Study on topographic characters of soil erosion spatial distributionin in watershed on Loess Plateau

The study on the coupling relationship between the variation of soil erosion and geomorphological factors in watershed scale will contribute to the effectiveness of soil and water conservation. Based on soil erosion database, the topographic variations of soil erosion in watershed and the relationship between it with different geomorphologic factors were analyzed in the paper, with a case study of Wenanyi watershed located on Loess Plateau, through comprehensive application of GIS-based spatial analysis and digital terrain analysis methods. The results indicated that the main erosion type of Wenanyi watershed is splash erosion. The elevation characteristics of spatial distribution of water erosion with various intensities exhibits peak phenomenon. The distribution above light erosion was concentrated on the region with the altitude about 967-1067m. The critical slope of erosion in Wenanyi watershed is less than 22°. And Influences of slope gradient on soil erosion was not a single direct proportional correlation; The aspect characteristics of erosion in Wenanyi watershed showed double-peak structure, the area proportion of above intensive erosion was relatively high on north slope, while that on south slope was relatively low. There was a critical relief amplitude of erosion at about 40m. The changes of relief had less effects on the changes of soil erosion intensity. The results in the paper could provide scientific support and guidance for soil and water conservation and eco-environment management in watershed on Loess Plateau.