The investigation and evaluation of soil and water loss in the Zhangjiachong watershed

The investigation and evaluation on the soil and water loss of Zhangjiachong Watershed, which is the typical watershed in the Three Gorges Reservoir Area has a great scientific values for the water-soil conservation in the Zhangjiachong Watershed and other watersheds located in Three Gorges Reservoir Area. In this study, the soil and water loss in Zhangjiachong Watershed was investigated on the spot and evaluated quantificationally, the research results shows the following: (1) The area of soil and water loss takes up to 60% of total area of the Zhangjiachong Watershed, among which the area whose sheet erosion intensity reaches medium or greater is beyond 70% of the total area of soil and water loss; the total number of the soil in erosion is 6705t, the soil and water loss is serious. (2) The soil with puffed structure provides the substances for the soil and water loss; dissected topography and concentrated rainfall results in mechanical motivation for soil and water loss; the growing population and the increasing of engineering intensity motivate and intensify the magnitude of soil erosion greatly, and exacerbate the soil and water loss. (3) The local government has adopted terracing of the land on the slopes, water storage engineering on the sloping land, the eco-system such as Contour hedgerow and economic forest system and the improvement of the agriculture tech, which has prevented the soil and water loss obviously.