Application And Comparison Of GeoWEPP Model And USLE Model To Natural Small Catchment - A Case Study In Anseong-si, South Korea

The empirical USLE and the physically-based GeoWEPP which were distributed model linked with GIS (Geographical Information System) were applied to small natural catchment located in Anseong-si, Gyeonggi- do, South Korea. The results using by two models were total soil erosion and total sediment yield from study catchment from June, 2005 to May, 2006. During the study period, the total soil erosion computed by USLE and GeoWEPP model was 95.1 ton and 112 ton, respectively. The observed total sediment yield that was deposited in the reservoir was about 32 ton. The computed by USLE and SDR(Sediment Delivery Ratio) curve suggested by NCHRP was about 19 ton and computed by GeoWEPP model was 30.1 ton, respectively, during the study period. Each of total sediment yield computed by USLE and GeoWEPP underestimated more than the observed total sediment yield, but, based on the results, the total sediment yield computed by GeoWEPP approximated to the observed result. However, two models had a problem that the process and spatial trend of soil loss using by the models were different from those of the actual condition in-situ. We suggest that the prudent caution needs to apply the models to real world and the many applications to various area needs to obtain more proper results. Key Words : Soil erosion, Sediment yield, GeoWEPP model, USLE model