Millsholm Soil Series
K-Factor
0.37
Soil Erodibility Factor
Texture Class
loam
Drainage Class
well drained
About Millsholm
Shallow, well drained soils formed in residuum and colluvium derived from sandstone and shale. Bedrock within 10–20 inches of the surface. Found on moderately steep to very steep coastal hills and mountains.
K factor values are sourced from the USDA Natural Resources Conservation Service (NRCS) SSURGO database.
Using Millsholm in a RUSLE calculation
For a California construction project, use the soil K factor with rainfall erosivity, slope length and steepness, cover management, and support practice inputs. The K factor represents the soil erodibility portion of the model, so selecting the soil series that matches the site is important for defensible stormwater documentation.
In a SWPPP workflow, the practical question is not just what soil type is mapped near the project. It is whether the mapped series, K factor, and drainage assumptions match the site evidence well enough to support the RUSLE or RUSLE2 calculation.
California Distribution
Occurs on the steeper hills in Marin and Sonoma counties, often intermixed with Barnabe and Tocaloma soils on the same hillsides. Supports annual grassland and coastal scrub; severely limited for most engineering and agricultural uses.
Counties Where Found
Millsholm soil FAQ
What is the K factor for Millsholm soil?
Millsholm has a listed K factor of 0.37 in the Rapid RUSLE soil directory. Confirm final values against project specific soil survey data before submitting permit documents.
Where is Millsholm soil found in California?
Millsholm is mapped in Marin, San Mateo, Sonoma. County mapping is based on available soil series data and should be verified for the exact project location.
How is Millsholm used in RUSLE erosion calculations?
Use the Millsholm K factor as the soil erodibility input in RUSLE or RUSLE2, along with rainfall, slope, cover, and support practice factors for the site.
Calculate erosion risk with Millsholm soil data
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