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SDP 14-01; Burke Carlsbad Business Center; Site Development Plan (SDP) (4)
STORM WATER MANAGEMENT PLAN FOR L0T17 CARLSBAD RACEWAY BUSINESS PARK PLANNED INDUSTRIAL PERMIT September 4, 2013 Prepared For: Burke Real Estate Group Prepared By: O'DAY CONSULTANTS, INC. 2710 Loker Avenue West, Suite 100 Carlsbad, CA 92010 J.N. 13-1020-03 RECEIVED JAN 0 6 im CITY OF CARLSBAD PLANNING DIVISION Lot 17 - Carlsbad Raceway Business Park SWMP TABLE OF CONTENTS TABLE OF CONTENTS i ATTACHMENTS: ii 1. PROJECT SETTING 1 2. APPLICABLE STORMWATER STANDARDS 3 2a. Storm Water Standards Questionnaire 3 2b. HMP Apphcability Determination 3 3. IDENTIFY POLLUTANTS OF CONCERN 4 3a. Identify pollutants associated with type of project/use 4 3b. Identify watershed, hydrologic unit basin and receiving waters 4 3c. List impaired water bodies 5 3d. Beneficial uses of receiving water 5 3e. Summarize primary pollutants of concern 6 4. SOURCE CONTROL MEASURES 8 4a. Description of site activities and potential sources of pollutants 8 4b. Stormwater Pollutant Sources and Source Controls 8 5. LOW IMPACT DEVELOPMENT (LID) DESIGN STRATEGIES 11 6. INTEGRATED MANAGEMENT PRACTICES (IMP's) 12 6a. Selection process for IMP's 12 6b. Sizing factors for IMP's 12 6c. Geotechnical recommendation on soil infiltration rates 12 6d. Infiltration calculations 12 7. TREATMENT CONTROL BMP's 13 8. HYDROMODIFICATION 14 8a. Lower Flow Threshold Determination 14 8b. Continuous Simulation Model 15 8c. Tabulation of Flow-control Facility Sizes and Design Criteria 15 9. DOCUMENTATION OF STORMWATER DESIGN 16 9a. Hydrology maps 16 9b. BMP Sizing Calculator 16 10. BMP FACILITY MAINTENANCE REQUIREMENTS 17 10a. Ownership and responsibility of maintenance of BMP's 17 10b. Summary of maintenance requirements 17 11. SWMP CERTIFICATION STATEMENTS 18 Lot 17 - Carlsbad Raceway Business Park ATTACHMENTS: 1. Storm Water Standards Questionnaire 2. BMP and DMA Plan Exhibit 3. SWMM Program Results 4. Urban Green®Biofiltration Specifications and Details 5. Bioretention Basin Specifications and Details per Planned Industrial Permit I:\131020\Stormwaier Site\SWMPM 31020-SWMP.doc Lot 17 - Carlsbad Raceway Business Park SWMP 1. PROJECT SETTING Lot 17 of Carlsbad Raceway Business Park project is located north of Lionshead Avenue and east of Melrose Drive in the City of Carlsbad, California (see Vicinity Map below). The entire site is approximately 4.8 acres. Lot 17 is currently an existing mass graded lot per approved grading plan Drawing 409-lA. The purpose of this preliminary SWMP is to support a Planned Industrial Permit "PIP" which proposes the development of the site for industrial use. The site will include approximately 76,326 S.F. of building permit area (includes truck docks and trash enclosures) and approximately 177 parking spaces. The remainder of the site will be landscaping. CITY OF _ OCWMSIDE HIGHWAY, SITE BUSINESS PARK DR. OF MARCOS CITY OF ENCINITAS VICINITY MAP SCALE I;\13l020\Stonnwater Site\SWMP\131020-SWMP.doc Lot 17 - Carlsbad Raceway Business Park The existing site drains towards the northeasterly corner into a desilting basin that drains to an existing 54-inch storm drain that traverses the project in a south to northerly direction The County of San Diego Hydrology Manual Soil Hydrologic Group identifies Soil Group D as the predominant soil type Hydrologic Soils Group D soils have a very slow infiltration rate (high runoff potential) when thoroughly wet. These soils have a very slow rate of water transmission. The proposed land use is Commercial use. Typical activities that could affect storm water include: Loading docks; landscape maintenance; pest control; hazardous material use; refuse services; storage; fire sprinkler testing; and miscellaneous wash water. Stormwater control and treatment constraints include: poor soil type and permeability (soil type D); high intensity land use; steep terrain; heavy pedestrian or vehicular traffic; restricted right-of-way; and safety concerns. Opportunities include landscape buffer areas and elevation differences. Under existing conditions, there is a single location where runoff from the lot discharges to as indicated on City of Carlsbad Grading Plans Drawing No. 409-lA, sheet 14 and Drawing No. 409-1, sheet 23. Runoff from the site drains to an existing desilting basin that is connected to a 54-inch storm drain that traverses the site and then discharges into an existing downstream detention basin west of Lot 17. The 54-inch storm drain is part of the existing drainage infrastructure serving the surrounding Carlsbad Raceway Business Park. The controlled discharge from the downstream detention basin eventually discharges to Agua Hedionda Creek, which ultimately flows into Agua Hedionda Lagoon and finally the Pacific Ocean. Under proposed conditions, the majority of the site drains toward the northeasterly corner of the site (Point of Compliance No. 1) . The remaining portion of the site will drain towards the south, near Lionshead Avenue (Point of Compliance No. 2). Treatment and flow controls will be done on all site drainage prior to entering the City's storm drain system. Discharge points to the City's MS4 remain unchanged. l:\131020\Stonnwater Site\SWMP\131020-SWMP.doc Lot 17 - Carlsbad Raceway Business Park SWMP 2. APPUCABLE STORMWATER STANDARDS 2a. Storm Water Standards Questionnaire Results of the completed City of Carlsbad Storm Water Standards Questionnaire (SWSQ) indicate this project to be a Priority Development Project (PDP) and therefore must comply with additional stormwater criteria per the SUSMP. (See Attachment 1 for completed SWSQ) 2b. HMP Applicability Determination According to Figure 2-1, HMP Applicability determination flowchart below, Hydromodification controls are required. It was determined that field investigations would not be conducted pursuant to the SCCWRP channel screening tools. Therefore the site must mitigate peak flows and durations based on a pre-project condition lower flow threshold of 0.1Q2. FIGURE 2-1. HMP Applicability Determination I,\131020\Stor!nwaler Site\SWMP\131020-SWMP.doc Lot 17 - Carlsbad Raceway Business Park SWMP 3. IDENTIFY POLLUTANTS OF CONCERN 3a. Identify pollutants associated with type of project/use Table 2-1 of the SUSMP (see below) identifies the pollutants anticipated from the Lot 17 commercial development and associated improvements as indicated by the shaded categories. TABLE 2-1. ANTICIPATED AND POTENTIAL PoUutants Generated by Land Use Type. General PoUutant Categories Priority Project Catejipries Sediment Nutrients Heavy Metals Organic Compounds Trash & Debris Oxygen Demanding Substances OU& Grease Bacteria & Viruses Pesticides Detached Residential Development X X X X X X X Attached Residential Development X X X P(l) P(2) P X C '.ommenial Development >one acre Pin I'd) X P(2) X \\5) X P(3) P(5) Heavy Industry X X X X X X Automotive Repair Shops X X(4)(5) X X Restaurants X X X X P(l) I lillside Development >5,000 ft2 X X X X X X Parking Lots P(l) P(l) X X P(l) X P(l) Retail Gasoline Outlets X X X X X .Streets, 1 lighways & Freeways X P(l) X X(4) X P(5) X X P(l) 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. 3b. Identify watershed, hydrologic unit basin and receiving waters The project is located in the Agua Hedionda Hydrologic Subarea (904.31) ofthe Carlsbad Hydrologic Unit in the San Diego Region All site drainage from Lot 17 enters the City of Carlsbad's MS4 at two separate locations along storm drain traversing the site. Flows from the site confluences with flows from surrounding developments before being conveyed northwesterly to an existing downstream detention basin located west of Melrose Drive. It then enters Agua Hedionda Creek approximately 1.5 miles downstream, and Agua Hedionda Lagoon about 3.0 miles further downstream. I:\131020\Slormwater Site\SWMP\l31020-SWMP.doc Lot 17 - Carlsbad Raceway Business Park 3c. List impaired water bodies According to the California 2006 303(d) list of Water Quality limited Segments published by the RWQCB, there are currently no TMDLs established for Agua Hedionda Lagoon or Agua Hedionda Creek. Agua Hedionda Lagoon is impaired by indicator bacteria and sedimentation/siltation. Agua Hedionda Creek is listed as Impaired with Manganese, selenium, sulfates and total dissolved solids. 3d. Beneficial uses of receiving water The beneficial uses for the hydrologic unit are indicated in Table 2-2 and 2-3 and described in detail below. This information comes from the Water Quality Control Plan for the San Diego Basin. Table 2-2. BENEFICIAL USES OF INLAND SURFACE WATERS BENEFICIAL USE In land Surface Waters Hydrologic Unit Basin M U N A fl 1 N D P R G W R F R P 0 W R E R E B 1 w A C 0 W 1 R A S P Number M U N o D 1 N D 0 G W R S P 0 W C C 0 R L L R w M U N r\ 1 N D C G W R H P 0 W 1 2 L M D D E N Agua Hedionda Watershed Agua Hedionda Lagoon 4.31 See Coast Water -Table 2-3 Agua Hedionda Creek 4.31 • • • • • • • + Excepted from MUN • Existing Beneficial Use Waterbodies are listed multiple times if they cross hydrologic area or sub area boundaries. Beiielif IISI; designations ap|)ly to all liibiitaries to tlie iiulualed waterbody, if not listed separately. Table 2-3. BENEFICIAL USES OF COASTAL WATERS BENEFICIAL USE Coastal Waters Hydrologic Unit Basin Number w M Batiquitos Lagoon Beneficial Uses of Inland Surface Waters MUN - Municipal and Domestic Supply: Includes uses of water for community, military, or individual water supply systems including, but not limited to, drinking water supply. AGR - Aquaculture: Includes the uses of water for aquaculture or mariculture operations including, but not limited to, propagation, cultivation, maintenance, or harvesting of aquatic plants and animals for human consumption or bait purposes. REC 1 -Contact Recreation: Includes uses of water for recreational activities involving body contact with water, where ingestion of water is reasonably possible. These uses include, but are not limited to, swimming, wading, water-skiing, skin and SCUBA diving, surfing, white water activities, fishing, or use of natural hot springs. REC 2 -Non-Contact Recreation: Includes the uses of water for recreational activities involving proximity to water, but not normally involving body contact with water, where ingestion of water is reasonably possible. These include, but are not limited to, picnicking, sunbathing, hiking, beachcombing, camping, boating, tide pool and marine life study, hunting, sightseeing, or aesthetic enjoyment in conjunction with the above activities. I:\131020\Stormwaler Sile\SWMP\ 131020-SV/MP.doc Lot 17 - Carlsbad Raceway Business Park 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, vegetation, wildlife, (e.g., mammals, birds, reptiles, amphibians, invertebrates), or wildlife water food and sources. Beneficial Uses of Coastal Waters REC 1 - See Beneficial Uses of Inland Surface Waters above REC 2 - See Beneficial Uses of Inland Surface Waters above BIOL - Preservation of Biological Habitats of Special Significance: Includes uses of water that support designated areas or habitats, such as established refuges, parks, sanctuaries, ecological reserves, or Areas of Special Biological Significance (ASBS), where the preservation or enhancement of natural resources requires special protection. EST - Estuarine Habitat: Includes the uses of water that support estuarine ecosystems including, but not limited to, preservation or enhancement of estuarine habitats, vegetation, fish, or wildlife (e.g., estuarine mammals, waterfowl, shorebirds). WILD - See Beneficial Uses of Inland Surface Waters above RARE - Rare, Threatened, or Endangered Species: Includes uses of water that support habitats necessary, at least in part, for the survival and successful maintenance of plant or animal species established under state or federal law as rare, threatened or endangered. MAR -Marine Habitat: Includes uses of water that support marine ecosystems including, but not limited to, preservation or enhancement or marine habitats, vegetation such as kelp, fish, shellfish, or wildlife (e.g., marine mammals, shorebirds). MIGR -Migration of Aquatic Organisms: Includes uses of water that support habitats necessary for migration, acclimatization between fresh and salt water, or other temporary activities by aquatic organisms, such as anadromous fish. SPWN - Spawning, Reproduction, and/or Early Development: Includes uses of water that support high quality aquatic habitats suitable for reproduction and early development offish. This use is applicable only for the protection of anadromous fish. 3e. Summarize primary pollutants of concern The primary pollutants of concern for this project are sediment, nutrients, heavy metals, organic compounds, trash & debris, oxygen demanding substances, oil & grease, bacteria & viruses, and pesticides. The extensive use of bioretention treatment control facilities throughout the site should be a I:\I31020\Slormwaler Site^SV^-MPM31020-SWMP.doc Lot 17 - Carlsbad Raceway Business Park highly effective method of treating coarse sediment and trash, and pollutants that tend to associate with fine particles during treatment. Bioretention facilities also show medium effectiveness for treatment of pollutants that tend to be dissolved following treatment. 31020\Storniwaler Site\SWMP\l31020-SWMP.doc Lot 17 - Carlsbad Raceway Business Park SWMP 4. SOURCE CONTROL MEASURES 4a. Description of site activities and potential sources of pollutants Activities and potential pollutant sources associated with this site include: 4b. On-site storm drain inlets Interior floor drains Landscape and outdoor pesticide use Refuse areas Loading docks Fire sprinkler test water Miscellaneous drain or wash water consisting of: o Boiler drain lines o Condensate drain lines o Rooftop equipment o Drainage sumps o Roofing, gutters, and trim Plazas, sidewalks, and parking lots Stormwater Pollutant Sources and Source Controls The following table identifies permanent and operational source control measures for the project site as outlined in Appendix 1, Stormwater Pollutant Sources and Source Control checklist in the City's SUSMP: Potential Source of Runoff Pollutants Permanent Source Control BMPs Operational Source Control BMPs On-Site Storm Drain Inlets Mark all inlets with the words "No Dumping! Flows to Bay" or similar. Maintain and periodically repaint or replace inlet markings. Provide stormwater pollution prevention information to site owners, lessees, or operators. See applicable operational BMPs in Fact Sheet SC-44, "Drainage System Maintenance," in the CASQA Stormwater Quality Handbooks at www.cabmphandbooks.com Include the following in lease agreements: "Tenant shall not allow anyone to discharge anything to storm drains or to store or deposit materials so as to create a potential discharge to storm drains." Provide stormwater pollution prevention information to site owners, lessees, or operators. Landscape and Outdoor Pesticide Use Final landscape plans will accomplish all ofthe following: • Preserve existing native trees, shrubs, and ground Maintain landscaping using minimum or no pesticides. 8 I:\131020\Stormwater Site\SWMP\ 131020-SWMP.doc Lot 17 - Carlsbad Raceway Business Park Potential Source of Runoff Pollutants Permanent Source Control BMPs Operational Source Control BMPs cover to the maximum extent possible. • Design landscaping to minimize irrigation and runoff, to promote surface infiltration where appropriate, and to minimize the use of fertilizers and pesticides that can contribute to stormwater pollution. • where landscaped areas are used to retain or detain stormwater, specify plants that are tolerant of saturated soil conditions. • Consider using pest-resistant plants, especially adjacent to hardscape. • To insure successful establishment, select plants appropriate to site soils, slopes, climate, sun, wind, rain, land use, air movement, ecological consistency, and plant interactions. • See applicable operational BMPs in Fact Sheet SC-41, "Building and Grounds Maintenance," in the CASQA Stormwater Quality Handbooks at www.cabmphandbooks.com • Provide IPM information to new owners, lessees and operators. Refuse Areas State that signs will be posted on or near dumpsters with the words "Do not dump hazardous materials here" or similar. Provide adequate number of receptacles. Inspect receptacles regularly; repair or replace leaky receptacles. Keep receptacles covered. Prohibit/prevent dumping of liquid or hazardous wastes. Post "no hazardous materials" signs. Inspect and pick up litter daily and clean up spills immediately. Keep spill control materials available on-site. See Fact Sheet SC-34, "Waste Handling and Disposal" in the CASQA Stormwater Quality Handbooks at www.cabmphandbooks.com Outdoor storage of Equipment or Materials. • Include a detailed description of materials to be stored, storage areas, and structural features to prevent pollutants from entering storm drains. Where appropriate, reference documentation and compliance with the requirements of local Hazardous Materials Programs for: • Hazardous Waste Generation • Hazardous Materials Release Response and Inventory • California Accidental Release (CalARP) • Aboveground Storage Tank • Uniform Fire Code Article 80 Section 103(b) & (c) 1991 • Underground Storage Tank See the Fact Sheets SC-31, "Outdoor Liquid Container Storage" and SC-33, "Outdoor storage of Raw Materials " in the CASQA Stormwater Quality Handbooks at www.cabmphandbooks.com Loading Docks Bio-clean trench drain insert to be installed in each loading dock trench drain. Move loaded and unloaded items indoors as soon as possible. I:\131020\Stormwater Site\SWMP\ 131020-SWMP.doc Lot 17 - Carlsbad Raceway Business Park Potential Source of Runoff Pollutants Permanent Source Control BMPs Operational Source Control BMPs • See Fact Sheet SC-30, "Outdoor Loading and Unloading," in the CASQA Stormwater Quality Handbooks at www.cabmphandbooks.com Fire Sprinkler Test Water • Obtain a permit from the Leucadia Wastewater District to provide a means to drain fire sprinkler test water to the sanitary sewer. • See the note in Fact Sheet SC-41, "Building and Grounds Maintenance," in the CASQA Stormwater Quality Handbooks at www.cabmDhandbooks.com Miscellaneous Drain or Wash Water: • Boiler drain lines • Condensate drain lines • Rooftop equipment • Boiler drain lines shall be directly or indirectly connected to the sanitary sewer system and may not discharge to the storm drain system. • Condensate drain lines may discharge to landscaped areas if the flow is small enough that runoff will not occur. Condensate drain lines may not discharge to the storm drain system. • Drainage sumps • Roofing, gutters, and trim • Rooftop mounted equipment with potential to produce pollutants shall be roofed and/or have secondary containment. • Any drainage sumps on-site shall feature a sediment sump to reduce the quantity of sediment in pumped water. • Avoid roofing, gutters, and trim made of copper or other unprotected metals that may leach into runoff. Sidewalk and Parking Lots • Sidewalks and parking lots shall be swept regularly to prevent the accumulation of litter and debris. Debris from pressure washing shall be collected to prevent entry into the storm drain system. Wash water containing any cleaning agent or degreaser shall be collected and discharged to the sanitary sewer and not discharged to a storm drain. 10 I:\131020\Stormwater Sile\SWMP\131020-SWMP.doc Lot 17 - Carlsbad Raceway Business Park SWMP 5. LOW IMPACT DEVELOPMENT (LID) DESIGN STRATEGIES The LID strategies applicable to this commercial development project include dispersing runoff to adjacent pervious surfaces and draining to Integrated Management Practices (IMPs). The entire site has been divided into four drainage areas comprising of discrete Drainage Management Areas (DMAs) based on surface type. These areas were used to determine which LID strategy alternative best applies to that specific drainage area. The Integrated Management Practice (IMP) approach was used on four DMAs to meet both treatment and/or hydromodification flow control objectives. See Section 8 for further hydromodification design. Attachment 2, BMP and DMA Exhibit, depicts each of these strategies and locations of treatment, hydromodification and flow-control facilities. 11 l;\131020\Stormwater Site\SWMP\131020-SWMP.doc Lot 17 - Carlsbad Raceway Business Park SWMP 6. INTEGRATED MANAGEMENT PRACTICES (IMP's) 6a. Selection process for IMP's According to Table 2-2 of the SUSMP, the majority of pollutants of concern for this project can be grouped in the category of pollutants that tend to associate with fine particles during treatment. Nutrients also fall under the category of pollutants that tend to be dissolved following treatment and trash & debris falls under the category of coarse sediment and trash. According to Table 2-3,infiltration facilities provide the highest effectiveness for removal of pollutants in all three categories but our site is constrained by impermeable soils. Bioretention facilities were chosen extensively throughout the site for their high removal rates of coarse sediment and trash and pollutants that tend to associate with fine particles during treatment and their medium removal rates for Pollutants that tend to be dissolved following treatment. Bioretention facilities detain stormwater and filter it slowly through engineered soil or sand and are versatile in that they can be any shape and can be landscaped. The bioretention areas onsite were sized to treat stormwater and/or limit flow using control through hydromodification. 6b. Sizing factors for IMP'S 1) Threshold Determination The downstream receiving water channel was not assessed, therefore, according to Figure 2-2 of the City's SUSMP, the site must mitigate peak flows and durations based on a pre-project condition lower flow threshold of 0.1Q2. 2) HMP Decision Matrix IMP facilities were sized using the Decision Matrices in Figures 2-2 in Section 8, hydromodification. 6c. Geotechnical recommendation on soil infiltration rates IMP facilities were chosen that do not drain through native soil, as soil infiltration rates were anticipated to be low. 6d. Infiltration calculations Self-retaining areas were not utilized on this site, as soil infiltration rates were anticipated to be low. 12 :\131020\Slormwater Site\SWMP\l31020-SWMP.doc Lot 17 - Carlsbad Raceway Business Park SWMP 7. TREATMENT CONTROL BMP's Water quality treatment will be accomplished through the use of bioretention facilities and Urban Green® units. Bioretention basin areas were sized for both treatment and hydromodification. See PIP for details and specifications for bioretention basins (Attachment 5). Urban Green® details and specifications are in Attachment 4. 13 :\131020\Stormwaler Site\SWMP\l31020-SWMP.doc Lot 17 - Carlsbad Raceway Business Park SWMP 8. HYDROMODIFICATION 8a. Threshold Determination Field investigations were not conducted pursuant to SCCWRP screening tools. Therefore, according to Figure 2-2 below, the site must mitigate peak flows and durations based on a pre- project condition lower flow threshold of 0.1Q2. Consult with Geotechnical Engineer Redesign LID or BMP FIGURE 2-2. Mitigation Criteria and Implementation 14 I :\131020\Stonnwaler Site\S WM P\ 131020-S WM P.doc Lot 17 - Carlsbad Raceway Business Park 8b. Continuous Simulation Model A continuous simulation model (Storm Water Management Mode - SWMM) is being utilized to simulate runoff quantity and quality from Lot 17. 8c. Tabulation of Flow-control Facility Sizes and Design Criteria The Storm Water Management Model (SWMM) program hydrology and conveyance system hydraulics software was used to simulation single event or long-term (continuous) simulation of runoff quantity and quality from primarily urban areas. See Attachment 3 for SWMM report results. See PIP for details and specifications for bioretention basins. 15 I:\131020\Stormwater Site\SWMP\131020-SWMP.doc Lot 17 - Carlsbad Raceway Business Park SWMP 9. DOCUMENTATION OF STORMWATER DESIGN 9a. Hydrology maps Attachment 2, BMP and DMA Plan Exhibit, depicts the treatment controls, low impact design, source control BMPs, and boundaries of each drainage area draining to each IMP. 9b. SWMM LID BMP Sizing Attachment 3 includes the SWMM Results for each IMP considered. The report calculates the plan area, ponding volume, storage volume, and orifice flow and size for each IMP considered. 16 : :\131020\Storinwater Site\S WM P\ 131020-S WM P.doc Lot 17 - Carlsbad Raceway Business Park SWMP 10. BMP FACILITY MAINTENANCE REQUIREMENTS 10a. Ownership and responsibility of maintenance of BMP's The Owner and Developer will be responsible for the maintenance of treatment facilities. Ongoing maintenance will be assured by executing a Permanent Stormwater Quality BMP Maintenance Agreement that "runs with the land." 10b. Summary of maintenance requirements Bioretention facilities remove pollutants primarily by filtering runoff slowly through aerobic, biologically active soil. Routine maintenance is needed to ensure that flow is unobstructed, that erosion is prevented, and that soils are held together by plant roots and are biologically active. Typical maintenance consists ofthe following: • Inspect inlets for channels, exposure of soils, or other evidence of erosion. Clear any obstructions and remove any accumulation of sediment. Examine rock or other material used as a splash pad and replenish if necessary. • Inspect outlets for erosion or plugging. • Inspect side slopes for evidence of instability or erosion and correct as necessary. • Observe the surface of bioretention facility soil for uniform percolation throughout. If portions of the bioretention facility do not drain within 24 hours after the end of a storm, the soil should be tilled and replanted. Remove any debris or accumulations of sediment. • Confirm that check dams and flow spreaders are in place and level and that rivulets and channelization are effectively prevented. • Examine the vegetation to ensure that it is healthy and dense enough to provide filtering and to protect soils from erosion. Replenish mulch as necessary, remove fallen leaves and debris, prune large shrubs or trees, and mow turf areas. When mowing, remove no more than 1/3 height of grasses. Confirm that irrigation is adequate and not excessive and that sprays do not directly enter overflow grates. Replace dead plants and remove noxious and invasive vegetation. • Abate any potential vectors by filling holes in the ground in and around the bioretention facility and by insuring that there are no areas where water stands longer than 48 hours following a storm. If mosquito larvae are present and persistent, contact the San Diego County Vector Control Program for information and advice. Mosquito larvicides should be applied only when absolutely necessary and then only by a licensed individual or contractor. 17 l:\131020\Stormwaler Site\SWMPU31020-SWMP.doc Lot 17 - Carlsbad Raceway Business Park SWMP 11. SWMP CERTIFICATION STATEMENTS 11a. Preparer's statement The selection, sizing, and preliminary design of stormwater treatment and other control measures in this plan meet the requirements of Regional Quality Control Board Order R9-2007-0001 and subsequent amendments. NAME DATE lib. Owner's statement The selection, sizing, and preliminary design of stormwater treatment and other control measures in this plan meet the requirements of Regional Quality Control Board Order R9-2007-0001 and subsequent amendments. NAME DATE 18 I:\131020\Stormwater Site\S WM P\ 131020-S WM P.doc ATTACHMENT 1 STORMWATER STANDARDS QUESTIONNAIRE ^ CITY CARLSBAD O F STORM WATER STANDARDS QUESTIONNAIRE E-34 Development Services Land Development Engineering 1635 Faraday Avenue 760-602-2750 www.carlsbadca.gov INSTRUCTIONS: To address post-development pollutants that may be generated from development projects, the City requires that new development and significant redevelopment priority projects incorporate Permanent Storm Water Best Management Practices (BMP's) into the project design per the City's Standard Urban Stormwater Management Plan (SUSMP). To view the SUSMP, refer to the Engineering Standards (Volume 4, Chapter 2) at www.carlsbadca.qov/standards. Initially this questionnaire must be completed by the applicant in advance of submitting for a development application (subdivision, discretionary permits and/or construction permits). The results of the questionnaire determine the level of storm water standards that must be applied to a proposed development or redevelopment project. Depending on the outcome, your project will either be subject to Standard Stormwater Requirements' or be subject to additional criteria called 'Priority Development Project Requirements'. Many aspects of project site design are dependent upon the storm water standards applied to a project. Your responses to the questionnaire represent an initial assessment of the proposed project conditions and impacts. City staff has responsibility for making the final assessment after submission of the development application. If staff determines that the questionnaire was incorrectly filled out and is subject to more stringent storm water standards than initially assessed by you, this will result in the return of the development application as incomplete. In this case, please make the changes to the questionnaire and resubmit to the City. If you are unsure about the meaning of a question or need help in determining how to respond to one or more of the questions, please seek assistance from Land Development Engineering staff. A separate completed and signed questionnaire must be submitted for each new development application submission. Only one completed and signed questionnaire is required when multiple development applications for the same project are submitted concurrently. In addition to this questionnaire, you must also complete, sign and submit a Project Threat Assessment Form with construction permits for the project. Please start by completing Step 1 and follow the instructions. When completed, sign the form at the end and submit this with your application to the city. STEP1 TO BE COMPLETED FOR ALL PROJECTS To determine if your project is a priority development project, please answer the following questions: YES NO 1. Is your project LIMITED TO constructing new or retrofitting paved sidewalks, bicycle lanes or trails that meet the following criteria: (1) Designed and constructed to direct storm water runoff to adjacent vegetated areas, or other non-erodible permeable areas; OR (2) designed and constructed to be hydraulically disconnected from paved streets or roads; OR (3) designed and constructed with permeable pavements or surfaces in accordance with USEPA Green Streets guidance? X 2. Is your project LIMITED TO retrofitting or redeveloping existing paved alleys, streets, or roads that are designed and constructed in accordance with the USEPA Green Streets guidance? X If you answered "yes" to one or more of the above questions, then your project is NOT a priority development project and therefore is NOT subject to the storm water criteria required for priority development projects. Go to step 4, mark the last box stating "my project does not meet PDP requirements" and complete applicant information. If you answered "no" to both questions, then go to Step 2. E-34 Page 1 of 3 Effective 6/27/13 <^l>> CITY OF STORM WATER <^l>> CITY OF STANDARDS Development Services Land Development Engineering <^l>> CITY OF QUESTIONNAIRE E-34 1635 Faraday Avenue 760-602-2750 CARLSBAD QUESTIONNAIRE E-34 www.carlsbadca.gov STEP 2 TO BE COMPLETED FOR ALL NEW OR REDEVELOPMENT PROJECTS To determine if your project is a priority development project, please answer the following questions: YES NO 1. Is your project a new development that creates 10,000 square feet or more of impervious surfaces collectively over the entire project site? This includes commercial, industrial, residential, mixed-use, and public development projects on public or private land. X 2. Is your project creating or replacing 5,000 square feet or more of impervious surface collectively over the entire project site on an existing site of 10,000 square feet or more of impervious surface? 777/s includes commercial, industrial, residential, mixed-use, and public development projects on public or private land. 3. Is your project a new or redevelopment project that creates 5,000 square feet or more of impervious surface collectively over the entire project site and supports a restaurant? A restaurant is a facility that sells prepared foods and drinks for consumption, including stationary lunch counters and refreshment stands selling prepared foods and drinks for immediate consumption. 4. Is your project a new or redevelopment project that creates 5,000 square feet or more of impervious surface collectively over the entire project site and supports a hillside development project? A hillside development project includes development on any natural slope that is twenty-five percent or greater X 5. Is your project a new or redevelopment project that creates 5,000 square feet or more of impervious surface collectively over the entire project site and supports a parking lot. A parking lot is a land area or facility for the temporary parking or storage of motor vehicles used personally for business or for commerce. X 6. Is your project a new or redevelopment project that creates 5,000 square feet or more of impervious surface collectively over the entire project site and supports a street, road, highway freeway or driveway? A street, road, highway, freeway or driveway is any paved impervious surface used for the transportation of automobiles, trucks, motorcycles, and other vehicles. X 7. Is your project a new or redevelopment project that creates or replaces 2,500 square feet or more of impervious surface collectively over the entire site, and discharges directly to an Environmentally Sensitive Area (ESA)? "Discharging Directly to" includes flow that is conveyed overland a distance of 200 feet or less from the project to the ESA. or conveyed in a pipe or open channel any distance as an isolated flow from the project to the ESA (i.e. not commingles with flows from adjacent lands).* X 8. Is your project a new development that supports an automotive repair shop? An automotive repair shop is a facility that is categorized in any one of the following Standard Industrial Classification (SIC) codes: 5013, 5014, 5541, 7532-7534, or 7536-7539. X 9. Is your project a new development that supports a retail gasoline outlet (RGO)? This category includes RGO's that meet the following criteria: (a) 5,000 square feet or more or (b) a project Average Daily Traffic (ADT) of 100 or more vehicles per day. X 10. Is your project a new or redevelopment project that results in the disturbance of one or more acres of land and are expected to generate pollutants post construction? K 11.1s your project located within 200 feet of the Pacific Ocean and (1) creates 2,500 square feet or more of impervious surface or (2) increases impervious surface on the property by more than 10%? K If you answered "yes" to one or more of the above questions, you ARE a priority development project and are therefore subject to implementing structural Best Management Practices (BMP's) in addition to implementing Standard Storm Water Requirements such as source control and low impact development BMP's. A Storm Water Management Plan (SWMP) must be submitted with your application(s) for development. Go to step 3 for redevelopment projects. For new projects, go to step 4 at the end of this questionnaire, check the "my project meets PDP requirements" box and complete applicant Information. If you answered "no" to all of the above questions, you ARE NOT a priority development project and are therefore subject to implementing only Standard Storm Water Requirements such as source control and low impact development BMP's required for all development projects. A Storm Water Management Plan (SWMP) is not required with your application(s) for development. Go to step 4 at the end of this questionnaire, check the "my project does not meet PDP requirements" box and complete applicant information. E-34 Page 2 of 3 Effective 6/27/13 CITY OF CARLSBAD STORM WATER STANDARDS QUESTIONNAIRE E-34 Development Services Land Development Engineering 1635 Faraday Avenue 760-602-2750 www.carlsbadca.gov STEPS TO BE COMPLETED FOR REDEVELOPMENT PROJECTS THAT ARE PRIORITY DEVELOPEMENT PROJECTS ONLY Complete the questions below regarding your redevelopment project: YES NO Does the redevelopment project result in the creation or replacement of impervious surface in an amount of less than 50% of the surface area of the previously existing development? If you answered "yes," the structural BMP's required for Priority Development Projects apply only to the creation or replacement of impervious surface and not the entire development. Go to step 4, check the "my project meets PDP requirements" box and complete applicant information. If you answered "no," the structural BMP's required for Priority Development Projects apply to the entire development. Go to step 4, check the "my project meets PDP requirements" box and complete appiicant information. STEP 4 CHECK THE APPROPRIATE BOX AND COMPLETE APPLICANT INFORMATION My project meets PRIORITY DEVELOPMENT PROJECT (PDP) requirements and must comply with additional stormwater criteria per the SUSMP and I understand I must prepare a Storm Water Management Plan for submittal at time of application. I understand flow control (hydromodification) requirements may apply to my project. Refer to SUSMP for details. • My project does not meet PDP requirements and must only comply with STANDARD STORMWATER REQUIREMENTS per the SUSMP. As part of these requirements, I will incorporate low impact development strategies throughout my project. Applicant Information and Signature Box Address: Accessor's Parcel Number(s): Applicant Name: Applicant Title: Applicant Signature: Date: This Box for City Use Only City Concurrence: YES NO By: Date: Project ID: * Environmentally Sensitive Areas include but are not limited to all Clean Water Act Section 303(d) impaired water bodies; areas designated as Areas of Special Biological Significance by the State Water Resources Control Board (Water Quality Control Plan for the San Diego Basin (1994) and amendments); water bodies designated with the RARE beneficial use by the State Water Resources Control Board (Water Quality Control Plan for the San Diego Basin (1994) and amendments); areas designated as preserves or their quivalent under the Multi Species Conservation Program within the Cities and County of San Diego; and any other equivalent environmentally sensitive areas which have been identified by the Copermittees. E-34 Page 3 of 3 Effective 6/27/13 ATTACHMENT 2 BMP AND DMA PLAN EXHIBIT ATTACHMENTS SWMM PROGRAM RESULTS TECHNICAL MEMORANDUM: SWMM Modeling for Hydromodification Compliance of: Carlsbad Raceway Lot 17 Prepared for: Burke Real Estate Group September 9, 2013 Prepared by: Luis Pirra, PhD, CPSWQ, ToR, D.WRE. R.C.E. 66377 TORY R. WALKER ENGINEERING, INC. WATER RESOURCES PLANNING & ENGINEERING 122 CIVIC CENTER DRIVE, SUITE 2oe, VISTA, CA 92084 PH:7G0-414-9212 WWW.TRWENGINEERING.COM TORY R. WALKER ENGINEERING, INC. WATER RESOURCES PLANNING 8C ENGINEERING TECHNICAL MEMORANDUM TO: Burke Real Estate Group FROM: Tory Walker, PE, CFM, LEED GA Luis Parra, PhD, PE, CPSWQ, ToR, D.WRE. DATE: September 9, 2013 RE: Summary of SWMM Modeling for Hydromodification Compliance for Carlsbad Raceway Lot 17, Carlsbad, CA. INTRODUCTION This memorandum summarizes the approach used to model the proposed commercial development project site in the City of Carlsbad using the Environmental Protection Agency (EPA) Storm Water Management Model 5.0 (SWMM). SWMM models were prepared for the pre and post-developed conditions at the site in order to determine if the proposed LID bioretention facilities have sufficient volume to meet the current Hydromodification Management Plan (HMP) requirements from the San Diego Regional Water Quality Control Board (SDRWQCB). SWMM MODEL DEVELOPMENT The Carlsbad Raceway Lot 17 project proposes a commercial building on the currently vacant property, with servicing parking lot and a receiving dock. Two (2) SWMM models were prepared for this study: the first for the pre-development and the second for the post-developed conditions. The project site drains to one (1) Point of Compliance (POC) located to the north-west of the project site located at an existing storm drain outlet draining to a natural channel. Regarding SWMM, it was used since we have found it to be more comparable to San Diego area watersheds than the alternative San Diego Hydrology Model (SDHM). For both SWMM models, flow duration curves were prepared to determine if the proposed HMP facility is sufficient to meet the current HMP requirements. The inputs required to develop SWMM models include rainfall, watershed characteristics, and BMP configurations. The Oceanside Gage from the Project Clean Water website was used for this study, since it is the most representative of the project site precipitation due to elevation and proximity to the project site. Evaporation for the site was modeled using average monthly values from the County hourly dataset. The site was modeled as with Type D hydrologic soil as this is the existing soil determined from the 2003 County of San Diego Hydrology Manual. Soils have been assumed to be compacted in the existing condition to represent the current mass graded condition of the site, while fully compacted in the post developed conditions. Other SWMM inputs for the subareas are discussed in the appendices to this document, where the selection ofthe parameters is explained in detail. 122 CIVIC CENTER DRIVE, SUITE 206, VISTA, OA 92084 | PH: 760.414.9212 Fx: 760.414.9277 IWWW.TRWENGINEERING.COM Carlsbad Raceway Lot 17 HMP Memo September 9, 2013 HMP MODELING DEVELOPED CONDITIONS Storm water runoff from the proposed project site is routed to a single POC located to the northwest of the project site. Runoff from the developed project site is drained to four (4) onsite receiving bioretention UD BMPs. Once flows are routed via the proposed LID BMPs, all flows are then conveyed via storm drain to the aforementioned POC. In accordance with water quality design criteria, a portion of the project site consisting of approximate 6,000 square feet of impervious loading dock areas do not drain to the bio-retention LID BMPs and are confluence directly at the POC. It is assumed all storm water quality requirements for the project will be met by the bioretention LID BMPs (as the minimum required treatment footprint area is met by the proposed BMP design). However, detailed water quality requirements are not discussed within this technical memo. For further information in regards to storm water quality requirements for the project, please refer to the site specific Storm Water Management Plan (SWMP). TABLE 1 - SUMMARY OF DEVELOPED CONDITIONS DMA Tributary Area, A (Ac)<^' Impervious Percentage, Ip Slope WQ 85'" Percentile'*' DMA Tributary Area, A (Ac)<^' Impervious Percentage, Ip Slope Area Required (ft^) Area Provided (ft') DMAl 0.564 70.96% 1% 734 2,016 DMA 2 1.347 90.58% 1% 2,166 4,489 DMA 3 2.323 81.32% 1% 3,381 3,462 DMA 4'^' 0.110 81.82% 1% NA NA (1) (2) : (3) : draining to the IMP (simplified SUSIVIP equation) IIVIP Areas are subtracted from the overall DIVIA to ensure areas are not double counted. BMP provided is not a bioretention basin rather a proprietary Contech Bioretention BMP vault system sized to provide sufficient treatment for the 85* percentile flow. Three (3) LID bioretention basins are located within the project site and are responsible for handling hydromodification requirements for the majority of the project site. A small 0.11 acre portion of the southwestern parking lot drains to a proprietary Contech bioretention vault prior to discharging to the POC. This vault has been modeled within the SWMM model for developed conditions using the vault footprint area provided for bio retention treatment and a media filtration rate of 100-inches/hr (representative of the treatment media within the vault). In developed conditions, the basins will have a surface depth of 1.32 to 1.4 feet and a riser spillway structure (see dimensions in Table 2). Flows will then discharge from the basins via a low flow orifice outlet within the gravel layer. The riser structure will act as a spillway such that peak flows can be safely discharged to the receiving storm drain system. Regarding ponding elevations, table 3 on the following page illustrates the respective top, bottom and riser elevations accordingly. W.O.313-1 Carlsbad Raceway Lot 17 HMP Memo September 9, 2013 Beneath the basins' invert lies the proposed UD bioretention portion of the drainage facility. This portion of the basin is comprised of a 3-inch layer of mulch, a 24-inch layer of amended soil (a highly sandy, organic rich composite with an infiltration capacity of at least 5 inches/hr) and a 6-inch layer of gravel for additional detention and to accommodate the French drain systems. These systems are to be located beneath the bioretention layers to intercept treated storm water and convey these flows to a small diameter lower outlet orifice. Once flows have been routed by the outlet structure, flows are then discharged to the receiving POC discharge location. The bioretention basins were modeled using the bioretention LID module within SWMM. The bioretention module can model the underground gravel storage layer, underdrain with an orifice plate, amended soil layer, and a surface storage pond up to the elevation of the invert of the spillway. It should be noted that detailed outlet structure locations and elevations will be shown on the construction plans based on the recommendations of this study. BMP MODELING FOR HMP PURPOSES Modeling of dual purpose Water Quality/HMP BMPs Four (4) LID BMP bioretention basins are proposed for water quality treatment and hydromodification conformance for the project site. Table 2 illustrates the dimensions required for HMP compliance according to the SWMM model that was undertaken for the project. TABLE 2 - SUMMARY OF DEVELOPED DUAL PURPOSE BMPS: BMP Impervious Tributary Area (Ac) DIMENSIONS BMP Impervious Tributary Area (Ac) Area'*', (ft') Gravel Depth'^' (in) Lower Orif. D (in)'^' Depth Riser Invert (in)'*' Riser Perimeter Length (ft) Total Surface Depth'" (in) 1 0.400 2,016 6 1.25 10 12 15.8 2 1.220 4,489 6 1.50 10 12 16.8 3 1.889 3,462 6 1.75 10 12 16.8 4 0.090 17 6 0.75 6 NA 36 Notes: (1): Area of amended soil equal to area of gravel (2) : Gravel depth needed to comply with hydromodification purposes (3) : Diameter of orifice in gravel layer with invert at bottom of layer; tied with hydromod min threshold (0.I Q2). (4) : Depth of ponding beneath riser structure's surface spillway. (5) : Overflow length, the internal perimeter ofthe riser Is 12 ft (3 ft x 3 ft internal dimensions). (6) : Total surface depth of BMP from top crest elevation to surface invert. W.O.313-1 Carlsbad Raceway Lot 17 HMP Memo September 9, 2013 TABLE 3 - SUMMARY OF BIO RETENTION BASINS RELATIVE ELEVATIONS: BMP Basin Surface Elevation (ft) Riser Elevation (ft) Basin Top Elevation (ft) 1 395.00 395.83 396.32 2 393.30 394.13 394.70 3 392.20 393.03 393.60 FLOW DURATION CURVE COMPARISON The Flow Duration Curve (FDC) for the site was compared at the POC by exporting the hourly runoff time series results from SWMM to a spreadsheet. The FDC was compared between 10% of the existing condition Qa up to the existing condition Qio. The Q2 and Qio were determined with a partial duration statistical analysis of the runoff time series in an Excel spreadsheet using the Cunnane plotting position method (which is the preferred plotting methodology in the HMP Permit). As the SWMM Model includes a statistical analysis based on the Weibull Plotting Position Method, the Weibull Method was also used within the spreadsheet to ensure that the results were similar to those obtained by the SWMM Model. The range between 10% of Q2 and Qio was divided into 100 equal time intervals; the number of hours that each flow rate was exceeded was counted from the hourly series. Additionally, the intermediate peaks with a return period "i" were obtained (Q, with i=3 to 9). For the purpose of the plot, the values were presented as percentage of time exceeded for each flow rate. FDC comparison at the POC is illustrated in Figure 1 in both normal and logarithmic scale. Attachment 5 provides a detailed drainage exhibit for the post-developed condition. As can be seen in Figure 1, the FDC for the proposed condition with the HMP BMPs is within 110% of the curve for the existing condition in both peak flows and durations. The additional runoff volume generated from developing the site will be released to the existing point of discharge at a flow rate below the 10% Q2 lower threshold. Additionally, the project will also not increase peak flow rates between the Q2 and the Qw, as shown in the graphic and also in the peak flow tables in Attachment 1. SUMMARY This study has demonstrated that the proposed and interim HMP BMPs provided for the Carlsbad Raceway Lot 17 site is sufficient to meet the current HMP criteria if the cross-section areas and volumes recommended within this technical memorandum, and the respective orifices and outlet structures are incorporated as specified within the proposed project site. KEY ASSUMPTIONS 1. Type D Soil is representative ofthe existing condition site. W.O.313-1 Carlsbad Raceway Lot 17 HMP Memo September 9, 2013 ATTACHMENTS 1. Q2 to Qio Comparison Tables 2. FDC Plots (log and natural "x" scale) and Flow Duration Table. 3. List of the "n" largest Peaks: Pre-Development and Post-Development Conditions 4. Elevation vs. Area Curves and Elevations vs. Discharge Curves to be used in SWMM 5. Pre & Post Development Maps, Project plan and section sketches 6. SWMM Input Data in Input Format (Existing and Proposed Models) 7. SWMM Screens and Explanation of Significant Variables 8. Soil Map 9. Summary files from the SWMM Model W.O.313-1 Carlsbad Raceway Lot 17 HMP Memo September 9, 2013 Raceway 17 - Flow Duration Curve Percei^age of time exceeded (%} Raceway 17 - Flow Duration Curve f—iQioi 0.1 0.15 Percentage of tilT^ exceeded |K} Figure la and lb. Flow Duration Curve Comparison (logarithmic and normal "x" scale) W.O.313-1 Carlsbad Raceway Lot 17 HMP Memo September 9, 2013 ATTACHMENT 1. Qz to Qio Comparison Table - POC 1 Return Period Existing Condition (cfs) Mitigated Condition (cfs) Reduction, Exist - Mitigated (cfs) 2-year 2.386 1.436 0.950 3-year 2.717 1.601 1.116 4-year 3.079 1.909 1.170 5-year 3.126 2.157 0.969 6-year 3.226 2.348 0.878 7-year 3.420 2.471 0.949 8-year 3.516 2.682 0.834 9-year 3.676 2.782 0.894 10-year 3.873 2.793 1.080 W.O.313-1 ATTACHMENT 2 FLOW DURATION CURVE ANALYSIS 1) Flow duration curve shall not exceed the existing conditions by more than 10%, neither in peak flow nor duration. The figures on the following pages illustrate that the flow duration curve In post-development conditions after the proposed BMP is below the existing flow duration curve. The flow duration curve table following the curve shows that if the interval O.IOQ2 - Qio is divided in 100 sub- intervals, then a) the post development divided by pre-development durations are never larger than 110% (the permit allows up to 110%); and b) there are no more than 10 intervals in the range 101%-110% which would imply an excess over 10% ofthe length ofthe curve (the permit allows less than 10% of excesses measured as 101-110%). Consequently, the design passes the hydromodification test. It is important to note that the flow duration curve can be expressed in the "x" axis as percentage of time, hours per year, total number of hours, or any other similar time variable. As those variables only differ by a multiplying constant, their plot in logarithmic scale is going to look exactly the same, and compliance can be observed regardless of the variable selected. However, in order to satisfy the City of Carlsbad HMP example, % of time exceeded is the variable of choice in the flow duration curve. The selection of a logarithmic scale in lieu of the normal scale is preferred, as differences between the pre-development and post-development curves can be seen more clearly in the entire range of analysis. Both graphics are presented just to prove the difference. In terms of the "y" axis, the peak flow value is the variable of choice. As an additional analysis performed by TRWE, not only the range of analysis is clearly depicted (10% of Q2 to Qio) but also all intermediate flows are shown (Q2, Q3, Q4, Q5, Qe, Q7, Qs and Qg) in order to demonstrate compliance at any range Qx - Qx+i. It must be pointed out that one of the limitations of both the SWMM and SDHM models is that the intermediate analysis is not performed (to obtain Qi from i = 2 to 10). TRWE performed the analysis using the Cunnane Plotting position Method (the preferred method in the HMP permit) from the "n" largest independent peak flows obtained from the continuous time series. The largest "n" peak flows are attached in this appendix, as well as the values of Qi with a return period "i", from i=2 to 10. The Qi values are also added into the flow-duration plot. Raceway 17 - Flow Duration Curve 4.00 •|--iQio •I l-Qo r 1^ -0.SQ2 3Q| 0.001 0.01 0.1 Percentage of time exceeded (%) Raceway 17 - Flow Duration Curve 4.00 I f r -p.3Q, 0.05 0.1 0.15 Percentage of time exceeded (%) 0.25 Flow Duration Curve Data for Raceway Lot 17, Carlsbad CA - POC 1 Q2 = Q10 = Step = Count •• 2.39 cfs 3.87 cfs 0.0367 cfs 499679 hours 57.00 years Fraction 10 % Interval Existing Condition Detention Optimized Pass or Fail? Interval Q(cfs) Hours > Q %time Hours>Q %time Post/Pre Pass or Fail? 1 0.239 1052 2.11E-01 641 1.28E-01 61% Pass 2 0.275 952 1.91E-01 553 l.llE-01 58% Pass 3 0.312 857 1.72E-01 485 9.71E-02 57% Pass 4 0.349 780 1.56E-01 405 8.11E-02 52% Pass 5 0.385 707 1.41E-01 365 7.30E-02 52% Pass 6 0.422 656 1.31E-01 327 6.54E-02 50% Pass 7 0.459 609 1.22E-01 293 5.86E-02 48% Pass 8 0.496 562 1.12E-01 263 5.26E-02 47% Pass 9 0.532 517 1.03E-01 239 4.78E-02 46% Pass 10 0.569 479 9.59E-02 216 4.32E-02 45% Pass 11 0.606 444 8.89E-02 184 3.68E-02 41% Pass 12 0.642 419 8.39E-02 176 3.52E-02 42% Pass 13 0.679 390 7.81E-02 166 3.32E-02 43% Pass 14 0.716 372 7.44E-02 152 3.04E-02 41% Pass 15 0.753 341 6.82E-02 145 2.90E-02 43% Pass 16 0.789 317 6.34E-02 136 2.72E-02 43% Pass 17 0.826 295 5.90E-02 127 2.54E-02 43% Pass 18 0.863 270 5.40E-02 106 2.12E-02 39% Pass 19 0.899 251 5.02E-02 95 1.90E-02 38% Pass 20 0.936 234 4.68E-02 88 1.76E-02 38% Pass 21 0.973 225 4.50E-02 83 1.66E-02 37% Pass 22 1.009 214 4.28E-02 80 1.60E-02 37% Pass 23 1.046 200 4.00E-02 77 1.54E-02 39% Pass 24 1.083 190 3.80E-02 68 1.36E-02 36% Pass 25 1.120 183 3.66E-02 58 1.16E-02 32% Pass 26 1.156 170 3.40E-02 57 1.14E-02 34% Pass 27 1.193 151 3.02E-02 54 1.08E-02 36% Pass 28 1.230 140 2.80E-02 49 9.81E-03 35% Pass 29 1.266 127 2.54E-02 44 8.81E-03 35% Pass 30 1.303 124 2.48E-02 43 8.61E-03 35% Pass 31 1.340 117 2.34E-02 40 8.01E-03 34% Pass 32 1.377 109 2.18E-02 38 7.60E-03 35% Pass 33 1.413 106 2.12E-02 36 7.20E-03 34% Pass 34 1.450 104 2.08E-02 35 7.00E-03 34% Pass 35 1.487 100 2.00E-02 31 6.20E-03 31% Pass 36 1.523 95 1.90E-02 31 6.20E-03 33% Pass Interval Existing Condition Detention Optimized Pass or Fail? Interval Q(cfs) Hours > Q %time Hours>Q %time Post/Pre Pass or Fail? 37 1.560 89 1.78E-02 31 6.20E-03 35% Pass 38 1.597 88 1.76E-02 31 6.20E-03 35% Pass 39 1.634 79 1.58E-02 24 4.80E-03 30% Pass 40 1.670 73 1.46E-02 22 4.40E-03 30% Pass 41 1.707 63 1.26E-02 22 4.40E-03 35% Pass 42 1.744 61 1.22E-02 21 4.20E-03 34% Pass 43 1.780 59 1.18E-02 21 4.20E-03 36% Pass 44 1.817 57 1.14E-02 20 4.00E-03 35% Pass 45 1.854 57 1.14E-02 19 3.80E-03 33% Pass 46 1.890 56 1.12E-02 18 3.60E-03 32% Pass 47 1.927 50 l.OOE-02 18 3.60E-03 36% Pass 48 1.964 49 9.81E-03 17 3.40E-03 35% Pass 49 2.001 47 9.41E-03 17 3.40E-03 36% Pass 50 2.037 46 9.21E-03 16 3.20E-03 35% Pass 51 2.074 42 8.41E-03 16 3.20E-03 38% Pass 52 2.111 41 8.21E-03 15 3.00E-03 37% Pass 53 2.147 40 8.01E-03 15 3.00E-03 38% Pass 54 2.184 38 7.60E-03 14 2.80E-03 37% Pass 55 2.221 37 7.40E-03 13 2.60E-03 35% Pass 56 2.258 37 7.40E-03 13 2.60E-03 35% Pass 57 2.294 36 7.20E-03 13 2.60E-03 36% Pass 58 2.331 34 6.80E-03 12 2.40E-03 35% Pass 59 2.368 34 6.80E-03 12 2.40E-03 35% Pass 60 2.404 30 6.00E-03 12 2.40E-03 40% Pass 61 2.441 30 6.00E-03 10 2.00E-03 33% Pass 62 2.478 29 5.80E-03 10 2.00E-03 34% Pass 63 2.515 29 5.80E-03 9 1.80E-03 31% Pass 64 2.551 28 5.60E-03 9 1.80E-03 32% Pass 65 2.588 27 5.40E-03 9 1.80E-03 33% Pass 66 2.625 25 5.00E-03 9 1.80E-03 36% Pass 67 2.661 23 4.60E-03 9 1.80E-03 39% Pass 68 2.698 22 4.40E-03 8 1.60E-03 36% Pass 69 2.735 22 4.40E-03 8 1.60E-03 36% Pass 70 2.772 21 4.20E-03 8 1.60E-03 38% Pass 71 2.808 21 4.20E-03 8 1.60E-03 38% Pass 72 2.845 21 4.20E-03 8 1.60E-03 38% Pass 73 2.882 20 4.00E-03 7 1.40E-03 35% Pass 74 2.918 19 3.80E-03 6 1.20E-03 32% Pass 75 2.955 19 3.80E-03 6 1.20E-03 32% Pass 76 2.992 19 3.80E-03 6 1.20E-03 32% Pass 77 3.028 19 3.80E-03 6 1.20E-03 32% Pass 78 3.065 17 3.40E-03 6 1.20E-03 35% Pass 79 3.102 16 3.20E-03 5 l.OOE-03 31% Pass 80 3.139 13 2.60E-03 5 l.OOE-03 38% Pass 81 3.175 11 2.20E-03 4 8.01E-04 36% Pass Interval Existing Condition Detention Optimized Pass or Fail? Interval Q(cfs) Hours > Q %time Hours>Q %time Post/Pre Pass or Fail? 82 3.212 10 2.00E-03 4 8.01E-04 40% Pass 83 3.249 9 1.80E-03 4 8.01E-04 44% Pass 84 3.285 9 1.80E-03 4 8.01E-04 44% Pass 85 3.322 9 1.80E-03 4 8.01E-04 44% Pass 86 3.359 9 1.80E-03 4 8.01E-04 44% Pass 87 3.396 9 1.80E-03 3 6.00E-04 33% Pass 88 3.432 8 1.60E-03 3 6.00E-04 38% Pass 89 3.469 7 1.40E-03 3 6.00E-04 43% Pass 90 3.506 7 1.40E-03 3 6.00E-04 43% Pass 91 3.542 7 1.40E-03 3 6.00E-04 43% Pass 92 3.579 7 1.40E-03 3 6.00E-04 43% Pass 93 3.616 6 1.20E-03 3 6.00E-04 50% Pass 94 3.653 6 1.20E-03 2 4.00E-04 33% Pass 95 3.689 6 1.20E-03 2 4.00E-04 33% Pass 96 3.726 6 1.20E-03 2 4.00E-04 33% Pass 97 3.763 6 1.20E-03 2 4.00E-04 33% Pass 98 3.799 6 1.20E-03 2 4.00E-04 33% Pass 99 3.836 6 1.20E-03 2 4.00E-04 33% Pass 100 3.873 6 1.20E-03 2 4.00E-04 33% Pass Peak Flows calculated with Cunnane Plotting Position Return Period Pre-dev. Q Post-Dev. Q Reduction 10 3.873 2.793 1.080 9 3.676 2.782 0.894 8 3.516 2.682 0.834 7 3.420 2.471 0.949 6 3.226 2.348 0.878 5 3.126 2.157 0.969 4 3.079 1.909 1.170 3 2.717 1.601 1.116 2 2.386 1.436 0.950 ATTACHMENTS List ofthe "n" Largest Peaks: Pre & Post-Developed Conditions List of Peak events and Determination of P2 and PIO (Post-Development) Raceway 17 - POC 1 T Cunnane Weibull Period of Return 10 2.79 2.83 Peaks Date Posit Weibull Cunnane 9 2.78 2.79 1.005 1/9/1980 57 1.02 1.01 8 2.68 2.73 1.009 1/25/1969 56 1.04 1.03 7 2.47 2.54 1.019 12/24/1971 55 1.05 1.05 6 2.35 2.36 1.021 11/18/1986 54 1.07 1.07 5 2.16 2.19 1.026 12/28/2004 53 1.09 1.09 4 1.91 1.92 1.041 2/22/2005 52 1.12 1.11 3 1.60 1.60 1.05 12/25/1983 51 1.14 1.13 2 1.44 1.44 1.057 1/11/1980 50 1.16 1.15 1.057 12/24/1988 49 1.18 1.18 1.059 2/18/1980 48 1.21 1.20 Note: 1.061 2/13/1992 47 1.23 1.23 Cunnane is the preferred 1.062 11/30/2007 46 1.26 1.25 method by the HMP permit. 1.114 2/12/2003 45 1.29 1.28 1.126 1/14/1993 44 1.32 1.31 1.144 2/6/1969 43 1.35 1.34 1.151 2/18/2005 42 1.38 1.38 1.161 3/5/1995 41 1.41 1.41 1.175 1/20/1962 40 1.45 1.44 1.183 3/3/1983 39 1.49 1.48 1.193 4/27/1960 38 1.53 1.52 1.224 1/11/2005 37 1.57 1.56 1.256 11/22/1996 36 1.61 1.61 1.27 8/17/1977 35 1.66 1.65 1.302 9/23/1986 34 1.71 1.70 1.307 1/16/1972 33 1.76 1.75 1.307 3/2/1980 32 1.81 1.81 1.326 2/17/1998 31 1.87 1.87 1.434 1/16/1978 30 1.93 1.93 1.436 1/9/2005 29 2.00 2.00 1.447 1/16/1993 28 2.07 2.07 1.562 2/10/1978 27 2.15 2.15 1.567 2/3/1998 26 2.23 2.23 1.568 12/30/1991 25 2.32 2.33 1.578 3/8/1968 24 2.42 2.42 1.58 1/15/1978 23 2.52 2.53 1.582 1/13/1997 22 2.64 2.65 1.583 2/23/2005 21 2.76 2.78 1.6 1/6/1979 20 2.90 2.92 1.602 2/23/1998 19 3.05 3.08 1.766 2/22/2008 18 3.22 3.25 1.78 2/15/1986 17 3.41 3.45 1.804 1/16/1952 16 3.63 3.67 1.892 3/1/1991 15 3.87 3.92 1.952 10/27/2004 14 4.14 4.21 2.012 2/4/1958 13 4.46 4.54 2.136 2/25/2003 12 4.83 4.93 2.28 1/29/1980 11 5.27 5.40 2.346 11/22/1965 10 5.80 5.96 2.377 3/17/1982 9 6.44 6.65 2.613 2/20/1980 8 7.25 7.53 2.778 3/1/1978 7 8.29 8.67 2.795 10/1/1983 6 9.67 10.21 3.01 2/25/1969 5 11.60 12.43 3.08 1/4/1978 4 14.50 15.89 3.548 1/15/1979 3 19.33 22.00 4.421 1/4/1995 2 29.00 35.75 5.022 4/14/2003 1 58.00 95.33 List of Peak events and Determination of P2 and PIG (Pre-Development) T Cunnane Weibull Period of Return 10 3.87 3.99 Peal<s Date Posit Weibull Cunnane 9 3.68 3.77 1.701 1/11/1980 57 1.02 1.01 8 3.52 3.57 1.707 2/23/2005 56 1.04 1.03 7 3.42 3.43 1.732 4/28/2005 55 1.05 1.05 6 3.23 3.27 1.754 1/11/2005 54 1.07 1.07 5 3.13 3.13 1.807 3/1/1991 53 1.09 1.09 4 3.08 3.09 1.817 2/22/1998 52 1.12 1.11 3 2.72 2.73 1.866 8/17/1977 51 1.14 1.13 2 2.39 2.39 1.892 12/25/1968 50 1.16 1.15 1.895 2/8/1993 49 1.18 1.18 1.916 3/19/1981 48 1.21 1.20 Note: 1.916 2/12/1992 47 1.23 1.23 Cunnane is the preferred 1.919 12/22/1982 46 1.26 1.25 method by the HIV1P permit. 1.925 4/27/1960 45 1.29 1.28 1.932 2/14/1998 44 1.32 1.31 1.977 3/15/1986 43 1.35 1.34 1.991 3/11/1995 42 1.38 1.38 2.034 1/16/1972 41 1.41 1.41 2.071 2/15/1986 40 1.45 1.44 2.073 1/18/1993 39 1.49 1.48 2.083 12/2/1961 38 1.53 1.52 2.138 3/17/1963 37 1.57 1.56 2.154 1/29/1980 36 1.61 1.61 2.159 2/4/1994 35 1.66 1.65 2.213 1/16/1978 34 1.71 1.70 2.288 10/20/2004 33 1.76 1.75 2.317 2/17/1998 32 1.81 1.81 2.328 2/18/1993 31 1.87 1.87 2.373 11/15/1952 30 1.93 1.93 2.386 2/27/1983 29 2.00 2.00 2.392 2/16/1980 28 2.07 2.07 2.404 11/11/1985 27 2.15 2.15 2.477 2/23/1998 26 2.23 2.23 2.546 12/30/1991 25 2.32 2.33 2.562 1/29/1983 24 2.42 2.42 2.6 11/22/1965 23 2.52 2.53 2.632 2/3/1998 22 2.64 2.65 2.64 12/19/1970 21 276 2.78 2.673 2/10/1978 20 2.90 2.92 2.758 3/2/1980 19 3.05 3.08 2.856 4/1/1958 18 3.22 3.25 3.031 3/17/1982 17 3.41 3.45 3.046 3/1/1978 16 3.63 3.67 3.066 1/16/1952 15 3.87 3.92 3.112 1/14/1993 14 4.14 4.21 3.112 10/29/2000 13 4.46 4.54 3.121 2/20/1980 12 4.83 4.93 3.156 2/18/2005 11 5.27 5.40 3.215 10/27/2004 10 5.80 5.96 3.401 2/25/1969 9 6.44 6.65 3.449 2/4/1958 8 7.25 7.53 3.61 2/25/2003 7 8.29 8.67 3.915 9/23/1986 6 9.67 10.21 4.342 1/4/1995 5 11.60 12.43 4.509 1/15/1979 4 14.50 15.89 4.797 10/1/1983 3 19.33 22.00 4.913 1/4/1978 2 29.00 35.75 5.326 4/14/2003 1 58.00 95.33 ATTACHMENT 4 AREA VS ELEVATION The LID module allows for the direct input of surface storage depth and BMP footprint area to determine surface ponded volume. As such no stage-storage calculations are required for this analysis. DISCHARGE VS ELEVATION The orifice has been selected to maximize their size while still restricting flows to conform with the required 10% of the Q2 event flow as mandated in the Final Hydromodification Management Plan by Brown & Caldwell, dated March 2011. While TRWE acknowledges that these orifices are small, to increase the size of these outlets would impact the basin's ability to restrict flows beneath the HMP thresholds, thus preventing the BMP from conformance with HMP requirements. In order to further reduce the risk of blockage of the orifices, regular maintenance of the riser and orifices must be performed to ensure potential blockages are minimized. A detail of the orifice and riser structure is provided in Attachment 5 of this memorandum. No stage-storage calculations were performed for the ultimate condition as there are no surface orifices; all flows drain via the low flow orifice beneath the HMP facility or via the emergency spillway to the receiving storm drain system. ATTACHMENTS Pre & Post-Developed Maps, Project Plan and Detention Section Sketches GRAVEL LAYER EXIST. GROUND RISER OUTLET STRUCTURE 24" AMENDED SOIL MIN. INFILTRATION RA TE 5"/HR. ^ BASIN TOP ELEV BASIN INVERT BOTTOM OF AMENDED SOIL LID INVERT-BOTTOM OF GRAVEL UD ORIFICE BIORETENTION AREA BIORETENTION AREA CROSS SECTION (TYP) NOT TO SCALE BMP H(FT) Hmax{FT) Hg(FT) LID (INCHES) Ag(FT^2) Abot(FT^2) 1 0.83 1.32 0.5 1.25 2016 2016 2 0.83 1.4 0.5 1.5 4489 4489 3 0.83 1.4 0.5 1.75 3462 3003 RISER WALL FRENCH DRAIN GRA VEL STORAGE LA YER RESTRICTOR PLATE LID ORIFICE DETAIL NOT TO SCALE ATTACHMENTS SWMM Input Data in Input Format (Existing & Proposed Models) [TITLE] POST DEV [OPTIONS] FLOW_UNITS INFILTRATION FLOW_ROUTING START_DATE START_TIME RE PORT_S TART_DATE REPOBT_START_TIME END_DATE END_TIME SWEEP_START SWEEP_END DRY_DAYS REPORT_STEP WET_STEP DRY_STEP ROUTING_STEP ALLOW_PONDING INERTIAL_DAMPING VARIABLE_STEP LENGTHENING_STEP MIN_SORFAREA NORMAL_FLOW_LIMITED SKIP_STEADY_STATE FORCE_MAIN_EQUATION LINK_OFFSETS MIN SLOPE CFS GREEN_AMPT KINWAVE 10/01/1951 00:00:00 10/01/1951 00:00:00 09/30/2008 23:00:00 01/01 12/31 0 01:00:00 00:15:00 04:00:00 0:01:00 NO PARTIAL 0.75 0 0 BOTH NO H-W DEPTH 0 (EVAPORATION] ;;Type Parameters MONTHLY .041 .076 .118 .192 .237 .318 .308 .286 .217 .14 .067 .041 DRY ONLY NO [RAINGAGES] ; ; Rain Time Snow Data ;;Name Type Intrvl Catch Source Oceanside INTENSITY 1:00 1.0 TIMESERIES Oceanside [SUBCATCHMENTS] Total Pent. Pent. Curb ;;Name Raingage Outlet Area Imperv Width Slope Length ;Subarea A w/o bioretention DMA-1 Oceanside BR-1 0 .564 70.96 71 1 0 BR-1 Oceanside POC-1 0 .046281 0 10 0 0 DMA-2 Oceanside BR-2 1 .347 90.58 128 1 0 BR-2 Oceanside POC-1 0 .103053 0 10 0 0 DMA-3 Oceanside BR-3 2 .323 81.32 172 1 0 BR-3 Oceanside POC-1 0 .079477 0 10 0 0 DMA-4 Oceanside BR-4 0 .11 81.82 42 1 0 BR-4 Oceanside POC-1 0 .000391 0 10 0 0 DMA-BYPASS Oceanside POC-1 0 .13774 100 50 1 0 [SUBAREAS] ;;Subcatchment N-Imperv N-Perv S -Imperv S-Perv PctZero RouteTo PctRouted DMA-1 .012 0.05 02 .1 25 OUTLET BR-1 0.012 0.1 02 .1 25 OUTLET Snow PacJc POST DEV DMA-2 BR-2 DMA-3 BR-3 DMA-4 BR-4 DMA-BYPASS .012 .012 .012 0.012 .012 0.012 .012 0 . 05 0.05 0.05 0.1 0.05 0.1 0.05 .02 .02 .02 .02 .02 .02 .02 25 25 25 25 25 25 25 OUTLET OUTLET OUTLET OUTLET OUTLET OUTLET OUTLET [INFILTRATION] ; ; Subcatchment Suction HydCon IMDmax DMA-1 9 0 01875 0 3 BR-1 9 0 01875 0 3 DMA-2 9 0 01875 0 3 BR-2 9 0 01875 0 3 DMA-3 9 0 01875 0 3 BR-3 9 0 01875 0 3 DMA-4 9 0 01875 0 3 BR-4 9 0 01875 0 3 DMA-BY PASS 9 0 01875 0 3 [LID CONTROLS] LID-1 LID-1 LID-1 LID-1 LID-1 Type/Layer Parameters BC SURFACE SOIL STORAGE DRAIN 11.158 24 6 0.2581 05 4 67 5 1. 5 LID-2 LID-2 LID-2 LID-2 LID-2 BC SURFACE SOIL STOI^GE DRAIN 10.915 24 6 0.1669 0.05 0.4 0.67 0.5 0.0 0.2 0 0 0.0 0.1 0 6 1.5 LID-3 LID-3 LID-3 LID-3 LID-3 BC SURFACE SOIL STORAGE DRAIN 9.3 24 6 0.2945 0.05 0.4 0.67 0.5 0.0 0.2 0 0 0.0 0.1 0 6 1.5 LID-4 LID-4 LID-4 LID-4 LID-4 BC SURFACE SOIL STORAGE DRAIN 6 24 11.0171 0.0 0.4 0.67 0.5 0.0 0.2 0 0 0.0 0.1 0 6 5 100 1.5 [LID_USAGE] ;; Subcatchment LID Process Number Area Width InitSatur Fromlmprv ToPerv Report File "BR-A.txt" BR-1 BR-2 BR-3 BR-4 LID-1 LID-2 LID-3 LID-4 2016 4489 3462 17 100 100 100 100 [OUTFALLS] Name POC-1 Invert Elev. Outfall Type FREE Stage/Table Time Series Tide Gate NO POST DEV [TIMESERIES] ;;Name Date Time Value Oceanside FILE "OsideRain.prn" [REPORT] INPUT NO CONTROLS NO SUBCATCHMENTS ALL NODES ALL LINKS ALL [TAGS] [MAP] DIMENSIONS 0.000 0.000 10000.000 10000.000 Units None [COORDINATES] ;;Node X-Coord Y-Coord POC-1 0.000 3300.000 [VERTICES] ;;Link X-Coord Y-Coord [Polygons] ;;Subcatchment X-Coord Y-Coord t r DMA-1 -1500.000 9200.000 BR-1 -1500.000 7200.000 DMA-2 -500.000 9200.000 BR-2 -500.000 7200.000 DMA-3 500.000 9200.000 BR-3 500.000 7200.000 DMA-4 1500.000 9200.000 BR-4 1500.000 7200.000 DMA-BYPASS 2000.000 3300.000 [SYMBOLS] ;;Gage X-Coord Y-Coord Oceanside 6079.665 8029.350 [TITLE] PRE DEV [OPTIONS] FLOW_UNITS INFILTRATION FLOW_ROUTING START_DATE START_TIME REPORT_START_DATE RE PORT_S T ART_T IME END_DATE END_TIME SWEEP_START SWEEP_END DRY_DAYS REPORT_STEP WET_STEP DRY_STEP ROUTING_STEP ALL0W_PONDING INERTIAL_DAMPING VARIABLE_STEP LENGTHENING_STEP MIN^SURFAREA NORMAL_FLOW_LIMITED SKIP_S TEADY_S TATE FORCE_MAIN_EQUATION LINK_OFFSETS MIN SLOPE CFS GREEN_AMPT KINWAVE 10/17/1948 00:00:00 10/17/1948 00:00:00 10/17/2005 23:00:00 01/01 12/31 0 01:00:00 00:15:00 04:00:00 0:01:00 NO PARTIAL 0.75 0 0 BOTH NO H-W DEPTH 0 [EVAPORATION] ;;Type Parameters MONTHLY 0.041 0.076 0.118 0.192 0.237 0.318 0.308 0.286 0.217 0.14 0.067 0.041 DRY ONLY NO RAINGAGES] Name OCEANSIDE Rain Type Time Snow Data Intrvl Catch Source INTENSITY 1:00 1.0 TIMESERIES OCEANSIDE [SUBCATCHMENTS] Name Raingage Outlet Total Pent. Pont. Area Imperv Width Slope Curb Snow Length Pack DMA-1 OCEANSIDE POC-1 4.71 376 2.7 [SUBAREAS] ;;Subcatchment N-Imperv N-Perv S-Imperv S-Perv PctZero RouteTo PctRouted DMA-1 0.012 0.05 0.02 0.1 25 OUTLET [INFILTRATION] ;;Subcatchment Suction DMA-1 [OUTFALLS] Name Invert Elev. HydCon IMDmax 0.01875 0.3 Outfall Stage/Table Tide Type Time Series Gate PRE DEV POC-1 [TIMESERIES] ;; Name OCEANSIDE 0 FREE Date Time Value FILE "OsideRain.prn" NO [REPORT] INPUT NO CONTROLS NO SUBCATCHMENTS ALL NODES ALL LINKS ALL [TAGS] [MAP] DIMENSIONS 0.000 0.000 10000.000 10000.000 Units None [COORDINATES] ;;Node X-Coord Y-Coord POC-1 2500.000 2700.000 [VERTICES] ;;Link X-Coord Y-Coord [Polygons] ;;Subcatchment X-Coord Y-Coord DMA-1 DMA-1 2500.000 2500.000 6000.000 6000.000 [SYMBOLS] ;;Gage X-Coord Y-Coord OCEANSIDE 1525.424 6864.407 ATTACHMENT? EPASWIVIM FIGURES AND EXPLANATIONS Per the attached, the reader can see the screens associated with the EPA-SWMM Model in both pre-development and post-development conditions. Each portion, i.e., sub-catchments, outfalls, storage units, weir as a discharge, and outfalls (point of compliance), are also shown. Variables for modeling are associated with typical recommended values by the EPA-SWMM model, typical values found in technical literature (such as Maidment's Handbook of Hydrology). Recommended values for the SWMM model have been attained from the interim Orange County criteria established for their SWMM calibration. Currently, no recommended values have been established by the San Diego County HMP Permit for the SWMM Model. Soil characteristics of the existing soils were determined from the site specific geotechnical report. Some values incorporated within the SWMM model have been determined from the professional experience of TRWE using conservative assumptions that have a tendency to increase the size of the needed BMP and also generate a long-term runoff as a percentage of rainfall similar to those measured in gage stations in Southern California by the USGS. PRE-DEVELOPED CONDITION SWMM 5 PRE_DEV.mp File Edit Vipw Project Report Tools V/indow Help Data Map • Title/Nolet Options . Climaloiogy :i: Hydrology 'M- Hydraulics .ti Quality :*>• Curves Time Series Time Patterns •Map Labels Auto-Length Dl! ' • i o I V : CP ; © \ T •^."^ Study Aria M«p DMA-1 ZooniLovol lOO'i X,Y 3686.0 Outfall POC-1 Property Value POC-1 2500.000 2700.000 NO NO 0 NO FREE Fixed Stage 0 ^..'ILi—— tl Curve Name Series Name User-assigned name of outfall Rain Gage OCEANSIDE Property Value Name X-Coordinate Y-Coordinate Description Tag Rain Formal Time interval OCEANSIDE 1525.424 68G4.407 INTENSITY 1:00 Snow Catch Factor 1.0 Data Source TIMESERIES -Station ID • Rain Units IN User-assigned name of rain gage Subcatchment DMA-1 Property •Value Name DMA-1 X-Coordinate 2500.000 Y-Coordinate 6000.000 Description Tag Rain Gage OCEANSIDE Outlet POC-1 Area 4.71 Width 376 % Slope 2.7 % Imperv 0 N-Imperv 0.012 N-Perv 0.05 Dstore-lmperv 0.02 Dstore-Perv 0.1 ^ero-lmperv 25 Subarea Routing OUTLET Percent Routed 100 Infiltration GREEN_AMPT Groundwater NO Snow Pack LID Controls jo Land Uses 0 Initial Buildup NONE Curb Length 0 LID controls (click to edit) Infiltration Editor Infiltration Method ;GREEN_AMPT Properly 1 Value Suction Head j9 Conductivity 0.01875 Initial Deficit 0.3 Soil capillary suction head (inches or mm) - POST-DEVELOPED CONDITION .-.5 SWMM 5 - POST.DEV.REVJMP.inp File Edit View Project Report Toolt Window Help :Di^Bs:i%Mi9;?{i<^g£ it MI'S S %: Datd Map . r Tille/Nolei Options Climatology b! • Hydrology * ' Rain Gages \ ]•••• Subcatchmenls < < ' Aqu^ers ' , Snow Packs !' UnitHydtogtaphs UD Controls S" HydiaiJic* ', Nodes I i • - Junctions ; • i -Outfalls . Dividers ' Stoiage Units ' IB- Links ] • Transects • Controls • Quality it' • Cwves Time Series Time Patterns Map Labels ™ 4i AJo Lonolh on r^.^ Study Area Mxp Olfaels: Deptii "I El 1 10 OM:J!J1 01 00 01) DMA-1 OMA-2 DMA-3 WWW Oceanside BR-1 w BR-2 w BR-3 w BR-4 P Flow Umc |:F5 • JfH Zoom Level lOOJ: X.Y:-3600 852.10965309 Outfall POC-1 Property Series Name i Value lPOC-1 User-assigned name of outfall Rain Gage Oceanside Property Value Name X-Coordinate Y-Coordinate Description Tag Rain Format Time Interval Snow Catch Factor Data Source 1 lOceanside 6079.665 8029.350 INTENSITY 1:00 1,0 TIMESERIES - File Name - Station ID - Rain Units IN User-assigned name of rain gage Subcatchment DMA-1 liH Property Value iName DMA-1 X-Coordinate -1500.000 Y-Cootdinate 9200.000 Description jTag Rain Gage Oceanside j Outlet BR-1 lArea 0.564 Width 71 X Slope 1 X Imperv 70.96 N-Imperv .012 j N-Perv 0.05 Dstore-lmperv .02 i Dstore-Perv .1 ^ero-imperv 25 Subarea Routing OUTLET Percent Routed 100 Infiltration GREEN_AMPT 1 Groundwater NO Snow Pack LID Controls 0 i Land Uses 0 Initial Buildup NONE \ Curb Length 0 User-assigned name of subcatchment Subcatchment DMA-2 1^ Property j Value Name j DMA-2 X-Coordinate -500.000 Y-Coordinate 9200.000 Description Tag Rain Gage Oceanside Outlet BR-2 Area 1.347 Vi/idth 128 X Slope 1 Z Imperv 90.58 N-Imperv .012 N-Perv 0.05 Dstore-lmperv .02 Dstore-Perv .1 %Zero-lmperv 25 Subarea Routing OUTLET Percent Routed 100 Infiltration GREEN.AMPT Groundwater NO Snow Pack LID Controls 0 Land Uses 0 Initial Buildup NONE Curb Length 0 User-assigned name of subcatchment Subcatchment DMA-3 Property 1 Value Name iDMA-3 X-Coordinate 500.000 j Y-Coordinate 9200.000 i Description jTag Rain Gage Oceanside Outlet BR-3 Area 2.323 [width 172 Slope 1 i% Imperv 81.32 N-Imperv .012 1 N-Perv 0.05 1 Dstore-lmperv .02 Dstore-Perv .1 1 ^ero-lmperv 25 j Subarea Routing OUTLET Percent Routed 100 I Infiltration GREEN_AMPT I Groundwater NO jSnow Pack [LID Controls 0 Land Uses 0 1 Initial Buildup NONE j Curb Length 0 User-assigned name of subcatchment Subcatchment DMA-4 Property Value Name DMA-4 1 X-Coordinate 1500.000 ] Y-Coordinate 9200.000 j Description iTag Rain Gage Oceanside [Outlet BR-4 Area 0.11 [width 42 X Slope n i X Imperv 81.82 N-Imperv .012 N-Perv 0.05 I Dstore-lmperv .02 Dstore-Perv .1 ^ero-lmperv 25 1 Subarea Routing OUTLET Percent Routed 100 j Infiltration GREEN_AMPT 1 Groundwater NO Snow Pack UD Controls 0 Land Uses 0 Initial Buildup NONE Curb Length 0 Average surface slope [X] Subcatchment BR-1 Property Value Name BR-1 X-Coordinate -1500.000 Y-Coordinate 7200.000 Description Tag Rain Gage Oceanside Outlet POC-1 Area 0.046281 Width 10 X Slope ii) i X Imperv 0 N-Imperv 0.012 N-Perv 0.1 Dstore-lmperv .02 Dstore-Perv .1 ^ero-lmperv 25 Subarea Routing OUTLET Percent Routed 100 Infiltration GREEN_AMPT Groundwater NO Snow Pack LID Controls 1 Land Uses 0 Initial Buildup NONE Curb Length 0 Average surface slope (^) Subcatchment BR-2 ||Ei Property Value iName BR-2 : X-Coordinate -500.000 ; Y-Coordinate 7200.000 Description ;Tag Rain Gage Oceanside [Outlet POC-1 'Area 0.103053 jWidth 10 {X Slope 6 i ! X Imperv 0 N-Imperv .012 N-Perv 0.05 Dstore-lmperv .02 Dstore-Perv ,1 ^ero-lmperv 25 Subarea Routing OUTLET Percent Routed 100 1 Infiltration GREEN_AMPT ; Groundwater NO < Snow Pack •UD Controls 1 Land Uses 0 Initial Buildup NONE ; Curb Length 0 Average surface slope (%) Subcatchment BR-3 Property \ Value I Name BR-3 j X-Coordinate 500.000 1 Y-Coordinate 7200.000 [Description Tag i Rain Gage Oceanside [Outlet POC-1 [Area 0.079477 Width 10 X Slope |o X Imperv 0 N-Imperv 0.012 ! N-Perv 0.1 i Dstore-lmperv .02 Dstore-Perv .1 1 %Zeto-lmpefv 25 Subarea Routing OUTLET Percent Routed 100 Infiltration GREEN_AMPT Groundwater NO Snow Pack [UD Controls 1 • Land Uses 0 ; Initial Buildup NONE ! Curb Length 0 Average surface slope [%] Subcatchment BR-4 Property Value [Name BR-4 ! X-Coordinate 1500.000 Y-Coordinate 7200.000 Description iTag [Rain Gage Oceanside 1 Outlet POC-1 |Area 0.000391 Width 10 ; Si Slope 6 i j% Imperv 0 ;N-Imperv 0,012 1 N-Perv 0.1 Dstore-lmperv ,02 : Dstore-Perv .1 j SSZeto-lmperv 25 Subarea Routing OUTLET 1 Percent Routed 100 Infiltration GREEN_AMPT [Groundwater NO jSnow Pack LID Controls 1 Land Uses 0 1 Initial Buildup NONE i Curb Length 0 Average surface slope [X] Infiltration Editor Infiltration Method GREEN_AMPT Property i Value Suction Head 19 Conductivity 0.01875 Initial Deficit 0.3 Soil capillary suction head (inches or mm) EXPLANATION OF SELECTED VARIABLES Sub Catchment Areas: Please refer to the attached diagrams that indicate the DMA and Bio-Retention BMPs (BMP) sub areas modeled within the project site at both the pre and post developed conditions draining to the POC. Parameters for the pre- and post-developed models include soil type D as determined from the County of San Diego Hydrology Manual Soils Maps (attached at the end of this appendix). Suction head, conductivity and initial deficit corresponds to average values expected for these soils types, according to sources consulted, professional experience, and approximate values obtained by the interim Orange County modeling approach. TRWE selected infiltration values, such thatthe percentage of total precipitation that becomes runoff, is realistic for the soil types and slightly smaller than measured values for Southern California watersheds. Selection of a Kinematic Approach: As the continuous model is based on hourly rainfall, and the time of concentration for the pre-development and post-development conditions is significantly smaller than 60 minutes, precise routing ofthe flows through the impervious surfaces, the underdrain pipe system, and the discharge pipe was considered unnecessary. The truncation error of the precipitation into hourly steps is much more significant than the precise routing in a system where the time of concentration is much smaller than 1 hour. Sub-catchment BMP: The area of bio-retention must be equal to the area of the development tributary to the bioretention facility (area that drains into the bioretention, equal external area plus bio-retention itself). Five (5) decimal places were given regarding the areas ofthe bio-retention to insure that the area used by the program for the LID subroutine corresponds exactly with this tributary. UD Usage Editor Control Name Number of Replicate Units Area of Each Unit (sq ft or sq m) X of Subcatchment Occupied Top Width of Overland Flow Surface of Each Unit (ft or m) X Initially Saturated X of Impervious Area Treated UD Usage Editor Control Name Number of Replicate Units I I LID Occupies Full Subcatchment Area of Each Unit (sq ft or sq m) X of Subcatchment Occupied Top Width of Overland Flow Surface of Each Unit (ft or m) X Initially Saturated X of Impervious Area Treated 2016 100.0 0 100 3462 100,0 0 100 UD Usage Editor Control Name Number of Replicate Units Area of Each Unit (sq ft or sq m) X of Subcatchment Occupied Top Width of Overland Flow Surface of Each Unit (ft or m) X Initially Saturated X of Impervious Area Treated UD Usage Editor Control Name Number of Replicate Units Area of Each Unit (sq ft or sq m) X of Subcatchment Occupied Top Width of Overland Flow Surface of Each Unit (ft or m) X initially Saturated X of Impervious Area Treated 4489 100.0 0 0 100 17 99.8 0 0 100 UD Control Editor Control Name: LID Tjipe: 1S3 Bio-Retention Cell Process Layers: Surface [ Soil ] Storage ) Underdralnj Storage Depth (in, or mm) Vegetation Volume Fraction Surface Roughness (Mannings n) Surface Slope (percent) 11,158 0,05 0 0 UD Control Editor Control Name: LID Type: Bio-Retention Cett Process Layers: Surface J Soil | Storage [ Underdrain | Thickness (in, or mm) Porosity (volume fraction) Field Capacity (volume fraction) Wilting Point (volume fraction) Conductivity (in/hr or mm/hr) Conductivity Slope Suction Head (in, 01 mm) 24 0,2" 0,1 5"""'" 5 UD Control Editor Control Name: UD Type: Bio-Retention Cell Process Layers: Surface I Soil Storage | Underdrain I Height (in, or mm) Void Ratio (Voids / Solids) Conductivity (in/hr or mm/hr) Clogging Factor 6 0,67 0 0 Note: use a Conductivity of 0 if the LID unit has an impermeable bottom. UD Control Editor Control Name: LID Type: Bio-Retention Cell Process Layers: Surface j Sjiil J StoiageJ Underdrain Drain Coefficient (in/hr or mm/hr) Drain Exponent Drain Offset Height (in. or mm) 0,2581 0,5 0 Note: use a Drain Coefficient of 0 if the LID unit has no underdrain. UD Control Editor Control Name: LID Type: Bio-Retention Cell Process Layers; Surface I Soil | Stoiage [ Undeidiainj Stoiage Depth (in, or mm) Vegetation Volume Fraction Surface Roughness (Mannings n) Surface Slope (percent) 10,315 0,05 0,0 0,0 UD Control Editor Control Name: LID Type: Process Layers: Surface | Soil Bio-Retention Cell Storage I UnderdrainJ 6 0,G7 0 Clogging Factor 0 Height (in, or mm) Void Ratio (Voids / Solids) Conductivity (in/hr or mm/hr) Note: use a Conductivity of 0 if the LID unit has an impermeable bottom. UD Control Editor Control Name: LID Type: Bio-Retention Cell Process Layers: Suifacel Soil 1 Storage I Underdtainl THckness (in, or mm) Porosity (volume fraction) Field Capacity (volume fraction) Wilting Point (volume fraction) Conductivity (in/hr 01 mm/hr) Conductivity Slope Suction Head (in, or mm) 24 oT 02 0,1 5 5 UD Control Editor Control Name: LID Type: Process Layers: Bio-Retention Cell Surface | Soil [ StoiageJ Underdrain | _ 0,1 BB9 0,5 0 Drain Coefficient (in/hr or mm/hr) Drain Exponent Drain Offset Height (in, or mm) Note: use a Drain Coefficient of 0 if the UD unit has no underdrain. UD Control Editor li-i'^i.gil Control Name: UD Type: Process Layers: Bio-Retention Cell Surface | Soil J Storage | Undeidiainj as Stoiage Depth (in, 01 mm) Vegetation Volume Fraction Surface Roughness (Mannings n) Surface Slope (percent) 0,05 io 0,0 UD Control Editor Control Name: UD Type: mm Bio-Retention Cell Process Layers: Surface j Soil j Storage | Underdiainl Height G (in, or mm) Void Ratio f/oids / Solids) Conductivity (in/hr or mm/hr) Clogging Factor 0,67 0 Note: use a Conductivity of 0 if the LID unit has an impermeable bottom. UD Control Editor Control Name: UD Type: Bio-Retention Cell Process Layers: Surface} Soil [storage] Undeidiainj Thickness (in, 01 mm) Porosity (volume fraction) Field Capacity (volume fraction) Wilting Point (volume fraction) Conductivity (in/hi 01 mm/hr) Conductivity Slope Suction Head (in, 01 mm) 24 0,1 1,5 UD Control Editor Control Name: UD Type: Bio-Retention Cell Process Layers: Surface | Soil 1 Stoiage | Undeidiain Drain Coefficient (in/hr or mm/hr) Drain Exponent Drain Offset Height (in, or mm) 0,2945 0,5 0 Note: use a Drain Coefficient of 0 if the LID unit has no underdrain. UD Control Editor UD Control Editor Control Name: LID Type: Bio-Retention Cell Process Layers: ! Surface | Soil Storage 1 Underdrain | Height (in, or mm) Void Ratio (Voids / Solids) Conductivity (in/hr or mm/hr) Clogging Factor 6 0,67 0 0 Note: use a Conductivity of 0 if the LID unit has an impermeable bottom. Control Name: ^-^-^ a UD Type: | Bio-Retention Cell Process Layers: Surface j Soil j Storage Underdrain] Storage Depth 6 (in, 01 mm) Vegetation Volume 0,0 Fiaction Suiface Roughness 0,0 .... ™. (Mannings n) Suiface Slope 0,0 (percent) •— - - - UD Control Editor Control Name: UD Type: | Bio-Retention Cell y j Process Layers: j Surface f Soil j Storage 1 Underdralnj Thickness (in, or mm) 24 Porosity (volume fraction) 0,4 Field Capacity (volume fraction) Wilting Point (volume fraction) 0,1 Conductivity (in/hr or mm/hr) Too"' Conductivity Slope 5 Suction Head (in, or mm) iTs UD Control Editor Bio-Retention Cell Control Name: -'•••'^ LID Type: ' Process Layers: I Surface ( Soil | Storage j Underdrain |^ 11.0171 0,5 0 Drain Coefficient (in/hr or mm/hr) Drain Exponent Drain Offset Height (in, 01 mm) Note: use a Drain Coefficient of 0 if the LID unit has no undeidiain. LID Control Editor: Explanation of Significant Variables storage Depth: The storage depth variable within the SWMM model is representative of the storage volume provided beneath the engineered soil and mulch components ofthe bioretention facility. Porosity: A porosity value of 0.4 has been selected for the model. The amended soil is to be highly sandy in content in order to have a saturated hydraulic conductivity of approximately 5 in/hr. The Contech proprietary unit (LID 4) was modeled using the designated 100 in/hr rate. TRWE considers such a value (5 in/hr) to be slightly high; however, in order to comply with the HMP Permit, the value recommended by the Copermittees for the porosity of amended soil is 0.4, per Appendix A of the Final Hydromodification Management Plan by Brown & Caldwell, dated March 2011. Such porosity is equal to the porosity of the gravel per the same document. Void Ratio: The ratio of the void volume divided by the soil volume is directly related to porosity as n/(l-n). As the underdrain layer is composed of gravel, a porosity value of 0.4 has been selected (also per Appendix A ofthe Final HMP document), which results in a void ratio of 0.4/(1-0.4) = 0.67 for the gravel detention layer. Conductivity: Due to the natural soil existing on site, infiltration was a viable addition to the LID design. As the BMP is to be lined, the conductivity value was set to 0 to represent zero infiltration. C/oqq/nq factor: A clogging factor was not used (0 indicates that there is not clogging assumed within the model). The reason for this is related to the fairness of a comparison with the SDHM model and the HMP sizing tables: a clogging factor was not considered, and instead, a conservative value of infiltration was recommended. Drain (Flow) coefficient: The flow coefficient in the SWMM Model is the coefficient needed to transform the orifice equation into a general power law equation ofthe form: q = C{H-HDr (1) where q is the peak flow in in/hr, n is the exponent (typically 0.5 for orifice equation). Hp is the elevation of the centroid of the orifice in inches (assumed equal to the invert of the orifice for small orifices and in our design equal to 0) and H is the depth ofthe water in inches. The general orifice equation can be expressed as: ^ 4 5 144 12 ^ ' where Q is the peak flow in cfs, D is the diameter in inches, Cg is the typical discharge coefficient for orifices (0.61-0.63 for thin walls and around 0.75-0.8 for thick walls), g is the acceleration of gravity in ft/s^ and H and HD are defined above and are also used in inches in Equation (2). ATTACHMENTS Soils Map ATTACHMENT 9 Summary Files from the SWMM Model POST DEV EPA STORM WATER MANAGEMENT MODEL - VERSION 5.0 (Build 5.0.022) ********************************************************* NOTE: The summary statistics displayed in this report are based on results found at every computational time step, not just on results from each reporting time step. **************** Analysis Options **************** Flow Units CFS Process Models: Rainfall/Runoff YES Snowmelt NO Groundwater NO Flow Routing NO Water Quality NO Infiltration Method GREEN_AMPT Starting Date OCT-01-1951 00:00:00 Ending Date SEP-30-2008 23:00:00 Antecedent Dry Days 0.0 Report Time Step 01:00:00 Wet Time Step 00:15:00 Dry Time Step 04:00: 00 ************************** Volume Runoff Quantity Continuity acre-feet ************************** Total Precipitation 264.739 Evaporation Loss 44.408 Infiltration Loss 29.585 Surface Runoff 193.557 Final Surface Storage .... 0.009 Continuity Error (%) -1.065 Depth inches 674.360 113.120 75.361 493.040 0.022 ************************** Flow Routing Continuity ************************** Dry Weather Inflow Wet Weather Inflow Groundwater Inflow RDII Inflow External Inflow External Outflow Internal Outflow Storage Losses Initial Stored Volume .... Final Stored Volume Continuity Error (%) Volume acre-feet Volume 10"6 gal 0 000 0 000 193 557 63 073 0 000 0 000 0 000 0 000 0 000 0 000 193 557 63 073 0 000 0 000 0 000 0 000 0 000 0 000 0 000 0 000 0 000 Subcatchment Runoff Summary POST DEV Total Precip Total Runon Total Evap Total Infil Total Runoff Total Runoff Peak Runoff Runoff Coeff Subcatchment in in in in in 10-^6 gal CFS DMA-1 674 36 0 00 60 93 138 59 481 55 7 . 37 0.67 0 714 BR-1 674 36 5868 35 894 80 0 00 5671 61 7.13 0.70 0 867 DMA-2 674 36 0 00 74 87 44 63 560 75 20.51 1.61 0 832 BR-2 674 36 7329 56 925 41 0 00 7096 07 19.86 1. 73 0 887 DMA-3 674 36 0 00 70 46 89 24 519 92 32.80 2.76 0 771 BR-3 674 36 15196 49 1003 88 0 00 14919 25 32.20 2.85 0 940 DMA-4 674 36 0 00 62 90 85 79 535 61 1.60 0.13 0 794 BR-4 674 36 150684 44 1157 88 21 72 151023 98 1.50 0.13 0 998 DMA-BYPASS 674 36 0 00 73 09 0 00 610 82 2.28 0.17 0 906 *********************** LID Performance Summary *********************** Subcatchment LID Control Total Evap Infil Surface Inflow Loss Loss Outflow in in in in Drain Init. Final Pent. Outflow Storage Storage Error in in in BR-1 BR-2 BR-3 BR-4 LID-1 LID-2 LID-3 LID-4 6542.71 894.84 8003.92 925.44 15870.85 1003.92 151358.80 1153.30 0.00 113.15 5558.67 0.00 0.00 -0.37 0.00 385.72 6710.59 0.00 0.00 -0.22 0.00 3054.32 11865.56 0.00 0.00 -0.33 0.00 97198.58 54114.86 0.00 0.00 -0.73 Analysis begun on: Analysis ended on: Total elapsed time: Thu Sep 05 09:03:32 2013 Thu Sep 05 09:03:53 2013 00:00:21 PRE DEV EPA STORM WATER MANAGEMENT MODEL - VERSION 5.0 (Build 5.0.022) t******************************** t**************** NOTE: The summary statistics displayed in this report are based on results found at every computational time step, not just on results from each reporting time step. ********************************************************* **************** Analysis Options **************** Flow Units CFS Process Models: Rainfall/Runoff YES Snowmelt NO Groundwater NO Flow Routing NO Water Quality NO Infiltration Method GREEN_AMPT Starting Date OCT-17-1948 00:00:00 Ending Date OCT-17-2005 23:00:00 Antecedent Dry Days 0.0 Report Time Step 01:00:00 Wet Time Step 00:15:00 Dry Time Step 04 :00 :00 ************************** Runoff Quantity Continuity ************************** Total Precipitation Evaporation Loss Infiltration Loss Surface Runoff Final Surface Storage .... Continuity Error (%) ************************** Flow Routing Continuity ************************** Dry Weather Inflow Wet Weather Inflow Groundwater Inflow RDXI Inflow External Inflow External Outflow Internal Outflow Storage Losses Initial Stored Volume .... Final Stored Volume Continuity Error (%) Volume acre-feet Depth inches 255 . 239 650 .290 11 . 602 29 . 558 184 . 919 471 131 64 .297 163 813 0 .000 0 000 -2 .186 Volume Volume acre-feet 10"6 gal 0 .000 0 000 64 .297 20 952 0 .000 0 000 0 000 0 000 0 .000 0 000 64 297 20 952 0 .000 0 000 0 000 0 000 0 000 0 000 0 000 0 000 0 000 ***************************** Subcatchment Runoff Summary *********** t*********** PRE DEV Subcatchment DMA-1 Total Total Total Total Total Total Peak Runoff Precip Runon Evap Infil Runoff Runoff Runoff Coeff in in in in in 10^6 gal CFS 650.29 0.00 29.56 471.13 163.81 20. 95 5.33 0.252 Analysis begun on: Analysis ended on: Total elapsed time: Wed Sep 04 11:33:54 2013 Wed Sep 04 11:34:09 2013 00:00:15 ATTACHMENT 4 URBAN GREEN® BIOFILTRATION SPECIFICATIONS AND DETAILS iifiltration Producfs CONTECH' ENGINEERED SOLUTIONS UrbanGreen™ Stormwater Solutions from Contech ® It's simple to choose the right low impact development (LID) solution to achieve your runoff reduction goals with the Contech UrbonGreen Staircase. First, select the runoff reduction practices that are most appropriate for your site, paying particular attention to pretreatment needs. If the entire design storm cannot be retained, select a treatment best management practice (BMP) for the balance. Finally, select a detention system to address any outstanding downstream erosion. Surface Infiltration V VV Subsurface Infiltration Rainwater Harvesting Biofiltration 91 Filtration Hydrodynamic Separation © 2012 Contech Engineered Solutions LLC Detention Learn more about all of our stormwater technologies at www.ContechES.comMi^b<»-n^kX«,n UrbanGreen'" BioFilter Where stormwater runoff mitigotion goals can't be met through infiltration and rainwater harvesting, biofiltration can provide a high level of treatment and reduction of runoff volume due to soil saturation. The UrbanGreen BioFilter is a compact, versatile and reliable alternative to conventional designs. The UrbanGreen BioFilter soil media is optimized for pollutant removol hydraulic conductivity and plant vitality. Pollutants are primarily removed by filtration during a storm event and are transformed, assimilated and/or absorbed between runoff events by the microbiology within a soil ecosystem. The UrbanGreen BioFilter may also include one or more StormFilter cartridges which provide reliable pollutant removal for the portion of the design storm that exceeds the capacity of the biofilter bay. • Two well-known and accepted practices in one system - Biofiltration end media filtration • Proven removal capability - >95% solids removal (mean particle size 25 um) • Integrated bypass - eliminates cost of on additional bypass inlet. Offline designs also available. • Easy installation - Delivered on-site with all internal components installed, ready to lift end place • Multiple inline and offline sizes available to meet site-specific needs • Aesthetic landscape solutions will enhance the site ^ ,'> .! Inline and Inline XP units can be connected together to eliminote junction structure for a lower instolled cost Four Levels of Treatment in One - Inline Models Dry weather runoff and small storms are absorbed by the biofiltration media and returned to the atmosphere Medium size storms ore treated by biofiltration and released downstream Remaining water quality flow is treated with the StormFilter cartridges Peak events ore bypassed before reoching the treatment bays With multiple sizes and add-on filtration options, you can easily specify the right system for your site. Stormwater Management StormFilter'^ Cartridges; • Expand capacity to reduce system size • Extend life betvveen maintenance events • Optional infiltration rates from 5 to 1 00 in/ hr (125 to 2540 mm/hr) to meet approval standards. • Flow controlled outlet to maximize system longevity and performance. • Vertical drop into the system to collect debris without clogging inlet opening. • Optimized medio to meet standard guidelines for easy approval. • Infegmted bypass reduces cost by eliminoting downstream structures. Optional offline sizes without integrated bypass available. Learn more about the StormFilter at vv^ww. Contech ES. com/s f-0 t^ivi f i I f to Curb Inlet Capacity is the amount of flow that can enter through a curb inlet. This is based on local requirements and site conditions including depth of flow in the gutter, curb opening width, roadway and gutter design and location of the curb inlet (sag or on-grade). Integrated Bypass Capacity is the amount of flow that con be conveyed directly from the inlet tray to the outlet chomber without affecting the BioFilter or StormFilter components and without backing water up at the gutter. Inline - Model contains on integrated bypass that routes peak flows around the treatment components. Vault Size Rim to Invert Media Surface Area StormFilter Cartridges Treatment Capacity* Integrated Bypass Capacity Throat Length ' (in) ~ (in) (gpm) 1 (cfs) (cfs) (ft) Biofiltration Only 4X6 49 17 None 17.7 0.039 2 2.33 6X8 49 41 None 42.6 0.095 2 or 3.4 2.33 or 5.33 6X12 49 65 None 67.6 0.151 2 or 3.4 2.33 or 5.33 8X16 49 121 None 125.8 0.280 2 or 3.4 2.33 or 5.33 Biofiltration & Filtration 4X6 49 13 1-27" Toll 36 0.080 2 2.33 6X8 49 32 2-27" Toll 77 0.172 2 or 3.4 2.33 or 5.33 6X12 49 56 2-27" Tall 101 0.225 2 or 3.4 2.33 or 5.33 8X16 49 107 3-27" Toll 174 0.338 2 or 3.4 2.33 or 5.33 Inline model* NOTE: Non-standard/custom depths ond configurations available. Contact your local Contech representative for more information. Offline - Bypass Worn are routed externally. All depths are 42" Rim to Invert. Vault Media Surface Size Area Treatment Capacity* Throat Length (in) (gpm) (cfs) (ft) 4X4 16 16 0.036 4 4X6 24 24 0.054 6 or 4 4X8 32 32 0.071 8 or 4 6X6 36 36 0.080 6 4X12 48 48 0.107 12 or 4 6X8 48 48 0.107 8 or 6 6X10 60 60 0.134 10or6 6X12 72 72 0.161 12 or 6 7X13 91 91 0.203 13 or 7 'Cartridges are optional for these models Biofiltration Applications Combine biofiltration with subsurface infiltration to expond runoff reduction capacity. Create small drainage areas and use multiple units in parking lots. Add volume storage upstream; Slotted Droin"'' ond pervious pavers con extend the inlet copocity ond inlet location for challenging drainage areas. Multiple offline models are also available where separate high flow bypass drainage inlets may be required. Installation and Maintenance On-site planting ond activation included with every system Straightforward and simple to maintain - Clean biofiltration boy with simple landscape tools (rake and shovel) Extended maintenance interval - Biofiltration extends cartridge mointenonce intervols to 2 - 3 yeors No confined space entry required - Everything con be accessed from the surface Installation and Maintenance Manuals available www.ContechES.com/biof i If" An elementary school utilizes the UrbanGreen BioFilter in a busy parking lot Next Steps Read Biofilfrotion Des/gn, Operofion ond A/la/ntenonce Cons/'deraf/ons available at vAvw.ContechES.com/U.^^b^>.n^^^^v We're alv^oys available to make your job easier Search for your local rep at www.Con1echES.com. While you're there, be sure to check out our upcoming seminar schedule or request an in-house technical presentation. If you ore ready to begin a project, you con find the UrbanGreen BioFilter specification, standard details, design guide and more on our website at www.ContechES.com/biO-filf"^*^ To use the Land Value Calculator, visit: www.ContechES.com/l\/t (Please scroll to the bottom right to download the Land Value Calculator) To use the Des/gn Your Own Detention System tool, visit: www.ContechES.comM x^odis To use the Rain Water Harvesting Runoff Reduction Calculator tool, visit: www. ContechES.com/*^ w W -1 11 u, I ccf-0 >^ C0NTECH ENGINEERED SOLUTIONS ©2012 Contech Engineered Solutions LLC 800 338.1122 wwv/.ContechES.com All Rights Reserved. Printed in the USA NOTHING IN THIS CATALOG SHOULD BE CONSTRUED AS AN EXPRESSED W/ARRANTY OR AN IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. SEE THE CONTECH STANDARD CONDITIONS OF SALE (VIEWABLE AT WWWCONTECHES.COM/COS) FOR MORE INFORMATION. Get Sociol With UsI 11 We print our brochures entirely on Forest Stewordship Council certified paper. FSC certification ensures that the paper in our brochures contain fiber from well- managed and responsibly horvested forests that meet strict environmental and socioeconomic standards. UGBF Brochure 1/12 SM URBANGREEN TM 0i UrbanGreen'" BioFilter Design, Operation and Performance C0NTECH ENGINEERED SOLUTIONS BioFilter UrbanGreen'" BioFilter Overview The UrbanGreen'" BioFilter is an enhanced biofiltration system that combines nature's ability to treat stormwater runoff with the proven performance capabilities of cartridge-based media filtration. This combination of biological and engineered media filtration create the perfect balance for the removal of common pollutants found in stormwater runoff. Although the UrbanGreen BioFilter will complement any site, it was specifically developed as a component for low impact development (LID) sites. LID is an approach to stormwater management, emphasizing the use of small, decentralized management practices to treat rainfall close to its source and facilitate infiltration back into the ground. The goal of LID is to maintain the predevelopment hydrology and to lower the overal environmental impact footprint of the site. Common LID practices include biofiltration, bioretention and media filtration. The UrbanGreen BioFilter incorporates all three of these processes into one system to maximize the pollutant removal capabilities. Furthermore, the UrbanGreen BioFilter is specifically designed to treat small catchment areas and can easily be combined with underground infiltration, so runoff can be treated and infiltrated close to where the rain falls. This decentralized approach to managing stormwater is a core principle of LID. Basic Operation The UrbanGreen BioFilter is constructed in a curb inlet configuration and designed to treat runoff from roadways, parking lots, roof tops, and other runoff generating surfaces. The basic operation and components of the UrbanGreen BioFilter are illustrated in Figure 1. As illustrated, initial runoff enters the system and is directed by the inlet weir into the bioretention bay. A variety of complex treatment processes including physical, chemical, and biological activities occur as stormwater infiltrates through the engineered soil mixture and interfaces with the root system of the tree or other vegetation. The specific components of the engineered soil mixture were selected to provide high pollutant removal and permeability while maintaining sufficient moisture content for plant growth. After infiltrating through the engineered soil mixture stormwater exits the bioretention bay via the bioretention bay underdrain which directs the treated stormwater to the outlet chamber The UrbanGreen BioFilter employs two distinct treatment components. The first is the bioretention component as described above. The second is an optional media filtration component. When the bioretention bay reaches its treatment capacity, runoff begins to flow through the cartridge bay inlet located at a set elevation above the surface of the engineered soil mixture. This runoff is treated by Stormwater Management StormFilter'* (StormFilter) media cartridges prior to discharging into the outlet chamber StormFilter media cartridges are among the most thoroughly tested and proven stormwater treatment devices and can be designed with a variety of media types including CSF leaf compost, Periite and ZPG (a blend of Zeolite, Periite and Granular Activated Carbon) to target the specific pollutants of concern. More information on the operation and performance of the StormFilter media cartridge can be found in the StormFilter Configuration Guide available at www.ContechES.com. The two stage treatment process of the UrbanGreen BioFilter ensures that the initial runoff from small urban catchments, which commonly carries the highest pollutant concentrations, is treated via bioretention. Higher flows are treated by StormFilter media cartridges. Consequently, unlike similar manufactured tree box filters, the bioretention bay is not inundated with a higher degree of runoff or pollution than it can reasonably handle without causing frequent bypass or maintenance issues. NATIVE VEGETATION (numerous types available) INLET WEIR/ INTERNAL BYPASS BIOFILTRATION (engineered soi CURB INLET (other configurations available OUTLET BIOFILTRATION BAY UNDERDRAIN Figure 1: Basic Operation & Components ofthe Inline unit with cartridges The UrbanGreen BioFilter is designed with an optional internal bypass to allow runoff exceeding the capacity of both the bioretention bay and the media cartridges to discharge directly into the outlet chamber. This unique feature of the UrbanGreen BioFilter protects against high flow washout of previously captured pollutants and reduces overall project costs by eliminating the need for external bypass structures. Treated and bypassed flows are joined in the outlet bay of the system where they can then be directed into a detention or retention system as site conditions and regulations dictate. If infiltration is feasible based on soil conditions, Contechrecommends that the UrbanGreen BioFilter be combined with subsurface infiltration BMPs such as the ChamberMaxx'" or perforated CMP system (more information available at www.ContechES.com.) to facilitate groundwater recharge and reduce runoff from the site. www.ContechES.com/biofilter Design Process The UrbanGreen BioFilter provides a variety of stormwater management and development benefits including a high level of removal of the primary pollutants of concern, unconstrained placement of the system on the site, improved aesthetics, improved air quality and potential LEED credits. Another benefit is the simple sizing process for this technology. The UrbanGreen BioFilter is available in multiple sizes and configurations to allow for maximum efficiency. If the system is a combination BioFilter and Media Filter, the total treatment capacity is the aggregate of the treatment capacities of the bioretention bay and StormFilter media cartridges. The design infiltration rate of the bioretention bay is controlled by the initial media permeability and a flow control orifice. Although the infiltration rate may vary in different jurisdictions, 100 in/ hr (approximately 1 gpm per square foot) of surface area is the typical design infiltration rate. The surface of the engineered soil mixture varies with model size for ultimate specification flexibility. Testing has shown that the engineered soil mixture in the bioretention bay can infiltrate at a rate of up to 500 in/hr at the design driving head of 6 inches, however an outlet flow control limits the rate so significant pollutant loads can accumulate before the media drops below the design infiltration rate. Using an outlet flow control to control infiltration rates rather than the media itself allows soil with a higher void volume to be used. This substantially decreases the frequency of maintenance because there is more storage volume for captured pollutants within the soil media. It also improves performance by reducing velocities in the pore spaces within the media. The treatment capacity of the media cartridge portion of the UrbanGreen BioFilter is based on treating runoff at a rate of 2 gpm per square foot of cartndge surface area. Like the soil mixture, the media cartridges are designed with a flow control, so flow through each cartridge is restricted to the design rate. This feature improves both the performance and longevity of the cartridges. Local regulations will typically determine how much flow needs to be treated. Many regulatory agencies specify a water quality "design storm" such as a 6-month or 1-year return period storm event. Refer to local guidelines for the calculation of required design storm. Once the treatment flow rate has been determined, simply divide that amount by the total treatment capacity of the UrbanGreen BioFilter to determine the number of units needed. When placing the system on site, there are few constraints on the location of the UrbanGreen BioFilter system (unlike similar systems that cannot be placed at the low point of a parking lot or require unidirectional flow along a curb face in order to function). Once a location for the UrbanGreen BioFilter has been determined, compare the anticipated peak conveyance flow with the bypass capacity to ensure that the system has sufficient capacity to handle these higher flows. Two hydraulic controls impact the bypass capacity of the UrbanGreen BioFilter The throat opening controls the hydraulic capacity as a function of the opening width, allowable top width, gutter cross slope, manning's "n," and other relative factors. State and local jurisdictions typically provide inlet design guidelines for flow hydraulics. (If this information is not available, refer to the FHWA HEC 12 Drainage of Highway Pavements, 1984. http://www.fhwa.dot.gov/engineering/hydraulics/pubs/hec/ hec12.pdf) The second hydraulic control is the internal bypass weir. The crest elevation is 7 inches below the grade break point of the curb opening inlet at the face of curb and has a weir length that varies with the model type and size. It is a sharp crested weir. The capacity of the bypass weir is calculated using the discharge equation, Q = cLH^^, with a c of 3.3. For example, with 7 inches of driving head, a discharge coefficient of 3.3, and a woir length of 2'4", the peak bypass capacity is 3.4 cfs. This is given the conservative assumption that there is no flow through the treatment system itself in the event that proper maintenance practices are not observed. The UrbanGreen BioFilter has been hydraulically tested and evaluated for scour at peak flows with results showing that no scour was present in the system. These observations indicate that the system could handle higher flows without compromising performance. The maximum bypass capacity ofthe UrbanGreen BioFilter is therefore a function of the maximum allowable depth of flow at the curb face as defined by the governing jurisdiction. This substantial internal bypass capacity is a key advantage of the UrbanGreen BioFilter as it eliminates the need for additional external structures. However, if the bypass capacity of the UrbanGreen BioFilter is less than the anticipated peak conveyance flow rate, then an external bypass may be used. www.ContechES.com/biofilter Performance Testing As part of the development of the UrbanGreen BioFilter, several soil mixtures were subject to large-scale column tests in order to identify a combination of soil components that offered the best combination of porosity, conductivity, treatment capacity, water retention capacity and performance (de Ridder, 11/17/08). Testing was conducted using an apparatus that simulated a 1.8- ft^ section of a full-scale UrbanGreen BioFilter soil bed. Experiments included: 1. Retention - water retention characteristics 2. Head Loss - stage discharge relationships 3. Sediment Removal - assessment of sediment removal capabilities 4. Nutrient removal - Phosphorous removal capabilities Two mixtures were identified for use with the UrbanGreen BioFilter. The West Coast 4P Blend consists of a specific mixture of sand, processed leaf compost, porous aggregate and special additives. The East Coast 2P Blend consists of natural sand and sufficient organic matter for plant growth. With respect to water retention, a fresh sample of the chosen soil mixture demonstrated a 1-hr specific retention (ratio of volume of water retained against gravity in 1 -hr to the total volume of soil) of 0.32. These values were similar to those observed for soil mixtures with particle size distributions that were much finer than the chosen soil mixture. The biofiltration component of the UrbanGreen BioFilter treats stormwater at rates up to 100 in/hr. The high conductivity of the chosen soil mixture provides the desired hydraulic loading rate at a much lower driving head (Figure 2), This suggests that the soil mix allows the system to operate at design hydraulic loading rates for an extended period of time despite continuous interstitial sediment accumulation. Sediment removal characteristics of the chosen soil mix were very high. Greater than 90% removal was observed at the design operating rate of 100 in/hr using the Sil-Co-Sil 106 sediment removal testing standard (SG = 2,65, dSO = 25-um), More information on the evaluation of the UrbanGreen BioFilter is available upon request. JZ o c X3 (D 0) X ICQ 150 200 250 Hydraulic Loading Rate (in/hr) Figure 2: Hydraulic Loading Characteristics ofthe UrbanGreen BioFilter CONTECH ENGINEERED SOLUTIONS ©2012 CONTECH ENGIIJEERED SOLUTIONS, LLC, 600-338-1122 www.ContechES.com All Rights Reserved. Printed in the USA. Contech Engineered Solutions LLC, provides site solutions for the civii engineering industry. Confech's portfolio includes bridges, drainage, sanitor\' sewer, stormwater ond earth stabilization products. For information on other Contech division offerings, visit ContechES.com or call 800.338.1122 The product(s) described may be protected by one or more ofthe following US patents: 5,322,629; 5,624,576; 5,707,527; 5,759,415; 5,788,848; 5,985,157; 6,027,639; 6,350,374; 6,406,218; 6,641,720; 6,511,595; 6,649,048; 6,991,114; 6,998,038; 7,186,058, 7,296,692; 7,297,266; related foreign patents or other potents pending. The Stormwater Monogement Stormpilter, MPS and CDS are trademarks, registered trademarks, or licensed trademartcs of Contech Engineered Solutions LLC LEED is a registered trademark ofthe U.S. Green Building Council. Support • Drawings and specifications are available at contechstormv*'ater.com. • Sife-specitic ciesign support is available from our engineers. NOTHING IN THIS CATALOG SHOULD BE CONSTRUED AS AN EXPRESSED WARRANTY OR AN IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. SEE THE CONTECH STANDARD CONDITIONS OF SALE (VIEWABLE AT VWW.CONTECHES.COM/COS) FOR MORE INFORMATION. ub_bf_design guide 06/12 ENGINEERED SOLUTIONS rnnruiMViMi^iuc wvcnvicvv Performance ofthe UrbanGreen™ BioFilter with 2P Biomedia for the Removal of Suspended Solids, Total Phosphorus and Heavy Metals from Stormwater Runoff Introduction The effectiveness of biofiltration systems as a means of treating urban runoff is well documented. A growing body of biofilter performance data demonstrates that flow through biofiltration systems consistently remove high levels of many common stormwater pollutants. A biofilter monitored for several years at the University of New Hampshire Stormwater Center achieved 87% Total Suspended Solids(TSS) removal, 99% Total Petroleum Hydrocarbons-Diesel Range(TPH-D) removal, 68% Total Zinc removal, 34% Total Phosphorous(TP) removal and has reduced average annual peak flows by 79% (UNH, 2009). A University of Virginia biofilter study reported equally impressive removal efficiencies, 86%TSS, 90% TP, 97% COD and 67% Oil and Grease (Yu et al, 1999). Biofiltration combines physical filtration and reactive processes with biological processes to maximize the removal of stormwater pollutants. Biofiltration systems are typically composed of a soil media that includes an organic component such as compost, peat or mulch as well as native vegetation, all of which aid in pollutant removal. Water is introduced to the surface of the system where it ponds and then filters through the soil media. The soil media filters particulate pollutants both at the surface as well as within the media bed. The addition of an organic component such as compost or peat to the media allows the system to sequester dissolved pollutants through reactive processes such as cation exchange. The inclusion of vegetation also adds a number of benefits to the system including nutrient uptake, increased evapotranspiration, promotion of beneficial bacterial growth, improved aesthetics and increased hydraulic conductivity. While much of the pollutant load is removed via filtration, employment of multiple unit processes within the system enhances performance in comparison with basic media filters (Clar et al, 2004). UrbanGreen BioFilter The UrbanGreen™ BioFilter is a high capacity tree well style biofilter housed within a concrete vault. The biofilter is modeled after conventional biofilter designs with a few notable enhancements to maximize performance, hydraulic conductivity and longevity. The engineered biomedia is comprised of an optimized blend of sand and peat granules. The consistent, engineered media blend ensures that each unit performs as intended, and eliminates the complications and uncertainty caused by trying to blend a biofiltration media to specification onsite. The UrbanGreen BioFilter utilizes an internal bypass to convey extreme flows, so when desirable the system may be placed online without the need for an external bypass structure. The UrbanGreen BioFilter has a design saturated hydraulic conductivity (infiltration rate) of 100 in/hr and a media bed depth of 24 inches. An outlet flow control limits the infiltration rate so significant pollutant loads can accumulate before the media drops below the design infiltration rate and maintenance is required. Unregulated, 2P biomedia has been shown to have a saturated hydraulic conductivity exceeding 300 in/hr. Using an outlet flow control rather than the media to control infiltration rates allows soil with a higher void volume to be used and makes system performance much more consistent over time. This substantially decreases the frequency of maintenance because there is more storage volume for captured pollutants within the biomedia. Performance is also improved by reducing velocities in the pore spaces within the biomedia (Contech 2011). PERFORMANCE OVERVIEW The UrbanGreen BioFilter utilizes biomedia with a high hydraulic conductivity and operates as a depth filter rather than a surface filter, which is the principal of operation for lower infiltration rate biofilters. A recent review of the available performance data on similar high rate biofiltration systems concluded that "Effluent concentrations achieved in the full-scale studies were generally equal to or lower than median effluent concentrations for the biofilter and media filter classes of BMPs reported in the International Stormwater BMP Database" (Lenth et al, 2010). 2P biomedia The UrbanGreen BioFilter utilizes a 24 inch deep bed of 2P biomedia to treat urban runoff. 2P biomedia (DSO = 4 mm) consists of an engineered blend of coarse sand and peat granules. This unique biomedia was created specifically to achieve high levels of pollutant removal while maintaining a high infiltration rate while maximizing longevity and minimizing the potential leaching of nutrients from the organic content. For most applications 2P biomedia has a design infiltration rate of 100 in/hr corresponding to 1.04 gallons per minute per square foot of biomedia surface area. Suspended Solids Removal To evaluate the ability of the UrbanGreen Biofilter to sequester suspended solids with 2P biomedia at the design infiltration rate of 100 in/hr a series of column scale trials was initiated using Sil-Co-Sil® 106 as the surrogate source of suspended solids. Sil-Co-Sil* 105 is a fine gradation of silica particles that has been specified by a number of prominent regulatory agencies, including the Washington Department of Ecology (WADOE), for use in evaluating stormwater management practices for solids retention. As depicted in Figure 1, Sil-Co-Sil® 106 has a median particle size (dSO) of ~25 nm. 10 100 Particle Size (nm) Figure 1. Particle Size Distribution forSil-Co-Sil 106 Silica Gradation 1000 To assess the ability of the UrbanGreen Biofilter to retain Sil-Co-Sil® 106 at an infiltration rate of 100 in/hr with a 24 inch deep bed of 2P biomedia, seven performance trials were conducted at influent concentrations between 0 and 300 mg/L. The 2P biomedia showed excellent retention of solids in all trials. Based on the regression of EMC method the 2P biomedia removed 93% of Sil-Co-Sil® 106 during the seven trials, the results of which are plotted in Figure 2 (Ma and Tracy 2012a). ©2012 Contech Engineered Solutions, LLC www.ContechES.com Page 2 of 7 PERFORMANCE OVERVIEW 150 5 100 50 2P Biomedia 24 inch S lOOinhr • Raw data —LOWMPS'O HiehM95°. y-0.07x +0.08 R'-0.99 400 Inllufnt SSC, mz L Figure 2. Comparison of influent and effluent Sil-Co-Sil 106 concentrations for seven 2P biomedia performance trials at 100 in/hr To demonstrate the ability of 2P biomedia to remove Sil-Co-Sil® 106 at higher infiltration rates, a second set of performance trials was conducted at a design infiltration rate of 200 in/hr. Aside from doubling the design infiltration rate, all test conditions were kept consistent with the aforementioned Sil-Co-Sil® 106 trials conducted at 100 in/hr. Seven trials were conducted at influent concentrations between 2 and 310 mg/L. Based on the regression of EMC method, a 24 inch deep bed of 2P media removed 89% of Sil-Co-Sil® 106 at a design infiltration rate of 200 in/hr. The results of these trials are plotted in Figure 3. 200 1 150 y. 100 2P Biomedia 24 inch 2 200 in hr • Raw data —Lower 95"e J y-0.111 +10J R«-0^ 200 Influent SSC, mg L 400 Figure 3. Comparison of influent and effluent Sil-Co-Sil* 106 concentrations for seven 2P biomedia performance trials at 200 in/hr ©2012 Contech Engineered Solutions, LLC www.Contech ES .com Page 3 of 7 PERFORMANCE OVERVIEW In addition to the Sil-Co-Sil® 106 trials, additional testing was carried out to assess the performance of 2P biomedia for a wider gradation of stormwater solids and total phosphorus. Actual stormwater solids were screened to remove all particles larger than SOOum and then added to source water at an average influent concentration of 156 mg/L. Hourly sampling was conducted over multiple days resulting in a dataset spanning 30 hours of system operation. The 2P biomedia demonstrated excellent retention of solids throughout the test period. The average effluent suspended solids concentration during the study was 2 mg/L. As shown in Figure 4, the average removal of suspended solids during this study was 99%. 100 80 60 u 40 20 Average removal = 99% Average influent SSC = 1 56 mg/L 10 15 20 25 30 Testing time, hrs Figure 4. Removal of stormwater solids less than SOO ^m by 2P biomedia at a a design infiltration rate of 100 in/hr Phosphorus Removal In order to assess the ability of 2P biomedia to remove phosphorus from stormwater runoff influent and effluent samples were also collected and analyzed for total phosphorus. Stormwater solids known to contain phosphorous were screened to remove all particles larger than SOOum and then added to source water at an average solids concentration of 156 mg/L. All samples were sent to an independent third party analytical laboratory for total phosphorus analysis. The resulting average influent total phosphorus (TP) concentration was 0.128 mg/L. Hourly sampling conducted over multiple days and encompassing 30 hours of system operation demonstrated that the 2P biomedia removed on average 83% of the TP. The average effluent TP concentration for the study was 0.021 mg/L, very close to the detection limit of 0.02 mg/L. The results of these trials are plotted in Figure 5 (Ma and Tracy 2012b). ©2012 Contech Engineered Solutions, LLC www.ContechES.com Page 4 of 7 PERFORMANCE OVERVIEW 100 95 - 90 2 85 a 80 75 70 Average influent TP = 0.128 mg/L Average effluent TP = 0.021 nig/I.. Non-delect limit = 0.02 mg/L Average Removal = 83% 10 15 20 30 Testing time, hrs Figure 5. Removal of total phosphorus over time by 2P biomedia at a design infiltration rate of 100 in/hr Heavy Metals Removal Heavy metals such as zinc, copper and lead are commonly transported by stormwater runoff and pose a serious threat to receiving waters. Since heavy metals exist in both particulate and dissolved forms, achieving high levels of metals removal can be challenging for BMPs that only retain particulate pollutants. Having already demonstrated the ability of the UrbanGreen BioFilter to remove a substantial fraction of the particulate pollutants, a series of laboratory trials was conducted to evaluate the effectiveness of the system for removing dissolved metals. Nine two-day long laboratory trials were conducted to assess the removal of dissolved zinc, copper and lead from simulated stormwater with the UrbanGreen BioFilter. All trials were conducted in a column test apparatus with 24 inches of 2P biomedia at a hydraulic loading rate of lOOin/hr. Three trials were conducted for each of the different metals at varying target influent concentrations (Table 1). Each trial consisted of two 6 hour periods of system operation that spanned two consecutive workdays. During operation a dissolved solution ofthe target metal calibrated to produce the target influent concentration was constantly fed to the test system at a hydraulic loading rate of lOOin/hr. Hourly influent and effluent samples were collected during all trials and sent for analysis at Apex Labs, an independent laboratory in Tigard, Oregon. (Ma and Tracey 2012c). Run# Target Influent ppb Target Influent ppb Target Influent ppb 1 Dissolved Cu (CuCl2-2H20) 20 Dissolved Zn (ZnClz) 100 Dissolved Pb (PbClz) 20 2 Dissolved Cu (CuCl2-2H20) 50 Dissolved Zn (ZnClz) 200 Dissolved Pb (PbClz) 50 3 Dissolved Cu (CuCl2-2H20) 100 Dissolved Zn (ZnClz) 400 Dissolved Pb (PbClz) 100 Table 1. Target influent Concentration for UrbanGreen BioFilter Dissolved Metals Removal Trials. Results ofthe dissolved metals trials were highly favorable. The UrbanGreen BioFilter removed 95% of dissolved zinc based on linear regression of all trials. The system removed 84% of dissolved copper based on linear regression of all trials. Removal of dissolved lead was more modest with the system achieving an average removal of 36% for all trials. Additional research is needed to asses why removal of dissolved lead was not as high as that achieved for zinc and copper, but it is possible low influent concentrations played a role in the lower performance. The average influent concentration for all dissolved lead trials was only 36.7 ppb as a result of many of the trials having actual influent ©2012 Contech Engineered Solutions, LLC www.ContechES.com Page 5 of 7 PERFORMANCE OVERVIEW concentrations well below the intended target. More importantly, the system still achieved positive removal of dissolved lead despite the low influent concentrations. All results have been summarized and included in Table 2 below. Pollutant Percent Removal Diss. Zn 95 Diss. Cu 84 Diss. Pb 36 Table 2. Results of UrbanGreen Biofilter Dissolved Metals Removal Laboratory Trials with a 24 Inch bed of 2P Biomedia at a Hydraulic Rate of 100!n/hr. Overall, the UrbanGreen BioFilter showed excellent removal of dissolved metals across varying influent concentrations. Retention of dissolved metals in addition to the capture of particulate bound metals will result in a reduction of the total metals load transported by stormwater runoff that exceeds the capability of systems only targeting particulate metals. Conclusions Multiple studies have demonstrated that a 24 inch deep bed of 2P biomedia operated at a controlled saturated hydraulic conductivity (infiltration rate) of 100 in/hr is highly effective at removing suspended solids, total phosphorus and dissolved metals from stormwater runoff. Over the course of seven trials at a design infiltration rate of 100 in/hr with influent concentrations ranging from 0-300 mg/L the 2P biomedia removed 93% of Sil-Co-Sil* 106. During a second set of seven trials conducted at a design infiltration rate of 200 in/hr with influent concentrations ranging from 2-310 mg/L the 2P biomedia removed 89% of Sil-Co-Sil® 106. A trial spanning 30 hours of system operation revealed that the 2P biomedia removed on average 99% of stormwater solids and reduced effluent solids concentrations to 2mg/L on average. During the same study the 2P biomedia retained on average 83% of the total phosphorus load. The average effluent TP concentration during the 30 hours of sampling was 0.021mg/L. Three laboratory trials spanning two days each showed that a 24 inch deep bed of 2P biomedia operated at a controlled infiltration rate of lOOin/hr was able to remove 95% of dissolved zinc based on linear regression. Three additional laboratory trials demonstrated that a 24 inch deep bed of 2P biomedia operated at a controlled infiltration rate of lOOin/hr was able to remove 84% of dissolved copper based on linear regression. Three laboratory trials spanning two days each showed that a 24 inch deep bed of 2P biomedia operated at a controlled infiltration rate of lOOin/hr was able to reduce dissolved lead concentrations by 36% on average. Hydraulic testing confirmed that the engineered 2P biomedia blend has an initial hydraulic conductivity exceeding 300 in/hr. Performance trials demonstrated the ability of 2P biomedia to remove 89% of Sil- Co-Sil 106 at a design infiltration rate of 200 in/hr, making 2P media an optimal choice for high rate biofiltration applications. Collectively, these results demonstrate that the UrbanGreen Biofilter with 2P media represents a highly effective means of treating urban runoff. ©2012 Contech Engineered Solutions, LLC Page 6 of 7 www.ContechES.com PERFORMANCE OVERVIEW References Clar, M.L., Barfield, B. J., and O'Connor, T. P. (2004). Stormwater Best Management Practice Design Guide Volume 2 Vegetated Biofilters. Cincinatti, OH, USEPA. Available Online: http://www.epa.gov/nrmrl/pubs/600r04121/600r04121a.pdf CONTECH Engineered Solutions. (2011). Managing Urban Runoff with the UrbanGreen BioFilter. Scarborough, ME. Author. Ma, J. and Tracy, K. (2012a). Removal of Sil-Co-Sil 106 by 2P Biomedia (DSO = 4 mm) 100 in/hr and 24 inch Media Column Testing. Portland, OR. Author. Ma, J. and Tracy, K (2012b). TP Removal Using UG 2P Biomedia. Portland, OR. Author Ma, J. And Tracy, K. (2012c). Removal of Dissolved Metals and Nutrients by 2P Biomedia. Portland, OR. Author. Lenth, J., Dugopolski, R., Quigley, M., Poresky, A., and Leisenring, M. (2010). Filterra Bioretention Systems: Technical Basis for High Flow Rate Treatment and Evaluation of Stormwater Quality Performance. Seattle, WA. Author. University of New Hampshire Stormwater Center. (2009). 2009 Biannual Report. Durham, NH: Author. Available Online: http://www.unh.edu/unhsc/sites/unh.edu.unhsc/files/pubs specs info/2009 unhsc report.pdf Yu, S.L., X. Zhang, A.Earles, and M. Sievers, (1999). "Field Testing of Ultra-urban BMPs". Proceedings of the 26th Annual Water Resources Planning and Management Conference, E. Wilson (Ed.), ASCE, June 6- 9, 1999, Tempe AZ. ©2012 Contech Engineered Solutions, LLC Page 7 of 7 www.ContechES.com CONTECH ENGINEERED SOLUTIONS URBANGREEN TM BioFilter Maintenance Manual BioFilter UrbanGreen BioFilter™ Inspection and Maintenance The UrbanGreen™ BioFilter should be inspected at regular intervals and maintained when necessary to ensure optimum performance. The rate at which the system collects pollutants will depend more heavily on site activities than the size of the unit (i.e. unstable soils or heavy winter sanding will cause the system to fill more quickly but regular sweeping will slow accumulation). Maintenance of the UrbanGreen BioFilter should be performed by a qualified professional who has experience with maintenance of stormwater management systems. For more information, please contact CONTECH at 800.338.1122 or info@contech-cpi.com. Inspection and Routine Maintenance Inspection is the key to effective maintenance. Inspect annually unless local regulations or site conditions require more frequent inspection. Routine maintenance, defined as trash and debris removal and general upkeep, should be performed during each inspection if necessary First record the height, width and condition of the tree. A sample log is provided. Once these recordings have been taken, the tree grate should be removed to observe the bioretention bay Any trash and debris that has collected here should be removed and disposed of appropriately. As with all media filtration systems, captured pollutants and sediments will accumulate on the surface of the engineered soil mixture over time, reducing the treatment capacity of the system. If captured pollutants are observed to have occluded the media surface, or if standing water is present in the biofiltration bay during dry periods, then maintenance of the top layer of soil mixture is required. Studies have shown that the majority of all captured pollutants reside in the top 2-3 inches of soil and therefore it is likely that only this layer needs to be replaced. (California Stormwater Quality Association (CASQA), New Development and Redevelopment Handbook, January 2003). Replacement soil is available from CONTECH. Please note that when replacing the engineered soil mixture, the energy dissipation rocks which protect the inlet from scour should be collected and set aside for use with the new soil. Once the new soil has been installed, the energy dissipation rocks should be placed back at the inlet. Once the bioretention bay has been inspected and maintenance procedures completed, the tree grate placed should be put securely back in place. As part of the standard terms of system purchase, CONTECH will supply routine maintenance services as described herein within approximately 1 year of system activation. Associated maintenance log records will be made available to the owner upon request. Inspection and maintenance of the media cartridge bay are also critical to the overall performance of the system. Inspection should be performed at the same time as inspection of the bioretention bay Remove the cover over the media cartridge bay and observe the accumulated pollutants within the chamber If more than three inches of sediment is found on the chamber floor or on the tops of the cartridges, then cartridge replacement should be performed. Additionally, if standing water resides in the chamber for greater than twenty-four hours after a storm event, then cartridge replacement should be performed. Depending on site and climatic conditions, maintenance frequency of the media cartridges should range from 3 to 5 years. Instructions for cartridge replacement are provided in the Non-Routine Maintenance section below. All observations from inspection of the media cartridge bay should be recorded in the maintenance log. Non-Routine Maintenance Non-routine maintenance is defined as clean-out of the media cartridge bay and replacement of cartridges. Replacement cartridges can be ordered by contacting CONTECH at 800.338.1122. The first step in the clean-out of the media cartridge bay is to remove the sediment and debris that has collected in this chamber. A vacuum truck or manual operation can be used for this procedure. Once the sediment and debris has been removed, the existing cartridges should be removed from the system. Cartridges are connected to the underdrain manifold by a simple quarter-turn connection and are easily disconnected. Once the cartridges are removed from the vault, any remaining sediment and/or debris should be cleaned out. The final step in the cartridge replacement process is to install the replacement cartridges. Replacement cartridges should be installed securely to the quarter-turn connection system and the cover placed securely back over the media cartridge bay General Maintenance Notes All OSHA standards for health and safety should be followed at all times when inspecting or maintaining the UrbanGreen BioFilter. Furthermore, disposal of pollutants removed from the UrbanGreen BioFilter should be performed in accordance with all regulatory requirements. UrbanGreen BioFilter Inspection & Maintenance Log Project Name: Location: Date of Installation: UrbanGreen BioFilter Inspection & Maintenance Log Project Name: Walmart Location: Anywhere, USA Date of Installation: 10/01/05 Date Tree Height/Width/ Condition Bioretention Bay Routine Maintenance Performed Media Cartridge Bay Observations Media Cartridge Bay Maintenance Performed 12/01/06 36"/247good condition Removed debris from chamber Slight Sediment layer on floor None required 12/01/07 38"/28"/goocl condition Removed debris /replaced soil top layer 1" of sediment on floor None required 12/01/08 427327needs irrigation Removed debris from chamber 1 1/2" of sediment on floor None required 12/01/09 477387good condition Removed debris from chamber 2" of sediment on floor None required 12/01/10 507397good condition Removed debris /replaced soil top laye 2 1/4" of sediment on floor None required 12/01/11 52 742 7needs irngation Removed debris from chamber 2 1/2" of sediment on floor None required 12/01/12 547407good condition Removed debris from chamber/ replaced soil top laye 3" of sediment on floor Chamber cleaned/ cartridges replaced CONTECH ENGINEERED SOLUTIONS «;20! 2 CONTECH ENGINEERED SOLUTIONS, LLC. 800-338-1122 wwvj.corilech6S.com All Righls Reserved. Printed in the USA. CONTECH Engineered Solufions, LLC. provides site solutions for the civil engineering industry. CONTECH's portfolio includes bridges, droinoge, sanitary sewer, stormwater and earth stobilizotion products. For information on other CONTECH division offerings, visit contech-cpi.com or call 800.338.1122 The product(s) described moy be protected by one or more of the foilowing US patents: 5,322,629; 5,624,576, 5,707,527; 5,759,415; 5,788,848; 5,985,357; 6,027,639; 6,350,374; 6,406,218; 6,641,720; 6,511,595; 6,649,048; 6,991,1 14; 6,998,038; 7,186,058; 7,296,692; 7,297,266; related foreign potents or other patents pending. NOTHING IN THIS CATALOG SHOULD BE CONSTRUED AS AN EXPRESSED WARRANTY OR AN iMPLlED WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. SEE THE CONTECH STANDARD CONDITIONS OF SALE (VIEWABLE AT WWW.CONTECH-CPi.COM/C0S) FOR MORE INFORMATION, We print our brochures entirely on Forest Stewardship Council certified paper. FSC certification ensures that the paper in our brochures contain fiber from well- managed and responsibly harvested forests that meet strict environmental and socioeconomic standards. ub bf maintenance 02/12 ATTACHMENT 5 BIORETENTION BASIN SPECIFICATIONS AND DETAILS PER PLANNED INDUSTRIAL PERMIT GRAVEL LAYER EXIST. GROUND RISER OUTLET STRUCTURE 24" AMENDED SOIL MIN. INFILTRATION RA TE 5"/HR. BIORETENTION AREA BASIN TOP ELEV BASIN INVERT BOTTOM OF AMENDED SOIL LID INVERT-BOTTOM OF GRA VEL UD ORIFICE BIORETENTION AREA CROSS SECTION (TYP) NOT TO SCALE BMP H(FT) Hmax (FT) Hg (FT) LID (IfxJCHES) Ag (FT^2) Abot(FT^2) 1 0.83 1.32 0.5 1.25 2016 2016 2 0.83 1.4 0.5 1.5 4489 4489 3 0.83 1.4 0.5 1.75 3462 3003 CATCH BASIN CLOSED MESH GRATE 'PERFORATED UNDERDRAIN DRILL ORinCEHOLE ATFLOWUNE (SEE PLAN FOR SIZE) DETAIL - BIORETENTION FACIUTY OUTLET NOT TO SCALE