Quantitative assessment of regional soil erosion in chengdu plain of sichuan province

Soil erosion is a major environmental problem worldwide, threatening the human sustainable development. Global water erosion and wind erosion affect 1094 and 549 Mha, respectively. Soil erosion concerns multi factors, for example, land cover, climate, vegetation cover, topographic factors. Soil erosion is also different in different spatial and temporal scales. To monitor and assess the extent of soil erosion, multi data concerning these influencing elements need to be considered by combined use. Among these factors that influent the process of soil erosion, vegetation cover and slope steepness are selected. The vegetation cover data in the Chengdu plain have been estimated from normalized difference vegetation index derived from Landsat-7 ETM+ image acquired at 2000-11-02. Slope steepness is computed based on the pixels of DEM (Digital Elevation Model), the pixels of DEM are transformed from the 1:100000 terrain map. Vegetation cover and topographic factor can be combined as a cross tab model. A soil erosion risk map with six grades can be drawn. Using the method the probability and the extent of soil erosion can be measured. Remote sensing data provide a significant information source for mapping, monitoring and predicting current rapid soil erosion. In the analysis process of soil erosion monitoring geography information system takes very important roll. It can fuse different thematic data and different formats of data. This paper gives a brief synthesis of the information obtainable from remote-sensing data and DEM data, and assesses the status of soil erosion in Chengdu plain.