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Yew Development <br />Required Volume (ft~) = Im Deryiogs surfaces (ft'') x I 0 (in) x 0 9 coefficient x 1/t2 (ft/in) <br />Redevelopment <br />Required Volume (fr'1=Impervious surfaces (fC1 x 1.0 (in) x 0.45 coefficient x 1/12 (ft/inl <br />a When UBIn~ IntlltC2tiOn f01' VOIUme reduCtlOn, the fOIIOW Ind """""' Formatted: Bullets and Numbering <br />requirements must be met <br />(1) Infiltration volumes and facility sizes shall be calculated ~ """ " Formatted: Bullets and Numbering <br />urine the appropriate hydrological soil group classification <br />and desien infiltration rate from Table 1. Select the desien <br />infiltration rate from Table 1 based on the least permeable <br />soil horizon within the first five feet below the bottom <br />elevation of the proposed infiltration BMP. <br />(~ The applicant may complete double-rind infiltrometer test ~ " ' Formatted: Bullets and Numbering <br />measurements at the proposed bottom elevation of the <br />infiltration BMP to the requirements of ASTM D338S The <br />measured infiltration rate shall be divided by the <br />appropriate correction factor selected from the Minnesota <br />Stormwater Manual This test must be completed by a <br />licensed soil scientist or en ig Weer. <br />Table I. Desi n Infiltration Rates <br />Soil Group SoilTextures ASTM Unified Soil <br />Class S mbols Rate <br /> <br /> Gravel sand sandX~n~avel, or silty G W. GP 1.63 in/hr <br />A <br />- gavel loamy sand, sandy loam GM S W, SP 0.80 in/hr <br /> SM 0.60 in/hr <br />B <br />- Loam, Silt loam ML. OL, 0.30 in/hr <br />C Sandi cla Ism GC. SC 0.20 in/hr <br />_ Clav loam silty loam, sandy 00 i <br />/h <br />0 <br />D <br />- <br />cla silt cla or cla CL, CH.OH, MFI n <br />r <br />. <br />Source' Minnesota,Slorrnwatev Manual NovernGer 200.1. <br />(31 The infiltration area shalt be capable of infiltratine the ~ " " Formatted: Bullets and Numbering ~ <br />required volume within 48 hours for surface and subsurface <br />BMPs. <br />(41 Infiltration areas shall be limited to the horizontal areas ~ Formatted: Bullets and Numbering <br />subject toprolon~ed wetting. <br />(S) Areas of permanent pools tend to lose infiltration capacity ~- Formatted: Bullets antl Numbering , <br />over time and shall not be accepted as an infiltration <br />practice. <br />