Spatial and temporal variations in soil erosion sensitivity in Danjiangkou City

Soil erosion is a major ecological problem in Danjiangkou reservoir area. Therefore, understanding the soil erosion mechanism of Danjiangkou reservoir area and conserving the water environment of the reservoir area is critical. Based on the revised universal soil loss equation(RUSLE) and the terrain characteristics of mountainous and broken terrain in Danjiangkou City, five factors, including rainfall erosivity, soil erodibility, topographic relief, vegetation coverage, and gully density were selected to develop a soil erosion sensitivity evaluation system. With the help of ArcGIS 10.2 platform, the soil erosion sensitivity of Danjiangkou City from 2012 to 2017 was comprehensively evaluated and the spatial distribution characteristics of soil erosion sensitivity in the study area under different underlying surface elements were analyzed. The results showed that the soil erosion sensitivity of Danjiangkou City was generally high in the northern and southern regions and low in the central region. Soil erosion sensitivity was characterized majorly as marginal and moderate sensitivity. Highly sensitive and extremely sensitive areas accounted for 13.53% of the total study area; during the five years, the moderately sensitive, marginally sensitive, and insensitive areas in Danjiangkou City showed an increasing trend, while the highly sensitive and extremely sensitive areas showed a downward trend; sparse woodland and unused land were highly sensitive land use types in the study area. The potential risk index of soil erosion in the study area increased initially and decreased later with the increase in slope. The research findings can serve as a reference for studying the soil erosion mechanism and developing strategies for the conservation of soil, water, and the overall ecosystem in Danjiangkou City.