Research On Soil Erosion Based On 3S And The USLE Model

Soil erosion as a non-point source pollution, the loss of soil contained nutrients enter into water reservoir will increase the risk of eutrophication, it aroused widespread concern. In recent decades, with the 3S technology (remote sensing, geographic information systems and global positioning system) and the rapid development of soil erosion mechanism of the deepening, the 3S technology and the combination of soil erosion assessment model more and more attention.Danjiangkou reservoir located at Hubei, Henan and Shanxi province intersection points. It is the middle Route Project (MRP) for South-to-North Water Transfer of water resources, ecological environment around the reservoir area of the state of the Danjiangkou Reservoir direct impact on water quality. Under the national science and technology support key project's support, this article uses the 3S technology and US general soil erosion equation (USLE), has conducted the evaluation study to the Danjiangkou reservoir Henan domestic soil erosion condition and discussed the soil erosion to the Danjiangkou reservoir influence. The main conclusion is as follows:First, the study of regional remote sensing image is preprocessed to achieve before the general application of remote sensing image processing, and establishing the scope of the geographical environment of the basin interpretation signs of human-machine interactive visual interpretation methods used to obtain land use maps; normalized Extraction of the area of vegetation index of vegetation coverage.Take US general soil erosion equation USLE as the tool, to its r ainfall erosivity factor, soil erodibility factor, the plant cover factor, the topographical factor, the conservation of water and soil measure factor carry on the thorough analysis and the quantification research, realized has studied the region soil erosion quantity as well as the loss of soil nutrient quantity estimate. From 1991 to 2007, the research area's soil erosion quantity assumed the declining trend, the soil erosion modulus from 44.8 t·hm-2·a-1 to 16.9t·hm-2·a-1. In studies area the soil erosion caused by large amount of soil nutrient loss, loss of organic matter each year about 108,000 tons; an average annual loss of organic matter, nitrogen and total phosphorus is respectively about 108,000 tons,6,600 tons and 5,000 tons. Annual average nutrient loss modulus to organic matter 15.02 t/km2, nitrogen 0.92 t/km2 and total phosphorus 0.72 t/km2.To improve the reservoir's ecological environment, reduce non-point source pollution and ensure clean water in Danjiangkou much still remains to be done.