Study on the Topographic Effect on Soil Erosion Using RUSLE Model for Small Size Watershed

摘要

Soil erosion and subsequent sedimentation have caused serious environmental and soil degradation problems in Okinawa Prefecture,Japan.This research aims at evaluating an availability of the Revised Universal Soil loss Equation（RUSLE） for predicting the range of soil loss values for the Nago watershed in Okinawa.It shows that climatic conditions substantially influence the rainfall amount as a function of the I30 of the rainfall event.The rate of soil loss is higher with increasing in altitude due to greater slope steepness.By rainfall data analysis,it is concluded that the large difference in soil loss between 2000 and 2001 was due to concentrated heavy rainfall in the rainy season or the typhoon season.