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Appendix — Rule C <br />Table C1 <br />Source: Minnesota Pollution Control Agency, Minnesota Stormwater Manual. Thirty guidance <br />manuals and many other stormwater references were reviewed by the MPCA when it compiled <br />the recommended infiltration rates. All of these sources use the following studies as the basis <br />for their recommended infiltration rates: Rawls, Brakensiek and Saxton (1982); Rawls, Gimenez <br />and Grossman (1998); Bouwer and Rice (1984); and Urban Hydrology for Small Watersheds <br />(NRCS). The rates presented in this infiltration table use the information compiled from these <br />sources as well as eight years of infiltration rates collected in various infiltration practices <br />located in the South Washington Watershed District. <br />*U.S. Department of Agriculture, Natural Resources Conservation Service, 2005. National Soil <br />Survey Handbook, title 430 -VI. (Online) Available: http: / /soils.usda.gov/technical /handbook/. <br />ASTM standard D2487 -00 <br />DRAFT DOCUMENT <br />16 <br />• <br />• <br />• <br />..®.` <br />a <br />A <br />Gravel, sand, <br />sandy gravel <br />silty gravel, <br />loamy sand, <br />sandy loam <br />GW — Well- graded gravel or well - <br />graded gravel with sand <br />GP — Poorly graded gravel or poorly <br />graded gravel with sand <br />1.63 <br />GM — Silty gravel or silty gravel with <br />sand <br />SW — Well-graded sand or well - <br />graded sand with <br />gravel <br />SP — Poorly graded sand or poorly <br />graded sand with <br />Gravel <br />0.8 <br />B <br />Loam, silt <br />loam <br />SM — Silty sand or silty sand with <br />gravel 0.6 <br />0.3 <br />ML — Silt <br />OL — Organic silt or organic silt with <br />sand or gravel or <br />gravelly organic silt <br />C <br />Sandy clay <br />loam <br />GC — Clayey gravel or clayey gravel <br />with sand <br />SC — Clayey sand or clayey sand with <br />gravel <br />0.2 <br />D <br />Clay, clay <br />loam, silty <br />clay loam, <br />sandy clay, <br />silty clay <br />CL — Lean clay or lean clay with sand <br />or gravel or <br />gravelly lean clay <br />CH — Fat clay or fat clay with sand or <br />gravel or gravelly <br />fat clay <br />OH — Organic clay or organic clay with <br />sand or gravel <br />or gravelly organic clay <br />MH — Elastic silt or elastic silt with <br />sand or gravel <br />< 0.2 <br />Source: Minnesota Pollution Control Agency, Minnesota Stormwater Manual. Thirty guidance <br />manuals and many other stormwater references were reviewed by the MPCA when it compiled <br />the recommended infiltration rates. All of these sources use the following studies as the basis <br />for their recommended infiltration rates: Rawls, Brakensiek and Saxton (1982); Rawls, Gimenez <br />and Grossman (1998); Bouwer and Rice (1984); and Urban Hydrology for Small Watersheds <br />(NRCS). The rates presented in this infiltration table use the information compiled from these <br />sources as well as eight years of infiltration rates collected in various infiltration practices <br />located in the South Washington Watershed District. <br />*U.S. Department of Agriculture, Natural Resources Conservation Service, 2005. National Soil <br />Survey Handbook, title 430 -VI. (Online) Available: http: / /soils.usda.gov/technical /handbook/. <br />ASTM standard D2487 -00 <br />DRAFT DOCUMENT <br />16 <br />• <br />• <br />• <br />