Sediment Yield Estimation for Watershed Prioritization: a Remote Sensing Study

Watershed prioritization on the basis of soil erosion has become inevitable component of watershed management in order to conserve this precious natural resource. The major factors contributing to the soil erosion include the land use, the soil, the slope, the climate and the land management practices. These factors exhibit spatial variability due to watershed heterogeneity. Therefore, the watershed is usually discretized into sub-areas exhibiting some sorts of homogeneity. In this study the watershed is subdivided into a number of micro-watersheds and the emerging technology of remote sensing as data source was used for obtaining reliable and real time information on land use and soil. The information on slope was obtained from topographic maps. The land-use, the soil and the slope are used in a simple mathematical model for estimating sediment yield of each micro-watershed and thereafter the micro-watersheds were statistically classified into four priority classes. The advantages of using satellite images are discussed. It is recommended to use images with resolution of 2-5 m (e.g., SPOT 5) as a cost-effective data source for sediment yield estimation and other watershed management activities.