Author
FERNANDEZ, C - WASHINGTON STATE UNIV. | |
WU, J - WASHINGTON STATE UNIV. | |
MCCOOL, DONALD | |
STOCKLE, C - WASHINGTON STATE UNIV. |
Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/10/2002 Publication Date: 5/1/2003 Citation: FERNANDEZ, C., WU, J.Q., MCCOOL, D.K., STOCKLE, C.O. ESTIMATING WATER EROSION AND SEDIMENT YIELD WITH GIS, RUSLE, AND SEDD. JOURNAL OF SOIL AND WATER CONSERVATION. 2003. Interpretive Summary: Water erosion is a serious and continuous environmental problem. Rill and interrill erosion, two common forms of water erosion, involve detachment and transport of soil particles from top soil layers, degrading soil quality and reducing the productivity of affected lands. In addition, excessive sedimentation clogs stream channels and increases costs for maintaining water conveyances. Sediment delivered into water bodies may also be a source of contamination, adversely impacting the aquatic biota. In order maximize benefits for funds and efforts expended, it is essential to quantify the effect of conservation activities on the amount of erosion and sediment delivery in a spatially distributed form at the watershed scale. A comprehensive methodology that integrates erosion models, Geographic Information System (GIS) techniques, and a sediment delivery concept for estimating water erosion and sediment delivery at the watershed scale was developed. The method was applied to a typical agricultural watershed, in the state of Idaho, which is subject to increasing soil erosion and flooding problems. Current cropping and management practices and selected, feasible, potential management practices were evaluated to determine their effects on average annual soil loss. Substantial reduction in water erosion can be achieved when conservation support practices are applied. The integrated modeling approach allows for relatively easy, fast, and cost-effective estimation of spatially distributed soil erosion and sediment delivery. It thus provides a useful and efficient tool for predicting long-term water erosion potential and assessing downstream impacts of various cropping systems and conservation support practices. Technical Abstract: A comprehensive methodology that integrates erosion models, Geographic Information System (GIS) techniques, and a sediment delivery concept for estimating water erosion and sediment delivery at the watershed scale was presented. The method was applied to a typical agricultural watershed, in the state of Idaho, which is subject to increasing soil erosion and flooding problems. The Revised Universal Soil Loss Equation (RUSLE) was used to assess mean annual water erosion. The Sediment Delivery Distributed (SEDD) model was adapted to determine sediment transport to perennial streams. The spatial pattern of annual soil erosion and sediment yield was obtained by integrating RUSLE, SEDD, and a raster GIS (ArcView). Required GIS data layers included precipitation, soil characteristics, elevation, and land use. Current cropping and management practices and selected, feasible, future management practices were evaluated to determine their effects on average annual soil loss. Substantial reduction in water erosion can be achieved when conservation support practices are applied. The integrated approach allows for relatively easy, fast, and cost-effective estimation of spatially distributed soil erosion and sediment delivery. It thus provides a useful and efficient tool for predicting long-term water erosion potential and assessing downstream impacts of various cropping systems and conservation support practices. |