Regional Scale Application of USLE and WEPP for Soil Erosion Assessment in Korea

Abstract

Due to the geographical location of Korea in the Asian monsoon belt, more than half of annual precipitation occurs during the summer season (May to September). This causes significant amounts of soil loss from croplands, which is directly linked to the deterioration of surface water quality. Therefore, accurate and real-time estimation of soil erosion has been a great concern in Korea. The purpose of this study is to implement two soil erosion models, the empirical Universal Soil Loss Equation (USLE) and the physical-based model of the Water Erosion Prediction Project (WEPP). Both USLE and WEPP are spatial-distributed regional-scale models. Model input files containing climate, soil, slope and cropping management are modified to consider Korean conditions. Necessary weather data are obtained from the Meteorological Information Web Service System-Disaster Prevention (MISS-DP) of Meteorological Administration in Korea. The Agricultural Soil Information System (ASIS) and Crop Information Center of Rural Development Administration provide soil, slope, and cropping management information for both models. Two cities with different topographic characteristics, Chun-Cheon (forest) and Jeon-Ju (level-plain) in Korea are used to assess the model performance in this study. The results of this study were that better erosion prediction using the WEPP model since it illustrates a higher degree of spatial variability than USLE in topography, precipitation, soils, and crop management practices. There was a little variability between the estimates in Chun-Cheon(r2=0.6841) and Jeon-Ju(r2=0.8891). In addition, the findings of this study were aided in developing the environmental assessment program to conserve the agricultural environment in Korea.