Overview of USDA-NRCS Erosion Prediction Technology and Conservation Resources - Land Management Operations Database and Use

Abstract

This presentation will provide a summary and background on the development of process-based soil erosion models‘ conservation resources - land management operations database (CRLMOD) utilized by the USDA Natural Resources Conservation Service (NRCS). The USDA Agricultural Research Service (ARS) and cooperators (NRCS, Forest Service, Bureau of Land Management) initiated both the Water Erosion Prediction Project (WEPP) and the Wind Erosion Prediction System (WEPS) modeling efforts in 1985. The goal was to produce a new generation of process-based erosion prediction technology for federal agencies to use for soil and water conservation planning and assessment. Process-based erosion technology provides daily simulation results using rainfall/runoff or wind events in these models (WEPP and WEPS). Both models have seven subprocess modules that include soil, climate, management, hydrology, plant growth, residue decomposition, and erosion. WEPP and WEPS can simulate any number of years in model simulation applications, but typically NRCS uses 100-year simulations for WEPP and 50-years times the number of years in the crop rotation simulations for WEPS. If runoff is predicted to occur from a storm event, WEPP calculates soil detachment, sediment transport, sediment deposition, and sediment delivery. At the end of the simulation period, summary average annual values for detachment and deposition are reported for points down a hillslope profile, and for each detachment or deposition region. Similarly, when wind erosion events are predicted to occur WEPS calculates saltation/creep, suspension, and PM10 components of eroding soil material by wind. In conjunction with ARS, NRCS has led the development of the Land Management Operations Database (LMOD) for use with the Revised Universal Soil Loss Equation Version 2 (RUSLE2) and WEPS desktop version. To improve consistency between models, LMOD was adapted to create the Conservation Resources - Land Management Operations Database (CRLMOD) for use with WEPP and WEPS. Since WEPP and WEPS are both process-based models, database consistency has been improved; operation, crop, and residue names have been synchronized. CRLMOD is also utilized for other applications, including the Field-to-Market Fieldprint® Platform. One of the primary reasons to apply the WEPP and WEPS models is to evaluate the risk of planned cropping systems on sheet and rill erosion, wind erosion, and water usage/efficiency. Model outputs include statistical summaries for runoff, water use, and erosion where benchmark conditions can be compared to alternative management systems. Conservation planners can examine the extent of these predicted values and how they depart from the average, thus providing producers and landowners a better estimate of resource protection from extreme weather offered by their chosen management system. A consistent CRLMOD database for both models is important for accurate risk statistics. NRCS and ARS are committed to continued improvement of CRLMOD for improved consistency.