GIS-based investigation of the impact of vegetation change on soil erosion in small watershed

This paper presents results of research works conducted in the Chujiazangzi watershed in Naimanqi County of Inner Mongolia within the Dalinghe River basin, which is the key area of the national program for soil and water conservation. The database of the watershed was developed with GIS technology. Based on observed data from the Soil and Water Conservation Experimental Station of Naiman, slope erosion model was established. The model can simulate soil erosion of the different topographic features and the vegetation cover. Change in soil erosion was calculated for conditions before and after the treatment. The impact of vegetation change in the watershed on soil erosion was analyzed. It was found out that if the forest area reaches 40% of the watershed, better protection will be provided. Vegetation under forest, litter layer and close protected grass are also effective for erosion control, where the amount of soil losses will be far less than the allowed amount soil erosion. The in-depth coupling between the soil erosion and GIS is realized, which could make the models' use of external data more efficient. In addition, the special- temporal distribution of soil erosion in the watershed was reflected in the model. The study also showed the importance of integrated watershed management.