09-23-2002 Council Packet - Laserfiche WebLink

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Mr.Wytll PigtS Re CampTEKO Orono. MN August 7.2002 acres and Jhe actual Impervious in this drainage area is approximately 0.4 acres. Based on the Nufp Pond Sizing worksheet we would need 0.11 acre-feet of pond to treat this area. We are proposing to constmct a vegetative fitter strip west of the existing bituminous parking area to slow runoff and promote pollutants to infiltrate into the soil prior to entering the adjacent wetiand. This fitter strip wiii treat the new dining hail addition plus some of the existing building. This fitter strip varies in width from 30 feet to over 50 feet in some areas and maintains an 8.3% slope with deep-rooted, wet and shade tolerant vegetative material instead of grass. We have pond volume storage of 0.15 acre-feet; see attached Pond Volume Storage Worksheet. This fitter is designed to accommodate over a 2” rainfall event. We are unable to use PondNET to evaluate the % of removal of pollutants in this strip since it does not have an outlet, however based on the Minnesota Small Sites BMP Manual, studies have shown that fitter strips in agricultural areas that are made of grass and are 15’ wide can remove 50% of the nitrogen, phosphorus and sediment. The fitter strip we have designed is over double the width that has been proven effective in agricultural areas. We believe that this Is a perfect water quality Best Management Practice for this portion of the site because It slows down the runoff and traps pollutants. We are also treating an additional 0.24 acres of existing impervious. Currently, this area is highly vegetated around the wetland with sheet flow off of the adjacent parking iot to the east and the hill to the south across type B soils. We believe that with minimum grading and minimum fiil we can achieve a highly effective vegetative strip. -yVttland Protection We recently had a wetland delineation completed for this property by l^ihaug Environmental Company on August 5,2002. Based on this delineation. Wetiand #1 in the northwest comer of the site is approximately 7,826 square feet, requiring a 16.5-foot buffer zone as shown on the attached plans. Wetland #2 in the southeast comer of the site is approximately 8,770 square feet, also requiring a 16.5-foot buffer. We will install double silt fence along the wetland edge in the northwest comer of the site when the vegetative fitter is being constructed to reduce any erosion of exposed soil into the wetland. eSO BUTLER NOSTHBUIUNNO 810 FIRST AVENUE NORTH MNNEAPOUS. MN S5403 OFFICE: 812.382J0r0 FAX; 812.aSO.8077 «MWJiAdlBniultl