Quantitative Study Of Temporal And Spatial Variation Of Soil Erosion In Chakou Small Watershed Based On GIS And RUSLE Model

In the process of soil erosion research, RUSLE is the most widely used model currently to quantitatively estimate soil erosion. With the support of the RUSLE model, taking Chakou small watershed in Yonghe County, Shanxi province as the research object, based on the analysis of field investigation and observation data, a soil erosion quantitative calculation model was established by ArcGIS, to create a distribution map of soil erosion in Chakou small watershed and analyse the spatial distribution characteristics of soil erosion. Quantitatively calculated the value of each season and created distribution maps of soil erosion of each season in Chakou small watershed and comparatively analysed the seasonal variation of soil erosion in small watershed. The results showed that:(1) The area of slight erosion accounted for98.52%of the total area of the watershed; the highest erosion modulus was4377.82t·km-2·a-1, which doesn’t reach the highest erosion classification. The comparatively serious eroded area was mainly located in barren hillsides with slope greater than8degrees and villages with poor vegetation cover.(2) During calculating the value of each factor of the RUSLE model, the seasonal variations of the rainfall erosivity factor and vegetation coverage factor of different land use types were significant. From the point of the average soil erosion of each season, erosion in summer was most serious, with the average erosion modulus was94.2542t·km2·a-1, and erosion in winter was minimun; from the point of the highest soil erosion of each season, the highest erosion modulus of summer season was3530.0632t·km-2·a-1,which has reached moderate intensity erosion. The highest soil erosion modulus of autumn was smaller than that of summer, and the modulus of winter was180.7406t·km·a-1, belonging to slight erosion.By quantitatively calculating soil erosion modulus and classifying soil erosion of different land use types and different seasons, this paper provided reference for soil and water conservation planning in the small watershed.