease. Based on the target pollutants and typical removal effidendes, the treatment BMP options to consider indude detention basins, infiltration basins, wet ponds, filtration and hydrodynamic separator systems. The soil characteristics and the onsite drainage patterns for Planning Area 8 make infiltration basins and wet ponds infeasible for this project. wqtr-paS doc 10 Detention Basins Detention basins (a.k.a. dry extended detention ponds, dry ponds, extended detention basins, detention ponds, extended detention ponds) are basins with controlled outlets designed to detain storm water mnoff, allowing particles and associated pollutants to settle. Detention basins may be designed to include vegetation, allowing for further pollutant removal through infiltration and natural pollutant uptake by vegetation. Detention basins are among the most widely applicable storm water management practices. They should be used for drainage areas of at least 10 acres, and they can be used with almost all types of soils and geology. Detention basins for improving water quality can also be designed and used as flood control devices. Based on the size ofthe Bressi Ranch devdopment and proposed site plan, detention basins are a feasible option for treating the storm water mnoff from this project. However, the detention basin for Bressi Ranch will not be used for water quality purposes since the basin was designed for detention purposes only. ^Filtration Systems Flitration systems indude bioretention, sand and organic filters, and proprietary devices.^ Biorelenlion Bioretention areas are landscape features designed to provide treatment of storm water mnofL These areas are typically shallow, landscaped depressions, located within small pockets of residentia] land uses. During storms, the mnoff ponds above the mulch and soil of the bioretention system. The mnoff filters through the mulch and soil mix, typically being collected in a perforated underdrain and returned to the MS4. National Menu of Best Management Practices for Storm Water Phase II. US EPA. v.qtr-pa8 doc - I I - Sand and Organic Filters For sand and organic filtration systems, there are five basic storm water filter designs: • Surface sand filter: This is the original sand filter design with the filter bed and sediment chamber placed aboveground. The surface sand filter is designed as an offline system that receives only the smaller water quality events. • Underground filter: This is the original sand filter design with the filter bed and sediment chamber placed underground. It is an offline system that receives only the smaller water quality events. • Perimeter filter: This is the only filtering option that is an online system with an overflow chamber to accommodate large storm events. • Organic media filter: This is a slight modification to the surface sand filter, with the sand medium replaced with or supplemented by an organic medium to enhance pollutant removal of many compounds. • Multi-Chamber Treatment Train: This is an underground system with three filtration chambers designed to achieve very high pollutant removal rates. Proprietary Devices Proprietary filtration devices indude offline filtration systems, online filter units, and filtration based inlet inserts. Proprietary catch basin insert devices contain a filtering medium placed inside the stormwater system's catch basins. The insert can contain one or more treatment mechanisms, which include filtrafion, sedimentafion, or gravitafional absorption of oils. The water flows into the inlet, through the filter, where pollutants and contaminants are removed, and then into the drainage system. There are two primary designs for inlet inserts. One design uses fabric filter bags that are suspended in place by the grate or by retainer rods placed across the catch basin. The fabric filter design includes a skirt that directs the storm water flow to a pouch that may be equipped with rt qrr pa8 doc - 12 - oil-absorbing pillows. These inlet inserts are typically equipped with "Bypass Ports" to prevent flooding during large storm events. Maintenance on the fabric filter inserts includes periodic inspection and replacement of the entire insert when it becomes clogged with captured pollutants. The other design for inlet inserts uses stainless steel, High-Density Polyethylene (HDPE), or other durable materials to form a basket or cage-like insert placed inside the catch basin. This basket contains the filter medium and absorbent materials that treat the storm water as it passes through. These inlet inserts are also equipped with bypass pathways to allow normal operation of the storm drain system during large storm events. Maintenance on the basket-type inlet inserts indudes periodic inspection and removal and replacement of the filter medium and absorbent materials (not the enfire inlet insert). There are several types of proprietary inlet inserts for both design types: • Fabric Filter Bag Design o Stream Guard: Stream Guard works by initially capturing sediment and trash and debris, and then combats dissolved oil, nutrients and metals through a filter media.^ o Ultra-Drainguard: Ultra-Drainguard works by initially capturing sediment and trash and debris, and then combats dissolved oil, nutrients and metals through a filter media. The Ultra-Drainguard has an oil absorbent pillow that can be replaced separate from the filter during times of large free-oil mnoff. ^ • Basket-type Inlet Inserts o AbTech Ultra-Urban Filter: The Ultra-Urban Filter is a cost-effective BMP designed for use in storm drains that experience oil and grease pollution accompanied by sediment and trash and debris. The oil is permanently bonded to a SmartSponge, while sediment and trash and debris are captured in an internal basket. URL: http://www.epa.gov/regionl/assistance/ceitts/stormwater/techs/ wqtr paS doc - 13- o AquaGuard: AquaGuard works by initially capturing sediment and trash and debris, and then combats dissolved oil, nutrients and metals through a filter media. AquaGuard compares to others by being easy to handle, i.e. no special lifting equipment for filter removal.^ o FloGard: FloGard uses catch basin filtrafion, placing catch basin insert devices with a filter medium just under the grates of the stormwater system's catch basins. FloGard handles non-soluble solids such as sediment, gravel, and hydrocarbons, which are all potential pollutants originating from the roof and parking lot. FloGard is available for standard catch basins and for roof downspouts. Recommended Fillration System Option Sand, media, and bioretention filters require large amounts of land and have extremely high maintenance costs compared to proprietary filtration designs. Of the two types of filtration based inlet insert designs, experience within Southem California has shown the basket-type inlet inserts to be more reliable and less cumbersome for maintenance and proper operation.^ Therefore, the best type of filtration system for this project is one of the basket-type proprietary filtration based I inlet inserts. Hydrodvnamic Separator Systems Hydrodynamic separator systems (HDS) are flow-through stmctures with a settling or separation unit to remove sediments and other pollutants that are widely used in storm water treatment. No outside power source is required, because the energy of the flowing water allows the sediments to efficiently separate. Depending on the type of unit, this separation may be by means of swirl acfion or indirect filtration. " 2003 KriStar Enterprises. Inc. ^ Correspondence with the City of Dana Point, the City of Encinitas, and the City of Santa Monica \vqtr-pa8-doc - 14 - Hydrodynamic separator systems are most effective where the materials to be removed from mnoff are heavy particulates that can be settled or floatables that can be captured, rather than solids with poor settleability or dissolved pollutants. For hydrodynamic separator systems, there are four major proprietary types: • Continuous Deflective Separation (CDS): CDS provides the lowest cost overall when compared to other HDS units. A sorbent material can be added to remove unattached oil and grease.^ • Downstream Defender™: Downstream Defender traps sediment while intercepting oil and grease with a small head loss.^ • Stormceptor®: Stormceptor traps sediment while intercepting oil and grease.^ • Vortechs™: Vortechs combines baffle walls, circular grit chambers, flow control chambers, and an oil chamber to remove settleable solids and floatables from the storm water mnoff.^ Recommended Hydrodynamic Separalor System Option All of the abovementioned devices suffidentiy remove the pollutants of concem from this site. The best hydrodynamic separator for this project is the CDS unit; it has a relativdy low cost and has been widely used in San Diego County. BMP Sdecfion Basket-type proprietary filtration-based inlet inserts and CDS units are feasible options for this project. The recommended treatment BMP is a CDS Unit. The CDS Unit will be able to treat multiple planning areas in the Bressi Ranch Development, induding Planning Area 8. The CDS * CDS Technologies Inc 2002 '' 2003 Hydro International * Stormceptor 2003 ^ hltp://www.epa.gov/owm/mtb/hydro.pdf wqif paS.doc 15 - Unit will have lower maintenance frequency and costs than the inlet inserts due to the large number of inlets in the planning areas. BMP Plan Assumptions The following assumptions were made in calculating the required BMP sizes: • Flows generated on Leighton Lane will be treated, as well as storm water flows from the northern portion ofPlanning Area 11 (PA Ila). A mnoff coefficient, 'C value, of 0.55 was used in the mnoff calculafions for this tributary treatment area, since it is strictly residential and will average 50% impervious. • Flows generated onsite (majority of PA 8) will be treated, as well as storm water flows from Bressi Ranch Planning Areas 5, 7b, 9, 12, 13, 14 and 15b. A mnoff coefficient, 'C value, of 0.65 was used in the mnoff calculafions for this tributary treatment area. The treatment area includes industrial and residential areas; therefore the 'C value reflects the proportions of each for the BMP design. Table 5 summarizes the criteria that should be implemented in the design of the recommended 'project BMP. wqtr-pa8.doc 16- Table 5. BMP Design Criteria BMP Hydrology Treatment AreaA'^oIume Design Constraints • Locate outside public right-of-way C = 0.55 • Facilitate access for maintenance A = 25.7 acres • Avoid utility conflicts Flow-based: Q=CIA Qlreaiment— 2.8 CFS • Treatment Area/Volume from C= mnoff coefficient Leighton Lane & PA Ila A = acreage • Locate outside public right-of-way I = 0.2 in/hour C = 0.65 • Facilitate access for maintenance A = 144.8 acres • Avoid utility conflicts Qirealment= 18.8 CFS • Treatment Area//Vo]ume from PA 5,7b, 8,9, 12, 13, 14, & 15b Aqir paS.doc 17 5. PROJECT BMP PLAN IMPLEMENTATION This section identifies the recommended BMP options that meet the applicable storm water and water quality ordinance requirements. This includes incorporating BMPs to minimize and mitigate for mnoff contamination and volume from the site. The plan was developed per the proposed roadway and lot layout/density associated with the site. Construction BMPs During constmction, BMPs such as desilting basins, silt fences, sand bags, gravel bags, fiber rolls, and other erosion control measures may be employed consistent with the NPDES Storm Water Pollution Prevention Plan (SWPPP). The objectives ofthe SWPPP are to: • Identify all pollutant sources, including sources of sediment that may affect the water quality of storm water discharges associated with constmction activity from the constmction site; • Identify non-storm water discharges; • Identify, constmct, implement in accordance with a time schedule, and maintain BMPs to reduce or eliminate pollutants in storm water discharges and authorized non-storm water discharges from the constraction site during constmction; and • Develop a maintenance schedule for BMPs installed during constraction designed to reduce or eliminate pollutants after constraction is completed (post-constmction BMPs). Recommended Post-Construction BMP Plan PDC has identified a recommended water quality BMP plan for the Bressi Ranch Residential Planning Area 8 Project. The following BMP plan is preliminary and is subject to change pending City review and implementation of future policy requirements, and final engineering design. wqir paS doc ne recommended post-construction BMP plan includes site design, source control, and treatment BMPs. The site design and source control BMPs include protection of slopes and channels, inlet stenciling and signage, covered trash storage, efficient irrigation, storm water education, and integrated pest manageinent principles. The treatment BMP selected for this project is a CDS Unit. TABLE 6. POST-CONSTRUCTION BMP SUMMARY Pollutant Pollutant Sources Mitigation Measures Sediment and attached pollutants (nutrients, peslicides. tieavy melals) Landscaping, driveways, rooftops Inlet stenciling and signage, education of residents, CDS Unit Trash and debris Littering, trash storage areas, swimming pool deck, rooftop Inlet stenciling and signage, covered trash storage, education of residents, CDS Unit Bacteria and virases Trash storage areas, pets Covered trash storage, education of residents ^ Oxygen demanding substances Landscaping, driveways and roadways Inlet stenciling and signage, regular City of San Diego yard waste pickup, education of residents, detention basin, CDS Unit Oil and grease Driveways, roadways Inlet stenciling and signage, education of residents, CDS Unit Operation and Maintenance Plans The City Storm Water Standards require a description of the long-term maintenance requirements of proposed BMPs and a description of the mechanism that will ensure ongoing long-term maintenance. Operation and maintenance plans for the recommended post- constraction BMP for this project are located in Appendix 4. The Project BMP costs and the maintenance funding sources are provided in the following section. .\ qtr- pa 8 doc - 19 6. PROJECT BMP COSTS AND FUNDING SOURCES Table 7 below provides the anticipated capital and annual maintenance costs for the CDS Unit. TABLE?. BMP COSTS BMP OPTION 1. Single CDS Unit Modd PMSU 70 70 Equipment Cost $64,900=* Installation Cost $55,900 Annual Maintenance Cost $1,000 *CDS Units are a proprietary BMP and may vary in cost at the manufacturer's discretion. The developer will incur the capital cost for the BMP installation. The responsible party for long-term maintenance and funding is the Home Owners' Assodation (HOA) for Bressi Ranch. wqir-paS doc -20- APPENDIX 1 Storm Water Requirements Applicability Checklist storm Water Standards 4/03/03 VI. RESOURCES & REFERENCE^*^- ' ^ * 1, rAPPENDIX A STORM WATER REQUIREMENTS APPLICABILITY CHECKLIST Complete Sections 1 and 2 of the following checklist to determine your project's permanent and construction storm water best management practices requirements. This form must be completed and submitted with your permit application. Section 1. Permanent Storm Water BMP Requirements: If any answers to Part A are answered "Yes," your project is subject to the "Priority Project Permanent Storm Water BMP Requirements," and "Standard Permanent Storm Water BMP Requirements" in Section III, "Permanent Storm Water BMP Selection Procedure" in the Sform Waler Standards manual. If all answers to Part A are "No," and any answers to Part B are "Yes," your project is only subject to the "Standard Permanent Storm Water BMP Requirements". If every question in Part A and B is answered "No," your project is exempt from permanent storm water requirements. Part A: Determine Priority Project Permanent Storm Water BMP Requirements. Does the project meet the definition of one or more of the priority project categories?* Yes No 1. Detached residential development of 10 or more units 2. Attached residential development of 10 or more units 3. Commercial development greater than 100,000 square feet 4. Automotive repair shop 5. Restaurant 6. Steep hillside development greater than 5,000 square feet 7. Project discharging to receiving waters within Environmentally Sensitive Areas Parking lots greater than or equal to 5,000 fr or with at least 15 parking spaces, and potentially exposed to urban runoff 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 Wafer Standards for expanded definitions of the priority project categories. Limited Exclusion: Trenching and resurfacing work associated with utility projects are not considered priority projects. Parking lots, buildings and other structures associated with utility projects are priority projects if one or more of the criteria in Part A is met. If all answers to Part A are "No", continue to Part B. 30 Storm Water Standards 4/03/03 Part B: Determine Standard Permanent Storm Water Requirements Does the project propose: Yes No 1. New impervious areas, such as rooftops, roads, parking lots, driveways, paths and sidewalks? 2. New pervious landscape areas and irrigation systems? 3. Permanent structures within 100 feet of any natural water body? 4. Trash storage areas? V 5. Liquid or soiid material loading and unloading areas? 6. Vehicle or equipment fueling, washing, or maintenance areas? 7. Require a General NPDES Permit for Storm Water Discharges Associated with Industrial Activities (Except construction)?* 8. Commercial or industrial waste handling or storage, excluding typical office or household waste? 9. Any grading or ground disturbance during construction? 10. Any new storm drains, or alteration to existing storm drains? *To find out if your project is required to obtain an individual General NPDES Permit for Storm Water Discharges Associated with Industrial Activities, visit the State Water Resources Control Board web site at, www.swrcb.ca.gov/stormwtr/industrial.html Section 2. Construction Storm Water BMP Requirements: If the answer to question 1 of Part C is answered "Yes," your project is subject to Section IV, "Construction Storm Water BMP Performance Standards," and must prepare a Storm Water Pollution Prevention Plan (SWPPP). If the answer to question 1 is "No," but the answer to any of the remaining questions is "Yes," your project is subject to Section IV, "Construction Storm Water BMP Performance Standards," and must prepare a Water Pollution Control Plan (WPCP). If every question in Part C is answered "No," our project is exempt from any construction storm water BMP requirements. If any of he answers to the questions in Part C are "Yes," complete the construction site prioritization in Part D, below. Part C: Determine Construction Phase Storm Water Requirements. Would the project meet any of these criteria during construction? Yes No 1. Is the project subject to California's statewide General NPDES Permit for Storm Water Discharges Associated With Construction Activities? \/ 2. Does the project propose grading or soil disturbance? y 3. Would storm water or urban runoff have the potential to contact any portion of the construction area, including washing and staging areas? 4. Would the project use any construction materials that could negatively affect water quality if discharged from the site (such as, paints, solvents, concrete, and stucco)? / 31 t>torm water Standards 4/03/03 Part D: Determine Construction Site Priority In accordance with the Municipal Permit, each construction site with construction storm water BMP requirements must be designated with a priority: high, medium or low. ' This prioritization must be completed with this form, noted on the plans, and included in the SWPPP or WPCP. Indicate the project's priority in one of the check boxes using the criteria below, and existing and surrounding conditions of the project, the type of activities 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.] A) Higii Priority 1) Projects where the site is 50 acres or more and grading will occur during the rainy season 2) Projects 5 acres or more. 3) Projects 5 acres or more within or directly adjacent to or discharging directly to a coastal lagoon or other receiving water within an environmentally sensitive area Projects, active or inactive, adjacent or tributary to sensitive water bodies Q B) Med/t/m Priority 1) Capital Improvement Projects where grading occurs, however a Storm Water Pollution Prevention Plan (SWPPP) is not required under the State General Construction Permit (i.e., water and sewer replacement projects, intersection and street re-alignments, widening, comfort stations, etc.) 2) Permit projects in the public right-of-way where grading occurs, such as installation of sidewalk, substantial retaining walls, curb and gutter for an entire street frontage, etc. , however SWPPPs are not required. 3) Permit projects on private property where grading permits are required, however, Notice Of Intents (NOIs) and SWPPPs are not required. • C) Low Priority 1) Capital Projects where minimal to no grading occurs, such as signal light and loop installations, street light installations, etc. 2) Permit projects in the public right-of-way where minimal to no grading occurs, such as pedestrian ramps, driveway additions, small retaining walls, etc. 3) Permit projects on private property where grading permits are not required, such as small retaining walls, single-family homes, small tenant improvements, etc. 32 APPENDIX 2 Project Maps VICINITY MAP NOT TO SCALE