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HomeMy WebLinkAboutWPO200600064 Calculations (2) illigh.41WirrLECH. 0,4101 r Sizing Summary SOLUTIONS- Poplar Glen Phase 2 Stormwater Treatment System/Design Summary Charlottesville, VA Information provided: • Total contributing area = 1.41 acres • Impervious Area = 1.41 acres • Presiding agency =VDCR Assumptions: • Design storm = Modified Rational method • Rainfall intensity= 0.35in/hr(currently accepted by the VDCR) • Media = Zeolite/Perlite/GAC (50% TP removal credit) • Drop required from inlet to outlet= 2.3' minimum • Depth required from rim to outlet= 5.5' minimum Size estimates: The Stormwater Management StormFilter®is a passive, siphon-actuated,flow-through stormwater filtration system consisting of a structure that houses rechargeable, media-filled filter cartridges. The StormFilter works by passing stormwater through the media-filled cartridges,which trap particulates and adsorb pollutants such as dissolved metals, nutrients, and hydrocarbons. The StormFilter system is VDCR verified and as a result has received approval for 80%TSS and 50%TP removal. The StormFilter is a flow-based system, and therefore, is sized by calculating the peak water quality flow rate associated with the design storm. The water quality flow rate was calculated using the Modified Rational Method assuming a rainfall intensity of 0.35 inches per hour. Given the information above the treatment flow rate was determined to be: Qtreat =CiA = 0.90 x 0.35 x1.41 = 0.44cfs N g es = 1 /caQtreat x 449 gp/fs _ 0.44 x 449 =13.3 4 use 14 cartridges cartrid /cartridge 15 To accommodate a treatment flow rate or 0.24cfs, CONTECH Stormwater Solutions recommends using an 8' x 16' precast StormFilter with 14 cartridges (see attached detail). The estimated cost of this system, complete and delivered to the job site, is available upon request. This estimate assumes that the vault is less than 6'feet deep. The final system cost will depend on the actual depth of the units and whether extras like doors rather than castings are specified. The contractor is responsible for setting the StormFilter vault and all external plumbing. Maintenance The StormFilter requires regular maintenance to operate effectively. The expected maintenance interval for systems in Maryland is 12-18 months, but may vary depending on weather and site conditions. CONTECH Stormwater Solutions Inc. offers full maintenance services to all of our clients, as well as a cartridge exchange program to facilitate owner provided maintenance. Please contact CONTECH Stormwater Solutions or navigate to contechstormwater.com for more information in this regard. ©2006 CONTECH Stormwater Solutions 521 Progress Drive,Suite H,Linthicum,MD 21090 TS-8025 contechstormwater.com Toll-free:866.740.3318 Fax:866.376.8511