Loading...
HomeMy WebLinkAboutCT 00-06; BRESSI RANCH MASTER; CONCEPT WATER QUALITY PLAN; 2002-04-01CONCEPT WATER OUALITY PLAN For BRESSI RANCH, TM CT 00-06 City of Carlsbad, CA April 2002 Prepared For: LENNAR COMMUNITIES c/o LENNAR BRESSI VENTURE, LLC 5780 Fleet Street, Suite 320 Carlsbad, CA 92008 Prepared By: PROJECT DESIGN CONSULTANTS 701 B Street, Suite 800 San Diego, CA 92101 RECEIVED Document No. 1325.00 J\)^ 13 ^gQ2 ENGINEERiNG DEPARTMENT TABLE OF CONTENTS Section Page 1.0 Introduction 1 2.0 Project Background 3 3.0 Existing and Residential Pollutant Loads 4 4.0 BMP Pollutant Removal Efficiency 7 5.0 Project BMP Design Criteria 8 6.0 Project BMP Plan Implementation 8 6.1 Constmction BMP 9 6.2 Municipal/Post-Construction BMP Options 9 7.0 Conclusion 12 FIGURES 1 Vicinity Map • 2 TABLES 1 Existing Conditions and Residential Land Use Pollutant Loads and 5 Concentrations 2 BMP Treatment Controls 6 3 BMP Pollutant Removal Efficiency 7 4 Project BMP Design Criteria 8 5 Pollutant Load Estimates for the Residential PAs A-l 6 Pollutant Load Estimates for Existing Conditions A-l 7 Required Mitigation Flowrates and Volumes A-3 EXHIBITS 1 Water Quality Exhibit Map APPENDICES 1 Residential Planning Area Pollutant Loads and Support Documentation 2 Nationwide BMP Treatment Controls 3 Table 7: Required Mitigation Flowrates and Volumes 4 Constmction BMPs 5 Post-Constmction Treatment Control BMPs 6 Post-Constmction Proprietary BMPs 1.0 INTRODUCTION The Califomia State Water Quality Control Board approved Order Number 2001-01 (Order) on Febmary 21, 2001. The Order outlines the storm water discharge requirements for municipal storm water systems, which drain "development" area from watersheds within 1) the County of San Diego, 2) incorporated cities of San Diego County, and 3) San Diego Unified Port District. The City of Carlsbad is identified as one of the municipal copermittees in the Order and, therefore, subject to its requirements. From a storm water quality perspective, the new Order requires the implementation of storm water BMPs. The BMP design criteria, pursuant to the Order, are either volume- or flow-based. Specifically, volume-based BMPs must be designed to treat the volume of runoff produced from a 24-hour 85"^ percentile storm event. In general, this is equal to 0.6 inches of mnoff for San Diego County. Flow-based BMPs must be designed to treat a flow rate of 0.2 inches of rainfall per hour. In general, regardless of the criteria used, storm flow must be removed and treated before re- entering the storm drain system, or removed completely and allowed to percolate via a retention pond. This "concepf water quality report was prepared to define potential Project Best Management Practice (BMP) options that satisfy the requirements identified in the following documents: 1) Carlsbad Municipal Code Stormwater Management and Discharge Control Ordinance, 2) Standard Specificadons for Public Works Construction, 3) NPDES General Pennit for Storm Water Discharges Associated with Constmction Activity, and 4) County of San Diego Municipal NPDES Storm Water Permit (Order Number 2001-01). Specifically, this report includes the following: 1) five preUminary BMP options for the Project, and 2) BMP device information for the concept Project options. T:\WalerResources\1325-Bressi-Poimsetlia\Waler C3uality\1325WQ-cily0402,doi: 2: UJ O o Q, MELROSE DRIVE POINSETTIA LANE Figure 1. Vicinity Map REP/I3255PDR.DOC 2.0 PROJECT BACKGROUND This report provides a "concept" water quality plan for the residential land use component of the Bressi Ranch environmental document. The property, with a total acreage of approximately 585 acres, is located southeast of the intersection of El Camino Real and Palomar Airport Road in the City of Carlsbad, Califomia. The site consists of an irregular-shaped piece of property bordered on the north by Palomar Airport Road, on the west by El Camino Real, on the southwest and south by undeveloped property, and by the Rancho Carrillo development to the east (see Figure 1). The Tentative Map proposes to develop 623 dwelling units and 2,160,000 square feet of industrial space. From a drainage perspective, under existing conditions the majority of the site drains to an unnamed creek that is tributary to San Marcos Creek. This creek eventually drains to Batiquitos Lagoon, which is located southwest of the project. However, approximately 38 acres in the northwest comer of the site is a part of the Encinas Creek watershed. This area drains into a concrete ditch via a culvert beneath El Camino Real. Note that storm mnoff under both existing and proposed site conditions do not drain to Agua Hedionda Lagoon. More specifically, the site generates a lOO-year storm mnoff of 705 cfs tributary to San Marcos Creek, and 52 cfs from the 38 acres tributary to the westerly creek. Under proposed conditions the entire site drains to Batiquitos Lagoon, and will generate a lOO-year runoff of 1065 cfs (444 cfs industrial, 621 cfs residential/mixed-use, 0 cfs commercial). From a flood control perspective, detention basins will be provided along the southem boundary of the site to attenuate storm ranoff back to the existing conditions peak discharges. Also the site will generate approximately 54.9 cfs (28.2 cfs residential and 26.7 cfs industrial) of storm water treatment ranoff and 855,512 cubic feet (549,070 cu-ft residential and 306,442 cu-ft industrial) of treatment volume. Note that the BMP plans described herein focus on the residential and mixed used portions of the tentative map. Specific Industrial Site BMPs are addressed in a separate report. T:\WatCT Resources\1325-Bressi-Poiiitseltia\Water Qualily\1325WQ-cily0402.doc a 3.0 EXISTING AND RESIDENTIAL POLLUTANT LOADS The "Guidance Manual for the Preparation of Part lof the NPDES Permit Application for the Discharges from Municipal Separate Storm Sewer Systems", EPA 1991, outlines an analytical methodology for the evaluation of seasonal and/or annual pollutant loads. This approach accounts for land-use, impervious area, and anticipated mean pollutant concentrations given the land-use. Note that the pollutant concentration is primarily based on Nationwide Urban Runoff Program (NURP) data and Camp Dresser McKee Inc. (CDM) pilot studies. The equations used in the analysis are as follows: RL=[Cp-h(Ci-Cp)IMPL]*I (1) Where: RL = total average annual surface runoff from land use L (in/yr) IMPL = fractional imperviousness of land use, L I = long-term average annual precipitation (in/yr) Cp = pervious area ranoff coefficient = 0.15 CI = impervious area ranoff coefficient = 0.90 And; ML=[EMCL*RL*K*AL]*I (2) Where ML= loading factor for land use L (Ib/yr) EMCL=event mean concentration of ranoff for the lands use (mg/L): varies by land use and pollutant RL=total average annual surface runoff from land use L computed from equation 1 (in/yr) K=0.226 (unit conversion) AL=area of land use L (acres) Conceming existing and developed pollutant loading for this project. Table 1 below Hsts anticipated pollutants and concentrations that may be generated from the existing drainage areas and residential and mixed use Planning Areas (PAs). The types and concentrations of pollutants per the NURP and CDM data for residential land use are documented in the Municipal Califomia T:\Waler Resources\1325-Bri!Ssi-Poinlsellia\Waler(5ualicy\1325WQ-cily0402,doc Storm Water Best Management Practice Handbook (Municipal Manual). See Appendix 1 for pollutant load estimates for each land use condition. Also, Appendix 1 contains the support documentation for the EPA pollutant load analysis methodology, and the existing and developed residential/mixed use pollutant concentrations shown in Table 1 below. Table 1. Existing Open Space and Residential Land Use Pollutant and Concentrations Description Existing Open Space mg/L Residential mg/L Oxygen Demand and Sediment: BOD 8.0 10.8 COD 51.0 83.0 TSS 216.0 140.0 TDS 100.0 100.0 Nutrients: TP 0.23 0.47 SP 0.06 0.16 TKN 1.36 2.35 N02/N03 0.73 0.96 Heavy Metals: Pb 0.00 0.18 Cu 0.00 0.05 Zn 0.00 0.18 Cd 0.00 0.002 Total: 377.4 mg/L 338.2 mg/L *The Existing Open Space pollutant concentrations are based on Forest/Open space land use with 0.5% imperviousness. The residential pollutant concentrations are based on a medium density residential development with 40% imperviousness. Table 1 shows that the total pollutant concentration under existing land use conditions is higher than under developed conditions. This is primarily due to the high TSS concentration (sediment) that is generated under existing open space conditions. Note, however, that the remaining pollutant concentrations under developed conditions are higher than those identified under existing conditions. This is typical of an open space waterhsed that is developed for residential and/or industrial land use. The results of the pollutant load analysis show that the existing open space (within the proposed residential/mixed use/and open space areas) and the residential T:\Watcr Ri:soun:es\1325-Bressi-Pomtseltia\Waler Quality\1325WQ-cit)0402,doc e development generate pollutant loads of 58,527 Ib/yr and 109,581 Ib/yr, respectively. See Appendix 1, Tables 5 and 6 for the analysis. The following Sections address project specific BMPs and BMP plan implementation, however Table 2 below list a number of effective treatment control BMPs for each pollutant category in Table 1. In addition, more detailed BMP technical backup information from the Municipal Manual is included in Appendix 5. Table 2: BMP Treatment Controls Description Most Effective BMP Adequate BMP Oxygen Demand and Sediment: Infiltration Constracted Wetlands Wet ponds Biofilters Extended Ponds Media filtration Oil/water sep. Multiple systems Nutrients Constracted Wetlands Infiltration Wet ponds Biofilters Extended ponds Media filtration Oil/water sep. Multiple systems Heavy Metals Infiltration Constructed wetlands Wet ponds Biofilters Extended ponds Media filtration Oil/water sep. Multiple systems Oil and Grease Infiltration Constracted Wetlands Oil/water sep. Wet ponds Biofilters Extended ponds Media filtration Multiple systems T:\Wati:rResourcesM325-Bressi-Pomtsettia\WalerQuality\1325WQ-city0402,doc 4.0 BMP POLLUTANT REMOVAL EFFICIENCY In general, a number of engineering and climatic constraints ultimately affect the selection of BMP treatment controls used in a project water quality SWPPP. A critical path item in the BMP selection process is the contaminant removal efficiency associated with treatment control BMPs. Table 3 below identifies typical contaminant removal rates for a number of BMPs. In addition, Table 6 in Appendix 2 contains a matrix that includes a detailed list of BMP treatment control, associated benefits, and pollutant removal efficiencies. Listed at the end of this document are the references used in development of the data. Table 3: BMP Pollutant Removal Efficiency BMP Type Suspended Nitrogen Phosphorous Pathogens Metals Solids (%) (%) (%) (%) (%) Dry Detention Basin 30-65 15-45 15-45 <30 15-45 Retention Basins 50-80 30-65 30-65 <30 50-80 Constructed Wetlands 50-80 <30 15-45 <30 50-80 Inflitration Basins 50-80 50-80 50-80 65-100 50-80 Porous Pavement 65-100 65-100 30-65 65-100 65-100 Grass swales 30-65 15-45 15-45 <30 15-45 Vegetated Filter Strips ^ 50-80 50-80 50-80 <30 30-65 T:\WalerRcsourccs\1325-Bressi-Pomisetlia\Water Qualiiy\1325WQ-cit)<)402.doc 5.0 PROJECT BMP DESIGN CRITERIA Grass-lined bio-filters/strips and retention/wetiand basins have been identified as potential BMP candidates for this project. The design of these BMPs is primarily based on the numeric sizing criteria defined in Section 1.0. In general, Table 4: below summarizes the criteria that should be implemented in the design of these BMPs: Table 4: BMP Design Criteria BMP BMP Hydrology Treatment Area/Volume Design Constraints Grass-lined Biofilter/Strip Flow-based: 0=CIA I = 0.2 in/hour C= ranoff coefficient A = PA acreage 1000 sqft. of biofilter/acre of impervious area. Use geometry and longitudinal slope that maintain sheet flow and low conveyance velocities. Retention Basin/Wetland Pond Volume based: 0.6- inches of ranoff 0.6-inches of ranoff over the impervious portion of the drainage area. Potential soil and ground water constraints must be addressed before selecting this BMP. Geotechical and City must be consulted regarding these issues. Retention time should range between 40 and 72 hours to promote treatment efficiency and control for vector control. 6.0 PROJECT BMP PLAN IMPLEMENTATION This Section identifies several "concept" BMP options that meet the applicable stormwater and water quality ordinance requirements. This includes incorporating BMPs that minimize runoff contamination and volume from the site. The plan was developed per the proposed roadway and lot layout/density associated with the site. BMPs other than those identified in the plan, may be used during final engineering. T:\WalerResources\1325-Bressi-Pointsettia\WalerQualily\1325WQ-ciIy0402.doc The following Sections address the use of constraction- and post-construction BMPs. Note that the BMP Project options are discussed in Section 6.2. 6.1 Construction BMP During constraction, BMPs such as desilting basins and other erosion control measures will be employed, consistent with the NPDES Storm Water Pollution Prevention Program (SWPPP). The objectives of the SWPPP are to: (1) identify all pollutant sources, including sources of sediment that may affect the water quality of stormwater discharges associated with construction activity from the construction site; (2) identify nonstormwater discharges; (3) identify, constract, implement in accordance with a time schedule, and maintain BMPs to reduce or eliminate pollutants in stormwater discharges and authorized nonstormwater discharges from the constraction site during construction; and (4) develop a maintenance schedule for BMPs installed during constraction designed to reduce or eliminate pollutants after constraction is completed (post-construction BMPs). BMPs, in addition to desilting basins, may include silt fences, sand bags, and gravel bags. See Appendix 4 for Construction BMPs. 6.2 Municipal / Post-Construction BMP Plan Options PDC has identified several water quality BMP plan options for the Bressi Ranch project that should meet the stormwater requirements identified in the Order. Note, however, that the City has yet to implement its policy for compliance with the Order, or develop specific BMP Standard Drawings. Therefore, the following BMP plan is preliminary and is subject to change pending City review and implementation of future policy requirements. Per City of Carlsbad comments on the July 2001 version of this report, it should be noted that: Each Planning Area is responsible for on-site control of pollutants. Basins, landscaped filters, or improved BMPs shall be located onsite of each planning area and should be maintained by the respective homeowner's association. BMP Plan Options 1 and 2 below address the use of in-line treatment methods using flow based CDS Pollutant Trap Treatment Units (Unit(s)) (see Appendix 6 for more information on these devices). However, Options 3 and 4 also include the use of retention basins, which are a volume T:\WalerResources\1325-Bressi-Pomlsetlia\WalerQualiiy\1325WQ-city0402.doc based BMP. Note that additional BMP plan options could be developed that utilize an assortment of BMPs, however. Plan Options 1-4 presented herein provide a cost effective water quality approach that compliments the current site planning. Note that Fossil Filter Inlet Inserts were provided as an option in the July 2001 version of this report. Based on City comments, the Fossil Filter Inlet Inserts have been removed as a BMP option. The City does not consider Inlet Inserts as a favored BMP for tentative map stage design and planning. See Exhibit A for the BMP locations discussed below and Table 7 in Appendix 3 for required mitigation flowrates and volumes for each location and PA. Option 1: This option provides a BMP plan that treats the storm flow with a single CDS Unit near the downstream end of each major storm drain system and specific pad locations that drain directly into adjacent canyon watercourses. The Units associated with the aforementioned major storm drain systems would be located at locations A and F and would accommodate both residential and industrial storm flows. In addition, it is anticipated that Units would also be constracted at locations B-E, and I and J, and would drain directly into the canyon. Note that the Units at locations B-E could be reduced in number by combining flows from pads prior to discharging into nearby canyons. Option 2: This option provides a BMP plan that treats the storm flow within each individual industrial PA (PA 1-5 and 14), at collector roadway inlets, and surrounding residential and mixed-use areas (PAs 6-13, and 15). In this option. Units would be exclusively used within the industrial PAs and would be used to treat flows from the surrounding residential and mixed-use PAs. The Units for the residential and mixed use PAs would be constracted at the downstream end of the residential storm drain systems prior to combining with industrial site discharges at locations F, O, P, and Q. Option 3: This option provides a BMP Plan that treats storm flow from the residential and mixed-use areas with Units, grass-lined swales, and retention basins. Storm flow from the industrial PAs would be treated with Units. Units would be provided at locations O, P, and Q. A T:\Waler Rcsourci:s\1325-Bressi-Pointseltia\Waler Quality\1325WQ-cil)<)402.doc retention basin would be provided at location G to treat flows from PAs 6, 10, and 15a. Either Units, retention basins or grass-lined swales could be used to treat flows from PA 11. Option 4: Similar to Option 3, this option treats storm flows with Units, within the industrial PAs, and retention basins and grass-lined swales within open space, park areas, and roadway parkway/medians. Storm flows from PAs 6, 10, and 15a could be treated with a retention basin at location G. Some treatment within PAs 6 and 10 could possibly be provided with grass-lined swales that would be constracted within the neighborhood parks. Storm flow from PA 11 would be treated with retention basins or grass-lined swales. PAs 7, 8, 9, 12, and 13 could make use of open space areas for some treatment of flows. It is anticipated that one or more CDS units would be required at locations O, P, and Q. Note that further investigation of Options 3 and 4 is required in order to determine the trae feasibility of using flow-based BMPs such as water quality basins and grass lined swales. The feasibility is dependent on the ability to direct first-flush flows through these areas, the amount of land available for basins and swales in relation to the required treatment volumes, soil infiltration rates, and the avoidance of co-mingling treated and untreated flows. Some of these options include the possibility of combining BMPs for several Planning Areas. The combination of Planning Area BMPs will require futher study in light of the City's request that each Planning Area be individually responsible for on-site pollutant control. In some specifically approved cases, BMPs for different Planning Areas could possibly be combined. BMP Plan Assumptions: The following assumptions were made in calculating the required BMP sizes: • Only onsite flows will be treated. All offsite flow treatment will be the responsibility of the upstream owners. • Runoff coefficients, 'C values, of 0.55, 0.60, and 0.95 were used in the runoff calculations for residential, mixed-use, and industrial areas respectively. • CDS units will be accepted for use in the City of Carlsbad. T:\Waler Resounxs\1325-Bressi-Pomlsetlia\Water Qualjly\1325WQ-cily0402,doc j j • BMPs for adjacent Planning Areas can be combined in some cases. 5.0 CONCLUSION This "preliminary" water quality report has been prepared to define Best Management Plan (BMP) options, or schemes, that satisfy the requirements identified in the following documents: 1) Carlsbad Municipal Code Stormwater Management and Discharge Control Ordinance, 2) Standard Specifications for Public Works Constraction, 3) NPDES General Permit for Storm Water Discharges Associated with Constraction Activity issued by the State Water Resources Control Board, and 4) San Diego NPDES Municipal Storm Water Permit (Order Number 2001- 01). Specifically, this report includes the following: 1) four preliminary BMP options for the Project, and 2) BMP device information for these options. Each Planning Area is responsible for on-site control of pollutants. Basins, landscaped filters, or improved BMPs shall be located onsite of each planning area and should be maintained by the respective homeowner's association. T:\Water Resources\I325-Bressi-Pomts<!tlia\Water Quality\1325WO-i:ily0402.doc j 2 APPENDIX 1 Residential Land Use Pollutant Loads and Support Documentation T:\Waler Rcsoiiices\1325-Bressi-Pomtsettia\Water Quality\1325WQ-city.doc Table 5. Pollutant Load Estimates for the Residential PAs AVERAGE ANNUAL SURFACE RUNOFF (R) Cp Ci IMP 1 (in.) R(l) in/yr 0.15 0.9 0.4 10 4.5 1 LOADING FACTOR FOR RESIDENTIAL AND MIXED LAND USE (M,) PA EMC Rl K Area Ml (mg/1) (in/yr) (conv. factor) (acres) Ib/yr PA6 338.2 4.5 0.2266 19.0 6552 PA7 338.2 4.5 0.2266 22.7 7828 PAS 338.2 4.5 0.2266 22.4 7725 PA9 338.2 4.5 0.2266 34.0 11725 PA10 338.2 4.5 0.2266 34.0 11725 PAIIa 338.2 4.5 0.2266 12.0 4138 PAIIb 338.2 4.5 0.2266 12.0 4138 PAIIc 338.2 4.5 0.2266 7.0 2414 PAIId 338.2 4.5 0.2266 11.0 3793 PA12a 338.2 45 0.2266 13.0 4483 PAI 2b 338.2 4.5 0.2266 15.0 5173 PAI 3 338.2 4.5 0.2266 13.0 4483 PAI 4 338.2 4.5 0.2266 1.0 345 PAI 5a 338.2 4.5 0.2266 22.0 7587 PAI 5b 338.2 4.5 0.2266 14.0 4828 Open Space 337.4 1.54 0.2266 192.3 22641 Totals: 444.4 Notes: 1. The above calculations assumes an average imperviousness of 40% within the residential/mixed use areas (per City recommendation). 109581 Table 6. Pollutant Load Estimates for Existing Conditions AVERAGE ANNUAL SURFACE RUNOFF (R) Cp Ci IMP 1 R(l) (in.) in/yr 0.15 0.9 0.005 10 1.54 LOADING FACTOR FOR EXISTING LAND USE (M,) (FOR ENTIRE SITE - 585 ac) Drainage EMC Rl K Area Ml Basin (mg/1) (in/yr) (conv. factor) (acres) Ib/yr 1 377.4 1.54 0.2266 547 72039 2 377.4 1.54 0.2266 38 5005 Notes: 1. Drainage Basin Number 1 is tributary to San Marcos Creek/Batiquitos Lagoon. 2. Drainage Basin Number 2 is tributary to Encinas along Palomar Airport Road. LOADING FACTOR FOR EXISTING LAND USE (M,) (WITHIN THE FUTURE RESIDENTIAL/MIXED USE/OPEN SPACE AREAS) Drainage EMC Rl K Area Ml Basin (mg/1) (in/yr) (conv. factor) (acres) Ib/yr 1 377.4 1.54 0.2266 444.4 58527 Notes: 1. Drainage Basin Number 1 is tributary to San Marcos Creel</Batiquitos Lagoon. Step 4 - Select BMPs The most cost-effective BMP scenario is selected using Worksheet 2 in Chapter 3. The first step in setting up Worksheet 2 is to determine the average aimual pollutant loading from the site prior to development (i.e, pasture with no BMPs), the annual poUutant load increase due to the development, and the average annual pollutant loading under each of the three BMP scenarios identified in Step 3. The purpose is to compare projected non-point source pollutant loads before and after development in order to identify the load reductions that could be achieved by placing different BMP options. The NURP data and/or other local studies could be used for pollutant load estimates, runoff estimates, or removal efficiencies. For this example, pollutant loads were simulated using the Camp Dresser & McKee Inc. (CDM) Watershed Management Model (WMM). WMM is a spreadsheet-based tool for annual and/or seasonal load evaluations based on the methodology oudined in the Guidance Manual for the Preparation of Part 1 of the NPDES Pennit Application for Discharges from Municipal Separate Storm Sewer Svstems. EPA, 1991. EMCs and impervious values for WMM are shown in Table 2. These are based upon NURP data and CDM experience. For WMM, annual runoff volumes for the pervious/impervious areas in each land use category are calculated by multiplying the average annual rainfall volume by a ranoff coefficient. A runoff coefficient of 0.9 is typically used for impervious areas (i.e., 90 percent of the rainfall is assumed to be converted to runoff from the impervious fraction of each land use). A pervious area ranoff coefficient of 0.15 is typically used. The total average annual surface ranoff firom a given land use L is calculated by weighting the impervious and pervious area ranoff faaors for each land use category as follows: Rt = [Cf + (C,- Cf) IMP^ ] *I Equation 1 Where: R^ = total average aimual surface ranoff from land use L (in/yr) IMPL = fractional imperviousness of land use L from Table 2 I = long-term average annual precipitation (in/yr) Cp = pervious area runoff coefficient = 0.15 Cl = impervious area runoff coefficient = 0.90. The WMM generates nonpoint source pollution loads (expressed as Ibs/yr) that vary by land use and the percent imperviousness associated with each land use. The pollution loading factor ML is computed for land use L by the following equation: Afi = EMCL *RL*K*AL Equation 2 Wbere: ML = loading factor for land use L Gb/yr) EMCL = event mean concentration of runoff from land use L (mg/L); EMCL varies by land use and by poUutant RL = total average annual surface runoff bota land use L computed from Equation 1 (in/yr) K = 02266, a unit conversion constant AL = area of land use L (acres). The loads are then summed for a given area or scenario to produce summary results without BMPs. BMP efficiencies are then s^Ued as fractional removal coefficients to reduce aimual loads. Municipal Handbook B - 4 March, 1993 fr I Event Mean Concentrations And Impervious Percentages Assigned For The Watershed Management Model Oxygen Demand & Sediment Nutrients Heavy Metals Land Use Percent Impervious BOD mg/L CDD mg/L TSS mg/L TDS mg/L TP mg/L mg/L TKN mg/L N023 mg/L Pb mg/L Cu mg/L Zn mg/L C!d mg/L Forest/Open 0.5% 8.0 51 216 100 0.23 0.06 1.36 0.73 0.00 0.00 0.00 0.00 Agricu Uure/Pastiue 0.5% 8.0 51 216 100 0.23 0.06 1.36 0.73 0.00 0.00 0.00 0.00 Cropland 0.5% 8.0 51 216 IOO 0.23 0.06 1.36 0.73 0.00 0.00 0.00 0.00 Low Density Residential 10.0% 10.8 83 140 100 0.47 0.16 2.35 0.96 0.18 0.05 0.18 O.OOi Medium Density Residential 30.0% 10.8 83 140 100 0.47 0.16 2.35 0.96 0.18 0.05 0.18 0.002 High Density Residential 50.0% 10.8 83 140 100 0.47 0.16 2.35 0.96 0.18 0.05 0.18 0.002 Commercial 90.0% 9,7 61 91 100 0.24 0.10 1.28 0.63 0.13 0.04 0.3^ 0.002 Office/Light Industrial 70.0% ^.7 61 91 100 0.24 0.10 1.28 0.63 0.13 0.04 0.33 O.OOi Heavy Industrial 80.0% 9.7 61 91 100 0.24 0.10 1.28 0.63 0.13 0.04 O.OOi Water 100.0% 3.0 22 26 100 0.03 0.01 0.60 0.60 0.00 0.00 0.11 0.000 Wetlands 0.5% 8.0 51 216 100 0.23 0.06 1.36 0.73 0.00 6.t)() 0.00 0.00 Major Highway 90.0% 9.7 103 142 100 0.44 0.17 1.78 0.83 0.53 0.05 0.3^ O.OOil I n er Source: EPA, 1983 and CDM experience APPENDIX 2 Nationwide BMP Treatment Controls TAWater Resources\1325-Bressi-Pomtsettia\Waler Quality\1325WQ-ciIy.doc Nationwide Examples of Treatment Control (Structural) Best Management Practices (BMPs) Treatment Control (Source) Limitations Benefils Removal Efficiency Capital Cost (approximate) O&M Cost (approximate) liifiltrattt)n - a family of treatment systems in which the majority of Ihe runoff from small storms is infiltrated in the ground rather than discharged into a surface water body. (I) Infiltration Trench - is an excavated trench (3 to 12 feet deep), backfilled with stone aggregate, and lined with filler fabric. (23) Il is used to treat a small portion of the runoff by detaining storm water for short periods until it percolates down to the groundwater table. (21) Useful life is usually around 10 years. (20) Pond (Basin) - consist of shallow, tlat basins excavated in pervious ground, with inlet and outlet structures lo regulate llow. (19) Useful Life is usually around 25-years. (20) •potential loss of infiltrative capacity. (1) •applicability depends on specific site characteristics/opportunities (slope, soil types, proximity to water table). (23) •potential groundwaier contamination. (1) *not suitable for sites that conlain chemical or hazardous material. (23) *may need to be preceded by appropriate pretreatment. (23) •relatively short life span. (23) •efficient removal of pollulanis. (I) •can recharge groundwater supplies. (2) •provides localized streambank erosion conlrol. (2) •easy lo fil into unutilized areas ofdevelopmeni sites. (2) •an effedive runoff control. (1) •increases basetlow in nearby streams. (23) •Low land use requirement. (20) •potential loss of infiltrative capaciiy. (I) •low removal of dissolved pollulanis in very course .soils. (1) •possible nuisance (odor, mosquito). (2) •frequenl maintenance requirement. (2) •risk of groundwaier contamination. (I) • High land use requirement. (20) •achieves high levels of particulate pollutant removal. (I) * can recharge groundwaier supplies. (2) •an effective runoff conlrol. (1) •can serve tributary areas up to 50 acres. (I) •provides localized streambank erosion control. (2) •cosl effective. (2) • nitrogen compounds 40% lo %mv. (2) • phosphorus compounds 40% lo 80%. (2) • combined nilrogen and phosphorus compounds 45% to 75% (depending on design). (8) • lolal suspended solids 75%. (20) •lolal phosphorous 60%. (20) • lolal nilrogen 55%. (20) •COD 65%. (20) • Lead 65%. (20) • Zinc 65%. (20) • .$4,900/acre (prorated using ENR index from 1992 cos0.(5) •$3.6 to $10.70/cubic feel storage (prorated using ENR index from 1986 cost). (20) • nitrogen compounds 40%. 10 80%. (2) • phosphorus compounds 40'/r lo 80%. (2) r • combined nilrogen and 1 phosphorus compounds 45'/(' lo 75% (depending on design). (8) • lotal suspended solids 75%. (20) •lolal phosphorous 65%. (20) • lolal nilrogen 60%. (20) •COD 65%. (20) • Lead 65'7<i. (20) • Zinc 65%. (20) * $36,900/million gallons (prorated using ENR index from 1992 cost). (5) • $0.60 10 $ I/cubic feel storage (prorated using ENR index from 1986 cost). (20) • $l,800/acre/year (prorated using ENR index from 1992 cos0. (5) •9% of Capilal Cosl (20) • $l,200/million gallons/year (prorated using ENR index from 1992 cosO- (5) • 7% of Capilal Cosl (20) Nationwide Examples of Treatment Control (Structural) Best Management Practices (BMPs) Treatment Conlrol (Source) Limilations Benefils Removal Efficiency Capilal Cosl (approximate) O&M Cost (approximale) Porous Pavement - is an alternative lo conventional pavement whereby runotT is diverted Ihrough a porous asphalt layer and into an underground stone reservoir. (10) Useful life is around 10 years. (20) ^potential loss of infiltrative capacity. (1) i>15% failure rate due to clogging, resurfacing or just failure afler construciion. (10) Jihigh maintenance - requires special vacuum sweeping or jet hosing. (10) Jimay require twice as much material as without porous pavement to achieve the needed strength. (10) J)unsuilable in fill sites and steep slopes. (5) > potential risk of groundwater conlaminaiion. (1) •limited efficiency (6 months). (23) J> achieves high levels of pollutant removal. (1) Jl groundwater recharge. (2) >localize streambank erosion conlrol. (2) >reduced land consumplion. (2) Jielimination of curbs and gutters. (2) Jisafer driving surface. (2) • nitrogen compounds 60% to 80%. (2) • phosphorus compounds 40% to 80%. (2) •nilrogen and phosphorus compounds 45% to 75% (depending on design). (8) • sedimenl 82 lo 95%. (23) • tolal phosphorus compounds 65%. (23) • tolal nilrogen compounds 80 to 85%. (23) • tolal suspended solids 90%. (20) •lotal phosphorous. 65% (20) • lolal nilrogen 85%. (20) •COD 80%. (20) • Lead 100%. (20) • Zinc 100%. (20) • $123,000/acre (prorated using ENR index from 1992 cosO- (5) • $2.IO/square feel (prorated using ENR index from 1987 cost) (incremental cost beyond the conventional asphalt pavement). (20) • $250/acre/year (prorated using ENR index from 1992 cosO. (5) • $0.14/square feet/year (prorated using ENR index from 1987 cosl). (incremental cosl beyond the conventional asphalt pavement). (20) * $1.7-$3.5/11'' (prorated using ENR index from 1981 COSI) (incremeniul cosl beyond Ihe convenlional asphalt pavement) (20) • -$0.07/fl' feel (prorated using ENR index from 1981 cosl) (incremental cosl beyond the conventional asphalt pavement) (20) Concrete Grid Pavement - are lallice grid structures wilh grassed or pervious malerial placed in the grid openings. (1) Useful life is usually around 20 years. (20) /irequire regular maintenance. (20) Jinot suitable for high traffic areas. (20) Jl potential groundwater contamination. (20) Jionly feasible where soil is permeable. (20) J" groundwater recharge. (20) Jican provide peak flow conlrol. (20) •lolal nitrogen 90%. (20) • lolal phosphorus compounds 90%. (20) • lolal suspended solids 90%. (20) •COD 90%. (20) • Lead 90%. (20) • Zinc 90%. (20) Infiltration Drainfields - a sysiem composed ofa prelrealmenl slructure, a manifold sysiem, and a drainfield. (28) •high maintenance when sedimenl loads are heavy. (28) •shorl life span ifnot well maintained. (28) •nol suitable in regions wilh clay or silly soils. (28) •anaerobic condilions could clog the soil. (28) •potential groundwater conlaminaiion. (28) Jl groundwaier recharge. (28) •used to conlrol runoff. (28) • depends on design - lillle moniloring dala currenlly available. Polenlially 100% of pollulani could be prevented from entering surface waler. (28) Approx. $72,000 for a drainfield wilh dimensions: 100 fl long, 50 feel wide, 8 feel deep with 4 fl cover. (28) Nationwide Examples of Treatment Control (Structural) Best Management Practices (BMPs) Treatment Conlrol (Source) Wel Detention Ponds - small artificial impoundments with emergent wetland vegeiation around the perimeter designed for the removal of parliculale matter and dissolved nutrients. (19) Useful life is around 50 years. (20) Limitations Wetlands - constructed wetlands are a single stage treatment system consisting ofa forebay and micro pool with aquatic plants. They remove high levels of parliculale, as well as some dissolved contaminants. (19) Useful life is around 50 years. (20) Jl maintaining oxygen supply in Ihe pond. (1) Jl need of supplemental waler lo mainlain waler level. (1) Jiland constraints, infeasible in dense urban areas. (1) Jl local climate might affect biological uptake. (27) Jieventual need for costly sediment removal. (2) * potential nuisance (mosquito, odor, algae). (2) •potential stratification and anoxic conditions. (27) Benefils Jineed of supplemental water lo mainlain waler level. (1) Jl potemial nutrient release in the winler. (19) Jl redudion in hydraulic capacity wilh plant growth. (19) Jl wetland area less lhan 2%' of watershed area. (10) •potential groundwaier contamination. (26) • high land requirements. (20) Jl achieves high levels of soluble and organic nutrient removal. (2) Jicreation of local wildlife habitat. (2) Jl decrease potential for downstream flooding. (27) Jl recreational and landscape amenities. (2) Jl decrease potential downstream slream bank erosion. (19) Jl passive recrealion and wildlife suppori. (1) Jl improve downstream waler and habitat quality. (26) Jl flood allenuation. (26) Jl achieves high levels pollutant removal. (I) Removal Efficiency nitrogen 20% lo 60%. (2) phospht)rus 40% lo 80%.. (2) • nilrogen & phosphorous 30% lo 70% (depending on volume ralio). (8) • total suspended solids 50%. lo 90% (27) & 60% (20). • total phosphorus 30% to 90% (27) & 45% (20). • tolal nitrogen 35%. (20) • soluble nulrienls 40% to 80%. (27) • lead 70% lo 80%. (27) & 75% (20). • zinc 40% lo 50% (27) & 60% (20). • COD 40%. (20) • tolal suspended solids 67% (26) & 65% (20). • lolal phosphorus 49%> (26) & 25% (20). • lolal nitrogen 28% (26) & 20%. (20). • organic carbon 34%. (26) • COD 50%. (20) • petroleum hydrocarbons 87%. (26) • cadmium 36%. (26) •copper41%. (26) • lead 62% (26) & 65% (20). • zinc 45% (26) & 35% (20). • bacleria 77%. (26) Capilal Cosl (approximale) $17.50 to $35 per cubic meter of storage area (27) $26,000 lo $55,000 per acre of wetland. (26) O&M Cost (approximate) 3 10 5 percenl of consiruction cosl per year (27) 2 percenl of consiruction cosl per year. (26) Nationwide Examples of Treatment Control (Structural) Best Management Practices (BMPs) Treatment Conlrol (Source) Limitations Benefits Removal Efficiency Capilal Cost (approximale) O&M Cost (approximale) Biofilters - Systems designed to pass slorm water runoff slowly over a vegetated surface in the form of a swale or strip to filter pollutants and lo infiltrate Ihe runoff. (19) Bioretention - system designed to treat runoff. The runoff is conveyed as sheet flow to the treatment area, which consists of a grass buffer strip, sand bed, ponding area, organic layer or mulch layer, planting soil, and plants. (33) •cold climate may hinder infiltrative capaciiy. (33) •not suitable for slopes grealer lhan 20 percent. (33) •clogging may occur in high sediment load areas. (33) •enhance qualily of downstream water bodies. (33) •improves area's landscaping. (33) •provide shade and wind breaks. (33) • lolal Phosphorus 70 to 83%. (33) • metals (copper, lead, zinc) 93 to 98%. (33) • TKN 68% to 80%. (33) • tolal suspended solids 90%. (33) • organics 90%. (33) • bacleria 90%. (33) $500 for new development of a biorelenlion, $6,500 for relrofilling a sile into a bioretetion area (33) Vegetated Swale - is a broad, shallow channel (typically trapezoidal shaped) with a dense stand of vegetation covering the side slopes and bottom. (29) Useful life is around 50 years. (20) Jl generally incapable of removing nutrients. (2) •can become drowning hazards, mosquito breeding areas. (29) Jinot appropriale for sleep topography, very flat grades. (29) Jl tributary area limiled to a maximum of 5 acres. (19) Jidifficull lo avoid channelization. (19) •ineffective in large slorms due lo high velocity flows. (29) > design to convey runoff of 2 year storm, wilh freeboard of 10 year slorm. (19) • low land requirement. (20) Jisuitable for small residential areas. (1) Jican removes particulate pollulanis al rates similar lo wet ponds. (1) •redudion of peak flows. (29) •lower capital cosl. (29) •promotion of runoff infiltralion. (29) * low land requirements. (20) • nilrogen 0 to 60% (2) • total nitrogen 10%. (20) • phosphorus 0 to 60% (2) • loial phosphorus 9% (29) & 20% (20). • COD 25%. (20) • oxygen demanding subslances 67%. (29) • total suspended solids 81% (29) & 60% (20). • nilrate 38%. (29) • hydrocarbons 62%. (29) • cadmium 42%. (29) • lead 67% (29) & 70% (20). •zinc 71% (29) & 60% (20). • copper 51%. (29) •$6.80 to $12.50 per linear foot (prorated using ENR index from 1987 COSI). (29) •$10.80 to $63.40 per linear fool (prorated using ENR index from 1991 cosl). (29) • typical lotal for a 1.5 ft. deep, 10 fl wide, 1,000 li long Low-$8,100 Moderate - $14,870 High-$21,640 Prorated using ENR index from 1991 cosO- (29) • $0.73 - $0.95 per linear foot (prorated using ENR index from 1991 cosO. (29) • $l/linear fool 9pioraled using ENR index from 1987 cosl). (20) Nationwide Examples of Treatment Control (Structural) Best Management Practices (BMPs) Treatment Conlrol (Source) Limitations Benefils Removal Efficiency Capilal Cosl (approximate) O&M Cosl (approximate) Infiltralion (Vegetative Filter) Strip - are broad surfaces wilh a full grass cover lhal allows slorm water lo flow in a relatively thin sheels (21) Useful life is around 50 years (20). •sheet flow may be difficult to allain. (1) •nol appropriale for sleep slopes. (19) •iribuiary area limited lo 5 acres. (19) •suitable for parking lots. (1) •slows runoff tlow. (1) •removes parliculale pollutants. (1) • nitiogen 0 to 40%. (2) • phosphorus 0 lo 40%. (2) • tolal suspended solids 65%. (20) • lolal phosphorous 40%. (20) • lolal nitrogen 40%. (20) • COD 40%. (20) • lead 45%. (20) • zinc 60%.. (20) • $3,100/acre (prorated using ENR index from 1992 cost). (5) • $310/acre/yr (prorated using ENR index from 1992 cosl). (5) •$139 to $l,100/acre/year (prorated using ENR index from 1987 cost). (20) Nationwide Examples of Treatment Control (Structural) Best Management Practices (BMPs) Treatment Conlrol (Source) Limilalions Benefils Removal Efllcieney Capilal Cosl (approximale) O&M Cosl (approximate) Extended Detention Basins - consist of a settling basin wilh an outlet sized lo remove particulate matter by slowly releasing accumulated runoff over a 24 to 40 hour period. "Dry" detention basins may be designed lo empty between usages. (19) Useful life is usually 50 years. (20) •occasional nuisance in inundated portion. (19) •inability lo vegetation may result in erosion and re- suspension. (1) •limiled orifice diameter preclude use in small watersheds. (1) •requires differential in elevation al inlel and oullel. (1) •frequent sedimenl maintenance. (19) • High land requirement. (20) •creation of local wildlife habilal. (2) •recreaiional use in inundated poriion. (2) •can remove soluble nulrienls by shallow marsh or permanenl pool. (2) •suitable for sites over 10 acres. (10) •lemporary slorage of runoff. (1) •no need of supplemenlal waler. (1) •proiection for downstream channel erosion. (2) • nilrogen 20% lo 60%. (2) • phosphorus 20% lo 80% (2)& 10% to .30%. (10) • nitrogen and phosphorus 30% to 70% (depending on volume ratio). (8) • soluble nulrienls - low or negative. (10) • lolal suspended solids 45% (20) & 88% (44). • nilrate 15% (44). • nitrite 61% (44). • oil and grease 56%. (44) • fecal coliform 45%. (44) tolal pelroleum hydrocarbons 17% to 20%. (44) • TKN 40%. (44) • ammonia 5%.. (440 •tolal phosphorous 25% (20) & 57% (44). • tolal nitrogen 30%. (20) •COD 20% (20) & (44). • lead 20% (20) & 55% (44). • zinc 20% (20) & 47% (44). • chromium 68%. (44) • copper 37%i. (44) • nickel 62%. (44) $123,000/million gallons (prorated using ENR index from 1992 cost). (5) * $l,230/million gallons/year (prorated using ENR index from 1992 cost). (5) • 4%. of capilal cost. (20) Nationwide Examples of Treatment Control (Structural) Best Management Practices (BMPs) Tieatment Control (Source) Modular Treatment Sy.steins StormTreal"^ Sysiem (STS) - irealmenl technology consisting of a series of sedimentation chambers and constructed wetlands. The 9.5 feet diameter recycled polyethylene modular treats slorm water with sedimentation chambers, where pollutants are removed through sedimentation and filtration, then Ihe waler is conveyed lo a surrounding constructed wetland. Vegeiation in the wetland varies depending on local conditions. Because the system is relatively new, there is no data available on lifetime of the system. It is estimated that the plants and Ihe gravel in the system need to be replaced every 10-20 years. (32^ Hydrodynamic Separators - are tlow- ihrough structures with a settling or separation unit lo remove sediments and olher pollutants that are widely used. With proper upkeep, useful life is over 30 years. (25)^ Downstream Defender^^ - designed to capture settleable solids, floatables and oil and grease. It utilizes a sloping base, a dip plate and internal components lo aid in pollutant removal. (25) Continuous Deflection Separator (CDS) - pre cast unils placed downstream of freeway drain inlets to capture sediment and debris. These underground units create a vortex of water that allows water to escape through the screen, while contaminants are deflected into the sump. (21) Limilalions may require modificalions to function in different environments. (32) • relatively new and remains lo be tested in different geographical locations. • requires frequent inspections and maintenance is site-specific. (25) • suitable for gross pollutant removal. (21) Benefits •protect groundwaier by removing pollutants prior lo infiltralion. (32) •high removal rales. (32) spill containment feature. (32) •soil types and high water table won't limil effectiveness. (32) Jl intended to screen litter, fine sand and larger particles. (21) Jiact as a firsl screen inlluence for trash and debris, vegetative material, oil and grease, heavy metals. (21) Removal Efficiency • fecal coliform bacteria 97%. (32) • tolal suspended solids 99% (32) • COD 82%. (32) • lotal dissolved nilrogen 77%. (32) • phosphorus 90%. (32) • lotal pelroleum hydrocarbons 90%. (32) • lead 77%. (32) • chromium 98%. (32) • zinc 90%. (32) Can achieve 90% particle removal for flows from 0.75 cfs to 13 cfs (25) oil and grease-77% (34) Capital Cosl (approximale) $4,900 per unit -t- $500 to $1,000 installation cost + $350 lo $400 for additional material (32) $10,000 to $35,000 per pre cast unit (23) $2,300 to $7,200 per cubic feet second capaciiy (23) O&M Cosl (approximale) $80 to $ 120 per tank for removal of sedimenl (32) Nationwide Examples of Treatment Control (Structural) Best Management Practices (BMPs) Treatment Control (Source) Limilalions Benefils Removal Efficiency Capilal Cosl (approximale) O&M Cost (approximale) Continuous Deflection Separator (CDS) with Sorbents. Applicalion of different types of sorbents in the CDS unils. OARS^*^ - is a rubber type off sorbent (34) Rubberizer - is composed of a mixture of hydrocarbon polymers and additives. (34) Aluminum Silicate: Xsorb™ is made from a natural blend of silica minerals, which when expanded in our unique manufacturing process, make a while granular malerial lhat absorbs spills instantly on contact (web) Sponge Rok™ - primarily sold as a soil bulking agent (34) Nanofiber™ - is a polypropylene adsorbent. (34) • requires frequent inspections and maintenance is site-specific. (25) •sorbenis remove many limes their own weighi (34) •could be used oil spill control. (34) OARS: oil and grease - 82%. 83%, 86%. 94% (34) Rubberizer: oil and grease 86%. (34) Xsorb: oil and grease 79%. (34) Sponge Rok: oil and grease 41%. (34) Nanofiber: oil and grease 87%. (34) Nationwide Examples of Treatment Control (Structural) Best Management Practices (BMPs) Treatment Conlrol (Source) Stormceptor® - This sysiem is a stormwater interceptor lhat efficiently removes sedimenl and oil from stormwater runoff and stores these pollutants for safe and easy removal. Units are available in prefabricated sizes up to 12 feet in diameter by 6 to 8 feet deep. They re designed to trap and retain a variety of non-point source pollutants, using a by-pass chamber and treatment chamber. A fiberglass insert separates the upper (by-pass) and lower (separation/holding) chambers. (25) Limilalions • requires frequent inspections and maintenance is site-specific. (25) Benefils Vortechs™ - a major advancement in oil and grit separator technology. Vortechs unils removes grit, contaminated sediments, heavy metals, and oily floating pollutants from surface runoff. It is a stormwater treatment system consisting of four structures to treat stormwater: a baffle wall, a grit chamber, an oil chamber and a flow control chamber. This sysiem combines swirl-concentrator and tlow-conlrol technologies. (25) •most effective when .separation of heavy parliculale or lloalable from wel wealher runoff. (25) •suspended solids are nol effectively removed. (25) • requires frequent inspections and maintenance is site-specific. (25) •use for redevelopment projecis of more lhan 2.500 sq. feel where Ihere was no pervious slorm water management. (25) •projects lhal double Ihe impervious layer. (25) •easy lo design in new or relrofil applications. (35) •inexpensive lo service and maintain. (35) •internal bypass prevents release of irapped pollutants. (35) •Ideal for highways, industrial properlies, gas stations, parking lots and sites where there is a potential for oil or chemical spills. •suited for areas with limiled land available (25) •good for "holspols" such as gas stations (high concentrations). (25) •able to treat runoff Hows from 1.6 cfs to 25 cfs. (25) Removal Efficiency • tolal suspended solids 80%. (35) • free oils 95%. (35) •oil 98.5%. (36) • inorganic sedimenl 80%. (36) • organic sediment 70%. (36) • lolal suspended solids 51.5%. (36) • oil and grease 43.2%. (36) • zinc .39.1%. (36) • total organic carbon 31.4%. (36) • chemical oxygen demand 26.0%. (36) • lead 51.2%. (36) • chromium 40.7%.. (36) • copper 21.5%. (36) • iron 52.7%. (36) calcium 17.9%. (36) * lolal suspended solids 84%. (37) Capilal Cost (approximate) $7,600 to $33,560 per unit (23) $10.00010 $40,000 per unit (nol including inslallalion) (23) O&M Cost (approximate) $ 1,000/year per structure (23) Nationwide Examples of Treatment Control (Structural) Best Management Practices (BMPs) Treatment Control (Source) Limilalions Benefils Removal Efficiency Capilal Cosl (approximate) O&M Cosl (approximate) Multi-Chambered Treatment Trains (MCTT) - consist ofa three trealment mechanisms in three different chambers. 1) catch basin - screening process to remove large, grit sized material. 2) settling chamber - removing settleable solids and associated constituents with plale separalors and sorbent pads. 3) media filter - uses a combination of sorption (layers of sand and peat covered by fliter fabric) and ion exchange for the ^pm^^v'll nf *;oIiihle constituents. (21) •high maintenance - require renewing sorbent pads, removing sediment, replacing clogged media. (21) •treals slorm waler al critical source areas with limited space. (21) •loxicily 70% to 100%. (24) • chemical oxygen demand 0%. to 100%. (24) • total suspended solids 70% to 90% (24) • approx. $375,00010 $900,000 (depending on drainage area) Media Fillration - these are usually two or Ihree stage constructed treatment systems, composed of a pretreatment settling basin and a filter bed containing filter media (and a discharge chamber). V 1 J) — Sand Filter - the filler is designed to hold and treat the first one half inch of runoff and the pollutant removal ability of the sand filter has been found to be very good. (3) •not effective Heating liquid or dissolved pollulanis (19) Jl routine maintenance requirement. (19) Jisignificani headloss. (19) Jl severe clogging poientiai. (19) •media may be replaced 3 lo 5 years. (30) •climate condilions may limil filler's performance. (30) Jihigh removal rates for sediment, BOD, and fecal coliform bacleria. (30) •can reduce groundwaier contamination. (30) Jl requires less land, can be placed underground. (19) Jisuilable for individual developmenls. (1) Jiminimum depih of 18 inches. (1) Jl iribuiary areas of up lo 100 acres. (19) • fecal coliform 76%. (30) • BOD 70 %. (30) • lotal suspended solids 70 %. (30) • lotal organic carbon 48%. (30) • lolal nilrogen 21%. (30) • lotal phosphorus 33'/(.. (30) • Lead 45%. (30) • zinc 45%. (30) • iron 45%. (30) •$18,500(1 acre drainage area) (1997). (30) • $6,940 10 $11,600 (less than 1 acre - cast in place) (prorated from 1997 prices using ENR index). (30) • sand filler vault $ 1,790 (prorated from 1997 prices using ENR index). (18) • sand filler basin $3,370 (prorated from 1997 prices using ENR index). (18) • 5 percent of the initial conslruclion cost. (30) Nationwide Examples of Treatment Control (Structural) Best Management Practices (BMPs) TrealmenI Control (Source) Limitations Benefits Removal Efficiency Capital Cost (approximate) O&M Cosl (approximale) Activated Carbon - has long been used in the chemical process industry and in hazardous waste cleanup as an effective method for removing trace organics from a liquid. (3) •heavy maintenance requirement. (19) •severe clogging potential. (19) •limiled by the number of adsorption sites in the media. (3) •small net surface charge and ineffective at removing free hydrated metal ions. (3) •can be placed underground. (19) •less space required. (1) •effective in removing trace organics from liquid. (3) •suitable for individual developments. (1) • $l/lbor$3l5/cy (prorated from 1997 prices using ENR index). (18) Nationwide Examples of Treatment Control (Structural) Best Management Practices (BMPs) TrealmenI Conlrol (Source) Composted Leaves - made from yard waste, primarily leaves, have been advertised lo have a very high capaciiy for adsorbing heavy metals, oils, greases, nulrienls and organic loxins due lo ihe humic conient ofthe compost. (3) Limilalions •heavy maintenance requirement. (19) •severe clogging potential. (19) •in some cases, negative removal efficiencies with increased loads have been reported. (22) Benefils can be placed underground. (19) •no vegetation required. (19) •smaller land area required. (3) •suitable for individual developments. (1) Removal Efficiency • lotal suspended solids 84%. (3),-155% to 72% (22). • pelroleum hydrocarbons 87%(3), 4%. lo64% (22). • chemical oxygen demand 67% (3). 32% to 38%. (22). • lolal Phosphorus 40% (3) & -320% to 28% (22). •TKN-133% to43%. (22) • fecal coliform 6% lo 80%. (22) • oil and grease 0% to 44%. (22) • total petroleum hydrocarbons 33% to 64%. (22) • ammonia 41% lo 64%. (22) • nilrate-172% to 7%. (22) • nilrile -233% lo 29%. (22) • chromium 0% lo 25%. (22) • copper 67% (3) & 4%. lo 9% (22). • zinc 88% (3) & 46% to 65% (22). • aluminum S7%. (3) • nickel 33% to 50%. (22) • lead 0% lo 17%. (22) Capital Cosl (approximale) • $1.30/cy (prorated from 1997 prices using ENR index). (18) • $27,000 to treat 1 cfs (prorated from 1998 prices using ENR index). (22) O&M Cosl (approximate) • $2,400/year (prorated from 1998 prices using ENR index). (22) Nationwide Examples of Treatment Control (Structural) Best Managenient Practices (BMPs) Treatment Conlrol (Souice) Limilations Benefits Removal Efficiency Capital Cost (approximale) O&M Cosl (approximale) Peat Moss - is partially decomposed organic material, excluding coal, lhat is formed from dead plant remains in waier in the absence of air. The physical slructure and chemical composition of peal is determined by the types of plants from which it is formed. Peal is physically and chemically complex and is highly organic. (3) •heavy maintenance requirement. (19) •severe clogging potential. (19) •can have a high hydraulic conductivity. (3) •can be placed underground. (19) •no vegetation required. (19) •smaller land area required. (3) •polar and has a high specific adsorption for dissolved solids. (3) •excellent natural capaciiy for ion exchange. (3) •excellent substrate for microbial growth and assimilation of nulrienls and organic wasle material. (3) $25 lo$105/cy (prorated from 1997 prices using ENR Index). (18) Peat-Sand Filter - man made filtration device, has good grass cover on the lop underlain by twelve to eighteen inches of peat. The peat layer is supported by a 4 inch layer of peat and sand mixture which supported by a 20 lo 24 inch layer of fine lo medium sand. Under Ihe sand is gravel and the drainage pipe. (3) •heavy maintenance requirement. (19) •severe clogging potential. (19) •can be placed underground. (19) •less space required (1) •suitable for individual developmenls. (1) •works best during growing season as grass cover can provide additional nutrient removal. (3) • suspended Solids 90% (3) & 80% (20). • lolal phosphorus 70% (3) & 50% (22). • lolal nitrogen 50% (3) & 35% (20). • BOD 90%. (3) • bacleria 90%. (3) • Irace melals 80%. • lead 60%. (20) • zinc 65%. (20) • COD 55%. (20) $6.50 per cubic fool of malerial (proraled from 1990 prices using ENR index). (20) 7 % of consiruction cosl. (20) (3) Nationwide Examples of Treatment Control (Structural) Best Management Practices (BMPs) Treatment Control (Source) Limilations Benefits Removal Efficiency Capilal Cosl (approximate) O&M Cost (approximale) Waler Quality Inlets - commonly known as oil/grit or oil/waler separators. These devices typically consist of a series of chambers, a sedimentation chamber, an oil separation chamber and a discharge chamber. (31) Useful life is usually 50 years. (20) •limiled drainage area (1 acre or less). (31) •high sediment loads can inlerfere ability to separate oil and grease. (31) •limiled hydraulic and residual slorage. (31) •frequenl mainienancc. (31) •residual may be considered too toxic for landfill disposal. (31) •recommended oil/water separalors be used for spill control as their primary applicalion. (42) •re-suspension of pollulanis. (36) • small tlow capaciiy. (31) •reduction of hydrocarbon contamination. (31) •effectively trap trash, debris, oil and grea.se (31) •ideal for small, highly impervious area. (31) •ideal for maintenance stations. (36) • low land requirement. (20) • sediments 20% to 40%. (31) • efficiency directly proportional lo discharge rale. (31) • total suspended solids 15% to 35%. (20) • total phosphorous 5%. (20) • tolal nilrogen 5% lo 20%. (20) • COD 5%'. (20) • lead 15%. (20) • zinc 5%. (20) $5,900 to $18,900 for cast in place waler quality inlets (proraled from 1993 prices using ENR Index). (31) Catch Basin Inlet Devices - devices that are inserted into storm drain inlets lo tiller or absorb sedimenl, pollutants, and oil and grease (21) • not feasible for larger lhan 5 acres. (20) • high removal efficiency for large particles and debris for pretreatment. (20) • low land requirement. (20) • flexibility for relrofil of exisling systems. (20) Stream Guard Inserts - are sock-type inserts lhal allow collected waler lo filter through Ihe geoiexlile fabric. (21) •maintenance includes removal of sediment and debris. (21) •configured lo remove sedimenl, conslituenls adsorlied lo sediment, and oil and grease. (21) approx. $50,000 to $100,000 per calch basin. (21) Fo.\sil Filler Inserts - are trough-type ol inserts filled wilh granular amorphous alumina silicate media. Removes niiMiii.'inK ihrouuh sorolion. (21) •maintenance includes removal of sediment and debri.s. (21) •configured lo remove sediment, constilucnls adsorbed lo sediment, and oil and grea.se. (21) appix)x. $50,000 lo $100,000 per catch basin. (21) 1 Jv M 1 Ulil • 1 lo 11II V >i.i fill 1 i>\'1 1• \ • 1 OARS™ - is a rubber lype of sorbent insert (34) • free oil and grease 88% to 91%. (39) • emulsified oil and grease 3%. (.39) Nanofihei™ - is a polypropylene adsorbent type of insert. (34) • free oil and grease 86%, 92%, 78%, 85%. (.39) Nationwide Examples of Treatment Control (Structural) Best Management Practices (BMPs) Treatment Control (Source) Limilalions Benefils Removal Efficiency Capital Cost (approximate) O&M Cosl (approximate) Aluminum SUicate: X.wrb™ is made from a natural blend of silica minerals, which when expanded in the unique manufacturing process, makes a white granular material that absorbs spills instantly on contact. Sponge Rok™ - primarily sold as a soil bulking agent (34) • free oil and grease 88%, 91%. 94%. 89%. (39) • emulsified oil and grease 0%. (39) Curb Inlet Drain Diaper Insert - sorbent type diaper placed at the catch basin insert. (40) $125 per unit. (40) Storni Clenz Filter and Multi Cell Flow Through FiV/er - developed by Best Management Technologies, the filters are used typically in maintenance facilities and staging areas were sediment and hydrocarbons are present. (41) • mulli cell flow ihrough filters - $786 to $1233 depending on pipe size (6" lo 12") • slorm clenz filters - $339 to $702 depending on filter insert size. (41) • tlow through filter absorbents $24 to $44 depending on size. • storm clenz absorbents $24 lo $ 54 depending on size. (41) Some Examples ofTemporary Erosion and Sediment Control BMPs activity) (typically used during construction Temporary Seeding of Stripped Areas - The establishment of a temporary vegetative cover on disturbed areas by seeding with rapidly growing plants. This provides temporary soil stabilization lo areas which would remain bare for more lhan seven days where permanent cover is nol necessary or appropriate. (42) •Temporary seeding is only viable when there is a sufficient window in time for plants to grow and establish cover. During the establishment period the bare soil should be proiected with mulch and/or plastic covering. (42) •If sown on subsoil, growth may be poor unless heavily fertilized and limed Because over-fertilization can cause pollulion of stormwater runoff, other practices such as mulching alone may be more appropriale. The potential for over-fertilization is an even worse problem in or near aquatic systems. (42) •Once seeded, areas cannoi be used for heavy traffic. (42) •May require regular irrigation to flourish. Regular irrigation is not encouraged because of the expense and the potential for erosion in areas that are not regularly inspected. The use of low maintenance native species should be encouraged, and planling should be timed to minimize the need tor irrigalion. (42) •This is a lelalively inexpensive form of erosion conlrol bul should only be used on sites awaiting permanenl planting or grading. Those sites should have permanenl measuies u.sed. (42) •Vegetation will not only prevent erosion from occurring, bul will also Irap sediment in runoff from olher parts of the site. (42) •Temporary seeding offers fairly rapid protection to exposed areas. (42) Mulching and Matting - Applicalion of plant residues or other suitable materials 10 the soil surface. This provides immediate protection to exposed soils during the period of short construction delays, or over winter months through the applicalion of plant residues, or other suitable materials, to exposed soil areas. Mulches also enhance plant establishment by conserving moisture and moderating soil temperatures. Mulch helps hold fertilizer, seed, and lopsoil in place in the presence of wind, rain, and runoff and maintains moisture near the soil surface. (42) •Care must be taken to apply mulch al the specified thickness, and on steep slopes mulch must be supplemented wilh netting. (42) •Thick mulches can reduce the soil temperature, delaying seed germination. (42) •Mulching offers instanl piotection 10 exposed areas. (42) •Mulches conserve moisiure and reduce the need for irrigalion. (42) •Neiiher mulching nor mailing require removal; seeds can grow through them unlike plaslic coverings. (42) Plastic Covering - The covering with plastic sheeting of bare areas, which need immediate protection from erosion. This provides immediate temporary erosion protection to slopes and disturbed areas lhal cannot be covered by mulching, in particular during the specified seeding periods. Plastic is also used to protecl disturbed areas, which must be covered during short periods of inactivity to meet November I to March 31 cover requiremenis. Because of many disadvantages, plastic covering is the least preferred covering BMP. (42) •There can be problems with vandals and maintenance. (42) •The sheeting wili result in rapid, 100 percent runoff, which may cause serious erosion problems and/or flooding al the base of slopes unless the runoff is properly intercepted and safely conveyed by a collecting drain. This is strictly a lemporary measure, so permanent stabilization is still required. •The plastic may blow away if it is not adequately overlapped and anchored. (42) •Ultraviolet lighl can cause some types of plastic to become brittle and easily torn. (42) •Plastic must be disposed of al a landfill; il is nol easily degradable in the environment. (42) •Plastic covering is a good method of protecting bare areas, which need immediate cover and for winler plantings. (42) •May be relatively quickly and easily placed. (42) Nationwide Examples of Source Control (Non-Structural) Best Management Practices (BMPs) Source Conlrol (5) Benefit (5) Capital Cost (5) O&M Cosl (5) Minimizing Effects from Highway Deicing Public Education (billing inserts, news releases, radio announcements, school programs) JiCan reduce improper disposal of paints and chemicals. .S200,000/yr(1992) $257,000/yr(1992) Employee Training - leaches employees about slorm water managemenl. potential sources of contaminants, and BMPs. (43) Jilow cosl and easy to implemeni slorm waler management BMPs. (43) Litter Control Jl Reduce potential clogging. Jl proper disposal of paper, plastic und glass. .$20 per trash cans (1992) $16/acre/yr(1992) Recycling Program Jl reduction in potential clogging and harmful discharge. $200.000/yr $350,000 per 300,000 people "No Littering" Ordinance Jl prevents litter from enter storm drain. $20,000 potential self supporting Identify and Prohibit Illegal or Illicit discharge lo Slorm Drain Jihait hazardous and harmful discharge. $2/acre (assumes 1 sysiem monitored every 5 sq. miles) $50/acre/yr (assumes TV inspection) Streel Sweeping - Two types of streel sweepers are available for removal of solids from highway surfaces. The commonly used design is a mechanical street cleaner that combines a rotating gutier broom with a large cylindrical broom to carry the material onto a conveyor bell and into a hopper. The vacuum assisted sweepers, found to potentially remove more fine particles from the impervious surface, are impracticable due lo Iheir slow speed in highway maintenance operations. (42) Jl redudion in potential clogging storm drain malerial. Jisome oil and grease control. N/A $0.83/acre/yr Sidewalk Cleaning Jl reduction of malerial entering slorm drain. N/A $60/acre/yr Clean and Maintain Storm Drain Channels Jl prevent erosion in channel. Jl improve capaciiy by removing sedimentation. Jl remove debris loxic to wildlife. N/A $2 l/acre/yr Clean and Maintain Slorm Inlet and Calch Basins - Inlets, catch basins, and manholes are to be periodically inspected and cleaned out using a vacuum truck. (42) Jl removes sedimentation. Jimay prevent local Hooding. N/A $2 l/acre/yr Snow and Ice Control Operations - Snow conlrol operations consist of removing accumulated snow from the traveled way, shoulders, widened areas and public highway approaches wilhin the right-of-way. (42) Jl removes snow/ice before it requires ice conlrol operations. (42) Clean and Inspect Debris Basin Jl flood control. Jl proper drainage and prevent flooding. N/A $2 l/acre/yr Table References 1. Camp Dresser & McKee, el al. 1993. California Storm Water Best Management Handbook. Prepared for Storm Water Quality Task Force. 4-8:4-77, 5-3:5-69. 2. Scheuler, Thomas R. 1987. Controlling Urban Runoff: A Practice Manual for Planning and Designing Urban BMP's. Prepared for Washington Metropolitan Water Resources Board. 2.11:2.14, 5.1:7.25. 3. Pitt, R. et al. 'The Use of Special Inlet Devices, Filter Media, and Filter Fabrics for the Trealment of Storm Water." 9pp. 4. Eisenberg, Olivieri & Associates. 1996. Guidance for Monitoring the Effectiveness of Storm Water Treatment Best Management Practices. Prepared for the Bay Area Storm Water management Agencies Association. 5-6:5- 7. 5. JMM. 1992 A Study of Nationwide Costs to Implement Municipal Stonn Water Best Management Practices. Prepared for the Water Resources Committee American Public Works Association Southern Califomia Chapter. 4-3:4-14. 6. Maine Department of Environmental Protection. Environmental management: A Guide forthe Town Officials. 16,27. 7. Denver regional Council of Government. Nonpoint Source Demonstration Project. 7:14. 8. Environmental Protection Agency, 1990. Urban Targeting and BMP Selection. 25:31. 9. Strecker, Eric W. 1993. Assessment of Storm Drain Sources of Contaminants to Santa Monica Bay. 21:28, 32. 10. Metropolitan Washington Council of Governments. 1992. A Current Assessment of Urban Best management practices. 1:13. 23:29, 55:69, 105:109. 11. Unocal. "More Down lo Earth Talk from Unocal - Best Management Practices." 12. The Fertilizer Institute. 1985. Symposium: "Plant Nutrients Use and the Environment." 13. The Fertilizer Institute. 1988. Best Management Practices. 14. 1994. Report of the Technical Advison,- Committee for Plant Nutrient Management. 17:18. 15. Virginia State Water Conlrol Board Planning Bulletin 321. 1979. Best Management Practices Handbook: Urban. 111-1:111-9,111-45:111-48, 111-63:111-69,111-163:111-229. 16. California Department of Transportation Environmental Program. 1997. Statewide Storm Water Management Plan. B-14:B-53, C-l:C-22. 17. Caltrans Compost Storm Water Filters (CFSs), Bonita Canyon & North Hollywood Maintenance Yard. 1998. Table 9-15. 18. Minton, Gary R. "Storm Water Treatment by Media Filter." Dec. 11-12, 1997. 19. Ventura Countywide Storm Water Quality Management Program. "Draft Land Development Guidelines." 20. Environmental Protection Agency. 1993. Guidance Specifying Management Measures for Sources of Nonpoint Pollution in Coastal Waters. 21. Caltrans. Storm Water Program. BMP Retrofit Pilot Studies, Technical Information. 1999. 22. Caltrans. Compost Storm Water Filters (CSFs), Bonita Canyon & North Hollywood Maintenance Yard 1997/1998 Wet Season. Post Sampling Summary Repon. 1998. 23. Environmental Protection Agency. 1999. Infiltration Trench. EPA 832-F-99-019. 24. Flan. Daryl R. and Himat Solanki. "Removal Efficiencies of Stormwater Control Structures." 25. Environmental Protection Agency. 1999. Hydrodynamic Separators. EPA 832-F-99-017. 26. Environmenlai Protection Agency. 1999. Storm Water Wetlands. EPA 832-F-99-025. 27. Environmenlai Protedion Agency. 1999. Wet Detention Ponds. EPA 832-F-99-048. 28. Environmenlai Protection Agency. 1999. Infiltration Drainfields. EPA 832-F-99-018. 29. Environmental Protection Agency. 1999. Vegetated Swales. EPA 832-F-99-006. 30. Environmental Protection Agency. 1999. Sand Filters. EPA 832-F-99-007. 31. Environmenlai Protection Agency. 1999. Water Quality Inlets. EPA 832-F-99-029. 32. Environmental Protection Agency. 1999. Modular Treatment Systems. EPA 832-F-99-044. 33. Environmenlai Protection Agency. 1999. Bioretention. EPA 832-F-99-012. 34. Stenstrom, Michael K. and Sim-Lin Lau. "Oil and Grease Removal by Floating Sorbents in a CDS Device." University of California, Los Angeles. 1998. 35. Stormceptor Performance Testing Results, http://www.stormceptor.com/monitor.html Westmount Shopping Centre and Conventry University Testing Results. 36. Caltrans. Highwav Design Manual. Chapter 890 - Storm Water Management. Table 892.3.1999. 37. Allen, Vaikko P. Results from the Vortechs Stormwater Treatment System Monitoring Program at Del-Orme Publishing Company, Yarmouth, Maine. 1998. 38. Environmenlai Protection Agency and American Society of Civil Engineers. National Stormwater Best Management Practices (BMP) Database. Version 1.0, June 1999. 39. Lau, Sim-Lin and Michael K. Strenslrom. "Calch Basin Inserts to Reduce Pollution from Stormwater." Comprehensive Stormwater and Aquatic Ecosystem Managemenl Conference, Auckland, NZ, February 22-26, 1999. 40. Petro-Marine Co. Curb Inlet Drain Diaper Insert. Contact Ronald Isaacson. 28 Buckley Road, Marlboro. NJ 07746. 41. Best Management Technologies Brochure. Contact Rod Butler. 23 Balwin Ave, Crockett, CA 94525. 42. Washington State Department of Transportation. Highwav Runoff Manual. February 1995. 43. Environmental Protection Agency. 1999. Employee Training. EPA 832-F-99-010. 44. Caltrans. El Toro Detention Basin Storm Water Monitoring 1997/1998 Wet Season, Post Sampling Summary Repon. 1998. Caltrans - Best Management Practices Pilot Studies Removal EITiciency % BMPType Site Location Approximate Conslruclion Cosl Drainage Area (acres) Design Slorm (in.) Design Peak Flow (ds) Wcl Season Numbcr of Slorms TSS Nilrale Nilrile Dissolved Phosphorous Tolal Phosphorus TKN Bcnellcial Uses Los Angeles Area Bio Strip - are broad surfaces wilh a full grass cover lhal allows slorm water lo llow in a relatively ihin sheels. Altudcnu Maint Slalion $218,000 1.7 1.0 1.2 N/A N/A N/A N/A N/A N/A N/A N/A RECl, REC2 Infiliralion Trench -a trench is a depression used to ireai small drainage areas by detaining slorm walcr lor shorl periods until it percolates lo the eroundwaler lable. Altudena Mainl Station (buill w/ bio slrip) 1.7 1.0 1.2 N/A N/A N/A N/A N/A N/A N/A N/A RECl, REC2 Bio Slrip I-60.VSR9I $193,000 0.5 1.0 O.I N/A N/A N/A N/A N/A N/A N/A N/A RARE, RECl, REC2, SPWN, WILD, GWR Bio Swale - are vegetated conveyance channels (typically trapezoidal shaped) whecre storm waler llow passes ihrough the grass al a specific dcplh. I-60.VSR9I (built wl bio strip) 0.2 1.0 O.I N/A N/A N/A N/A N/A N/A N/A N/A RARE, RECl, REC2, SPWN, WILD, GWR Bio Swale Cerritos Maint Station $59,000 0.4 1.0 O.I N/A N/A N/A N/A N/A N/A N/A N/A RARE, RECl, REC2, SPWN. WILD, GWR Caltrans - Best Management Practices Pilot Studies Remt )val EITiciency 1 BMPType Sile Localion Approximale Conslruclion Cosl Drainage Area (acres) Design Slorm (in.) Design Peak Flow (ds) Wel Season Numbcr of Slorms TSS Nilralc Nilrile Dissolved Phosphorous Total Phosphorus TKN Beneficial Uses Bio Swale 1-5/1-605 $97,000 0.7 1.0 0.3 N/A N/A N/A N/A N/A N/A N/A N/A RARE. RECl, REC2, SPWN, WILD, OWR Bio Swale 1-60.S/Del Amo Ave $124,000 0.7 1.0 0.2 N/A N/A N/A N/A N/A . N/A N/A N/A RARE, RECl. REC2, SPWN, WILD, GWR Infiltration Basin - a basin is a depression used to ircal larger drainage areas by deiaining slorm waler Ibr short periods until il percolates lo the groundwaier table. I-605/SR9I $273,000 4.2 1.0 0.9 N/A N/A N/A N/A N/A N/A N/A N/A RARE. RECl, REC2, SPWN, WILD, GWR Drain Inlet Insert (Slream guaid)(a) - sock type inserts that allow collecled waler to filler Ihrough the geotextile fabric. Las Flores Mainl Station $88,000 0.2 1.0 O.I N/A N/A N/A N/A N/A N/A N/A N/A WILD Drain Inlet Insert (fossil filler) - trough type inserts filled wilh granular amorphous alumina silicate media. Las Flores Maint Station (buill w/DII (a)) 0.8 1.0 0.2 N/A N/A N/A N/A N/A N/A N/A N/A WILD Drain Inlel Insert (stream guard)(a) Rosemead Mainl Slalion $65,000 0.3 1.0 0.1 N/A N/A N/A N/A N/A N/A N/A N/A WILD, GWR, RECl, REC2, WARM Caltrans - Best Management Practices Pilot Studies ' Rcmc val Elliciency '/ {. BMPType Siie Localion Approximate Conslruclion Cost Drainage Area (acres) Design Slorm (in.) Design Peak Flow (ds) Wel Season Numbcr of Storms TSS Nilrale Nitrile Dissolved Phosphorous Total Phosphorus TKN Beneficial Uses Drain Inlel Insert (fossil filler) Rosemead Mainl Slalion (buill w/Dll (a)) 1.2 1.0 0.5 N/A N/A N/A N/A N/A N/A N/A N/A WILD, GWR, RECl, REC2, WARM Drain Inlet Insert (slream guard)(a) Foolhill Mainl Slalion $68,000 0.2 1.0 0.0 N/A N/A N/A N/A N/A N/A N/A N/A WILD, GWR. MUN, RECl, REC2, WARM Drain Inlel Insert (fossil filler) Foolhill Mainl Slalion (built w/ DII (a)) 1.6 1.0 0.4 N/A N/A N/A N/A N/A N/A N/A N/A WILD, GWR, MUN, RECl, REC2, WARM Exiendcd Detention Basin^ - is a depression lined with either vegclalcd soils or concrele. l-.VI-OO.S Intersection $142,000 6.8 1.0 5.3 1998- 1999 2 -89 to -71 -84 to 23 N/A N/A -84 10 -81 -83 to -92 RARE, RECl, REC2, SPWN, WILD, GWR Exiended Dclcntion Basin* I-60.VSR9I Intersection $137,000 0.8 1.0 1.2 1998- 1999 3 -86 to -58 -54 to 2 N/A N/A 1 ."i lo 222 -8 U) 339 RARE, RECl, REC2, SPWN, WILD, GWR Caltrans - Best Management Practices Pilot Studies Removal Efficiency % BMPType Sile Location Approximate Consiruction Cost Drainage Area (acres) Design Slorm (in.) Design Peak Flow (ds) Wet Season Number of Slorms TSS Nilrale Nitrite Dissolved Phosphorous Tolal Phosphorus TKN Beneficial Uses Media Filter* - designed removes fine sediment and parliculale pollutants through two concrete lined vaults (sedimentation vault and filtering vault). Three filter types 1) Austin - open lopped, 2) Delaware - closed topped, 3) canister - uses pearlite/zeolite media. Eastern Reg. Mainl Sla $341,000 1.5 1.0 1.9 1998- 1999 1 -34 112 N/A N/A 10 108 WILD. GWR, REC2, WARM Media Filler* Foolhill Mainl Station $479,000 1.8 1.0 3.0 1998- 1999 2 -42 lo -34 285 10 289 N/A N/A -7 to 83 42 to 140 WILD, GWR, MUN, RECl, REC2. WARM Media Filter Terminatio n Park & Ride $450,000 2.8 1.0 3.6 N/A N/A N/A N/A N/A N/A N/A N/A RARE. RECl, REC2, SPWN, WILD, GWR Media Filter Paxton Park& Ride $331,000 1.3 1.0 1.7 N/A N/A N/A N/A N/A N/A N/A N/A GWR, REC2 r Caltrans - Best Management Practices Pilot Studies Removal Efficiency % BMP Type Sile Location Approximate Construciion Cost Drainage Area (acres) Design Slorm (in.) Design Peak Flow (ds) Wel Season Number of Slorms TSS Nilrale Nitrite Dissolved Phosphorous Total Phosphorus TKN Beneficial Uses Multi-Chambered Treatment Train - Three chamber mechanism I) catch basin, which functions primarily as a screening process, 2) settling chamber, which removes settleable solids with plale separalors and sorption pads, 3) media filter, which uses a combinaiion of sorption (through layers of sand and peat covered by filler malerial) and ion exchange. Via Verde Park& Ride $375,000 l.l .0 N/A N/A N/A N/A N/A N/A N/A N/A WILD, WET, GWR, RECl, REC2, WARM Mulli-Chambered TrealmenI Train Metro Maint Slalion $893,000 4.6 6.6 N/A N/A N/A N/A N/A N/A N/A N/A GWR, RECl. REC2, WARM Mulli-Chambered Trealment Train Lakewood Park & Ride $456,000 1.0 N/A N/A N/A N/A N/A N/A N/A N/A RARE, RECl, REC2, SPWN, WILD, GWR Caltrans - Best Management Practices Pilot Studies Removal Efficiency % BMPType Site Location Approximate Conslruclion Cosl Drainage Area (acres) Design Storm (in.) Design Peak Flow (ds) Wet Season Number of Slorms TSS Nitrate Nilritc Dissolved Phosphorous Tolal Phosphorus TKN Beneficial Uses Continuous Dellection Separator - a pre casl underground unit placed downstream of freeway drain inlcls lo capture sedimenl and debris. The unit creales a vortex of water lhal allows waler lo escape thiough screens, while contaminants are deficcted into a sump, and later removed. 1-210/Orcas Ave $62,000 l.l 1.0 0.3 N/A N/A N/A N/A N/A N/A N/A N/A WILD, GWR, RECl, REC2, WARM Continuous Defiection Separalor 1- 210/Filmor e Sl $63,000 2.5 1.0 0.6 N/A N/A N/A N/A N/A N/A N/A N/A WILD, GWR, RECl, REC2. WARM Media Filler (compost)'^ N. Hollywood Maint Sta $40,000 3.0 0.7 1.0 1997- 1998 5 -155 7 29 38 28'* 43 Media Filler (compost)'^ Bonita Canyon 1.7 0.8 6,0 1997- 1998 5 72 -172 -233 -1633 -320 -133 Exiended Detention Basin " El Toro 68 0.8 30.4 1997- 1998 5 88 15 61 22 57 40 RARE, RECl, REC2, SPWN, WILD, GWR San Diego Area Caltrans - Best Management Practices Pilot Studies Removal Efficiency ^ I. BMPType Sile Localion Approximale Constnidion Cost Drainage Area (acres) Design Slorm (in.) Design Peak Flow (ds) Wel Season Number of Slorms TSS Nilrate Nilrile Dissolved Phosphorous Total Phosphorus TKN Beneficial Uses Exiended Detention Basin 1- .VManchesl er (east) $369,000 4.8 1.3 4.6 N/A N/A N/A N/A N/A N/A N/A N/A RECl, REC2, BIOL, EST, WILD, RARE, MAR, MIGR Extended Dcienlion Basin I-.VSR56 $166,000 5.3 1.3 5.7 1998- 1999 5 23 10 80 -100 10 64 -65 to 68 -84 to 43 BIOL, EST, MAR, MIGR, RARE, RECl, REC2, SHELL, WILD Extended Detention Basin I-I.VSR78 $855,000 13.4 1.9 9.5 1998- 1999 4 45 to 72 -240 to 58 -299 10 -62 -IOI to 19 AGR, COLD. MUN, RECl, REC2. WARM, WILD Infiliralion Basin l-5/La Cosia (wesl) $241,000 3.2 1.3 3.0 N/A N/A N/A N/A N/A N/A N/A N/A BIOL. EST, MAR, MIGR, RARE, RECl, REC2, WARM Caltrans - Best Management Practices Pilot Studies Removal Efficiency % BMPType Site Location Approximate Construction Cosl Drainage Area (acres) Design Storm (in.) Design Peak Flow (ds) Wcl Season Number of Slorms TSS Nilralc Nilrile Dissolved Phosphorous Total Phosphorus TKN Beneficial Uses Wcl Basin - a basin consisting ofa permanenl pool of waler surrounded by a variety of wetland plant species. l-.VLa Costa (east) $694,000 4.2 1.3 2.2 N/A N/A N/A N/A N/A N/A N/A N/A RECl, REC2, BIOL, EST, WILD, RARE, MAR, MIGR Media Filler (pearolile/zeolite) Kearny Mesa Maint Sla $340,000 1.5 09 2.7 1998- 1999 3 -27 to 20 5 to 29 -115 10 46 5 10 32 REC2, WARM, WILD Media Filter (sand type 11) Escondido Maint Station $451,000 0.8 1.0 2.2 1998- 1999 3 Olo 66 II 10 70 -23 to 70 56 10 84 MUN. AGR, RECl, REC2, WARM COLD, WILD Media Filler (sand lype 1) La Cosia Park & Ride $242,000 2.8 0.9 2,3 1998- 1999 3 54 10 98 -98 to 4 -113 to 26 -28 lo 38 BIOL, EST, AMR, MIGR, RARE, RECl, REC2, WARM Media Filter (sand type 1) SR78/1-5 Park& Ride $231,000 0.8 1.0 2,7 1998- 1999 2 54 -313 • -7 lo 28 7 to 11 BIOL. MAR, RARE. RECl, REC2, WARM, WILD Bio Swale SR78/Melr ose Dr $156,000 2.4 1.2 6.1 N/A N/A N/A N/A N/A N/A N/A N/A AGR, OMD, RECl. REC2, WARM, WILD Caltrans - Best Management Practices Pilot Studies Removal Efficiency % BMPType Site Location Approximate Conslruclion Cosl Drainage Area (acres) Design Slorm (in.) Design Peak Flow (cfs) Wel Season Numher of Storms TSS Nilrale Nitrile Dissolved Phosphorous Tolal Phosphorus TKN Beneficial Uses Bio Swale 1-5/Palomar Airport Rd $142,000 2.3 N/A 3.8 N/A N/A N/A N/A N/A N/A N/A N/A REC2, WARM, WILD Bio Slrip Carlsbad Mainl Sla (wesl) $196,000 0,7 N/A 1.3 N/A N/A N/A N/A N/A N/A N/A N/A REC2, WARM. WILD Infiliralion Trench/Strip Carlsbad Maint Sta (east) (buill w/ bio slrip) 1.7 1.3 2.9 N/A N/A N/A N/A N/A N/A N/A N/A REC2, WARM, WILD ' Caltrans. Compost Storm Water Fitters (CSFs), Bonita Canyon & North Hollywood Maintenance Yard, Slorm Water Monitoring. 1998.' Caltrans. El Toro Detention Basin. Storm Water Monitoring. 1998. Dissolved Phosphorus higher lhan Tolal Phosphorus concenlrations. due lo results from slorm 4. Without storm 4, efficiencies are -36% for dissolved phosphorus and 7% for lotal phosphorus. N/A - Nol Available at ihis lime. • Preliminary Informaiion. APPENDIX 3 Mitigation Flowrate and Volume Calculation Tables T:\Water Resoiirces\1325-Biessi-Pointsetiia\Water Quality\1325WQ-city.(loc TABLE 7. REQUIRED MITIGATION FLOWRATE AND VOLUME CALCULATIONS Location AREA (Ac) Planning Areas Qm (cfs) Vm (ft') Vm (cy) CDS Device No. A 166.1 PAS, 7-9,12-14, 15b 21.0 361763 13399 PSWC 56_68 B 11.0 PAIId 1.2 23958 887 PMSU 20 20 C 7.0 PAIIc 0.8 15246 565 PMSU 20 15 D 12.0 PAIIb 1.3 26136 968 PMSU 20 20 E 12.0 PAIIa 1.3 26136 968 PMSU 20 25 F 135.0 PA3b, 4, 6,10,15a 19.9 294028 10890 PSWC 56 68 G 75.0 PA 6,10, 15a 8.5 163349 6050 PSW 50 42 H 2.3 PAI 0.4 5009 186 PMSU 20 15 1 21.9 PA2 4.2 47698 1767 PMSU 40 40 J 25.5 PA3a 4.8 55539 2057 PMSU 40_40 K 21.0 PA3b 4.0 45738 1694 PMSU 40 40 L 39.0 PA4 7.4 84941 3146 PSW 50 42 M 31.0 PAS 5.9 67517 2501 PMSU 40 40 N 1.0 PAI 4 0.2 2178 81 PMSU 20_1S 0 13.0 PAI 3 1.4 28314 1049 PMSU 20_2S P 92.1 PA7, 8, 9, 12a 10.1 200592 7429 PSW 50 42 0 15.0 PAI 2b 1.7 32670 1210 PMSU 20_2S Planning Area Land Use AREA (Ac) 0 1 Qm (cfs) Vm (ft') Vm (cy) PAI Industrial 2.3 0.95 0.2 0.4 5009 186 PA2 Industrial 21.9 0.95 0.2 4.2 47698 1767 PA3a Industrial 2S.S 0.95 0.2 4.8 55539 2057 PA3b Industrial 21.0 0.95 0.2 4.0 45738 1694 PA4 industrial 39.0 0.95 0.2 7.4 84941 3146 PAS Industrial 31.0 0.95 0.2 5.9 67517 2501 PA6 Residential 19.0 0.55 0.2 2.1 41382 1533 PA7 Residential 22.7 0.55 0.2 2.5 49440 1831 PAS Residential 22.4 0.55 0.2 2.5 48787 1807 PA9 Residential 34.0 0.55 0.2 3.7 74051 2743 PAID Residential 34.0 0.55 0.2 3.7 74051 2743 PAIIa Residential 12.0 0.55 0.2 1.3 26136 968 PAIIb Residential 12.0 0.55 0.2 1.3 26136 968 PAIIc Residential 7.0 0.55 0.2 0.8 15246 565 PAIId Residential 11.0 0.55 0.2 1.2 23958 887 PAI 2a Residential 13.0 0.55 0.2 1.4 28314 1049 PAI 2b Residential 15.0 O.SS 0.2 1.7 32670 1210 PAI 3 Mixed Use 13.0 0.55 0.2 1.4 28314 1049 PAI 4 Industrial 1.0 0.95 0.2 0.2 2178 81 PAI 5a Mixed Use 22.0 0.6 0.2 2.6 47916 177S PAI 5b Mixed Use 14.0 0.6 0.2 1.7 30492 1129 1. Qm = A X C X I = Peak discharge to be mitigated 2. Vm = 0.6in x A = Volume of runoff to be mitigated 3. 135,000 cu ft retention available In OS-1 basin (Location G on Exhibit Map) witti 2 feet freeboard. APPENDIX 4 Construction BMPs T:\Water Resources\1325-Bressi-Pomlsettia\Water Quality\1325WQ-city.doc 4. BMPs FOR CONTRACTOR ACTIVITIES INTKODUCnON ' This chapter describes specific Best [ '' ' " Management Practices (BMPs) for common consiruction activities lhat may poUute storm waier. Chapter 2 led you ihrough Ihe steps of identifying activities at your sile lhat can pollute storm water, while Chapter 3 provided guidance on BMP selection. This chapter will provide a list of BMPs lhat can be used to fit your site's needs. BMP fact sheels are provided for each of the contraclor's activities, noted in the box. are consistent wilh Worksheet 4 in Chapter 2. Each fact sheel contains a cover sheet wilh: A description of the BMP Approach Requirements Costs, including capital costs, and operation and maintenance (O&M) costs Maintenance (including administrative and staffing) Limilalions References The side bar presents informalibrt; on which BMP objective applies, targeted constituents; and an indication of thc level of effort and costs to implement. For some BMPs, further informaiion is provided in additional sheets. Contractor Activities Construction Practices CAI Dewatering Operaiions CA2 Paving Operaiions CA3 Siruclure Construcuon and Painting Material Management CAIO Material Delivery and Storage CAII Material Use CAI2 Spill Prevenlion and Control Waste Management CA20 Solid Waste Management CA2I Hazardous Waste Management CA22 Conlaminaied Soil Management CA23 Concrete Waste Management CA24 Sanitary/Septic Waste Managemenl Vehicle and Equipment Management CA30 Vehicle and Equipment Cleaning CA3I Vehicle and Equipment Fueling CA32 Vehicle and Equipmerit Maintenance Contractor Training CA40 Employee/Subcontractor Train'ing These BMP fact sheets are suitable for inclusion in many storm water pollulion prevention plans for typical contractor activities. Thc BMPs listed are not an exhaustive list, nor will every BMP be appropriate for every situation. Therefore, suggested BMPs which arc inappropriate may be deleted and additional BMPs for specific sile conditions should be added. In addition, your selection and implementation of BMPs should be reviewed on a regular basis to match the changing conditions at conslruclion sites. Construction Handbook 4 - 1 March, 1993 o o e o C o a X L> 3 CL TABLE 4.1 CONTRACTOR ACTIVITIES AND DMP OBJECTIVES I BMP OB,JECTIVES BMP CATEGORY PRACTICE GOOD HOUSE- KEEPING CONTAIN WASTE MINIMIZE DISTURBED AREA STADILIZE DISTURBED AREA PROTECT SLOPES AND CHANNELS CONTROL SITE PERIMETER CONTROL INTERNAL EROSION CAOl Construction Practices Dewatering Operations / / / / CA07 / , rA03 Structure Construciion and Painting / / Material Management / CAIO CAII Material Delivery and Storage Material Use / / / CA12 Spill Prevention and Control Waste Management V rA70 Solid Waste Manni;emcnt / CAI 1 Hazardous Waste Manngemcnt / v., r\ ^ 1 Contaminated Soil Management / / / CA23 Concrete Waste Managetnent / / CA24 Sanitary/Septic Waste Management Vehicle and Elauloment Manacemei it V rA30 Vehicle and Equipment Cleaning / / / rA31 Vehicle and Equipment Fueling / CA32 Vehicle and Equipment K/alnf^nanrft / Cnnlrartnr Tralnino Pmnlovee/Subcontractor Training 1 / / 1 .u 2 n ACTIVITY: DEWATERING OPERATIONS Curb Vibt Protection (for scdimcnt-ladcn waters) Stmn Pram Objectives Contain Waste UinimizB Disturbod ATMS St^bilizB Disturbed Areas PrvtKt Slopes/Cti^^iT) C^^itnA Site P^rirw^ Control internal Erosion DESCRIPTION Prevent or reduce the discharge of pollutants to siorm water from dewatering operations by using sediment controls and by testing lbc groundwaier for poUotion. APPROACH There arc two general classes of pollutants lhat may result from dewalenog operations; sediment, and toxics and petroleum producis. A high sediment coDtent in dcwaiering discharges is common because of the nature of ibe operauoo. On the other band, toxics and petroleum producis arc not commonly found in dewaicring discharges unless, the site or surrounding area bas been used for ligbi or heavy industrial activities, or the area bas a bisioty of groundwaier contamination. Tbe foUowing steps wUl bclp reduce storm water poUution from dewaicring discharges: ^tdimcnt • Use sediment controb to remove sediment from waier gencralcd by dewatenng (Sec Sediment Trap (ESC 55) and Sedimenl Basin (ESC 56) in Chapter 5). Usc nitration to remove sediment from a sedimenl trap or basm. Filuatioa can bc achieved with: Sump pil and a perforated or slit standpipe witb holes and wrapped in fdter fabric. Tbe standpipe b surrounded by slooes which fillers the water as it collects in tbe pit before being pumped ouLWrappmg the standpipe in filler fabric may require an increased suctioo inlet area lo avoid clogging and unac- ceptable pump operation. Floating suction hose to altow cleaner surface water lo be pumped out Tntics and Pefroleum Products In areas suspected of having groundwater pollution, sample Ibe groundwaier near lbc excavation site and bave the water tested for known or suspected pollutants at a certified laboratory. Qjcck with the Regioual Water Quahty Control Board and the local wastewater treatment plant for dieir requirements for dcwaa^iing, additional water quality tests, and disposal options. . With a permit from the Regiooal Walcr Quality Control Board, you may bc able to rtcycle/rcusc pumped groundwater for landscape irrigation, or discharge to tbe stonn sewer. With a permit from tbe local agency, you may be able to treat pumped groundwater and discharge it to tbe municipal wastewater treatment plant via the sanitary sewer. For a quick reference on disposal alternatives for specific wastes, sec Table 4.2, CA40, Employec/Subooncraaor Training. Targeted Pollutants 9 Sediment O Nutrients O Toxic Materials O Oil A Grease O Floatable Materials O Other Coristruction Waste W Ukoly to Hav* Significant Impact O Prottabia Low of Unkrtown Impact Implementation Requirements O CapHal Costs Q OLM Costs Q Maintenance ^ Training O Suitability for Slopes >5% High O Lour CM Best Management Practices^ Construction Handbook 4 - 3 March, 1993 CONTRACTOR ACTIVITY: DEWATERING OPERATIONS (Continue) REQUIREMENTS . Costs (Capilal, O&M) - Sediment controls are low cosl measures. Treatment and/or discharge of polluted gnaondwaler can be quite expensive. Maintenance „ ^, ^, . \ - Maintain sedimenl controls and filters in good working order. (Sec Chapter 5 for details) Inspect excavated areas daily for signs of contaminated water as evidenced by discolorauon, oily sbecn. or odors. J'^m ^^I!^ of contaminated waler may mdicate contammated soil as well. See CA22 (Contammated Soil Man- agement) in Ibis chapter for more information. S^^ci?^>^ Bay-Consuucuon-Rclated Industries: Best Management PracUces for Storm Water PoUution Prevention; SanU Oara VaUey Nonpoint Source PoUution Coouol Program. 1992. Storm Water Management for Construction Activities, Developing Pollution Prevention Plans and Best Managemenl Practices, EPA 832-R-92005; USEPA, April 1992. CAI Consfruction Handbook 4-4 March, 1993 Graphic: North CenUal Texas COG. 1993 Objectives ; DESCRIPTION Prevent or reduce tbe discharge of pollutants from paving operauons, using measures to I prevent runon and ninoff poUution, properly disposmg of wastes, and traming employees I and subcontractors. APPROACH Avoid paving during wet weather. , r- A m Store materials away from drainage courts to prevent storm water runon (see CA 10 Material Delivery and Storage). Proiea drainage courses, particularly in areas with a grade, by employing BMPs to divert lunoff or U^ap/filler sediment (see Chapter 5). Leaks and spills from paving equipmeni can conlain loxic levels of heavy metals and oil and grease. Place drip pans or absorbent materials under paving equipment when not in use Clean up spills with absorbent materials rather than bunrmg. See CA32 (Vehicle and Equipment Maintenance) and CA12 (SpUl Prevention and Control) m this chapter. Cover catch basins and manholes when applying seal coat, tack coat, slurry seal, fog seal, etc. . • .t Shovel or vacuum saw-cut slurry and remove from site. Cover or bamcade storm drains during saw cutting to contain slurry. If paving involves portland cement concrele, see CA23 (ConcrcU: Waste Manage- ment) m Uiis chapter. If paving involves asphaltic concreie, foUow these steps: - Do not allow sand or gravel placed over new asphalt to wash into stonn drams, streets, or creeks by sweeping. Properly dispose of this waste by refernng to CA20 (SoUd Waste Management) in this chapter. - Old asphalt must be disposed of profx;rly. Collect and remove aU broken asphalt from thc site and recycle whenever possible. - If paving involves on-site mixing plant, foUow the stonn water penniiung rcquucments for mdustrial activities. Train employees and subcontractors. REQUIREMENTS • CosU (Capital, O&M) All of tbe above arc low cost measures. • Maintenance - Inspect employees and subcontractors to ensure thai measures are being followed - Keep ample supplies of drip pans or absorbent matenals on-site. LIMFFATIONS • There arc no major hmitauons to this best management pracUce. (^^o^ekeeping Practiced) Conlain Wasle Minimize Disturbed Areas Stabilize Disturbed Areas Protect Slopes/Channels Control Site Perimeter Control Internal Erosion Targeted Pollutants Q Sediment O Nutrients Q Toxic Materials Q Oil & Grease O Floatable Materials O Other Construction Waste # Ukely to Hava Slgnincanl Impact O Probabta Low or Unknown Impaci Implementation Requirements O Capital Cos(5 O OiM Costs O Maintenance Training O Suitability lor Slopes >S% High O Low Best Manageme Practices' nt Construction Handbook 4 - 5 March, 1993 CONTRACTOR ACTIVITY: PAVING OPERATIONS (Continue) REFERENCES r> . c ..r r> ,. Blueprint for a Ckan Bay-Constnjciion-Rclaicd Industries: Best Managemenl Pracuccs for Stonn Water PoUuuon Prevention; Santa Clara Valley Nonpomt Source Pollulion Conlrol Program, 1992. Hol-mu Asphalt Paving Handbook, U.S, Anny Corps of Engmeers, AC 150/5370-14, Appendix 1, July 1991. Consfruction Handbook 4-6 March, 1993 ACTIVITY: STRUCTURE CONSTRUCTION AND PAINTING Objectives Graptiic: Honh Central Texas COG. 1993 DESCRIPTION Prevent or reduce lbc discharge of pollutants to stonn waler from stmcture conslnicuon and painting by enclosing or covering or beraiing building malerial storage areas, using I good bousekeepmg pracdces. using safer alternative products, and trainuig employees and subcontractors. APPROACH . - . r c .K^ - Keep the work site clean and orderly. Remove debns in a umely fashion. Sweep the Use soil erosion control techniques if bare ground is exposed (See Chapter 5). Buy recycled or less hazardous products to tbe maxunum extent practicable. Conduct painting operations consistent with local air quality and OSHA regulations. Properiy store paints and solvents. See CAIO (Material Delivery and Slorage) in ihis chapter. Properly store and dispose waste maierials generated from the acuviiy: Sec the wasle management BMPs (CA20 to CA24) in this chapter. Recycle residual paints, solvents, lumber, and olher materials to the maximum extent practicable. Make sure lhat nearby slorm drains arc well marked to mmunize thc chance of inadvcitent disposal of residual paints and other hquids. Clean lbc stonn drain system in the immediaie consuuction area after constnicuon is completed. Educate employees who are doing the work. Infonn subcontraclors of company policy on these matters and include appropnate provisions in their conuaci to make certain proper housekeepmg and disposal practices are implemented. Fora quick reference on disposal alternatives for specific wastes, see Table 4.2. CA40. Employec/Subcontracior Training. REQUIREMENTS . Costs (Capital O&M) - These BMPs are generally of low to moderate cost • Maintenance Maintenance should t>e minunal. LIMITATIONS - Safer altcmauve products may not bc available, suitable, or effecuve m every case. Hazardous waste lhat cannoi bc re-used or recycled must bc disposed of by a licensed baiardous waste hauler. Housekeeping Prances) Contain Waste Minimize Disturbed Areas StabiTtze Disturbed Areas^ Protect Slopes/Channels Control Site Perimeter Control Internal Erosion Targeted Pollutants O Sediment O Nutrients Q Toxic Materials O Oil & Grease # Floatable Materials 9 Other Construction Waste # Ukely to Hava Significant impact O Probable Low or Unknown Impact Implementation Requirements O Capital Costs O OiM Costs O Maintenance ^ Training O Suitability for Slopes >S% High O Low CA3 Best^ Management Practices'^ Construction Handbook 4 - 7 March, 1993 ACTIVITY: STRUCTURE CONSTRUCTION AND PAINTING (continue) Be cenain that actions to help stonn water quality are consistent with Cal- and Fed-OSHA and air qualily regula- tions. n^iiniinP activities can generate poUutants that can reach slonn water if proper care is nol taken. Tbe S:i"Xrc - " sclents, pSls. paint and vamish removers, finishing residues, s^nt thinners, :^;" e^e?s kerosene, asphalt and concrete materials, adhesive residues, and old asbestos insulauon. For speafic information on some of these wastes see Ibe following BMPs in this chapter CA20 Solid Waste, CA21 Hazardous Waste, and CA23 Concreie Waste. More specific infonnation on structure construction practices is listed below. future, employ tbe appropriate soil erosion and control techniques described m Chapter 5. Sj^>pn/S?miiafV ^rw*^ ^"""cctions ^y^-- Cross connections between tbe sanitary and s^ drain systems, as w^U ri^roSer^nnrtion's into the drLage sysiem from inside a building, arc illegal. Color code or Hag pipelmes on Ibe projecl site to prevent such connections, and train construcuon personnel. fS^ pollution regulations may, in many areas of tbe slate, specify painting procedures which if properly canied out t^usuX^fficient to protect stL water quality. Tbesc regulations may require that painUng operaUons be prc^ y ^loidi covered to avoid drift Use temporary scaffolding to bang drop cloths or drapenes to preven. ""f^ ^P^^^ tion tq'.pment that minimizes overspray also helps. When using sealants on wood, pavement, roofs, etc. quKkly clean up spiUs. Remove excess Uquid wilh absorbent matenal or rags. If painting requues scraping or sand blasting of the existing surface, use a drop clotii to collect most ^^ips. Dis^Tt^e residue pro^rly. If the paint contains kad or iributyl tin, it is considered a hazardous waste. Refer to tbe waste management BMPs in Uiis chapter for more mfonnauon. Mix paint indoors, in a containment area, or in a flat unpaved area nol subject to significant erosion Do during ^w^r because Cleanup ofaspU. WUl never be 100% effective. Dried paint wm washed away by stonns If using water based painty clean tbe appUcauon equipment ID a sink that is connected to U|c sTwer i inTcontainm^t area wbere the dried paint can be readily removed. Properly store kftover paints if ibcy are to be kept for thc next job, or dispose of properly. ^^Sking on roofs, if small particles have accumulated in thc guuer. either sweep out the guner ^ ^^^^^^ ^^pr^L^cirai the oulktTa>e downspout A sock or geofabric placed over the outiet nuy effccuv^y ^ ^.Ss IfTdotnspout -IS l-med tight, place a temporary plug at the fust convenient point in the stonn dram and pump out tbe water witii a vactor Uuck. and clean thc catch basm sump where you placed the plug. ^u^^'J^To^a'^lean Bay-Constniction-Related Industries: Best Management Practices for Stonn Water PoUution Prevenlion; Santa Oara Valley Nonpoint Source PoUution Conuol Program, 1992. • CA3 Consfruction Handbook 4 - 8 March, 1993 ACTIVITY: MATERIAL DELIVERY AND STORAGE Objectives Contain Waste Minimize Disturbed Areas Stabilize Disturbed Areas Protect Slopes/Channels Control Site Perimeter Control Intemal Erosion DESCRIPTION ^ . i Prevent or reduce Uie discharge of pollutants to stonn water from matenal delivery and stoiaPC by minunizing Uic storage of hazardous materials on-site, stonng matenals ui a designated area. instaUing secondary conlainment, conducting regular mspecuons, and iraining employees and subcontractors. Tbis best managemenl practice covers only material deUvery and storage. For other infonnation on materials, see CAI 1 (Material Use), or CA12 (SpiU Prevention and 1 Control). For infonnation on wastes, sec Uie waste management BMPs in this chapter. I APPROACH I The foUowing materials are commonly stored on consuucuon sues: Soil. Pesticides and herbicides, FertiUzers, Detergents, Plaster or other producis. PeU^oleum pnsducts such as hiel, oil. and grease, and OUier hazardous chemicals such as acids, lime, glues, paints, solvents, and curing compounds. I Storage of these materials on-site can pose Uic following risks: Storm water poUution, Injury to workers or visitors. Groundwater poUution. and Soil conlaminaiion. I Therefore, Uie foltowing steps should be taken to mmunizc your risk Designate areas of Uic constniction site for material delivery and storage. - Place near die constmction entrances, away from waterways - Avoid transport near drai nagc paths or waterways - Surround wiUi canb berms (see ESC30, Earth Dike.) Place "m an area which wiU bc paved Stotage of reactive, ignitable, or flammable liquids must comply wiUi Uic fue codes of your area. Contaa Uie local Rre Marshal to review site materials, quanUUes. and proposed storage area to detennine specific requirements. Sec Uie Hammabk and Combustible Liquid Code, NFPA30. For a quick reference on disposal alternatives for specific wastes, see Table 4.2. CA40, Employee/Subcontractor Training. Keep an accurate, up-to-date inventory of materials delivered and stored on-site. Keep your inventory down. Targeted Pollutants O Sediment O Nutrients O Toxic Materials Q Oi7 & Grease Q Floatable Materials O Other Constmction Wasle # Ukely lo Have Slgnincanl Impact O Probable Low or Unknown Impact Implementation Requirements O Capital Costs O O&M Costs O Maintenance ^ Training O Suitability for Slopes >S% High O Low ll CA10 Besr Management Practices^ Construction Handbook March, 1993 ACTIVITY: MATERIAL DELIVERY AND STORAGE (continue) Minimize hazardous uiaterials on-site slorage. Handle hazardous materials as infrequentiy as possible. •A , c.r^r^no maierials in a covered area. Store materials in secondary containments ""t^ r I^'enT^e^rtug™^^^ POO. for non-reactive materials such as detergents, S gre^.^ra-- sS-oun. of matenal may be secondanly contained m "bus boy" trays or concrete Sitot MI'chemicals, drums, or bagged materials directiy on die ground. Place Uiese items on a pallet and. when Dossible.in secondary containment. . A U dmms must be kept uncovered, store Uiem at a slight angle to reduce ponding of ramwater on Uie hds and to reduce conosion. „ . ^ , . Try to keep chemicals in Uieu original containers, and keep Uiem well labeled. Train cmDlovees and sut>conuaciors- . Employees Lned in emergency spUl cleanup procedures should be present when dangerous matenals or hquid chemicals are unloaded. . , . . If significant residual materials remain on Uie ground after constmction is complete, properly remove matenals a^ lly'c^nl^natl^^uXc CA22). If Uic area is to be paved, pave as soon as materials arc removed to stabilize Uie soil. REQUIREMENTS • Cost (Capital, O&M) All of Uie above are low cost measures. Maintenance - Keep Uie designaied storage area clean and well organized. - Conduct routine weekly mspections and check for extemal conosion of matenal containers. - Keep an ample supply of spiU cleanup materials near Uie storage area. LIM rr ATIONS Slorage sheds often must meet building and fire code requirements. S^a'^getl^nl Practices and Erosiori Control Manual for Consuuction Sites; Flood Conlrol DisUict of Maricopa Couniy, AZ, September 1992. Pollution Control Program, 1992. Coastal Nonpomt Pollution Control Program: Program Development and Approval Guidance, Working Group Working Paper, USEPA, April 1992. Stonn Water Management for Construction Activities; Devetopmg Pollution Prevention Plans and Besl Management Practices, EPA 832-R-92005; USEPA, April 1992. i CAIO Consfruction Handbook 4 - 10 March, 1993 ACTIVITY: MATERIAL USE Graphic: htorth Central Texas COG. 1993 DESCRIPTION Prevent or reduce the discharge of poUutants to storm walcr from material use by using alternative products, minimizmg hazardous material use on-site, and trainmg employees and subconiraaors. APPROACH Tbe foUowing materials are commonly used on consuuction sites: Pesticides and herbicides, FertiUzers, Detergents. Plaster and oUier products. Peuoleum products such as fuel, oil, and grease, and Other hazardous chemicals such as acids, lime, glues, paints, solvents, and curing compounds. Use of these materials on-site can pose the followmg risks: Storm water poUution. Injury to workers or visitors. Groundwater poUution. and • Soil contamination. Therefore. Uie foltowing steps should be taken to mmunizc your risk: Use less hazardous, alternative materials as much as possible. Mininuzc use of hazardous materials on-site. Use materials only where and when needed to complete the construction activity. Foltow nunufaclurer*s instructions regarding uses, protective equipment, ventilation, flammabiUty, and mixing of chemicals. Personnel who use pesticides should be trained in ihcir use. Tbe Cahfoniia Depart- ment of Pesticide Regulation and county agricultural commissioners Ucense pesticide dealers, certify pesticide appUcators, and condua on-site inspections. • Do not over-apply fertilizcis, herbicides, and pesticides. Prepare only Uie amount needed. Follow Uie reconunended usage instmctions. Ovcr-appUcation is expensive and environmentaUy harmful. Unless on sleep slopes. tiJl fertilizers into the soil rather Uian hydroseeding. Apply surface dressings in several smaUer appUcations, as opposed to one large appUcation. to aUow time for 'mfiltration and lo avoid excess malerial being carried off-site by mnoff. Do not apply Uiese chemicals just before it rains. • Train employees and subcontractors in proper material use. Objectives Housekeeping Practices, Contain Waste Minimize Disturbed Areas Stabilize Disturbed Areas Proiect Slopes/Channels Control Site Perimeter Control Internal Erosion Targeted Pollutants O Sediment O Nutrients O Toxic Materials OU A Grease O Floatable Materials O Other Construction Waste # Ukely to Have Significant Impact O Probable Low or Unknown Impact Implementation Requirements O Capital Costs O OAM Costs O Maintenance Q Training O Suitability for Slopes >5% High O Low CA11 Best' Management Practices'^ Construction Handbook 4 - 11 March, 1993 Consfruction Handbook 4 - 12 March, 1993 ACTIVITY: SPILL PREVENTION AND CONTROL Objectives •mm m C^^^^i^ekeeping Practicep Contain Waste Minimize Disturbed Areas Stabilize Disturbed Areas Protect Slopes/Channels Control Site Perimeter Control Intemal Erosion DESCRIPTION Prevent or reduce Uic discbarge of poUutanU to stonn water from leaks and spUls by ISucing Uie chance for spills, stopping Uie source of spiUs. containmg and cleanmg up spiUs. properly disposmg of spUl materials, and training emptoyees. Ibis best management praOicc covers only spdl prevention and control. However, CAIO fljLria^ Delivery and Storage) and CAI I (Material Use), also contam usehil mfonna- tion ^cularly on spiU prevention. For infonnation on wastes, see Uie waste manage- ment BMPs in Uiis chapter. I APPROACH Tbe following steps wUl help reduce Uie stonn water unpads of leaks and spdls: ' ^^"^SSSSf^llute in different amounts. Make sure Uial each employee knows what a "significant spiU" is for each material Uicy use. and what is Uic appro- priate response for "significant" and "insignificant- spiUs. ' ^^^'''^i^S^terials and wastes should be stored in covered containers and protected from vandalism. Place a stockpile of spUl cleanup materials where it will be readily accessibte. Train employees in spiU prevention and cleanup. Designate responsible individuals. ICkaouQ Clean up leaks and spl\s unmediately. On paved surfaces, clean up spiUs wiU. as htUe water as possible. Use a rag for smaU spiU^ a damp mop for gcoeral cleanup, and absorbent matenal for larger spdk. If the spiUed material is hazardous, Uien Uie used cleanup materials are also ^dous and musl bc sent to ciUier a certified laundry (rags) or disposed of as hazardous waste. Never hose down or bury dry material spUls. Clean up as much onhe material as possible and dispose of properly. See Uie waste managemenl BMPs m Uus chapter for specific infonnation. ' ^""^ significant spUls to local agencies, such as Uie Fire Department; they can assist in cleanup. Fed.^ regulations require Uiat any significant oil spUl mto a -^^f^^yj^r^i" adjoming shorelme be reported to Uie National Response Center (NRC) at 80(M24- 8802 (24 hour). Targeted Pollutants O Sediment O Nutrients © Toxic Materials Q Oil A Grease O Floatable Iktaterials O Other Cor\stmction Waste # Ukely lo Hava SIfyilficant Impaci Q) Probable Low or Unkrutwn Impact Implementation Requirements O .Capital Coats Q OAMCoata O Maintenance Training O Suitability for Slopes >S% CA12 Best' Managemenl Practices^ Construction Handbook 4 - 13 March, 1993 ACTIVITY: SPILL PREVENTION AND CONTROL (continue) Use Uie foUowing measures related to specific activities: Always USC secondary containment, sucn as a urdiii ^ y changing fiuids. K„„. under oaving equipmeni when not in use. . w,s.„ ,.c,*s e™.. Don-, leave « drip pans o. o.^, containers lying around. ^„„,ncu,rs can leak oil and pollute slonn water. Place Uie oil filter in a funnel . Oil filters disposed of m ^^^^^^^o^f^c disposToil fUters can also be recycled. Ask your oU over a wasie oU recyclmg drum to drain excess uu IA, t^ suppUer or recycler about '^^'^^'^^l^'^;^^ ,„„^er. Do Uiis wiUi aU cracked baueries. even if you Uiink aU . Store cracked baUenes m ^^^'^ '^''^.^^^'^^^^ U is cracked. Put it into Uie containment area until you Uic acid bas drained out. If you drop a battery, ucai ii as are sure il is not leaking. ^^^^^^^5^^ use designated areas, located away from drainage courses, to preven. Uie mnon of stonn water and Uic mnoff of spUls. REQUIREMENTS Cosu (Capiul. O&M) - Prevention of leaks and spUls is inexpensive, quite expensive. • KT-P.. ..ppl^s 0, spU, conuol and c,can«p »,.na. on-*, „eac ..on,,e. nn,oad,ng. ^ nunn.enance . UpS,;. yoo, spm p«v„aon and conUoI pl». and sicck cleanup .n^lcrtals as changes occu, in *e „pes of chemicals on-site. t. Treaunenl and/or disposal of contaminated soil or water can be LIMITATIONS If necessary, use a private spiU cleanup company. REFERENCES ..-on Related Industries" Best Management Practices for Stonn Water PoUution Sr/an^a^"^^""!^^ Pollution Control Program, 1992. . ^ . ...^Ariivities. Developing PoUution Prevention Plans and Best Management Stonn Water Managemenl for Consuucuon Acuviues, ueveiopmg r u 1 Practices, EPA 832-R-92005; USEPA, April 1992. CA12 1 Consfruction Handbook 4 - 14 March, 1993 ACTIVITY: SOLID WASTE MANAGEMENT Giaphic; North Central Texas COG. 1993 Objectives Housekeeping Practices (^Contain Wasted Minimize Disturbed Areas Stabilize Disturbed Areas Protect Slopes/Channels Control Site Perimeter Control Internal Erosion ^'^e';'^^^^ Uic discharge of poUutants to stonn waier from solid or construction w^te by providing designated waste colleaion areas and containers, anangmg for regular disposal, and uaining employees and subcomractors. i So'lfdl^a^te " one of Uie major pollutants resulting from constmction. Consuucuon debris '""'"sohd waste generated from uees and shmbs removed during land clearing, demolition of existing suiictures (mbble), and building consimcuon; Packaging materials including wood, paper and plastic; Scrap or surplus buUding materials including scrap metals, mbber. plasuc. glass pieces, and masonry products; and Domestic wastes includmg food containers such as beverage cans, coffee cups, paper bags, and plastic wrappers, and cigareues. : Tbe following steps will help keep a clean site and reduce stonn water poUution: Select deygnated waste coUection areas on-site. Infonn Uash hauUng amtractors Uiai you will accept only water-tight dumpsters for on-site use. hispect dumpsters for leaks and repair any dumpster Uial is not water tight Locate containers in a covered area and/or in a secondanr containment Provide an adequate number of containers wiUi lids or covers Uiat can be placed over Uie conuincr to keep rain out or to prevent loss of wastes when u s windy. Plan for additional containers and more frequent pickup during Uie demoliuon phase of consuuction. CoUect site trash daily, especially during rainy and windy conditions. Erosion and sedmicnt control devices tend to coUecl Utter. Remove Uiis sohd waste prompUy. . Make sure Uial toxic hquid wastes (used oUs, solvents, and paints) ^bcmi^s (ackls, pesticides, additives, curing compounds) arc not disposed of m dumpsters designaied for construction debris. Salvage or recycle any useful material. For example, trees and shmbs from land clearing can be used as a bmsh banier (see ESC53), or converted imo wood chips. Uien used as mulch on graded areas (see ESCl 1). Do not hose out dumpsters on Uie consmiction site. Uave dumpster cleanmg to trash haulmg conlraclor. Anange for regular waste coUection before containers overflow. Targeted PoHutants O Sediment O Nutrients O TOXIC Materials O Oil A Grease # Floatable Materials 9 Other Construction Waste 1 * Ukely lo Have SignWcant Impact o Probable Low or o Unknown Impact 1 Implementation Requirements o Capital Costs o OAM Costs Q Maintenance Q Training O Suitability lor Slopes >5% High O Low CA20 Best Management Practices^ Construction Handbook 4 - IS March, 1993 ACTIVITY: SOLID WASTE MANAGEMENT (Continue) If ^roniainerdocsspiU, cleanup umiiediaiely. MakeCc Lt consuuction waste ,s collected, removed, and disfxised of only at auUiorized disposal areas. Tn^in emoloyecs and subconuactors in proper solid waste management ,c ^ . I7a ^irreTerencc on disposal alternatives for specif, wastes, see Tabte 4.2, CA40. Employee/Subcontractor Training. REQUIREMENTS Costs (Capital, O&M) All of the above arc low cost measures. Maintenance CoUect site uash daily. - Inspect consmiction waste area regularly. - Anange for regular waste coUection. LIM FT ATIONS . Tbere arc no major Umitations to Uiis best managemempracuce. S™nt Praoices and Erosion Conlrol Manual for Consuuction Sites; Flood Control Distria of Maricopa Couniy, AZ, September 1992. Processes. Proa=dures, and MeUiods to Conuol Pollution Resulting from aU Constmction Activity; USEPA, 430/9-73- 007. 1973. Stonn Water Management for Constmction Activities. Develc^mg Pollution Prevention Plans and Besl Managemem Practices. EPA 832-R-92005; USEPA. April 1992. CA20 Consfruction Handbook 4 - 16 March, 1993 ACTIVITY: HAZARDOUS WASTE MANAGEMENT Giaphic: North Cenlral Texas COG. 1993 Objectives Housekeeping Practices (^Contain Waste^ Minimize Disturbed Areas Stabilize Disturbed Areas Protect Slopes/Channels Control Site Perimeter Control Internal Erosion ^IZ^'cZl Uie discharge of poUuunis to stonn water from hazardous waste Uirougb 1 r material use. waste disposal, and training of emptoyees and subcontractors. ' MlyT^^'eLmicals used on-site can be hazardous matenals which become hazardous waste upon disposal. Tbesc wastes may include: Paints and solvents; Pcuoleum products such as oils, fuels, and grease; Herbicides and pesticides; Acids for cleanmg masonry; and Concrete curing compounds. m addition, sites wiUi existing suucoires may contain wastes which must be disposed of in accordance wiUi Federal. State, and tocal regulations. Tbesc wastes include: ' Sandblasting grit mixed wiUi lead-, cadmium-, or chromium-based pamts; Asbestos; and PCBs (particularly in older transformers). I The foUowing steps will bclp reduce stonn waier pollution from hazardous wastes: Material Use . Use aU of Uie produa before disposmg of Uie container. . Do not remove Uic original produa latx.1. it contains important safety and disposal information. . Do not over-apply herbicides and pestiddes. Prepare only UH: amounl needed. Foltow Uic recommended usage-msuuaions. Over-appUcation is expensive and cnvuonmentally hannful. Apply surface dressings in several sma^er appl^ns as opposed to one large appUcation. to aUow ume for infiltration and to ^vo.d exc^ Iterial being canied off-site by runoff. Do not apply ^^^''^'^'l^^'^Z rains. Peopte applymg pesticides must IK certified m accordance wiUi Federal and State regubtions. DO not clean oul boisbes or rinse pain, containers into Uie dirt, sUeet, drain orsueam. "Paint out" bmshes as much as possible. Rinse water-based pamts ,o Uie sanitary sewer. Filter and rc-use Uimners and solvents. Dispose of excess oil- based paints and sludge as hazardous waste. Targeted Pollutants O Sediment O Nutrients O Toxic Maierials O Oil A Grease O Floatable Materials O Other Conslrucl/on Waste # Ukely to Hav Slgnincanl Impact O Probable Low or Unknown Impact Implementation Requirements O Capital Costs O OAM Costs Q Maintenance ^ Training O Suitability for Slopes >S% High O Low CA21 Best' Management Practices^ Consfruction Handtiook 4 - 17 March, 1993 ACTIVITY: HAZARDOUS WASTE MANAGEMENT (Continue) ~^SSS.aousw.s,ec«„ecOona,easo„.sl«. . ^^Is n^erials and was.es sbou.d be s,0,«, in cov„ed contained and pieced fo. vandal.sn,. : —:=ra::r:r^^^^^^^ "c^^"LTa,. no, disposed or in don.ps,e,s designa^d lo, cons,n,cuon debns. | . ;rat^^"r:fsposa.ai»™ab.es.o,s^c.r«was,es.seeTab.4.^CAdO.Bn,p,oyce/So^^^^^^ Training. ?^ employees and subconiraaors in proper hazardous was.e managemen.. . Waming signs should be placed in areas rec^nUy ueated wiUi chemicals. . Place a stockpile of spill cleanup matenals where i. will be readily accessible. . If a container does spill, clean up immediately. REQUDIEMENTS . Costs (Capital. O&M) All of Uic above are low cost measures. Maintenance - Inspect hazardous waste receptacles and area regularly. - Arrange for regular hazardous waste collection. "-Ta^rLte Uiat cannot be reused orrecycledmust be disposed ofbyali^^^ ^o!S;fro^CteanBay.Constmction-Relatedlndus^es:Best„^^^ Prevention; Santa Oara Valtey Nonpoint Source PoUuuon Control Program, 1992. Processes. Procedures, and MeUiods to Conuol Pollution Resulting from aU Constmction Aoivitr. USEPA, 430/9-73- 007, 1973. Stomiwater ManagementforConsuuction Activities, Developing Pollution Prevention Plans and ^^^^ Practi«s, EPA 832-R-92005; USEPA, April 1992. CA21 Consfruction Handbook 4 - 18 March, 1993 ACTIVITY: CONTAMINATED SOIL MANAGEMENT ,..S3f.f4.>^..-jij?>i;- nFSCRIPTION ftevent or reduce Uie discharge of poUutants to stonn wa.er from contaminated soil and ' Sracklic or alkaline soils by conducting prc-consuucuon surveys, mspecung cxcava- I tions regulariy. and remediating conlaminaied sod prompUy. APPROACH I Contaminated soils may occur on your site for several reasons including: Past site uses and activities; Detected or undetected spills and teaks; and Acid or aUcaline solutions from ex[X>sed soil or rock foraiauons high m acid or aUcaline-forming elements. I Most developers condua pre-<onsUuction envuonmental assessments ^^^'^'f Zu.c. Rcc^ui coun mlings holdmg ,mmM^ "abte for cteanup costs when Oiey iiowingly move contaminated soil, highlight Uic need for conuaclors to confum dial a site assessmenl is compteted bcforc earth moving begins. Tbe foUowing steps will help reduce stonn water pollution from contammated soil: Conduct Uiorough site planning including pre-consuuction geologic suiveys. Look for contaminated soil as evidenced by discoloration, odors, differences m sod properties, abandoned underground tanks or pipes, or buned debns. Prevent leaks and spilb to Uie maximum extent practicable. Contammated soil can be expensive to treal and/or dispose of properly. However, addressmg Uie problem bcforc consuuction is much less expensive Uian afler Uie smKttires are in place. Test suspected soils at a certified laboratory. If Uie SOU is contaminated, woric wiUi Uie tocal regulatory agencies to develop opuons for treaunenl and/or disposal. For a quick reference on disposal alternatives for specific wastes, see Table 4.2, CA40. Employec/Subconuacior Training. I REQUIREMENTS Costs (Capital, O&M) - Prevention of leaks and spUU is inexpensive. TreaUnent and/or disposal of contaminated soil can be quite expensive. Maintenance - Inspect excavated areas daily for signs of ointaminated sod hnplement CA12. SpiU Prevention and Conuol. to prevent teaks and spiUs as much as possibte. Objectives Housekeeping Practices C^^C^lainWas^ j (^^inimize Disturbed Areas, Stabilize DisturbedAr^^ Protect Slopes/Channels Control Site Perimeter Control Internal Erosion Targeted Pollutants O Sediment O Nutrients # Toxic Materials O Oi7 * Grease O Floatable Materials O Olher Construct/on Waste # Ukely to Have SlgnWcant Impact O Probable Low or Unknown Impact Implementation Requirements O Capital Costs Q OAM Costs O Maintenance O Training O Suitability for Slopes >S% High O Low CA22 Best^ Management Practices^ Construction Handbook 4 - 19 March, 1993 Construction Handbook 4 - 20 March, 1993 ACTIVITY: CONCRETE WASTE MANAGEMENT i I ^^e^nf^e!ju«Uie discharge of pollutants to Stonn water ^^^^ SJi^g washout off-site, perfonning on-site washout in a designated area, and trainmg emptoyees and subcontractors. APPROACH 1 The foUowing steps will bclp reduce stora. water pollution from concrele wastes: Siore dry and wet materials under cover, away from drainage areas. Avoid mixing excess amounts of fresh concrete or cement on-site. Perfonn washout of concrete toicks off site or m designated areas only. . Do not wash out concrete uucks into stom drains, open ditches, slreels. or sueams. . Do not allow cx«ss concrete to be dumped on-site, except in designated areas. For on-site washout locate washout area at teast 50 feel from Stonn drains, open ditebes, or water bodies. Do not altow ninoff from Uiis area by consmicting a temporary pit or bermed area large enough for liquid and solid waste; - wash out wastes into Uic temporary pit where Uic concrete can set be broken up. and Uien disposed of properly- . When washing concrete to remove fme particles and expose thc aggregate, avoid creating ninoff by draining Uie water to a beraied or level area. . Do not wash sweepings from exposed aggregate conaete into die street or stonn drain. CoUect and return sweepings to aggregate base stock pite, or dispose in Uie trash. . Train employees and subconuaaors in proper concrete waste management. . For a quick reference on disposal alternatives for specific wastes, sec Table 4.2. CA40. Employee/Subconuacior Training. REQUIREMENTS . Costs (Capilal, O&M) All of the above arc low cost measures. • Maintenance - Inspect subamtiaaots to ensure Uiat concrete wastes arc bemg properly man- aged- , , . - If using a temporary piu dispose hardened oinaete oo a regular basis. LIMITATIONS . Off-site washout of conaete wastes may nol always be possibte. Objectives Housekeeping Practices C^Confa/n Wasted Minimize Disturbed Areas Stabifize Disturbed Areas Protect Slopes/Channels Control Site Perimeter Control Internal Erosion Targeted PoUutants O Sediment O Nutrients O TOXIC Materials O 0/7 A Grease O Floatable Materials O Other Construct/on Waste # Ukoly lo Have Significant Impact O Probable Low or Unknown Impact Implementation Requirements O CapHal Costs O OAM Costs Q Maintenance ^ Training O Suitability for Slopes >5% High O Low CA23 Best Management Practices'^ Consfruction Handbook 4 - 21 March, 1993 Consfruction Handtiook 4 - 22 March, 1993 ACTIVITY: SANITARY/SEPTIC WASTE MANAGEMENT Objectives Housekeeping Practices rnF^CRIPTI ON ' Prevent or reduce Uic discharge of pollutants to stonn water from sanitary/septic waste by providmg convcntenu weU-mainiaincd faciUties, and anangmg for regular service and I disposal. I S^^ or^septic wastes should be ueated or disposed of in accordance wiUi State and local requiremenis. These requiremenis may include: Locate sanitary facilities in a convenient location. Untreated raw wastewater should never bc discharged or buried. Temporary septic systems should ueat wastes to appropriate levels before dischargmg. If using an on-site disposal system (OSDS). such as a septic system, aimply wiUi local bcalUi agency rcquucments. Temporary sanitary facilities Uiat discharge to Uie sanitary sewer system should be properly connected to avoid ilUcit discharges. If discharging to die sanitary sewer, contact Uic local wastewater ueauneni planl for their rcquucments. Sanitary/septic facilities should be maintained in good working order by a licensed service. Anange for regular waste coitection by a licensed hauter before facUities overflow. For a quick reference on disposal altematives for specific wastes, sec Table 4.2. CA40. Employee/Subconuacior Training. REQUIREMENTS Costs (Capital. O&M) All of Uie above are low cost measures. Mainienancc Inspecl facUities regularly. Arrange for regular wasle coUection. LIMITATIONS . There arc no major limitations to Uiis best management pracuo;. REFERENCES ^ . j:,^ Best Management Practices and Erosion Control Manual for Consimcuon Sites; Flood Control Distria of Maricopa Couniy. AZ, September 1992. Siomi Water Management for Consuuction Activities. DevelV.ng PoUuu^ Plans and Best Managemenl Practices. EPA 832-R-92005; USEPA. Apnl 1992. C^^Contain Waste^ Minimize Disturbed Areas Stabilize Disturbed Areas Protect Slopes/Channels Control Site Perimeter Control Intemal Erosion Targeted Pollutants O Sediment O Nutrients O Toxic Materials O 0/7 A Grease O Floatable Materials O Other Construct/on Waste 1 • Ukely lo Have Slgnincanl Impaci o Probable Low or o Unknown Impact Implementation Requirements o Capital Costs o OAM Costs o Maintenance o Training o Suitability for Slopes >5% High O Low CA24 Best' Management Practices'* Construction Handbook 4 - 23 ACTIVITY: VEHICLE AND EQUIPMENT CLEANING Objectives Graphic: Morth Central Texas COG. 1993 REFERENCE Contain Wasle Minimize Disturbed Areas Stabilire Disturbed Areas Prolecl SlopesJChannels ft!!cnt or reduce Uie discharge of pollutants to stonn water from vehide and eqtupmem Sg^y usmg off-site faciUties. washing in designated, conumed areas only elmunat- int^Ses to Uie stonn drain by infUirating or recycUng Uie wash water, and/or training employees and subconuacte>rs. ^'^^'^^^ o^-site commercial washing businesses as much as possible. Washmg vcbictes and equipmen. ouUJoors or in areas wbere wash wa.er Hows on.o paved surfaces or intoSainagepaUiways can poUute Stonn water. If you wash a large number of vchiclS oTpiLs of equipment, consider conduOing Uiis woric at a3 off-site commer^ cS business, "mese businesses arc better cquipix^d to handte and dispose of Uie wash waters properly. Perfonning Uiis work offsite can also be economical by chminatmg Uic need for a separate washing operation at your sue. If wasb-mg musi oorur on-site, use designated, benned wash areas to prevent wash wateTcTntaci wiUi stonn water, creeks, rivers, and oUier waler bodies. Tbe wash area can be sloped for wash water coUection and subsequail infiltration mto Uic ground- Use as littie water as possible to avoid having to install erosion and sediment coouols for Uic wash area. Use phosphate- free, biodegradable soaps. Educate employees and subconiraaors on pollution prevention measures. Do not pennit steam cleaning on-site. Steam cleaning can genaate significant poUutant concentrations. - For a quick reference on disposal alternatives for specific wastes, sec Table 4 Jt. CA40, Employee/Subconuaaor Training. REQUDIEMENTS . Costs (CapiuL O&M) All of Uic alx>vc are low cosl measures. • Maintenance - Minimal, some berm repair may be necessary. I'"\'^e^n'S^'!Lte-free. biodegradable soaps have been shown to be toxic to fish before Uic soap degrades. -KTrcr-i^ . Sending vcbiclcs/cquipment off-site should bc done in conjunction wiUi ESC24 (StabiUzed Constiiictioa Entrance). Confro/ Intemal Ero^n^ Targeted PoUutants O Sediment O Nutrients O Toxic Materials ^ 0/7 A Grease O Floatable Materials O Other Coiistruction Waste t • Ukely lo Have 1 1 1 Slgnincanl Impact 11 o Probable Low or 1 1 o Unknown Impact j 1 Implementation Requirements Q Capital Costs O OAM Cost* O fUlaintenance O Training O Suitability for Slopes >SX High O Low CA30 Best' Management Practices"^ 4 - 24 March, 1993 ACTIVITY: VEHICLE AND EQUIPMENT FUELING Objectives Contain Waste Minimize Disturbed Areas StabiUze Disturbed Areas Protect Slopes/Channels Conlrol Site Perimeter Control Intemal Erosion S^ent fuel spills and leaks, and reduce Uiefr impacts to stonn water by usmg of -site ScUi^TucUng -m designated areas only, enclosmg or covering stored fuel, miplemenung spiU controb. and training emptoyees and subconuactors. ' orf-site fueling stations as much as possibte. FueUng vehicles and equipmeni ou^oors or in are^ where fuel may spill/leak onto paved surfaces or mto drainage pa^^ can poUute stonn water. If you fuel a large number of vehicles or pieces of equipment consider using an offsi.e fueUng station. Tb«e ^^^l^^^^^^^^'^ ^ equipped to handle fuel and spills properly. Perfonnmg Uus work off-site can also be economical by eluninating Uie need for a separate fuelmg area at your site. If fueling mus. occur on-site, use designated areas, located away from drainage courses, to prevent U>c mnon of storai water and Uie mnoff of spdls. Discourage "toppmg-off' of fuel tanks. Always use secondarr containment such as a drain pan or drop cloUi. when fuelmg to calch spills/leaks. Place a stockpile of spUl cleanup materials where il wUl be readily accessibte. . Use adsortient materials on small spdls raUier Uian hosmg down or burymg Uie spiU. Remove Uie adsorbent materials promptiy and dispose of properly. . Cany oul all Federal and State requhements regarding stationary above ground Storage tanks. . Avoid mobile fueling of mobile constmction equipment around Uie site; raUier uansport Uie equipment lo designated fueUng areas. WiUi Uic ""P'^^";^'^^f equipment such as buUdozcrs and perhaps forid if is. most vehicks should be able to uavel to a designated area wiOi lilUe lost time. . Train employees and suba>nuaclors in proper fueUng and cteanup procedures. - For a quick reference on disposal alternatives for specific wastes, see Tabte 4.2, CA4U, Employec/Subcontracior Training. REQUIREMENTS . Costs (Capital, O&M) - All of Uie above measures are tow cosu except for Uie capital oisis of above ground tanks Uiat meet aU local environmental, zomng. and fuc codes. Maintenance - Keep ample suppltes of spUl cleanup materials on-site. - Inspect fuelmg areas and storage tanks on a regular schedule. LIMFFATIONS .h P';r74 Sending vehicles/equipment off-site should be done in conjuncuon wiUi ESC24 (Stabilized Consu^iction Enuance). Targeted PoUutants O Sediment O Nutrients O Toxic Materials O Oil A Grease O Floatable Materials O Olher Constrvction Waste # Ukely to Have Slgnincanl Impact O Probable Low or Unknown Impact Implementation Requirements Q Capital Costs O OAM Cosfs O Maintenance Q Training O Suitability for Slopes >5% High O Low \\ CA31 Best^ Management Practices^ Construction Handbook March, 1993 ACTIVITY: VEHICLE AND EQUIPMENT MAINTENANCE Graphic: North CenUal Texas COG. 1993 [DESCRIPTION Prcvem or reduce Uie discharge of pollutants to storai water from vehicle and equipment maintenance by mnning a "dry site". This involves using off-site facU.ues. perfonning work in designated areas only, providing oivcr for materials stored outside, checking for leaks and spUls. containing and cleaning up spiUs munediately. and Uainmg employees and j I subcontractors. I APPROACH Keep vehicles and equipment clean, don't aUow excessive build up of oil and grease. Use offsite repair shops as much as possibte. Maintaining vehicles and equipment outdoors or in areas wbere vehicte or equipment fluids may spiU or leak onto Uie ground can pollute slorm water. If you mainuin a large number of vehicles or pieces of equipment consider using an offsite repair shop. Tbesc businesses are better equipped to handle vehicte fiuids and spiUs properly. Perfonnmg Uiis woric offsite can also be economical by eUminatijig the need for a separate maintenance area. If maintenance musl occur on-site, use designaied areas, locaied away from drainage coiirses, to prevent Uie mnon of storm waier and Uie mnoff of spdls. Always use secondary conlainment such as a drain pan or drop cloUi, lo calch spills or I leaks when removing or changmg fiuids. Place a suxkpile of spUJ cleanup materials where it wUl be readily accessible. Use adsortient materials on small spUls raUier Uian hosmg down or burymg Uie spUl. Remove thc adsorbent materials prompUy and dispose of properly. Regularly inspea on-site vehicles and equipment for leaks, and repair immediately. Check mcoming vehicles and equipment ("mcluding deUvery uucks, and employee and suboonttaaor vehicles) for leaking oil and fiuids. Do not aUow leaking vehicks or equipment on-site. Segregate and recycte wastes, such as greases, used oi! or oU filters, antifreeze, ckanmg solutions, automotive batteries, hydrauUc. and transmission fluids. Train employees and subconuaaors in proper maintenance and spiU ckanup proce- dures. Fbr a quick reference oa disposal altematives for specific wastes, sec Tabte 4.2, CA40, Employce/Subcontraclor Training. I REQUIREMENTS Costs (Capital, O&M) All of Uic above are low cost measures. Maintenance Keep ample supplies of spUl cleanup materials on-site. Inspect maintenance areas on a regular schedule. Objectives Housekeeping Practices^ Contain Waste Minimize Disturbed Areas Stabilize Disturbed Areas Protect Slopes/Channels Control Site Perimeter Control Intemal Erosion Targeted Pollutants O Sedinyent O Nutrients Toxic Materials Oil A Grease Q O Floatable Materials O Other Construction Wasle # Ukely lo Hav* Slgnincanl Impact O Probable Low or Unknown Impact Implementation Requirements O Capital Costs O OAMCo5ts O Maintenance 9 Training O Suitability for Slopes >5% High O Low CA32 Best Management PracticesN Construction Handbook 4 - 26 March, 1993 ACTIVITY: VEHICLE AND EQUIPMENT MAINTENANCE (Continue) ' 'Tn^'d^.g'leh.cles/equipment offsite should be done in conjuncuon wiUi ESC24 (Stabilized Consuucuon Enuance). I - . vo.^nnnrr is a DOtentiaUv Significant source of siotm water pollution. Activities that Outdoor vehicle or ^^"'P-^^^^^; service, particularly changing or replacement of fluids, and can contaminate storai "^^'^'^^^Xp^.rengines). For further infomiation on vehicte or equipment servicing. outdoor equipment storage and ^^^^"^^^26 CA31. Vehicte and Equipmeni Fueling. seeC/^0. Vehicle and Equipment Cleaning, ana <-/^->I. ^ f Listed betow is further inforaiation if you musl perioral vehicle or equipment maintenance on-site. F^^^*^^*^^*^ A • „,„.n.. such as uicbtoroeUiylene.l.l.l-uichloroeUiane. or mcUiylenc chloride. Many of Parts are often cteaned "^'^S ^^''.^^^^d of L a hazardous waste. Reducing die number of solvents makes ibesc pans ^'-^^ ^ ^^^.'^w^^^^ costs. Often, one solvent am perfomi a job as wel. as two recyclmg caster ^^^'^"^^^^f" ^^^3^, J,ce Uic amount of hazardous materials and waste by subsuiuung different solvents. Also, if ^'^^^ZTF^Z^PXC. replace chlorinated organic solvents (l.l.I-uichtoroeUiane. non-hazardous or tess '^^'^^^^^^f^^^^^^^^ Non-chlorinated solvents Uke kerosene or mmeral spuits are meUiytene cblonde. ete.) J-^^^^^-^^V^^^^^^ check Ust of aoive ingredients to sec wbeUier it ointains chlori- I to clean parts. ^'^'''^^^'''^'^TfJ^ for caster recyclmg and may reduce disposal costs. Keep hazardous and non-hazardous wastes Separaung "^I'^ ^J^ keep chtorinated solvents (like 1.1.1-UichloroeUiane) separate from non- dmms Don-1 leave full drip pans or oUier open containers lymg around. suppUer or recycler about recycUng oU filters. Do not dispose of exua paints and coatings by dumping Uquid onto die ground or Uirowing it into dumpsters. Altow coatings IO dry or harden before disposal into covered dumpsters. V A H.„.ri.. ;„ a non leafcine secondary container. Do Uiis wiUi aU cracked batteries, even if you Uimk aU Uic STbrdlneTo^lr^iXp^a^. uetulas if i. is aacked. Pn, i, in. O-e co„,ai„.e», »ea nnU yon a. sn,e « is not leaking. Do not bury used tires. REFERENCES Best Management Practices and County. AZ, September 1992. Erosion Conuol Manual for Consuuction Sites; Hood Conuol Distria of Maricopa Blueprint for a Ctean Bay-Consuuction Related Industries: Best Management Practices for Stonn Water PoUution Prevention; SanU Clara VaUey Nonpoint Source PoUution Conuol Program. 1992. Coastal Nonpomt Pollution Conuol Program: Program Development and Approval Guidana., Woricing Group Working Paper. USEPA. April 1992. Construciion Handliook 4 - 27 March, 1993 ACTIVITY: EMPLOYEE/SUBCONTRACTOR TRAINING Objectives Minimize Disturbed Areas Stabilize Disturbed Areas Protect Slopes/Channels Control Site Perineter Control Intemal Erosion DEISCRIPTION 1 Emptoyee/subconuaaor uaining. like maintenance or a piece of equipment is not so much a best managemen, pracucc as ! it is a mcibod by which to unplement BMPs. This fact sheet highlights Uic rniportano: of uainmg and of integraung Uic etements of anploycc/subconuactor uainmg from Uie individual source oinuols into a comprehensive uainmg program as part of a company's Storai Water Pollution Prevention Plan (SWPPP). Tbe spedfic employee/subconuaaor uaining aspects of each of Uic source conuols are highlighted in Uie mdividual fact sheets Tbe focus of Uiis fact sbeet is more general, and includes Uie overall objectives and approach for ^ssunng cmptoyee/subconuacior uaming m storai water poUution prevention. Accordmgly. Uie organuation of Uus fact sheet differs somewhat from Uie other facl sheets in Uiis chapter. OBJECTFVES Employee/subconuaaor training should be based on four objccuves: . ^ , ^n„„ • Promote a clear identification and undastandihg of Uic problem, including acuviues wiUi Uic potenual to pollute storm water. Identify solutions (BMPs); Promote employce/subconuactor ownership of Uie probtems and Uie solutions; and Integrate cmployee/subconuactor feedback into uaining and BMP implementation. "^^^IntegrSftrainmg regarding storai water quality management w.Ui existing uainmg programs ^bal may be requued for your busmess by other regulations such as: Uie lUness and Injury Prevention Program OIPP) (SB 198) (California Code of Regulations Tide 8. Section 3203). Uie Hazardous Waste Operafions and Emergency ^^V^ (HAZWOPER) siandard (29 CFR 1910.120). Uic SpUl Prevention Conuol and Countermeasure (SFt_t-) CFR 112). and Uic Hazardous Materials Management Plan (Business Plan) (California HcalUi and Safety Code, Section 6.95). Busmesses. particularly smalkr ones Uiat may not bc regulated by Federal. State, or local regulauons, may use Uic infonnation in Uiis Handbook to develop a uaining program to reduce Uieir potential to pollute storai water. Use Uic quick reference on disposal altematives (Fable 4.2) to uain employcc/subcoouaciors m proper and consistent methods for disposal. CA40 Best^ Man: Practices"* lagemenl Consfruction Handbook 4 - 28 March, 1993 ACTIVITY: EMPLOYEE/SUBCONTRACTOR TRAINING (continue) ^^^^^^^^^^^^^^^^^^^ untoading and handUng of materials. r,,;fomia Deoartment of Pesticide Regulation and inspections. ,,^V^A Thf rnnvientious efforts of weU uained employee/ xrrantr.==rr»^^^^^^^^ arc expecied to do on-silc. CA40 Consfruction Handbook 4-29 TABLE 4.2 QUICK REFEF :E - DISPOSAL ALTERNATIVES (Adopted from Santa Clara County Nonpoint source Pollulion Control Program - December 1992) All of the waste products on Uiis chart are prohibited from discharge to the siorm drain system. Use this matrix to decide which aJtemalive disposal strategies to use. ALTERNATIVES ARE LISTED IN PRIORITY ORDER. © 3 33 3 O. er § Key: HHW Household hazardous waste (Government-sponsored drop-off events) POTW Publically Owned Treatment Plant Reg.Bd. Regional Water Quality Control Board (Oakiand) "Dispose to sanitary sewer" means dispose into sink, toilet, or sanitary sewer clean-out connecLion. _ "Dispose as trash" means dispose in dumpsters or trash containers for pickup and/or eventual disposal in lancinu, "Dispose as hazardous waste" for business/commercial means comract with a hazardous waste hauler to remove and dispose. DiSCHARGEyACTIVITV BUSINESS/COMMERCIAL Disposal Priorities Approval RESIDENTIAL Disposal Priorities General Construction and Paintinp; Street s Excess paint (oil-based) nd Utility Maintenance 1. Recycle/reuse. 2. Dispo.se as hazardous w.Tsie, 1. Recycle/reuse, 2, Take lo HHW drop-off Excess paint (water-based) 1. Recycle/reuse. 2. Dry residue in cans, dispose as uash, 3. If volume is loo much lo dry, di.<;r>ose as hazardous wnsie, 1, Recycle/reuse. 2, Dry residue in cans, dispose as u-asli. 3, If volume is ioo much lo dry, uikc lo HHW drop-off Paint cleanup (oil-based) Wipe paint oul of brushes, Uicn; 1. Filler & reuse thinners, solvents, 2. Dispose as hazardous waste. Wipe pajiu oul of brushes, ilicii: 1, Filler & reuse Uiinners, sol veins. 2. Take lo HHW drop-off. Paint cleanup (water-based) Wipe paint out of brushes, tlien: 1, Rinse to s.inilary sewer. Wipe paint out of brushes, tJieii: 1, Rinse to smiiiary sewer. Pmntv n.iint cans (drv) 1. Remove lids, dispose as uash. 1, Remove lids, dispose as tra.'ih. Paint strionine (wilh solvent) 1. Distxjsc as hazardous wasic. 1, Take to HHW drop-off. Building exterior cleaning (high- pressure water) 1. Prevent enO-y into slorm drain and remove offsite 2. Wash onto dm area, spade in 3. Collect (c.g.'mop up) and discharge to sanitary sewer POTW Cleaning of building exteriors which have HAZARDOUS MATERIALS (e.g. mercury, lead) in paints 1. Use dry cleaning methods 2. Conuin and dispose washwater as hazardous waste (Suggestion: dry material first lo reduce volume) 1>J o Ul Table 4.1 (Continued) Page 2 DISCHARGE/ACTIVITY 3 I X II General Construction and Painting; Street Non-hazardous paint scraping/ sand blastint HAZARDOUS paint scraping/sand blasting (e.g. marine painis or points containing lend or unbutyl ti") Soil from excavations during periods when storms are forecast BUSINESS/COMMERCIAL Disposal Priorities Approval and Utility Maintenance (cont'd) 1. Dry sweep, dispose as trash 1. Dry sweep, dispose as hazardous waste 1, Should not bc placed in su-ect or on paved areas 2, Remove from site or backfill by end of day 3. Cover widt tarpaulin or surround with hay bales, or use oOier runoff conuols 4. Place filler mat over stonn drain Note: Thoroughly sweep following removal of dirt in all four .nliematives. RESIDENTIAL Disposal Priorities Soil from excavations placed on paved surfaces during periods when stonns are not forecast Cteaning streets in consuTJCtion areas Soil erosion, sediments Fresh cement, grout, mortar Washwater from concreie/morxar (etc.) cleanup Aggregate wash from driveway/pauo consiruction 1. Keep material oul of sionn conveyance systems .-uid Uioroughly remove vi;> sweeping following i-einov.-d of dirl 1, Dry sweep and minimize u-.ncking of mud 2. Use silt ponds and/or similar pollutam reduction techniques when flushing lavement 1, Cover disturbed soils, use erosion controls, block cnU7 lo sionn drain, 2. Seed or plant immediately. 1. Use/reuse excess 2. Dispose to tfash 1, Wash onto dirt area, spade in 2, Pump and remove to appropriate disposal facility 3, Settle, pump water to saniuvy sewer 1, Wash onto din area, spade in 2, Pump and remove lo appropriate disposal facility POTW rv-vTMr I, Dry sweep, dispose as u^sh 1, Dry sweep, take to HHW drop-off 1, Use/reuse excess 2. Dispose as UTtsh 1, Wash onto dirt area, spade in 2, Pump and remove lo appropriate disposal facility 3, Seiile. pump water to snniUTry sewer 1, Wash onto dirt area, sp.nde in 2, Pump and remove to appropriate disposal facilily 1 C.iiU r,i,mn \imii>r lr\ <:anilnrv cp.wrr Table 4,1 (Co. .i) Table 4,1 (Continued) Page 4 n o o 3 X ti 3 CJ 5» Dumpster cleaning water Cleaning driveways, paved areas * (Special Focus « Resuiurant alleys Grocery dumpster areas) • Note: Local drought ordinances may contain additional resfrictions Steam cleaning of sidewalks, plazas • • Note: Local droughl ordinances may contain additional restficiions Potable waier/line Hushing Hydrant testing Supcr-chlorinatcd (above 1 ppm) waier from line flushing I. Insure lhat bins are used for dry nonhazardous materials only (Suggestion: Fencing, covering help prevent misuse) 1, Clean at dumpsier owner's facilily and discharge waste dirough grease interceptor to sanitary sewer 2, Clean on sile .and discharge liirougli grtase inierceptor lo saiiii.ary sewer 1, Sweep and dispose as irash (Dry cleaning only), 2, For vehicle leaks, rcstauranl/groccry alleys, follow Uiis 3-sicp process: a. Clean up leaks wilh rags or absorbcitis. b. Sweep, using granular absorbciu material (cal liuer). c. Mop and dispose of mopwaicr lo s;mitary sewer (or colleci rinsewnicr and pump to Uie sanitary sewer), 3, Same as 2 above, bul with rinsewater (2c)(no soap) discharced to storm drniii. 1, Colleci all waier and pump to sanitary scwcr* 2. Follow Uiis 3-step process: a. Clean oil leaks wiUi rags or adsorbents b. Sweep (Use dry absorbent as needed) c. Use no soap, discharge lo storm drain I, Deactivate chlorine by maximizing ume water will travel before reaching creeks 1, Discharge to saniuuy sewer 2, Complele dechlorination required before discharge to slorm drain POTW POTW , Sweep and dispose as u-.ish (Dry cleaning only). 2. For vehicle leaks, follow Uiis 3-siep process; a, Cleiui up leaks wiUi rags or absorbents; dispose as hazardous waste. b, Sweep, using granul.v absorbent material (cal lilicr), c, Mop and dispose of mopwntcr to sani(iu-y sewer, Tabic 4,1 (Co; * 5 o 3 X 3 a. 2 DISCHARGE/ACTIVITY BUSINESS/COMMERCIAL Disposal Priorities Approval RESIDENTIAL Disposal Priorities Landscape/Garden Maintenance Pesticides Garden clippings Tree uimining Swimming pool, spa, founutin water (emptying) Acid or oUier pool/spn/founiain cleaning Swimming pool, spa filter backwash 1. Use up, Rinse containers use rinsewater as product. Dispose rinsed conuiners .is irash 2, Dispose unused pesticide as hazardous wasje 1, Compost 2. Take to Landfill 1, Chip if necess.vy, before composting or recycling 1. Do noi use metal-based algicides (i.c, Copper Sulfate) 2. Recycle/reuse (e.g. imgaiion) 3. Detennine chlorine residual » 0, wan 24 hours and Uien disch.-u-ge to stonn dr;un. 1, Ncuu-alize and discharge to saniuvy sewer 1. Reuse for irrigation 2. Dispose on dm area 3. Settle, dispose lo sanitary sewer I, Use up. Rinse containers, use rinsewater as pesticide. Dispose rinsed coniaincr .is irash. 2 Take unused pesucidc to HHW drop- off 1, Compost 2, Dispose as trash. 1, Chip if nccess;uy. bcforc composting or recycling 1, Do not use metal-based algicides (i.e. Copper Sulfate) , 2, Recycle/reuse (c.g. imgaiion) 3 Detennine chlorine residual = 0, wait 24 hours .md llien disch.-u-gc to slunn dniin. 1, Use for landscape irrigauon 2, Dispose on din .Trea 3, SelUe, dispose to s<^ulil•^ry sewer Vehicle Wastes Used motor oil Antifreeze OOier vehicle fluids and solvents Automobile batteries I, Use secondary conlainment while ' storing, send to recycler. 1. Use secondary containment while storing, send to recycler. I. Dispose as hazardous waste 1. Send to auto battery recycler 2. Take to Recycling Center Motor hoine/construaion frailer wasle 1. Use holding tank. Dispose to leiniuu-v sewer _ 1, Put oul for curbside recycling pickup where available 2, Take to Recycling Facility or auto service facility wiUt recycling program 3, Take lo HHW evenls accepting moior on 1, Take to Recycling Facility 1, Take to HHW event 1, Exchange at reuiil ouUei 2. Take to Recycling Faaliiy or HHW cvcni where baileries are accepted 1. Use holding lank, dispose lo s.anit-'u-y sewer. _ Table 4.1 (Coniinued) Page 6 © 5 © 3 X u 3 O. $ o 2 n sr vo vO Ul Vehicle Wastes (cont'd) Vehicle Washing Mobile Vehicle Washing Rinsewater from dust removal at new car fieeis Vehicle leaks al Vehicle Repair Facilities 1, Recycle 2. Disch.-u-ge to sanitary sewer, never to slonn drain 1, Collect washwater and discharge lo saniiitfy sewer. 1. Disch.vge to saniuuy sewer 2. If rinsing dust from exterior surfaces from appearance purposes, use no soap (water only): disch.irge to sionn drain. Follow this 3-siep process: 1, Clean up leaks wiUi rags or absorbents 2, Sweep, using granular absorbent malerial (cal litier) 3, Mop and dispose of mopwater to saniuiry sewer, POTW POTW POTW 1. Tttke to Commercial Car Wash, 2. Wash over lawn or din area 3. If soap is used, use a bucket for soapy water and discharge rem.nining soapy water to siuiiuuy sewer. Carpel cleaning solutions & other mobile washing services Roof drains Cooling water Air conditioning Pumped groundwater, infilu^tion/ foundation drainage (contaminated) Fire fighting flows 1, Dispose to saniuu-y sewer 1. If roof is conuuninalcd wiOi industrial waste products, discharge to sanitary sewer 2. If no contamination is preseni, discharge to storm drain 1. Recycle/reuse" 2, Discharge to sanit 1. Recycle/reuse (landscaping, etc,) 2. Treal if necessary; discharge to sanitary sewer . 3. Treat and discharge to storm drain If contamination is present, Fire Dept. will attempt to prevent flow to su-eam or storm drain POTW POTW Reg, Bd. POTW Reg. Bd, 1. Dispose to saniuu-y sewer 4.0 RF.ST MANAGEMENT PRACTICES FOR EROSION AJ<D SEDIMENT CO^jTROL^ 4.1.2-a Preservation of Existing Vegetation 4.0 BEST MANAGEMENT PRACTICES FOR EROSION AND SEDIMENT CONTROL 4.1.3-a Minimize Disturbance and Buffer Strips RUFFER STRIP_OF VEGETATION On construction sites, a 50 foot buffer (filter) strip of undisturbed vegetation should be left along all watercourses and property lines. This stnp reduces v/ater velocity and traps sediment, thereby reducing sediment delivery to surtace waters or lo adjacent properties. Special care should be taken during the construction process to see that soii is not washed into a body of water. Conventional snow-fencing should be erected alonq the limits of planned soil disturbance to prevent machiner/ and debns from entering the buffer strips or watercourses, and to limit the disturtiance of soil and vegetation to what is absolutely necessary. DIVERSION NATUflAt VEGETATIVE FILTER STRIP . EXPOSED CONSTRUCTION AREA TEMPORARY SEDIMENT TRAP EXISTING WATERWAY r NATURAL FILTER STRIPS Source: j Unknown OF VEGETATION 4-11 4.0 BEST MANAGEMENT PRACTICES FOR EROSION AND SEDIMENT CONTROL 4.1.5-a Land Grading for Minimizing Erosion 10V. SETTLEMENT O.r FREE BOARD TYPICAL PARABOLIC DIVERSION 10V. SETTLEMENT O.r FREE BOARD TYPICAL TRAPEZOIDAL DIVERSION 10*/. SETTLEMENT-^ O.r FREE BOARD- DESIGN FLOW OEPTM TYPICAL VEE-SHAPED DIVERSION DIVERSIONS Source: Va. DSWC BEST ^Ly^AGEMENT PRACTICES FOR SAN DffiGO COUNTY - 1998 4-15 4.0 BEST MANAGEMENT PRACTICES FOR EROSION AND SED PMENT CONTROL 4.1.5-b Land Grading for Minimizing Erosion — DIVERSION SECTION OF DIVERSION AT TOP OF SLOPE DIVERSION: INTERCEPTS STORM WATER RUNOFF NEWLY SEEDED AND MULCHED SLOPE PROTECTED BY DIVERSION STABLE OUTLET DIVERSION CONTROL MEASURES CAN INTERCEPT STORM WATER RUNOFF BEFORE IT REACHES SLOPES DIVERSION DIKE Source: Unknown BEST NL^NAGEMZNT PRACTICES FOR SAN DIEGO COUNTY - 1998 4-16 4.0 BEST MANAGEMENT PRACTICES FOR EROSION AND SEDIMENT CONTROL 4.3.1-a Geotextiles and Mats r ANCHOR SLOTS: BURY THE UP CHANNEL END OF THE NET IN A 12" DEEP TRENCH. TAMP THE SOIL FIRMLY STAPLE AT 12- INTERVALS ACROSS THE NET. FLOW OVERLAP: OVERLAP EDGES OF THE STRIPS AT LEAST tr. STAPLE EVERY 12" DOWN THE CENTER OFTHE STRIP JOINING STRIPS: INSERT THE NEW ROLL OR NET IN A TRENCH. AS WITH THE ANCHOR SLOT OVERLAP THE UP-CHANNEL END OF THE PREVIOUS ROLL 18" AND TURN THE END OF THE PREVIOUS ROLL, JUST BELOW THE ANCHOR SLOT, LEAVING 6" OVERLAP CHECK SLOTS: ON ERODIBLE SOILS OR STEEP SLOPES, CHECK SLOTS SHOULD BE MADE EVERY 15 FEET. INSERT A FOLD OF THE NET INTO A 6" TRENCH AND TRAP FIRMLY, STAPLE AT 12" INTERVALS ACROSS THE NET. LAY THE NET SMOOTHLY ON THE SURFACE OF THE SOIL - DO NOT STRETCH THE NET. AND DO NOT ALLOW WRINKLES. ANCHORING ENDS AT STRUCTURES: PLACE THE END OF THE NET IN A12" SLOT ON THE UP-CHANNEL SIOE OF THE STRUCTURE- FILL THE TRENCH AND TRAMP FIRMLY ROLL THE NET UP THE CHANNEL PUCE STAPLES AT ir INTERVALS ALONG THE ANCHOR END OF THE NET. INSTALLATION OF NETTING AND MATTING Source: California Storm Water BMP Handbook, Construction Activity, March 1993. BEST MANAGEMENT PRACTICES FOR SAN DIEGO COUNTY -1998 4-16 4.0 BEST MANAGEMENT PRACTICES FOR EROSION AND SEDIMENT CONTROL 4.3.1-b Geotextiles and Mats ON SHALLOWSLOPES. STRIPS OF NETTING MAY BE APPLIED ACROSS THE SLOPE. SECTION ON STEEP SLOPES. APPLY STRIPS OF NETTING PARALLEL TO THE DIRECTION OF FLOW AND ANCHOR SECURELY. SECTION I I > 1 1 . :• • • 1 ; 1 l-lll J 1 U-L H—:—! 1 . • = , : 1 1 I 1 > . . I • 1 1 • 1 ' 1 1 .1-1 . . 1 . t 1 1 ! 1 ! i 1 • 1 I 1 1 I llll 1 1 TT' 1 1 — ..111 • . . ill -m III —,-H 1 .1 -h 1 1 I • It. II'I , I . . - -\-\-:\ 1 1 1 1 1 1 111 1 1 1 1 1 1 1 1 (SHALLOWSLOPES) PLAN IN DITCHES. APPLY NETTING PARALLEL TO THE DIRECTION OF FLOW. USE CHECK SLOTS EVERY 15 FEET DO NOT JOIN STRIPS IN THE CENTcR I'-l I • ; • • I ' ' ' ' 11!!:!!!!!! \^ llMli i I } i 1. IIIII T-r OF THE DITCH. ± ANCHOR TRENCH (STEEP SLOPE) PLAN SECTION FLOW BRING NETTING DOWN TO A LEVEL BEFORE TERMINATING TWE INSTALLJVTION. TURN THE END UNDER S" AND STAPLE AT 1 r INTERVALS. BERM (DITCH) PLAN WHERE THERE IS A BERM AT THE TOP OF THE SLOPE, BRING THE MATTING OVER THE BERM ANO ANCHOR IT BEHIND THE BERM WITH A 12- ANCHOR TRENCH. ORIENTATION OF Source: California Storm Vtfater BMP 1 NETTING AND MATTING Handbook, Construction Activity, March 1993. J BEST MANAGEMENT PRACTICES FOR SAN DIEGO COUNTY - 1998 4-47 4.0 KVST MANAGEMENT PRACTICES FOR EROSION AND SEDIMENT CONTROL V. 4.3.3-a Temporary Stream Crossing AGGREGATE Fia FILTER CLOTH AGGREGAT E FllL -v p 12* MIN FOER CLOTH I I HIGH FLOW AREA HIGH FLOW AREA AGGREGATE FILL- HIGH FLOW AREA FILTER CLOTH MULTIPLE PIPES AGGREGATE Fia- HIGH FLOW AREA •FILTER CLOTH MULTIPLE PIPES AGGREGATE FILL PER M AG. SPECIFICATIONS FILTER CLOTH TEMPORARY ACCESS CULVERT Source: California Storm Water BMP Handbook, Construction Activity, March 1993. BEST MANAGEMENT PRACTICES FOR SAN DIEGO COUNTY - 1998 4-56 4.0 BEST MANAGEMENT PRACTICES FOR EROSION AND SEDEVl^rrCONTROL 4.3.3-b Temporary Stream Crossing SURFACE FLOW , DIVERTED BY SWALE AGGREGATE BED OVER FILTER CLOTH AGGREGATE APPROACH 5:1 MAXIMUM, SLOPE ON ROAD SURFACE FLOW DIVERTED BY SWALE WATER LEVEL SURFACE FLOW DIVERTED BY SWALE ORIGINAL STREANI BED FILTER CLOTH TEMPORARY ACCESS FORD Source: California Storm Water BMP Handbook, Construction Activity, March 1993. BEST MANAGEMENT PRACTICES FOR SAN DIEGO COUNTY - 1998 4-57 4.0 BEST MANAGEMENT PRACTICES FOR EROSION AND SEDIMENT COrOTROL 4-4.l-a Earth Dikes COMPACTED FILL • 2:1 SLOPE OR FU^TTER. BOTH SIDES GRADE LINE- B STABILIZATION AS REQUIRED ON STEEP SLOPES EXCAVATE TO PROVIDE REQUIRED FLOW WIDTH AT FLOW DEPTH DIKE 1 DIKE 2 (5 ACRES OF LESS) (5-10 ACRES) A-DIKE HEIGHT 18" 36" B-DIKE WIDTH 24" 36" C-FLOW WIDTH 4' 6' D-FLOW DEPTH 8" 15" TEMPORARY DIVERSION DIKE Source: California Storm Water BMP Handbook, Construction Activity, March 1993. ,-,-T»T> A r-TTr-fc irrkP «; AN T^nrno roilNTY- 1998 4-<;6 4.0 BFST MANAGEMENT PRACTICESFOR EROSION AND SEDUVIENTCONTROL^ 4.4.2-a Temporary Drains and Swales BEST MANAGEMENT PRACTICES FOR SAN DEEGO COUNTY - 1998 4.0 BEST MANAGEMENT PRACTICES FOR EROSION AND SEDIMENT CONTROL 4.4.3-c Slope Drain BEST MANAGEMENT PRACTICES FOR SAN DEEGO COUNTY - 1998 4-78 4.0 BEST MANAGEMENT PRACTICES FOR EROSION AND SEDIMENT CONTROL r 4.4.3-d Slope Drain ALTERNATE: SEDIMENT TRAP (SEE BMP 4.5.6) 11 lz=:i I '- LENGTH AS NECESSARY TO GO THRU DIKE I .H= D+12* PIPE ELBOW WATERTIGHT CONNECTING BAND FLEXIBLE PIPE 6- MIN. CUTOFF WALL 4- MIN @ LESS THAN 1% SLOPE SEDIMENT TRAP RIPRAP SHOULD CONSIST OF 6' DIA STONE PLftCEDAS SHOWN. DEPTH OF APRON SHOULD EQUAL THE PIPE DIAAND RIPRAP SHALL BE AMINIMUM OF 12" IN THICKNESS V / o 3D to / \ ALTERNATIVE SFOIMFNTTRAP: RIPRAP PLAN PIPE SLOPE DRAIN (FLEXIBLE) Source: California Storm Water BMP Handbook, Construction Activity, March 1993. BEST MANAGEMENT PRACTICES FOR SAN DEEGO COUNTY - 1998 4-79 4.0 BEST MANAGEMENT PRACTICES FOR EROSION AND SEDIMENT CONTROL 4.4.4-a Ouflet Protection La = LENGTH OF APRON do = INSIDE PIPE DIAtvlETER w = APRON WIDTH d = APRON THICKNESS PLAN La TJ FILTER FABRIC —-""^y^FCTIGN A-A PIPE OUTLET TO FLAT AREA WITH NO DEFINED CHANNEL NOTES: 1 APRON LINING MAY BE RIPFIAP, GROUTED REPRAP. OR CONCRETE. 2 PIPE DIAMETER. APRON DIMENSIONS. ANO AVERAGE ROCK SIZE FOR RIPRAP ARE BASED ON THE DESIGN FLOW RATE ANO VELOCITY. La AND ROCK SIZE MUST BE SET TO SLOW THE FLOW TO NON-EROSIVE VELOCITIES (e.g.. LESS THAN 10 Ips). SEE CALTRANS AND LOCAL AGENCY DESIGN CRITERIA FOR APPROPRIATE SIZING CRITERIA. 3 d = 1 5 TIMES THE MAXIMUM ROCK SIZE DIAMETER BUT NOT LESS THAN 6 INCHES- FILTER FABRIC SECTION B-B PIPE OUTLET TO WELL-DEFINED CHANNEL Source: PIPE OUTLET CONDITIONS California StormWater BMP Handbook, Construction PIPE OUTLET CONDITIONS Activity, March 1993. J K^AisJAr-piN-nriMTPRArTirFS FOR <;AN nTF.GO COUNTY-1998 4-82 4.0 BEST MANAGEMENT PRACTICES FOR EROSION AND SEDIMENT CONTROL 4.5.4-a Brush or Rock Filter (TREE/RESIDUAL MATERIAL WITH DIAMETER > 6") 1.EXGAVATEA4'X4-TRENCH ALONG THE UPHILL EDGE OF THE BRUSH BARRIER. 2. DRAPE FILTER FABRIC OVER THE BRUSH BARRIER AND INTO THE TRENCH. FABRIC SHOULD BE SECURED IN THE TRENCH WITH STAKES SET APPROXIMATELY 36" O.C. 3. BACKFILL AHD COMPACT THE EXCAVATED SOIL. 4. SET STAKES ALONG THE DOWN- HILL EDGE OF THE BRUSH BARRIER, AND ANCHOR BY TYING TWINE FROM THE FABRIC TO THE STAKES. CONSTRUCTION OF A BRUSH Source: | BARRIER COVERED BY Va. DSWC [ FILTER FABRIC T>r, A r~rir-irc Trr>R «;AN nnrr:r» rniiNTY- 1998 4-1Z5 4.0 BEST MANAGEMENT PRACTICES FOR EROSION AND SEDIMENT CONTROL 4.5.6-a Sediment Trap r SEDIMENT TRAP Small temporary basins formed by excavation or embankment can intercept sediment-laden runoff and retain the sedimenL The purpose of a sediment trap is to prevent sediment from continuing down the slope. Because sediment traps can full quite rapidly, thsy must be inspected, maintained, and cleaned out frequently. Plan their locations so that they will be accessible to construction equipment for maintenance. Sediment traps should discharge sediment-free water into a stable watercourse. /fy UNDISTURBED PERIMETER DIVERSION AND SEDIMENT TRAP Source: Unknown J BEST MANAGEMENT PRACTICES FOR SAN DIEGO COUNTY - 1998 4-137 4.0 BEST MANAGEMENT PRACTICES FOR EROSION AND SEDUVIENT CONTROL 4.5.6-b Sediment Trap VARIABLE 67 CU. YDJACRH 67 cu. tOJACRE (EXCAVATED) VARIABLE FILTER CLOTH \ ORIGINAL GROUND ELEV. •SEE PLATE 3-l3-t COARSE AGGREGATE-CLASS I RIPRAP CROSS SECTION OF OUTLET ClASS IRIPPAP LENGTH (IN FEET) = 6 X DFIAINAGE AREA (INAC) DIVERSION DIKE "COARSE AGGREGATE SHALL BE VDOT «3. i(357 OR (!5 OUTLET (PERSPECTIVE VIEW) TEMPORARY SEDIMENT TRAP Source: Va. DSWC BEST MANAGEMENT PRACTICES FOR SAN DIEGO COUNTY - 1998 4-138 4.0 BEST MANAGEMENT PRACTICES FOR EROSION AND SEDIMENT CONTROL 4.5.7-a Sediment Basin SmiMENTBASiN A sediment basin is a temporary excavation or embankment designed to intercept sediment-laden mnoff and to trap and retain sedimenL Tbese strictures can handle larger flows than sediment traps, and have a life of up to 36 months. Permanent basins (designed to function longer than 36 months) may also be used, and musl be designed to conform to construction and performance criteria appropnate for permanent stmctures. Temporary sediment basins may be used ONLY IF: 1 Failure of the structure wouki not resuH in loss of life or intenuption of use or sen/ice of public utilities, AND 2. The drainage area is less than 100 acres, AND.... 3. The water surface at the crest of the emergency spillway does not exceed 5 acres. Sediment basins which do not meet any of the above three criteria should be considered permanent stmctures, and should be designed as such. . EMERGENCY SPILLWAY STONE FILTER SPILLWAY OUTLET . WITH ANTl-SEEP COLLARS SEDIMENT BEARING STORM WATER RUNOFF y WATER IS RETAINED. VELOCITY IS SLOWED ANO SOIL PARTICLES SETTLE TO THE BOTTOM. 3ffeitai.ta»iia<gii\aiiff.memife»uJ---e«-'-t=-' '»"Q8^ • PERFORATED RISER PIPE RIP RAP.-^' TO PREVENT SCOURING 1 PROFILE THROUGH Source: 1 Unknown EMBANKMENT SEDIMENT BASIN BEST MANAGEMENT PRACTICES FOR SAN DIEGO COUNTY - 1998 4-143 APPENDIX 5 Post-Construction Treatment Control BMPs T:\Water Resources\1325-Bressi-Poimsettia\Waicr QuaUty\I325WQ-city.doc BMP: STORM DRAIN SYSTEM SIGNS Program Etom«nts __N9W Oervelopm«nt^ Residential "^orrmarciml Activities' fndustri*/ Act 'ivrtias, <CMunk:ipml Fac;7ft^> (^jj^il DtMchmrM^ DESCRIPTION ^ , . u StencUing of thc storm drain system (inlets, catch basins, channels, and crcclcs) with prohibitive language/graphic icons discourages the illegal dumping of unwanted materials. APPROACH ^ , «r Create a volunteer work force to stencil stonn drain inkts, and use mumapal staff to erect signs near drainage channels and creeks. For a quick reference oo disposal alternatives for speciHc wastes, see Table 4.1. SC50, Illegal Dumping Cootrol. REQUIREMENTS Cost Consideiatioos - Volunteer work force serves to lower program cost. . Stenciling kits require ptocurcmctH of durable/disposable items. - Need for storage/maintenance of stenciling kits requires planning. - Program can aid in the cataloging of thc storm drain system Regulations - Dcvekjp and enfbrccan-ordinancc-that requires inlets, caich basins, channels, and creeks to bc fitted with anti-dumping. poUutioa prcventioo signs. Administrative/Staffing - Primary staff demand is for program scti?) to provide marketiiig and training. - Oogoing/foUow-up staff time is minimal because of volunteer services. - Minimum 2 persons are required for high traffic areas, commercial and industrial zoocs. - Staff requiiement at program headquarters for emergencies, questions, etc. Equipment Storm drain steixnling kits. Training - Training sessions of approximately 10-15 minutes will cover stenciling proce- dures, including how to stencil, record keeping, problem drain notation, etc. - Proper health and safety protocol (buddy system, traffic health concerns, etc.). PUBLIC EDUCATION/PARTICIPATION Promote volunteer services (individual and busmess) through radio/televisioo and maU- out campaigns. PubUc reporting of improper waste disposal by a HOTLINE numbcr stcocikd onto thc storm drain inlcL I Targ«t«d Constituonts % Sedimwtt 0 Nutrients O HekvyUetMls # Toxic Materials • Fhat^le Materials # Oxygen Demand- ing Suljstmnces # Oil A Grease O B»cterim A Viruses # UkalYtoHav« SlgnlUeant Impact O Ptvbabh Low or Unknown Impact lmpi«m«ntation R*quir«ni«nts O Capital Costs Q OAM Costs O Regulatory O Staffing Q Training O Administrative High O Low SC30 Best' Management Practices'' Municipal Handbook 4 - 23 March, 1993 5. TREATMEm'CONTROL BMPs INTRODUCTION This chapter describes specific treatment control Best GENERAL PRINCIPLES There are several general principles that are applicable to all treatment Management Practices (BMPs) for removing pollutants in storm water frora urbanized areas. Each fact sheet contains a cover sheet with: A description of thc BMP Suitable Applications Selection Criteria Limitations Design and Sizing Considerations Construction/Inspection Considerations Maintenance Requirements Cost Considerations The side bar presents inforraation on which BMP considerations, targeted constituents, aixl an indication of the level of effort and costs to implement The remaiiKkr of thc fact sheet provides fiuther information on some or all of these topics, and provides references for additional guidelines. BMP fact sheets are provided for each of the following controls: control BiVfPs. Treatment Control BMPs TCI Infiltration TC2 Wet Poods TC3 Constructed Wetlands TC4 Biofllters TCS Extended Detention Basins TC6 Media Filtratioo TC7 OilAVater Separators and Water Quality Inlets TCS Multiple Systems Priority should be given lo source control: Source control BMPs are generally (but not always) less expensive than treatment control BMPs. Also, treatment control BMPs will not remove all pollutants and their removal efficiency is difficuU to predict given the Limited understanding of the relationship berween facility design criteria and performance. Recognize the unique California climate: With few exceptions most storm water treatment experience has been in "wet" states where vegetation can be maintained without irrigation. In contrast, California's climate is semi-arid with die exception of the north coast. The treatment control BMPs that require vegetative cover may not \x. practical for many areas of CaUfomia unless irrigation is provided- Also, design criteria have emerged from research of facilities located in climates where the rainfall season is coincident wiih the growth of vegetation. However, in Califomia. thc wet season does not occur during the primary growth season. Caution must \x. used in using design criteria that have h)ccn developed elsewhere in the nation. Design Storm Size: It is commonly thought by those unfamiliar with urban runoff quality management that design storms for sizing water quality controls should be the same as those used for the design of drainage facilities. This is not true. The damage done to a receiving water by the pollutant wash-off of a 25 year storm (commonly used to size a drainage system) is inconsequential to the Municipal Handbook 5 - I March, 1993 BMP: INFILTRATION RuxTff ^Environmental Side ^-^^Effects DESCRIPTION A family of systems in which the majority of the runoff from small storms is mfiltrated mto the ground rather than discharged to a surface water body. Infiltratioo systems include: ponds, vaults, trenches, dry wells, porous pavemenu and concrete grids. EXPERIENCE IN CALIFORNIA Infiltration poods have been used by many local jurisdictions and CalTrans in the Central Valley for about three decades. SELECTION CRITERIA Need to achieve high level of particulate and dissolved pollutant removal. Suitable site soils and geologic cooditioos: low potential for loog-term erosioo in tbe watershed. Multiple management objectives (e.g., ground water recharge or ninoff volume control). LIMITATIONS Loss of infiltrative capacity and high maintenance cost in fme soils. Low removal of dissolved pollutants in very coarse soils. Not suitable oo fill sites or steep slopes. Risk of ground water cootaminatiOQ in very coarse soils, inay require ground water mooitoring. Shoukl not use until upstream drainage area is stabilized. Inflitration facilities could £aU under Chapter 15, Title 23, of Califonua Code of Regulatioos regarding waste disposal to land. DESIGN AND SIZING CONSIDERATIONS • Volume sized to capture a particular Cractioa of annual runoff. Pretreatment in fme soils. • Emergency overflow or bypass for larger storms. • Obscrvatioo well in trendies. CONSTRUCTION/lNSPECnON CONSIDERATIONS • Protca infiltratioo suiface during coostructioo. • Vegetation of pood sides to prevent erosioa • Frequent inspcctioQ for ctogging during construction. Targeted Constituents 0 Sediment O Nutrients # Heavy Metals O Toxk: Materials 0 Floatable HAaterials % Oxygen Demand- ing Substances # Oil A Grease O Bacteria A Viruses # UkafytoHava Sigmficant Impact O Probabl* Low or Unknown Impact lmpi«(n«ntation R«quir9m«nts Q Capital Costs Q OAM Costs O Maintenance O Training High O Low TC1 Best' Management Practices^ Municipal Handbook 5 - 3 March, 1993 Aciciitional Information — infiltration Top View Riprap Outtail ^ Protection Side View Back-up Und«rdrain Pip* in Gas* ol Standing Water Prol)l*ins Source: Schueief (1987) NOTE: 1. Backup underdrain is not used in most applications because plugging occurs in soil above the drain. 2 An infiltration basin can also be excavated (typically 2 to 6 feet deep) as tong as the bottom of the basin is 3 feet above high seasonal water table. FIGURE lA. INFILTRATION BASIN Municipal Handbook 5 - 11 March, 1993 Municipal Handbook 5 - 12 March, 1993 POROUS ASPHALT SURFACE COURSE 1/2" to 3/4" Agcjreijdle asphaltic mix ?.6 lo 1" llli. km-.'. 1 yiii' .i I FILTER COURSE l/i!" Atjyreldl.' 2" Ihickness ^ RESERVOIR BASE COURSE 1" to 2" Ayyreyate Voids volume is IIL*S IIJIILHI lor runoff Reteiiliuii Thickness is liuseil un •jloidije rei|u i iL'tl < FUJO_ FABRIC M EXISTING SOIL Minimal compaclion lu relain porosity and permeahllily Source: Cily ol Rockville, Maryland FIGURE ID. POROUS ASPHALT PAVING TYPICAL SlXri lON a. Q. •-••* o* —K o —I 3 cu o' [ Additional Information — infiltration Poured-fn-?l*ce Slab Castellated Unic Lattice Unit Modular Unit Source: State of Florida FIGURE IK TYPES OF GRID AND MODULAR PAVEMENTS Municipal Handbook 5 - 15 March, 1993 Additional Information — wet ponds S^or features of a wet pond arc shown in Figure 2A. It is essentially a small lake with rooted wetland vegetation along the penmeter Tbe pennanent pool of water provides a quiescent volume for conunued settling of paruculaie contaminanii and uptake of dissolved contaminants by aquauc plants between stonns. The wedand vegetauon is present to improve thc removal of dissolved cootaminants and to reduce thc fonnaaon of algal mats. However, given the need to minimize thc impaa on space, it may bc cost-effecuvc to use vcrucal concrete retaining walls wbich would not allow for emergent vegetation. Thc average dcpdi of the wet pool is generally 3 to 9 feet, although greater depths arc possible with aruficiai mixmg. The objective is to avoid thermal stratification that could result in odor problems. Gentle arufiaal mixing may be needed in small poods because they are effectively sheltered from thc wind. Thc wet pond could bc aUowcd to dry during the summer months. AUowing the wet pond to dry has not been tned elsewhere but seems feasible since thc pood need not operate during the summer mooths. Thc major problem with this concept will likely be acsdieucs rather than performance. Wet poods are of interest where the removal of the dissolved constituent fraction is of concern, particulariy nutrients and nietals. Dissolved cootaminants are removed by a combinatioo of processes: physical adsorption to bottom sediments and suspended fine sediments, natural chemical flocculatioo, and uptake by aquauc plants. A wet pood witii concrete sides and floor would tiierefore not likely provide any advantage over die noo-vcgetativc treadnent control BMPs. Thc relative importance of each mechanism is not well understood. Very Umited data prevents a definitive cooclusioo as to die effectiveness of wet poods in removing dissolved contaminants. Reductioo in thc dissolved fractioo of phosphorus and some metals have been observed but this does not necessarily mean it is removed in the pood. It may be incorpo- rated into algae or absorbed ooto fme particulate mader which exits die facility in tbe effluent If die primary removal mechanism is biological, wet poods may not bc particulariy effective in removing dissolved cootaminants in California because most storms occur during winter when plant growth is minimaL Wet pood may bc preferred where the secondary objective of aesthetics or passive rccrcatioo is fanpottant. Thc rooted vcgctatioo aloog die pood edges will provide some habitat for wedand animals. Wet poods are generally not feasible m dense urtjan areas due to die uoavailabUity of land unless a park or open space is available and thc pood can bc designed to achieve rccreatiooal or acsdietic objectives. Wet poods may have several side effects that may be coosidcred unac- ceptable in certain situatioos. Placed in residential devctopmcnts, die wet pool may be coosidcred a safety hazard for small chiWrcn altiiough die incidence of drowning is rare where diesc facilities are in place. Fencing tiie facility for protccuoo can bc acsdictically dispteasing and diminishes die value of die pood for passive nxreatioa Anodier concept is die exiended detentioo wet pood in which die oudet of the facility is restricted so as to re^aina Bcamicnt design storm oo top of die wet pool for a specified time. It is believed diis added measure unprovcs perfor- mance. Tbe effea of restricting die outflow is to reduce thc overflow rate during die storin increasing tiic capmre of settieable solids. However, die migority of settiing occurs between radier dian during die stonns. Thc extended deten- tion zone may dierefore provide Uulc mcrcmcntal bcnefiL If vatkal space is avaiiable die concept could be employed because die added cost may bc nooiinal. Sec TCS Extended Detention Basins oo how to detennine die extended deten- tion volume. Drsipi Two medwds have been proposed for die sizing of wet poods: one predicated oo die removal of particulate cootaminants only (USEPA 1986) and ooc predicated oo die removal of pbospbonis as wcU (Rorida, 1988; Maryland, 1986). Thc first mediod relates die removal efficiency of suspended soUds to pood volume. The second mediod provides a deienooo Municipal Handbook 5 . 17 March, 1993 BMP: BIOFILTERS CHECK OAM Consid«rations CjoiiT^ C^^fer Availabil^^ Aesthetics Hydraulic Head Environmental Side Effects DESCRIPTION Biofdters are of two types; swale and strip. A swale is a vegetated channel diat treats concentrated flow. A strip treats sheet flow and is placed parallel to die contributing surface. EXPERIENCE IN CALIFORNIA No biofilteis specificaUy designed to treat storm water have been located. However, instances of "biofdter by happenstance" exist in nonhcni communities (Davis, Sacramento. Turiock. Fresno) wbere storm water is discharged to a grassed area prior to an inlet or an infiluatioo area. SELECTION CRITERIA Comparable performance to wet poods and constmcted wetlands. Limited to treating a few acres. Availability of water during dry season. LIMITATIONS Poor perfonnance has occurred bot diis appeals to bc due to poor design. May be limited to areas whae summer irrigatioo is feasible. Can be difficult to fnamtain sheet flow in strips. Can bc difficult to avoid channclizatioo in swales. Cannot be placed oa steep slope. Area required may make infeasible oo industrial sites. Proper maintenance required to maintain hcaldi and density of vegetalioa. DESIGN AND SIZING CONSIDERATIONS The surface area is defined by Figure 4 A. The minimum width for a swale is determined by Mannings Equatioo. Minimum length of a strip is 10 fecC Thc longitudinal slope must not exceed 5%. Use a flow spreader aod energy dissipator at the eotraoce of a swale. Good soUs are important to achieve good vegetation cover. CONSTRUCnONANSPECnON CONSIDERATIONS Make sure soils are suitable for bealdiy vcgctatioo. Level cross-sectioo and even kxigitudinal slope for swaks. Achieve sheet flow widi strips. "argetad Constituants % Sediment Q Nutrients Q Heavy Metals O Toxk: Materials Q Floatable Materials 9 Oxygen Demand- ing Substa(tc«a O Oil A Grease O Bacteria A Viruses • UkatvtoHava Significant knpact O Probabh IJOW or Unknown Impact I mplanMH tation Requiraments Q CapHal Costs Q OAMCoata Q Maintenance O Training High O Low TC4 Municipal Handbook 5-32 Best Managemenl Practices'^ March, 1993 BMP: EXTENDED DETENTWN BASINS Higr>-Wat«r L:nc FLOW 'TriiciTSbnts Co ns<d« rations Soils d^rea Required^ Shpe Water Availability Aesthetes C^H^raulic Environmental Side Effects DESCRIPTION Exiendcd detention basins are dry between storms. During a storm die basin fills. A bottom oudet releases die storm water slowly to provide time for sediments to seolc. EXPERIENCE IN CALIFORNIA There are no known extended detention basins m California. Hydraulic detention basins may function like extended detentioo basins if die former has been sized to cootrol die pre- devclopmcot 2-ycar event More liberal standards do not provide sufficient detentioo time. SELECTION CRITERIA Objective is to remove ooly particulate poUutants. Use where lade of water prevents die use of wet poods, wetiands or biofdters. Use where wet poods or wetiands would cause unacceptable mosquito cooditioos. LIMITATIONS • May be less reliable than other treatment cootrol BMPs. • Inability to vegetate banks and tottom may result in erosioa and rcsuspcnsioa • Umitatioo of die orifice diameter may preclude use in smaU watersheds. • Requires differential elcvatioo between inkt and oudet • Pending their volume and depth lasin designs may require approval from State Division of Safety of Dams. DESIGN AND SIZING CONSIDERATIONS Basin volume is sized to capture a particular fraction of the runoff. E>rawdown time of 24 to 40 hours. ShaUow basin widi large surface area performs better tiian deep tasin widi same volume. Place energy dissipators at thc entrance to minimize Ixjttom erosioo and resuspension. Vegetate side slopes and bottom to die maximum extent practical. If side erosion is particularly sevcic, coosidcr paving or soil stabilization. If floatables are a problem, protect oudet widi trash rack or odier device. Provide bypass or pass dirough capabilities for 100 year storm. CONSTRUCnONANSPECnON CONSIDERATIONS • Make sure thc outiet is instaUed as designed. Targeted Constituents 0 Sediment Q Nutrients Q Heavy Metals O Toxh Materials Q Fksatable Materials Q Oxygen Demand- ing Substances O Oil A Grease O Bacteria A Viruses # UkafytoHava SlgnlUeant Impact O Probable Low or Unknown Impact Implementation Requirenvants 0 Capital Costs Q OAMCoata O fl4alntenanca O Training High O Low TCS Best' Management Practices'' Municipal Handtiook 5-39 March, 1993 Manicipal Handbook 5 - 56 March, 1993 Municipal Handbook 5 - 57 March, 1993 BMP: MULTIPLE-SYSTEMS iFLOW INRtTRATION ^.it TRENCH INFltTRATION BASIN Considorations Soils <CA^^equi^d^ Cs^^ <CWaterAvailabU^^ Aesthetics C^draulic He^^ Environmental Side Effects DESCRIPTION A multiple treatment system uses two or more of the preceding BMPs in scries. A few multiple systems have already been described: settling basin combined with a sand filter, settling basin or biofdter coaibincd with ao iofUtratioo basin or trench; extended detentioo zooe 00 a wet pood. EXPERIENCE IN CALIFORNU • Thc research wetlands at Fremoot, Califorma are a combinatioo of wet poods, wetlands, and grass biofilters. SELECTION CRITERIA • Need to protect a downstream treatment system • Enhanced reliability • Optimum use of the site LIMITATIONS • Available space DESIGN AND SIZING CONSIDERATIONS • Refer to individual treatment cootrol BMPs CONSTRUCTION/INSPECnON CONSIDERATIONS • Refer to mdividual treatment cootroi BMPs MAINTENANCE REQUIREMENTS • Refer to individual treatment cootroi BMPs COST CONSIDERATIONS Targeted Constituents 0 Sediment W Nutrients Q Heavy Metals O Toxh Materials • Fktati^le Materials Q Oxygen Demat*d- ing Substances O Oil A Grease 9 Bacteria A Viruses 9 UkafytoHava Significant knpact O Prob^hLowor Unknown Impact implementation Requirements # Capital Costs 9 OAU Costs O Maintenance O Training High O Low TCS Best' Management Practices'' Municipal Handbook 5-68 March, 1993 BMP: OIUWATER SEPARATORS AND WATER QUALTTY INLETS FLOW Cor^siderations So/7« C^Area Requir^^ Sk}pe Water Availability Aesthetics Hydraulic Head Environmental Side Effects DESCRIPTION Oil/water separators are designed to remove ooe specific group of contaminaats: petroleum compounds and grease. However, separators wUl also remove floatable ddiris and settle- able solids. Two general types of oil/water separators are used: cooventiooal gravity separator and die coalescing plate interceptor (CPD. EXPERIENCE IN CALIFORNU Oil/water separators are in use throughout CaUfomia at industrial sites. Oil/water separa- tors are used at aU bulk petroleum storage and refinery faciUties. A few jurisdictions require new commercial developments to instaU separators under ceitain situatioos that are environmentaUy sensitive. SELECTION CRTTERU AppUcable to situations where die coocentratioo of oil and grease related compounds will be aboormaUy high and source cootrol cannot provide effective cootrol. The general types of businesses where diis simatioo is Ukely are Buck, car, and equipment maintenance aod washing businesses, as weU as a business that performs maintenance oo its own equipment and vehicles. PubUc faciUties where separators may be required include marine ports, airfiekls, fleet vehicle maintenance and washmg, fadUties, and mass transit park-and-ridc lots. Conventional separators are capable of removing oU droplets witfi diametos equal to or greater than 150 microos. A CPI separator should bc used if smaUer droplets must be removed. LIMTTATIONS • Litde data oa oil characteristics in storm water leads to coosiderable uoccnainty about pciformance. • Air quaUty pennit (cooditiooal authorizatioa) peimit-by-rule from DTSC may be required. DESIGN AND SIZING CONSIDERATIONS • Sizing related to anticipated influent oil coocentratioo, water temperature and veiodty. arxl die effluent goaL To tnamrain reasotiablc separator size, it should be designed to bypass flows in excess of first flush. CONSTRUCTION/INSPECnON CONSIDERATIONS • None identifled. MAINTENANCE REQUTREMENTS • Clean frequendy of accumulated oiL grease, and floating debris. COST CONSIDERATIONS • Coalescing plate material is cosdy but requires less space than tiie cooventiooal seyaniot. Targeted Constituents O Sediment O Nutrients Q Heavy Metals O Toxh Materials # Fhatable Materials 9 Oxygen Demand- ing Substances # Oil A Grease O Bacteria A Viruses • UkafytoHava Significant knpact O Probabh Low or Unknown Impact Implementation Requirements Q Capital Coata O OAU Costa 9 Maintenance O Training High O Low TC7 Best' Management Practices^ Municipal Handbook 5 - 59 March, 1993 APPENDIX 6 Post-Construction Proprietary BMPs T:\Waier Resources\1325-Brcssi-Pointsettia\Water Quality\I325WQ-ciey.doc I I I 1 CDS is the most effective system for tlie sustainable removal and retention of suspended solids aind floatables from storm water. REMOVES POLLUTANTS The Continuous Deflective Separation (CDS) technology utilizes a non-blocking, non-mechanical screening process to remove pollutants from storm water flow and combined sewer overflows (CSO). CDS units capture fine sands and solids and are capable of removing more than 80% of annual total suspended solids from storm water. Additionally, CDS units remove 100% of floatables and 100% of all particles in the storm water which are equal to or greater than one-half the size of the screen opening. Studies show the units remove 93% of all particles which are one-third the size of the screen opening, and 53% of all particles one-fifth the size of the screen opening. A conventional oil baffle within a CDS unit effectively controls oil and grease in storm water. With the addition of sorbents, the permanent capture efficiency of oil and grease is increased to 80-90%. The combination of a conventional oil baffle and particulate sorbents is a unique feature of a CDS storm water treatment unit. Once pollutants are captured in a CDS unit, they cannot escape. PROVEN TECHNOLOGY The CDS technology has been proven by extensive independent laboratory studies and hundreds of actual installations in the United States and Australia. Copies of these performance reports are available at our web site, or by contacting our offices. APPROVED BEST MANAGEMENT PRACTICE The CDS technology has achieved approval as a Best Management Practice (BMP) by municipalities and state DOTS throughout the United States. The USEPA lists CDS as a structural BMP. ® Manufaclure Material Model Designation Approximate Impervious Catchment Area (Acres) Treatment Capaciiy Q water qualily Screen Diameter/Heiglit (ft) Sump Capaciiy (yd3) Deplli Beiow Pipe Invert (ft) Foot Print Diameter (fl) Manufaclure Material Model Designation Approximate Impervious Catchment Area (Acres) cis MGD Screen Diameter/Heiglit (ft) Sump Capaciiy (yd3) Deplli Beiow Pipe Invert (ft) Foot Print Diameter (fl) Precast Concrete PMSU 20_15 1-4 0.7 0.5 2.0/1.5 1.1 5.1 6.0 Precast Concrete PMSU 20_20 2-6 1.1 0.7 2.0/2.0 1.1 5.7 6.0 Precast Concrete PMSU 20_25 3-9 1.6 1.0 2.0/2.5 1.1 6.2 6.0 Precast Concrete PSW & PMSU 30_28 6-17 3.0 1.9 3.0/2.8 1.4-2.1 6.9 6.0-6.5 Precast Concrete PSWC & PMSU 40 40 12-33 6.0 3.9 4.0/4.0 1.9 9.7 8.3 Precast Concrete PSWC 56_40 & 50_40 & 50_50 18-61 9 & 11 5.8 & 7.1 5.6 / 4.0 & 5.0/5.0 1.9 9.7 9.5 Precast Concrete PSWC 56_53 28-78 14 9 5.6/5.3 1.9 10.8 9.5 Precast Concrete PSWC 56_68 38-106 19 12 5.6/6.8 1.9 12.5 9.5 Precast Concrete PSWC 56_78 & PSW 70_70 50-144 25&26 16&17 5.6 / 7.8 & 7.0/7.0 1.9-3.9 13.5 9.5 Precast Concrete PSW100_60 60-167 30 19 10.0/6.0 6.9-14.1 12.0 17.5 Precast Concrete PSW100_80 100-278 50 32 10.0/8.0 6.9-14.1 14.0 17.5 Precast Concrete PSW 10OJ 00 128-356 64 41 10.0/10.0 6.9-14.1 16.0 17.5 Fiberglass Premanufactured fiberalass units are avaiiabie to treat small flows Of 1 to 3 c fs Cast-ln-Place Concrele CDS cast-in-place reinforced concrete units can be designed to treat flows up to 300 cfs 1) Raw storm water enters the CDS unit's diversion chamber (z) A diversion weir guides the flow into the unit's separation chamber where a vortex is formed. ® The vortex spins all floatables and most suspended solids to the center of the separation chamber. ® )The separation screen will not become blocked due to the washing vortex, but it will allow liquid to move through. (^The screened liquid which passes through the process quickly moves toward the outlet. v: @)The diversion weir is designed to bypass exce.5sive flows without affecting the proper operation of the CDS unit or storm drain system. Bypass flows will not wash out any of the captured pollutants. (9)The cleaned water then moves • freely to the receiving water. (8)The cleaned storm water moves out of the separation chamber and into the diversion chamber downstream from the diversion weir. ; )The sump can be equipped with an optional basket to facilitate emptying the unit, or simply clean with a vactor or clam bucket. 6) Suspended solids gently settle into a sump where they remain until they are removed. EXTREMELY LOW MAINTENANCE CDS units are self-operating. They have no moving parts and they are entirely gravity driven, requiring only the hydraulic energy available within the storm water flow. The screens and supporting hardware are stainless steel and will resist corrosion. CDS units have very large sump capacities relative to their design flows, and only need to be cleaned out with a standard vactor truck approximately one to four times per year. This operation eliminates workers' exposure to the materials captured in the units. KEY FEATURES and BENEFITS Uses • Storm Water Treatment • Combined Sewer Overflow Treatment • Dry Weather Flow Diversion Applications • Capture and retention of suspended solids, sand, floatables, oil and grease, and other gross pollutants from: • Commercial Service and Parking Areas • Industrial Areas • Public Property and Parkland • Residential Streets and Private Property • Pretreatment for: • Wetlands, Ponds, and Swales • Media and Sand Filters • Oil/Water Separators Efficient • Highly effective (up to 90%) in capturing and retaining sediment as small as one- third the screen aperture. • Captures and retains 100% of floatables and all other material greater than the screen aperture. Cost-Effective • CDS provides the lowest cost per CFS (Cubic Feet per Second) processed when compared to other structural BMPs. Large Flow Range • From 0.7 to 300 CFS. Non-Blocking and Non-Mechanical • Standard CDS units have no moving parts. They require no power or supporting infrastructure, and they will not clog. Unobtrusive and Easy lo Install • CDS units are compact and are installed below ground, so space requirements are modest. They are ideal for new construc- tion as well as retrofit or redevelopment. Low-Cost, Safe and Easy Pollutant Removal • Maintenance is easy using standard vactor. clam, or basket equipnient which mini- mizes maintenance personnel exposure to hazardous material. Improves Discharge Wafer Qualily • Removes floatables and suspended solids from storm water runoff. • Removes free oil and grease with the use of an oil baffle, and/or sorbents