Application of geographic information system (GIS-IDRISI) for assessing land use risks on sediment yields

The land use development on the catchment area have to consider the sustain ability of the natural resources, particularly water and soil fertility. Th erefore, the risks of land use development must be minimized. This paper pr esents a methodology and analysis of the land use risks on sediment yield f rom a catchment area and propose some suggestions to maintain the catchment area function. The universal soil loss equation (USLE) in combination with IDRISI software package was used in this study. Five thematic maps of USLE parameters; rainfall erosivity (R), soil erodibility factor (K), length-sl ope-steepness factor (LS), land use factor (C), and conservation factor (P) were constructed by digitizing them on computer data base with an element size of 200 X 200 m(2). The spatial and temporal changes on catchment area (land use and sediment yield) were obtained by comparing two set of maps fr om different period. The proposed method is applied at Wonogiri catchment a rea in Indonesia. From this study, it was found that there are significant risks of the land use on the sediment yields and the existing land use have to be modified to reduce the sediment yields.