|Fox, Jr, Fred|
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 8/11/2020
Publication Date: 9/3/2020
Citation: Hagen, L.J. and F.A. Fox. 2020. Erosion submodel of WEPS. In: Tatarko, J., editor. The Wind Erosion Prediction System (WEPS): Technical Documentation. USDA Agriculture Handbook 727. United States Department of Agriculture, Agricultural Research Service, Beltsville, MD. p. 85-157.
Technical Abstract: The erosion submodel of the Wind Erosion Prediction System (WEPS) calculates the wind energy available at the soil surface to cause erosion and the erosion processes in prediction equations for the saltation/creep and suspension components. Given the wind velocity above the surface, the friction velocity at the soil surface is found accounting for the effects of wind barriers and surface roughness and cover. The erosion processes begin with calculation of surface threshold friction velocities and end with periodic updates in surface conditions caused by the soil loss and deposition that occur during erosion. Wind erosion equations for a uniform surface during quasi-steady conditions are based on the principle of conservation of mass. The major processes involved in saltation/creep creation and transport are simulated. These processes include direct emission of loose material, entrainment of material abraded from exposed clods and crust, breakage of saltation/creep aggregates into suspension-size, trapping of saltation/creep when transport capacity is exceeded on micro-relief, and interception by plant stalks. In a second portion of the submodel, the major processes involved in creation and transport of the suspension component of wind erosion are simulated. These processes include emission of loose material, abrasion from exposed clods and crusts, and breakage of the saltation/creep to form suspension-size aggregates. A downward flux to the surface of coarse fractions of the suspension component is also simulated in portions of the simulation region, where saltating aggregates were not present. The erosion submodel of WEPS provides estimates of onsite and offsite impacts of erosion and also predicts the size components of the moving soil for improved conservation planning and evaluations of associated environmental impacts.