Potential Hazard Degree Evaluation Of Representative Water Erosion Region In China Based On GIS

The study and practice on soil and water have manifested that it can't reflect the serious and hazard of soil and water erosion in its entirety only depend on soil and water erosion intension. At the same time, it can't make a good evaluation of tendency in future. Developing study on countrywide hazard degree of soil and water erosion can provide basic data for analyzing and evaluating the degree and tendency of region soil and water erosion objectively, science basis for national Eco-construction of soil and water conservation decision-making. This study is developed under the background of integrated science review of Chinese soil and water erosion and ecological safe, which was developed by Ministry of Water Resources, Chinese Academy of Sciences and Chinese Academy of Engineering. As a sub-topic of the subject group who study soil and water erosion and basic data integration, its result will provide basic data for evaluating the status of countrywide soil and water erosion directly.According to the subarea of soil erosion type in our country, water erosion region is caved up into seven type regions, which contains Black Soil Region in Northeastern China, Soil Stone Mountain Region in Northern China, Loess Plateau Region in Northwestern China, Upper Reaches of Yangtze River and Reaches of Southwest River Region, Red Soil Region in Southern China, Rocky desertification Region in Southwestern China, Wind-Water Interaction Region in Northern China, and so on. In each type region, soil and water erosion type is divided secondly into 30 typical regions. We select typical land sections in each typical region, analyze the hazard degree of soil and water erosion, and reflect the hazard degree status of countrywide soil and water erosion. In each typical land section of typical regions, we select a breadth of relief map in scale of 1 to 10000 as a survey cell, get data of land use, vegetation cover, effective thickness of soil layer through field survey, get terrain grade information through vectoring the relief maps, then complied the water erosion classification standard of water resources technical standard《soil erosion classification》(SL 196-96), overlay the layers of land use, vegetation cover, terrain grade and other soil and water erosion factors with GIS software, analyze and evaluate the intension and hazard degree of soil and water erosion of each survey cell and typical region.Through the analysis of water erosion intension and hazard degree of the five regions and 20 typical regions, we can reach conclusions as following:(1)The area of land which exists soil and water erosion hazard in each typical region is large. In a...