Monday, November 5, 2007 - 3:20 PM
110-8
Effects of Management Practices on Nutrients and Sediment in Runoff Determined with SWAT for Wahoo Creek Watershed of Southeastern Nebraska.
Ahmed Alwadaey1, Charles Wortmann, Thomas Franti2, Charles Shapiro3, and Dean Eisenhauer4. (1) Agronomy and Horticulture, University of Nebraska-Lincoln, 279 Plant Science, Lincoln, NE 68583-0915, (2) Biosystems Engineering, University of Nebraska-Lincoln, 231 Chase Hall, Lincoln, NE 68583-0726, (3) 57905 866 Rd., University of Nebraska-Lincoln, University of Nebraska-Lincoln, Haskell Agricultural Laboratory, Concord, NE 68728-2828, (4) PO Box 830726, University of Nebraska-Lincoln, University of Nebraska-Lincon, Biosystems Engineering, 238 LW Chase Hall, Lincoln, NE 68583-0726
Nutrients and sediment loss from watersheds contributes to water quality pollution. A study was conducted to determine the impact of agriculture practices on nutrients and suspended sediment loss from Wahoo Creek watershed. Runoff and loading of sediment and nutrients were assessed using SWAT simulation. The Wahoo Creek watershed area is approximately 93,000 ha. Land use is 34 % corn, 32% soybean, 24% pasture. The rest of area consists of alfalfa, trees, other crops, and low urban density. Aksarben and Judson are the dominant soil series. Eight years (1996-2003) of weather data, Ssurgo soil data, and land use data were used for model simulation. SWAT divided the watershed into 28 sub-basins to investigate the most susceptible areas in the watershed based on the flow at the watershed outlet, phosphorus, nitrogen, and sediments concentration. The result of the analysis indicated that hydrologic response unit within sub-basins had effect on the stream flow and nutrients outputs. The upland areas, in corn and soybean production, and with diverse soil series including Sharpsburg , Aksarben, Morril, Steinauer, and Judson were susceptible subbasins to nutrients and sediment loss. Implementing of agriculture practice such as terraces, ponds ‘dams’ decreased stream flow, nutrients and sediment loss at the watershed outlet by ...% Compare with Non-agriculture practice scenarios. Three scenarios are grass filter strip, land cover or residue and tillage practices were performed during model simulation to evaluate their impact on sediment and nutrient loss.