High-Resolution Soil Moisture Prediction and Validation in Densely Vegetated High-Relief Watersheds

The U.S. Forest Service–led Forest Soil Moisture Monitoring Network (FSMMN) is sponsoring a series of pilot studies to improve soil moisture monitoring in forests and rangelands. These studies are intended to address various limitations in current monitoring methodologies for high-relief and forested topographies, and to develop improved monitoring and assessment tools. 

This pilot study is being conducted in partnership with the USDA Natural Resources Conservation Service (NRCS) as part of the NRCS Dynamic Soil Survey. The study’s objective is to test spatially explicit models of soil moisture dynamics at watershed scales in two or more Forest Service experimental forests, initially at the Coweeta Hydrologic Laboratory, North Carolina, and Hubbard Brook Experimental Forest, New Hampshire. These sites have long streamflow records, and due to their historical status as Long Term Ecological Research sites, they also have a wealth of additional long-term climatic and ecological data available for validating results. The Fernow Experimental Forest (West Virginia) is another near-term target study site.

Work is currently focused on testing the Regional Hydro-Ecological Simulation System (RHESSys) model, a hydro-ecological model designed to simulate integrated water, carbon, and nutrient cycling and transport over spatially variable terrain. The research is exploring the sensitivity in the spatial and temporal dynamics of soil moisture to different model parameterizations, including incorporating NRCS soil survey data (SSURGO) and newly developed NRCS Digital Soil Mapping products. The Coweeta and Hubbard Brook study sites provide ideal historical environmental data for model parameterization and calibration. Additional soil moisture sensors will also be installed within the target watersheds to help validate model performance.

These efforts are intended to inform forest-based soil data collection efforts and, ultimately, improve the information available when setting guidelines for forest and range management actions. 

For more information, please contact Stephanie Connolly (stephanie.connolly@usda.gov).