Developing NRCS SNOTEL and SCAN Soil Moisture Parameters for Water Supply Forecasting Applications

Soil moisture is an important component in determining watershed hydrologic condition, and as a contribution to streamflow. Most hydrologic models use precipitation and soil climate information as surrogates for soil water holding capacity and water flow through the soil. The Natural Resources Conservation Service (NRCS) Snow Survey and Water Supply Forecasting Program has a network of installed soil moisture and soil temperature sensors in their Soil Climate Analysis Network (SCAN) and at some SNOwpack TELemetry (SNOTEL) stations throughout the U.S. The data is collected hourly at 4 to 5 soil depths at each location. Some sites have now more than 10 years of data. Soil moisture data is statistically analyzed in conjunction with other parameters in water supply forecasting. An index has been developed and tested that calculates soil moisture for a pedon using specific detailed soil and site characteristics. This method may prove to be a more comprehensive measure of soil moisture that would be applicable to a soil specific geographic area.