Fuyingzi Small Watershed Soil Erosion Evaluation Research Based On The USLE Model

Fuyingzi Small Watershed is located in Chengde, Hebei province. It lies in north eastern of Yanshan with a basin area of 35.89 km2 and belongs to low hilly area. The paper referred to academic research of soil erosion both at home and abroad and used Fuyingzi Small Watershed as the research object. And it analyzed the remote sensing images, rainfall and land data with the help of geographic information system analysis software. After that, it selected rainfall erosion force, soil erosion force, long slope gradient and vegetation coverage formula suitable for local conditions and made quantitative analysis on the soil erosion influence of each factor by soil-loss-equation USLE model.Studies had shown that the erosion intensity of land use unit in Fuyingzi Small Watershed differed significantly. The soil erosion modulus was between 24.12t/km2·a～8916.33 t/km2·a, and the average number was 2149.26 t/km2·a. The annual sediment yield in 2013 was 77136.94t. The moderate soil erosion area,15.73 km2, was the biggest area according to the study results, which accounts for 43.83 per cent of total basin area. While the strong soil erosion area was 0.02 km2, the smallest area, which accounts for only 0.01 percent. Different vegetation coverage was relatively close related to soil erosion intensity strength in the river basin. The soil erosion intensity reduced while the vegetation coverage increased except bare land. In addition, the erosion intensity increased along with the positive change of slope and elevation. Extremely strong erosion existed in the area with the height of over 2000 meters, the vegetation coverage between 15% and 45% and the slope of over 35 degree. Strong erosion existed in the area of the vegetation coverage between 15% and 65% and the slope between 15 and 35 degree. Those areas should be mainly monitoring, and preventing from water loss and soil erosion.Based on the principles of ecological protection and comprehensive curb, the study divided the small watershed into three categories named the comprehensive ecological restoration area, the general curb area, the ditch river and circumjacent curb area according to the Fuyingzi local land usage and natural economy status. Facing with different districts’ situations, the paper simulated corresponding control measures of soil and water conservation, providing a theoretical basis of ecological construction for similar areas and a scientific basis for the local government to carry out soil and water conservation work.