Skip Navigation

News Release

Soil Survey Covering 780,000 Acres of Critical Foothill Landscape Released to the Public

Cynthia Stiles (530) 792-5640
Jonathan Groveman (530) 792-5692

NRCS soil scientists complete long awaited survey of Calaveras and Tuolumne counties

DAVIS, Calif., October 24, 2018 – The USDA Natural Resources Conservation Service (NRCS) Soil Science Division has now published the soil survey “Central Sierra Foothills Area, Parts of Tuolumne and Calaveras Counties” (CA630). The publication concludes years of extensive research, analyzing and categorizing of data on the private lands of the two counties. 

“This soil survey provides up-to-date classification and interpretation information for a large, centrally located portion of the Sierra Nevada foothills,” says Theresa Kunch, lead soil scientist in the Sonora office. “This is the first soil survey in California to have detailed ecological site information correlated to every soil component. The soils that were discovered and the modeling techniques used will be invaluable tools for updating surrounding older surveys as well as helping our customers make informed land-use decisions.”

The soil survey, which covers the last unmapped area in the foothills, provides information helpful to local land managers, such as erosion hazard potential and plant species regeneration after wildfire. Landowners can use surveys to help manage stocking rates and prescribed grazing or local road and home site development. Scientists can also use the data to study trends such as climate change at the regional or national level. 

The survey included a detailed analysis of nearly 2,000 soil pits taken from throughout the survey area.  Permission to access and collect samples from privately held lands were integral to the success of the effort and the soil staff is grateful to the local community for allowing them to come onto their property and dig a six foot deep soil pit, collect small samples of each soil layer (or horizon), record the findings, catalog the plant species and ecology of the area, and finally, fill back in the pit and try to leave the area looking as though they had never been there.

According to Cynthia Stiles, director for NRCS Soil Survey Region 2, the publication of CA630 represents a significant step forward towards the goal of publishing soil surveys for all private lands in California. She adds that providing soil surveys for the entire nation is a primary mission goal for the soil science division and completing this is welcome progress towards that goal.

The survey is available to the public and can be found at