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Home My WebLink AboutCDP 05-19; TOYOTA CARLSBAD; STORM WATER MANAGEMENT PLAN DWG 441-6A; 2005-04-08^ STORM WATER MANAGEMENT PLAN for Toyota Carlsl 6030 Avenida Encinas City of Carlsbad f CDP 05-19/lDWG. NO. 441-6A Prepared for: Stellar Properties, LLC 5424 Paseo Del Norte Carlsbad, CA 92008 Prepared By: bhA, inc. land planning, civil engineering, surveying 5115 Avenida Encinas, Suite L Carlsbad, CA 92008-4387 (760) 931-8700 April 8, 2005 Revised November 20,2006 Revised April 13, 2007 Revised May 07,2007 W.O. 591-0804-605 TABLE OF CONTENTS INTRODUCTION Project Description Pollutants and Condition of Concern ESTABLISH PERMANENT STORM WATER BEST MANAGEMENT PRACTICES Site Design BMPs Source Control BMPs BMPs Applicable to Individual Priority Project Categories Treatment Control BMPs OPERATION AND MAINTENANCE PROGRAM NUMERIC SIZING OF BMPs REFERENCE ATTACHMENTS 1. Vicinity Map 2. Site Map 3. Storm Water Requirements applicability Checklist INTRODUCTION 1 INTRODUCTION A Storm Water Management Plan (SWMP) is required under the City of Carlsbad's storm water management requirements. According to the Storm Water Requirements Applicability Checklist, this project is subject to Priority Project Permanent Storm Water BMP Requirements and Standard Permanent Storm Water BMP Requirements. The purpose of this SWMP is to describe the permanent storm water Best Management Practices (BMPs) that will be incorporated in the project to mitigate the impacts of urban runoff due to the development. This SWMP is intended to ensure the effectiveness of the BMPs through maintenance that is based on long-term planning. The SWMP is subject to revisions as needed by the engineer. 1.1 Project Description Service Facility for Toyota Carlsbad, 6030 Avenida Encinas, is located on the east side of Avenida Encinas, just south of the intersection of Avenida Encinas and Palomar Airport Road. The 9.76 acres site is zoned for industrial use. Currently, the property is being used as a body and painting facility and office building for Toyota Carlsbad. This project proposes the demolition of the office building and replacing it with a automobile service facility/parking structure and reconfiguring portion of the onsite parking spaces. 1.2 Pollutants and Condition of Concern A. Identify Pollutants from the Project Area Using Table 2, Anticipated and Potential Pollutants Generated by Land Use Type from the City of Carlsbad Standard Urban Storm Water Mitigation Plan, we have identified the anticipated and potential pollutants generated by this project. The anticipated pollutants are heavy metals, organic compounds (petroleum hydrocarbons and solvents), trash & debris, Oil and grease. Sediments, nutrients, oxygen demanding substances, and pesticides are potential pollutants of concern because this project proposes landscaping. The anticipated pollutants from the automotive repair category will be treated on-site and will not be discharged into the storm drain system. The runoff from the proposed development are treated by the proposed filtration systems at the end of the proposed storm drain system so that the runoff is filtered before exiting the site. B. Identify Pollutants of Concern in Receiving Waters This project discharges its runoff to the Encinas Hydrologic Sub-area (904.40), part of Carlsbad Hydrologic Unit (904.00). According to the California 2002 303d list pubhshed by the San Diego Regional Water Quahty Control Board, there are no impaired water bodies that are associated with this project. Service Facihty for Toyota Carlsbad's location and watersheds have been compared to the current published 303d hst of impaired water bodies. The nearest impaired water body is Pacific Ocean Shoreline at San Marcos HA (904.51). Pacific Ocean Shoreline at San Marcos HA is impaired with Bacteria. C. Identify Conditions of Concern A Hydrology and Hydraulic Report has been prepared for Toyota Carlsbad Service Facility, dated April 5,2005. As part of the drainage study, a field reconnaissance was conducted for this project. No detrimental effect was observed onsite. The existing outlet structure remains in good condition and no sign of erosion was observed. The potential of downstream erosion is minimal because the runoff from the development is proposed to be released into an existing storm drain in Avenida Encinas and the existing outlet structure remains in good condition. ESTABLISH PERMANENT STORM WATER BEST MANAGEMENT PRACTICES 2 Establish Permanent Storm Water Best Management Practices To address water quality for the project, permanent BMPs will be incorporated into the project design. Anticipated and potential pollutants of concern as noted in Table 2 will be addressed through four types of BMPs. These types of BMPs are Site Design, Source Control, BMPs for Individual Priority Project Categories and Treatment Control. A. Site Design BMPs Post-development peak storm runoff discharge rates and velocities will be controlled such that they are equivalent to or below that of the pre-project condition by incorporating the following design concepts: Minimize impervious footprint by: • Increasing building density (multi-story building): The project is proposing to increase floor area over that of the existing building by the use of a 3 story building. The new building will not add to the footprint of the original building. • Constructing driveways, parking spaces and parking lot aisles to the minimum width necessary, provided that public safety and walkable environment for pedestrians are not compromised: The project proposes to utilize the minimum size parking spaces, and minimum width drive aisles to minimize the creation of new impervious parking lot area. Also, the top level of the new building will be utilized for vehicle storage within the old existing building footprint further minimizing the creation new parking lot area. Minimize directly connected impervious area: • The project is proposing to drain 67% of the top floor vehicle storage area onto and through a landscape area that will allow treatment and infiltration prior to being conveyed to the storm drain system via surface improvements. B. Source Control BMPs Source control BMPs will consist of the following measures to prevent polluted runoff: Trash storage areas: • Trash storage areas will be enclosed, covered, and contained within the new building. All debris will be contained, and run-on from adjoining areas will be prevented. Irrigation system design and implementation: • Employ rain shutoff devices to prevent irrigation during and after precipitation event. • use flow reducers or shutoff valves triggered by a pressure drop to control water loss in the event of broken sprinkler heads or lines. • Design irrigation systems to each landscape area's specific water requirements. Provide storm drain system stenciling and signage • Provide concrete stamping and/or signage at all storm water conveyance system inlets and catch basins within the project area with prohibitive language (e.g., "No Dumping -1 Live Downstream".), satisfactory to the City Engineer. • Maintain legibility of stencils and signs. C. BMPs Applicable to Individual Priority Project Categories Dock Area: • No depressed loading dock areas are proposed for this project. Maintenance Bays: • Repair/maintenance bays are indoors. • The discharges from the maintenance bays' will be pre-filtered and released into the sanitation system. Vehicle & Equipment Wash Areas: • Areas for washing/steam cleaning of vehicles and areas for outdoor equipment/accessory washing and steam cleaning is self-contained to preclude run-on and run-off, covered with a roof or overhang, and equipped with a clarifier or other pretreatment facility; (2) properly connected to a sanitation sewer if appropriate. Where areas are connected to a sanitary sewer, an Industrial Waste Permit may be required from the Encina Water Pollution Control Facility. Surface Parking Areas: • Incorporate landscaping into drainage design when possible. The landscape area between the new building and the freeway right-of-way will incorporate a "Grassy Swale" which will intercept runoff generated on the vehicle storage parking area on the roof of the proposed new building, treat it, and convey it to the beginning of the proposed surface improvements. Non-Retail Fuehng Areas • Not Applicable D. Treatment Control BMPs The following treatment control BMPs will be implemented to address water quality. • Grassy Swale, located at the easterly boundary.( See References section for fact sheets and Numeric Sizing BMPs for the calculations.) • Media Filtration Device, Bay Filter Storm Water Filtration System by Bay Saver Technologies, Inc. It removes fine sediments, heavy metals, and phosphorus from storm water runoff. The Bay Filter System has been extensively tested, and has consistently shown more than 80% removal of suspended sediment from influent water. The system also demonstrated the capability to remove more than 50% of the total phosphorus Influent load, including a portion of the dissolved phosphorus.( See Numeric Sizing for calculations, detail and drawings.) OilAVater Separators will be installed: A modification to the Bayfilter will incorporate an oil/water separator for the northerly system. A separate oil/water separator system will be installed along with the Bayfilter for the proposed southerly system.(See Numeric Sizing for detail drawings) Placement of the BMPs are noted on the WQTR Exhibit. OPERATION AND MAINTENANCE PROGRAM 3 OPERATION AND MAINTENANCE PROGRAM For The operation and maintenance requirement see the Maintenance section of Bay Filter System Technical and Design Manual included in References Section of this report. Responsible Parfy Information: Stellar Properties 5424 Paseo Del Norte Carlsbad, CA 92008 Bob Wolf 760-497-7286 NUMERIC SIZING BMPS 4 NUMERIC SIZING CALCULATIONS FOR BMPs Bay Filter stormwater flitration system For Flow Based BMPs: Q=CIA For the South System: C=0.87 1=0.2 A=2.06 ac Q=(0.87)x(0.2)x(2.06) Q=0.36 cfs Bay Filter Stormwater Filtration System Model MHF-96-6 with 0.403 cfs is proposed For the North system: C=0.87 1=0.2 A=2.75 ac Q=(0.87)x(0.2)x(2.75) Q=0.48 cfs Bay Filter Stormwater Filtration System Model MHF-120-8 with 0.537 cfs is proposed Grassy Swale: C=0.87 1=0.2 A=1.18 ac Q=(0.87)x(0.2)x(1.18) Q=0.20 cfs The length of Swale will provide the minimum travel time of 10 minutes without increasing the depth of water more than 4-Inch(grass height). See Swale calculations included in this section. NUMERIC SIZING BAY FILTER STORMWATER FILTRATION SYSTEM BayPilter™ Sizing Report Project: Toyota of Carlsbad Location: Carlsbad, CA JfeBAYSAVE R ^^(ff TECHNOLOGIES. INC. 4/6/2007 Proposed BayFilter™ Stormwater Filtration System South System - Treatment Requirement of 0.36 cfs BavFilter^" Stormwater Filtration System IViod el lVIHF-96-6 # Cartridges Type of Cartridges Design Flow per Cartridge (GPM)(1) Fiow rate (cfs) 6 Bayfilter Cartridges 30 0.401 1 Drain Down Cartridqe 1 0.002 Total System Capacity (cfs) 0,403 North System - Treatment Requirement of 0.48 cfs BayFilter™ Stormwater Filtration System Mod el IVlHF.120-8 # Cartridges Type of Cartridges Design Flow per Cartridge (GPM)(1) Flow rate (cfs) 8 Bayfilter Cartridges 30 0.535 1 Drain Down Cartridqe 1 0.002 Total System Capacity (cfs) 0.537 (1) Design flow rate per Technical & Design Manual specifications. BayFilter^^ Filtration System Peiformance Specifications Peiformance and Operation The BayFilter''''^ has been extensively tested in the laboratory. This testing has been carried oUt using SIL-CO-SIL 106 as a sediment source. SIL-CO-SIL 106 is a silica product containing approximately 90% fine sediments {d^ = 23 microns), and is widely accepted as a sediment source for stormwater simulations by regulatory agencies such as the Washington State Department of Ecology (TAPE) program, New Jersey Department of Environmental Protection (TARP), as well as other leading agencies. The BFC needs only 28" of depth of water to begin full flow operation. Once the full flow operation has been achieved, the BFC will operate to a depth of 6" at which time the siphon wiil break and the system wiU backwash. At this point the only flow is from the Drain Down Cartridge which wHl drain the vault to a depth below 1". Each BFC has a maximum nominal flow of 30 gpm. At this flow, each cartridge can treat 150 lbs of the total sediment load before maintenance. In addition, through the use of different size flow control orifice(s), the BFC flow is regulated. As the flow is lowered, the treated sediment load increases. For example, when the flow is lowered to 15 gpm, the cartridge is able to treat 300 lbs of the total sediment load before maintenance. A chart of the flows and total sediment loads can be found on Table 1. Flow Thiough Filtration Systems These systems are used in situations where a certain flow rate must be treated. The treatment flow rate must be determined by the engineer. From this, the minimum number of BFCs is very simple to determine. Usually fuU flow systems require a large number of cartridges and because of this the maintenance cycles may be longer but more cosdy. The Hfe of the cartridges can further be extended through the use of pretreatment with a BaySeparator''"^. For these systems, use 30 gpm design flow per BFC for treated sediment loads up to 150 lbs. To use higher cartridge sediment loads of up to 300 lbs per BFC, see Table 1 for the appropriate flow-load relationships. A minimxim head of 40" (for fuU flow) is required, as measured from the floor, to achieve the 30 gpm and the target sediment removal. Higher sediment loads can be achieved by including pretreatment of stormwater. As can be seen from Table 1, the design flow rate is determined by the target amount of solids to be removed. For example, if the designer's goal is to treat a cartridge sediment load of 150 lbs at 80% efficiency, die design flow rate would be approximately 30 gpm (0.067 CFS) per BFC. In another case, if the engineer is targeting a much heavier cartridge sediment load of 250 pounds; the design flow rate per BFC would then be 20 gpm (0.045 CFS). The different sediment removal/design flow rate relationships are achieved with minimum total heads of 40 inches as measured from the floor level, where the BFCs are installed (shown in Table 1). At each design flow rate, each BayFilter"""^ cartridge will achieve a suspended sediment removal efficiency of over 80% at the rated flow rate. This 80% sediment removal efficiency is based on laboratory testing using the SIL-CO-SIL 106 sediment gradation. The BayFilter'''"^' cartridge has the capability to remove 50% of the total phosphorus load, since most of the total phosphoms is typically found in particulate form. Table 1 Design Flow per BFC-gpm Nominal Treated Sediment Load for 80% Sediment Removal - Lbs Total System Head at Design Flow - Inches 30 150 40 23 200 40 20 250 40 15 300 40 (*) Sediment witti dso = 23 microns Other key operating parameters of BayFilter"^^ systems include: 1. Minimum head for the BFC to begin full flow is 28". 2. IVfinimum head for the BFC to operate after full flow is 6". 3. Minimum water level for DDC operation is approximately 1". 4. Full flow head is at 40". BayFilter™ Systems Drawings • Plan Views • Diversion Structures BAiriLTCR STORMVATER FILTRATION SYSTEM PROTECTED BY U.S. PATENT • 6.869,528 096 4" DUTLET ENERGY DISSIPATOR/- LEVEL SPREADER 6' INLET MINIMUM PRELIMINARY REV DESCRIPTION DATE APPR NOTES; BAYSAVER I KniNOI,(X;il:S. INC. WWW.I1AVSAVHH.COM DESIGNED: TEP DRAVNi PR CHECKED: PR DATE: 03/14/07 SCALE: N.T.S. DVG N0< BF-104 TOYOTA OF CARLSBAD SOUTH SYSTEM MANHOLE BAYFILTER MODEL MHF-96-6 riLIER SrOSHWATER FILTMniM SYSTEM POOIECTCD JY US. PATENT * 6.869.SS8 O 3 ACCESS HATCH FRAME AND COVER SIPHON VEIR «20 niL/SAND SEPARATION WALL ENERGY DISSIPATOR/ LEVEL SPREADER 6' INLET MINIMUM 2?' OILS/ FLOATABLES tD D -C 01 D C m m o I z o r o n m cn n •n D X z o CO w U -sl 3 DCSCRIPTION DAIE «W NOTES; BAYSAVFJ^ TtCHKOtOOlES. DM:. •A-WW.BAVSAVEHCOM OESIGMEO: TEP DRAVNI PR CHECKED: PR DATE: 5/1/07 SCALE: N.r.S. DVG NDi BF-aOl PRELIMINARY TOYOTA OF CARLSBAD NORTH SYSTEM - OPT 1 MANHOLE BAYFILTER WITH INTERNAL OIL/SAND SEPARATOR MODEL MHF-120-8 IO Q (S -vl ro rvj Ul •3. TJ 10 BAYFILTER STORMVATER FILTRATION SYSTEH PROTECTED BY U.S. PATENT » 6,869.328 ENERGY DISSIPATOR/ LEVEL SPREADER INLET UTLET HEADER PRELIMINARY REV DESCRIPTION OATE APPR NOTES: BAYSAVER W0 TECHNOLOGIES. INC. ij.iir'iiwwi.ni.MWAinitniiimiM WWW.IIAVSAVl-.R.COM DESIGNED: TEP DRAVNI PR CHECKED: PR DATE: 03/14/07 SCALE: N.T.S. DVG NDi BF-201 TOYOTA OF CARLSBAD NORTH SYSTEM - OPT 2 VAULT BAYFILTER MODEL PVF-10-8-8 3ynionyis N0isy3Aia i^3iSAS Hinos Qvasnyvo JO VIOAOI iQN OAQ ad :a3>l03HO •SU'N :3TV0S ad iNAvaa /0/ia/eo :31VQ d3i :a3N0IS3a W03 H JAVSAVHM*.« 9 jNrsai'JonoNiDai >I3AVSAVe 9 ••S310N UddV 3iVQ N0U.diaDS3a A3U AyvNiiNn3yd SJO LCO = D NI dDH .81 ge'st' = 31 ino doa ,81 3ynionais N0isy3Aia tN31SAS Hi HON Qvasiavo io viOAOi •DN DAQ ad :a3>O3H0 •Si'N :31V0S ad iNAvaa io/is/eo :3iva d3i :a3N0IS3a WOa HHAVSAVOMMM 9 M\ •sniuoioNHDni "aHAVSAVe 9 :S310N HddVaiVQ N0lidlH3S3a A3a AyvNiiNn3ad SJO 6t''0 = 0 Oe'9t' = 31 y311IJ Di OAd .9 OO'Zt' = 31 NI dOa ,81 08'9t' = 31 ina dOd .81 Toyota of Carlsbad Carlsbad, CA Typical Oil-Sand Separator that would be incorporated as part ofthe BayFilter System. 24" CAST IRON FRAME & COVER WITH GASKET (GA5T1GHT) STANDARD- VARIABLE 16" WIN. AS REOUIRED (A T EXTKA COST) 2432-03 RISER-3" 2432-OB RISER-6" SIDE VIEW (CUT AWAY) r-o" — TOP VIEW (COVERS & RISERS REMOVED) 1 1 l/ \ , i / 1 1 ITiO cmi: 1 V 1 v_ / ! LZT: 1 1 1 ! LZT: 1 6" PVC INLET & OUTLET PIPE AND FITTINGS STANDARD 3-D" Oil/Sand Interceptor Capacity: 320 gallons H-20 Traffic Load Design NUMERIC SIZING GRASSY SWALE TRAPEZOIDAL CHANNEL ANALYSIS NORMAL DEPTH COMPUTATION April 13, 2007 PROGRAM INPUT DATA DESCRIPTION VALUE Flow Rate (cfs) .• Channel Bottom Slope (ft/ft) Manning's Roughness Coefficient (n-value) 0.25 Channel Left Side Slope (horizontal/vertical) 0.5 Channel Right Side Slope (horizontal/vertical) 0-5 Channel Bottom Width (ft) 2.0 COMPUTATION RESULTS DESCRIPTION ^^Yi^ Normal Depth (ft) Flow Velocity (fps) 0 079 Froude Number ^• Velocity Head (ft) Energy Head (ft) 0-^° Cross-Sectional Area of Flow (sq ft) ^.a/ Top Width of Flow (ft) ^-^^ HYDROCALC Hydraulics for Windows, Version 1.2a Copyright (c) 1996 Dodson & Associates, Inc., 5629 FM 1960 West, Suite 314, Houston, TX 77069 Phone: (281) 440-3787, Fax: (281) 440-4742, Email:software@dodson-hydro.com All Rights Reserved. REFERENCE 5 REFERENCE Water Quality Control Plan for the San Diego Basin (9) California Regional Water Quality Control Board, San Diego Region, September 8,1994 County of San Diego, Standard Urban Storm Water Mitigation Plan for Land Development and Public Improvement Projects, February 2003 California Stormwater Best Management Practice Handbook, Municipal, March 1993 2002 CWA Section 303(d) List of Water Quality Limited Segment, February 2003 B.WFH.T!'R™ S\ ST[,: M Technical and Design Manual © BaySaver Technologies, Inc. 1302 Rising Ridge Road, Unit One Mount Aicy, Maryland 21771 Phone 301-829-6470 • Fax 301-829-3747 Table of Contents INTRODUCTION 1 PRINCIPLES OF OPERATION.2 Media Filtration 2 Mechanisms of Removal 2 The BayFilter™ Cartridge 2 The Drain Down Cartridge Filter 4 Performance Characteristics 5 Flow Through (Full Flow) Filtration Systems 5 Post Extended Detention Filtration Systems 5 DESIGN GUIDELINES FOR THE BAYFILTER™ SYSTEM 8 BayFilterTM Treatment Train Design 8 On-line and Off-line Systems 8 Pretreatment 9 Extended Detention Systems 10 Preparing Site Plans for the BayFilter^*' System 11 Location 11 Selecting the Number of cartridges 11 Required Data 12 Flow Capacity 12 Sediment Load Capacity 13 Jurisdictional Filter Requirements 14 Summary 15 BayFilter™ System Configuration 19 Manhole BayFilter™ 19 Precast Vault BayFilter™ 21 Cast-in-place BayFilter™ 23 INSTALLATION OF THE BAYFILTER™ SYSTEM 24 Installation ofa Manhole BayFilter™...25 Installation of Precast Vault BayFilter''''^' 26 MAINTENANCE OF THE BAYFILTER™ SYSTEM 27 Maintenance Procedures 28 BAYFILTER™ SYSTEM COSTS AND AVAILABILITY 29 BAYFILTER™ DETAILED OPERATING SEQUENCE 30 GENERAL CHECKLIST FOR DESIGNING A BAYFILTER™ SYSTEM 36 Advantages and Disadvantages of System Configurations 38 SYSTEM DRAWINGS 40 BAYSAVER TECHNOLOGIES, INC. Introduction Founded in 1997, BaySaver Technologies, Inc. is a manufacturer of stormwater treatment technologies. BayFilter''"^^^' is a stormwater filtration device designed to remove fine sediments, heavy metals, and phosphorus from stormwater runoff BayFilter'^'^ relies on a spiral wound media filter cartridge widi approximately 43 square feet of active filtration area. The filter cartridges are housed in a concrete structure that evenly distributes the flow between cartridges. System design is offline with an external bypass that routes high intensity storms away from the system to prevent sediment resuspension. Flow through the filter cartridges is gravity driven and self-regulating, which makes the BayFUter'^^^ system a low maintenance, high performance stormwater treatment technology. The BayFUter'^^ system has been extensively tested, and has consistentiy shown more tlian 80% removal of suspended sediment from influent water. The system also demonstrated the capability to remove more than 50% of the total phosphoms influent load, induding a portion of the dissolved phosphorus. This manual provides detailed technical information on the BayFilter'^'^ system including its capabilities and limitations. The manual describes the steps involved in designing a BayFilter'^'^ system as well as the installation and maintenance requirements of the system. BaySaver Technologies is a complete stormwater solutions provider. We are always wiUing to assist design professionals to achieve the most efficient, economical systems for their clients and projects. Please call BaySaver Technologies Inc. Engineering Department at 1.800.229.7283 for assistance. (') The BayFilter^'^ stormwater filtration system is protected by U.S. Patent #6869528, in addition to several pending patents. BAYSAVER TECHNOLOGIES, INC. Principles of Operation The BayFilter'''^ system removes contaminants from stormwater mnoff via media filtration. This Technical and Design Manual describes the prindples by which the BayFilter'^-'^ system works to improve the quality of the environment throughout the United States. Media Filtration Media ffltration has long been used in drinking water and wastewater treatment processes. This technology has proven effective at removing sediments, nutrients, heavy metals, and a wide variety of organic contaminants. The target pollutants, hydraulic retention time, filter media, pretreatment, and flow rate all affect the removal efficiency of the filter. Mechanisms of Removal The BayFilter'^'*^ removes pollutants from water by two mechanisms: 1) interception/attachment and 2) adsorption. Interception occurs when a pollutant becomes trapped within the filter media. A sediment partide, for example, may be carried into the filter media by the water and become stuck in the interstices of the media. Such a partide will typically remain trapped witiim the media until the media is removed or the filter is backwashed. Attachment occurs when pollutants bind themselves to the surface ofthe filter media, and this happens primarily tiirough adsorption. Adsorption is a stirface process by which dissolved ions are removed from a solution and chemically bind themselves to the surface of the media. This occurs when the surface of the filter media particle contams sites tiiat are chemically attractive to the dissolved ions. The BayFilter''"" system uses a proprietary media containing activated alumina to enhance adsorption of anions such as phosphates. The BayFilter^" Cartridge The main building block of tiie BayFilter'^'^ stormwater filtration system is tiie BayFilter^'"' cartridge (BFQ, shown in Figure 1. The BFCs are housed in a stmcture which may be a vadt, manhole or otiier structure. This structure contains the inlet and oudet pipes as well as an intemal manifold tiiat delivers treated water to the outiet of the BayFilter'^'^ system. BAYSAVER TECHNOLOGIES, INC INLET PLATE MEDIA SPIRAL Kl MEDIA SPIRAL na INLET DRAINAGE MATERIAL r7-7\ aUTLET DRAINAGE XLJ-A MATERIAL i^H POLYMER SEAL I I OUTLET PIPE M AIR RELEASE VALVE TLOW CONTROL ORIFICE FILTER LEGS- 28,75' Stormwater mnoff enters the manhole or concrete stmcture via an inlet pipe and begins to fill the stmcture. An energv' dissipator at die vadt inlet slows the influent water and allows coarse sediments to settie within the structure. When the water surface elevation in the vault/manhole reaches operating level, water flows through die BFC driven by a hydrostatic head. Widiin the BFC, the water flows through a proprietary filter media and drains via a vertical pipe. The vertical drain is connected to the underdrain system which conveys filtered water to the outfall. During a typical storm event, the BayFilter''"'^ system has four cydes: 1. Vault fill and air release; 2. Uniform bed load hydrodynamic filtration; 3. Udtbrmbed;bhon Sltndor.: BAYSAVER TECHNOLOGIES, INC. 4. Siphon break and hydrodynamic backwash. A detailed depiction of the BFC operating sequence is given in Appendbc A. The Drain Down Cartridge Filter Each BayFilter'^'^ Stormwater Treatment System will include a number of standard BFCs and one or more drain down filter cartridges depending on site conditions. The drain down cartridge which has a flow capadty of 1 gpm, wUl allow the manhole/vault to empty after die siphon has broken and the standard BFCs are no longer operating. The drain down filter cartridge prevents die system from retaining standing water between storm events, thereby reducing the chance of mosquitoes or other disease vectors breeding within die system and preventing the system from becoming anaerobic during dry periods. This cartridge also uses the same media as die BFC and has a removal efficiency in excess of 90 percent. 20,50' — SOLID PLATE m MEDIA SPIRAL il 1^ MEDIA SPIRAL *2 f-T7[ INLET DRAINAGE iLjLi MATERIAL 1-7-71 DUTLET DRAINAGE MATERIAL I I DUTLET PIPE •• Pa.YMER SEAL DRAIN DOWN FLDW Figure 2: Drain Down Cartridge BAYSAVER TECHNOLOGIES, INC Performance Characteristics The BayFEter''"" has been extensively tested in die laboratory. This testing has been carried out using SIL-CO-SIL 106 as a sediment source. SIL-CO-SIL 106 is a silica product containing approximately 90% fine sediments {d^ = 23 microns), and is widely accepted as a sediment source for stormwater simulations by regulatory agencies such as die Washington State Department of Ecology (TAPE) program. New Jersey Department of Environmental Protection (TARP), as well as otiier leading agendes. The BFC needs only 28" of depth of water to begin full flow operation. Once the full flow operation has been achieved, the BFC will operate to a depth of 6" at which time the siphon will break and the system will backwash. At this point the only flow is from the drain down cartridge which wiU drain the vault to a depth below 1". Each BFC has a maximum nominal flow of 30 gpm. At this flow, each cartridge can treat 150 lbs of the total sediment load before maintenance. In addition, through the use of different size flow control orifice(s), the BFC flow is regulated. As the flow is lowered, the treated sediment load increases. For example, when the flow is lowered to 15 gpm, the cartridge is able to treat 300 lbs of the total sediment load before maintenance. A chart of the flows and total sediment loads can be found on Table 1. Flow Through (Foil Flow) Filtration Systems These systems are used in simations where a certain flow rate must be treated. Usually these are smaller projects where extended detention is either not feasible or not required. The treatment flow rate must be determined by the engineer. From this, the minimum number of BFCs is very simple to determine. Usually full flow systems require a large number of cartridges and because of this the maintenance cycles may be longer but more cosdy. The life of the cartridges can further be extended through the use of pretreatment with a BaySeparator'^'^. For these systems, use 30 gpm design flow per BFC for treated sediment loads up to 150 lbs. To use higher cartridge sediment loads of up to 300 lbs per BFC, see Table 1 for tiie appropriate flow-load relationships. A minimum head of 40" (for fiill flow) is required, as measured from die floor, to achieve die 30 gpm and die target sediment removal. Higher sediment loads can be achieved by induding pretreatment of die stormwater. Consult BaySaver Technologies, Inc. Engineering Department for more informarion. Post Extended Detention Filtration Systems These systems are used as a final measure of water treatment after it has been detained. In this configuration the BayFilter''"'^' system acts also as the co:--:olled v:i ±.vr'.y::: iot thc exceeded dece:-\:ion svstem. BAYSAVER TECHNOLOGIES, INC. Since these systems usually release and treat the water at relatively slow rates, the most common configuration for the BayFilter''^" system is to control the flow below 15 gpm, which accommodates 300 lbs per cartridge of treated sediment load. In many cases to accommodate the total annual sediment load of die system, in a post extended detention application, the BFC flow rate will be between 5 and 10 gpm. The sediment capacity will usually be the limiting factor in these applications. As can be seen from Table 1, the design flow rate is determined by the target amount of solids lo be removed. For example, if the designer's goal is to treat a cartridge sediment load of 150 lbs at 80% efficiency, die design flow rate would be approximately 30 gpm (0.067 CFS) per BFC. In anodier case, if the engineer is targeting a much heavier cartridge sediment load of 250 pounds; the design flow rate per BFC would then be 20 gpm (0.045 CFS). The different sediment removal/design flow rate relationships are achieved with minimum total heads of 40 inches as measured from die floor level, where the BFCs are instaUed (shown in Table 1). Consult BaySaver Technologies, Inc. Engineering Department for more information. At each design flow rate the BayFUter"^" cartridge wiU achieve a suspended sediment removal efficiency of over 80% at the rated flow rate. This 80% sediment removal efficiency' is based on laboratory testing using the SIL-CO-SIL 106 sediment gradation. The BayFUter'^^ cartridge has the capabUity to remove 50% ofthe total phosphoms load since most ofthe total phosphoms is typicaUy found in particulate form. Consult the BaySaver Technologies, Inc. Engineering Department for project specific information and detaUs regarding phosphorus removal requirements since they may var)' considerably from site-to-site. Table 1 Design Guidelines for BayFilter™ Cartridges BaySaver Technologies, Inc. Design Flow per BFC- gpm Nominal Treated Sediment Load for 80% Sediment Removal - Lbs Total System Head at Oesign Flow - Inches 30 150 40 23 200 40 20 250 40 15 300 40 (') Sediment with d5o= 23 microns Otiier kev operating parameters of BayFUter''"^ systems indude: ~<i''. BAYSAVER TECHNOLOGIES, INC. 2. Minimum head for the BFC to operate after fiUl flow is 6" (below the head the siphon wiU be broken); 3. Minimum water level for DDC operation is approxknately 1"; and 4. FuU flow head is at 40". BAYSAVER TECHNOLOGIES, INC. Design Guidelines fbr the BayFilter^'^ System Designing a BayFUter"^" system is done in four phases: (1) determine the treaunent train design; (2) locate the system on the site and incorporate it into the plans; (3) determine the number of cartridges necessary; and (4) select a system configuration. It is important to reaUze that the design process can be iterative until the desired design parameters are satisfied. Again, it is important to note that the BayFUter"^'"^ systems are designed offline. This section detaUs the design process and provides examples for each of the three steps. During the design process, the engineer must consider factors in addition to regulatory requirements. These indude: • Site specific constraints • Proposed system location " System configuration (flow through or extended detention) • Pretreatment • Effidency requirements • PoUutant loading (sediment load) • Treatment flow rates and hydrauUcs • Maintenance intervals BayFilter^'" Treatment Train Design On-line and Off-line Systems BayFUter''"^ systems are usuaUy designed to treat moderate to low flow rates. In the vast majority of appUcations, the peak design flow through the storm drain svstem wiU be si^rificantlv greater than the treatment design flow through BayFUter''"^. v.:-'•.; r,--..J, hvrais f:;u::arc' is reruired Eoi most Bavrilcer'"^' BAYSAVER TECHNOLOGIES, INC. instaUations. Therefore, BayFUter"^" systems are instaUed offline, utiUzing an external bypass to route high flows around the system. A schematic of an offline BayFUter'''^^ system is shown in Figure 3 below. The bypass stmcture diverts low flows to the BayFilter^M system and allows high flows to pass to a separate outfall. The bypass structure wUl feamre flow controls designed by an engineer to ensure that the required treatment flows are sent to the BayFUter^M. j]^^ ^^.Q effluent streams (the treated effluent from the BayFUter'"''^ and the high intensity bypass) may be combined into a single stream or discharged to separate outfaUs. These configurations typicaUy involve higher flow per cartridge, but reduced treated sediment load per cartridge. These configurations are, however, usuaUy Umited more by flow sediment capacity. Bypass Stcuccure Stormwater High Intensity Bypass BayFilter™ System Figure 3: OftTine BaySaver Technologies, Inc. System Filtered Stormwater In BayFUter'''" mstaUations sediment wUl accumulate in die vault as weU as in the filter cartridges. In offline instaUations high intensity flows are routed away from the vault minimizing the risk of resuspending this accumulated sediment. In onUne appUcations it is possible for high flows to mobiUze and release diis sediment. Pretreatment The BayFUter''"'^ system is designed to remove a minimum of 80% of suspended sediments and 50% of die total phosphorus load. If die antidpated sediment load is particulariy heavy or if there -wiU. be a significant oU load the system may require pretreatment. Pretreatment may also be required by local regulations. Pretreatment systems wUl remove a portion of die influent poUutant load. BaySaver Technologies, Inc. BaySeparator'^" system is an ideal hydrodynamic tlia' 'i'.TiO'.'Si Sf f.carrtbles frcim ?rarmvv-a:er mnoff BAYSAVER TECHNOLOGIES, INC.. Figure 4 shows a schematic of a typical BayFUter"^^' instaUation widi pretreatment. Note that the pretreatment stmcture is downstream from the bypass. The system wUl work as long as 28" of head is achieved to activate die cartridge flow and -wiU continue to work until it reaches the siphon break level (6"). Consult BaySaver Technologies, Inc. Engineering Department for verification based on your particular site conditions. By-Pass structure Stormwater High Intensity By-Pass Pretreatment BayFiiter'TM System • System System Filtered Stormwater Figure 4: Off line BayFilter''''^ System with Pretreatment Extended Detention Systems In some appUcations, BayFUter''"^ systems wUl be instaUed in conjunction widi extended detention systems. Extended detention systems attenuate peak flow rates within the storm drain system. In these cases, the BayFUter'^'^ is placed downstream firom an extended detention system, as shown in Figure 5. By-Pass Structure Stormwater High Intensity By-Pass Pretreatment System Extended Detention System BayFilter™ System Filtered Stormwater Oi'i.r.i P.i- :'r.:er™ Svsrerri v/i-h ExKaded Detendons BAYSAVER TECHNOLOGIES, INC. Systems widi smaUer drops can be designed as weU. The system wiU work as long as 28" of head is achieved to activate the cartridge flow and wUl continue to work until it reaches the siphon break level (6"). Consult BaySaver Technologies, Inc. Engineering Department for verification based on your particular site conditions. Preparing Site Pians forthe BayFiKer^'^ System Once the BayFUter''''^ system has been selected, the chosen system must be induded on the site plans. The hydrauUcs of the system must be considered as weU as the water surface elevation of the receiving water. FinaUy, the system must be placed in a suitable location on the site. Location The location of BayFUter'^^ on the site wUl be determined by several factors; maintenance access, the unit's footprint, available drop, avaUable depth, and the surface elevation of the receiving waters must aU be considered when selecting the system's location. The BayFUter'^'*' system must be instaUed in an area that is accessible to maintenance equipment. The annual maintenance of a BayFUter^^ system requires a vacuum tmck as weU as the removal and replacement of the filter cartridges. The manhole covers of the BayFUter''"^ must be placed in locations that can be easUy reached by such a vehide. The BayFUter''''^ should be placed in a location that minimizes its interference with other existing or planned underground utiUties. Selecting the Number of cartridges Each BayPUter"^^ system reUes on a coUection of individual cartridges to achieve the desired removal efficiency and it is important to correctiy determine the number of filter cartridges required. Too few cartridges wUl result in a system that does not meet the perfomiance specifications whUe too many cartridges wiU result in a system larger than necessary for the site. To accuratdy determine the number of cartridges required for a BayFUter''''*' instaUation, three factors must be considered: • The flow capacity of the system • Treated sediment load of the system ' Tun;-.SicdC'ii - 5]^ec;;I:v sI:i;no- requirement? (filter area-based) BAYSAVER TECHNOLOGIES, INC. Each of the above factors when evaluated wUl determine a minimum of cartridges required to address diat design parameter. Calculations for aU three factors need to be done to determine which design parameter is die limiting factor. In each case it wiU be the computation that results in the highest minimum number of cartridges, the one that wiU determine the cartridge count. In other words, whichever item requires the most cartridges to meet any one particular design parameter wiU determine the minimum number of cartridges required for the system. Required Data To ensure that the correct number of cartridges are specified for the BayFUter"""^ system, die designer must be aware of the local regdatory requirements for stormwater treatment. Depending on the jurisdiction in which the project site is located, the engineer may have to meet minimum treatment flow rates, treatment volumes or some other criteria such as filter bed area. Some jurisdictions specify a metiiodology for calculating a minimum treatment flow rate for a given site. Other jurisdictions may require extended detention upstream from the filtration system or have volume-based rather than flow-based requirements. Flow Capacity At many sites regulatory requirements wiU spedfy a minimum treatment flow rate (Q-TRT) diat must be passed through the stormwater treatment system. These regulatory requirements may also specify pretreatment or extended detention practices that need to be induded in the site design. Some jurisdictions specify that the stormwater filtration systems be designed on the basis of filter area foUowing prescribed methodologies. In some cases the BayFUter''''*^ system wiU have to be placed downstream from an extended detention faciUty or local regulations wiU spedfy a treatment volume rather dian a treatment flow rate. In these cases the minimum number of BFCs may not be determined using the treatment flow rate calculation. Instead, the minimum number of cartridges for tiiis system depends on the controUed discharge rate Qypj firom the upstream detention facUity or the filtration system. In most cases pretreatment can be provided by a hydrodynamic separator like the BaySaver Technologies, Inc. BaySeparator^" system. Regardless of the pretreatment design, the minimum number of BayFUter™ cartridges can be determined by dividing the treatment flow rate by 30 gpm (0.067 cfs) and rovmding up to the next whole number using Equation 1. This calculation provides the minimum number of BFCs that wUl be necessary to fiiUy treat the water quaUty flow from the site. This computation does not take into account the sediment load portion of the design, which needs to be performed as weU. The design flow per cartridge wiU liltimately be determined by the cartridge sediment load (Table 1). The step-by-step procedure is shown below. BAYSAVER TECHNOLOGIES, INC. 1. Determine the required treatment flow rate (STRT) based on locaUy approved mediodologies for the project site. This may involve the use of the Rational Method, TR-55 or anodier locaUy spedfied hydrologic model. If a locaUy approved metiiodology is not spedfied, BaySaver Technologies, Inc. recommends using one of these commonly accepted models. 2. Using the treatment flow rate, calcdate the minimum numbers of BayFUter^'^ cartridges required to treat that flow using Equation 1. Orer(c»* 448.8^ # Cartridges = ^ Equation 1 ^BFC The minimum number of BFCs is equal to the maximum treatment flow rate divided by rounded up to the next whole number. In most cases,^gpcwUl be 30 gpm (0.067 cfs) per cartridge. Sediment Lx>ad Capacity Once die minimum number of BFCs required to treat the flow is known, the engineer must ensure that the number of BFCs spedfied wiU be capable of handUng the sediment load from the site. BayFUter''''^ systems are typicaUy designed around a maintenance cyde. It is important to note that the number of BFCs required to treat the antidpated total system sediment load is a minimum number. For any site, it is necessary to calculate the minimum number of BFCs required to treat both the peak flow rate and the total system sediment load (as discussed in this section). The number of BFCs required for the site is the^ateroi the calculated numbers. To ensure that the BayFUter'^'"** wUl function acceptably with annual maintenance, it is necessary to calculate the incoming annual sediment load from the site. 1. Calculate the annual treated runoff volume according to Equation 2. In Equation 3, T^^T is the annual treated runoff volume, P is the VjRj(jt'^\=P* A*C* * '^'i'^^^fi ^ 0/^ Capture Equation 2 12m acre average annual predpitation (in inches), A is the area of the site (in acres), f is the runoff coefficient oftiie site (c is dimensionless), and % Capture is the fraction of the total mnoff that is treated by the stormwater quaUty system. If % Capture is not odierwise spedfied, a default value of 0.90 can be used. BAYSAVER TECHNOLOGIES, INC. 2. Using the annual treated mnoff volume, calculate the antidpated total system sediment load to BayFUter''"'^ according to Equation 3. In Equation 3, L is the mass of sediment that BayFUter''"" is exposed to annuaUy (in pounds), Vj^j is the annual treated mnoff volume as calculated in step 1 (in ft'), and TJi"^- is the influent concentration of TSS in the mnoff (in mg/L). The influent TSS concentration (TU^^,) r_T/ *'rcc *283I^ kg ^l.llbs ^-'^TRT •''^'^w „3 TTe ~~; Equations ft 10 mg kg depends greatiy on the site and the surrounding land use. In the absence of readUy avaUable data, BaySaver Technologies, Inc. recommends using a minimum event mean concentration (EMC) TSS value of 60 mg/1. The impact of the on the filter cartridge wUl also be less if the filtration system is preceded by pretreatment. In these cases, the influent TSS to the BayFUter'^" system need to be reduced to reflect pretreatment sediment removal. The BaySaver Technologies' Engineering Department can assist with tiiese calculations. 3. Once the total annual system sediment load (L) is calculated, the engineer must ensure that the number of cartridges spedfied wUl be able to remove that sediment load at the spedfied design flow rate. Divide the total system sediment load L by the capacity of each BFC and note the assodated BFC flowrate. Round up to the next whole number to get the minimum number of BFCs required to treat this sediment load at the required flow rate per BFC. Jurisdictional Rlter Requirements This procedure is used when the filtration area is defined by regulations. To determine the number of cartridges based on a filtration area requirement dictated by regdations the foUowing steps are foUowed: 1. Determine the required total minimum filtration area Af in ft' based on the locaUy mandated methodology for the project site. Next determine the number of Drain Down Cartridges required and their area contribution based 29 ft' per Drain Down Cartridge pDC) and one (1) DDC per 1,300 ft'of filter area requirement. Round up to the next whole number to obtain the number of DDCs. # DDCs = ^l^JLl Equation 4 BAYSAVER TECHNOLOGIES, INC. 2. Calculate the required fdter area from the BFCs by subtracting the DDC area from the total area fdtration area. Determine the minimum number of BFCs needed by dividing the required are by 43 ft^/BFC. Round up to the next whole number to obtain the number of BFCs. BFC Area = Af{ft^)-^§DDCs*^^^ Equation 5 BFC # of BFCs = BFC Area * r- Equation 6 Summaiy After the above calculations are complete the limiting factor wiU be the largest number of cartridges that these three (3) calcuiations determined (flow, sediment load, and jurisdictional/area, if appUcable). These results then define the final number of BayFUter''''^ cartridges required for the system. Examples of typical calculations are provided below. Example 1 Flow Capacity Calculations Determines the minimum nuinber of BFCs required to treat the design flow rate. Step I: Determine the required treatment flow rate (QTRJ) based on locally approved methodologies forthe project site. QTRT= 2.38 cfs Step 2: Using QTKT^ calculate the minimum number of BFCs required using Equation 1. 2.38c/j * # of Cartridges = 448.8g/?w cfs 30 gpm BFC # of Cartridges = 35.6 cartridges Round up to the nearest whole number. The minimum number of BayFilter^Mcartridges required to treat the design treatment flow from this site is 36 cartridges. Resuh: 36 I livriiter"^*' Cart.-l-'v.es p';;-; two (2) Drain Down Cartridses 15 BAYSAVER TECHNOLOGIES, INC. Example!: Determine the minimum number of BFCs required for a project site based on a controlled rate Step 1: Determine the controlled release rate (CCR) of the system given a storage volume based on a locally approved methodology VTRT= 26,572 ft' volume that need treatment VTRT= 198,759 gallons volume that need treatment Draindown Time = 40 hours CCR = 198, 759 gallons / (40 hrs * 60 min/hr) CCR= 82.8 gpm Step 2: Determine the minimum number of BFCs required based on the CCR and a 30 gpm/BFC flow rate # of BFCs required = 82.8 gpm / (30 gpm/BFC) # of BFCs required = 2.76 BFCs Round up to the next whole number. The minimum number of BFCs required is then 3 Result = 3 BFCs This system will consist of 3 BFCs minimum and 1 DDC BAYSAVER TECHNOLOGIES, INC. Example 3: Sediment Load Calculations Determines the minimum number of BFCs required to handle the anticipated annual sediment load from the project site. Step 1: Calculate the annual treatment volume (^^7-) according to Equation 3. F= 43.8 inches per year A = 3.42 acres c = 0.85 % Capture = 0.90 Vr,r = (43.8"X3.42.cr^.X0.85)[|||iH^j(0.90) VfRr= 415,976 ft' per year Step 2: Using VTRT, calculate the anticipated total sediment load to BayFilter™ using Equation 4. VTRT= 415,976 ft' TSSm = 80 mg/1 L = 2,072 pounds total annual sediment load Step 3: For example, if the cartridge sediment load per BFC is 150 lbs/cartridge (see Table 1, BFC flow is 30 gpm), divide the annual sediment load L by 150 lbs/cartridge and round up to the next whole number. # of Cartridges = 13.8 cartridges Result: 14 BayFilter™ Cartridges plus one (1) Drain Down Cartridge *The % capture is the fraction of the total runoff tiiat is treated by die stormwater quaUty system. BAYSAVER TECHNOLOGIES, INC. Example 4: Filter Bed Area Calculations Determines the minimum number of BFCs required for a project site based on a regulatory driven filtration area requirement. Step I: Detennine the required total minimum filtration area based on the locally mandated methodology for the project site Af = 1,643 ft- Step 2: Determine the number of Drain Down Cartridges required and their area contribution based on 43 ft* per BayFilter™ cartridge (BFC) and 29 ft2 per Drain Down Cartridge (DDC) and one (1) DDC per 1,300 ft" of filter area requirement # of DDC required = 1.26 Round up to the next whole number. Number of DDCs required is then two(2) Result: 2 DDCs Filtration area provided by the DDC = 58ft' Step 3: Determine the number of BFCs required based on the next filtration area requirements by subtracting the DDC area from total area filtration area Total Filtration Area Required Af = 1,643 ft' DDC Filtration Area = 58 ft' BFC Filtration Area Requirement = 1,585 ft" Step 4: Determine the minimum number of BFCs based on the BFC Filtration Area Requirement #of BFCs required = 36.9 BayFilter™ Cartridges Round up to the next whole number. The minimum number of BFCs required is then 37 Result: 37 BFCs This system will consist of 37 BFCs and 2 DDCs It is important to note that the BFC and DDC count is the minimum requirement and other factors miviht make the above figures larger, therefore all designs constraints need to be ir.*:- ^i;:'.: arri'- c at f,na! design cartridge count. Contact BaySaver Technologies Inc. : r. -ec-::. 0 jrvir:-?-: \ X'AZ'^S)J1%Z fbr dssian a$i!stance. BAYSAVER TECHNOLOGIES, INC BayFilter^*^ System Configuration The BayFUter'^'^ Stormwater Treatment Systems are avaUable in three different configurations: • Manhole filter • Precast vault filter " Cast-in-place vault filter This section detaUs the capabUities of each of these configurations, and provides guidance for selecting the most suitable configuration for a site. Manhole BayFittefT" The manhole configuration system avaUable. It is usuaUy ranging from 60 gpm (0.13 manhole. FUter cartridges, BaySaver Technologies, Inc. flow capadties are shown determined on a site spedfic the engineer. BayFUter'''" system is die most economical BayFUter''"" used for smaU drainage areas, and has a treatment capacity cfs) for a 60" manhole to 330 gpm (0.74 cfs) for a 120" underdrain components, and manholes are suppUed by as a complete system. Manhole BayFUter''"" sizes and in Table 2. The minimum system drop is typicaUy basis by BaySaver Technologies, Inc. in conjunction with BayFUterT" Manhole Maximum Maximum Model Size Number of Treatment Flow (inches) BFCs gpm (cfs) MHF-60-2 60 2 60 (0.13) MHF-72-3 72 3 90 (0.20) MHF-84-4 84 4 120 (0.27) MHF-96-6 96 6 180 (0.40) MHF-120-11 120 11 330 (0.74) Table 2: Manhole BayFilter™ Capacities A 72" Manhole BayFUter^" Modd MHF-72-3 is shown in Figure 6. The 72" Manhole BayFUter'''" contains 3 BFCs for a maximum treatment flow of 90 gpm (0.20 cfs), as weU as a single drain down filter cartridge (die lower left cartridge in Figure 11, labeled DDCl) as described in Chapter 2 of this manual. The drain down filter, which has a flow rate of 1 gpm (0.002 cfs), aUows the manhole to be dewatered between storms after the siphon is broken and the standard BFCs stop filtering stormwater. The inlet and oudet pipes of the 72" Manhole BayFUter''"" are each 4" P"V"C; these pipes are connected to the manhole usiag watertight boots to prevent leakage when the filter is operating. In the Manhole BayFUter''"", the P'VC oudet pipe is directiy connected to the outiet manifold. Engmeering drawings of each available Manhole BayFUter'''" can be i:.>\^v•d m Ar^oertdix C. BAYSAVER TECHNOLOGIES, INC, 4' DUTLET 072'- ENERGY DISSIPATDR/- LEVEL SPREADER 6' INLET MINIMUM MSCWTON BUt^fPS NOTES: 9 BAYSAVER &ATC: tO/U/Oi SCALE: ivo >o te-ix FIGURE: 6 MANHOLE BAYFILTER MODEL MHP-72-3 The Manhole BayFUter'''" includes an energy Dissipator/Level Spreader at die inlet to die stmcture. This component spreads the influent water evenly through the stmcture and prevents high flows from impacting die BFCs direcdy. Manhole BayFUter'''" systems have a smaU footprint, and can be fit into site plans easUy witiiout interfering widi otiier underground utiUties. Manhole BayFUter''"" systems are ideal for appUcations downstream from extended detention stmctures. Please consult widi tiie BaySaver Technologies, Inc. Engineering Department for more detaUs. Access to the Manhole BayFUter''^" for inspection or maintenance is achieved chroviyh f. n-irinuxn 30" frame and co\-er. In each Manhole BayFUter'"^' system, the Lteriance \vorker can simd on tb tioor or die m^annoi; BAYSAVER TECHNOLOGIES, INC, whUe instaUing or removing the cartridges. Please refer to Appendix C for engineering drawings showing the avaUable Manhole BayFUter"'"" configurations. Precast Vautt BayFilter^" When more BFCs are required. Precast Vadt BayFUter''"" systems may be vised on larger sites or sites with more impervious area. The Precast 'Vadt BayFUter''"" system is larger than the Manhole BayFUter"""". Constmcted within a precast concrete vault, it has a treatment capacity ranging from 240 gpm (0.53 cfs) in an 8' x 10' vault to 2,010 gpm (4.48 cfs) in a 10' x 48' vault. Shodd precast vadts of the dimensions oudined in Table 3 not be available locaUy, these stmctures can be cast in place. Table 3 shows the avaUable Precast Vault BayFUter"""" systems, along with the maximum number of filter cartridges and treatment capadties. The mimmum system drop is typicaUy addressed on a site spedfic basis by BaySaver Technologies, Inc. in conjunction with an engineer. BayFilterT^*^ Modd Vadt Size (fir x ft) Maximum Number of BFCs Maximum Treatment Flow gpm (cfs) PVF-10-8-8 8' X 10' 8 240 (0.53) PVF-10-16-20 10' X 16' 20 600 (1.34) PVF-10-24-31 10' X 24' 31 960 (2.14) PVF-10-32-43 10'x32' 43 1290 (2.87) P\T-10-40-55 10'x40' 55 1650(3.68) PVF-10-48-66 10' X 48' 66 2010(4.48) Table 3: Precast Vault BayFilter™ Capacities Figure 7 shows the layout of a PVF-10-8-8, an 8' x 10' Precast Vadt BayFUter'''" system. The system comprises dght standard BFCs and a single drain down filter. like the Manhole BayFUter''"", die Precast Vadt BayFUter''"" also indudes an energy dissipator/level spreader to evenly distribute die water through the stmcture. UnUke die Manhole BayFUter"'"", the outiet manifold in die Precast Vadt BayFUter''"" does not connect directiy to the oudet pipe. Instead, each of die six underdrain Unes enters an HDPE outiet manifold and discharges filtered water to an oudet chamber. The outiet pipe drains this oudet chamber. ai BAYSAVER TECHNOLOGIES, INC, lUTLET HEADER 96' ENERGY DISSIPATDR/ LEVEL SPREADER INLET DCSCWPnOW iowt HPW fWTCt BAYSAVER OeaOlES; TCP SCAUi HTi owe KO ir-zot FIGURE: 7 VAULT BAYFILTER MOOEL PVF-10-8-8 Like the Manhole BayFUter"""", access to the Precast Vault BayFUter''"" is provided through the hinged access hatch. The Precast Vault BayFUter''^" is constmcted in 10' x 8' sections. Each vadt has at least one access hatch. The BFCs and outiet manifolds are arranged to aUow maintenance personnel to stand on the concrete floor whUe working inside the stmcture. The BayFUter"""" cartridges and underdrain manifold components are suppUed by BaySaver Technologies, Inc. together with the precast vadts. Please refer to Appendix C for a complete set of Precast Vadt BayFUter''"" configurations. BAYSAVER TECHNOLOGIES, INC. Cast-in-place BayFilter'" For sites requiring more than 66 BFCs or for projects on which a large Precast Vadt BayFUter"'"" is not feasible, BaySaver Technologies, Inc. can supply custom- designed BayFUter^" systems. These custom systems utUize a cast in place vadt or other system, and can be designed around specific site constraints. High flow rates, shaUow instaUations, very flat sites, Umited footprints, and other design considerations can be addressed with a cast in place system. For more information on custom BayFUter"""" designs, please contact BaySaver Technologies, Inc. directiy. BAYSAVER TECHNOLOGIES, N C . installation of tlie BayFilter^'^ System BayFUter"'^" systems are instaUed along with the storm drain. Instaliation procedures vary depending on the configuration of the BayFUter^"^" system. InstaUation instmctions for Manhole BayFUter^" systems and Precast Vadt BayFUter"'"" Systems are contained in this section. Custom BayFUter'''" systems may have particular installation issues that wUl be addressed during the design. Installation instmction for the custom BayFUter''"" wUl be induded with the custom design documents. BAYSAVER TECHNOLOGIES, INC. Installation of a Manhole BayFilter -TIVI 1. Contact utiUty locator to mark any nearby underground utiHties and make sure it is safe to excavate. 2. Reference the site plan and stake out the location of the BayFUter^" manhole. 3. Excavate the hole, providing any sheeting and shoring necessary to comply with aU federal, state and local safety regdations. 4. Level the subgrade to the proper elevation. Verify the elevation against the manhole dimensions, the invert elevations, and the site plans. Adjust the base aggregate, if necessary. 5. Have the soU bearing capadty verified by a Ucensed engineer for the required load bearing capadty. On soUd subgrade, set the base of the BayFUter"'"" manhole. 6. Check the level and elevation of the base unit to ensure it is correct before adding any riser sections. 7. Add watertight seal (either mastic rope or mbber gasket) to the base unit of the BayFUter^" manhole. Set riser section(s) on the base unit. 8. InstaU die PVC watertight outiet manifold within the BayFUter"''" manhole. 9. InstaU the inlet pipe to the BayFUter''"" manhole. 10. InstaU the energy dissipator/level spreader at the system inlet location. 11. After the site is stabilized, remove any accumdated sediment or debris from the manhole and instaU the BayFUter"'" cartridges. BAYSAVER TECHNOLOGIES, INC, •TM Installation of Precast Vault BayFiKer 1. Contact UtUity locator to mark any nearby underground utUities and make sure it is safe to excavate. 2. Reference the site plan and stake out die location of the BayFUter''"" vadt. 3. Excavate the hole, providing any sheeting and shoring necessary to comply with aU federal, state and local safety regdations. 4. Level the subgrade to the proper elevation. Verify the elevation against the manhole dimensions, the invert elevations, and the site plans. Adjust the base aggregate, if necessary. 5. Have the soU bearing capacity verified by a Ucensed engineer for the required load bearing capadty. On soUd subgrade, set the first section of the BayFUter'''" precast vadt. 6. Check the level and elevation of the first section to ensure it is correct before adding any riser sections. 7. If additiond section(s) are required, add a watertight seal to the first section of tiie BayFUter'''" vadt. Set additiond section(s) of the vadt, adding a watertight sed to each joint. 8. InstaU the PVC outiet manifold and oudet chamber system. 9. InstaU die PVC oudet pipe in BayFUter''"" vadt. 10. InstaU the inlet pipe to the BayFUter"'"" vadt. 11. InstaU the energy dissipator/level spreader at the idet pipe. 12. After die site is stabUized, remove any accumulated sediment or debris from the vadt and instaU the BayFUter"'^" cartridges. BAYSAVER TECHNOLOGIES, INC. Maintenance of the BayFilter^'^ System The BayFUter"'"" system requires periodic maintenance to continue operating at the design effidency. The maintenance process comprises the removd and replacement of each BayFUter""^" cartridge and the deaning of the vadt or manhole with a vacuum tmck. BayFUter^" maintenance shodd be performed by a BaySaver Technologies, Inc. certified maintenance contractor. The maintenance cyde of the BayFUter"""" system wiU be driven mostiy by the actud soUds load on the filter. The system shodd be periodicaUy modtored to be certain it is operating correctiy. Since stormwater soUds loads can be variable, it is possible that the maintenance cyde codd be more or less than the projected duration. "When a BayFUter"''" system is first instaUed, it is recommended that it be inspected every six (6) months. "SVhen the filter system exhibits flows below design levels the system shodd be maintained. FUter cartridge replacement shodd dso be considered when sediment levels are at or above the levd of the 4 coUector pipes to the madfold. Please contact the BaySaver Technologies Inc. Engiaeering Department for maintenance cycle estimations or assistance at 1.800.229.7283. BAYSAVER TECHNOLOGIES, INC. Maintenance Procedures 1. Remove the manhole covers and open aU access hatches. 2. Before entering the system make sure the air is safe per OSHA Standards or use a breathing apparatus. Use low Oj, high CO, or otiier appUcable warning devices per regulatory requirements. 3. Using a vacuum tmck remove any Uquid and sedunents that can be removed prior to entry. 4. Using a smaU Uft or the boom of the vacuum tmck, remove the used cartridges by Ufting them out. 5. Any cartridges that cannot be readUy Ufted can be sUd dong the floor to a location where they can be Ufted via a boom Uft. 6. When aU cartridges are removed, remove the bdance of the soUds and water; then loosen the staidess clamps on the Fernco couplings for the manifold and remove the drain pipes as weU. Carefdly cap the madfold and the Femco's and rinse the floor removing the balance of the coUected soUds. 7. Clean the mamfold pipes, inspect, and reinstaU. 8. InstaU the exchange cartridges and close aU covers. 9. The used cartridges must be sent back to BaySaver Technologies, Inc. for exchange/recycling and credit on undamaged vmits. BAYSAVER TECHNOLOGIES, INC. BayFiKer^'^ System Costs and Availability BayFUter"""" systems are avaUable throughout the United States from BaySaver Technologies, Inc. or from an authorized representative. Materid, instaUation, and maintenance costs can vary significantiy with location. For BayFUter''"" pricing in your area, please contact BaySaver Technologies, Inc. at 1-800-229-7283 (800-BAYSAVE) or an authorized representative direcdy. BayFUter""^" cartridges and oudet components can be shipped anywhere in the continentd United States. Manholes and precast vadts are dso suppUed by BaySaver Technologies, Inc. as part of a complete stormwater filtration system. BAYSAVER TECHNOLOGIES, INC. Appencfx BayFilter'"' Detailed Operating Sequence The cycle operation of a BayFUter""^" is as foUows: A. Vadt FUl and Air Release: As water fUls the BayFilter"""" stormwater fUtration system vadt, it enters through an inlet pipe to an energy dissipator/level spreader. This aUows for even flow into the vadt and limits any high velocity scouring of the sediment. As the water fiUs the vadt, influent water passes through the inlet plate. As the level rises in the vault, air from inside the BFC is exhausted via an air release vdve. This operation is critical for the proper functioning of the siphon, which drives the BayFUter^" during periods of low water level in the vault. (Refer to Figure A-l for detaUs on this operation). .10 BAYSAVER TECHNOLOGIES, INC. Figure A-l: Vault fill operation and release BAYSAVER TECHNOLOGIES, INC. B. FUtration: As water enters the idet drainage spiral, which is one continuous spiral, the air is exhausted. "Water then flows horizontaUy through the engineered media. Next it flows to the oudet drainage spiral, which is also one single spiral of oudet material. The fUtered water then flows verticaUy to the outiet chamber located on the inside top of the fUter. FinaUy, the fUtered water flows to the center oudet drain and out through the oudet manifold below the inlet plate. (Figure A-2) HI INLET PLATE m MEDIA SPIRAL ttl H MEDIA SPIRAL tta fTTI INLET DRAWAGE SCJLi MATERIAL (TTH OUTLET DRAINAGE Y / A MATERIAL m PDLYMER SEAL I I OUTLET PIPE AtR RELEASE VALVE FLGV CONTROL ORIFICE FEED WATER FLOV Figure A-2: Normal filter operation :i2 BAYSAVER TECHNOLOGIES, INC. C. Siphon FUtration: After the water level in the vadt faUs below the top of the fUter, a siphon is estabUshed and water wfll continue to flow (Figure A-3) until the siphon is broken. During siphon flow the level in the vault wiU decrease until it reaches the base of the BFC; air enters the fUter, breaks the siphon, fUtration flow stops, and the hydrodynamic backwash begins. Figure A-3: Siphon filtration 23 BAYSAVER TECHNOLOGIES, INC. D. "When air enters the filter, the siphon breaks (Figure A-4), and a gravity-driven backwash occurs with aU of the water flowing from the oudet chamber backwards through the fdter (Figure A-5). This backwash has the effect of dislodging particles captured in the fUtration layers and re-estabUshing porosity. Dislodged particles are transported by the backwash and accumdate on the vadt floor. Figiiie A-4-: Siphon Brsak BAYSAVER TECHNOLOGIES, INC, INLET PLATE MEDIA SPIRAL ttl MEDIA SPIRAL tt2 f Xyi INLET DRAINAGE VL£U MATERIAL r7~7\ OUTLET DRAINAGE tlZJ MATERIAL POLYMER SEAL OUTLET PIPE AIR RELEASE VALVE FLDW CONTROL ORIFICE -FEED WATER FLDW FILTERED WATER FLOW -WATER FLOW THROUGH MEDIA Fiei'.re A.-5: K'.'droiirr.an-ic Baciro-ash BAYSAVER TECHNOLOGIES, INC. Appencfx General Checklist fbr Designing a BayFilter'''^ System This Ust is pro\ided for generd informationd purposes. BaySaver Technologies wUl work closely with the engineer to design the BayFUter''"" System and produce a complete design package. For assistance, please contact BaySaver Technologies Inc. at 1.800.229.7283. 1) Understand the constraints of the project: a) Govermng Regdations on Configuration: (1) Flow or volume to be treated (2) Treatment efficiency b) Site Specific Limitations: (1) AvaUable footprint (2) AvaUable head (3) PoUutants and Loads (4) Other specific site issues 2) Determine the best configuration based on the above: a) WUl there be pretreatment? b) Is Extended Detention possible or avaUable? c) What configurations are avaUable? d) What is the minimum maintenance cycle? 3) Determine the minimum number of cartridges: a) The system is then configured based on the determining the minimum number of cartridges on the foUowing parameters. The largest minimum number of cartridges associated with an appUcable parameter wiU be the minimum svstem configuration. 3S BAYSAVER TECHNOLOGIES, INC. b.) The parameters to be computed are: (1) FUter Area(some jurisdictions evduate based on this) (2) FuU Flow Rate(if this configuration appUes) (3) Treated Sediment load (always important to determine maintenance cycles) (4) Treated Sediment load w/ Pretreatment (increases treatable sed. load) (5) ControUed Flow Rate(if this appUes) 4) In order to compute the above items the foUowing must be known about the site and the drainage area to the FUtration system: (1) Site Area: (a) Impervious Area (b) Pervious Area (2) Treatment Flow Rate(if appUcable) (3) Annual Sediment load (or) Annud RainfaU to be treated (and) Runoff coefficient for Impentious/Pervious Area (4) Extended Detention volume(if appUcable) (5) Extended Detention Release Rate (6) AvaUable head and/or elevation change avaUable for the system including pretreatment and extended Detention With this data the minimum number of BFC cartridges can be determined for a particular site. 37 BAYSAVER TECHNOLOGIES, INC Advantages and Disadvantages of System Configurations Advantages Dis advantages Full Flow Configuration Easiest to configure Costly configuration Full flow treatment Smallest footprint Most expensive maintenance and life cycle cost Full flow treatment with BaySeparator^" pretreatment Simple to configure slighdy larger footprint than without pretreatment, but still a small footprint Extended maintenance cycle The most costly configuration at installation, but lower life cycle costs than the system without pretreatment Reduced life cycle costs than above Fewer cartridges and lower cost, even when the cost of the extended detention is accounted for Treatment after Extended Detention without BaySeparator''^" pretreatment Extended detention usually significandy increases the foot print of the system Lower flow rates of each cartridge thereby increasing the sediment capacity per cartridge and the system Usually requires additional available head(system drop) Controlled flow Configurations Because of the increase in head in the system more head is available to enhance the filter cartridge operation Lower maintenance cost than the above options Lowest cost system, although the initial cost is slighdy higher than without pretreatment, the life cycle costs are the lowest due to the increased maintenance interval because of the pretreatment systein Treatment after Extended Detention and Pretreatment Lower flow rates of each cartridge thereby increasing the sediment capacity per cartridge and the system Pretreatment adds additional footprint to the system making it the largest footprint of the BaySaver Technologies, Inc. treatment opdons(although soli less than most other systems) Because of the increase in head in the system more head is available to enhance the filter cartridge operation More cosdy than without pretreatment at the time of installation but this is quickly offset by the lifecycle cost reduction Lowest maintenance cost rhan the I all ofth? above opdon.5 33 BAYSAVER TECHNOLOGIES, INC, Note: This table is provided as a generd reference ody, since site specific conditions and other requirements or constraints may dictate a site spedfic design approach. 39 BAYSAVER TECHNOLOGIES, INC, System Drawings 40 A" DUTLET 060''- ENERGY DISSIPATDR/ LEVEL SPREADER G" INLET MINIMUM HEV DESCRIPTION DATE APPR NOTES: BAYSAVER TECHNOLOGIES. INC. WWW.BA YSA VCR.COM DESIGNED: TEP DRAWNi AJV CHECKED: AJV DATE: 11/6/06 SCALE: N.T.S. DWG m' BF-lOl MANHOLE BAYFILTER MODEL MHF-60-2 A" OUTLET 072^'- ENERGY DISSIPATDR/- LEVEL SPREADER 6" INLET MINIMUM KEV DESCRIPTION DATE APPR NOTES: BAYSAVER TECHNOLOGIES. INC. WWW.BAYSAV6R.COM MANHOLE BAYFILTER DESIGNED: TEP DATE: 11/6/06 MODEL MHF-72-3 DRAWNi AJV SCALE: N.T.S. CHECKED: AJW DWG NO" BF-102 084 A" OUTLET ENERGY DISSIPATDR/- LEVEL SPREADER 6* INLET MINIMUM REV DESCRIPTION DATE APPR NOTES: BAYSAVER ^PRS TECHNOLOGIES. INC. •^M^ WWW.BAYSAVER.COM MANHOLE BAYFILTER MODEL MHF-84-4 NOTES: BAYSAVER ^PRS TECHNOLOGIES. INC. •^M^ WWW.BAYSAVER.COM MANHOLE BAYFILTER MODEL MHF-84-4 NOTES: DESIGNED: TEP DATE: 11/6/06 MANHOLE BAYFILTER MODEL MHF-84-4 NOTES: DRAWNi AJW SCALE: N.T.S. MANHOLE BAYFILTER MODEL MHF-84-4 NOTES: CHECKED: AJV DWG NO' BF-103 MANHOLE BAYFILTER MODEL MHF-84-4 096'- 4' OUTLET ENERGY DISSIPATDR/- LEVEL SPREADER 6' INLET MINIMUM REV OESCRIPTION DATE APPR NOTES: BAYSAVER ® TECHNOLOOIES. INC. b,UI41»MliHM.,.*'AIUWlUIM« WWW.BAYSAVER.COM MANHOLE BAYFILTER DESIGNED: TEP DATE: 11/6/06 MODEL MHF-96-6 DRAWNI AJW SCALE: N.T.S. CHECKED: AJW DWG NOl BF-IO-I 6' OUTLET 0120 ENERGY DISSIPATDR/- LEVEL SPREADER 6' INLET MINIMUM liEV DESCRIPTION OATE APPR NOTES: BAYSAVER TECHNOLOGIES. INC. WWW.BAySAVER.COM MANHOLE BAYFILTER DESIGNED: TEP DATE: 11/6/06 MODEL MHF-120-11 DRAWNI AJW SCALE: N.T.S. CHECKED: AJW DWG ND. BF-105 ENERGY DISSIPATOR/ LEVEL SPREADER INLET UTLET HEADER REV DESCRIPTION DATE APPR NOTES: BAYSAVER TECHNOLOGIES. INC. WWW.BAYSAVHR.COM VAULT BAYFILTER DESIGNED: TEP DATE: ia/a7/06 MODEL PVF-10-8-8 DRAWNi AJW SCALE: N.T.S. CHECKED: AJW DWG NOl BF-201 ENERGY DISSIPATDR/ LEVEL SPREADER UTLET HEADER 192' INLET REV DESCRIPTION OATE APPR NOTES: BAYSAVER TECHNOLOOIES. INC. (MMtfWMflMMWAIUlMllUinM WWW.BAYSAVIiR.COM DESIGNED: TEP DRAWNi AJW CHECKED: AJW DATE: 12/27/06 SCALE: N.T.S. DWG NQi BF-202 VAULT BAYFILTER MODEL PVF-10-16-20 13' DUTLET 31 DD ENERGY DISSIPATDR/- LEVEL SPREADER UTLET HEADER REV OESCRIPTION DATE APPR NOTES: BAYSAVER TECHNOLOGIES. INC. »,U.,UMt.JliaWlV.iiJIMUlM,l WWW.BAYSAVER.COM DESIGNED: TEP DRAWNi AJW CHECKED: AJW DATE: 12/27/06 SCALE: N.T.S. DWG NQi BF-203 VAULT BAYFILTER MODEL PVF-10-24-31 UTLET HEADER ENERGY DISSIPATDR/-^ L-<=J LEVEL SPREADER INLET DESCRIPTION DATE APPR NOTES: BAYSAVER TEOINOLOOIES. INC. WWW.BAYSAVER.COM DESIGNED: TEP DRAWNI AJW CHECKED: AJW OATE: 12/27/06 SCALE: N.T.S. DWG NQI BF-204 VAULT BAYFILTER MODEL PVF-10-32-43 TLET HEADER ATOR/-/ I—«=J ENERGY DISSIPATDR/-' LEVEL SPREADER INLET REV DESCRI PTK)N DATE APPR NOTES: W0 BAYSAVER TECHNOLOGIES. INC. WWW.BAYSAVER.COM DESIGNED: TEP DRAWN. AJW CHECKED: AJW OATE: 12/27/06 SCALE: N.T.S. DWG NO' BF-205 VAULT BAYFILTER MODEL PVF-10-40-55 120' IS' OUTLET i a •I IR/-' L= h UTLET HEAKR ENERGY DISSIPATOR/- LEVEL SPREADER INLET REV DESCRIPTION DATE APPR NOTES: BAYSAVER TEaiNOLOGIES. INC. WWW.BAYSAVER.COM DESIGNED: DRAWNI AJW CHECKED: AJW OATE: 12/27/06 SCALE: N.T.S. DWG NQI BF-206 VAULT BAYFILTER MODEL PVF-10-48-66 Vegetated Swale TC-30 Design Considerations • Tributary Area • A-ea Required • Slope • Water Availability Description Vegetated swales are open, shaEow channels with vegetation covering the side slopes and bottom that coUect and slowly convey runoff flow to downstream discharge points. They are designed to treat runoff through filtering by liie vegetation in the channel, filtering through a subsoil matrix, and/or infiltration into the underlying soils. Swales can be natural or manmade. They trap particulate poUutants (suspended soHds and trace metals), promote infiltration, and reduce the flow velocity of stormwater runoff. Vegetated swales can serve as part of a stormwater drainage system and can replace curbs, gutters and storm sewer systems. California Experience Caltrans constructed and monitored six vegetated swales in southem Califorma. These swales were generaUy effective in reducing the volume and mass of poUutants in runoff. Even in the areas where the annual rainfaU was only about lO inches/yr, the vegetation did not require additional irrigation. One factor that strongly affected peiformance was the presence of large numbers of gophers at most of the sites. The gophers created eartiien moimds, destroyed vegetation, and generally reduced the effectiveness of tiie controls for TSS reduction. Advantages • If properly designed, vegetated, and operated, swales can serve as an aesliietic, potentiaUy inexpensive urban development or roadway drainage conveyance measure with significant coUateral water quaUty benefits. Targeted Constituents EI Sediment A 0 Nutrients • 0 Trash • EI Metals • 0 Bacteria • 0 Ql and Grease A 0 Organics A Legend (Removal Effectiveness) • Low • High A Medium urox-;iAao anvATBt January 2003 Califomia Stormwater BMP Handbook INew Development and Redevelopment www. cabmphandbooks. com 1 of 13 TC-30 Vegetated Swaie • Roadside ditches should be regarded as significant potential swale/buffer strip sites and should be utiUzed for this purpose whenever possible. Limitations • Can be difficult to avoid channeHzation. • May not be appropriate for industrial sites or locations where spUls may occur • Grassed swales cannot treat a very large drainage area. Large areas may be divided and treated using multiple swales. • A thick vegetative cover is needed for fhese practices to function properly. • They are impractical in areas vrith steep topography. • They are not effective and may even erode when flow velocities are high, if the grass cover is not properly maintained. • In some places, their use is restricted by law: many local municipaUties require curb and gutter systems in residential areas. • Swales are mores susceptible to faUure if not properly maintained than other treatment BMPs. Design and Sizing Guidelines • Flow rate based design determined by local requirements or sized so that 85% of fhe annual runoff volume is discharged at less than the design rainfaU intensity. • Swale should be designed so that the water level does not exceed 2/3rds the height of the grass or 4 inches, which ever is less, atthe design treatment rate. • Longitudinal slopes should not exceed 2.5% • Trapezoidal channels are normaUy recommended but other configurations, such as paraboUc, can also provide substantial water quaUty improvement and may be easier to mow than designs with sharp breaks in slope. • Swales constructed in cut are preferred, or in fill areas that are far enough from an adjacent slope to minimize the potential for gopher damage. Do not use side slopes constructed of GR, which are prone to structural damage by gophers and other burrowing animals. • A diverse selection of low growing, plants that thrive under the specific site, cUmatic, and watering conditions shouldbe specified. Vegetation whose growing season corresponds to the wet season are preferred. Drought tolerant vegetation should be considered especiaUy for swales that are not part of a regularly irrigated landscaped area. • The width of the swale should be determined using Manning's Equation using a value of 0.25 for Manning's n. 2 of 13 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www. caDmphancbooks. com TC-30 Vegetated Swale Table 1 Grassed swale pollutant removal efficiency data Removal Efficiencies (96 Removal) Study TSS TP TN NO3 Metals Bacteria Type Caltrans 2002 77 8 67 66 83-90 -33 dry swales Goldberg 1993 67.8 4.5 -31-4 42-62 -100 grassed channel Seattle Metro and Washington Department of Ecology 1992 60 45 --25 2-16 -25 grassed channel Seattle Metro and Washington Departinent of Ecology, 1992 83 29 --25 46-73 -25 grassed channel Wang et aL, 1981 80 ---70-80 -dry swale Dorman et al., 1989 98 18 -45 37-81 -dry swale Harper, 1988 87 83 84 80 88-90 -dry swale Kercher et al., 1983 99 99 99 99 99 -dry swale Harper, 1988. 81 17 40 52 37-69 -wet swale Koon, 1995 67 39 -9 -35 to 6 -wet swale WhUe it is difficult to distinguish between different designs based on the small amount of avaUable data, grassed channels generaUy have poorer removal rates tiian wet and dry swales, although some swales appear to export soluble phosphorus (Harper, 1988; Koon, 1995). It is not clear why swales export bacteria. One explanation is that bacteria thrive in the warm swale soUs. Siting Criteria The suitabUity of a swale at a site vriU depend on land use, size of the area serviced, soU type, slope, imperviousness of the contributing watershed, and dimensions and slope of the swale system (Schueler et al., 1992). In general, swales can be used to serve areas of less than 10 acres, with slopes no greater than 5 %. Use of natural topographic lows is encouraged and natural drainage courses should be regarded as significant local resources to be kept in use (Young et al., 1996). Selection Criteria (NCTCOG, 1993) • Comparable performance to wet basins • limited to treating a few acres • AvaUabiUty of water during diy periods to maintain vegetation • Sufficient available land area Research in the Austin area indicates that vegetated controls are effective at removing poUutants even when dormant Therefore, irrigation is not required to maintain growth during diy periods, but may be necessaiy only to prevent the vegetation fi-om dying. 4 of 13 California Stormwater BMP Handbook New Development and Redevelopment www. cabmpiiandbocks, com January 2003 Vegetated Swale TC-30 The topography of the site should permit tiie design of a channel witii appropriate slope and cross-sectional area. Site topography may also dictate a need for additional stmctiiral conti-ols Recommendations for longitiidinal slopes range between 2 and 6 percent. Flatiier slopes can be used, If sufficient to provide adequate conveyance. Steep slopes increase flow velocity decrease detention time, and may require energy dissipating and grade check. Steep slopes also can be managed usmg a senes of check dams to terrace tiie swale and reduce tiie slope to within acceptable Umits. Hie use of check dams witii swales also promotes uifiltration Additional Design Guidelines Most of tiie design guideUnes adopted for swale design specify a minimum hydrauUc residence time of 9 minutes. Tliis criterion is based on tiie results of a single stiidy conducted in Seattie Washington (Seattle Metiro and Washington Department of Ecology, 1992) and is not weU ' supported. Analysis of the data coUected in tiiat study indicates tiiat poUutmt removal at a residence ttme of 5 minutes was not significantiy different, altiiough there is more variabUity in tiiat data. Therefore, additional research in tiie design criteria for swales is needed. Substantial poUutant removal has also been observed for vegetated conti-ols designed solely for conveyance (Barrett et al, 1998); consequentiy, some flexibUity in tiie design is warranted. Many design guideUnes recommend tiiat grass be fi-equentiy mowed to maintain dense coverage near the ground surface. Recent research (ColweU et al., 2000) has shown mowing fi-equency or grass height has Httie or no effect on poUutant removal. o ^ j Summary of Design Recommendations 1) The swale should have a lengtii tiiat provides a minimum hydrauHc residence time of at least 10 minutes. The maximum bottom widtii should not exceed 10 feet unless a dividing berm is provided The deptii of flow should not exceed 2/3rds the height of tiie grass at the peak of tiie water quaUty design storm intensity. The channel slope shouldnot exceed 2.5%. 2) A design grass height of 6 inches is recommended. 3) Regardless of the recommended detention time, tiie swale should be not less tiian 100 feet in length. 4) The width of the swale should be determined using Manning's Equation, at the peak of the design storm, using a Manning's n of 0.25. 5) The swale can be sized as both a treatment faciUty for the design storm and as a conveyance system to pass tiie peak hydrauUc flows of tiie 100-year storm if it is located "on-Une." The side slopes shouldbe no steeper than 3:1 (H:V). 6) Roadside ditches should be regarded as significant potential swale/buffer strip sites and should be utiUzed for tiiis purpose whenever possible. If flow is to be introduced tiirough curb cuts, place pavement sUghtiy above tiie elevation oftiie vegetated areas. Curb cuts should be at least 12 inches wide to prevent clogging. 7) Swales must be vegetated in order to provide adequate treatment of runoff. It is important to maximize water contact with vegetation and the soU surface. For general purposes, sdectfine, close-growi^g, water-resistant grasses. If possible, divert runoff (other tiian necessary inigation) during the period of vegetation January 2003 California Stormwater BMP Hancbook 5 of 13 New Development and Redevelopment www.cabmpiiandbooks. com TC-30 Vegetated Swale estabUshment. Where runoff diversion is not possible, cover graded and seeded areas with suitable erosion control materials. Maintenance The useful life of a vegetated swale system is direcdy proportional to its maintenance frequency. If properly designed and regularly maintained, vegetated swales can last indefinitely. The maintenance obj ectives for vegetated swale systems include keeping up the hydrauHc and removal effidency of the channel and maintaining a dense, healthy grass cover. Maintenance activities should include periodic movring (with grass never cut shorter than the design flow depth), weed control, watering during drought conditions, reseeding of bare areas, and clearing of debris and blockages. Cuttings should be removed from the channel and disposed in a local composting facUity. Accumulated sediment should also be removed manuaUy to avoid concentrated flows in the swale. The appUcation of fertiHzers and pesticides should be minimal. Another aspect of a good maintenance plan is repairing damaged areas within a channel. For example, if the channel develops ruts or holes, it should be repaired utiUzing a suitable soil that is properly tamped and seeded. The grass cover should be thick; if itis not, reseed as necessary. Any standing water removed during the maintenance operation must be disposed to a sanitary sewer at an approved discharge location. Residuals (e.g., sUt, grass cuttings) must be disposed in accordance with local or State requirements. Maintenance of grassed swales mostiy involves maintenance of the grass or wetiand plant cover. Typical maintenance activities are summarized below: • Inspect swales at least twice annuaUy for erosion, damage to vegetation, and sediment and debris accumulation preferably at the end of the wet season to schedule summer maintenance and before maj or faU nmoff to be sure the swale is ready for winter. However, additional inspection after periods of heavy nmoff is desirable. The swale should be checked for debris and Htter, and areas of sediment accumulation. • Grass height and mowing frequency may not have a large impact on poUutant removal. Consequentiy, mowing may only be necessaiy once or twice a year for safety or aesthetics or to suppress weeds and woody vegetation. • Trash tends to accumulate in swale areas, particularly along highways. The need for litter removal is determined through periodic inspection, but Htter should always be removed prior to movring. • Sediment accumulating near culverts and in channels should be removed when it builds up to 75 mm (3 in.) at any spot, or covers vegetation • Regularly inspect swales forpools of standing water. Swales can become a nuisance dueto mosquito breeding in standing water if obstructions develop (e.g. debris accumulation, invasive vegetation) and/or if proper drainage slopes are not implemented and maintained. 6 of 13 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www. cabmphancbooks. com Vegetated Swale TC-30 Cost Construction Cost Littie data is avaUable to estimate the difference in cost between various swale designs. One study (SWRPC, 1991) estimated the construction cost of grassed channels at approximately $0.25 per ft?. This price does not include design costs or contingencies. Brown and Schueler (1997) estimate these costs at approximately 32 percent of construction costs for most stormwater management practices. For swales, however, these costs would probably be significantiy higher since the construction costs are so low compared with other practices. A more reaUstic estimate would be a total cost of approximately $0.50 per ft?, which compares favorably with other stormwater management practices. January 2003 Califomia Stormwater BMP Handbook 7 of 13 New Development and Redevelopment www.cabmphandbooks.com TC-30 Vegetated Swale Table 2 Swale Cost Estimate (SEWRPC, 1991) ^rait^^ft^r r;rri:r"" ^ 'Area grubbed = (fopwidth x swale length) Area tilled - (top width . mmieMmflx sivale tength (parabolic aoss-sedton) J(top width) ' Area seated = area cleared x 0.5. • Ansa sodded = area cleared x 0.5. 8 of 13 California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbooks.com January 2003 Vegetated Swale Table 3 Estimated Maintenance Costs (SEWRPC, 1991) TC-30 Component Lawn Mowing General Lawn Care SyinateDrtriaend Ufter Rem wal Grass RaseedhgwHh Mulcti and FertllljBr Unit Cost $0.85/1,000 ff/mowing «S.O0n,O0Off'/yBar *0.10/linear foot/year $0.30/yd' Swale Size (Deptti and Top VWdthJ 1.5 Foot Depth. One- Foot Bottom Width, 10-Foot Top Width J0.t4/linearfoot 10.18/Ihaar fool S0.10/linearfoot $0.01 /lireairfoof 3-Fool Depth. 3-Foot Bottom VWdth, 21-Foot Top Width W.21/linearfoot iO .28/linearfoot W.IO/finear foot 10.01 /linear foot Comment Lavm maintenance areB=(top width + 10 fEot)x length. Mow eight times par year Lawn maintenance area " (lop widths lOfBaPxIanalh Area navogatalsd equals 1% lawi matntenancB area per yoar January 2003 California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbooks.com 9 of 13 TC-30 Vegetated Swale Maintenance Cost r:?:ri:eiy^^^^ mowing, tiie cost is fundamentX aXcSon off^^^^ ^ maintenance consists of SEWRPC are shown in TaWrHJ m^v^!?/ .^^^^ frequency Unit costs developed by runoff and would^qSre pSdic^^^^^^ T'^^'^ "^"^'^^ be used to convey ^ water quaHty compoS Sfe^nS^^^^^^ management, no s^ frainingrSt'SS^^^^^ T^TAT? ^"^ of Additional Information EnmronmentalEngineering, Vd. 124, No. n, pp^Ti™ ' ^'^•^•^<"™'" »/ Watershed Protection.S;SS^D. ^"^^^^^^ Chicago. byU>eCe:S^S5^:Sr^=*SS?irMa'"'^ Resources Management DeDartnSrfr?j?3? ^ '^"'^ Water Washington. Seatfe; WA of GiyJ and Envmmmental Engineering, Umvemty of S^Z^^r^- *f'™^"--^-'=»«o.5h,d^. SeatfleEr^ne^Depar^en^ Environmental Researcli and Design, Inc., Orlando, p^"""^ laMahassee, FL, by ciK J ^4 39.uaKiand, F.H. 1983. An evaluation of stonnwater poUutant removal California Stormwater BMP Handbook New Development and Redevelopment www. cabmphandbooks. com January 2003 Department of CivU Engineering, Seattie, WA umversity ot Washington, ^s™"?" °' r'^i ^l"*^'- of Rwioff Controb on tke Qumtitu and QuaHtv of Flonda andFlonda Department of Transportation, Orlando, FL. ''"'^^^^ °f ^^t^ai Information Resources MaiylandDepartment oftiie Environment(MDE). 2000. Maryland Stormwater Desian ™ndestate.mdus/env.VonT...t/w^. /e.. J^,,,,, T uTIf,,, TC-30 Washington Department of Ecology, Olympia, WA Of Water. Washington, DC, by tiie Watershed Management Institiite, IngTiMe^Mcf ^' California Stormwater BMP Handbook New Development and Redevelopment www. cabmphandbooks. com January 2003 Vegetated Swale TC-30 I'rovidc ftjf scour proteaion. (•) Cnwa xrthm uf *w.le with rhtck <1<. UotiUan: L =i-«n9«ho<«wa(»iinfK>un4i>wntarMporiai«*rfM/m ,f s, - e«tt«m Upa ot iwik! (fdtt) w =Tot»wW»iold>.citrfjm{fp. »Va = Bottom whShalelKs* dam (ft! Z« = Rado ef hanicwal to vortical elung» in swil» sido step., (ftft) California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbooks.com 13 of 13 ATTACHMENT "A" VICINITY MAP VICINITY MAP ATTACHMENT "B" SITEMAP ATTACHMENT "C" STORM WATER REQUIREMENTS APPLICABILITY CHECKLIST storm Water Standards 4/03/03 VI. RESOURCES & REFERENCES APPENDIXA STORM WATER REQUIREMENTS APPLICABILITY CHECKLIST Complete Sections 1 and 2 of the following checklist to determine your project's permanent and construction storm water best management practices requirements. This form must be completed and submitted with your permit application. Section 1. Permanent Storm Water BMP Requirements: If any answers to Part A are answered "Yes," your project is subject to the "Priority Project Permanent Storm Water BMP Requirements," and "Standard Permanent Storm Water BMP Requirements" in Section III, "Permanent Storm Water BMP Selection Procedure" in the Sform Water Standards manual. If all answers to Part A are "No," and any answers to Part B are "Yes," your project is only subject to the "Standard Permanent Storm Water BMP Requirements". If every question in Part A and B is answered "No," your project is exempt from permanent storm water requirements. Part A: Determine Priority Project Permanent Storm Water BMP Requirements Does the project meet the definition of one or more of the priority project categories?* Yes No 1. Detached residential development of 10 or more units X 2. Attached residential development of 10 or more units X 3. Commercial development greater than 100,000 square feet X 4. Automotive repair shop 5. Restaurant X 6. Steep hillside development greater than 5,000 square feet X 7. Project discharging to receiving waters within Environmentally Sensitive Areas X 8. Parking lots greater than or equal to 5,000 ft'' or with at least 15 parking spaces, and potentially exposed to urban runoff X 9. Streets, roads, highways, and freeways which wouid create a new paved surface that is 5,000 square feet or greater X * Refer to the definitions section in the Sform Water Standards for expanded definitions ofthe priority project categories. Umited Exclusion: Trenching and resurfacing work associated with utility projects are not considered priority projects. Parking lots, buildings and other structures associated with utility projects are priority projects if one or more of the criteria in Part A is met. If all answers to Part A are "No", continue to Part B. 30 storm Water Standards 4/03/03 Does the project propose: Yes No 1. New impervious areas, such as rooftops, roads, parking lots, driveways, paths and sidewalks? X 2. New pervious landscape areas and irrigation systems? X 3. Permanent structures within 100 feet of any natural water body? X 4. Trash storage areas? X 5. Liquid or solid material loading and unloading areas? X 6. Vehicle or equipment fueling, washing, or maintenance areas? •X 7. Require a General NPDES Permit for Storm Water Discharges Associated with Industrial Activities (Except construction)?* X 8. Commercial or industrial waste handling or storage, excluding typical office or household waste? X 9. Any grading or ground disturbance during construction? X 10. Any new storm drains, or alteration to existing storm drains? X *To find out if your project is required to obtain an individual General NPDES Permit for Storm Water Discharges Associated with Industrial Activities, visit the State Water Resources Control Board web site at, www.swrcb.ca.gov/stormwtr/industrial.html Section 2. Construction Storm Water BMP Requirements: If the answer to question 1 of Part C is answered "Yes," your project is subject to Section IV, "Construction Storm Water BMP Performance Standards," and must prepare a Storm Water Pollution Prevention Plan (SWPPP). If the answer to question 1 is "No," but the answer to any of the remaining questions is "Yes," your project is subject to Section IV, "Construction Storm Water BMP Performance Standards," and must prepare a Water Pollution Control Plan (WPCP). If every question in Part C is answered "No," your project is exempt from any construction storm water BMP requirements. If any of the answers to the questions in Part C are "Yes," complete the construction site prioritization in Part D, below. PartC: Determine Construction Phase Storm Water Requirements Would the project meet any ofthese criteria during construction? Yes No 1. Is the project subject to California's statewide General NPDES Permit for Storm Water Discharges Associated With Construction Activities? X 2. Does the project propose grading or soil disturbance? X 3. Would storm water or urban runoff have the potential to contact any portion of the construction area, including washing and staging areas? X 4. Would the project use any construction materials that could negatively affect water quality if discharged from the site (such as, paints, solvents, concrete, and stucco)? X 31 storm Water Standards 4/03/03 Part D: Determine Construction Site Priority In accordance with the Municipal Permit, each construction site with construction storm water BMP requirements must be designated with a priority: high, medium or low. This prioritization must be completed with this form, noted on the plans, and included in the SWPPP or WPCP. Indicate the project's priority in one of the check boxes using the criteria below, and existing and surrounding conditions of the project, the type of activities necessary to complete the construction and any other extenuating circumstances that may pose a threat to water quality. The City reserves the right to adjust the priority of the projects both before and during construction. [Note: The construction priority does NOT change construction BMP requirements that apply to projects; all construction BMP requirements must be identified on a case-by-case basis. The construction priority does affect the frequency of inspections that will be conducted by City staff. See Section IV.1 for more details on construction BMP requirements.] A) High Priority 1) Projects where the site is 50 acres or more and grading will occur during the rainy season 2) Projects 5 acres or more. 3) Projects 5 acres or more within or directly adjacent to or discharging directly to a coastal lagoon or other receiving water within an environmentally sensitive area Projects, active or inactive, adjacent or tributary to sensitive water bodies • B) Medium Priority 1) Capital Improvement Projects where grading occurs, however a Storm Water Pollution Prevention Plan (SWPPP) is not required under the State General Construction Permit (i.e., water and sewer replacement projects, intersection and street re-alignments, widening, comfort stations, etc.) 2) Permit projects in the public right-of-way where grading occurs, such as installation of sidewalk, substantial retaining walls, curb and gutter for an entire street frontage, etc. , however SWPPPs are not required. 3) Permit projects on private property where grading permits are required, however. Notice Of Intents (NOIs) and SWPPPs are not required. • C) Low Priority 1) Capital Projects where minimal to no grading occurs, such as signal light and loop installations, street light installations, etc. 2) Permit projects in the public right-of-way where minimal to no grading occurs, such as pedestrian ramps, driveway additions, small retaining walls, etc. 3) Permit projects on private property where grading permits are not required, such as small retaining walls, single-family homes, small tenant improvements, etc. 32