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<br />1. <br /> <br />V. Dra.in.agc / Ponding <br /> <br />The permanent pool volume below me normal ~uclet shall be grcatcr than <br />or equal co me runoff from a 2.5 inch rainf.ill over the entire contributing <br />drainage: area assuming full devdopment. <br /> <br />2. <br /> <br />\ <br />The permanenr pool average depth shall be greater man or equal to four <br />fcct but less than or equal co ten feet. ! <br />[ <br /> <br />3. <br /> <br />Pond side slopes above the normal water elevacioh shail be no steeper than <br />3(horizonral): 1 (vertical). A tcn foot wide basin shelf below the normal <br />water swttce with a maximum slope racio of 1 O(horizonca.l): 1 (venica.l) is <br />ceconunendc:d to enhance wildlife habitat. reduce potential safety haurds <br />and improve access for long term maintenance. " <br /> <br />In addicion to the NURP rccommendacions for storm water trearment, the <br />pond should be designed to provide some Gctention storage. Dcrention storage <br />should be provided to reduce peak disch2rges which results in the reduccion of <br />the boWlce experienced by narural water bodies downstream and reduces flows <br />to downsw:am storm sewer systems. <br /> <br />Incorporacing the basin characteristics and the design requirements described <br />above results in a regional pond with a sur&ce area of approximately 2.1 acres <br />and a total permanent pool volume of 12.5 acre~feet. <br /> <br />Figure 14 illustrates the proposed rc:gional pond locacion :iU1d shape:. <br /> <br />Thc proposed regional pond includes approximately 0.9 acres of impaCt to <br />DNR wetland #62-50 located directly co its south. The impact area is a result <br />pond c:xcavacion and the consuuccion of an earthen berm to separate me storm <br />watcr pond &om the: existing wetland. Several meetings and discussions have <br />takcn place betwecn City staff, BRW staff. DNR reprc:scntatives. Rice Crcck <br />Watershed District staff. and the Army Corps of Enginccrs regarding the <br />proposed impaCt to DNR wetland #62-50. Impacts to DNR wcdands equal to <br />or greater than. one acre require that an Environmenca.l Assessment Worksheet <br />(FA W) be prepared prior to the grancing of :iU1y permit. The agencies involved <br />strongly recommend that the: level of impact be kept below the one acre <br />threshold in order to avoid me potencial time: ddays a.nd costs that could result <br />from the EA W process. . <br /> <br />Information regarding the proposcd regional pond has been sent to the <br />MnDOT right-oF-way staff to requesr a Limited User Permit. Howevcr, chere <br />have becn no follow-up discussions about the proje~ to datc with MnDOT <br /> <br />Twin lAiw Parltway Mast" PtJzn <br /> <br />34 <br />