Research And Application On Water Erosion Model Of Karst Area Based On GIS

Landforms caused by karst role, called karst, karst topography. There are wide areas of karst topography in China which are gravity with rocky desertification. Rocky desertification is the result of erosion, so there is an urgent need for preventing the local soil erosion, and suitable local soil erosion model needs to be built. Soil erosion model based on the technology of GIS and remote sensing has been widely used in the industry, but researches on soil erosion of the karst area are still exile. The purpose of this paper is to study the soil erosion model of karst area of Zhuzhi project in Guangxi. Based on RUSLE and researches before, evaluate the sensitivity of soil erosion, then choose the main impact factor and correct it. The soil hydraulic erosion model with watershed scale is built. The new model is used to calculate the amount of soil erosion, and then verify the results to ensure the model is right. It is meaningful because the research can not only provide a reference for soil erosion law study in karst area, but also offer a consultation for hydraulic erosion model application and promotion. There are several results of this paper:(1) Extracted the factors based on RUSLE, and then evaluated the soil erosion of karst area, so the extent where there the erosion may occurred and how the spatial distribution was could be ensured.(2) Explored the relationship between sensitive area and impact factor, with soil erosion sensitivity classification result as the understructure. The result shows that there is a canonical correlation between them, of which C factors played the most important role, with related coefficient of0.785.(3) Combined with the actual situation of the study area, the C factor which is the most important one to influence the erosion was repaired, then RUSLE was changed to a new pattern with a higher accuracy.(4) Comparing the results which was calculated with them tested in the study area in2010, the accuracy of the model calculations were verified, which is85.86%. It is showed that the model is suitable for application in the karst area.(5) Rusults calculated by repaired RUSLE show that:after the Zhuzhi project implemented the study area, the average annual amount of soil erosion reduced from589,300t to271,100t, a decline of53.99%. Soil erosion modulus reduced from1594.69t/(km2·a) to733.61t/(km2·a), with decreasing the most of severe erosion, followed by strong erosion. Area of moderate erosion increased, when area of light erosion had been reduced. The effect of the project is excellent.