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Title: WEPS NRCS implementation issues: resolved

item Wagner, Larry

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 7/15/2011
Publication Date: 9/1/2011
Citation: Wagner, L.E. 2011. WEPS NRCS implementation issues: resolved. In: Proceedings International Symposium on Erosion and Landscape Evolution (ISELE), 18-21 September 2011, Anchorage, Alaska. ISELE Paper No. 11033. D.C. Flanagan, J.C. Ascough II, and J.L Nieber (eds.). St. Joseph, MI ASABE.

Interpretive Summary:

Technical Abstract: The Wind Erosion Prediction System (WEPS) is a process based, daily time step, wind erosion model. In response to NRCS needs for improved wind erosion technology, WEPS was conceived to replace the empirical Wind Erosion Equation (WEQ), first released in 1967. WEPS was designed to better reflect management effects on the susceptibility of soil to wind erosion. Besides providing predictions on long-term annual soil loss from cropland fields, WEPS can provide estimates by particulate size (creep/saltation, suspension and PM10) leaving the simulation site, the impact of wind barriers and changes in surface conditions created by different management practices. It reflects the daily changes due to weather on surface roughness and wetness, residue decomposition and plant growth, therefore reflecting the overall impact of weather variations on a site’s susceptibility to wind erosion. USDA-NRCS (Natural Resources Conservation Service) is in the process of implementing WEPS as a replacement for WEQ within their agency. As such, they required databases for daily weather inputs (precipitation, temperature, solar radiation, etc.), hourly wind speeds, soil and management practices to run the model anywhere in the U.S. on agricultural cropland. In addition, national database records for all prominent crops and operations (tillage, planting, harvesting, etc.) were required as well. Since the model would be run in NRCS field offices, ease of use and minimal runtime requirements were also issues that had to be adequately addressed. These non-wind erosion science issues had to be addressed prior to NRCS officially implementing and using WEPS. Some were not insignificant issues to resolve and several rounds of testing and evaluation with NRCS were conducted nationwide over a four year period since the release of WEPS to NRCS for review. All the critical issues identified by NRCS during that time frame are discussed here with an overview of the actual selected and implemented solutions presented.