Tuesday, November 6, 2007 - 9:55 AM
203-2

Irrigation-Induced Erosion, Concepts and Modeling Challenges.

Robert E. Sojka1, D.L. Bjorneberg2, T.S. Strelkoff2, M.A. Nearing2, T.J. Trout2, and T.L. Spofford3. (1) USDA-ARS, Northwest Irrigation & Soils Research Laboratory, 3793 N 3600 E, Kimberly, ID 83341, (2) USDA Agricultural Research Service, Northwest Irrigation and Soils Research Laboratory, 3793 North 3600 East, Kimberly, ID 83341, (3) USDA Natural Resources Conservation Service (Retired), 19390 Braeburn Dr., Soap Lake, WA 98851-9714

Irrigation- and rain-induced erosion result from similar physical and chemical processes, but very different systematics; thus, both cannot be predicted well using the same models.  Modeling requirements for prediction of surface irrigation-induced erosion differ most from rainfed models.  Poor predictive capability for surface irrigation erosion is especially problematic since surface irrigation accounts for 90% of world irrigation.  Globally, irrigation averages twice the yield and three times the profit of rainfed agriculture.  In the US 80% of fresh fruit and vegetable production is irrigated.  Irrigation also plays a vital role in atmospheric cooling and C sequestration.  The importance of developing a robust, reliable, accurate, transient state erosion model for all forms of irrigation can hardly be over-stated.  Regional and national assessments of erosion and water quality impairment from irrigation runoff have been hampered for decades by the lack of appropriate models.  This hinders management choices, resource conservation strategies and policy, as well as conservation practice compensation.  Our paper details the aspects unique to irrigation that must be accounted for in models, and summarizes the progress toward irrigation-induced erosion model development.