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for homogeneous soils. These rates not consider the effects ofsite <br /> variability and long-ternl clogging due to siltation and biomass bui(dup in <br /> the infiltration facility. <br /> Table 3.7—Recommended Infiltration Rates <br /> based on USDA Soll Textural Classlfcation. <br /> Estimated Long- <br /> *Short-Term Term(Design) <br /> I�filtration Correction Infiltration Rate <br /> Rate(inJhr) I'acYor,CF (in✓hr) <br /> Clean sandy gravels and 20 2 10�� <br /> gravclly sands(i.c.,90%of <br /> the total soil sample is <br /> retained in the#]0 sieve) <br /> Sand g 4 2*'�' <br /> l,o�ny Sand 2 4 0.5 <br /> Sandy Loam i 4 0.25 <br /> Loam 0.5 4 0.13 <br /> *From WEF/ASCE, 1995. <br /> '�*Noi recommended for treatment <br /> ***Refer to SSC-4 and SSC-6 for ireatrnent acceptability criteria <br /> Based on experience with long-term full-scale infiltration pond <br /> perforniance, Ecology's Technical Advisory Committee(TAC) <br /> recommends that the short-term infiltration rates be redaced as sho��m in <br /> Table 3.7, dividing by a correction factor of 2 to 4,depending on the soil <br /> teYtural classification. The correction factors provided in Table 3.7 <br /> represent an average degree of long-term facility maintenance, TSS <br /> reduction through pretreatment, and site variability in the subsurface <br /> conditions. Z�hese conditions might include deposits of ancient landslide <br /> debris, buried stream channels, lateral grain size variability, and other <br /> factors that aCfect homogeneity). <br /> These correction factors could be reduced, subject to the approval of the <br /> loca(jurisdiction, under the following conditioi�s: <br /> • For sites wi[h tittle soil variability, <br /> • Where there�vilf be a high degree of long-term facility maintenance, <br /> • �TVhere specific, reliable pretreatment is employed to reduce TSS <br /> entering the infiitration facility <br /> In no casc shall a correction factor less than 2.0 be used. <br /> 3-76 Volume III—Hydrologic Analysis and Flow Confro!QMPs FebR/ary 2005 <br /> �'Ll��j� A�-�- <br />