Infiltration Hydrologic Corresponding Unified Soil Soil Textures* Rate Soil Group Classification** [inches/hour] GW - Well-graded gravel or graded gravel with sand GP Poorly gravel or poorly – Gravel, Sandy graded gravel with sand Gravel, Silty 1.6 GM - Silty gravel or silty gravel with Gravel A sand SW - Well-graded sand or well-graded sand with gravel Sand, Loamy SP Poorly graded sand or poorly – Sand, Sandy graded sand with gravel 0.8 Loam SM - sand or silty sand with gravel 0.45 Loam, Silt B MH Elastic silt or elastic silt with – Loam 0.3 sand or gravel Sandy Clay ML Silts, very fine sands, silty or – C 0.2 Loam clayey fine sands GC Clayey gravel or clayey gravel – with sand SC Clayey sand or clayey sand with – Clay Loam gravel Silty Clay CL Lean clay or lean clay with sand – Loam or gravel or gravelly lean clay D 0.06 Sandy Clay OL Organic silt or organic silt with – Clay sand or gravel or gravelly organic silt Clay Fat clay or fat clay with sand or CH – gravel or gravelly fat clay OH Organic clay or organic clay with – sand or gravel or gravelly organic clay Source: Adapted from the infiltration rates” table from the Minnesota Stormwater “Design Manual, MPCA, (January 2014). *U.S. Department of Agriculture, Natural Resources Conservation Service, 2005. National Soil Survey Handbook, title 430-VI. (Online) Available: . **ASTM standard Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System). 3.0 EROSION CONTROL Policy. It is the policy of the Board of Managers to require erosion and sediment control
Hydrologic Soil Group Soil Textures* Corresponding Unified Soil Classification** Infiltration Rate [inches/hour] A Gravel, Sandy Gravel, Silty Gravel GW - Well-graded gravel or gravel with sand GP – Poorly graded gravel or poorly graded gravel with sand GM - Silty gravel or silty gravel with sand SW - Well-graded sand or well-graded sand with gravel 1.6 Sand, Loamy Sand, Sandy Loam SP – Poorly graded sand or poorly graded sand with gravel 0.8 B Loam, Silt Loam SM - sand or silty sand with gravel 0.45 MH – Elastic silt or elastic silt with sand or gravel 0.3 C Sandy Clay Loam ML – Silts, very fine sands, silty or clayey fine sands 0.2 D Clay Loam Silty Clay Loam Sandy Clay Clay Clay GC – Clayey gravel or clayey gravel with sand SC – Clayey sand or clayey sand with gravel CL – Lean clay or lean clay with sand or gravel or gravelly lean clay OL – Organic silt or organic silt with sand or gravel or gravelly organic silt CH – Fat clay or fat clay with sand or gravel or gravelly fat clay OH – Organic clay or organic clay with sand or gravel or gravelly organic clay 0.06 Source: Adapted from the “Design infiltration rates” table from the Minnesota Stormwater Manual, MPCA, (January 2014). *U.S. Department of Agriculture, Natural Resources Conservation Service, 2005. National Soil Survey Handbook, title 430-VI. (Online) Available: . **ASTM standard Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System). 3.0 EROSION CONTROL Policy. It is the policy of the Board of Managers to require erosion and sediment control
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