GIS-FMADM for Land use Management at Mamasa River Basin South Sulawesi Indonesia

In the recent years, the function of Mamasa River Basin can not be performed optimally in maintaining sustainability hydrologic function of Garugu dam. It is indicated by the occurrence of floods in rainy season and in contrary water shortage in dry season. Unexpected hydrology functions can be attributed to inappropriate land use at the upstream. Therefore, in order to maintain the hydrologic function of the dam, it is necessary to formulate suitable land use at upstream of the river basin. This research is objected to formulate the suitable land use, in term of reducing sedimentation rate in Garugu dam. This study employed RUSLE (Revised Universal Soil Loss Equation) for calculating erosion as well as sedimentation rate. Fuzzy Multi Attribute Decision Making (FMADM) and Analytic Hierarchy Process (AHP) which are integrated with Geographical Information System (GIS), that ware used to formulate optimum landuse at the upstream. Focus Group Discussion (FGD) was conducted in order to validate the obtained land use model using FMADM formulation. The optimum land use composition for Mamasa River Basin that control of dead storage of sediment (DSS) is: 38.01% of agroforesty, 17.88% of forest, 15.66% of mixed agriculture, 11.30% of mixed garden and forest fruit crops, and the rest of the conservation actions and land use such as strip cropping, rotation of crops, use bench terrace in rice fields, reforestation, cover crops and coffee plantation. The optimal land use composition can control the sedimentation rate up to 127.22 m3/km2/year