Pit Soil Series
USDA Code: CA0558
K-Factor
0.28
Soil Erodibility Factor
Texture Class
clay loam
Drainage Class
poorly drained
About Pit
Deep, poorly drained soils formed in alluvium from basaltic rock sources with significant influence from basalt residuum. Montmorillonitic clay mineralogy causes strong shrink-swell. Found on basaltic plateaus and alluvial plains at 4,000–5,500 ft.
K factor values are sourced from the USDA Natural Resources Conservation Service (NRCS) SSURGO database.
Using Pit 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
One of the most extensive soils of the Modoc Plateau, mapped across large areas of Modoc and Siskiyou counties. The Pit River drainage system gives this series its name; used for range and grain farming.
Counties Where Found
Pit soil FAQ
What is the K factor for Pit soil?
Pit has a listed K factor of 0.28 in the Rapid RUSLE soil directory. Confirm final values against project specific soil survey data before submitting permit documents.
Where is Pit soil found in California?
Pit is mapped in Lassen, Modoc, Siskiyou. County mapping is based on available soil series data and should be verified for the exact project location.
How is Pit used in RUSLE erosion calculations?
Use the Pit 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 Pit soil data
Start a Rapid RUSLE project with this soil's K-factor (0.28) pre-loaded. Get accurate RUSLE erosion risk assessments in minutes.
Start a Rapid RUSLE project with this soilNo login required to preview results.