Using Rs And Gis To Value The Water Conservation Function Of Forest Of Reservoir Basin

Landsat /TM image data was used as data source in the study, and the image data was processed with the support of the methods- geometric correction, spatial enhancement and the unsupervised classification, as a result a unsupervised classification image was output. And using global positioning system (GPS), with some geographic information data, we have had filed survey to demarcate the classification image. Then with the assistance of Arc/Info geographic information system (GIS) and Arcviwe 015, a vectorgraph was made, by which Xigou reservoir basin was classified into 11 kinds of land use types, and a classified map of land use was output, at the same time areas of all land use types were calculated automatically.After a lot of field survey and study in laboratory, with the assistance of the classified map of land use, we studied and valued water retention ability of soil of the Xigou reservoir basin, at the same time a classified map of water retention ability was made. As a result the water retention ability of soil of the basin was classified into five ranks.According to the study above and the hydrographical data throughout 2000, the water conservation of forest types in the four main water collection area (Kunaer river, Honghutu river, Gongbiela river and Halatai river) were systematically analyzed and evaluated. The study shows that the water retention ability of forest in the studied area, at present, is different among the different forest types, and enhanches with the forest coverage increasing.The suggestions relevant to the establishment of management system in the area were put forward in this paper.