福州市饮用水源保护区水土流失风险评价

Soil risk assessment of the drinking water source conservation district in Fuzhou city

选择植被覆盖度、地形坡度和土地利用类型来进行水土流失的风险度评价;试验区域为福州市第二饮用水源地山仔库区和塘坂库区;利用Landsat-7ETM+的影像,在计算归一化差分植被指数NDVI的基础上估算水源地保护区的植被覆盖度;利用栅格数字高程模型DEM,计算地表坡度;利用土地利用类型图获取保护区各地土地利用类型的分布;根据水利部部颁标准,对植被覆盖度、坡度和土地利用类型进行分级,建立水土流失风险评价模型,并在ArcGIS9.0软件支持下,对上述各因子进行叠加分析,得到保护区水土流失评价风险评价;结果表明研究区内生态环境总体保护较好,但存在一定的水土流失现象,生态环境保护还需进一步加强。

The process of soil erosion is complex. Among many factors that influence the process of water and soil erosion, vegetation cover, slope steepness and land-use are selected. The vegetation cover data in Sanzai snd Tangban have been estimated by normalized difference vegetation index derived from Landsat-7 ETM＋ images. Based on the pixel of DEM slope steepness is computed. The spatial distribution of land-use is based on the map. A soil erosion risk map with six grades can be drawn. Using the method the probability and the extent of soil loss can be measured. This study describes and assesses soil erosion.