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Home My WebLink AboutCT 05-08; STORM WATER MANAGEMENT PLAN; 2005-01-14STORM WATER MANAGEMENT PLAN FOR CARLSBAD RESEARCH CENTER City of Carlsbad Dwg No. Project No. Prepared By Partners Planning and Engineering 15938 Bernardo Center Drive San Diego, CA 92127 For Satterlie 4350 Executive Drive, suite 301 San Diego, CA 92121 January 14, 2005 Prepared By \\Server\c-drive\dwg\565\565-swmp.doc Partners Planning and Engineering 1/17/2005 TABLE OF CONTENTS INTRODUCTION Project Description............................................................................................ I.I. Hydrologic Unit Contribution................................................................... 1.2. Beneficial Use.............................................................................................. 1.2.1. Inland Surface Waters.................................................................. 1.2.2. Groundwater.................................................................................. CHARACTERIZATION OF PROJECT RUNOFF...................................... 2.1. Expected Pollutants from the Project Area............................................. 2.2. Pollutants of Concern ................................................................................ 2.3. Conditions of Concern............................................................................... MITIGATION MEASURES TO PROTECT WATER QUALITY 3.1. Construction B1\'IPs.................................................................................... 3.2. Post-construction BMPs............................................................................ 3.2.1. Site Design B1\'IPs............................................................................. 3.2.2. Source Control BMPs ..................................................................... 3.2.3. Treatment Control .......................................................................... 3.2.3.1. Fossil Filter Storm Water Filtration System................ 3.2.3.2. Biofilters (Vegetated Swales) ........................................... 3.2.4. Target Pollutants and Proposed BMPs......................................... OPERATION AND MAINTENANCE PROGRAM ..................................... 4.1. Source Control BMPs................................................................................ 4.1.1 Hazardous Material Storage.......................................................... 4.1.2 Trash Storage................................................................................... 4.1.3 Integrated Pest Management......................................................... 4.1.4 Efficient Irrigation System............................................................. 4.1.5 Inlet / Catch Basin Tiles.................................................................. 4.1.6 Good Housekeeping......................................................................... 4.2 Treatment Control BMPs......................................................................... 4.2.1 Fossil Filter'.' Storm Water Filtration System.............................. 4.2.2 Biofilters (Vegetated Swales) Prepared By \\Server\c-drive\dwg\565\565-swmpdoc Partners Planning and Engineering /17I2005 5.0 Fiscal Resources . 6.0 Conclusions.................................................................................................. ATTACHMENTS Vicinity Map Project Map Calculations Appendix Prepared By \\Server\c-drive\dwg\565\565-swmp.doc Partners Planring and Engineering 1/17/2005 INTRODUCTION The Storm Water Management Plan (SWMP) requirement is required under the City of Carlsbad's Storm Water Management and Discharge Control Ordinance. The purpose of this SWMP is to address the water quality impacts from the proposed improvements for the Carlsbad Research Center project located in the City of Carlsbad. Best Management Practices (BMPs) will be utilized to provide a long-term solution to water quality. This SWMP is also intended to ensure the effectiveness of the BMPs through proper maintenance that is based on long-term fiscal planning. The SWMP is subject to revisions as needed by the Engineer. 1. PROJECT DESCRIPTION The proposed development includes nine (9) office buildings with associated parking, landscaping and hardscape. The project site is located east of Interstate 5, west of El Camino Real and north of Palomar Airport Road and south of 5R78. Access to the site will occur off the 2 private streets (east and west of the site) off of Faraday Ave. See Attachment 'A' for Vicinity Map. 1.1 Hydrologic Unit Contribution The proposed Carlsbad Research Center project is located in the Encinas Hydrologic Area (HA 904.40) of the Carlsbad Hydrologic Unit. Runoff from the site currently follows natural drainage paths southwesterly to Faraday Ave. and ultimately to the Pacific Ocean by way of the Agua Hedionda Lagoon. Runoff from the site will be directed to one of five (5) desiltation basins spread throughout the project site. The proposed improvements will not affect the current drainage pattern. The site discharges a total of 14.5 cfs. The existing site discharge 8.8 cfs. Therefore, the site design includes detention facilities to limit the total runoff to 8.8 cfs. The outflow from each detention basin was: Basin A = 1.8 cfs, Basin B = 0.6 cfs, Basin C = 0.6 cfs, Basin E = 0.9 cfs. See Section 2 for a basin break down and Attachment C for calculations. Prepared By \\Server\c-drive\dwg\565\565-swmp.doc Partners Planning and Engineering 1/17/2005 1.2 Beneficial Uses The beneficial uses for the hydrologic unit are included in Tables 1.1 and 1.2. These tables have been extracted from the Water Quality Control Plan for the San Diego Basin. MUN - Municipal and Domestic Supply: Includes uses of water for community, military, or individual water supply systems including, but not limited to, drinking water supply. REC1 - Contact Recreation: Includes uses of water for recreational activities involving body contact with water, where ingestion of water is reasonably possible. These uses include, but are not limited to, swimming, wading, water-skiing, skin and SCUBA diving, surfing, white water activities, fishing, or use of natural hot springs. REC2 - Non-Contact Recreation: Includes the uses of water for recreation involving proximity to water, but not normally involving body contact with water, where ingestion of water is reasonably possible. These uses include, but are not limited to, picnicking, sunbathing, hiking, camping, boating, tide pool and marine life study, hunting, sightseeing, or aesthetic enjoyment in conjunction with the above activities. WARM — Warm Freshwater Habitat: Includes uses of water that support warm water ecosystems including, but not limited to, preservation or enhancement of aquatic habitats, vegetation, fish or wildlife, including invertebrates. WILD - Wildlife Habitat: Includes uses of water that support terrestrial ecosystems including, but not limited to, preservation and enhancement of terrestrial habitats, vegetation, wildlife, (e.g., mammals, birds, reptiles, amphibians, invertebrates), or wildlife water and food sources. 1.2.1 Inland Surface Waters Inland Surface waters have the following beneficial uses as shown on table 1.1 Table 1.1 Beneficial Uses for Inland Surface Waters Hydrologic - - - Unit Number (_) .< 904.40 ii ii ii -- Prepared By \\Server\c-drive\dwg\565\565-swmp.doc Partners Planning and Engineering 1/17/2005 1.2.2 Groundwater Existing beneficial uses of groundwater for the project site in the Carlsbad Hydrologic Unit (904.31) include municipal and domestic supply, agricultural supply and industrial service supply. None of these beneficial uses will be impaired or diminished due to the construction and operation of this project. Table 1.2 Beneficial Uses for Groundwater Hydrologic Unit Number 904.40 * * Excepted from Municipal x Existing Beneficial Use 0 Potential Beneficial Use Prepared By \\Server\c-drive\dwg\565\565-swmp.doc Partners Planning and Engineering 1/17/2005 2. CHARACTERIZATION OF PROJECT RUNOFF Runoff from the site currently follows natural drainage paths southwesterly to Faraday Ave and ultimately to the Pacific Ocean by way of the Agua Hedionda Lagoon. The proposed improvements will not affect the current drainage pattern. The runoff generated on-site will be directed to either curb inlets or grass-lined swales that connect to the on-site private storm drain systems. The on-site private storm drain systems connect to the future public storm drain systems by way of future drains stubbed to the property to serve the future desiltation basins. Table 2.1 identifies the hydrologic/hydraulic characteristics for each basin. See Attachment 'B' for project BMP map. See Attachment 'C' for drainage study. Table 2:1 BASIN Total Area Qioo QWQ* Existing 4.0 AC 8.8 cfs n/a Developed 4.0 AC 8.8 cfs 0.7 cfs * Based on 85 % percentile storm with 1=0.2 in/hr 2.1 Expected Discharges There was no sampling data available for the existing site condition. The following constituents are commonly found on similar developments and could affect water quality: Sediment discharge due to construction activities. Oxygen demanding substances from landscaping. Trash and debris. Nutrients from fertilizers. Pesticides from landscaping. Oil and grease from parked cars. Heavy metals from parked cars. I . Prepared By \\Server\c-drive\dwg\565\565-swmp.doc Partners Planning and Engineering 1/17/2005 2.2 Pollutants of Concern According to the California 2002 303d list published by the San Diego Regional Water Quality Control Board, the only currently listed impaired water bodies associated with the Carlsbad Hydrologic Unit are the Agua Hedionda Creek which is listed for Total Dissolved Solids and the Agua Hedionda Lagoon which is listed for Bacteria Indicators and Sedimentation I Siltation. I 2.3 Conditions of Concern The project area consists of soil group D with a minimum saturated infiltration rate of 0.06 in/hr. I See Figure 2.1 for site location and soil type. The proposed development includes nine (9) office buildings with associated parking, landscaping and hardscape. The site discharges a total of 14.5 cfs. The existing site discharge 8.8 cfs. Therefore, the site design includes detention facilities to I limit the total runoff to 8.8 cfs. The outflow from each detention basin was: Basin A = 1.8 cfs, Basin B = 0.6 cfs, Basin C = 0.6 cfs, Basin E = 0.9 cfs. The proposed project will mitigate the pollutants of concern by directing storm water runoff either through a grass-lined swale or to a I curb inlet fitted with the Fossil Filter T" Storm Water Filtration System for water quality purposes. I Prepared By \\Server\c-drive\dwg\565\565-swmp.doc Partners Planning and Engineering 1/17/2005 3.0 MITIGATION MEASURES TO PROTECT WATER QUALITY To address water quality for the project, BMPs will be implemented during construction and post-construc:ion. 3.1 Construction BMPs A detailed description of the construction BMPs has been developed with the Grading Plan Engineering. In addition to the BMPs listed on the Project Grading Plans, the following BMPs may also be used as required to the satisfaction of the City Engineer. Silt Fence • Desilting Basin Fiber Rolls • Gravel Bag Berm Street Sweeping and Vacuuming • Sandbag Barrier Storm Drain Inlet Protection • Material Delivery and Storage Stockpile Management • Spill Prevention and Control Solid Waste Management • Concrete Waste Management Stabilized Construction Entrance/Exit • Water Conservation Practices Dewateritig Operations Vehicle and Equipment Maintenance • Permanent Revegetation of all disturbed uncovered areas Erosion Control Mats and Spray-on Applications Construction BMPs for this project will be selected, constructed, and maintained so as to comply with all applicable ordinances and guidance documents. A Storm Water Pollution Prevention Plan (SWPPP) will be prepared separately to address the pollution prevention measures that will be taken during construction. - 3.2 Post-construction BMPs 3.2.1 Site Design BMPs All disturbed areas will be either paved or landscaped. There will be no areas left bare. Landscaping of the proposed limits of disturbance is also incorporated into the plans. The I landscaping will consist of both native and non-native plants. The goal is to achieve plant establishment expeditiously to reduce erosion. The irrigation system for these landscaped areas will be monitored to reduce over irrigation. Prepared By \Server\c-drive\dwg\565\565-swmp.doc Partners Planning and Engineering 1117/2005 3.2.2 Source Control BMPs All hazardous materials with the potential to contaminate urban runoff shall be placed in an enclosure such as, but not limited to, a cabinet, shed or similar structure that prevents contact with rain, runoff or spillage to the storm water conveyance system. In addition, the hazardous materials enclosure shall be protected by secondary containment structure such as berms, dikes, curbs or temporary spill containment system. The storage area shall also be paved and sufficiently impervious to contain leaks and spills, and have a roof or awning to minimize direct precipitation within the secondary containment area. Trash storage areas shall be paved with an impervious surface, designed not to allow run-on from adjoining areas and screened or walled to prevent off-site transport of trash; and contain attached lids on all trash containers that exclude rain or contain a roof or awning to minimize direct precipitation. Use of efficient irrigation systems shall be incorporated into the landscape design. Rain shutoff devices shall be employed to prevent irrigation after precipitation. In addition, the irrigation system shall be designed to meet each landscape area's specific water requirements consistent with the Carlsbad Landscape Manual. Finally, flow reducers or shutoff valves triggered by a pressure drop shall be used to control water loss in the event of broken sprinkler heads or lines. All storm water boxes (catch basins, inlets, etc) shall be stamped or stenciled with prohibitive language (e.g., "No Dumping - I Live Downstream") satisfactory to the City Engineer. The stamping or stenciling shall be located in the concrete pavement adjacent to the trench drains. If required, the stamping shall be in Spanish as well. The stamping or stenciling shall be maintained to remain legible. An additional Source Control BMP to be used on-site is good housekeeping. Good housekeeping practices that shall be utilized on site include keeping outdoor areas in a neat and orderly condition, picking up garbage left within the pavement and landscape areas. The site shall be visually inspected on a weekly basis to remove all "foreign" items including, but not limited to, landscape debris and common trash. Routine maintenance procedures for good housekeeping include removing all freshly trimmed landscape items and natural deposited items such as annual leaves and dispose off-site per governing codes. In addition, during fertilizing, herbicide or pesticide application, over spray to non-landscape areas shall not be permitted. Application shall be limited to landscape area only. All fertilizer, herbicide or pesticide shall be applied in the amount and application as provided by the manufacturer. All empty containers shall be disposed of off-site per local codes. Finally, the paved areas shall be swept as necessary using dry methods (manual sweeping, Street sweepers,. etc) to remove dust and sediment buildup. Sweeping schedule to be determined by Satterlie. 3.2.3 Treatment Control BMPs As stated in Section III.2.D of the City of Carlsbad's Standard Urban Storm Water Mitigation Plan Storm Water Standards Manual, high priority projects shall include treatment control BMPs designed to infiltrate, filter and/or treat runoff from the project footprint to one of the "Sizing Treatment Standards" listed in Table 3 of the Manual. The site design for the Carlsbad Research Prepared By \\Server\c-drive\dwg\565\565-swmp.doc Partners Planning and Engineering 1/17/2005 I Center will utilize the Fossil Filter TM Storm Water Filtration System for water quality purposes. The Fossil Filter M Storm Water Filtration System can cleanse the runoff generated by a storm I event with a rainfall intensity of 0.2 inch/hour without impeding flow (See Figure 3.1). I 3.2.3.1 Fossil Filter Storm Water Filtration System The Fossil Filter1M Storm Water Filtration System places a catch basin insert device that contains a filtering medium (a sorbent) just under the grates of the storm water system's catch basins or I just below the gutter flow line of the system's curb inlets. The water runoff flows into the inlet, through the filter where the target contaminants are removed, and then into the drainage system. I An example of Fossil Filter TM Storm Water Filtration System is shown in Figure 3.1. The system effectively filters the first flush of stormwater runoff from a storm event and provides an overflow capability sufficient to prevent the system from becoming clogged. The sorbent medium is a nonleaching inert blend of minerals that contain non-hazardous ingredients, as I defined by Federal EPA, OSHA and WHO. I 3.2.3.2 Vegetated Swales Vegetated swales are vegetated channels that receive directed flow and convey storm water. I Vegetated strips are vegetated sections of land over which storm water flows as overland sheet flow. Pollutants are removed by filtration through the grass, sedimentation, adsorption to soil particles, and infiltration through the soil. Swales are mainly effective at removing debris and I solid particles, although some dissolved constituents are removed by adsorption onto the soil. See the Project Plan (Attachment 'B') for a cross-section of the proposed vegetated swale. I 3.2.3.1.1 Appropriate Applications and Siting Constraints Vegetated swales should be considered wherever site conditions and climate allow vegetation to I be established and where flow velocities are not high enough to cause scour. Even where swales cannot be sited to accept directed sheet flow, vegetated areas provide treatment of rainfall and I reduce the overall impervious surface. Factors Affecting Preliminary Design: I Vegetated strips have two design goals: Maximize treatment Provide adequate hydraulic function for flood routing, adequate drainage and scour I prevention. Treatment is maximized by designing the flow of water through the swale to he as shallow and long as site constraints allow. No minimum dimensions are required for treatment purposes, as this could exclude swales from consideration at I some sites. Swales should also be sized as a conveyance system calculated according to City procedures for flood routing and scour. To maximize treatment efficiency, strips I should be designed to be as long (in the direction of flow) and as flat as the site will allow. No minimum lengths or maximum slopes are required for treatment purposes. The area to be used for the strip should be free of gullies or rills that can concentrate I Prepared By \\Server\c-drive\dwg\565\565-swmp.doc Partners Planning and Engineering 1/17/2005 overland flow and cause erosion. Table 3.2.1 summarizes preliminary design factors for vegetated swales. Table 3.2.1: Summary Of Bio-filtration Design Factors (Strips And Swales) Description Applications/Siting Preliminary Design Factors Swales are vegetated channels that Site conditions Swales sized as a conveyance receive and convey storm water. and climate allow system (per City of Carlsbad Strips are vegetated buffer strips vegetation to be flood routing and scour over which storm water flows as established procedures) sheet flow. Flow velocities Swales sized as a conveyance Treatment Mechanisms: not high enough to system (per City of Carlsbad Filtration through the grass cause scour flood routing and scour Sedimentation procedures) Absorption to soil particles Swale water depth as shallow Infiltration as the site will permit Pollutants removed: Strips sized as long (in Debris and solid particles direction of flow) and flat as Some dissolved constituents the site allows Strips should be free of gullies or rills No minimum dimensions or slope restrictions for treatment purposes Vegetation mix appropriate for climates and location Table 3.2.2: Criteria for Optimum Swale Performance Parameter Optimal Criteria Minimum Criteria Hydraulic Residence Time 9 minutes 5 minutes Average Flow Velocity 0.9 ft/sec Swale Width 8 ft 2 ft Swale Length 200 ft 100 ft Swale Slope 2 -6% 1% Side Slope Ratio (Horizontal: vertical) 4:1 2:1 3.2.4 Target Pollutants and Proposed BMPs Nutrients from fertilizers will be treated primarily by practicing and maintaining good housekeeping procedures and by the proposed Fossil Filter TM Storm Water Filtration System and by the vegetated swales as secondary BMPs. Prepared By \\Server\c-drive\dwg\565\565-swmp.doc Partners Planning and Engineering 1/17/2005 Trash and debris will be treated by practicing and maintaining good housekeeping procedures and by the proposed Fossil Filter'TM Storm Water Filtration System as a secondary BMP. Pesticides from landscaping will be treated by practicing and maintaining good housekeeping procedures. Sediment discharge due to construction activities will be treated by the use of silt fence, stockpile management, stabilized construction entrance/exit, erosion control mats and spray-on applications, gravel bag barriers and permanent revegetation of all disturbed uncovered areas. Oxygen demanding substances from landscaping will be treated by practicing and maintaining good housekeeping procedures. Oil and grease from parked cars will be treated by the proposed Fossil Filter""' Storm Water Filtration System and by the proposed vegetated swales. Heavy metals from parked cars will be treated by the proposed Fossil Filter'TM Storm Water Filtration System and by the proposed vegetated swales. I Prepared By \\Server\c-drive\dwg\565\565-swmp.doc Partners Planning and Engineering 1117/2005 1 4.0 OPERATION AND MAINTENANCE PROGRAM The operation and maintenance requirements for each type of BMP are as follows: 4.1 Source Control BMPs I 4.1.1 Hazardous Material Storage Hazardous materials with the potential to contaminate urban runoff shall be: I • Placed in an enclosure such as, but not limited to a cabinet, shed, or similar structure that prevents contact with rain, runoff or spillage to the storm water conveyance system. I . Protected by secondary containment structures such as berm, dikes, or curbs. . The storage shall be paved and sufficiently impervious to contain leaks and spills. I . The storage shall have a roof or awning to minimize direct precipitation within the secondary containment area. I 4.1.2 Trash Storage The operational and maintenance needs of trash storage shall be: . The trash storage area shall be paved with an impervious surface, designed not to allow I run-on from adjoining areas. . The trash storage area shall be screened or walled to prevent off-site transport of trash. I . All trash containers shall contain lids that exclude rain. 4.1.3 Integrated Pest Management I Integrated Pest Management (IPM) is an ecosystem-based pollution prevention strategy that focuses on long-term prevention of pests or their damage through a combination of techniques I such as: Biological control I . Habitat Manipulation . Modification of cultural practices 1 . Use of resistant plant varieties Pesticides are used only after monitoring indicates they are needed according to established guidelines. Pest control materials are selected and applied in a manner that minimizes risks to I human health, beneficial and non-target organisms, and the environment. The operational and maintenance needs of an integrated pest management shall be: I . Plant pest-resistant or well-adapted plant varieties such as native plants to eliminate and/or reduce the need for pesticide use in the project design. Discourage pests by modifying the site and landscape design. I Prepared By \\Server\c-drive\dwg\565\565-swmp.doc Partners Planning and Engineering 1117/2005 Preventive Maintenance Pollution prevention is the primary "first line of defense" because pollutants that are never used do not have to be controlled or treated. Educational materials shall be distributed to future site residents/tenants with the following topics: Keeping pests out of building and landscaping using barriers, screens and caulking. Physical pest elimination techniques such as weeding, squashing, trapping, washing, or pruning out pests. Relying on natural predators to eat the pests Proper use of pesticide as a last line of defense 4.1.4 Efficient Irrigation System The operational and maintenance needs of an irrigation system are: Preventive maintenance and visual inspection of all sprinkler heads and lines. Periodic testing of all irrigation stations to verify if each landscape area is getting the correct amount of water. Periodic testing of all flow reducers and/or shutoff valves to verify in good working order. Inspection Frequency The facility will be inspected and inspection visits will be completely documented: Once a month at a minimum or as directed by the City of Carlsbad. Aesthetic and Functional Maintenance Both forms of maintenance will be combined into an overall Stormwater Management System Maintenance. Aesthetic Maintenance The following activities will be included in the aesthetic maintenance program: . Broken sprinkler heads and/or lines will be repaired or replaced in a timely manner. Functional Maintenance Functional maintenance has two components: Preventive maintenance Corrective maintenance Preventive Maintenance Preventive naintenance activities to be instituted for an irrigation system include: Preventive maintenance and visual inspection of all sprinkler heads and lines. . Periodic testing of all irrigation stations to verify if each landscape area is getting the correct amount of water. Prepared By \\Server\c-drive\dwg\565\565-swmp.cjoc Partners Planning and Engineering 1/17/2005 Periodic testing of all flow reducers and/or shutoff valves to verify in good working order. Corrective Maintenance Corrective maintenance is required on an emergency or non-routine basis to correct problems and to restore the intended operation and safe function of an irrigation system. Corrective maintenance activities include: Broken sprinkler heads and/or lines will be repaired or replaced in a timely manner. General Facility Maintenance. In addition to the above elements of corrective maintenance, general corrective maintenance will address the overall irrigation system and its associated components. If corrective maintenance is being done to one component, other components will be inspected to see if maintenance is needed. 4.1.5 Inlet / Catch Basin Tiles All curb openings and concrete catch basins and curb outlets shall be adorned with tiles containing prohibitive language and/or icons to discourage illegal dumping. The legibility of the tiles will be maintained and they will be placed flush with the top of the concrete to reduce tripping by pedestrians. All tiles shall be inspected at least once a month or as directed by the local governing agency. Should the legibility of the tile be in question, then the tile shall be repaired or replaced to restore full legibility. 4.1.6 Good Housekeeping The operational and maintenance needs associated with good housekeeping are: Keep outdoor areas in a neat and orderly condition. Pick up garbage and/or animal fecal waste left within the pavement and landscape areas. Periodic sweeping of the paved areas. Removal of all freshly trimmed landscape items and natural deposited items such as annual leaves and disposal off-site per governing codes. Apply all fertilizer, herbicide or pesticide in the amount and application as provided by the manufacturer. Inspection Frequency The site will be inspected and inspection visits will be completely documented: On a weekly basis or a directed by the City of Carlsbad Aesthetic and Functional Maintenance Both forms of maintenance will be combined into an overall Stormwater Management System Maintenance. Prepared By \\Server\c-drive\dwg\565\565-swmp.doc Partners Planning and Engineering 1117/2005 Aesthetic Maintenance The following activities will be included in the aesthetic maintenance program: Keep outdoor areas in a neat and orderly condition. Pick up garbage and/or animal fecal waste left within the pavement and landscape areas. Periodic sweeping of the paved areas. Removal of all freshly trimmed landscape items and natural deposited items such as annual leaves and disposal off-site per governing codes. Weed Control. Weeds will be removed through mechanical means. Herbicide will not be used because these chemicals may impact the water quality monitoring. I Functional Maintenance Functional maintenance has two components: Preventive maintenance Corrective maintenance Preventive Maintenance Preventive maintenance activities to be instituted with good housekeeping are: Apply all fertilizer, herbicide or pesticide in the amount and application as provided by the manufacturer. Corrective Maintenance Corrective maintenance is required on an emergency or non-routine basis. Corrective maintenance activities include: General Facility Maintenance. General corrective maintenance will address the overall facility and its associated components. If corrective maintenance is being done to one component, other components will be inspected to see if maintenance is needed. Prepared By \\Server\c-drive\dwg\565\565-swmp.doc Partners Planning and Engineering 1/17/2005 4.2 Treatment Control BMPs 4.2.1 Fossil Filter TM Storm Water Filtration System The operational and maintenance needs of a Fossil Filter"' Storm Water Filtration System are: Removal of contaminants, sediments and debris from stormwater runoff. Absorption of petroleum hydrocarbons and oil-based products from stormwater runoff. Inspection Frequency The Fossil Filter TM Storm Water Filtration System will be inspected on a regular basis. The frequency of inspection would be based on pollutant loading, amount of debris, leaves, etc., and amount of runoff. The manufacturer's recommendations include no less than three inspections per year. Manufacturer guidelines for inspection frequency are: For areas with a definite rainy season: Prior to and during the rainy season. For areas subject to year-round rainfall: On a recurring (preferably scheduled) basis. For areas with winter snow and summer rain: Prior to and just after the snow season and during the summer rain season. For filters not subject to the elements (wash racks, parking garages, etc.): Inspections should be on a regular basis. Aesthetic Maintenance The parking lot will be swept on a regular basis. Sediment and debris (litter, leaves, papers, cans, etc.) within the area and especially around the drainage inlet will be collected and removed Preventive Maintenance Preventive maintenance for the FloGardTM Storm Water Filtration System will be: After broom sweeping and removal of debris around the inlet, the catch basin grate will be removed and the condition of the screens will be checked. For Hydrocarbon units with screens covering the adsorbent, the condition of the screen will be checked and the adsorbent will be inspected through the screen. If excessive silt covers the top of the adsorbent or if the adsorbent granules are more than one-half coated with a dark gray or black substance, the adsorbent will be replaced. For FloGardTM units with adsorbent pouches, the condition of the pouches will be checked and a visual inspection made of the enclosed adsorbent. If the granules are covered, the pouches will be replaced. For Flo-Gard'TM filters, which have a fabric filter body, the serviceability of the fabric will be determined and, if called for, replaced with a new one. I I Corrective Maintenance Corrective maintenance is required when the exposed adsorbent filter medium needs to be replaced. Tc replace the filter medium, the steps are: To avoid spilling the exposed adsorbent filter medium into or onto the surrounding surface, the person replacing the adsorbent should move away from the inlet and work over a large work cloth. All exposed adsorbent and collected debris must be dumped into a D.O.T.-approved container for later disposal. The method of replacing the adsorbent depends on the type of filter. For filters with removable filter cartridges, the cartridges need to be removed from the filter, the end caps removed and the exposed material poured out. The new adsorbent will be poured into the adsorbent containment area to a level about 1 '/2 inches from the top screen when the filter cartridge or filter is level. For filters with one-piece top screens, the entire filter needs to be removed to the work area, the top screen removed and the exposed material poured out. The new adsorbent will be poured into the adsorbent containment area to a level about 1 '/2 inches from the top screen when the filter cartridge or filter is level. For filters with adsorbent pouches, the pouches need to be removed and disposed of. The new adsorbent pouches are snapped into place. Disposal of Exposed Adsorbent, Debris and Trash The exposed adsorbent, debris and trash that is generated, will be properly disposed of by Satterlie.. The exposed adsorbent is non-biodegradable, non-leaching and non-carcinogenic so, with proper handling and documentation, it can be disposed of at a landfill. However, because disposal regulations vary by area, Satterlie will contact their local regulatory agency and landfill to ensure compliance with local and state environmental regulations. Hazardous Waste Suspected hazardous wastes will be analyzed to determine disposal options. Hazardous wastes generated onsite will be handled and disposed of according to applicable local, state, and federal regulations. A solid or liquid waste is considered a hazardous waste if it exceeds the criteria listed in the CCR, Title 22, Article 11. 4.2.2 Vegetated Swales The operational and maintenance needs of a vegetated swale are: U . Vegetation management to maintain adequate hydraulic functioning and to limit habitat for disease-carrying animals. 0 Animal and vector control. Periodic sediment removal to optimize performance. Trash, debris, grass trimmings, tree pruning, and leaf collection and removal to prevent obstruction of a strip and monitoring equipment. Removal of standing water, which may contribute to the development of aquatic plant communities or mosquito breeding areas. Removal of graffiti. Preventive maintenance on sampling, flow measurement, and associated BMP equipment and structures. Erosion and structural maintenance to prevent the loss of soil and maintain the performance of the swale. Inspection Frequency The facility will be inspected and inspection visits will be completely documented: Once a month at a minimum. After every large storm (after every storm monitored or those storms with more than 0.50 inch of precipitation.) On a weekly basis during extended periods of wet weather. Aesthetic and Functional Maintenance Aesthetic maintenance is important for public acceptance of storm water facilities. Functional maintenance is important for performance and safety reasons. Both forms of maintenance will be combined into an overall Storm water Management System Maintenance. Aesthetic Maintenance The following activities will be included in the aesthetic maintenance program: Graffiti Removal. Graffiti will be removed in a timely manner to improve the appearance of a strip and to discourage additional graffiti or other acts of vandalism. Grass Trimming. Trimming of grass will be done on the vegetated strip, around fences, at the inlet and outlet structures, and sampling structures. Weed Control. Weeds will be removed through mechanical means. Herbicide will not be used because these chemicals may impact the water quality monitoring. Functional Maintenance Functional maintenance has two components: Preventive maintenance Corrective maintenance Preventive Maintenance Preventive maintenance activities to be instituted at a vegetated strip are: Grass Mowing. Vegetation seed mix within the swale is designed to be kept short to maintain adequate hydraulic functioning and to limit the development of faunal habitats. Trash and Debris. During each inspection and maintenance visit to the site, debris and trash removal will be conducted to prevent the swale from being obstructed. Sediment Removal. Sediment accumulation, as part of the operation and maintenance program at a swale, will be monitored once a month during the dry season, after every large storm (0.50 inch), and monthly during the wet season. Specifically, if sediment reaches a level at or near plant height, or could interfere with flow or operation, the sediment will be removed. If accumulation of debris or sediment is determined to be the cause of decline in design performance, prompt action (i.e., within ten working days) will be taken to restore the strip to design performance standards. Actions will include using additional fill and vegetation and/or removing accumulated sediment to correct channeling or ponding. Characterization and appropriate disposal of sediment will comply with applicable local, county, state, or federal requirements. The swale will be regraded, if the flow gradient has changed, and then replanted with sod. Removal of Standing Water. Standing water must be removed if it contributes to the development of aquatic plant communities or mosquito breeding areas. Mechanical and Electronic Components. Regularly scheduled maintenance will be performed on fences, gates, locks and sampling and monitoring equipment in accordance with the manufacturers' recommendations. Electronic and mechanical components will be operated during each maintenance inspection to assure continued performance. Fertilization and Irrigation. The vegetation seed mix has been designed so that fertilization and irrigation is not necessary. Fertilizers and irrigation will not be used to maintain the vegetation. Elimination of Mosquito Breeding Habitats. The most effective mosquito control program is one that eliminates potential breeding habitats. Corrective Maintenance Corrective maintenance is required on an emergency or non-routine basis to correct problems and to restore the intended operation and safe function of a swale. Corrective maintenance activities include: Removal of Debris and Sediment. Sediment, debris, and trash, which impede the hydraulic functioning of a swale and prevent vegetative growth, will be removed and properly disposed. Temporary arrangements will be made for handling the sediments until a permanent arrangement is made. Vegetation will be re-established after sediment removal. Structural Repairs. Once deemed necessary, repairs to structural components of a swale and its inlet and outlet structures will be done within 10 working days. Qualified individuals (i.e., the designers or contractors) will conduct repairs where structural damage has occurred. Embankment and Slope Repairs. Once deemed necessary, damage to the embankments and slopes of swales will be repaired within 10 working days. Erosion Repair. Where a reseeding program has been ineffective, or where other factors have created erosive conditions (i.e., pedestrian traffic, I concentrated flow, etc.), corrective steps will be taken to prevent loss of soil and any subsequent danger to the performance of a swale. There are a number of corrective actions than can be taken. These include erosion control blankets, I riprap, sodding, or reduced flow through the area. Designers or contractors will be consulted to address erosion problems if the solution is not evident. I . Fence Repair. Repair of fences will be done within 30 days to maintain the security of the site. Elimination of Animal Burrows. Animal burrows will be filled and steps taken I to remove the animals if burrowing problems continue to occur (filling and compacting). If the problem persists, vector control specialists will be consulted regarding removal steps. This consulting is necessary as the threat of rabies in I some areas may necessitate the animals being destroyed rather than relocated. If the BMP performance is affected, abatement will begin. Otherwise, abatement will be performed annually in September. I . General Facility Maintenance. In addition to the above elements of corrective maintenance, general corrective maintenance will address the overall facility and its associated components. If corrective maintenance is being done to one I component, other components will be inspected to see if maintenance is needed. Debris and Sediment Disposal I Waste generated within the vegetated strips is ultimately the responsibility of Satterlie. Disposal of sediment, debris, and trash will comply with applicable local, county, state, and federal waste control programs. I Hazardous Waste Suspected hazardous wastes will be analyzed to determine disposal options. Hazardous I wastes generated onsite will be handled and disposed of according to applicable local, state, and federal regulations. A solid or liquid waste is considered a hazardous waste if it exceeds the criteria listed in the CCR, Title 22, Article 11. I 5.0 FISCAL RESOURCES Satterlie is aware of its responsibility to maintain all construction and post-construction BMPs to ensure they are all in good working order. They understand that as part of the discretionary project review process, the City of Carlsbad will include maintenance conditions in the permit conditions and that security may be required. In addition, Saterlie is aware that the City of Carlsbad may require them to enter into a contract with the City prior to permit issuance obliging Satterlie to maintain, repair and replace the storm water BMP as necessary into perpetuity and that security may be required. 6.0 CONCLUSIONS The proposed development of the Carlsbad Research Center should not adversely impact the beneficial uses of the Encinas Hydrologic Area (HA 904.40) of the Carlsbad Hydrologic Unit. In order to minimize water quality impacts associated with development, Satterlie will institute site design, source control and treatment control BMPs as identified in Section 3.2 of this report. The target pollutants generated by this site and the proposed BMPs to treat them area as follows: Nutrients from fertilizers will be treated primarily by practicing and maintaining good housekeeping procedures and by the proposed Fossil Filter1M Storm Water Filtration System and by the vegetated swales as secondary BMPs. Trash and debris will be treated by practicing and maintaining good housekeeping procedures and by the proposed Fossil Filter TM Storm Water Filtration System as a secondary BMP. Pesticides from landscaping will be treated by practicing and maintaining good housekeeping procedures. Sediment discharge due to construction activities will be treated by the use of silt fence, stockpile management, stabilized construction entrance/exit, erosion control mats and spray-on applications, gravel bag barriers and permanent revegetation of all disturbed uncovered areas. Oxygen demanding substances from landscaping will be treated by practicing and maintaining good housekeeping procedures. Oil and grease from parked cars will be treated by the proposed Fossil Filter T. Storm Water Filtration System and by the proposed vegetated swales. Heavy metals from parked cars will be treated by the proposed Fossil Filter1M Storm Wa:er Filtration System and by the proposed vegetated swales. Although none of the BMPs chosen are rated as having a High Removal Efficiency, Satterlie believes that it has addressed the water quality issues to the maximum extent practicable considering the size of this site and the amount of runoff generated. This Storm Water Management Plan (SWMP) 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. - Andrew J. Kann Date REGISTERED CIVIL ENGINEER ATTACHMENT A VICINITY MAP VISTA CITY OF SAN MARCOS VICINITY MAP NOT TO SCALE ATTACHMENT B PROJECT MAP .: T. i T . .z* Tq Y - 04 *Q : WV 14 I14t. '4 4 c• a 7 .1 SbA HrD 1112 I Nsbc LeC WG ALV N16 I '\\ t !P Sb , :7 ; vsc HMt -I• b4 / to ' • • •• ' • I •'q %lt Lic / 4tG AtE . ort MIC • • •'•: • - •• • Mrron LT L. Hedionda bC '12 V llca 6 I I .\ IN TA sbC ILAW It A la LeC a , "Jilo- I \ j;1 • •• I • •• I " \\ tb G LC AtC ' 0 tl.eE2 llI: Ga 3307 30 R. 5 W R. 4 W. (Joins sheet 33, Encinitas quadrangle) 1 690 000 FEET 117° 15' N in cooperation Scale 124 000 Cooperating Agencies perimenu Station. c'1auon. 1 3% 1/ 0 1 2 Miles San Diego County Planning Department )hOtography. I 1 I I San Diego Coimty Comprehensive Planning Organization 5000 4000 3000 2000 1000 0 5000 10000 Feet - I U.S. Dept. of Agriculture-Forest Service in. This map is one of a Set of 76 compiled 1969-70 by the Soil Conservaton Service. U.S. Dept. of the Interior-Bureau of Indian Affairs dinnte SAN DIEGO AREA, CALIFORNIA NO. 22 Dept. of the Navy-U.S. Marine Corps SHEET NO. 22 I I ATTACHMENT C I CALCULATIONS I I STORM DRAIN REPORT FOR Carlsbad Research Center Carlsbad, California January 14, 2005 DWG No. Prepared By: PARTNERS Planning and Engineering 15938 Bernardo Center Drive San Diego, CA 92127 (858) 376-3444 Andrew J. Kann RCE 50940 Registration Expires 9-30-2005 TABLE OF CONTENTS SITE AND PROJECT DESCRIPTION page 1 METHODOLOGY page 1 EXISTING CONDITIONS page 1 DEVELOPED CONDITIONS page 1 EXISTING RUNOFF ANALYSIS page 1 DEVELOPED RUNOFF ANALYSIS page 2 CURB INLET DESIGN AND ANALYSIS page 2 CULVERT DESIGN AND ANALYSIS page 2 CHANNEL DESIGN AND ANALYSIS page 2 DETENTION BASIN DESIGN AND ANALYSIS page 3 RESULTS AND CONCLUSIONS page 3 LIST OF FIGURES FIGURE I: VICINITY MAP page 4 FIGURE 2: PROPOSED HYDROLOGY MAP attached FIGURE 3: EXISTING HYDROLOGY MAP attached LIST OF APPENDICES Appendix 1: Runoff Coefficients Appendix 2: 100-Year Isopluvial Charts Appendix 3: Intensity - Duration Design Chart Appendix 4: Steady Uniform Flow in Open Channels Table 7-11 Appendix 5: Nomogram-Capacity, Curb Inlet at Sag Appendix 6: Handbook of Hydraulics Tables 7-4, 7-11 and 7-14 SITE AND PROJECT DESCRIPTION - This storm drain report has been prepared as part of the Development Permit submittal requirements for the development of Carlsbad Research Center. The proposed development includes nine (9) office buildings with associated parking, landscaping and hardscape. The project site is located east of Interstate 5, west of El Camino Real and north of Palomar Airport Road and south of SR 78. See Figure No. I for Vicinity Map. See Figure 2 attached at the end of this report for the proposed drainage limits. See Figure 3 attached at the end of this report for the existing drainage limits. METHODOLOGY This drainage report has been prepared in accordance with current City of Carlsbad regulations and procedures. All of the proposed pipes, curb inlets and grass-lined swales were designed to intercept and convey the 100-year storm. The Modified Rational Method was used to compute the anticipated runoff. See the attached calculations for particulars. The following references have been used in preparation of this report: County of San Diego Hydrology Manual, April, 1993. Handbook of Hydraulics, E.F. Brater & H.W. King, 6' Ed., 1976. EXISTING CONDITIONS: The project site lies within the Carlsbad Research Center north of Faraday Ave. as mass graded pad. Runoff from the site currently follows natural drainage paths southwesterly to an existing, sump inlet per drawing ______ DEVELOPED CONDITIONS: The proposed development includes nine (9) office buildings with associated parking, landscaping and hardscape. Surface runoff from the site will be directed to either inlets fitted with the Fossil Filter TM Storm Water Filtration System or grass-lined swales for water quality purposes. In addition, on-site detention facilities will be located, where required, to reduce post development flows. EXISTING RUNOFF ANALYSIS: Runoff from the site currently follows the natural drainage path southwesterly to an existing sump inlet located on site. This flow enters the onsite private storm drain system and is conveyec to the public system in Faraday Ave. DEVELOPED RUNOFF ANALYSIS: All of the proposed pipes, inlets and grass-lined swales were designed to intercept and convey the 100-year storm. The runoff coefficients for the site were based on soil group D and ultimate improvements for the proposed site. A coefficient of 0.85 was used for all Basins. All of the proposed drainage culverts will be PVC and were sized using a Manning's 'n' coefficient of 0.013. Runoff from the site will be directed to one of five (5) desiltation basins spread throughout the project site. See the attached calculations for the particulars. CURB INLET DESIGN AND ANALYSIS: The proposed curb inlets are located in a sump condition. The curb inlets were sized utilizing the "Nomogram-Capacity, Curb Inlet at Sag" assuming a 10-inch curb face with a 6.2-inch curb opening at the inlet to determine the capacity per foot of opening (Q/L) in cfs per foot. The clear opening length was then calculated using the following equation: L=Q/(QIL) where L = Length of clear opening in feet Qioo/L = Capacity per foot of opening from Nomogram To obtain the inlet length as shown on the Grading Plans for this project, one foot was added to the clear opening lengths. CULVERT DESIGN AND ANALYSIS: The storm drain culverts were sized using King's handbook (Reference 3) Table 14 to verify capacity. For circular conduits: K' = Qn/[d"(8/3)s"(1/2)J where K' = Discharge Factcr Q = Runoff Discharge (cfs) n = Manning's Coefficient d = Diameter of Conduit (ft) s = Pipe Slope (ft/ft) See the attached calculations for culvert sizing. CHANNEL DESIGN AND ANALYSIS The proposed trapezoidal grass lined channel within this project was sized using King's Handbook (Ref. 3), Table 7-11. For trapezoidal channels: K' = QnhIbA(8/3)s/*(1/2)1 where K' = Discharge Factor Runoff Discharge (cfs) n = Manning's Coefficient b = Channel Bottom Width (ft) s = Channel Slope (ft/ft) Natural, vegetated lined channels are capable of withstanding erosion for velocities up to 5 fps. DETENTION BASIN DESIGN AND ANALYSIS: The proposed, localized, on-site detention facilities were sized utilizing the single- hydrograph method. See the attached calculations for the design procedures utilized with the singl e-hydro graph method. The detention facilities for site have been designed to account for the increase in flow from the site. Basins A, B, C, D & E where sized to account for no detentions in Basins F and G. The five on-site basins join via 18" storm drain pipes. The combination of the flows for the site does not exceed the pre-developed flows. Basin A is required to have 435 cf of storage and 450 cf is provided. Basin B is required to have 1538 cf of storage and 1680 cf is provided. Basin C is required to have 2603 cf of storage and 2800 cf is provided. Basin E is required to have 1870 cf of storage and 2015 cf is provided. All detention basins are located and designed to provide a safe emergency overflow without flooding the proposed buildings or causing damage to the on-site grading or improvements. RESULTS AND CONCLUSIONS The site discharges a total of 14.5 cfs. The existing site discharge 8.8 cfs. Therefore, the site design includes detention facilities to limit the total runoff to 8.8 cfs. The outflow from each detention basin was: Basin A = 1.8 cfs, Basin B = 0.6 cfs, Basin C = 0.6 cfs, Basin E = 0.9 cfs. A Storm Water Management Plan will be prepared separately to discuss the impacts the proposed development will have on the storm water quality. The detention basins are physically designed to allow for emergency overflow without flooding any adjacent on-site building. VISTA CITY OF SAN MARCOS VICINITY MAP NOT TO SCALE APPENDIX I I RUNOFF COEFFICIENTS (RATIONAL METHOD) I DEVELOPED AREAS (URBAN) Coefficient C Soil Group I Land Use A B I .Residential: Single Family .40 .45 .50 55 I Multi-Units .45 .50 .60 .70 I Mobile Homes .45 .50 .55 .65 Rural (lots greater than 1/2 acre) .30 .35 .40 .45 I Commercial (2) I 80% Impervious .70 .75 .80 .85 Industrial (2) 90% Impervious .80 .85 .90 .95 NOTES: I )" Soil Group maps are available at the offices of the Department of Public Works. (2) Where actual conditions deviate significantly from the tabulated imperviousness values of 80% or 90%, the values given for coefficient C. may be revised by I multiplying 80% or 90% by the ratio of actual imperviousness to the tabulated imperviousness. However, in no case shall the final coefficient be less than 0.50. I For example: Consider commercial property on D soil group. Actual imperviousness = 50% I Tabulated imperviousness = 80% Revised C = 50 x 0.85 = 0.53 I 80 A-I I I APPENDIX IX — — — — — — — — — — — — — — — — — — cory OF SAN DIEGO DEPARTMENT OF SANITATION & IflA IrLb g UMf' FLOOD CONTROL NUU I LL41 Omut PRECIPI TPN '20..' ISOPLIJVlALS 10F 100-YEAR 6410UR PECIPT1tT3 I ET•S G 1U'.! iCU e \ ~'14LMLI 50 ELSI 03 'A (MAril 35 MECCA 445 SAN CL %(NTC / j • 27.5.Cc 151 _______ 30). (C3 . . 25 40 )40 33 J-AONA (N )EL MAR 20 T _ i'- ___ - 451- __________ _________ _______ _ _ 2 LCAJO lo -- - - Prrpn .-d by 201Iw 5/ U.S.DEPARTMENr0FCOMMERCE .J ;. LM'U' \ NATIONAL OCEANIC AND AT. OSPIIERSC ADMINISTRATION 'ECIAL STUDIES BRANCH. OFFICE OF II t)ROLOCY. NATIONAL WEATH E R S E R V I C E to . SA t -. / ( .••. •.iLII a -. - 301 ... I 20 - j35 • 118' 45' 30' 15' 1170 45' 30' 15' 7160 - - - - - - - - - - - - - - - - - - - D COUNTY OF SAN DIEGO EPARTMENT OF SANITATION & 100-YEAR 24410111 PRECIPITATION FLOOD CONTROL '20_'ISOPLtJl!ILS GF 100 -YEAR 24-1IOUR PRECIPITATION INEITI1S OF AN I NCH SAU 50 SAN CL MENIE 45. 60 '5'ta 0- 70 Ao 1 - 100 %S 40 o -76 Po Sec Ir 330 P .\r1 MI, ') 1) (130'\ NAT 45 1 0- 8 80 Prepa -,J by 10 IONAL OCEANIC oCi,%'C AND Al o,:,cwurnATloN ECIAL STUDIES bACIt oFFIC& 045 OF ir DIOLOGY, NATIOAI WATIIER SE RVICE SA ; - // 5O u-8OiU'!O 1 I- I I 111;" 1151 30' 16' 1 17- 1i' 3 ni INTENSTTY-DUMTIO, SIGN CHART r.TdTr.vr:J LI I•I I4IIIh•rflhi.U,I.IIrnrr•• ... i I.I•3.( nihr.1 I Equation: I 7•44 p6 D -.645 I Intensity (In. Mr. P6 6 Hr. Precipitation (In.) Duration (Mm.) .1 6.0 5. NI5.5 -h , 0 i.4.5 0 3,5 "~ N., 3.0 CD Th2.5 2.0 1.5 1.0 Directions for Application: From precipitation naps determine 6 hr. and 24 hr. amounts for the selected frequency. These maps are printed in the County Hydrology Manual (10, 5() and 100 yr. maps included in th. Design and Procedure Manual). Adjust 6 hr. precipitation (if necessary) so that it is within the range of 45% to 65% of the 24 hr. precipitation. (Hot rplicab1e to Desert) Draw a line through the point parallel to the plotted lines. This line is the intensity-duration curve for the location being analyzed. Application Form: 0) Selected Frequency /ôO yr. 1 P 6 21 in., P24. 5f %* p24 Adjusted *P 6= _________________I n. t mm. I in/hr. *Not Applicable to Desert Region 1 3) P13t 6 hr. precipitation on the rig'r.t side of the chart. 15 20 30 40 50 1 2 3 4 5 6 Minutes APPENDIX XI IV-A-14 I I STEA1)Y UNIFORM FLOW IN OPEN CHANNEL, 7-43 KI Table 7-11. Values of K' in Formula Q for Trapezoidal Channels D = depth of water b = bottom width of channel Side slopes of channel, ratio of horizontal to vertical b Ver- tical Y4-1 -1 /-1 1-1 i-if .00069 .000691.000691.00069 .00218 .00220L00221L00222 2-1 2-1 01 02 .00068 .00068 .002131.002151.002 .00069 16 .00069 .00217 .00070 .00223 .00070 .00225 03 .00414 .00419 .00423 .00426.00428.00433 00436 .00439 .00443 .00449 .04 .05 .00660 .00946 .00670 .00964 .00679 .00979 .00685 .00991 .00691 .00700.00708.00716 .01002 .01019.01033 .01047 .00723 .01060..01086 .00736 06 .0127 .0130 .0132 .0134 .0136 .0138 .0141 .0143 .0145 .0150 07 .0162 .0166 .0170 .0173 .0175 .0180 .0183 .0187 .0190 .0197 .08 .0200 .0206 .0211 .0215 .0219 .0225 .0231 .0236 .0240 .0250 .09 .0241 .0249 .0256 .0262 .0267 .0275 .0282 .0289 .0296 .0310 .10 .0284 .0294 .0304 .0311 .0318 .0329 .0339 .0348 .0353 .0376 .11 .0329 .0343 .0354 .0364 .0373 .0387 .0400 .0413 .0424 .0448 .12 .0376 .0393 .0408 .0420 .0431 .0450 .0466 .0482 .0497 .0527 .13 .0425 .0446 .0464 .0480 .0493 .0516 .0537 .0556 .0575 .0613 .14 .0476 .0502 .0524 M542 .0559 .0587 .0612 .0636 .0659 .0706 .15 .0528 .0559 .0585 .0608 .0627 .0662 .0692 .0721 .0749 .0805 .16 .0582 .0619 .0650 .0676 .0700 .0740 .0777. .0811 .0845 .0912 .17 .0638 .0680 .0716 .0748 .0775 .0823 .0866 .0907 .0947 .1026 .18 .0695 .0744 .0786 .0822 .0854 .0910 .0960 .1008 .1055 .1148 .19 .0753 .0809 .0857 .0899 .0936 .1001 .1059 .1115 .1169 .1277 .20 .0812 .0876 .0931 .0979 .1021 .1096 .1163 .1227 .1290 .1414 .21 .0873 .0945 .101 .106 .111 .120 .127, .135 .142 .156 .22 .0934 .1015 .109 .115 .120 .130 .139 .147 .155 .171 .23 .0997 .1087 .117 .124 .130 .141 .150 .160 .169 .187 .24 .1061 .1161 .125 .133 .140 .152 .163 .173 .184 .204 .25 .1125 .1236 .133 .142 .150 .163 .176 .188 .199 .222 .26 .119 .131 .142 .152 .160 .175 .189 .202 .215 .241 .27 .126 .139 .151 .162 .171 .188 .203 .218 .232 .260 .28 .132 .147 .16i) .172 .182 .201 .217 .234 .249 .281 .29 .139 .155 .170 .182 .194 .214 .232 .250 .268 .302 .30 .146 .163 .179 .193 .205 .228 .248 .267 .287 .324 .31 .153 .172 .189 .204 .218 .242 .264 .285 .306 .347 .32 .160 .180 .199 .215 .230 .256 .281 .304 .327 .371 .33 .167 .189 .209 .227 .243 .271 .298 .323 .348 .396 .34 .174 .198 .219 .238 .256 .287 .316 .343 .370 .423 .35 .181 .207 .230 .251 .269 .303 .334 .363 .392 .450 .36 .189 .216 .241 .263 .283 .319 .353 .385 .416 .478 .37 .196 .225 .252 .275 .297 .336 .372 .406 .440 .507 .38 .203 .234 .263 .288 .312 .353 .392 .429 .465 .537 .39 .211 .244 .274 .301 .326 .371 .413 .452 .491 .568 .40 .218 .253 .286 .315 .341 .389 .434 .476 .518 .600 .41 .226 .263 .297 .328 .357 .408 .456 .501 .546 .633 .42 .233 .273 .309 .342 .373 .427 .478 .526 .574 .668 .43 .241 .283 .321 .357 .389 .447 .501 .553 .603 .703 .44 .248 .293 .334 .371 .405 .467 .525 .580 .633 .740 .45 .256 .303 .346 .386 .422 .488 .549 .607 .664 .777 HEIGHT OF OPENING (h) IN FEET N (4 I a a a ii II. .111 - IIta Ii - a a I I I 0 I\aItI..IaI I 4A \ 4A CD 40 — HEIGHT OF OPENING (h) IN INCHES \ \\ 9 \ : CAPACITY PER FOOT 'OF L(NHT OF OPENING (QIL) IN CFS/FOOT ! I I I1IJT(11111111111111111'1 I IIITIJII1IIIEIIIIII1 ' 1111T1TJ1J 0 b boo 0- L ti 46 4A go a 1JSVd b N (4 ao to \ C) \ -' \ TERMS OF OF OPENING (H\) PONOED DEPTH IN HEIGHT 11111 1 1 ' I ' I • I J • V J U I • I IIVVIj I I I J 9 N t a -a a w 0 (4 N II I -4-r - p' z()m I— L z- I o 0 z I -- -n I ;J .I j. a T2 ffl m C) H0 0 or') - U) /1 z 0 C) a a ZJfl C rn w I- - HANDBOOK OF HYDRAULICS for the Solution of ilydmi ilic Engineering Problems is 1':t lu(8 of A' for CiruJar (iia:inds in (lie Formula IL (2 = L) 1CDLII of waiLer d c1itasatr of channel 1) .00 .01 .02 .0 -00007..00031 .03 .01 .05 .06 .07 :08 .09 .00074 .00138 .00222 .00328 .00-155 .00r04.0077 .1 .00067-.01118 J.Q142 .0107 .0105 .0225 .0257 .0291 .0327 .0360 . .0306 .04.18 .0402 .0537 .0585 .0o34 .0036 .0738 .0793 - .08-19 .3 .0907 .0066 .1027 .1089 .1153 .1218 :1284 .1332 .1420 (.149() .4 .1561 .1033 .1705 .1770 .1854 .1020 .2005 .2082 .21G0 .228 .5 .232 .239 .247 - .2 .263 .271 .270 .2S7 .2115 .303 .G 3 II .319 .327 .335 .3-13 .35() .358 .3t; 0 .373 .3() .7 .33 .:ft'5- .402 .409 .410 .122 .4214 .435 .-I4I .I7 .8 .153 .458 .4;3 .408 .473 .477 .481 .485 .438 .41)1 .11 .4V4 .4110 .4117 .498 .493 .498 .4UG .49-1 .4811 .483 1.0 .4(3 STEAI)V 1JYr1•oltM FLOW IN 01'E>. CIfANELS 7-35 'fable 74. For Determining the Area a of the Cross Scetion of 1 Circtihtr Coiid iiit Flowing Part ':trt Full - depth of water I) _ Lct di:tznctcro(c1inncl and C. tC tal)lllat'il v:iIti. Then a . .01 .02 .03 .04 .05 or, .07 .08 .00 .03.50 .0 .0000 .0013 .0037 .0009 .010.5 .0147 .0192 .02-12 .0204 .1 .0400 0-370 .0534 .0000 .0003 .0731) .08.11 .os.s .000i .10:11) .2 .1118 .1100 .1281 .3:165 .14-I9 .15.J5 .1023 .1711 .1 SW) .LSU() .3 .1932 .2074 .2167 .2200 .2355 .2450 .2540 .26-12 .2739 .2S36 .4 .293-1 .3 032 .3130 .3229 .3323 .3425 .3.5 27. .3027 .372 -3327- .5 .303 .403 .413 .423 .433 .443 .462 .472 .432 .6 .402 .502 .532 .521 .531 .540 .50 .sso .569 .57S .7 .587 .59t .605 .614 .623 .632 .049 .057 .000 .8 .1574 .681 .680 .097 .704 .712 .719 .72.5 .732 .733 .9 .745 .750 .756 .701 .706 .771 .773 .779 .782 .78-1 - $TIIAI)Y UNl'O1t11 FLOW IN OPEN CHANNELS 7-43 7-42 HANDBOOK OF HYDRAULICS K' Table 7-11. Values of K' in Formula Q - bllWi for IL Table 7-10. Values of K in Formula Q se - K Dsi for Trapezoidal Channels 71 Trapezoidal Channels (Concluded) D - depth of water b - bottom width of channel D depth of water b - bottom width of channel Side 81ope2 of channel, ratio of horizontal to vertical - Side slopes of channel, ratio of horicontal to vertical b .290 )'- l )-1 .817 -I 1.10 1-1 1.37 13-1 1.00 2-1 2 41 2-1 2.91 3-1 3.40 4-I 4.30 1.81 .643 1.82 .293 .540 .813 1.09 1.37 1.90 2.41 2.91 3.39 4.30 1.83 .291 .637 .810 1.09 1.37 1.00 2.41 2.90 3.39 4.35 1.8-4 .289 .634 .807 1.09 1.30 1.89 2.40 2.90 3.39 4.35 1.85 .280 .531 .804 1.08 1.30 1.89 2.40 2.90 3.38 4.34 1.80 .284 .628 .801 1.08 1.30 1.89 2.40 2.89 3.38 4.34 1.87 .282 .625 .797 1.08 1.36 1.88 2.30 2.80 3.38 4.34 1.88 .279 .522 .794 1.07 1.36 1.88 2.39 2.88 3.37 4.33 1.89 .277 .520 .791 1.07 1.35 1.88 2.39 2.88 3.37 4.33 1.90 .275 .617 .788 1.07 1.34 1.87 2.38 2.88 3.37 4.33 1.91 .273 .614 .785 1.00 L34 1.87 2.38 2,87 3.30 4.32 1.92 .270 .612 .782 1.00 1.34 1.87 2.38 2.87 3.30 4.32 1.93 .208 .509 .779 1.00 1.33 1.80 2.37 2.87 3.36 4.32 1.94 .268 .608 .770 1.05 1.33 1.80 2.37 2.88 3.36 4.31 1.05 .204 .604 .774 1.06 1.33 1.80 2.37 2.88 3.36 4.31 1.06 .262 .601 .771 1.06 1.32 1.85 2.30 2.88 3.35 4.31 1.97 .200 .429 .768 1.04 1.32 1.85 2.30 2.85 3.34 4.30 1.98 .258 .406 .765 1.04 1.32 1.85 2.36 2.85 3.34 4.30 1.99 .250 .494 .782 1.04 1.31 1.84 2.35 2.83 3.34 4.30 2.00 .254 .491 .700 1.04 1.31 1.84 2.35 2.84 3.33 4.29 2.01 .252 .489 .767 1.03 1.31 1.84 2.33 2.84 3.33 4.29 2.02 .250 .487 .754 1.03 1.30 1.83 2.34 2.84 3.33 4.29 2.03 .248 .484 .752 1.03 1.30 1.83 2.34 2.84 3.32 4.28 2.04 .247 .482 .740 1.02 1.30 1.83 2.34 2.83 3.32 4.28 2.05 .245 .480 .746 1.02 1.30 1.82 2.33 2.83 3.32 4.28 2.00 .243 .477 .744 1.02 1.29 1.82 2.33 2.83 3.31 4.28 2.07 .241 .476 .741 1.02 1.29 1.82 2.33 2.82 3.31 4.27 1.08 .239 .473 .739 1.01 1.29 1.82 2.33 2.82 3.31 4.27 2.00 .237 .471 .730 1.01 1.28 1.81 2.32 2.82 3.31 4.27 2.10 .236 .409 .734 1.01 1.28 1.81 2.32 2.81 3.30 4.26 2.11 .234 .460 .722 1.006 1.28 1.81 2.32 2.81 3.30 4.26 2.12 .232 .484 .720 1.004 1.28 1.81 2.31 2.81 3.30 4.28 2.13 .231 .482 .727 1.001 1.27 1.80 2.31 2.81 3.29 4.28 2.14 .229 .480 .724 .999 1.27 1.80 2.31 2.80 3.29 4.26 2.16 .227 .468 .722 .998 1.27 1.80 2.31 2.80 3.29 4.26 2.16 .226 .460 .720 .994 1.27 1.79 2.30 2.80 3.29 4.28 2.17 .224 .464 .718 .991 1.28 1.10 2.30 2.80 3.28 4.24 2.18 .223 .462 .715 .989 1.20 1.70 2.30 2.79 3.28 4.24 2.19 .221 .460 .713 .987 1.26 1.70 2.20 2.79 3.28 4.24 2.20 .219 .448 .711 .984 1.26 1.78 2.29 2.79 3.28 4.24 2.21 .218 .446 .700 .982 1.25 1.78 2.20 2.78 3.27 4.23 2.22 .210 .444 .708 .980 1.25 1.78 2.29 2.78 3.47 4.23 2.23 .215 .442 .704 .977 1.25 178 2.28 2.78 3.27 4.23 2.24 .213 .440 .702 .976 1.25 1.77 2.28 2.78 3.20 4.23 2.25 .212 .439 .700 .973 1.24 1,77 2.28 2.77 3.28 4.22 - .000 .001 .274 .500 .743 1.24 1.74 2.23 2.71 3.67 I .01 .00068 .00008 00060 .00009 .00009 .00009 .00009 .00009 .00070 .O0O7 .02 .00213 .00215 .00210 .00217 .00218 .00220 .00221 .00222 .00223.0022' .03 .004 14 .004 19 .00423 .004.26 . 004 28 .00433 .00430 .00430 .00443 .00440 .04 .00660 .00670 .00679 .00085 .00601 .00700 .00708 .00710 .0072.3 .0013 .05 .00040 .00904 .00979 .00091 .01002 .01010 .01633 .01047 .01000 .0108( .08 .0127.. .0130 .0132 .0134 .0130 .0138 .0141 .0143 .0145 .0150 .07 .0102 .0100 .0170 .0173 .0175 .0180. .0183 .0181 .0190 .0197 .08 .0200 .0206 .0211 .0215 .0219 .0225 .0231. .0236 .0240 .0250 .00 .0241 .0240 .0250 .0202 .0267 .0275 .0282 .0280 .0290 .0310 .10 .0284 .0204 .0304 .0311 .0318 .0329 .0330 .0348 .0368 .0376 .11 .0329 .0343 .0354 .0304 .0373 .0387 .0400 .0413 .0424 .0448 .12 .0376 .0303 .0408 .0420 .0431 .0460 .0400 .0482 .0407 .0527 .13 .0425. .0448 .0404 .0480 .0493 .0510 .0537 .0550 .0575 .0013 .14 .O47tY .0502 .0524 0542 .0559 .0587 .0012 .0630 .0650 .0700 .16 .0528 .0559 .0586 .0008 .0027 .0602 .0002 .0721 .0740 .0805 .10 .0582 .0619 .0850 .0076 .0700 .0740 .0777 .0811 .08.46 .0012 .17 .0038 .0080 .0710 .0748 .0775 .0823 .0806 .0007 .0947 .1020 .18 .0605 .0744 .0780 .0822 .0854 .0910 .00IIQ .1008 .1066 .1148 .10 .0753 .0800 .0857 .0899 .0030 .1001 .1050 .1115 .1160 .1277 .20 .0812 .0870 .0031 .0979 .1021 .1090 .1103 .1227 .1290 .1414 .21 .0873 .0945 .101 .100 .111 .120 .127 .135 .142 .160 .22 .0934 .1016 .109 .116 .120 .130 .139 .147 .153 .171 .23 .0907 .1087 .117 .124 .130 .141 .150' .100 .169 .187 .24 .1001 .1161 .125 .133 .140 .162 .103 .173 .184 .204 .26 .1125 .1230 .133 .142 .160 .103 .170., .188 .100 .222 .20 .119 .131 .142 .162 .100 .176 .180 .202 .218 .241 .27 .120 .119 .161 .102 .171 .188 .203. .218 .232 .200 .28 .132 .147 .110 .172 .182 .201 .217 .234 .249 .281 .29 .130 .188 .170 .S2 .104 .214 .232 .250 .288 .302 .30 .140 .163 .179 .193 .206 .228 .248 .207 .281 .324 .31 .153 .172 .189 .204 .218 .242 .204. .285 .306 .347 .32 .100 .180 .190 .216 .230 .250 .281 .304 .327 .371 .33 .107 .180 .209 .221 .243 .271 .208 .323 .348 .300 .34 .174 .198 .219 .238 .250 .287 .310.. .343 .370 .423 .36 .181 .207 .230 .261 .200 .303 .334 .303 .392 .460 .30 .180 .210 .241 .203 .283 .810 .353- .386 .410 .478 .37 .106 .225 .252 .276 .207 .330. .372 .406 .440 .607 .38 .203 .234 .203 .288 .312 .363 .302 .429 .405 .637 .39 .211 .244 .274 .301 .320 .371 .413 .462 .401 .508 .40 .218 .253 .286 .316 .341 .389 .434 . .476 .618 .000 .41 .220 .203 .207 .328 .357 .408 .450 .601 .640 .0.33 .42 .233 .273 .309 .342 .373 .427 .478. .620 .574 .068 .43 .241 .283 .321 .361 .380 .447 .601 .663 .003 .703 .44 .248 .203 .334 .371 .406 .4137 .626 .680 .633 .740 .45 .250 .303 .340 .380 .422 .488 .640 .007 .004 .777 HYDROLOGY SUMMARY Basin Area No. (ac) C L (ft) I S0 (ft\ft) Ti (mm) Ii (in/hr) Qi (cfs) s (%) n (ft/ft) b (ft) Travel Time in Grass Swale K' fl/b D J Area V (ft/ft) (ft) i(ac) (ft/sec) L (ft) Tt (mm) 1 Tc (mm) I (in/hr) Qf (cf) Remarks 100-yr event Existing EI4.00O.65 600 2.00 15.8 3.39 8.8 - - Sump Inlet Proposed Al 0.57 0.85 345 2.50 6.2 6.22 3.0 0.005 0.20 5.00 0.1166 0.20 1.00 6.00 0.50 90 2.99 9.15 4.82 2.3 Sump Catch Basin BlOb 0.85 170 1.50 5.1 7.00 1.2 Sump Catch Basin B2 0.27 0.85 200 1.00 6.4 6.09 1.4 Roof Drain Conf. 0.47 0.85 6.4 2.4 0.005 0.20 7.00 0.0379 0.10 0.70 5.39 0.45 154 5.76 12.16 4.01 1.6 Cl 1.11 0.85 400 1.00 9.0 4.87 4.6 0.005 0.20 7.00 0.0725 0.15 1.05 8.45 0.54 195 5.98 14.98 3.51 3.3 Sump Catch Basin Dl 0.13 0.85 150 1.00 5.5 6.68 0.7 0.005 0.20 7.00 0.0116 0.05 0.35 2.57 0.29 145 8.42 13.93 3.67 Catch Basin _Sump El O.&6--0.85 255 1.00 7.2 5.63 3.2 0.005 0.20 7.00 0.0498 0.12 0.84 6.59 0.48 115 4.00 11.18 4.23 2.41 Sump atc Basin Fl 0.15 0.85 110 1.00 5.0 7.11 0.9 0.9On-Grade 0.91 085 475 1.00 98 461 3.6 3.6 Sump Inlet Total 145 - 565-sd Page 1 HYDROLOGY AND ii17/zuuo HYDRAULIC CALCS Conn.iSub-I!Lc' CALSum_'A ) Ti f Tt Tc I QjftJ ta. K' D\d Ca iv - NOTES Point Basini Ac. CA (Ovrind) (fg) (mm) (mm) mm. in/hr cfs (Pipe) (Pipe) (n) (fps) - 100- yr event B2 027 0.85. 023 0.23 200 LOO 6.4 0.0 6.4 6.09 1.4 170.00 0.50 10 0.418 0.9 155.00 0.50 10 0.269 0.55 0.44 2.9 LBasnE 1.3 218.00 0.50 12 0.239 0.51 0.40 3.2 Basins D-& E 1.9 cfs come from hydro flow charts 65.00 0.50 12 0.349 0.64 0.53 3.6 1 Basins C, D & E 2.5 58.00 6.00 12 0.133 0.36 0.25 A8 Basins B, C, D & E 43 43.00 5.88j80M780.270i71L2 Ba sins A,B,C,D&E 565-sd Page 2 I DETENTION STORAGE COMPUTATION PROCEDURE • / SINGLE HYDROGRAPH FORM I Input Variables (Urban Conditions Six hour precipitation amount (inches) P4 2- 7 I Time of concentration (mm.) T I Coefficient of runoff C Basin area (acres) A /. 1 Computation I T, Time to peak 2.OTCKD 1C /(l + - 1.1072T ,) T, ' Time of hydrograph to begin 7-6 T3 20T, Ta I Tia Time of hydrograph to end - 20 + 1.5 T, T -J Peak flow I . Q, CIA 'Tc -7.44 P4/T°'45 - /-/6 in/hr. I Surrounding flow (Q) Depth of precipitation for 2 hours D120 w 7.44 P4/1200"5(2 ) D120 - 0.6785 P4 - /93 in. Depth of precipitation for hydrograph I D (P4T")/5.83 in. Surrounding Intensity • I - 60(D1 - D)/(120 - 2.5T) • I• - -"e in./hr. i I Q8 C13A QS 77 I Outflow Plot Hydrocrraph I and Surrounding Flow Basin Size (Natural Conditions Outflow I C — T - // /'/ mm. I I 7•44 P4/Te0h5 - -// in./hr. (6 CIA 1. Plot on Hydrograph a. Draw line from surrounding flow intercept with beginning hydrograph limb to Q I 2. Estimate volume needed for reservoir Determine preliminary reservoir dimensions Surrounding flow discharges directly through I reservoir without detaining any storage U 3. Size outlet works Outlet flow, Q. less than or equal to Q I Stay within the limits of the reservoir I 4. Rout a. Refine reservoir dimensions and/or outflow / DETENTION STORAGE COMPUTATION PROCEDURE -' ' - IZ SINGLE HYDROGRAPH FORM Input Variables (Urban Conditions) Six hour precipitation amount (inches) P6 7 Time of concentration (mm.) T Coefficient of runoff C Basin area (acres) A Time to peak /2(8 2.0TK0/(]. + K,) = 1.1072T T, Time of bydrograph to begin T2O-T T3 Time of bydrogr4h to end T5 20+l.5T, TB Peak flow QV 1Tc CIA - 4 4 P6/T°'" — L/• / in. /hr. • Qr Surrounding flow (Q) Depth of precipitation for 2 hours D120 - 7.44 P/2.200641(2 hr.) D110 - 0.6785 P6 - 19j in. Depth of precipitation for hydrograph D0 (PT" ) / 5 • 83 - / - / / in. Surrounding Intensity 60(D1 - D0)/(120 - 2.5%) is - •gg in. /hr. Qg CI,A Q1 02 Outflow C — 0 .95 T 1/- 2 mm. I - 7•44 P6/T ° - '1-1/ in./hr. QN CIA 1. Plot on Hydroqraph a. Draw line from surrounding flow intercept w i t h beginning hyd.rograph limb to Q 2. Estimate volume needed for reservoir Determine preliminary reservoir dimensions Surrounding flow discharges directly through reservoir without detaining any storage 3. Size outlet works Outlet flow, Q less than or equal to ON Stay within the limits of the reservoir 4. Rout a. Refine reservoir dimensions and/or outflow f{litv - I I I I I I I ri - 3 Tr.: I DETENTION STORAGE COMPUTATION PROCEDURE & / SINGLE HYDROGRAPH FORM I Input Variables (Urban Conditions) Six hour precipitation amount (inches) I concentration (mm.) Time of I Coefficient of runoff Basin area (acres) I Computation Time to peak 1 T, 2.OT,XD/(]. + IC,) - Time of hydrograph to begin T2O -T Time of bydrogra'ph to end I 20 + 1.5 T, Peak flow I Q, IT. CIA 744 P/Tco6U 3-/ I Surrounding flow (Q,) Depth of precipitation for 2 hours D1 , 7.44 P/1200"5(2 hr.) I' D1 - 0.6785 p - i-3 in. Depth of precipitation for hydrograph I D (1T)/5.83 /2/ in. Surrounding Intensity • Ig 60(D - DH)/(120 - 2.5T) in/ I Q-cIA Qa Plot Hvdroaraph I Outflow I Basin and Surrounding Flow Size (Natural Conditions Outflow . 0 - (;' T - /'t ?& mm. I I 7.44 P/T 0 - 7 in./hr. C44 CIA QN 1 1. Plot on Hydrograph a. Draw line from surrounding, flow intercept with beginning hydrograph limb to QH 1 2. Estimate volume needed for reservoir Determine preliminary reservoir dimensions Surrounding flow discharges directly through I reservoir without detaining any storage I 3. Size outlet works Outlet flow, Q, less than or equal to QN Stay within the limits of the reservoir 4. Rout a. Refine reservoir dimensions and/or outflow f{lttv to 2.o T: 5'o 3.qf ; DETENTION 8TORGE COMPUTATION PROCEDURE .5 4ii1 0 SINGLE HYDROGRAPH FORM Six hour precipitation amount (inches) P4 Time of concentration (mm.) T.\3 t 3 Coefficient of runoff C Basin area (acres) A Time to T peak 2.OTCKD/(1 + K,) - 1. 1072T, Time of hydrograph to begin -8 T1 -20-T T3 Time of hydrograph to end T5 20+1.5T, Peak flow Q1 CIA Qr 'Tc 7144 P4/T°5 - in. /hr.- Surrounding flow (Q) Depth of precipitation for 2 hours D120 - 7.44 P/1200"(2 hr.) D1 0.6785 P4 - 1-83 in. Depth of precipitation for hydrograph D0 (PT")/5.83 - 1. i in. Surrounding Intensity - 60(D1 - DR) f(120 - 2.5T) in. /hr. Q3 C13A Qs ;m-i144k (')iT3i Outflow C — 09 - T - /Y-3' mm. I - 7•44 P4/Tc0 - .'- in. /hr. QM CIA Q. 1. Plot on Hydrograph a. Draw line from surrounding, flow intercept with beginning hydrograph limb to Q. 2. Estimate volume needed for reservoir Determine preliminary reservoir dimensions Surrounding flow discharges directly through reservoir without detaining any storage 3. Size outlet works Outlet flow, Q less than or equal to Q Stay within the limits of the reservoir 4. Rout a. Refine reservoir dimensions and/or outflow - gkb4 T: 433 I I DETENTION 8TORAGE COMPUTATION PROCEDURE E SINGLE HYDROGRAPH FORM I Inout Variables (Urban Conditions) Six hour precipitation amount (inches) P 07' I Time of concentration (mm.) T I Coefficient of runoff C Basin area (acres) A 6'- 66 I Computation Time to peak I T - 2.0T,KD/(]. + K,) - 1.1072T T, • Time of hydrograph to begin / r- &7L Ts - 20 - T, T5 I Time of hydrograph to end T3 -20+l.5T, T5 Peak flow Q, CIA Q, I IT. 7.P/T° - 'Y-%i Surrounding flow (Q3) I Depth of precipitation for 2 hours D10 7.44 P/1200"5(2 hr.) I D120 - 0.6785 P,6 in. Depth of precipitation for hydrograph I D (PT)/5.83 - 1. c': in. Surrounding Intensity • I, - 60(D1 - D)/(120 - 2.5T) I'Is - .4y3 in/ I Plot QsC1.A Q' I Outflow flydrograDh and Surrounding Flow I Basin Size (Natural Conditions) Outflow C - Y5 T - ______ mm. I - 7.44 P/T 0?5 - ' in./hr. QNCIA QH 1. Plot on Hydrograph a. Draw line from surroundinq flow intercept with beginning hydrograph limb to QN 2. Estimate volume needed for reservoir Determine preliminary reservoir dimensions Surrounding flow discharges directly through reservoir without detaining any storage 3. Size outlet works Outlet flow, Q, less than or equal to QN Stay within the limits of the reservoir 4. Rout a. Refine reservoir dimensions and/or outflow f1lttv 30 1? 1\6 ,ø& ATTACHMENT D APPENDIX MONITORING RECORD INSPECTION DATE DATE OF STORM INSPECTOR OBSERVATIONS! RECOMMENDATIONS DATE OF MAINTENANCE FOR REPAIR! MAINTENANCE COMMENTS Signed By: Date: All amendments made to this SWMP shall be documented in this table. DATE: BY: DESCRIPTION Prepared By \Server\c-drive\dwg\565\565-swmpdoc Partners Planning and Engineering 1/17/2005 CONTACT PERSON PHONE NUMBER ALTERNATE PHONE NUMBER ALTERNATE CONTACT PERSON PHONE NUMBER Prepared By \\Server\c-drive\dwg\565\565-swmp.doc Partners Planning and Engineering 1/17/2005 IN Prepared B' \\Server\c-drive\dwg\565\565-swmp.doc Partners Planning and Engineering 1/17/2005