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GPA 06-03; Rancho Milagro MND Attachment 9; General Plan Amendment (GPA)
STORMWATER MANAGEMENT PLAN FOR CITY OF CARLSBAD TRACT NO. 06-04 A 19 HOME / 25 LOT RESIDENTIAL DEVELOPMENT PREPARED FOR RANCHO MILAGRO LYALL ENTERPRISE, INC. 15529 HIGHWAY 79 PAUMA VALLEY, CA 92061 MARCH 9, 2009 PREPARED BY: MANITOU ENGE^nEERING COMPANY 350 WEST NINTH AVENUE, SUITE B ESCONDIDO, CA 92025 (760) 741-9921 JN 1674 RECEIVED MAY U 2009 CtTY OF CARLSBAD PLANNING DEPT Sao.'' SECTION 1 NEW DEVELOPMENT PRIORITY PROJECT TYPE Does you project meet one or more of the following criteria: YES NO 1. Home subdivision of 100 units or more. Includes SFD, MFD, Condominium and Apartments K 2. Residential development of 10 units or more. Includes SFD, MFD, Condominium and Apartments X 3. Commercial and industrial deveiopment areater than 100,000 souare feet inciudinq paridna areas. Any development on private land that is not fcr heavy industrial or residential uses. Example: Hospitals, Hotels, Recreational Facilities, Shopping Malls, etc. X 4. Heavv industriai/Industrv areater than 1 acre (NEED SIC CODES FOR PERMIT BUSINESS TYPES) SIC codes 5013, 5014, 5541, 7532-7534, and 7536-7539 X 5. Automotive repair shop. SIC codes 5013, 5014, 5541, 7532-7534, and 7536-7539 X 6. A New Restaurant where the land area of development is 5.000 sauare feet or more inciudina parkina areas. SIC code 5812 X 7. Hillside development (1) greater than 5,000 square feet of impervious surface area and (2) development will grade on any natural slope that is 25% or greater X 8, Environmentallv Sensitive Area (ESA). Impen/ious surface of 2,500 square feet or more located v^/ithin, "directly adjacent"^ to (within 200 feet), or "discharging directly to"^ receiving water within the ESA^ X 9. Parl<ina iot. Area of 5,000 square feet or more, or with 15 or more parking spaces, and potentially exposed to urban runoff X 10. Retail Gasoline Outlets - sen/ina more than 100 vehicles per dav Serving more than 100 vehicles per day and greater than 5,000 square feet \ 11. Streets, roads drivewavs, hiahwavs. and freewavs. Project would create a new paved surface that is 5,000 square feet or greater. X 12. Coastal Development Zone. Within 200 feet of the Pacific Ocean and (1) creates more than 2500 square feet of impermeable surface or (2) increases impermeable surface on property by more than 10%. 1 Environmentally Sensitive Areas include but are not limited to all Clean-Water Act Section 303(d) impaired water bodies; areas designated as Areas of Special Biological Significance by the State Water Resources Control Board (Water Quality Control Plan for the San Diego Basin (1994) and amendments); water bodies dejsignated with the RARE beneficial use by the State Water Resources Control Board (Water Quality Control Plan for the San Diego Basin (1994) and amendments); areas designated as preserves or their equivalent under the Multi Species Conservation Program within the Cities and Count of San Diego; and any other equivalent environmentally sensitive areas which have been identified by the Copermittees. 2 "Directly adjacent" means situated within 200 feet ofthe environmentally sensitive area. 3 "Discharging directly to" means outflow from a drainage conveyance system that is composed entirely of flows from the subject development or redevelopment site, and not commingled with flow from adjacent lands. Section 1 Results: If you answered YES to ANY ofthe questions above you have a PRIORITY project and PRIORITY project requirements DO apply. A Storm Water Management Plan, prepared in accordance with City Storm Water Standards, must be submitted at time of application. Please check the "MEETS PRIORITY REQUIREMENTS" box in Section 3. If you answered NO to ALL of the questions above, then you are a NON-PRIORITY project and STANDARD requirements apply. Piease check the "DQES NOT MEET PRIORITY Requirements" box in Section 3, SWMP Rev 6/4/08 SECTION 2 SIGNiFiCANT REDEVELOPMENT: YES NO 1. Is the project redeveloping an existing priority project type? (Priority projects are defined in Section 1) K If you answered YES, please proceed to question 2. If you answered NO, then you ARE NOT a significant redevelopment and you ARE NOT subject to PRIORITY project requirements, only STANDARD requirements. Please check the "DOES NOT MEET PRIORITY Requirements" box in Section 3 below. 2. Is the project solely limited to one of the following: a. Trenching and resurfacing associated with utility work? b. Resurfacing and reconfiguring existing surface parking lots? c. New sidewalk construction, pedestrian ramps, or bike lane on public and/or private existing roads? d. Replacement of existing damaged pavement? If you answered NO to ALL ofthe questions, then proceed to Question 3. If you answered YES to ONE OR MORE ofthe questions then you ARE NOT a significant redevelopment and you ARE NOT subject to PRIORITY project requirements, only STANDARD requirements. Please check the "DOES NOT MEET PRIORITY Requirements" box in Sectjipn 3 below. 3. Will the development create, replace, or add at least 5,0!do square feet of impervious surfaces on an existing development or, be Ipcated within 200 feet of the Pacific Ocean and (l)create more than 2500 square feet of impermeable surface or (2) increases impermeable surface on property by more than 10%? If you answered YES, you ARE a significant redevelopment, and you ARE subject to PRIORITY project requirements. Please check the "MEETS PRIORITY REQUIREMENTS" box in Section 3 below. If you answered NO, you ARE NOT a significant redevelopment, and you ARE NOT subject to PRIORITY project requirements, oniy STANDARD requirements. Piease check the "DOES NOT MEET PRIORITY Requirements" box in Section 3 below. SECTION 3 Questionnaire Results: ^ MY PROJECT MEETS PRIORITY REQUIREMENTS, MUST COMPLY WITH PRIORITY PROJECT STANDARDS AND MUST PREPARE A STORM WATER MANAGEMENT PLAN FOR SUBMITTAL AT TIME OF APPLICATION. • MY PROJECT DOES NOT MEET PRIORITY REQUIREMENTS AND MUST ONLY COMPLY WITH STANDARD STORM WATER REQUIREMENTS. Applicant Information and Signature Box This Box /or Cily Use Only Address: JT^JH JJIhl^^'^K IC Assessors Parqel Number(s): fhVi^JX VC^lUy. £A?2o6) ^•-zc,^ • OIO-ot Applicant Name: Applicant Title: Applicant Signature: Date; City Concurrence: YES By: Praject ID: SWMP Rev 6/4/08 TABLE OF CONTENTS Project Description 2 Topography and Land Use 2 Hydrologic Unit Contribution 5 Watershed 5 Pollutants of Concern 6 Site Design/LID Design 7 Source Control 11 Treatment Control 15 Maintenance 18 ATTACHMENTS A. Location Map/Site Map B. BMP Map C. BMP Datasheets/Hydraulics/Operation and Maintenance D. Engineer's Certification Sheet Storm Water Management Plan For Priority Projects (Major SWMP) The Major Stormwater Management Plan (Major SWMP) must be completed in its entirety and accompany applications to the Cot'^^^' for a permit or approval associated with certain types of development projects. To determine whether yonr project is required to submit a Major or Minor SWMP, please reference the City's Stormwater Intake Form for Development Projects. Project Name: Rancho Milagro Applicant: Lyall Enterprise Inc. Applicant's Address: 15529 Highway 79 Pauma Valley, CA. 92061 Plan Prepared: Manitou Engineering Company 350 West 9* Ave., Suite "B" Escondido, CA. 92025 Date: 03/09/2009 Revision Date (If applicable): The piupose of the SWMP is to describe how the project will minimize the short and long-term impacts on receiving water quality. Projects that meet the criteria for a priority development project are required to prepare a Major SWMP. Since the SWMP is a fmal engineering document, revisions may be done by amendment only. Completion of the following checklists and attachments will fulfill the requirements ofa Major SWMP for the project listed above. c PROJECT DESCRIPTION Please provide a brief description ofthe project in the following box. Please include: • Project Location • Project Description • Physical Features (Topography) • Surrounding Land Use • Proposed Project Land Use • Location of dry weather flows within project limits, if applicable. c The proposed project, Rancho Milagro, Carlsbad Tract No. 06-04 is located in the Northeast Quadrant of the City of Carlsbad. The project is govemed by two City overlay zones, Local Facilities Management Pian, Zone 15 and the Sunny Creek Specific Plan, SP 191. The project is located north of El Camino Real and East of the proposed northerly extension of College Boulevard. Vehicle access to the site, from College Boulevard, is proposed by Carlsbad Tract No. 00-18 and is shown as "A" and "K" streets. The project proposes nineteen (19) one half-acre minimum, lots and one (1) HOA maintained lot and five (4) open space lots. One Open Space Lot contains Agua Hedionda Creek and all the flood plain and riparian habitat surrounding the Creek, within the project boundaries. The remaining Open Space lots include the Coastal Sage on the south facing slope tributary to Agua Hedionda Creek and the northerly riparian area that traverses the site from the west to east. The project complies with the city of Carlsbad Hillside Development Ordinance. The project includes a single loaded spine road that provides motorist and pedestrians with a window to the Agua Hedionda natural resources. The knuckle, in the spine road, at the Agua Hedionda Creek overlook area is proposed as a traffic-calming device. The forty-two and two tenths acre (42.2 +1- ac.) site is divided north/south by a ridge that runs east/west through the northerly third of the site. Elevations range from a low of seventy feet to a high of two hundred and ten feet on the east/west ridge. The surrounding land uses are residential south of Agua Hedionda Creek, a single home with equestrian facilities to the west, agricultural/ proposed Tract No. 00-18 to the north, agricultural uses and scattered residences to the east of the project site. Run-off from the project's south facing slope flows directly to Agua Hedionda Creek and the remainder of the site drains to the northerly intermittent watercourse that flows westerly to a small pond on the equestrian property to the west and then to the Agua Hedionda Creek. The Creek flows through the Rancho Carlsbad Golf Course, the Rancho Carlsbad Mobile Home Park, under El Camino Real, into Agua Hedionda Lagoon, through the inner lagoon, under Interstate 5 to the middle lagan, under the railroad fracts to the outer lagoon and the Encina power plant intake area and under Carlsbad Boulevard (Old Highway 101) to the Pacific Ocean. The distance form the site to the Ocean is approximately two thousand two hundred (220 feet. HYDROMODIFICATION DETERMINATION The following questions provide a guide to collecting information relevant to hydromodification management issues. Table 2 QUESTION YES NO Information 1. Will the proposed project disturb 50 or More acres of land? (Includmg all phases Of development) X IfYES, continue to 2. If NO, go to 6. 2. Would the project site discharge directly Into channels that are concrete-lines or Significantly hardened such as with rip-rap, sackcrete, etc, downstream to their outfall Into bays or the ocean? IfNO, continue to 3. IfYES, go to 6. 3. Would the project site discharge directly into underground storm drains discharging dkectiy to bays or the ocean? IfNO, Continue to 4. IfYES, go to 6. 4. Would the project site discharge directly to a channel (lined or un-lined) and the combmed impervious surface downstream firom the project site to discharge at the ocean or bay are 70% or greater? IfNO, contmue to 5. IfYES, goto 6. 5. Project is required to manage Hydromodification unpacts. Hydromodific ation Management Required as described in Section 67.812 b(4) ofthe WPO. 6. Project is not required to manage Hydromodification impacts. An exemption is potentially available for projects that are required (No. 5. in Table 2 above) to manage hydromodification impacts: The project proponent may conduct an independent geomorphic study to determine the project's full hydromodification impact. The study must incorporate sediment transport modeling across the range of geomorphically-significant flows and demonstrate to the County's satisfaction that the project flows and sediment reductions will not detrimentally affect the receivmg water to qualify for the exemption. STORMWATER QUALITY DETERMINATION Following questions provide a guide to collecting information relevant to project stormwater quality issues. Please provide the following information in a printed report accompanying this form. Table 3 QUESTIONS COMPLETED NA 1. Describe the topography of the project area. X 2. Describe the local land use within the project area and adjacent areas. X 3. Evaluate the presence of dry weather flow. X 4. Determine the receiving waters that may be affected by the project throughout all phases of development through completion (i.e., constmction, long term maintenance and operation). X 5. For the project limits, list the 303(d) impaired receiving water bodies and their constituents of concem. X 6. Determine if there are any High Risk Area (which is defined by the presence or groundwater percolation facilities) within the project limits. X 7. Determine the Regional Boards special requirements, including TMDL's, effluent limits, etc. X 8. Determine the general climate of the project area. Identify annual rainfall and rainfall intensity curves. X 9. Determine the soil classification, permeability, erodibility, and depth to groundwater for Treatment BMP consideration. X 10. Determine contaminated or hazardous soils within the project area. X 11. Determine if this project is within the environmentally sensitive areas as defined on the maps in Appendix A of the County of San Diego Standard Urban Storm Water Mitigation Plan for Land Development and Public Improvement Projects. X 12. Determine if this is an emergency project. X WATERSHED • San Juan 901 • Santa Margarita 902 • San Luis Rey 903 X Carlsbad 904 • San Dieguito 905 • Penasquitos 906 • San Diego 907 • Sweetwater 909 • Otay 910 • Tijuana 911 • Whitewater 719 • Clark 720 • West Salton 721 • Anza Borrego 722 • Imperial 723 Please provide the hydrologic sub-area and number(s) Niunber Name 904.31 Agua Hedionda Creek Please provide the beneficial uses for Inland Surface Waters and Ground Waters. Beneficial Uses can be obtained from the Water Quality Control Plan for the San Diego Basm, which is available at the Regional Board office or at http://www.waterboards.ca.gov/sandiego/water issues/programs/l^asin plan/index.shtml SURFACE WATERS Hydrologic Unit Basin Number MUN AGR IND PROC GWR FRESH POW RECl REC2 BIOL WARM COLD WILD RARE SPWN Inland Surface Waters r Agua Hedionda Creek 4.31 X X X X X X X X X Ground Waters Agua Hedionda Creek 4.31 X X X * Excepted from Municipal X Existing Beneficial Use 0 Potential Beneficial Use ^^^^ POLLUTANTS OF CONCERN Using Table 4, identify pollutants that are anticipated to be generated from the proposed priority project categories. Pollutants associated with any hazardous material sites that have been remediated or are not threatened by the proposed project are not considered a pollutant of concem. Table 4. Anticipated and Potential Pollutants Generated by Land Use Type PDP Categories General Pollutant Categories Sediments Nutrients Heavy Metals Organic Compounds Trash & Debris Oxygen Demanding Substances Oil& Grease Bacteria & Viruses Pesticides Detached Residential development X X Attached Residential Development X X X P(l) P(2) X Commercial Development 1 Acre or greater P(l) P(l) P(2) X P(5) P(3) P(5) Heavy industry /industrial development X X X X X X Automotive Repair Shops X(4)(5) X Restaurants X X X Hillside Development >5,000 ft^ X X X X Parking Lots P(l) P(l) X X P(l) X P(i) Retail Gasoline Outlets X X X X Street, Highways & Freeways X X X X(4) X X X X= anticipatec P= Potential (1) A Potential pollutant if landscaping exist on-site. (2) A potential pollutant if the project included uncovered parking areas. (3) A potential pollutant if land use involves food or animal waste products. (4) Including pefroleum hydrocarbons. (5) Including solvents. Note: If other monitoring date that is relevant to the project is available. Please include as Attachment C. RECEIVING WATERS: The receiving waters for the runoff generated by this project is the Agua Hedionda Creek. The impairments to the downstream waters per the 303 d list are at the Agua Hedionda Creek caused by Manganese, Selenium, Sulfates and TDS. At the Agua Hedionda Lagoon the impairments are Indicator bacteria, and Sedimentation/Siltation. Therefore the pollutants of concern for this project are Heavy metals, TDS, Sulfates, TDS, Silts, and Indicator Bacteria. SITE DESIGN To minimize stormwater impacts, site .•".esign nii^astu'e musi be addressed. The following Checklist provides options for avoiding or reducing potential impacts during project Table 6 OPTIONS YES NO N/A 1. Has the project been located and road improvement aligned to avoid or minimize impacts to receiving waters or to increase the preservation of criticai (or problematic) areas such as floodplains, steep slopes, wetlandsi, and areas with erosive or unstable soil conditions? X 2. Is the project designed to minimize impervious footprint? X 3. Is the project conserving natural areas where feasible? X 4. Where landscape is proposed, are rooftopSj impervious sidewalks, walkways, trails and patios be drained into adjacent landscaping? X 5. For roadway projects, are structures and bridges be designed or located to reduce work in live streams and minimize construction impacts? X 6. Can any of the following methods be utilized to minimize erosion from slopes: 6.a. Disturbing existing slopes only when necessary? X 6.b. Minimize cut and fill areas to reduce slope length? X 6.C. Incorporating retaining walls to reduice steepness of Slopes or to shorten slopes? X 6.d. Providing benches or terraces on hi^ cut and fill Slopes to reduce concentration of fldws? X 6.e. Rounding and shaping slopes to redijice concentrated flow? X 6.f Collecting concentrated flows in stabilized drains and channels? X LOW IMPACT DEVELOPMENT (LID) Each numbered item is a LID requkement ofthe WPO. Please check the box(s) under each number that best describes the LOW Impact Development BMP(s) selected for this project Table 7 1 • Conserve natural Areas, Soils, and Vegetation-County LID Handbook 2.2.1 X Preserve well draining soils (Type A or B) X Preserve Significant Trees • Other. Description: o 1. Not feasible. State Reason: 2. Minimize Disturbance to Natural Drainage-County LID Handbook 2.2.2 • Set-back development envelope from drainages X Restrict heavy construction equipment access to planned green/open Space areas • Other. Description: • Not feasible. State Reason. 3. Minimize and Disconnect Impervious Surface (see 5) -County LID Handbook 2.2.3 X Clustered Lot Design X Items checked in 5? • Other. Description: • 3. Not feasible. State Reason: 4. Minimize Soil Compaction-County LID Handbook 2.2.4 • Restrict heavy construction equipment access to planned green/open • Space areas X Re-till soils compacted by construction vehicles/equipment • Collect & re-use upper soil layers of development site containing organic • materials • Qther. Description 4.Not feasible. State Reason: 5. Drain Runoff from Impervious Surfaces to Pervious Area-County LID Handbook 2.2.5 ^^^^ LID Street & Road Design • Curb-cuts to landscaping • Rural Swales • Concave Median • Cul-de-sac • Landscaping Design • Other Description: LID Parking Lot Design • Permeable Pavements • Curb-cuts to landscaping • Other. Description: LID Driveway, Sidewalk, Bike-path Design • Permeable Pavements • Pitch pavement towards landscaping • Other. Description: LID Building Design • Cistems & Rain Barrels X Downspout to swale • Vegetated Roofs • Other. Description: LID Landscaping Design • Soil Amend X Reuse of Native Soils X Smart Irrigation Systems • Street Tree • Other. Description: 5. Not feasible. State Reason: CHANNELS & DRAINAGES Complete the following checklist to determine ifthe project includes work in channels. Table 8 No. CRITERIA YES NO N/A COMMENTS 1. Will the project include work in channels? X IfYES go to 2 IfNO goto 13 2. Will the project increase velocity or volume of downstream flow? IfYES go to 6. 3. Will the project discharge to unlined channels? IfYES go to. 6. 4. Will the project increase potential sediment load of downstream flow? IfYES go to 6. 5. Will the project encroach, cross, realign, or cause other hydraulic changes to a stream that may affect downsfream channel stability? IfYES go to 8. 6. Review channel lining materials and design for sfream bank erosion. Continue to 7. 7. Consider channel erosion control measures within the project limits as well as downsfream. Consider scour velocity. Continue to 8. 8. Include, where appropriate, energy dissipation devices at culverts. Continue to 9. 9. Ensure all fransitions between culvert outlets/headwalls/wingwalls and channels are smooth to reduce turbulence and scour. Continue to 10. 10. Include, if appropriate, detention facilities to reduce peak discharges. Continue to 11. 11. "Hardening" natural downsfream areas to prevent erosion is not an acceptable technique for protecting channel slopes, unless pre-development conditions are determined to be so erosive that hardening would be reqmred even in the absence of the proposed development Continue to 12. 12. Provide other design principles that are comparable and equally effective. Continue to 13. 13. End 10 SOURCE CONTROL Please complete the following checklist for Source Control BMPs. Ifthe BMP is not applicable for this project, then check N/A only at the main category. Table c BMP YES NO N/A 1. Provide Storm Drain System Stenciling and Signage l.a. All storm drain inlets and catch basins within the project area shall have a stencil or tile placed with prohibitive language (such as: "NO DUMPING - DRAINS TO ") and/or graphical icons to discourage illegal dumping. X l.b. Signs and prohibitive language and/or graphical icons, which prohibit illegal dumping, must be posted at public access points along channels and creeks within the project area. X 2. Design Outdoors Material Storage Areas to Reduce Pollution Introduction X 2.a. This is a detached single-family residential project. Therefore, personal storage areas are exempt from this requirement. X 2.b. Hazardous materials with the potential to contaminate urban runoff shall either be: (1) placed in an enclosure such as, but not limited to, a cabinet, shed, or similar structure that prevents contact with runoff or spillage to the storm water conveyance system; or (2) protected by secondary containment structures such as berms, dikes, or curbs. 2.C. The storage area shall be paved and sufficiently impervious to contain leaks and spills. 2.d. The storage area shall have a roof or awning to minimize direct precipitation within the secondary containment area. 3. Design Trash Storage Areas to Reduce Pollution Introduction X 3.a. Paved with an impervious surface, designed not to allow run-on from adjoining areas, screened or walled to prevent off-site transport of trash; or. 3.b. Provide attached lids on all trash containers that exclude rain, or roof or awning to minimize direct precipitation. 4. Use Efficient Irrigation Systems & Landscape Design The following methods to reduce excessive irrigation runoff shall be considered, and incorporated and implemented where determined applicable and feasible. 4.a. Employing rain shutoff devices to prevent irrigation after precipitation. X 4.b. Designing irrigation systems to each landscape area's specific water requirements. X 4.C. Using flow reducers or shutoff valves triggered by a pressure drop to control water loss in the event of broken sprinkler heads or lines. X 4.d. Employing other comparable, equally effective, methods to reduce irrigation water runoff X 5. Private Roads X II BMP YES NO N/A The design of private roadway drainage shall use at least one of the following 5.a. Rural swale system: sfreet sheet flows to vegetated swale or gravel shoulder, curbs at sfreet comers, culverts under driveways and street crossings. 5.b. Urban curb/swale system: street slopes to curb, periodic swale inlets drain to vegetated swale/biofilter. 5.C. Dual drainage system: First flush captured in street catch basins and discharged to adjacent vegetated swale or gravel shoulder, high flows connect directly to storm water conveyance system. 5.d. Other methods that are comparable and equally effective within the project. 6. Residential Driveways & Guest Parking X The design of driveways and private residential parking areas shall use one at least of the following features. 6.a. Design driveways with shared access, flared (single lane at street) or wheelstrips (paving only under tires); or, drain into landscaping prior to discharging to the storm water conveyance system. 6.b. Uncovered temporary or guest parking on private residential lots may be: paved with a permeable surface; or, designed to drain into landscaping prior to discharging to the storm water conveyance system. 6.C. Other features which are comparable and equally effective. 7. Dock Areas X Loading/unloading dock areas shall include the following. 7.a. Cover loading dock areas, or design drainage to preclude urban run-on and runoff. 7.b. Direct connections to storm drains from depressed loading docks (truck wells) are prohibited. 7.C. Other features which are comparable and equally effective. 8. Maintenance Bays X Maintenance bays shall include the following. 8.a. Repair/maintenance bays shall be indoors; or, designed to preclude urban run-on and runoff. 8.b. Design a repair/maintenance bay drainage system to capture all wash water, leaks and spills. Connect drains to a sump for collecdon and disposal. Direct cormection of the repair/maintenance bays to the storm drain system is prohibited. If required by local jurisdiction, obtain an Industrial Waste Discharge Permit. 8.C. Other features which are comparable and equally effective. 9. Vehicle Wash Areas X 9.a. Self-contained; or covered with a roof or overhang. 9.b Equipped with a clarifier or other pretreatment facility. 9.C, Properly cormected to a sanitary sewer. 9.d. Other features which are comparable and equally effective. 12 BMP YES NO N/A The design of private roadway drainage shall use at least one of the following S.a. Rural swale system: street sheet flows to vegetated swale or gravel shoulder, curbs at sfreet comers, culverts under driveways and sfreet crossings. 5.b. Urban curb/swale system: street slopes to curb, periodic swale mlets drain to vegetated swale^iofllter. 5.C. Dual drainage system: First flush captured in sfreet catch basins and discharged to adjacent vegetated swale or gravel shoulder, high flows connect directly to storm water conveyance system. 5.d. Other methods that are comparable and equally effective within the project. 6. Residential Driveways & Guest Parking X The design of driveways and private residential parking areas shall use one at least of the following features. 6.a. Design driveways with shared access, flared (single lane at street) or wheelstrips (paving only under tires); or, drain into landscaping prior to discharging to the storm water conveyance system. 6.b. Uncovered temporary or guest parking on private residential lots may be: paved with a permeable surface; or, designed to drain into landscaping prior to discharging to the storm water conveyance system. 6.C. Other features which are comparable and equally effective. 7. Dock Areas X Loading/unloading dock areas shall include the following. 7.a. Cover loading dock areas, or design drainage to preclude urban run-on and runoff 7.b. Direct connections to storm drains from depressed loading docks (truck wells) are prohibited. 7.C. Other features which are comparable and equally effective. 8. Maintenance Bays X Maintenance bays shall include the following. 8.a. Repair/maintenance bays shall be indoors; or, designed to preclude urban run-on and runoff. 8.b Design a repair/maintenance bay drainage system to capture all wash water, leaks and spills. Connect drains to a sump for collection and disposal. Direct cormection of the repair/maintenance bays to the storm drain system is prohibited. If required by local jurisdiction, obtain an Industrial Waste Discharge Permit. 8.C. Other features which are comparable; and equally effective. 9. Vehicle Wash Areas X 9.a. Self-contained; or covered with a roof or overhang. 9.b Equipped with a clarifier or other pr^freatment facility. 9.C. Properly connected to a sanitary sewpr. 9.d. Other features which are comparable! and equally effective. 12 BMP YES NO N/A 10. Outdoor Processing Areas X Outdoor process equipment operations, such as rock grindmg or crushing, painting or coating, grinding or sanding, degreasing or parts cleaning, waste piles, and wastewater and solid waste treatment and disposal, and other operations determined to be a potential threat to water quality by the County shall adhere to the following requirements. lO.a. Cover or enclose areas that would be the most significant source of pollutants; or, slope the area toward a dead*end sump; or, discharge to the sanitary sewer system following appropriate treatment in accordance with conditions established by the applicable sewer agency. lO.b. Grade or berm area to prevent run-on fi-om isurroimding areas. lO.c. Installation of storm drains in areas of equipment repair is prohibited. lO.d. Other features which are comparable or equally effective. 11. Equipment Wash Areas X Outdoor equipment/accessory washing and steam cleaning activities shall be. I l.a. Be self-contained; or covered with a roof or overhang. 11.b. Be equipped with a clarifier, grease trap or other pretreatment facility, as appropriate ll.C. Be properly connected to a sanitary sewer. 11.d. Other features which are comparable or eqtially effective. 12. Parking Areas X The following design concepts shall be considered, and incorporated and implemented where determined applicable and feasiible by the County. 12.a. Where landscaping is proposed in parking areas, incorporate landscape areas into the drainage design. 12.b. Overflow parking (parkmg stalls provide in excess of the County's minimum parking requirements) may be coiistructed with permeable pavmg. 12.C. Other design concepts that are comparable ^and equally effective. 13. Fueling Area X Non-retail fuel dispensing areas shall contain the fallowing. 13.a. Overhanging roof structure or canopy. The;tover's minimum dimension must be equal to or greater thanitihe area within the grade break. The cover must not drain onto the fUel dispensing area and the dovraspout must be routed to prevent drainage across the fueling area. The fueling area shall drain to the project's: treatment control BMP(s) prior to discharging to the storm water conveyance system. 13.b. Paved with Portland cement concrete (or equivalent smooth impervious surface). The use of asphalt concrete shall be prohibited. 13.C. Have an appropriate slope to prevent ponding, and must be separated from the rest of the site by grade break that prevents run-on of urban runoff 13 BMP YES NO N/A 13.d. At a minimum, the concrete fiiel dispensing area must extend 6.5 feet (2.0 meters) from the comer of each fiiel dispenser, or the length at which the hose and nozzle assembly may be operated plus I foot (0.3 meter), whichever is less. X Please list other project specific Source Control BMPs in the following box. Write N/A if there are none. 14 TREATMENT CONTROL To select a stmctural treatment BMP using Treatment Control BMP Selection Matrix (Table 10), each priority project shall compare the list of pollutants for which the downstream receiving waters are impaired (if any), with the pollutants anticipated to be generated by the project (as identified in Table 4). Any pollutants identified by Table 4, which are also causing a Clean Water Act section 303(d) impairment of the receiving waters of the project, shall be considered primary pollutants of concem. Priority projects that are anticipated to generate a primary pollutant of concem shall select a single or combination of stormwater BMPs from Table 10, which maximizes pollutant removal for the particular prunary pollutant(s) of concem. Priority development projects that are not anticipated to generate a pollutant for which the receiving water is CWA 303(d) unpafred shall select a smgle or combination of stormwater BMPs from Table 10, which are effective for pollutant removal of the identified secondary pollutants of concem, consistent with the "maximum extent practicable" standard. Table 10. Treatment Control BMP Selection Matrix Pollutants of Concern Bioretention Facilities (LED)* Settling Basins (Dry Ponds) Wet Ponds And Wetlands Infiltration Facilities or Practices (LID)* Media Filters High-rate biofiiters High-rate Media fllters Trash Racks & Hydro -dynamic Devices Coarse Sediment and Trash High High High High High High High High Pollutants that tend to associate with fine particles during treatment High High High High High Medium Medium Low Pollutants that tend to be dissolved following treatment Medium Low Medium Higli Low Low Low Low 'Additional information is available in the County of San Diego LID Handbook. 15 NOTES ON POLLUTANTS OF CONCERN: In Table 11, Pollutants of Concem are grouped as gross pollutants, pollutants that tend to associate with fine particles, and pollutants that remain dissolved. Table 11 Pollutant Coarse Sediment and Trash Pollutants that tend to associate with fme particles during treatment Pollutants that tend to be dissolved following treatment Sediment X X X Nutrients X X Heavy Metals X Organic Compounds X Trash & Debris X Oxygen Demanding X Bacteria X Oil & Grease X Pesticides X c A Treatment BMP must address runoff from developed areas. Please provide the post- construction water quality treatment volume or flow values for the selected project Treatment BMP(s). Guidelines for design calculations are located in Chapter 5, Section 4.3, Principle 8 of tiie County SUSMP. Label outfalls on the BMP map. The Water Quality peak rate of discharge flow (QWQ) and the; Water Quality storage volume (VWQ) is dependent on the type of freatment BMP selected;|br the project. SEE ATTACHED FOR HYDRALUC CALCULATIONS 16 Please check fhe box(s) that best describes the Treatment BMP(s) selected for this project. Biofiiters • Bioretention swale X Vegetated filter strip • Stormwater Planter Box (open-bottomed) • Stormwater Flow-Through Planter (sealed bottorti) • Bioretention Area • Vegetated Roofs/Modules/Walls Detention Basins X Extended/dry detention basin with grass/vegetated lining • Extended/dry detention basin with impervious lining Inflltration Basins • Infiltration basin • Inflltration trench • Dry well • Permeable Paving • Gravel • Permeable asphalt • Pervious concrete • Unit paver, ungrouted, set on sand or gravel • Subsurface reservoir bed Wet Pounds or Wetlands • Wet pond/basin (permanent pool) • Constructed wetland Filtration • Media flltration • Sand filtration Hydrodynamic Separator Systems X Swirl Concentrator • Cyclone Separator Trash Racks and Screens Include Treatment Datasheet as Attachment D. The datasheet Should include the following: COMPLETED NO 1. Description of how treatment BMP was designed. Provide a Description for each type of treatment BMP. , X 2. Engineering calculations for the BMP(s) SEE ATTACHEMENTD 17 Please describe why the selected freatment BMP(s) VKfis selected for this project. For projects utilizing a low performing BMP, please provide a detailed explanation. The selected BMP's (bio-swale, bio-filtration/detention, hydro-dynamic separator) have been selected for the reason that they blend naturally to the proposed layout of the project without having to do any modification to the drainage pattems or disturbing any additional area at the site. CONCLUSION: The combination of proposed construction and post-construction BMP's will reduce, to the maximum extent practicable, the expected poUut^ints and will not adversely impact beneficial uses or water quality of the receiving vi'aters. MAINTENANCE Please check the box that best describes the maintensifrce mechanism(s) for this project. Guidelines for each category are located in Chapter 5;, Section 5.2 of the County SUSMP. CATEGORY SELECTED CATEGORY YES NO First Second X Third ^ Fourth Note: 1. Projects in Category 2 or 3 may choose to establish or be included in a Stormwater Maintenance Assessment District for the long-term maintenance of freatment BMP's. ATTACHMENTS 'lease include the following attachments. ATTACHMENT COMPLETED N/A A Project Location Map/ Site Map X Relevant Monitoring Data X B LID and Treatment BMP Location Map X C Treatment BMP Datasheets/Hydraulics/Operation and Maintenace Program for BMP's X Fiscal Resources X D Certification Sheet X Addendum X 18 G.'avel Pit'' —w'/^v^^ • Sintorosa .Country Club ''•.it ' // IS Point S !J \ \\ < /V AC^; y --4-/ < •--y / ^ T:° I I I 1000 Primed frcm TC?C' %• 1 y?*" Wildflcwei- ?rcdu:ticns (\\-wvv.topc.:cir.' Maiidatia Cai Cp A']RtA5 Grosse 17.1 28 Hagaman 5.2 15 Coman 9.5? ATTACHMENT A PROJECT LOCATION MAP 19 a VISTA VICINITY MAP NO SCALE ATTACHMENT B LID AND TREATMENT BMP LOCATION MAP 20 ATTACHMENT C TREATMENT BMP DATASHEETS/HYDRAULICS/OPERATION AND MAINTENANCE PROGRAM FOR BMP'S 21 RANCH MILAGRO JN 1674 Treatment Control BMP Flow based BMPs shall be desinged to mitigate the maximum flow rate of runoff produced from a rainfall intensity of 0.2 inch of rairrfail per hour for each hour of a storm event Q = CIA I = 0.2 INflHR Low Density Residential C = 0.41 LOT NO. PAD AREA (AC) Q(CFS) 4 0.34 0.028 5 0.35 0.029 6 0.27 0.022 7 0.28 0.023 8 0.34 0.028 10 0.33 0.027 11 0.30 0.025 12 0.32 0.026 13 0.44 0.036 2/' *S>^t^Pcec i2>io Sev Acer Cfi-oi'O'-} channel Calculator Given Input Data: shape Trapezoidal Solving for Depth of Flow Flowrate 0.0150 cfs Slope 0.0100 ft/ft Manning's n 0.2500 Height 10.0000 in Bottom width 0.0000 in Left slope 0.3333 ft/ft (V/H) Right slope 0.3333 ft/ft (V/H) Computed Results: Depth 2.4098 in , velocity 0.1240 fps L - SZ. c Imtt^. CoWTncr 7?/^*- Full Flowrate 0.6670 cfs Flow area . 0 1210 ft2 Cbi^P^ Neiu Oe^tftoPf^-J- Flow penmeter 15.2421 in ^ ' Hydraulic radius 1.1431 in , , ^ ... Top width 14.4601 in H^f>/t> ©ooM >T^75^ Lirrur Area 2.0835 ft2 _ Perimeter 63.2512 in UiF-P^icerstce ^eflwencn lo tn^n. •€ Percent full 24.0977 % CL ^ Critical information o critical depth 0.8269 in ^'^'^^'^ ^fi^-n^ertB^ Critical slope 3.0021 ft/ft Critical velocity 1.0529 fps Tuic — y. ^ ^ Critical area 0.0142 ft2 ^c^Acff L«n<<^ C^H Critical perimeter 5.2303 in a^s^ , i ^ "7C' Critical hydraulic radius 0.3922 in e/te^cy tte IN.Ctie:i'ViJS:K> TO Critical top width 4.9619 in Specific energy 0.2011 ft To- p/Zov/oc- /€> mtn. CaACTT^CT- Minimum energy 0.1034 ft Froude number p-P^^?.. TtM^. Th* ^ CA H Bo-/ ^fic£M7m Flow condition Subcritical >r'»<=r. r f^-rv 2. tCsePTvi t 2.4" Page 1 Vegetated Swale TC-30 The topography ofthe site should permit fhe design of a channel vnth. appropriate slope and cross-sectional area. Site topography may also dictate a need for additional structural confrols. Recommendations for longitudinal slopes range between 2 and 6 percent. Flattei' 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 using a series of check dams to terrace the swale and reduce fhe slope to within acceptable Hmits. The use of check dams witii swales also promotes infiltration. Additionai Design Guidelines Most of fhe design guidehnes adopted for swale design specify a ininimum hydrauhc residence time of 9 minutes. This criterion is based on the results of a single study conducted in Seattie, Washington (Seattle Mefro and Washington Department of Ecology, 1992), and is not well supported. Analysis of the data collected in that study indicates that pollutant removal at a residence time of 5 minutes was not significantiy different, although there is more variabihty in that data. Therefore, additional research in fhe design criteria for swales is needed. Substantial pollutant removal has also been observed for vegetated controls designed solely for conveyance (Barrett et al, 1998); consequentiy, some flexibihty in the design is warranted. Many design guidehnes recommend that grass be frequentiy mowed to maintain dense coverage near fhe ground surface. Recent research (Colwell et al., 2000) has shown mowing frequency or grass height has Htfle or no effect on pollutant removal. Summary of Design Recommendations 1) The swale should have a length that provides a minimum hydrauhc residence time of at least 10 minutes. The maximum bottom width should not exceed 10 feet unless a dividing berm is provided. The depth of flow should not exceed 2/3rds llie height of the grass at the peak of fhe water quahty design storm intensity. The channel slope shoiild not 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 than 100 feet in lengtii. 4) The width of fhe 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 facOity for fhe design storm and as a conveyance system to pass fhe peak hydraulic flows of fhe 100-year storm if it is located "on-hne." The side slopes shouldbe no steeper fhan 3:1 (H:V). 6) Roadside ditches shoiild be regarded as significant potential swale/buffer strip sites and should be utihzed for this purpose whenever possible. If flow is to be introduced through curb cuts, place pavement shghtiy above fhe elevation of fhe vegetated areas. Curb cuts should be at least 12 hiches wide to prevent cloggiag. 7) Swales must be vegetated in order to provide adequate freatment of runoff. It is important to maximize water contact with vegetation and fhe soil surface. For general purposes, select fine, close-growing, water-resistant grasses. If possible, divert runoff (other fhan necessary frrigation) during the period of vegetation January 2003 California Stormwater BMP Handbook 5 of 13 New Development and Redevelopment www.cabmphandbooks. com RANCHO MILAGRO JN 1674 LOTNO. 1 PAD(SF) | PAD (AC) | GROSS AREA (AC) 1 14670 0.34 0.554 2 10275 0.24 0.551 3 14644 0.34 0.56 9 19094 0.44 0.5 14 19382 0.44 0.529 15 17069 0.39 0.541 16 12778 0.29 0.511 17 13119 0.30 0.556 18 15941 0.37 0.524 19 12860 0.30 0.525 20 13911 0.32 0.56 21 13618 0.31 0.31 BY LOT 20 0.58 0.58 BY LOT 1 1.20 2.40 177,361.00 5.85 9.2 STREET 3.2 i2A TOTAL PAD = 5.85 AC 15% PERVIOUS IMPERVIOUS PAD = 5.0 AC STREET AREA = 3.2 AC TOTAL IMPERVIOUS AREA = 8.2 TOTAL % IMPERVIOUS = 66% LoT^ TT^inkT Ojz.0^t.t-J To 71*6' ^/Tt^sffT ^ •^•ma.*^ OfZ«^tt^t Ptf»e^ AfuO TVinx><j>c ^ '7~H<sr S'rT>a.f^ c^erprve^ /^A*t> /A*7-» TV*<F /3<O - Ocrrs?xvi«AV THtSi ft«o-c?e71F>*rio/v e^ts^/v/ //odos /6, Cf/io Ca. rp4^- <r^ Srhttf^ (xi^retL /5«r)=bc<3- e^jeic^'-^a, s-ns/t/.^ /«^«t/s TO AC^OA, stormceptor CD Sizing Program United States Version 4.0.0 Project Details Project RANCHO MILAGRO Project # 1674 Location CARLSBAD Company MANrrOU ENGINEERING Date 05/25/07 Contact Selected Rainfall Station state Califbmia Name ESCONDIDO CHURCH RANCH 10 # 2871 Elev. (ft) 722 Latitude N 33 deg 6 min Longitude W117 deg 5 min Site Parameters Total Area (ac) 12.4 Imperviousness (%) 66 Impervious Area (ac) 8.18 Particle Size Distribution Diam. (um) Percent (%) Spea Gravity 20 20 1.30 60 20 1.80 150 20 2.20 400 20 2.65 2000 20 2.6S Stonnceptor Sizing Table Stormceptor Model % Runoff Treated % TSS Removal STC 450 34 51 STC 900 50 62 STC 1200 50 62 STC 1800 50 62 STC 2400 61 68 STC 3600 61 69 STC 4800 73 74 STC 6000 73 74 STC 7200 80 78 STC 11000 87 82 STC 13000 87 83 STC 16000 92 85 -Ofmentor CD Sizing Program Version 4.0.0 "Country United States Date 05/25/07 Pnoject Number Project Name Project Location Company Designer Notes Rainfall Station Rainfell File Latitude = Longitude = Eievation = Rainfell Period of Record 1674 RANCHO MILAGRO CARLSBAD MANITOU ENGINEERING ESCONDIDO CHURCH RANCH CA2871.NDC N 33 deg 6 min W 117 deg 5 min 722. ft 1948 to 1958 Site Parameters Total Orainage Area 12.40 ac Totel imperviousness (%) 66.00 "*veriand Fiow Width 1470. ft V^/erland Slope (%) 2.0 ^.npervious Depression Storage 0.020 in Pervious Depression Storage 0.200 in Impen/ious Mannings n 0.015 Pennous Mannings n 0.250 Infiltration Parameters Horton Infiltration Used initial (Max) Infiltration Rate Final (MIn) infiltration Rate Inflltration Decay Rate (1/sec) 2.44 in/h 0.40 in/h 0.00055 Infiltration Regeneration Rate (1/sec) 0.010 Daily evaporation 0.100 in/day Sediment build-up reduces the storage volume for settiing calculations A maintenance cycle of 12 montiis was chosen (The Stormceptor will be cleaned out every 12 months) 3 Loading Calculations 'Buildup / Washoff Loading Chosen Buildup Washoff allocates more washoff in the rising limb of the hydrograph Target Event Mean Concentration (mg/l) 125. Buildup Exponent 0.400 Washoff Exponent 0.200 AvaiiatMlity Factors for Particles >= 400. um Availability = A + Bi'H:; A = 0.057 B = 0.040 i = rainfell intensity C= 1.100 Stomiwater Particle Size Distribution Table Diameter Percent Specific Gravity Settiing Velocity (um) (%) ft/s 20.0 20.0 1.30 0.0013 60.0 20.0 1.80 0.0051 150.0 20.0 2.20 0.0354 400.0 20.0 2.65 0.2123 2000.0 20.0 2.66 0.9417 v...,occulated settiing assumed for particles <= 20 um Rainfall records 1948 to 1958 Total rainfall period 11 years Totel rainfall = 125.4 in Average annual rainfall = 11.4 in ^ infall event analysis 2.0 hour inter event time used to detennine # of events < in Events % Vol in % 0.25 480 77.5 29. 23.4 0.50 61 9.9 22. 17.3 0.75 35 5.7 21. 16.9 1.00 22 3.6 19. 15.5 1.25 7 1.1 8. 6.5 1.50 6 1.0 8. 6.4 1.75 2 0.3 3. 2.5 2.00 1 0.2 2. 1.6 2.25 3 0.5 6. 5.1 2.50 0 0.0 0. 0.0 2.75 1 0.2 3. 2.1 3.00 0 0.0 0. 0.0 3.25 0 0.0 0. 0.0 3.50 1 0.2 3. 2.8 3.75 0 0.0 0. 0.0 4.00 0 0.0 0. 0.0 4.25 0 0.0 0. 0.0 4.50 0 0.0 0. 0.0 4.75 0 0.0 0. 0.0 5.00 0 0.0 0. 0.0 5.25 0 0.0 0. 0.0 5.50 0 0.0 0. 0.0 5.75 0 0.0 0. 0.0 "wO.OO 0 0.0 0. 0.0 6.25 0 0.0 0. 0.0 6.50 0 0.0 0. 0.0 6.75 0 0.0 0. 0.0 7.00 0 0.0 0. 0.0 7.25 0 0.0 0. 0.0 7.50 0 0.0 0. 0.0 7.75 0 0.0 0. 0.0 8.00 0 0.0 0. 0.0 8.25 0 0.0 0. 0.0 > 8.25 0 0.0 0. 0.0 Total rain 125. in Number of rain events 619 nfall intensity analysis Average intensity = 0.21 in/h < in/h Number % Vol in % 0.25 1853 76.3 43. 34.0 0.50 311 12.8 28. 22.3 0.75 137 5.6 21. 16.4 1.00 77 3.2 17. 13.2 1.25 19 0.8 5. 4.2 1.50 18 0.7 6. 4.9 1.75 5 0.2 2. 1.6 2.00 5 0.2 2. 1.9 2.25 1 0.0 1. 0.4 2.50 1 0.0 1. 0.5 2.75 0 0.0 0. 0.0 3.00 1 0.0 1. 0.6 3.25 0 0.0 0. 0.0 3.50 0 0.0 0. 0.0 3.75 0 0.0 0. 0.0 4.00 0 0.0 0. 0.0 4.25 0 0.0 0. 0.0 4.50 0 0.0 0. 0.0 4.75 0 0.0 0. 0.0 5.00 0 0.0 0. 0.0 5.25 0 0.0 0. 0.0 5.50 0 0.0 0. 0.0 5.75 0 0.0 0. 0.0 ^•i^^ 6.00 0 0.0 0. 0.0 6.25 0 0.0 0. 0.0 6.50 0 0.0 0. 0.0 6.75 0 0.0 0. 0.0 7.00 0 0.0 0. 0.0 7.25 0 0.0 0. 0.0 7.50 0 0.0 0. 0.0 7.75 0 0.0 0. 0.0 8.00 0 0.0 0. 0.0 8.25 0 0.0 0. 0.0 > 8.25 0 0.0 0. 0.0 Totel rainfall = 125.4 in Tofal evaporation = 10.3 in Totel infittiBtion = 42.6 in % Rainfall as ainoff = 59.0 % Average Event Mean Concentration for TSS (mg/l) 79.6 V. 3 RenK>val Simulation Results Table Stormceptor Treated Q % Runoff Tank TSS Overaii TSS Model cfs Treated Removal (%) Removal (%) STC 450 0.283 34. 71. 51. STC 900 0.636 60. 75. 62. STC 1200 0.636 50. 76. 62. STC 1800 0.636 50. 76. 62. STC 2400 1.059 61. 78. 68. STC 3600 1.059 61. 78. 69. STC 4800 1.766 73. 80. 74. STC 6000 1.766 73. 80. 74. STC 7200 2.472 80. 82. 78. STC 11000 3.631 87. 86. 82- STC 13000 3.531 87. 85. 83. STC16000 4.944 92. 86. 85. Hydrology Table - Volunrie of Runoff Treated vs By-Pass Flow Rate Tieated Q Treated Vol Over Vol Tot Vol % Treated cfs fl3 fts fl3 0.035 269998. 3061392. 3331389. 8.1 0.141 752951. 2578444. 3331389. 22.6 L X318 1194348. 2137058. 3331389. 35.9 ^0.565 1578452. 1752940. 3331389. 47.4 0.883 1906452. 1424926. 3331389. 67.2 1.271 2183399. 1147974. 3331389. 65.5 1.730 2416752. 914623. 3331389. 72.5 2.260 2611458. 719905. 3331389. 78.4 2.860 2770729. 560651. 3331389. 83.2 3.531 2900111. 431263. 3331389. 87.1 4.273 3004461. 326929. 3331389. 90.2 5.085 3086981. 244399. 3331389. 92.7 5.968 3151838. 179547. 3331389. 94.6 6.922 3200715. 130669. 3331389. 96.1 7.946 3237166. 94221, 3331389. 97.2 9.041 3264930. 66457. 3331389. 98.0 10.206 3286381. 45011. 3331389. 98.6 11.442 3300661. 30729. 3331389. 99.1 12.749 3309843. 21548. 3331389. 99.4 14.126 3317090. 14300. 3331389. 99.6 15.574 3321984. 9407. 3331389. 99.7 17.092 3325185. 6205. 3331389. 99.8 18.681 3327166. 4222. 3331389. 99.9 20.341 3328299. 3090. 3331389. 99.9 22.072 3329337. 2062. 3331389. 99.9 23.873 3330418. 971. 3331389. 100.0 25.744 3331027. 362. 3331389. 100.0 27.687 3331389. 0. 3331389. 100.0 29.700 3331389. 0. 3331389. 100.0 31.783 3331389. 0. 3331389. 100.0 End of Simulation for hydrograph ?S_ in. 2.a DETENTION STORAGB COMPUTATION PROCEDURE SINGLE HYDROGRAPH FORM Input Variables (Urban ConditionsV Six hour precipitation amount (inches) Pj Time Of concentration (min.) '7- 5 Coefficient of runoff C 0-4-1 Basin area (acres) A lZ-4t Computation Time to peak c? 2 Tp = 2.0T^D/(1 + Kp) = 1.1072T, Tp Time of hydrograph to begin TB = 20 - Tp TB _/XL_Z Time of hydrograph to end 'z.r, ytti TB = 20 + 1.5 Tp ,^2^:32. Peak flow . o-^ Qp = .CIA ere. ZB-2>a IT, = 7.44 P5/T.°'«* = K>.C^ in./hr. Surrounding flow (Qs) Depth of precipitation for 2 hours D,2o = 7.44 P5/120°"^(2 hr.) Dj2o = 0.6785 P« / 9 in. Depth of precipitation D„ = (P<T/'")/5.S3 = _Oi Surrounding Intensity I3 =. 60(Dijo - D„)/(120 - 2.5TJ Is = OS4- in./hr. Qs = CIsA Qs ?-74_ Plot Hydrograph and Surrounding Flow Outflow / Basin Size (NaTAiral Conditions) Outflow C = 0 3S T = 1 min. I = 7.44 Pfi/T,°«* = ^ 4:? in./hr. QK = CIA QN /-^Q 1. Plot on Hydrograph a. Draw line from surrounding flow intercept with beginning hydrograph limto to Q„ 2. Estimate volumie needed for reservoir a. Determine preliminary reservoir dimensions b. Surrounding flow discharges directly through reservoir without detaining any storage 3. Size outlet works £ a. Outlet flow, less than or equal to Qjj b. Stay within the limits of the reservoir 4. Rout a. Refine reservoir dimensions and/or outflow facility A. V) u. v] 3o- 5 - 0 Qp'- 28.9 CFS \/ ^I6.^. Fry 7-0 5C? ^ MO ^ ' 32-US nifJ Extended Detention Basin TC-22 Design Considerations • Tnbutary Area • Area Required • Hydraulc Head Description Diy extended detenticHi ponds (aJk.a. dry ponds, extended detention basins, detention ponds, extended detention ponds) are basuis whose outlets have been designed to detain the stnrmwater runoff from a water quahty design storm for some minimum time (e.g., 48 hours) to allow particles and associated pollutants to settle. Unhke wet ponds, these faciHties do not have a large permanent pool. They can also be used to provide flood control by including additional flood detention storage. Califomia Experience Caltrans constructed and monitored 5 extended detention basins in southem Califomia with design drain times of 72 hours. Four of the basins were earthen, less costiy and had substantially better load reduction because of infiltration that occurred, than the concrete basin. The Caltrans study reaffirmed the flexibihty and performance of this conventional technology. The small heacfloss and few siting constraints suggest that these devices are one of the most apj^cable technologies for stormwater treatmmt Advantages • Due to the simpiicity of design, extended detention basins are relatively easy and inexpensive to ccnstruct and operate. • Extended detention baans can provide substantial capture of sediment and tiae toxics fraction assodated with particulates. • Widespread application with suffident capture volume can provide significant control of channel erosion and enlargement caused by changes to flow frequency Targeted Constituents Sediment • m lijtnents • El Trash • El Metals Sl Baciena • El Oil and Grease • El Oganics . A Legend (RemovalBfhetiverm^ • Low • High A Medium January 2003 California Stonnwater BMP Handbook New Development ard Redevelopment w WW. cabrriphancbook, com 1 of 10 TC-22 Extended Detention Basin relationships resulting from the increase of impervious cover in a watershed. Limitations • Limitation of the diameter of the orifice may not allow use of extended detention in watersheds of less than 5 acres (would require an orifice with a diameter of less than 0.5 inches that would be prone to clogging). • Dry extended detention ponds have only moderate poUutant removal when compared to some other structural stormwater practices, and they are relatively ineffective at removing soluble pollutants. • Although wet ponds can increase property values, diy ponds can actually detract from fhe value of a home due to the adverse aesthetics of dry, bare areas and inlet and outiet structures. Design and Sizing Guidelines • Capture volume determined by local requirements or sized to treat 85% of the annual runoff volume. • Outiet designed to discharge the capture volume over a period of hours. • Length to width ratio of at least 1.5:1 where feasible. • Basin depths optimally range from 2 to 5 feet. • Include energy dissipation in the inlet design to reduce resuspension of accumulated sediment • A maintenance ramp and perimeter access should b e included in the design to f acihtate access to the basin for matntenance activities and for vector surveillance and control. • Use a draw down time of 48 hours in most areas of Califomia. Draw down times in excess of 48 hours may result in vector breeding, and should be used only after coordination with local vector control authorities. Draw down times of less than 48 hours should be Umited to BMP drainage areas with coarse soUs that readUy setde and to watersheds where warming may be determined to downstream fisheries. Construction/Inspection Considerations • Inspect faciUty after first large to storm to determine whether the desired residence time has been achieved. • When constmcted with smaU tributary area, orifice sizing is critical and inspection should verify that flow through additional opermigs such as bolt holes does not occur. Performance One objective of stormwater management practices can be to reduce the flood hazard associated with large storm events by reducing the peak flow associated with these storms. Dry extended detention basins can easily be designed for flood control, and this is actuaUy the primaiy purpose of most detention ponds, 2 of 10 Califbrnia stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Extended Detention Basin TC-22 Dry extended detention basins provide moderate poUutant removal, provided that the recommended design features are incorporated. Although they can be effective at removing some poUutants through settUng, they are less effective at removing soluble poUutants because of the absence of a permanent pool. Several studies are avaUable on the effectiveness of dry extended detentionponds including one recentiy concluded by Caltrans (2002). The load reduction is greater than the concentration reduction because of the substantial infiltration that occurs. Although the infiltration of stormwater is dearly beneficial to surface receiving waters, there is the potential for groundwater contamination. Previous research on the effects of incidental infiltration on groundwater quaUty indicated that the risk of contamination is minimal. There were substantial differences in the amount of infiltration that were observed in the earthen basins during the Caltrans study. On average, approximately 40 percent of the runoff entering the unUned b asins infiltrated and was not discharged. The percentage ranged from a high of about 60 percent to a low of only about 8 percent for the different fadUties. CUmatic conditions and local water table elevation are Ukely the principal causes of this difference. The least infiltration occurred at a site located on the coast where humidity is higher and the basin invert is within a few meters of sea level. Conversely, the most infiltration occurred at a facUity located weU inland in Los Angeles County where the cUmate is much warmer and the humidity is less, resulting in lower soU moisture contentin the basin floor at the beginning of storms. Vegetated detention basins appear to have greater poUutant removal than concrete basins. In the Caltrans study, the concrete basin exported sediment and associated poUutants during a number of storms. Export was not as common in the earthen bashis, where the vegetation appeared to help stabUize the retained sediment. Siting Criteria Dry extended detention ponds are among the most widely appUcable stormwater management practices and are espedaUy useful in retrofit situations where their low hydrauUc head requirements aUow them to b e sited within the constraints of the existing storm drain system. In addition, many commimities have detention basins designed for flood control. It is possible to modify these fadUties to incorporate features that provide water quaUty treatment and/or channel protection. Although dry extended detention ponds can be appUed rather broadly, designers need to ensure that they are feasible at the site in question. This section provides basic guideUnes for siting dry extended detention ponds. In general, dry extended detention ponds shoiUd be used on sites with a minimum area of 5 acres. With this size catchment area, the orifice size can be on the order of 0.5 inches. On smaUer sites, it can be chaUenging to provide channel or water quaUty control because the orifice diameter at the outiet needed to control relatively smaU storms becomes very smaU and thus prone to dogging. In addition, it is generaUy more cost-effective to control larger drainage areas due to the economies of scale. Extended detention basins can be used with almost aU soils and geology, with minor design adjustments for regions of rapidly percolating soUs such as sand. In these areas, extended detention ponds may need an impermeable Uner to prevent ground water contamination. January 2003 California Stormwater BMP Handbook 3 of 10 New Development and Redevelopment www.cabmphandbook.com c TC-22 Extended Detention Basin The base of the extended detention fadUty should not intersect the water table. A permanentiy wet bottom may become a mosquito breeding ground. Research in Southwest Florida (Santana et al., 1994) demonstrated that intermittentiy flooded systems, such as dry extended detention ponds, produce more mosquitoes than other pond systems, particularly when the facUities remained wet for more than 3 days foUowing heavy rainfaU. A study hi Prince George's Coimty, Maryland, found that stormwater management practices can increase stream temperatures (Galli, 1990). OveraU, dry extended detention ponds increased temperature by about 5"F. In cold water streams, dry ponds should be designed to detain stormwater for a relatively short time (i.e., 24 hours) to minimize the amount of warming that occurs in the basin. Additional Design Guidelines In order to enhance the effectiveness of extended detention basins, the dimensions ofthe basUi must be sized appropriately. Merely pro\iding the required storage volume wUl not ensure maximum constituent removal. By effectively configuring the basin, the designer wiU create a long flow path, promote the estabUshment of low vdodties, and avoid having stagnant areas of the basin. To promote settiing and to attain an appealing environment, the design of the basin should consider the length to width ratio, cross-sectional areas, b asin slopes and pond configuration, and aesthetics (Young et al., 1996). Energy dissipation structures should be induded for the basin inlet to prevent resuspension of accumulated sediment. The use of stiUing basins for this purpose should be avoided because the standing water provides a breeding area for mosquitoes. Extended detention fadlities shouldbe sized to completdy capture the water quaUty volume. A micropool is often recommended for indusion in the design and one is shown in the schematic diagram. These smaU permanent pools greatiy increase the potential for mosquito breeding and compUcate maintenance activities; consequentiy, they are not recommended for use in CaUfomia. A large aspect ratio may improve the performance of detention basins; consequentiy, the outiets shoiUd be placed to maximize fhe flowpath through the fadUty. The ratio of flowpath length to width from the inlet to fhe outiet should be at least 1.5:1 (L:W) where feasible. Basin depths optimally range from 2 to 5 feet. The facUity's drawdown time should be regulated by an orifice or weir. In general, the outflow stmcture should liave a trash rack or other acceptable means of preventing dogging at the entrance to tiie outflow pipes. The outiet design implemented by Caltirans in tiie fadUties constmcted in San Diego County used an outiet riser wtih orifices Figure 1 Example of Extended Detention Outiet Structure 4 of 10 Californja Stormwater BMP Handbook New Development and Redevelopment WW w, cabmphandbooks ,com January 2003 Extended Detention Basin TC-22 sized to discharge the water quaUty volume, and the riser overflow hdght was set to the design storm devation. A stainless sted screen was placed around the outiet riser to ensure thatthe orifices would not become dogged with debris. Sites dther used a separate riser or broad crested weir for overflow of runoff for the 25 and greater year storms. Apicture of a typical outiet is presented in Figure 1. The outflow stmcture should be sized to aUow for complete drawdown of the water quaUty volume in 72 hours. No more than 50% of the water quality volume shoiUd drain from the fadlity within the first 24 hours. The outflow stmcture can be fitted with a valve so that dischaige from the basin can be halted in case of an acddental spiU in fhe watershed. Summary of Design Recommendations (1) FacUity Sizing - The required water quaUty volume is determined by local regulations or the basin should be sized to capture and treat 85% of the annual runoff volume. See Section 5.5.1 of the handbook for a discussion of volume-based design. Basin Configuration - A high aspect ratio may improve the performance of detention basins; consequentiy, the outiets shoidd be placed to maximize the flowpath through the faciUty. The ratio of flowpath length to width from the inlet to the outiet should be at least 1.5:1 (L: W). The flowpath length is defined as the distance from the inlet to the outiet as measured at the surface. The width is defined as the mean width of the basin. Basin depths optimaUy range from 2 to 5 feet. The basin may indude a sediment forebay to provide the opportunity for larger partides to settie out. \^ A micropool should not be incorporated in fhe design because of vector concems. For oiUine facUities, the prindpal and emergency spiUways must be sized to provide 1.0 foot of freeboard during the 25-year event and to safely pass the flow from loo-year storm. (2) Pond Side Slopes - Side slopes of the pond shoiUdbe 3:1 (H:V) or flatter for grass StabUized slopes. Slopes steeper than 3:1 (H; V) must be stabUized with an appropriate slope stabiUzation practice. (3) Bastn Lining - Basins must be constmcted to prevent possible contamination of groundwater below the faciUty. (4) Basin Inlet - Energy dissipation is required at the basin inlet to reduce resuspension of accumulated sediment and to reduce the tendency for short-circuiting. (5) Outflow Stmcture - The fadUt^s drawdown time should be regulated by a gate valve or orifice plate. In general, the outflow stmcture should have a trash rack or other acceptable means of preventing dogging at the entrance to the outflow pipes. The outflow stmcture should be sized to aUow for complete drawdown of the water quaUty volume in 72 hours. No more than 50% of the water quality volume shoiUd drain from the facUity within the first 24 hours. The outflow stmcture should be fitted with a valve so that discharge from the basin can be halted in case of an acddental spUl in the watershed. This same valve also can be used to regulate fhe rate of discharge from the basin. January 2003 California Stormwater BMP Handbook 5 of 10 New Development and Redevelopment www.cabmphandbook. com TC-22 Extended Detention Basin The discharge tiirough a control orifice is calculated from: Q = CA(2gH-Ho)°s where: Q = dischaige (ft3/s) C = orifice coeffident A area ofthe orifice (ft^) g = gravitational constant (32.2) H = water surface elevation (ft) Ho= orifice devation (ft) Recommended values for C are 0.66 for thin materials and 0.80 when the material is thicker than the orifice diameter. This equation can be implemented in spreadsheet form with the pond stage/volume rdationship to calctUate drain time. To do this, use the initial hei^t of the water above fhe orifice for fhe water quaUty volume. Calculate the discharge and assume that it remains constant for approximatdy 10 minutes. Based on that discharge, estimate the total discharge during that interval andthe new devation based on the stage volume rdationship. Continue to iterate until H is approximately equal to Ho. When using multiple orifices the discharge from each is summed. (6) SpUtter Box - When the pond is designed as an offline fadUty, a spUtter stmcture is used to isolate the water quaUty volume. The spUtter box, or other flow diverting approach, shouldbe designed to convey the 25-year storm event while providing at least 1.0 foot of freeboard along pond side slopes. (7) Erosion Protection at the OutfaU - For onUne facUities, special consideration should be given to the fadlity's outfaU location. Flared pipe end sections that discharge at or near the stream invert are preferred. The channd immediately below the pond outfaU should be modified to conform to natural dimensions, and Uned with large stone riprap placed over filter cloth. Energy dissipation may be required to reduce flow velocities from the primary spiUway to non-erosive velodties. (8) Safety Considerations - Safety is provided either by fencing of fhe fadUty or by managing the contours of fhe pond to ehminate dropoffs and other hazards. Earthen side slopes should not exceed 3:1 (H: V) and should terminate on a flat safety bench area. Landscaping can be used to impede access to the fadUty. The primary spUlway opening must not permit access by smaU chUdren. OutfaU pipes above 48 inches in diameter should be fenced. Maintenance Routine maintenance activity is often thought to consist mostiy of sediment and trash and debris removal; however, these activities often constitute only a small fraction ofthe maintenance hours. During a recent study by Caltrans, 72 hours of maintenance was performed annually, but only a Uttie over 7 hours was spent on sediment and trash removal. The largest recurring activity was vegetation management, routine mowing. The largest absolute number of hours was assodated wi& vector control because of mosquito breeding that occurred in the stiUing basins (example of standing water to be avoided) instaUed as energy dissipaters. In most cases, basic housekeeping practices such as removal of debris accumiUations and vegetation 6 of 10 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Extended Detention Basin TC-22 management to ensure thatthe basin dewaters completely in 48-72 hours is suffident to prevent creating mosquito and other vector habitats. Consequentiy, maintenance costs should be estimated based primarUy on the mowing frequency and the time required. Mowing shoiild be done at least annuaUy to avoid estabHshment of woody vegetation, but may need to be perfonned much more frequentiy if aesthetics are an important consideration. Typical activities and frequendes indude: • Schedule semiannual inspection for the beginning and end of the wet season for standing water, slope stabUity, seciment accumulation, trash and debris, and presence of burrows. • Remove accumulated trash and debris in the basin and around the riser pipe during the semiannual hispections. The frequency of this activity may be altered to meet specific site conditions. • Trim vegetation at the beginning and end of the wet season and inspect monthly to prevent estabUshment of woody vegetation and for aesthetic and vector reasons. • Remove accumulated sediment and regrade about every 10 years or when the accumulated sediment volume exceeds 10 percent of the basin volume. Inspect the basin each year for accumulated sediment volume. Cost CoTistTTicti'on Cost The constmction costs assodated with extended detention basins vary considerably. One recent study evaluated the cost of aU pond systems (Brown and Schueler, 1997). Adjusting for inflation, the cost of diy extended detention ponds can be estimated witli the equation: C = i2.4V°'7^° where: C = Constmction, design, and permitting cost, and V = Volume (ft?). Using this equation, typical constmction costs are: $ 41,600 for a 1 acre-foot pond $ 239,000 for a 10 acre-foot pond $ 1,380,000 for a 100 acre-foot pond Interestingly, these costs are generaUy sUghtiy higher than the predicted cost of wet ponds (according to Brown and Schueler, 1997) on a cost per total volume basis, which highUghts fhe difficulty of developing reasonably accurate constmction estimates. In addition, a typical facUity constmcted by Caltrans cost about $160,000 with a capture volume of only 0.3 ac-ft. An economic concem associated with dry ponds is that they might deti-act sUghtiy from the value of adjacent properties. One study foimd that diy ponds can actuaUy detract from the January 2003 California Stormwater BMP Handbook 7 of 10 New Development and Redevelopment www.cabmphandbook, com TC-22 Extended Detention Basin perceived value of homes adj acent to a dry pond by between 3 and 10 percent (Emmerling- Duiovo, 1995). Mamtencmce Cost For ponds, the annual cost of routine maintenance is typicaUy estimated at about 3 to 5 percent of the construction cost (EPA website). Altematively, a community can estimate the cost of fhe maintenance activities outiined in the maintenance section. Table 1 presents the maintenance costs estimated by Caltrans based on thdr experience with five basins located in southem Califomia. Again, it should be emphasized that the vast majority of hours are related to vegetation management (mowing). Table 1 Estimated Average Annual Maintenance Effort Activity Labor Hours Equipment & Material ($) Cost Inspections 4 7 183 Maintenance 49 126 22S2 Vector Control 0 0 0 Administration 3 0 132 Materials -535 535 Total 56 $668 $3,132 References and Sources of Additional Information Brown, W., andT. Schueler. 1997. The Economics of Stormwater BMPs in the Mid-Atlantic Region. Prepared for Chesapeake Research Consortium. Edgewater, MD. Center for Watershed Protection. ElHcott City, MD, Denver Urban Drainage and Flood Control District, 1992. Urban Storm Drainage Criteria Manual—Volume 3: Best Management Practices. Denver, CO. EmmerUng-Dinovo, C. 1995. Stormwater Detention Bashis and Residential Locational Dedsions, Water Resources Bulletin 31(3): 515-521 GaUi, J. 1990. Thermal Impacts Assodated witk Urbanization and Stormwater Management Best Management Practices. MetropoUtan Washington Cbundl of Govemments. Prepared for Maryland Department of the Environment, Baltimore, MD. GKY, 1989, Outlet Hydraulics of Extended Detention Facilities for tlie Northern Virginia Planning District Commission. MacRae, C. 1996, Experience from Morphological Research on Canadian Streams: Is Control of fhe Two-Year Frequency Runoff Event the Best Basis for Stream Channd Protection? In Effects of Watershed Development and Management on Aquatic Ecosystems. American Society of CivU Engineers. Edited by L. Roesner. Snowbird, UT. pp. 144-162. 8 of 10 Califbrnia Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbooks.com January 2003 Extended Detention Basin TC-22 Maryland Dept of the Environment, 2000, Maryland Stormwater Design Manual: Volumes 1 & 2, prepared by MDE and Center for Watershed Protection. http://www.mde.state.md.us/environment/wma/stormwatermanual/index.htinl Metzger, M. E., D. F. Messer, C. L. Bdtia, C. M. Myers, and V, L, Kramer, 2002. The Dark Side Of Stormwater Runoff Management: Disease Vectors Assodated Witii Stmctural BMPs, Stormwater 3(2): 24-39, Santana, F,, J, Wood, R, Parsons, and S. Chamberlain, 1994, Control of Mosquito Breeding in Permitted Stormwater Systems. Prepared for Southwest Florida Water Management District, BrooksvUle, FL. Schueler, T. 1997. Influence of Ground Water on Performance of Stormwater Ponds in Florida, Watershed Protection Techniques 2(4):525-528. Watershed Management Institute (WMI). 1997, Operation, Maintenance, and Management of Stormwater Management Systems. Prepared for U.S. Environmental Protection Agency, Office of Water. Washington, DC. Young, G.K., et al., 1996, Evaluation and Management of Highway Runoff Water Quality, PubUcation No. FHWA-PD-96-032, U.S. Department ofTransportation, Federal Highway Administration, Office of Environment and Planning. Information Resources Center for Watershed Protection (CWP), Environmental QuaUty Resources, and Loiederman Associates, iggy. Maryland Stormwater Design Manual. Draft, Prepared for Maryland Department of the Environment, Baltimore, MD. Center for Watershed Protection (CWP), 1997. Stormwater BMP Design Supplement for Cold Climates. Prepared for U,S, Environmental Protection Agency, Office of Wetiands, Oceans and Watersheds. Washhigton, DC. U.S. Environmental Protection Agency (USEPA). 1993. Guidance Specifying Management Measuresfor Sources of Nonpoint Pollution in Coastal Wafers, EPA-840-B-92-002, U,S, Environmental Protection Agency, Office of Water, Washington, DC. January 2003 California Stormwater BMP Handbook 9 of 10 New Development and Redevelopment www.cabmphandbook.com TC-22 Extended Detention Basin MAXIMUM ELEVATION-^- OF SAFETY STORM \ MAXIMUM ELEVATION ^ . OF ED POOL SPILLWAY PLAN VIEW EUBANKMENT- ANTI-SEEP COLLAK or - FILI tK (JIAHHKAfJM -mi_ir='ii PROFILE Schematic of an Extended Detention Basin (MDE, 2000) 10 of 10 California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbooks.com January 2003 c Vegetated Swale TC-30 Design Considerations • Tnbutary Area • Area Required • Slope • Water Availability c Description Vegetated swales are open, shaUow channds with vegetation covering the side dopes and bottom that coUed: and slowly convey runoff flow to downstream disdiaige points. They are designed to treat runoff through filtering by the vegetation in the channd, filtering through a subsoil matrix, and/or infiltration into the underlyii^ soils. Swales can be natural or manmade. They trap particulate poUutants (suspended scJads and trace metals), promote infiltration, and reduce the flow vdocity of stormwater runoff. V^efcated swales can serve as part of a StormwatEr drainage system and can rejdace curbs, gutters and storm sewer systems. Califomia Experience Caltrans constructed and macdtored six vegetated swales in southem Caiifomia. These swales were generaUy effective m redudng the vciume and mass of pollutants in runoff. Even in the areas where the armual rainfall was only about lo inches/yr, the vegetation did not require additional irrigation. One factor that strongly affected performance was the presence of large numbers of gopters at most of the sites. The gojdiers created earthen mounds, destroyed vegetation, and generaUy reduced the effectiveness of tiK contrds for TSS reduction. Advantages • ff paxipeily designed, vegetated, and operat3ed, swales can serve as an aesthetic, potentially ine}q)ensive urban development or roadway drainage conveyance measure witih significant collata:^ water quaHty baiefits. Targeted Constituents EI Sediment • EI Nutrients . • EI Trash •."'.••• E! Meys „:. A El Bactena • 0 Ql and Grease A El Or^nics A Legend (RBimv^EffKtStmm^ • Low • High • Medium January 2003 California Stormwater BMP Handbook New Development and Redev efcipment www.cabmpihardbooks.com 1 of 13 TC-30 Vegetated Swale • Roadside ditches should be regarded as significant potential swale/buffer strip sites and should be utilized for this purpose whenever possible. Limitations • Can be difficult to avoid channelization. • May not be appropriate for industrial sites or locations where spiUs 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 these practices to function properly. • They are impractical in areas with steep topography. • They are not effective and may even erode when flow vdodties are high, if fhe grass cover is not properly maintained. • In some places, their use is restricted by law: many local munidpaUties require curb and gutter systems in residential areas. • Swales are mores susceptible to faUure if not properly maintained fhan other treatment BMPs. Design and Sizing Guidelines • Flow rate based design determined by local requirements or sized so that 85% of the annual runoff volume is discharged at less than the design rainfaU intensity. • Swale should be designed so that the water levd does not exceed 2/srds the hdght of the grass or 4 inches, which ever is less, at the design treatinent rate. • Longitudinal slopes shouldnot exceed 2.5% • Trapezoidal channels are normaUy recommended but ofher configurations, such as parabohc, can also provide substantial water quaUty improvement and may be easier to mow than designs with sharp breaks in slope. • Swales constmcted in cut are preferred, or in fill areas that are far enough from an adj acent slope to ininimize the potential for gopher damage. Do not use side slopes constmcted of fiU, which are prone to structural damage by gophers and other burrowing animals. • A diverse sdection of low growing, plants that thrive imder the spedfic site, climatic, and watering conditions should be specified. Vegetation whose growing season corresponds to the wet season are preferred. Drought tolerant vegetation should be considered espedaUy for swales that are not part of a regularly inigated landscs^jed 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 Califbrnia Stormwater BMP Handbook January 2003 New Development and Redevelopment www. cabmphandbooks.com Vegetated Swale TC-30 Construction/Inspection Considerations • Include directions in the specifications for use of appropriate fertiUzer and soil amendments based on soil properties determined through testing and compared to the needs of fhe vegetation requirements. • InstaU swales at fhe time of the year when tiiere is a reasonable chance of successful estabUshment without irrigation; however, it is recognized that rainfaU hi a given year may not be sufficient and temporary irrigation may be used. • If sod tiles must be used, they should be placed so that there are no gaps between fhe tiles; stagger the ends of fhe tiles to prevent fhe formation of channds along fhe swale or strip. • Use a roUer on the sod to ensure that no air pockets form between the sod and the soU. • Where seeds are used, erosion controls wUl be necessary to protect seeds for at least 75 days after the first rainfaU of the season. Performance The Uterature suggests that vegetated swales represent a practical and potentially effective technique for controUing urban runoff quaUty. WhUe Umited quantitative performance data exists for vegetated swales, it is known that dieck dams, sUght slopes, permeable soUs, dense grass cover, increased contact time, and smaU storm events aU contribute to successful poUutant removal by the swale system. Factors decreasuig the effectiveness of swales include compacted soils, short runoff contact time, large storm events, frozen ground, short grass heights, steep slopes, and high runoff velocities and discharge rates. Conventional vegetated swale designs have achieved mixed results in removing particulate pollutants, A study performed by the Nationwide Urban Runoff Program (NURP) monitored three grass swales in the Washington, D,C., area and found no significant improvement in urban runoff quaUty for the pollutants analyzed. However, the weak performance of these swales was attributed to the high flow vdodties in the swales, soU compaction, steep slopes, and short grass hdght. Another proj ect in Durham, NC, monitored fhe performance of a carefuUy designed artificial swale that recdved runoff from a commerdal parking lot. The proj ect tracked 11 storms and conduded that particulate concentrations of heavy metals (Cu, Pb, Zn, and Cd) were reduced by approximately 50 percent However, fhe swale proved largdy ineffective for removing soluble nutrients. The effectiveness of vegetated swales can be enhanced by adding check dams at approximately 17 meter (50 foot) increments along thdr length (See Figure 1). These dams maximize the retention time within the swale, decrease flow vdodties, and promote particulate settiing. FinaUy, tiie incorporation of vegetated filter strips paraUd to fhe top of the channel banks can hdp to treat sheet flows entering the swale. Only 9 studies have been conducted on all grassed channels designed for water quaUty (Table 1). The data suggest relatively high removal rates for some pollutants, but negative removals for some bacteria, and fair performance for phosphorus. January 2003 California Stormwater BMP Handbook 3 of 13 New Development and Redevelopment www.cabmphandbooks.com Vegetated Swale TC-30 The topography of the site should perinit the design of a channel with appropriate slope and cross-sectional area. Site topography may also dictate a need for additional stmctural controls. Recommendations for longitudinal slopes range between 2 and 6 percent. Flatter slopes can be used, if suffident to provide adequate conveyance. Steep slopes increase flow velodty, decrease detention time, and may require energy dissipating and grade check. Steep slopes also can be managed using a series of check dams to terrace the swale and reduce the slope to within acceptable Umits. The use of check dams with swales also promotes infUtration. Additional Design Guideiines Most ofthe design guideUnes adopted for swale design spedfy a minimum hydrauUc residence time of 9 minutes. This criterion is based on lhe results of a single study conducted in Seattie, Washington (Seattle Metro and Washington Depaitment of Ecology, 1992), .andjs jiQtw;elL. supp.Qrted Analysis of the data coUected in that study indicates that poUutant removal at a residence time of 5 minutes was not significantiy different, although there is more variabUity in that data. Therefore, additional research in fhe design criteria for swales is needed. Substantial pollutant removal has also been observed for vegetated controls designed solely for conveyance (Barrett et al, 1998); consequentiy, some flexibiUty in the design is warranted. Many design guideUnes recommend that grass be frequentiy mowed to maintain dense coverage near the ground surface. Recent research (ColweU et al., 2000) has shown mowing frequency or grass hdght has little or no effect on poUutant removal. Summary of Design Recommendations 1) The swale should have a length that provides a ininimum hydrauUc residence time of ^t least 10 minutes. The maximum bottom width should not exceed 10 feet unless a dividing berm is provided. The deptii of flow should not exceed 2/3rds the hdght of tiie grass at fhe peak of fhe water quaUty desigi storm intensity. The channel slope should not 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 than 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 ofp^s^ , — -7^^ s ^ / z. 5) The swale can be sized as both a treatment faciUty for fhe design storm and as a conveyance system to pass the peak hydrauUc flows of fhe 100-year storm if it is located "on-line." 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 this purpose whenever possible. If flow is to be introduced through curb cuts, place pavement slightiy above the elevation of the vegetated areas. Curb cuts should be at least 12 inches wide to prevent dogging. 7) Swales must b e 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, select fine, dose-growing, water-resistant grasses. If possible, divert runoff (other fhan necessary irrigation) during the period of vegetation January 2003 California Stormwater BMP Handbook 5 of 13 New Development and Redevelopment www.cabmphandbooks.com TC-30 Vegetated Swraie Table 1 Grassed swale pollutant removal efficiency data Removal Efficiencies (% 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 -314 42-62 -100 grassed channel Seattle Metro and Washington Department of Ecology 1992 60 45 --25 2-16 -25 grassed channel Seattle Metro and W^ashington Department of Ecology, 1992 83 29 --25 46-73 -25 grassed channel Wang et al, 1981 80 ---70-80 -dry swale Dorman etal., 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 While it is difficult to distinguish between different designs based on the smaU amount of available data, grassed channels generally have poorer removal rates than wet and dry swales, although some swales appear to export soluble phosphorus (Harper, 1988; Koon, 1995). It is not dear why swales export bacteria. One explanation is that bacteria thrive in fhe warm swale soUs. Siting Criteria The suitabiUty of a swale at a site wUl depend on land use, size of the area serviced, soil type, slope, imperviousness of fhe contributing v/atershed, 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 fhan 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) m Comparable performance to wet basins • Liinited to treating a few acres • AvaUabUity of water durtng dry periods to maintain vegetation • Sufficient avaUable land area Research in tiie Austin area indicates that vegetated controls are effective at removing poUutants even when dormant. Therefore, irrigation is not required to maintain growth during dry periods, but may be necessary only to prevent the vegetation from dying. 4 of 13 California Stormwater BMP Handbook New Development and Redeveiopment www.cabmphandbooks.com January 2003 vegetated Swale TC:30_ The topography of the site should permit the design of a channel with appropriate slope and cross-sectional area. Site topography may also dictate a need for additional stmctural controls. Recommendations for longitudinal slopes range between 2 and 6 percent. Flatter slopes can be used, if suffident to provide adequate conveyance. Steep slopes increase flow velodty, decrease detention time, and may reqmre energy dissipating and grade check. Steep slopes also can be managed using a series of check dams to terrace the swale and reduce the slope to within acceptable Hmits. The use of check dams with swales also promotes infiltration. Additional Design Guidelines Most of fhe design guideUnes adopted for swale design spedfy a minimum hydrauUc.residence ti.me_of g minute^^ criterion is based on the results of a single study conducted in Seattie, Washington (Seattle Metro and Washington Department of Ecology, 1992), and isuQti^eU- suppprted, Analysis of the data coUected in that study indicates that poUutant removal at a residence time of 5 minutes was not significantiy different, although there is more variabUity in that data. Therefore, additional research in the design criteria for swales is needed. Substantial pollutant removal has also been observed for vegetated controls designed solely for conveyance (Barrett et al, 1998); consequentiy, some flexibiUty in the design is warranted. Many desi^ guideUnes reco i^ near the ground surface. Recent research (ColweU et al., 2000) has shown mowing frequency or grass hdght has little or no effect on poUutant removal. Snmmctry of Design Recommendations 1) The swale should have a length that provides a minimum hydrauUc residence time of ^ ^t least IQ minutes. The maximum bottom width should not exceed 10 feet unless a dividing berm is provided. The depth of flow shpiUd not esce^^^^ the grass at fhe peak of the water quaUty design, storm intensity, jftie^d^^ should not exceed 2.5%. 2) A design grass height of 6 inches is recommended. 3) Regardless of fhe recommended detention time, tiie swale shpiUd_be^ not less ti ipo feet in laigtii, 4) The width of the swale should be determmed using Manning's Equation, at the peak of the design storm, using a Manning's n of_p;2^ ^r? c--z.£ —- 1^^^ ^ /T^J-L/O^ 5) The swale can be sized as both a treatment facUity for fhe design storm and as a conveyance system to pass the peak hydrauUc flows of fhe 100-year storm if itis located "on-line." The side slopes shq^^ 6) Roadside ditches should be regarded as significant potential swale /buffer strip sites and should be utiUzed for this purpose whenever possible. If flow is to be introduced through curb cuts, place pavement slightiy above fhe elevation ofthe vegetated areas. Curb cuts should be at least 12 inches wide to prevent dogging. 7) Swales must b e vegetated in order to provide adequate treatment of runoff. It is important to maximize water contact with vegetation andthe goU surface. For general purposes, select fine, dose-growing, water-resistant grasses. If possible, divert runoff (other fhan necessary irrigation) during the period of vegetation January 2003 California Stormwater BMP Handbook 5 of 13 New Development and Redevelopment www.cabmphandbooks.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 Ufe of a vegetated swale system is directiy proportional to its maintenance frequency. If properly designed and regularly maintained, vegetated swales can last indefinitely. The maintenance objectives for vegetated swale systems indude keeping up the hydrauUc and removal effidency of the channel and maintaining a dense, healthy grass cover. Maintenance activities should indude periodic mowing (with grass never cut shorter than fhe design flow depth), weed control, watering during drougjit conditions, reseeding of bare areas, and dearing of debris and blockages. Cuttings shouldbe removed from the channd and disposed in a local composting facUity. Accumulated sediment should also be removed manuaUy to avoid concentrated flows in the swale. The appUcation of fertiUzers and pesticides shouldbe minimal. Another aspect of a good maintenance plan is repairing damaged areas wilhin a channel. For example, if the channd develops mts or holes, it should be repaired utihzing a suitable soU that is properly tamped and seeded. The grass cover should be thick; if it is 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 annually for erosion, damage to vegetation, and sediment and debris accumulation preferably atthe end of the wet season to schedule summer maintenance and before major faU runoff to be sure fhe swale is ready for winter. However, additional inspection after periods of heavy runoff is desirable. The swale should be checked for debris and litter, and areas of sediment accumulation. • Grass hdght and mowing frequency may not have a large impact on poUutant removal. Consequentiy, mowing may only be necessary 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 Utter removal is determined through periodic inspection, but litter should always be removed prior to mowing. • Sediment accumulating near culverts and in channels should be removed when it buUds up to 75 mm (3 in.) at any spot, or covers vegetation. • Regularly inspect swales for pools of standing water. Swales can become a nuisance due to mosquito breeding in standing water if obstmctions devdop (e.g. debris accumulation, hivasive 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.cabmphandbooks.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 constmction cost of grassed channels at approximately $ 0,25 per ft?. This price does not indude design costs or contingendes. Brown and Schueler (1997) estimate these costs at approximatdy 32 percent of constmction costs for most stormwater management practices. For swales, however, these costs would probably be significantiy higher since the constmction costs are so low compared with other practices. A more reaUstic estimate would be a total cost of approximately $0.50 per ft?, whidi compares favorably with other stormwater management practices. January 2003 California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbooks.com 7 of 13 o TC-30 ( Vegetated Swale Table 2 Swale Cost Estimate (SEWRPC, 1991) UnitCost Total Cost CompOTient Unit Extent Low Moderate High Low Moderate High Uobiliration / Demobilization-Light Swals 1 $107 $274 $441 $107 $274 $441 Site Preparatlcn Clearing'* Grubbingf. Genenal Escavatiorf LSVBI and Till" Acre Acre Yd' Yd^ 0.5 0.25 372 1,210 $2,200 $3.aMI $2.10 $0.20 $3,800 $5,200 $3.70 $0.35 $S.400 $6,600 $S.30 $0.50 M - O g $1,900 $1,300 $1,376 $424 $2,700 $1,BS0 $1,972 $G05 Siiss Davsloprnent Sal vagoid Topsoil Seed, and Mulch'.. SotP Vd= Yd= 1,210 1,210 $0.40 $1.20 $1.00 $2.40 $1.60 $3.60 $4B4 11,452 $1,210 £2,904 $1,936 $4,356 Subtotal -----$5,116 $i9.3BiB $13,EG0 Contingencies Swale 1 25% 25"/. 25% * 1,279 $2,347 $3,415 ------$6.3S5 $11,735 $17,075 Source: (SEWRPC, 1891) Note: MabilizafiorMsmabilizatian rsfersto thearganizstlcn and pianning involved In estaUistilng a vegsiafvasmto. • Swale hi3s a bottom width of 1.0 foot, a top ftldth of 10 feet with 1:3 side slopes, and a 1,000-fool lengtti. "Area cieared = (topwidth + 1Q feet] x swale length. 'fvis grubbed =; (lopwidth x swale length). 'Volume excavaied - (0.67 x top ividthx swale depth) x swale length (parabolic cross-section). "Area tilled = (topwidth + 8fswale deplh^ x swale length fparabolc cross-section). 3(tDp width) ' Area seeded - area cleared x 0.5. ' Arei3 sodded - area cleared x 0.5. 8 of 13 California Stormwater BMP Handbook New Development and Redevelopment www.cijmphandbooks. com January 2003 Vegetated Swale TC-30 Table 3 Estimated Maintenance Costs fSEWRPC 1991) Swale Size (Deptti and Top vwdtnj Component Unit Cost 1.5 Foot Depth, One- Foot Bottom Width. 10-Foot Top Widtti 3-FoDtD^th. 3-FoDt Bottom Width. 21-Foot Top Width CoiTsment Lawn Mowing $0.85/1,000 ft*/mowing SO.14/llnearfoot K).21 /SnearfEJOl Lawn maintenaios aree=[1sp widlh 4-lOfes'Qx Isr^h. Mow eight tvnes peryear General Lawn Care $9.00/1,000 fl'/ year $0.1S / llnearfoot SO.28 linear foot Lawn mairrtenancs area = (top widlfi + lOfast) X length Swals Debris and Utter Removal $0.10/linear foot/year $0.10/lin earfoot $0.10/linear fool - Grass Fissseding witli Mulch and Fertilizer $0.30/yd' $0.01 / llnearfoot $0.01 /inear fool Araa roMsgetated equate 1% of lawn milntenancsarea per year Program AdministratiQn and Swale Inspedion $0.15/ linear foot/year, plus $25 / inspect'on $0.15 /linearfoat $0.15/Bnear foot Insped tour times per yesr Total $0.58 / llRiiar foot $0.75/HneM' foof January 2003 Califomia Stormwater BMP Handtxjok New Development and Redevelopment www.cabmphandbooks. com 9 of 13 TC-30 Vegetated Swale Maintenance Cost Caltrans (2002) estimated the expected annual maintenance cost for a swale with a tributary area of approximately 2 ha at approximately $2,700. Since almost all maintenance consists of mowing, tiie cost is fundamentally a function of the mowing frequency. Unit costs developed by SEWRPC are shown in Table 3. In many cases vegetated channels would be used to convey runoff and would require periodic mowing as well, so tiiere may be littie additional cost for the water quality component. Since essentially aU the activities are related to vegetation management, no special training is required for maintenance personnel. References and Sources of Additional Information Barrett, Michael E., Walsh, Patrick M., Malina, Joseph P., Jr., Charbeneau, Randall J, 1998, "Performance of vegetative controls for treating highway runoff," ASCE Journal of Environmental Engineering, Vol. 124, No. 11, pp. 1121-1128. Brown, W., andT, Schueler. 1997. The Economics of Stormwater BMPs in the Mid-Atlantic Region. Prepared for the Chesapeake Research Consortium, Edgewater, MD, by the Center for Watershed Protection, Ellicott City, MD. Center for Watershed Protection (CWP). 1996, Design of Stormwater Fitering Systems. Prepared for the Chesapeake Research Consortium, Solomons, MD, and USEPA Region V, Chicago, IL, by the Center for Watershed Protection, EUicott City, MD. ColweU, Shanti R., Homer, Richard R., and Booth, Derek B., 2000. Characterization of Performance Predictors and Evaluation of Mowing Practices in Biofiltration Swales. Report to King County Land And Water Resources Division and others by Center for Urban Water Resources Management, Department of Civil and Environmental Engineering, University of Washington, Seattie, WA Dorman, M.E., J. Hartigan, R.F. Steg, andT. Quasebarth. 1989, Retention, Detention and Overland Flow for Pollutant Removal From Highway Stormwater Runoff. Vol. 1. FHWA/RD 89/202. Federal Highway Administration, Washington, DC. Goldberg. 1993. Dayton Avenue Swale Biofiltration Study. Seattie Engineering Department, Seattie, WA Harper, H. 1988. Effects of Stormwater Management Systems on Groundwater Quality. Prepared for Florida Department of Environmental Regulation, Tallahassee, FL, by Environmental Research and Design, Inc., Orlando, FL. Kercher, W.C, J,C. Landon, and R, MassardH, 1983, Grassy swales prove cost-effective for water pollution control. Public Works, 16: 53-55. Koon, J. 1995. Evaluation of Water Quality Ponds and Swales in the Issaquah/East LaJce Sammamish Basins. King County Surface Water Management, Seattie, WA, and Washington Department of Ecology, Olympia, WA Metzger, M. E., D. F. Messer, C. L. Beitia, C. M. Myers, and V. L. Kramer. 2002. The Dark Side Of Stormwater Runoff Management: Disease Vectors Associated With Structural BMPs. Stormwater 3(2): 24-39.Oakland, P-H. 1983. An evaluation of stormwater pollutant removal 10 of 13 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Vegetated Swale TC-30 through grassed swale treatment. In Proceedings ofthe International Symposium of Urban Hydrology, Hydraulics andSediment Control, Lexington, KY. pp. 173-182. Occoquan Watershed Monitoring Laboratory. 1983. Final Report: Metropolitan Washington Urban Runoff Project. Prepared for the Metropolitan Washington Coundl of Govemments, Washington, DC, by the Occoquan Watershed Monitoring Laboratory, Manassas, VA. Pitt, R., and J, McLean, 1986, Toronto Area Watershed Management Strategy Study: Humber River Pilot Watershed Project. Ontario Ministry of Environment; Toronto, ON. Schuelei", T, 1997. Comparative Pollutant Removal Capability of Urban BMPs: A reanalysis. Watershed Protection Techniques 2(23:379-383, Seattie Metro and Washington Department of Ecology. 1992, Biofiltration Swale Performance: Recommendations and Design Considerations. Publication No, 657. Water Pollution Control Department, Seattie, WA Southeastern Wisconsin Regional Planning Commission (SWRPC). 1991. Costs of Urban Nonpoint Source Water Pollution Control Measures. Technical report no. 31. Southeastem Wisconsin Regional Planning Commission, Waukesha, WI. U.S. EPA, 1999, Stormwater Fact Sheet Vegetated Swales, Report # 832-F-99-006 http: //www.epa.gov/owm/mtb/vegswale.pdf, Office of Water, Washington DC. Wang, T, D. SpyridaMs, B. Mar, and R, Homer, 1981, Transport, Deposition and Control of Stm^ Heavy Metals in Highway Runoff. FHWA-WA-RD-39-10. University of Washington, Department of Civil Engineering, Seattie, WA. Washington State Department ofTransportation, 1995, Highway Runoff Manual, Washington State Department of Transportation, Olympia, Washington. Welbora, C, and J. Veenhuis. 1987, Effects of Runoff Controb on the Quantity and Quality of Urban Runoff in Two Locations in Austin, JX. USGS Water Resources Investigations Report No. 87-4004. U.S, Geological Survey, Reston, VA, Yousef, Y,, M. Wanielista, H. Harper, D, Pearce, andR. Tolbert. 1985, Best Management Practices: Removal of Highway Contaminants By Roadside Swales. University of Central Florida and Florida Department ofTransportation, Orlando, FL. Yu, S., S, Bames, and V. Gerde, 1993. Testing of Best Management Practices for Controlling Highway Runoff. FHWA/VA-93-R16. Virginia Transportation Research Coundl, CharlottesvUle, VA Infoimation Resources Maryland Department of the Environment (MDE). 2000. Maryland Stormwater Design Manual, www, mde. state, md.us /environment/wma/stormwatermanual. Accessed May 22, 2001. Reeves, E. 1994. Performance and Condition of Biofiiters in the Pacific Northwest. Watershed Protection Techniques 1(3): 117-119. January 2003 California Stormwater BMP Handbook 11 of 13 New Development and Redevelopment www .cabmphandbooks. com TC-30 Vegetated Swale Seattie Metro and Washington Department of Ecology. 1992. Biofiltration Swale Performance. Recommendations and Design Considerations. Publication No. 657. Seattie Metro and Washington Department of Ecology, Olympia, WA USEPA 1993. Guidance Specifying Management Measures for Sources of Nonpoint Pollution in Coastal Waters. EPA-840-B-92-002. U.S. Environmental Protection Agency, Office of Water. Washington, DC. Watershed Management Institute (WMI). 1997, Operation, Maintenance, and Management of Stormwater Management Systems. Prepared for U,S. Environmental Protection Agency, Office of Water. Washington, DC, by the Watershed Management Institute, Ingleside, MD. ^^^^ 12 of 13 California Stormwater BMP Handbook January 2003 New Development and Redevelopment www.cabmphandbooks.com Vegetated Swale jmufcfioii. (u) Crew a'ttiim urswalt »tth direk itm. No-tntlon: L = L»nolh o( swnle impoi«ilm«fit sro.! (w*" ehoek 4.vt> {fV; ^t,) tVimcmioniil visw nf s»«l<; iniiMumlnit'iil ana.. OJ = D»ptl\ ol chock <lt<m (fl) Ss = StJtMni !Hp« o( »mi» (ft/tt) W = Tao wktth oteMeKdOMW Wp = B»tiom wWih «/ ctwck cl»ni jft) = Ratto o( hOfliomaHo ycrUwil chiitiue In swi\l*slilo slji* ((vfi) TC-30 January 2003 California Stormwater BMP Handbook New Development and Redevelopment www.cabmphandbooks.com 13 of 13 The primary purpose of storm drains is to carry rain water away from developed areas to prevent flooding. Storm drains are r>r>t connected to sanitary sewer systems and treatment plants. Untreated storm water and the pollutants it carries flow directiy to creeks, lagoons and the ocean. EVERYONE is responsible for protecting storm water! Storm Water pollution prevention is a shared duty between the City of Carlsbad and the Community. Storm drains on public property are monitored and cleaned by the City. Everyone has a part to play in keeping our storm drains free of poilutants. Methods used to prevent storm water pollution are called Best Management Practices (BMPs). Storm water pollution comes from a variety of sources including: • Oil, fuel and fluids from vehicles and heavy equipment • Lawn clippings, pesticide and fertilizer runoff from landscaping • Sediment and concrete from construction and landscaping activities • Bacteria from human and animal waste • Litter The City ofCarlsbad is committed to improving water quality and reducing the amount of pollutants that enter our precious waterways. Having a clean environment is of primary importance for our health and economy. Clean waterways provide commercial opportunities, recreation, fish habitat and " ' " ' " . add beauty to our ' landscape. All of us benefit from clean water - and all of us have a role in making and keeping our creeks, lagoons and ocean clean. Sweep or Rake • Sweep up debris and put it in a trash can. Do not use a hose to wash off sidewalks, parking areas and garages. Rake up yard waste and start a compost pile. Reduce Use of Landscape Chemicals • Minimize the use of lawn and garden care products such as pesticides, insecticides, weed killers, fertilizers, herbicides and other chemicals. Avoid over-irrigation which washes chemicals into the gutter and storm drains. Use Soap Sparingly • When washing your car at home, use soap sparingly, divert washwater to landscaped areas and pour your bucket of soapy water down the sink. Never wash your car in the street Clean up After Your Pets • Take a bag when you walk your pets and be sure to always clean up after them. Flush pet waste down the toilet or dispose of it in a sealed plastic bag and throw it in the trash. ; Buy Non-Toxic Products • When possible, use non-toxic products for household cleaning. If you must use a toxic cleaning product, buy small quantities, use it sparingly and properly dispose of unused portions. For the Household Hazardous Waste coilection facility nearest you, call 1 -800-CLEANUP. ^ e City is regulated by a municipal storm water permit lhat was issued by the State Water Resources Control Board. The City's Storm Water Program helps to ensure compliance with the permit by: • Inspecting Carlsbad businesses and requiring BMPs to prevent pollution • Investigating and eliminating illegal discharges to the storm water system ' Overseeing and conducting water quaiity monitoring programs • Educating the public about ways to prevent storm water pollution In the strictest definition, only rain water can legally enter the storm drain. However, the permit currently allows some types of discharges into storm drains when BMPs are used to reduce pollutants. Some examples include: • Landscape irrigation and lawn watering runoff • Dechlorinated pool water I Ki^te,^ • Residential car washing < y/_ \ r**^; • Potable water sources ^ • Foundation drains • Water line flushing '^'"—(t The Storm Water Program operates a hotline and an e-mail address to receive referrals about storm water poiiution and illegal discharges and to answer questions about storm water pollution prevention. if you see someone dumping or washing waste or pollutants to the street or storm drain, please cail the hotline at ; : or send an email to ^;.zorYv .-^-•s.-r, <• ;; .{;.•:•'•.•..•.:)•:'. This information is entered into the City's Request for Action system and is routed to the appropriate person for response. ]yfy':r : 'Vii \ • stmor :' sf -rr'- V M"^? • • • • ' • Visit the Cit/s website at 5, >i;:i > : i c-' i v • : to view brochures, documents or link to other water quality websites. • Call the hotline at • i i-i to you. '»'- to have information sent To view a copy ofthe Permit, please go to 5S IsiiJ '-..H Significant efforts are being made by City departments to help keep our waterways clean. A few program activities are listed below: • Educating the public and City employees about storm water poiiution prevention through our website, brochures, publications, workshops and public events • Inspecting construction sites to ensure that developers are implementing Best Management Practices • Implementing Best Management Practices at City facilities • Conducting industrial and commerdal inspections to ensure businesses are aware of and complying with the storm water program requirements • Addressing storm water requirements for new deveiopment and significant redevelopment • Conducting water quality monitoring in the storm drain system and in our creeks, lagoons and ocean • Investigating reports of illegal discharges • Implementing a Watershed Urban Runoff Management Plan (WURMP) with the County and other North County cities to protect all of our waterways Preservation Of Existing Vegetation EC-2 Description and Purpose Carefully planned pa-eservatioa of existing vegetation minimizes the potsential of removing or injuxiiig existing trees, vines, shmbs, andgrass^ that protect soil fiximerosioii. Suitable Applications Preservation of existing vegetation is suitable for use on most projects. Large project sites often pt)vide the greatest opportunity for use of this BMP. Suitable appiications indude the following: • Areas witiiin the aitewhei^ no constrnctionaxlivity occurs, or occurs at alater date. Uiis BMP is espedalily suitable to multi year projects where jading can be phased • i^j-eas where natural vegetation exists and is desigoated for preservation. Such areas cftm mclude steep slopes, watercourse, and building sites in wooded areas. • Areas whare local, state, and federal government require preservation, such as vernal pools, wetlands, marshes, certain oak trees, etc These areas are usually desigoated on the plans, or in the spedfications, permits, or environmental documents. • Where vegetation designated for ultimate removal can be temporarily pareserved and be utiUzed for erosion conti"ol and sediment contrd. Objectives EC SE TR WE NS WM Bosion Control Sediment Control Tracking Control Wind Erosion Control Non-Stormwater l^nagement Control Waste IVIanagement and IVlaferials Pollution Control Legend: EZI Primarv Objective (3 Secondary Objective Targeted Constituents Sediment El Nutrients Trasti Meys Bacteria Qi and Grease : Organics Potential Alternatives None January 2003 Califomia Stormwater BMP Handbook Construction www.cabmphandbooks.com 1 of 4 w EC-2 Preservation Of Existing Vegetation Limitations • Requires forward planning by the owner/developer, contractor, and design staff. • Limited opportunities for use when project plans do not incorporate existing vegetation into the site desiga • For sites with diverse topography, it is often difficult and expensive to save existing trees while grading the site satisfactory for the planned development. Implementation The best way to prevent erosion is to not disturb the land, hi order to reduce the impacts of new development and redevelopment, projects may be designed to avoid distuihing land in sensitive areas of the site (e.g., natural watercotirses, steep slopes), and to incorporate unique or desirable existing vegetation into the site's landscfqping plan. Clearly marking and leaving a buffer area around these unique areas during construction wiU help to preserve these areas as well as take advantage of natural erosion prevention and sediment trapping. Existing vegetation to be preserved on the site must be protected from mechanical and other injuiy while the land is being developed. The purpose of protecting existirig vegetation is to ensure the survival of desirable vegetation for shade, beautification, and erosion control. Mature vegetation has extensive root systems that help to hold soil in place, thus reducing erosion. In addition, vegetation helps keep scdl from drying rapidly and becoming susceptible to erosion. To effectively save existing vegetation, no disturbances of any kind should be allowed "Sm" witim a defined area aroimd tiie vegetation. For trees, no construction activity should occur within the drip line ofthe tree. Timing • Provide for preservation of existing vegetation prior to the commencement of dearing and grubbing operations or other soil disturbing activities in areas where no construction activity is planned or wiU occur at a later date. Design and Layout • Mark areas to be preserved with temporary fencing. Indude suffident setback to protect roots. - Orange colored plastic mesh fendng works well. - Use appropriate fence posts and adequate post spadng and depth to completdy support the fence in an upright position. • Locate temporary roadways, stockpiles, and layout areas to avoid stands of trees, shrubs, and grass. • Consider tiie impact of grade changes to existing vegetation and the root zone. • Maintain existing imgation systems where feasible. Temporary irrigation may be required. • Instruct employees and subcontractors to honor protective devices. Prohibit heavy eqxripment, vehicular traffic, or storage of construction materials within the protected area. 2 of 4 Califbrnla Stormwater BMP Handbook January 2003 Construction www, cabmphandbooks,com Preservation Of Existing Vegetation EC-2 Costs There is Uttie cost assodatsd witii preserving existing v^etation if properiy planned during the project design, and these costs may be offset by aesthetic benefits that enhance property values. During construction, the costfor preserving existing vegetation will likdy be less than the cost of applying erosion and sediment controls to tiie disturbed area. Replacing v^etation inadvertentiy destroyed during construction can be extremdy e:^ensive, sometimes in excess of $10,000 per tree. Inspection and Maintenance During construction, the limits of disturbance should remain dearly marked at aU times. Iirigation or maintenance of existing vegetation should be described in the landscaping plan. If damage to protected trees stiU occurs, maintenance guideUnes described bdow should be foUowed: • Verify that protective measures remain in place. Restore damaged protection measxares immediately. • Serious tree irg uries shaU b e attended to by an arborist. • Damage to the crown, trunk, or root system of a retained tree shall be repaired immediatdy. • Trench as far fi'om tree trunks as possible, usually outside of the tree diip Une or canopy. Curve trenches aromid trees to avoid large roots or root concentrations. If roots are encountered, consider tunneUng imder Ihem. When trenching or tunneling near or under trees to be retained, place timnds at least 18 in. below the ground surface, and not below the tree center to minimize impact on the roots. • Do not leave tree roots exposed to air. Cover exposedroots with soU as soon as possible. If soil coveiing is not practical, protect ejqjosed roots with wet burlap or peat moss until the tunnel or trench is ready for backfiU. • Qeanly remove lie ends of damaged roots vrith a smooth cut. • FiU trenches and tunnels as soon as possible. Careful filUng and tamping wiU eUminate air spaces in the soU, which can damage roots. • If bark damage occurs, cut back aU loosened bark into the undamaged area, with the cut tapered at the top and bottom and drainage provided at the base of the wood. Limit cutting the undamaged area as much as possible. • Aerate soil that has been compacted over a trees root zone by punching holes 12 in. deep with an iron bar, and moving the bar back and forth until the soU is loosened. Place holes 18 in. apart throughout the area of compacted soil under the tree crown. • FertiUzation - Fertilize stressed or damaged broadleaf trees to aid recovery. - Fertilize trees in the late faU or eariy spiing. Janua-y 2003 California Stomnwater BMP Handbook 3 of 4 Construction www.cabmphandbooks. com EC-2 Preservation Of Existing Vegetation - Apply fertUizer to the soU over the feeder roots and in accordance with labd instructions, but never doser than 3 ft to the trunk. Increase the fertiUzed area by one-fourth of the crown area for conifers that have extended root systems. • Retain protective measures until aU other construction activity is complete to avoid damage during site deanup and stabUization. References County of Sacramento Tree Preservation Ordinance, September 1981. Stormwater QuaUty Handbooks Construction Site Best Management Practices (BMPs) Manual, State of CaUfomia Department ofTransportation (Caltrans), November 2000. Stormwater Management of the Puget Sound Basin, Technical Manual, PubUcation #91-75, Washington State Department of Ecdogy, Februaiy 1992. Water QuaUty Management Plan for The Lake Tahoe Region, Volume II, Handbook of Management Practices, Tahoe Regional Planning Agency, November 1988. 4 of 4 California Stormwater BMP Handbook January 2003 Construction www. cabmptTandbooks,com JUST ONE OF MANY DESIGN FEATURES THAT SEPARATES US FROM THE PACK... It's called an intemal bypass system. The objective of stormwater treatment is to remove pollutants. That's the easy part. The trick is to prevent previously captured pollutants from scouring during peak, infrequent high flows. Many systems claim they can. However, most can't. Stormceptor's patented "internal" bypass system eliminates this concern. Stormceptor's extensive lab testing, field evaluations and testimonials prove it. During normal rainfall Stormceptor removes and retains up to 80% of Total Suspended Sohds and 98% of Free Oils and Hydrocarbons. 1^ Stormceptor ® Higli jiow bijpnss prevents scouring Represents normal flow Hydro Conduit Dj\'i.sioii 800-909-7763 • www.rinkerstGnnceptor.com That's an impressive statistic. Maybe that's why there are more than 11,500 Stormceptors currently in service. No other quaUty treatment device has been challenged more than Stormceptor. Nor has any otiier system been tested more. Time and again, the results have proven that Stormceptor simply works. To learn more about the Stormceptor System and its many superior design features, simply give us a caU or visit our website. Circle #66 on Reader Service Card CHANNEL INSTALLATION (5cm-12.5cm) 1. PREPARE SOIL BEFORE INSTALUNG BU^NKETS. INCLUDING ANY NECESSARY APPUCATION OF UME. FERTIUZER. AND SEED. NOTE: WHEN USING CELL-O-SEED DO NOT SEED PREPARED AREA. CELL-O-SEED MUST BE INSTALLED WITH PAPER SIDE DOWN. 2. BEGIN AT THE TOP OF THE CHANNEL BY ANCHORING THE BLANKET IN A 6" (15cm) DEEP X 6" (15cm) WIDE TRENCH WITH APPROXIMATELY 12" (30cm) OF BL^NKET EXTENDED BEYOND THE UP-SLOPE PORTION OF THE TRENCH. ANCHOR THE BLANKET WITH A ROW OF STAPLES/STAKES APPROXIMATELY 12" (30cm) AP/VRT IN THE BOTTOM OF THE TRENCH. BACKFILL AND COMPACT THE TRENCH AFTER STAPUNG. APPLY SEED TO COMPACTED SOIL AND FOLD REMAINING 12" (30cm) PORTION OF BLANKET BACK OVER SEED AND COMPACTED SOIL SECURE BLANKET OVER COMPACTED SOIL WITH A ROW OF STAPLES/STAKES SPACED APPROXIMATELY 12" (30cm) APART ACROSS THE WIDTH OF THE BLANKET. 3. ROLL CENTER BUNKET IN DIRECTION OF WATER FLOW IN BOTTOM OF CHANNEL. BLANKETS WILL UNROLL WITH APPROPRIATE SIDE AGAINST THE SOIL SURFACE. AOJ. BLANKETS MUST BE SECURELY F/SSTENED TO SOIL SURFACE BY PLACING STAPLES/STAKES IN APPROPRIATE LOCATIONS AS SHOWN IN THE STAPLE PATTERN GUIDE. WHEN USING OPTIONAL DOT SYSTEM™, STAPLES/STAKES SHOULD BE PLACED THROUGH EACH OF THE COLORED DOTS CORRESPONDING TO THE APPROPRIATE STAPLE PATTERN. 4. PLACE CONSECUTIVE BLANKETS END OVER END (SHINGLE STYLE) WITH A 4"-6" (10cm-15cm) OVERLAP. USE A DOUBLE ROW OF STAPLES STAGGERED 4" (10cm) APART AND 4" (10cm) ON CENTER TO SECURE BLANKETS. 5. FULL LENGTH EDGE OF BL.ANKETS AT TOP OF SIDE SLOPES MUST BE ANCHORED WfTH A ROW OF STAPLES/STAKES APPROXIMATELY 12" (30cm) APART IN A 6" (15cm) DEEP X 6" (15cm) WIDE TRENCH. BACKRU AND COMPACT THE TRENCH AFTER STAPUNG. 6. ADJACENT BLANKETS MUST BE OVERLAPPED APPROXIMATELY 2"-5" (5cm-12.5cm) (DEPENDING ON BLANKCT TYPE) AND STAPLED. TO ENSURE PROPER SEAM AUGNMENT. PLACE THE EDGE OF THE OVERLAPPING BLANKET (BLANKET BEING INSTALLED ON TOP) EVEN WITH THE COLORED SEAM STrTCH™ON THE BLANKET BEING OVERLAPPED. 7. IN HIGH FLOW CHANNEL APPUCATIONS, A STAPLE CHECK SLOT IS RECOMMENDED AT 30 TO 40 FOOT (9m-12m) INTERVALS. USE A DOUBLE ROW OF STAPLES STAGGERED 4" (10cm) APART AND 4" (10cm) ON CENTER OVER ENTIRE WIDTH OF THE CHANNEL 8. THE TERMINAL END OF THE BUNKETS MUST BE ANCHORED WfTH A ROW OF STAPLES/STAKES APPROXIMATELY 12" (30cm) APART IN A 6" (15cm) DEEP X 6" (15cm) WIDE TRENCH. BACKFILL AND COMPACT THE TRENCH AFTER STAPUNG. A- CRITICAL POINTS A. OVERLAPS ANO SEAMS B. PROJECTED WATER UNE C. CHANNEL BOTTOM/SIDE SLOPE VERTICES NOTE: * HORIZONTAL STAPLE SPACING SHOULD BE ALTERED IF NECESSARY TO ALLOW STAPLES TO SECURE THE CRITICAL POINTS ALONG THE CHANNEL SURFACE. »* IN LOOSE SOIL CONDITIONS, THE USE OF STAPLE OR STAKE LENGTHS GREATER THAN 6" (15 cm) MAY BE NECESSARY TO PROPERLY /ANCHOR THE BLANKETS. 14649 HIGHWAY 41 NORTH. EVANSVILLE. INDIANA 47725 USA 1-800-772-2040 CANADA 1-800-448-2040 www.nagreen.com SC250 Page 1 of 1 North American Green's SC250 is comprised of a pennanent, high strength three-dimensional nnatting structure incorporated with a straw/coconut fiber matrix. It is designed to provide both extended term, pre-vegetated erosion protection and permanent turf reinforcement in a wide variety of applications, including severe slopes, fiigh flow channels and Stream banks. The straw/coconut fiber matrix enhances the permanent matting's initial mulching and erosion control performance for up to 24 months. Proven in laboratory and field research, the permanent matting's high strength 3-D structure increases the shear resistance of vegetation up to 8 Ibs. per sq. ft. With even the toughest stand of unreinforced grasses typically failing at shear stress levels of 3.7 Ibs. per sq. ft., the SC250 more than doubles the shear resistance of any vegetation. This enables the SC250 to be used in many applications where rock riprap and concrete were once the only viable alternatives. Tech Specs I.TopNft Slba/1000 8q.H. black poij^ropyfen* ZCtwiterNet 24 lb9J1Q0Q sq. ft black polypn>p^fln» - comigated 3. Mattix Material 70% 6tiawi30% coconut 4. Bottom Net &lbs./1Q00Bq.ft. black polypropyi«no o. POFAMORO SPEC. SHEET Product Application Guide Limiting Shear Stress IbsVsq, ft. (Pascal) Permissible Velocity FPS (MPS) Product SC250 Applications 1:1 & Greater Slopes Medium to High Flow Bare Soil Vegetated 0.5 hrs 50 hrs 0.5 hrs 50 hrs Unvegetated Vegetated 9.5 (2.9) 3.0 (144) 2.5 (120) 8.0 (384) 6.0 (287) ISescription Three UV Stable Nets Top Net 5 Ib. Black Corrugated Center Net 24 Channels Ib. Black Bottom Net 5 Ib. Black 24 month grow-In ' • . • ; period ; : 70%Straw/30% ' • T - ; . ' - ' Coconut • ., Matrix Material The Vmax^ Composite Reinforcement Series SC250, 0350, and P550 is trademarlted by North Am_erican_Green, 15 (4.6) Typical Projects Roadside Ditches; Golf Course Swales; Stream Bank Protection http://www.nagreen.com/vmax3/sc250/index.htm 5/2/03 JUST ONE OF MANY DESIGN FEATURES THAT SEPARATES US FROM THE PACK... It's called an internal bypass system. The objective of stormwater treatment is to remove pollutants. That's the easy part. Tlie trick is to prevent previously captured pollutants from scouring during peak, infrequent high flows. Many systems claim they can. However, most can't. Stormceptor's patented "internal" bypass system eliminates this concern. Stormceptor's extensive lab testing, field evaluations and testimonials prove it. During normal rainfall Stormceptor removes and retains up to 80% of Total Suspended Solids and 98% of Free Oils and Hydrocarbons. Stormceplbr High flow bypass prevents scouring Rlul^ I Hydro Conduit Division 800-909-7763 • www.rinkerstormceptor,com That's an impressive statistic. Maybe that's why there are more than 11,500 Stormceptors currently in service. No other quality treatment device has been challenged more than Stormceptor, Nor has any other system been tested more. Time and again, the results have proven that Stormceptor simply works. To learn more about the . Stormceptor System and its many superior design features, simply give us a call or visit our website. Circle #66 on Reader Service Card SC250 Page 1 of 1 North American Green's SG250 is comprised of a permanent, high Strength three-dimensional matting structure incorporated with a straw/coconut fiber matrix. It is designed to provide both extended term, pre-vegetated erosion protection and permanent turf reinforcement in a wide variety of applications, including severe slopes, high flow channels and stream banks. The straw/coconut fiber matrix enhances the permanent matting's initial mulching and erosion control performance for up to 24 months. Proven in laboratory and field research, the permanent matting's high strength 3-D structure increases the shear resistance of vegetation up to 8 ibs. per sq. ft. With even the toughest stand of unreinforced grasses typically failing at shear stress levels of 3.7 Ibs. per sq. ft., the SC250 more than doubles the shear resistance of any vegetation. This enables the SC250 to be used in many applications where rock riprap and concrete were once the only viable alternatives. Tech Specs t. Top Net SIbsilOOO aq.ft. black polypropylon* 2. C«nterNet 24lba./1000fiq.ft.blsck polyprop^one - corruflBtod 3. Matrix Material 70% straw/30% coconut 4. Bottom N»t 5 ibsilOOO sq. ft. black polypropyiwie o. POF/WORO SPEC. SHEET Product Application Guide Limiting Shear Stress lbs./sq. ft. (Pascal) Permissible Velocity FPS (MPS) Product SC250 Applications Bare Soil Vegetated 0.5 hrs 50 hrs 0.5 hrs 50 hrs Unvegetated Vegetated 1:1 & Greater Slopes Medium to l-ligh Flow 3.0 (144) 2.5 (120) 8.0 (384) 6.0 (287) 9,5 (2.9) Description Three UV Stable Nets Top Net 5 Ib. Black Corrugated Center Net 24 Channels Ib. Black . Bottom Net 5 lb. Black 24 month grow-in .v V:^ " ' ^ . " • 'v /' period •••''"-'..:•'"••• ^ • -'•'- 70%Straw/30% V'- ' ' -. \ ' .'i . Coconut • • • •. Matrix Material • • . . , • , The Vmax-^ Composite Reinforcement Series SC250, C350, and P550 is trademarked by North Am_erican Green,. 15 (4.6) Typical Projects Roadside Ditches; Golf Course Swales; Stream Bank Protection http://www,nagreen.com/vmax3/sc250/index,htm 5/2/03 SR 18 Emergency Culvert Replacement Lucerne Valley, California 12' Span X 10' Rise x 68.5' Length Installed January 31, 2005 Engineer: CALTRANS UCSD Seismic Vault Pinon Flats, California 12' Span X 10' Rise x 6,98' Length (4) Installed October 25, 2004 Engineer: University of California, San Diego These structures ^re just two of over 4,000 CON/SPAN- solutions in 49 states, Canada, the Caribbean, Central & South America, and Asia, For more information, visit either the CON/SPAN-web site at www.con-span.com or the BridgeTek web site at www.bridgetek.ee 4676 Lakeview Ave. Suite 109-D Yorba Linda, CA 92886 714-777-3323 FAX: 714-695-1060 Please FAX-BACK your response to: Darwin Dizon at (714) 695-1060 or cali (714) 777-3323 to RSVP ] Yes, I wiil attend the seminar on 4/20/05. 1 No, I will not be able to attend the ^ seminar on 4/20/05. Yes, I will attend the seminar on 4/21/05. No, I will not be able to attend the seminar on 4/21/05. Meet the Team... San Diego Keynote Speaker John Robertus served 27 years on active duty as a United States Marine Corps Engineer Officer in various com- ^ mand, staff and facilities assignments, He directed environmental and natural resource programs at three Marine Corps installations on the East Coast and in Caiifomia over a 12 year period, including management of hazardous materials and wastes and oversight of compliance with discharges to the environment for solid waste, wastewater • and airborne emissions, He has sen/ed as the Executive Officer of the San Dlego Regional Water Quality Control Board since November 1995. He has a degree in Physics from the University of Califomia, an MBA from Chapman College and a Master's Degree In Nationai Security Studies from the Naval War College. Ontario Keynote Speaker Bruce Phillips, PE, is the Manager of the Stormwater Division of PACE Engineering. He is experienced in all aspects of local and regional drainage facility design for the public and private sector, including the development of drainage criteria manuals and knowledge of drainage design procedures throughout the nation. He received both his B.S. in Civil Engineering and his M.S.in Petroleum Engineering from the University of Southern California and received his M.S. in Civil Engineering Water Resources from Long Beach State University. Bruce is also a lecturer in the Civil Engineering Department at several California Universities. From BridgeTek Ed Zax is President of BridgeTek. In 1994, Ed joined BridgeTek to open its first operation in the greater Cincinnati area. Since then, BridgeTek has grown its coverage to 40 states. Ed has more than 15 years of experience directly involved with CON/SPAN®. Ed earned his B.S. and M.S. degrees in Civil Engineering from the University of Louisville. Mark Bodhaine is the Area Manager for BridgeTek's professional team for the Western United States. He has over 18 years of experience in the precast concrete industry ranging from sales, operations, and start-ups. Mark received his Bachelor of Science degree in Managerial Economics from Brigham Young University. He has been involved in the National ASTM and many local groups like NPCA, CPCA, and the NCA. Darwin Dizon, PE, Is a BridgeTek Region Manager for Southern California. He earned a Bachelor of Scienc degree in Civil Engineering from San Diego State University and is a registered P.E. in California. Darwin has over 11 years of professional experience in the environmental and construction industry Most recently he worked in the corrugated steel pipe field promoting specification work. Gina Schroer is a BridgeTek Project Consultant for Southern California. She served as the director of market- ing for an Orange County-based general contractor, and prior to relocating to Southern California, Gina was CON/SPAN- Bridge Systems' Director of Marketing from the corporate office in Dayton, Ohio. Gina earned her bachelor's degree in Communications from the University of Dayton. Kiersten Krulitz is a Project Consultant for BridgeTek Southern California. Kiersten has worked in the civil engineering industry since 2000, f'rst for Kiewit Pacific Company and most recently as a Design Engineer for Rick Engineering of San Diego. She received a bachelor's degree in Civil Engineering from the University of Idaho and Is a registered E.I.T, , . . From CON/SPAN^ Timothy Beach, PE, SE, is President of CON/SPAN® Bridge Systems. He received a B.S. degree in Civii Engineering from the University of Dayton and an M.S. degree in Civil Engineering from the University of Cincinnati. Tim is a registered engineer in 35 states and works with precasters and engineers nationwide in an effort to construct a more economical and durable bridge system. Tim is the former president of the American Society of Civil Engineers, Dayton Section, and is a member of the AASHTO Rigid Pipe Liaison Committee and ASTM C13. Philip Creamer, PE, is the regional engineer overseeing the West Coast CON/SPAN'^ office, Phil's responsi- bilities have included using the finite element program CANDE to analyze the use of CON/SPAWfor special applications. He also has extensive experience with hydraulic analyses relative to the CON/SPAN- system. He received his BS and MS degrees in Civil Engineering from the University of Kentucky. Phil is a member of ASCE. ., Scott Aston is the National Manager for CON/SPAN-'s Stormwater Systems Department and oversees the development of the Stormvault''" Mitigation System. He previously worked for Jehn & Associates, Inc. In Denver, Colorado. Scott graduated with honors from Ohio University with a Bachelor of Science degree in Civil Engineering. He is a member of ASCE, stormf^Hvault^ MITIGATION SYSTEM BY COIMUSPAN Introducing the Stormvault™ Mitigation System by CON/SPAhP Stormvault™ has emerge(d as the most effective stormwater mitigation system available today. The Stormvault™ Mitigation System provides the extremely high level of pollutant removal for which designers and municipalities throughout California have been searching. In fact, the Stormvault"^^ System is approved for use in the City and County of Sacramento because of the ability to provide a higher level of treatment than any other below-grade system. In addition, the Stormvault™ System provides for pollutant removal as good as, or better than, traditional above-ground BMPs, For additional information or for your local Stormvault™ provider, please call 877-872-7319 CON/SPAN" PRECAST VAULT UNIT TREATED EFFLUENT RETURN ENERGY BAFFLE MULTIPLE ACCESSES CONNECTOR PIPE INFLUENT PIPE • TFtAPEZOIDAL EXIT BAFFLE CONTROL ORIFICE WITH OUTLET SCREEN DIVERSION WEIR PERMANENT POOL LEVEL SEDIMENTATION BAFFLE BridgeTek 4676 Lakeview Ave. Suite 109-D Yorba Linda, CA 92886 714-777-3323 Fax. 714-695-1060 www.bridgelek.ee CON/SPA^r adge Systems lbO-526-3999 www.con-span.com provider of CONlSPAr BRIDGE SYSTEMS Technical Seminars Wednesday, April 20, 2005 Marriott Courtyard 8651 Spectmm Center Blvd. San Diego, CA 92123 858-573-0700 Thursday, April 21, 2005 Marriott-Ontario Airport 2200 E. Holt Blvd. Ontario, CA91761 909-975-5000 Hosted by Darwin Dizon and Gina Schroer PROGRAM Schedule 7:30 - 8:10 Complimentary Breakfast 8:10 - 8:15 Introductions Gina Scliroerand Kiersten Krulitz - Project Consultants, BridgeTek 8:15 - 8:35 Keynote Speakers San Diego: John Robertus - Executive Officer, San Diego Regional Water Quality Control Board Ontario: Bruce Philips - Sr. Vice President, Stormwater Management, PACE Engineenng 8:35 - 8:55 The Process Darw/n Dizon - Region Manager, BridgeTek Local Applications Gina Schroer and Kiersten Krulitz - Project Consultants, BridgeTek 8:55 • 9:05 National Applications - Transportation Ed Zax - President, BridgeTek 9:05 - 9:25 Stormwater Solutions, including the s t o r m f^l V a U11® System Scott Aston - CON/SPAhP Bridge Systems 9:25 - 9:35 Break 9:35-9:45 DOT Drainage Policies & Environmental Applications Philip Creamer, PE - CON/SPAhP Bridge Systems 9:45 • 10:00 Siting Considerations Ed Zax 10:00-10:15 Hydraulics/Foundation Types and Design Philip Creamer 10:15 -10:20 Specifications and Plan Preparation Philip Creamer 10:20 Questions & Answers Please circulate this invitation among your associates and RSVP for breakfast by calling BridgeTek at 714-777-3323, faxing your list of attendees to 714-695-1060, or e-mailing Danwin Dizon at ddi20n@bridgetek.cc Marriott Courtyard 8651 Spectrum Center Blvd. San Diego, CA 92123 858-573-0700 Map^Iint' Driving Directions: From the North: Take 5 South to 805 S, Exit Clairemont Mesa Blvd. East. Make a right onto Kearny Villa Rd, Turn left onto Spectrum Center Blvd, From the South: Take 805 N to 163 N, Exit Balboa Ave East and make a left onto Kearny Villa Rd, Make a right into Tech Way, From Downtown: 11 th Street turns into 163 N, then exit Balboa Ave East, Make a left onto Kearny Villa Rd and make a right into Tech Way, iVlarrlott-Ontario Airport 2200 E. Holt Blvd. Ontario, CA 91761 909-975-5000 Cucamonga fOntarIc R N A R D Driving Directions: From Ontario: Take Archibald North to E. Guasti Rd. Turn left and hotel is 1/2 mile on left, From Orange County/John Wayne: Take 55 Fwy N, to 5 N, to 57 N, to 10 East, Exit Vineyard Avenue, turn right. Go south for two blocks to Holt Blvd. Left onto Holt and hotel is one block down, on the right. From Los Angeles: Take 105 Fwy. E, to 605 Fwy N, to i-10 East, Exit on Vineyard, Turn left on Holt Blvd, The hotel is on the right. From San Diego: Take 15 Fwy N. to 10 Fwy West. Exit Holt Blvd. Turn left at the first light and make an immediate right into hotel parking lot. From Palm Springs: Take 10 Fwy West to Holt Blvd. Exit. Turn left at the first light, and make an immediate right into hotel parking lot. BRIDGE TECHNOLOGIES, LLC. To All BridgeTek, CON/SPAN® and Jensen Colleagues; BridgeTek Is pleased to announce the opportunity to provide the Stormvauit^'*^ Mitigation System by CON/SPAN® in California. Through our recent partnership with Jensen Precast, BridgeTek is now the exclusive provider of the Stormvault™ Mitigation System and the CON/SPAN® Bridge System in 40 states. Designers have been utilizing CON/SPAN® for their stormwater detention needs for more than 20 years. Now, by including the Stormvauit'^'^ Mitigation System treatment technology inside of CON/SPAN® structures, engineers are using CON/SPAN® for their stormwater treatment needs. The Stormvault™ Mitigation System provides the extremely high level of pollutant removal for which designers and municipalities throughout Califor- nia have been searching. In fact, the Stormvault"^^ System is approved for use in the City and County of Sacramento because of the ability to provide a higher level of treatment than any other below-grade system. In addition, the Stormvaulf^'^ System provides for pollutant removal as good as, or better than, traditional above-ground BMPs. The volume-based system also provides for flow attenuation along with the high level of treatment. As such, CON/SPAN® Stormwater Systems now provide for total volume-based stormwater management. BridgeTek's project consultants are focused on providing you with excellent customer service support on your next Stormvault'^'^ or CON/SPAN® project. We are confident that you will continue to find that CON/SPAN® and Stormvault™ are reliable and economical answers for your bridge, culvert or stormwater needs. Our team is ready to support your efforts by providing you with the best solution possible. We do hope that you can join us at our Southern California breakfast seminars in San Diego and Los Angeles on April 20 and April 21 to hear more about the Stormvault™ Mitigation System and the CON/SPAN® Bridge System. Please contact Darwin Dizon, BridgeTek's Southern California Region Manager at 714-343-3032 for reservations. Sincerely, ^^^^ -^^^ Ed Zax Timothy J. Beach President President BridgeTek CON/SPAN® 800-344-2102 www,bridgetek.cc Alabama • Alaska • Arizona • Arkansas • California • Colorado • Delaware • Florida • Georgia • Idaho • Indiana • Iowa • Kansas Kentucky • Louisiana • Maryland • Minnesota • Mississippi • Montana • Nebraska • Nevada • New Jersey • New Mexico NewYork • North Carolina • North Dakota • Ohio • Oklahoma • Oregon • Pennsylvania • South Carolina • South Dakota Tennessee • Texas • Utah • Virginia • Washington • West Virginia • Wisconsin • Wyoming SR 18 Culvert Lucerne Valley, California 12" Span x 10' Rise x 68.5' Length Installed January 31, 2005 Engineer: CALTRANS ATTACHMENT D CERTIFICATION SHEET 22 CERTIFICATION SHEET This Stormwater Management Plan has been prepared under the direction of the following Registered Civil Engineer. The Registered Civil Engineer attests to the technical information contained herein and the engineering data upon which recommendations, conclusions, and decisions are based. ADOLFO MOTA, PE DATE 15