San Joaquin Soil Series
USDA Code: CA0654
K-Factor
0.32
Soil Erodibility Factor
Texture Class
loam
Drainage Class
moderately well drained
About San Joaquin
Moderately deep soils with a hardpan, formed in alluvium from granitic rock sources. Found on low terraces and fan remnants.
K factor values are sourced from the USDA Natural Resources Conservation Service (NRCS) SSURGO database.
Using San Joaquin 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
Extensive in the eastern San Joaquin Valley. The duripan (hardpan) at 20-40 inches depth limits root penetration.
Counties Where Found
San Joaquin soil FAQ
What is the K factor for San Joaquin soil?
San Joaquin has a listed K factor of 0.32 in the Rapid RUSLE soil directory. Confirm final values against project specific soil survey data before submitting permit documents.
Where is San Joaquin soil found in California?
San Joaquin is mapped in San Joaquin, Stanislaus. County mapping is based on available soil series data and should be verified for the exact project location.
How is San Joaquin used in RUSLE erosion calculations?
Use the San Joaquin 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 San Joaquin soil data
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