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HomeMy WebLinkAbout2010 11 10 Preliminary Drainage Report.pdf PRELIMINARY DRAINAGE REPORT FOR _____________ EVER VAIL ____________ VAIL, COLORADO OCTOBER 2008 Updated October 2009 Updated November 2010 PRELIMINARY DRAINAGE REPORT FOR _____________ EVER VAIL ____________ VAIL, COLORADO OCTOBER 2008 Updated October 2009 Updated November 2010 Prepared for: Vail Resorts Development Company P.O. Box 959 Avon, CO 81620 Prepared by: Alpine Engineering, Inc. P.O. Box 97 Edwards, CO 81632 (970) 926-3373 TABLE OF CONTENTS 1. Vicinity Map 2. Project Description.....................................................................................................1 3. Existing Conditions....................................................................................................1 4. Developed Conditions................................................................................................2 5. Water Quality ............................................................................................................3 6. Downstream Impact...................................................................................................3 7. Floodplain..................................................................................................................4 8. Soils............................................................................................................................4 9. Erosion and Sediment Control...................................................................................6 10. Exhibits: Exhibit A - FEMA Floodplain Map Exhibit B - Water Quality Vault Details Exhibit C - Sediment Control Details 11. Figures: Figure 1 – U.S. Soil Conservation Service Soils Map Figure 2 – U.S. Forest Service Soils Map 12. Maps Sheet 1 – Historic Drainage Area Map Sheet 2 – Developed Drainage Area Map Sheet 3 – Offsite Drainage Area Map November 2010 Preliminary Drainage Report for Ever Vail i 2. PROJECT DESCRIPTION Ever Vail is located in the west end of Lionshead in Vail, Colorado. The proposed site is 12.34 acres not including the proposed South Frontage Road. The existing commercial development is proposed to be redeveloped into a mixed-use development that will include a new gondola, office, retail, hotel and residential space and a large amount of underground parking. This report preliminarily addresses drainage issues regarding the site. 3. EXISTING CONDITIONS Red Sandstone Creek runs through the site in a north-south direction. It flows from the north under Interstate 70 through an 84” diameter corrugated metal pipe (CMP) and continues through the development site for 325 feet in an open channel to two 14- foot concrete box structures under the existing South Frontage Road. It then flows to Gore Creek for 175 feet in an open channel. Gore Creek is the southern boundary of a portion of the site. Interstate 70 is the northern boundary of the project. A portion of the development site is currently the Vail Mountain maintenance yard where snowcats and other Vail Resort’s equipment are stored and maintained and where an employee parking lot is located. There is some drainage area north of Interstate 70 that is directed to the site by a 24” CMP culvert under Interstate 70 and is diverted west in the Interstate 70 right-of-way to Red Sandstone Creek. The existing Vail Professional Building and shopping center development areas are west of Red Sandstone Creek and south of Interstate 70. Interstate 70 provides a November 2010 Preliminary Drainage Report for Ever Vail 1 drainage boundary for this portion of the proposed development although an existing 24” CMP does discharge a small drainage area from north of Interstate 70 to this area of the project. The Glen Lyon office building and associated parking exist in the southwest corner of the site. Some runoff from the Vail Professional Building and shopping center outfalls to this site and then flows to Gore Creek. There is a vacant lot that was formerly a BP gas station that fronts on Red Sandstone Creek on the west and Gore Creek on the south. This site generally does not have any offsite drainage area affecting it. 4. DEVELOPED CONDITIONS The project proposes to relocate the South Frontage Road to be adjacent and parallel to Interstate 70. Drainage from Interstate 70 will be captured by a proposed storm sewer system in the relocated South Frontage Road. Historic drainage patterns will be maintained in the developed project by generally directing drainage to Gore Creek or Red Sandstone Creek in its historic drainage pattern. The existing box culverts in the South Frontage Road at Red Sandstone Creek will be removed and allow restoration of Red Sandstone Creek in this area. A concrete arched culvert is proposed to span Red Sandstone Creek adjacent to Interstate 70 where the relocated South Frontage Road is proposed to cross Red Sandstone Creek. November 2010 Preliminary Drainage Report for Ever Vail 2 5. WATER QUALITY There are currently no known water quality devices in place on the existing development sites except at the Maintenance site where one was constructed a few years ago in conjunction with the paving of the existing employee parking lot. The proposed development site will have water quality devices to treat runoff from vehicular areas. The relocated South Frontage Road is proposed to have water quality structures adjacent to the road that will treat pollutants from the relocated South Frontage Road. One example of potential water quality vaults would be the Contech Vortechs products. Details of these vaults may be found in Appendix A. The development site itself is proposed to have parking structures underneath the majority of the project. It is expected that mechanical piping will convey surface runoff through the parking structures to Red Sandstone or Gore Creek. Therefore, water quality treatment for the site runoff would potentially be treated by a water quality device within the parking structures by the mechanical system for areas receiving vehicular traffic. A water quality structure is proposed on the west end of the Glen Lyon office building site to treat runoff from this portion of the development. The location of this structure has been shown preliminarily on the developed drainage area map. 6. DOWNSTREAM IMPACT The existing site is generally developed commercial property. The proposed development may increase impervious areas somewhat. Storm sewer outfalls will generally be diverted directly into Red Sandstone or Gore Creek. A conceptual storm November 2010 Preliminary Drainage Report for Ever Vail 3 sewer layout has been provided on Sheet 2 of the maps at the end of this report. The drainage basins for Red Sandstone and Gore Creek are quite large in comparison to the proposed development site. The peak runoff from the development site is expected to be much earlier than the overall drainage basin and would therefore not increase the peak runoff in the overall drainage basin. Therefore, detention of stormwater is not recommended for this site and no downstream impact as a result of stormwater flows from the proposed development is expected. 7. FLOODPLAIN There is a FEMA floodplain on both Gore Creek and Red Sandstone Creek. The FEMA floodplain map is included in Exhibit B of this report. Modifications to Red Sandstone Creek will include the relocated South Frontage Road crossing. The floodplain where Red Sandstone Creek will flow in the proposed concrete arched culvert and where it passes under the existing South Frontage Road in box culverts will also be revised since the box culverts will be removed. There are no floodplain impacts on Gore Creek expected as a result of the proposed development. Floodplain modeling of modifications to Red Sandstone Creek will be submitted in a separate report by others. 8. SOILS In order to assess hydrologic conditions at each of the development sites, actual soil types were obtained from the “Soil Survey of Aspen – Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties” prepared by the U.S. Department of Agriculture Soil Conservation Service and the “Draft Soil Survey of the Holy Cross Soil Survey- White River and Arapaho National Forests, Colorado – Parts of Eagle, Garfield, Mesa, November 2010 Preliminary Drainage Report for Ever Vail 4 Pitkin and Summit Counties” prepare by the U.S. Forest Service. There are four hydrologic soil groups (A, B, C, or D) that soils may be classified into as a means of estimating runoff from precipitation. They are grouped according to their runoff – producing characteristics from long-duration storms. Please refer to Figure 1 for Soils Maps and Tables 1 and 2 for soil names and hydrologic soil groups. TABLE 1 SOIL CONSERVATION SERVICE SOILS SUMMARY Map Symbol Soil Name Hydrologic Soil Type 45 Forsey B TABLE 1 U.S. FOREST SERVICE SOILS SUMMARY Map Symbol Soil Name Hydrologic Soil Type 104A Cryoborolls – Cryaquolls B - D ML Made Land All impervious Group B soils have a moderate infiltration rate and consist mainly of moderately deep or deep, moderately well drained soils that have moderately fine texture to moderately course texture. Made Land (ML) is man-made material, including buildings, pavement, fill, and other disturbed areas. It is mostly impervious. For the development site, the following soils are present: The Maintenance site consists of Made Land. It is primarily buildings and paved parking lot. There is an existing paved parking lot on the west end of the site. The Professional Buildings consists of Made Land. There are some trees along the perimeter of this site, but the majority of the site is existing parking lot. The vacant lot consists of November 2010 Preliminary Drainage Report for Ever Vail 5 Forsey soils, however there were several buildings, parking areas, and from field observation, there is a lot of man-made fill present. There are a few trees at the perimeter of this site, but no other vegetation present. The Glen Lyon office building is primarily building and paved parking. The soils are primarily Forsey and there are some landscape areas and trees on the site. 9. EROSION AND SEDIMENT CONTROL A sediment control plan will be prepared for the project to limit the transportation of sediments to Gore Creek and Red Sandstone Creek during construction. Devices that may be used during construction to prevent sediment-laden runoff from leaving the site included stabilized construction entrances, silt fence, straw bales, stone outlet structures, sediment traps and a removable pumping station. Details of these devices may be found in Exhibit C. November 2010 Preliminary Drainage Report for Ever Vail 6 EXHIBIT A FEMA FLOODPLAIN MAP EXHIBIT B WATER QUALITY VAULT DETAILS Hydrodynamic Separation Products VortSentry®VortSentry® HS page 2 page 3 High performance hydrodynamic separation The Vortechs system is a high-performance hydrodynamic separator that effectively removes fi ner sediment, oil and grease, and fl oating and sinking debris. Its swirl concentrator and fl ow controls work together to minimize turbulence and provide stable storage of captured pollutants. The design also allows for easy inspection and unobstructed maintenance access. With comprehensive lab and fi eld testing, the system delivers proven results and site-specifi c solutions. Precast models can treat peak design fl ows up to 25 cfs; cast-in-place models handle even greater fl ows. A typical system is sized to provide an 80% load reduction based on laboratory- verifi ed removal effi ciencies for varying particle size distributions such as 50-micron sediment particles. How does it work? Water enters the swirl chamber at a tangent, inducing a gentle swirling fl ow pattern and enhancing gravitational separation. Sinking pollutants stay in the swirl chamber while fl oating pollutants are stopped at the baffl e wall. Typically Vortechs systems are sized such that 80% or more of runoff through the system will be controlled exclusively by the low fl ow control. This orifi ce effectively reduces infl ow velocity and turbulence by inducing a slight backwater appropriate to the site. During larger storms, the water level rises above the low fl ow control and begins to fl ow through the high fl ow control. The layer of fl oating pollutants is elevated above the infl uent pipe, preventing re-entrainment. Swirling action increases in relation to the storm intensity, which helps prevent re-suspension. When the storm drain is fl owing at peak capacity, the water surface in the system approaches the top of the high fl ow control. The Vortechs system will be sized large enough so that previously captured pollutants are retained in the system even during these infrequent events. As a storm subsides, treated runoff decants out of the Vortechs system at a controlled rate, restoring the water level to a dry-weather level equal to the invert of the inlet and outlet pipes. The low water level facilitates easier inspection and cleaning, and signifi cantly reduces maintenance costs by reducing pump-out volume. ���������������������������������������� ���������������� �������������� ������������� ����������������� ���������� ����������� Vortechs Proven performance speeds approval process Treats peak fl ows without bypassing Flow controls reduce infl ow velocity and increase residence time Unobstructed access simplifi es maintenance Shallow system profi le makes installation easier and less expensive Very low headloss Flexible design fi ts multiple site constraints • • • • • • • Vortechs ® page 2 page 3 Patented continuous defl ection separation (CDS) technology Using patented continuous defl ective separation technology, the CDS system screens, separates and traps debris, sediment, and oil and grease from stormwater runoff. The indirect screening capability of the system allows for 100% removal of fl oatables and neutrally buoyant material without blinding. Flow and screening controls physically separate captured solids, and minimize the re-suspension and release of previously trapped pollutants. Available precast or cast-in-place, offl ine units can treat fl ows from 1 to 300 cfs. Inline units can treat up to 6 cfs, and internally bypass fl ows in excess of 50 cfs. The pollutant removal capability of the CDS system has been proven in the lab and fi eld. How does it work? Stormwater enters the CDS unit’s diversion chamber where the diversion weir guides the fl ow into the unit’s separation chamber and pollutants are removed. All fl ows up to the system’s treatment design capacity enter the separation chamber. Swirl concentration and screen defl ection forces fl oatables and solids to the center of the separation chamber where 100% of fl oatables and neutrally buoyant debris larger than the screen apertures are trapped. Stormwater then moves through the separation screen, under the oil baffl e and exits the system. The separation screen remains clog free due to continuous defl ection. During fl ow events exceeding the design capacity, the diversion weir bypasses excessive fl ows around the separation chamber, so captured pollutants will not wash out. CDS Removes sediment, trash, and free oil and grease Patented screening technology captures and retains 100% of fl oatables, including neutrally buoyant and all other material greater than the screen aperture Operation independent of fl ow Performance verifi ed through lab and fi eld testing Unobstructed maintenance access Customizable/fl exible design and multiple confi gurations available Separates and confi nes pollutants from outlet fl ow Grate inlet available Multiple screen aperture sizes available • • • • • • • • • CDS ® ��������� ���������� ���� ���������� ����������� ����������� ������ ���������� �������� ���� page 4 page 5 Hydrodynamic separation with internal bypass The VortSentry is a hydrodynamic separator with a small footprint that makes it an effective treatment option for projects where space is at a premium and effective removal of fl oating and sinking pollutants is critical. The internal bypass ensures treatment chamber velocities remain low, which improves performance and eliminates the risk of resuspension. In addition to standalone applications, the VortSentry is an ideal pretreatment device. The system is housed inside a lightweight concrete manhole structure for easy installation (often without the use of a crane) and unobstructed maintenance access. How does it work? Stormwater runoff enters the unit tangentially to promote a gentle swirling motion in the treatment chamber. As stormwater circles within the chamber, settleable solids fall into the sump and are retained. Buoyant debris and oil and grease rise to the surface and are separated from the water as it fl ows under the baffl e wall. Treated water exits the treatment chamber through a fl ow control orifi ce located behind the baffl e wall. During low-fl ow conditions all runoff is diverted into the treatment chamber by the fl ow partition. At higher fl ow rates, a portion of the runoff spills over the fl ow partition and is diverted around the treatment chamber, fi lling the head equalization chamber. This collapses the head differential between the treatment chamber and the outlet, resulting in a relatively constant fl ow rate in the treatment chamber even with a substantial increase in total fl ow through the system. This further reduces the potential for resuspension or washout of captured pollutants. ���������� ������������������������� �������������� ���������������� ������ ������������������� ��������� �������������� ��������� �������� VortSentry ® VortSentry Treatment and internal bypass in one structure Compact design ideal for congested sites Unobstructed maintenance access Round, lightweight construction for easy installation • • • • page 4 page 5 VortSentry ® HS VortSentry HS Helical fl ow pattern enhances trapping and containment of pollutants High treatment and bypass capacities Compact footprint ideal for congested sites Lightweight design easy to install Available in both inline and grate inlet confi gurations Quick manufacturing turnaround time • • • • • • Engineered performance and installation simplicity The VortSentry HS system employs a helical fl ow pattern that enhances trapping and containment of pollutants and provides effective removal of settleable solids and fl oating contaminants from urban runoff. With the ability to accept a wide range of pipe sizes, the VortSentry HS can treat and convey fl ows from small to large sites. A unique internal bypass design means higher fl ows can be diverted without the use of external bypass structures. The design of the VortSentry HS minimizes adverse velocities or turbulence in the treatment chamber. This helps to prevent the washout of previously captured pollutants even during peak conditions. The VortSentry HS is also available in a grate inlet confi guration, which is ideal for retrofi ts. How does it work? Low, reactive storm fl ows are directed into the treatment chamber through the primary inlet. The tangentially oriented downward pipe induces a swirling motion in the treatment chamber that increases capture and containment abilities. Moderate storm fl ows are directed into the treatment chamber through the secondary inlet, which allows for capture of fl oating trash and debris. The secondary inlet also provides for treatment of higher fl ows without signifi cantly increasing the velocity or turbulence in the treatment chamber. This allows for a more quiescent separation environment. Settleable solids and fl oating pollutants are captured and contained in the treatment chamber. Flow exits the treatment chamber through the outlet fl ow control, which manages the amount of fl ow that is treated and helps maintain the helical fl ow patterns developed within the treatment chamber. Flows exceeding the system’s rated treatment fl ow are diverted away from the treatment chamber by the fl ow partition. Internal diversion of high fl ows eliminates the need for external bypass structures. During bypass, the head equalizing baffl e applies head on the outlet fl ow control to limit the fl ow through the treatment chamber. This helps prevent re-suspension of previously captured pollutants. ������ �������������� ������������� ���������� ������� ������������ ������� ����� ����� �������������� ���������� ����� ����������� ����� ����������� ������ page 6 page 7 Available Models Refer to the following tables for our standard models, sizes, and treatment capacities. Drawings and specifi cations are available at contechstormwater.com. We encourage you to contact your local stormwater consultant for site-specifi c design assistance. In many cases our products can be customized to fi t your particular project’s needs. Local regulations may impact design requirements. Of f l i n e 1. Structure diameter represents the standard inside dimension of the concrete structure. Offl ine systems will require additional concrete diversion components. 2. Water Quality Flow is based on 80% removal of a particle size distribution with an average particle size of 125 microns. This fl ow also represents the maximum fl ow prior to which bypass occurs. Test results are based on use of a 2400 micron screen. Cast-in-place system are available to treat higher fl ows. Check with your local representatives for specifi cations. Notes: Systems can be sized based on a water quality fl ow (e.g. 1 inch storm) or on a net annual basis depending on the local regulatory requirement. When sizing based on a water quality storm, the required fl ow to be treated should be equal to or less than the listed water quality fl ow for the selected system. Systems sized based on a water quality storm are generally more conservatively sized. Additional particle size distributions are available for sizing purposes upon request. Depth below invert is measured to the inside bottom of the system. This depth can be adjusted to meet specifi c storage or maintenance requirements. Contact our support staff for the most cost effective sizing for your area. CDS Model Structure Typical Depth Water Quality Flow2 Screen Sump Diameter1 Below Invert 125 µm Diameter/Height Storage ft m ft m cfs L/s ft m yd3 m3 PMIU20_15 4 1.2 3.7 1.1 0.7 19.8 2.0/1.5 0.6/0.5 0.5 0.4 PMIU20_15_4 4 PMIU20_15_4 4 1.2 3.5 1.1 0.7 19.8 2.0/1.5 0.6/0.5 0.5 0.4 PMSU20_15 5 PMSU20_15 5 1.5 4.4 1.3 0.7 19.8 2.0/1.5 0.6/0.5 1.1 0.8 PMSU20_20 5 PMSU20_20 5 1.5 5.0 1.5 1.1 31.1 2.0/2.0 0.6/0.6 1.1 0.8 PMSU20_25 5 PMSU20_25 5 1.5 5.3 1.6 1.6 45.3 2.0/2.5 0.6/0.8 1.1 0.8 PMSU30_20 6 PMSU30_20 6 1.8 5.5 1.7 2.0 56.6 3.0/2.0 0.9/0.6 2.1 1.6 PMSU30_30 6 PMSU30_30 6 1.8 6.5 2.0 3.0 85.0 3.0/3.0 0.9/0.9 2.1 1.6 PMSU40_30 8 PMSU40_30 8 2.4 7.8 2.4 4.5 127.4 4.0/3.0 1.2/0.9 5.6 4.3 PMSU40_40 8 PMSU40_40 8 2.4 8.8 2.7 6.0 169.9 4.0/4.0 1.2/1.2 5.6 4.3 PSWC30_20 6 PSWC30_20 6 1.8 5.3 1.6 2.0 56.6 3.0/2.0 0.9/0.6 1.9 1.5 PSW30_30 varies PSW30_30 varies varies 6.3 1.9 3.0 85.0 3.0/3.0 0.9/0.9 5.8 4.4 PSWC30_30 6 PSWC30_30 6 1.8 6.3 1.9 3.0 85.0 3.0/3.0 0.9/0.9 2.1 1.6 PSWC40_30 7 PSWC40_30 7 2.1 7.7 2.3 4.5 127.4 4.0/3.0 1.2/0.9 1.9 1.5 PSWC40_40 7 PSWC40_40 7 2.1 8.8 2.7 6.0 169.9 4.0/4.0 1.2/1.2 1.9 1.5 PSW50_42 varies PSW50_42 varies varies 8.8 2.7 9.0 254.9 5.0/4.2 1.5/1.3 1.9 1.5 PSWC56_40 8 PSWC56_40 8 2.4 8.8 2.7 9.0 254.9 5.6/4.0 1.7/1.2 1.9 1.5 PSW50_50 varies PSW50_50 varies varies 9.5 2.9 11.0 311.5 5.0/5.0 1.5/1.5 1.9 1.5 PSWC56_53 8 PSWC56_53 8 2.4 10.1 3.1 14.0 396.4 5.6/5.3 1.7/1.6 1.9 1.5 PSWC56_68 8 PSWC56_68 8 2.4 11.8 3.6 19.0 538.0 5.6/6.8 1.7/2.1 1.9 1.5 PSWC56_78 8 PSWC56_78 8 2.4 12.8 3.9 25.0 707.9 5.6/7.8 1.7/2.4 1.9 1.5 PSW70_70 varies PSW70_70 varies varies 13.0 4.0 26.0 736.2 7.0/7.0 2.1/2.1 3.9 3.0 PSW100_60 varies PSW100_60 varies varies 11.0 3.4 30.0 849.5 10.0/6.0 3.0/1.8 6.9 5.3 PSW100_80 varies PSW100_80 varies varies 13.0 4.0 50.0 1415.8 10.0/8.0 3.0/2.4 6.9 5.3 PSW100_100 varies PSW100_100 varies varies 15.0 4.6 64.0 1812.3 10.0/10.0 3.0/3.0 6.9 5.3 In l i n e Vortechs Swirl Chamber Internal Water Quality Flow1 Peak Sediment Model Diameter Length cfs / L/s Treatment Flow2 Storage ft m ft m 50 µm 110 µm 200 µm cfs L/s yd3 m3 1000 3 0.9 9 2.7 0.21/5.9 0.59/16.7 0.98/27.8 1.6 45.3 0.7 0.5 2000 4 1.2 10 3.0 0.36/10.2 1.0/28.3 1.7/48.1 2.8 79.3 1.2 0.9 3000 5 1.5 11 3.4 0.59/16.7 1.7/48.1 2.7/76.5 4.5 127.4 1.8 1.4 4000 6 1.8 12 3.7 0.78/22.1 2.2/62.3 3.7/104.8 6.0 169.9 2.4 1.8 5000 7 2.1 13 4.0 1.1/31.1 3.1/87.8 5.2/147.2 8.5 240.7 3.2 2.4 7000 8 2.4 14 4.3 1.4/39.6 4.1/116.1 6.7/189.7 11.0 311.5 4.0 3.1 9000 9 2.7 15 4.6 1.8/51.0 5.2/147.2 8.5/240.7 14.0 396.4 4.8 3.7 11000 10 3.0 16 4.9 2.3/65.1 6.5/184.1 10.7/303.0 17.5 495.5 5.6 4.3 16000 12 3.7 18 5.5 3.3/93.4 9.3/263.3 15.3/433.2 25.0 707.9 7.1 5.4 1. Water Quality Flow is based on 80% removal for a particle size distribution (PSD) with an average particle size as listed. Particle size should be chosen based on antici- pated sediment load. 2. Peak Treatment Flow is maximum fl ow treated for each unit listed. This fl ow represents an infrequent storm event such as a 10 or 25 yr storm. Standard Vortechs System depth below invert is 3’ for all precast models. Cast-in-place system are available to treat higher fl ows. Check with your local representatives for specifi cations. page 6 page 7 * Denotes models may not be manufactured in your area. Check with your local representative for availability. 1. Water Quality Flow is based on 80% removal of a particle size distribution with an average particle size of 110 microns. This fl ow also represents the maximum fl ow prior to which bypass occurs. VortSentry Swirl Chamber Typical Depth Water Quality Flow1 Max. Size Sediment Model Diameter Below Invert 110 µm Inlet/Outlet Storage ft m ft m cfs L/s in mm yd3 m3 VS30* 3 0.9 5.8 1.8 0.26 7.4 12 300 0.8 0.6 VS40 4 1.2 7.0 2.1 0.58 16.4 18 460 1.4 1.1 VS50* 5 1.5 8.0 2.4 1.1 31.1 18 460 2.2 1.7 VS60 6 1.8 8.9 2.7 1.8 51.0 24 600 3.1 2.4 VS70* 7 2.1 9.7 3.0 2.7 76.5 30 750 4.3 3.3 VS80 8 2.4 10.1 3.1 3.9 110.4 36 600 5.6 4.3 VortSentry HS Swirl Chamber Typical Depth Water Quality Flow1 Max. Size Sediment Model Diameter Below Invert 240 µm Inlet/Outlet Storage ft m ft m cfs L/s in mm yd3 m3 HS36* 3 0.9 5.6 1.7 0.55 15.6 18 460 0.5 0.4 HS48 4 1.2 6.8 2.1 1.2 34.0 24 600 0.9 0.7 HS60* 5 1.5 8.0 2.4 2.2 62.3 30 760 1.5 1.1 HS72 6 1.8 9.2 2.8 3.7 104.8 36 900 2.1 1.6 HS84* 7 2.1 10.4 3.2 5.6 158.6 42 1050 2.8 2.1 HS96 8 2.4 11.5 3.5 8.1 229.4 48 1200 3.7 2.8 * Models may not be manufactured in your area. Check with your local representative for availability. 1. Water Quality Flow is based on 80% removal of a particle size distribution with an average particle size of 240 microns. This fl ow also represents the maximum fl ow prior to which bypass occurs. Notes: Systems can be sized based on a water quality fl ow (e.g. 1 inch storm) or on a net annual basis depending on the local regulatory requirement. When sizing based on a water quality storm, the required fl ow to be treated should be equal or less than the listed water quality fl ow for the selected system. Systems sized based on a water quality storm are generally more conservatively sized. Additional particle size distributions are available for sizing purposes upon request. Depth below invert is measured to the inside bottom of the system. This depth can be adjusted to meet specifi c storage or maintenance requirements. Contact our support staff for the most cost effective sizing for your area. Customer Support Installation CONTECH Stormwater Solutions’ products are some of the easiest to install in the industry. We provide comprehensive installation details and instructions, as well as full technical support on every project. Maintenance Maintenance of CONTECH Stormwater Solutions products is cost effective, straightforward and effi cient. We offer a complete range of services that can be tailored to your specifi c site needs. 800.925.5240 contechstormwater.com ©2007 CONTECH Stormwater Solutions CONTECH Construction Products Inc. provides site solutions for the civil engineering industry. CONTECH’s portfolio includes bridges, drainage, sanitary sewer, stormwater and earth stabilization products. For information on other CONTECH division offerings, visit contech-cpi.com or call 800.338.1122 Nothing in this catalog should be construed as an expressed warranty or an implied warranty of merchantability or fi tness for any particular purpose. See the CONTECH standard quotation or acknowledgement for applicable warranties and other terms and conditions of sale. The product(s) described may be protected by one or more of the following US patents: 5,322,629; 5,624,576; 5,707,527; 5,759,415; 5,788,848; 5,985,157; 6,027,639; 6,350,374; 6,406,218; 6,641,720; 6,511,595; 6,649,048; 6,991,114; 6,998,038; 7,186,058; related foreign patents or other patents pending. Vortechs, VortSentry, VortSentry HS, and CDS are trademarks, registered trademarks, or licensed trademarks of CONTECH Construction Products Inc. INC. Support Drawings and specifi cations are available at contechstormwater.com. Site-specifi c design support is available from our engineers. • • EXHIBIT C SEDIMENT CONTROL DETAILS FIGURES MAPS