Quantitative estimation of soil erosion in Shanxi Reservoir basin based on RUSLE

Soil erosion is one of the major problems facing the world today,and soil erosion in reservoirs is a serious problem reducing water storage volume and water quality. This paper took Shanxi Reservoir basin as the study area to evaluate the effects of the soil erosion on the reservoir water holding capacity and water quality. The Revised Universal Soil Loss Equation( RUSLE)model and GIS and RS technologies were used in the study. Through the Arc GIS spatial overlay analysis,we quantitatively analyzed the relationship between land-use types,slope,and soil erosion. The results showed that soil erosion in Shanxi Reservoir basin was moderate with an average erosion modulus at 3085. 76 t·km-2·a-1. In terms of erosion intensity,mild erosion occupied49. 42% of the area while the extremely severe and severe erosion occupied 10. 93% of the area.In terms of erosion quantity,only 0. 8% of total soil erosion amount came from the mild erosion area and 62. 15% from the extremely severe and severe erosion areas. Also 70. 21% of watershed area was covered by the forest,which became the main source of soil erosion accounting for70. 92% of total soil erosion amount. The study area was divided into seven slope belts. Soil erosion was most serious at the [15°,25°) and [25°,35°) slope belts,which occupied 55. 12%of the study area and 61. 35% of total soil erosion,respectively. A significant correlation between the soil erosion and the landslide events was found. The greater the intensity of soil erosion,the more likely the landslide happened. Therefore,strengthening soil and water conservation efforts in the severe erosion area could effectively improve the situation of soil erosion in the whole area.