基于GIS的小流域土壤侵蚀评价研究

以珠江上游九溪河小流域为研究区域 ,采用美国通用土壤流失方程 (USLE模型 )为评价模型 ,以地理信息系统软件ARCVIEW 3 .2为分析平台 ,并在ARC/INFO 7.1 1及VisualFoxpro 6.0支持下 ,进行小流域土壤侵蚀评价。通过建立数字高程模型、TIN模型 ,数字化土地利用类型、植被类型、土壤类型等矢量图层 ,空间数据与属性数据连接 ,矢量、栅格数据转换 ,地图代数运算等操作步骤 ,获取基于栅格数据的小流域土壤侵蚀量。经分析 ,在不同的土地类型中 ,裸岩区及荒地的土壤侵蚀量最大 ,是有林地的 8倍以上。在各种植被类型中 ,经济林的土壤侵蚀量最大 ,而其它植被类型的差异不显著。影响小流域土壤侵蚀量最显著的因素是坡度因子 ,2 5°以上的坡度土壤侵蚀量是平地的 54倍以上。最后 ,找出了小流域水土流失治理的关键因子是坡度和植被 ,并提出相应治理措施

Evaluation of Soil Erosion Based on GIS in a Small Watershed

Based on the platform of Arcview 3.2,ARC/INFO 7.11 and Visual Foxpro 6.0,Soil erosion in the watershed of Jiuxihe in the up reach of Pearl River was evaluated by using universal soil loss equation(USLE).The factors related to soil erosion were inputted to Arcview in vector,which included topography,landuse,vegetation type,soil type,and converted to grid.Then cell based soil loss was calculated by using USLE based on map algebra.The result showed that:(1)In different landuse types,soil loss on wasteland was eight times that on the woodland.(2)Soil loss in economic forest was the biggest in different vegetation types.(3)Slope was the most important factor related to soil erosion,and soil loss on the land where slope was over 25,was fifty four times that on the flat.Afterward,the key factors and solution dealing with soil erosion harness were found out,which were slope and woodland.