基于GIS的东苕溪典型小流域土壤侵蚀风险评估

基于GIS信息平台,采用土壤流失评估模型（USLE）对东苕溪典型小流域的土壤侵蚀强度进行估算评价,识别了土壤流失关键源区。结果表明：东苕溪典型小流域土壤侵蚀量在时间上与降雨量有较好的相关性（r=0.730,P〈0.05）,侵蚀方式以水力侵蚀为主;年均土壤侵蚀模数为2347t·km-2,属轻度强度侵蚀,土壤侵蚀强度呈现南北两端高,中部地区低的趋势;不同土地利用类型土壤侵蚀强度差异显著,年均侵蚀模数城镇用地〉农村生活用地〉耕地〉林地〉园地;中度及强度侵蚀区主要发生在陡坡带及7°～12°的耕地,极强度及剧烈侵蚀区主要集中在坡度大于12°的耕地、城镇用地及农村用地。

Assessing Soil Erosion Potential Using GIS for A Typical Watershed in East-Tiaoxi Basin, China

Using a Geographic Information System（GIS）and the Universal Soil Loss Equation（USLE）, we assessed the soil erosion potentials for a typical watershed in East-Tiaoxi basin. The results showed that there existed positive correlation between soil erosion and rainfall intensity （r=0.730,P〈0.05）. Rainfall erosion was the main form of soil erosion in the watershed. The annual average soil erosion modulus amount- ed to 2 347 t·km-2, which fall into the category of mild-degree erosion. Besides the rainfall, the vegetation cover was important factor causing soil erosion. The erosion in the watershed was generally stronger in southern and northern part than that in the central. In terms of land use/ cover categories, the annual average soil erosion intensity was in sequence：urban〉rural〉cropland〉forest〉orchard. It was also indicated that human activities had great influence on soil erosion. In addition, slope was correlated with soil erosion modulus. The middle and high intensi- ty of erosion were found in steep slope zone and the cropland with the slope ranged from 7° to 12°. The intensive and extremely intensive ero- sion were found in the cropland, urban land and rural land with slope greater than 12°.