| Popis: |
The Conservation Effects Assessment Project (CEAP) of the United States Department of Agriculture (USDA) is targeted at determining the impacts of conservation practices on off-site losses of sediment, nutrients, and pesticides. One of the Agricultural Research Service (ARS) benchmark CEAP watersheds is the St. Joseph River Watershed, located in northeastern Indiana, northwestern Ohio, and southern Michigan. The USDA-ARS National Soil Erosion Research Laboratory (NSERL) in West Lafayette, Indiana, has been conducting field and watershed monitoring in sub-basins of the St. Joseph River watershed since 2002. The area is largely agricultural, with major crops of corn and soybeans. Soils are moderately to poorly drained, and the topography is flat to gently rolling, with large numbers of closed surface depressional areas (potholes). While a number of hydrology and pesticide simulations have been conducted for this location with larger scale watershed models, no detailed modeling of sediment loss has been done up to this point. This paper will describe application of the Water Erosion Prediction Project (WEPP) model to small fields (~2 ha) where detailed measurements of climate, soil properties, topography, management, and storm runoff and sediment loss are available. Adequacy of WEPP model predictions will be evaluated, and model calibration and validation results presented. WEPP was also applied to the next larger scale of watersheds (~250 ha) to determine potential effects of land management practices there on runoff and sediment loss. Some typical alternative management practices evaluated were conservation tillage, buffer strips, and conversion of critically eroding regions to forest or grass. |
