토사유출량의 공간분포 산정결과 평가를 위한 RUSLE와 LISEM의 비교

Abstract

Various models have been developed for the estimation of spatial distribution of sediment yield. However, they often generate distinct results because of differences in their development purposes and calculation processes. Therefore, it is challenging to verify the simulation result without ground measurements of spatially varying sediment fluxes. Here, we postulate that applying multiple models to a same watershed and checking whether they provide similar spatial distributions can be an indirect method of evaluating the performance of the models. To test this idea, we apply two models of LISEM and GIS-based RUSLE for a small watershed in Gyeonggi-do, South Korea, where actual sediment yield was measured at the outlet. Two models result in similar spatial patterns in the distribution of sediments yield. LISEM results show more evenly distributed sediment yield. This difference is partly due to the difference in model structures and due to the ranges of parameters chosen between the two models. Compared to RUSLE, there are limited references for model parameter values of LISEM in Korean practices. Helped by physically-based model structure, LISEM is expected to simulate sediment yield in a more reasonable manner, compared to RUSLE, once the appropriate ranges of model parameters are suggested in the future.