Mapping and Simulating Watershed Performances Based on GIS, Remote Sensing, and SWAT

This study has demonstrated that the combination of the geographic information systems (GIS), remote sensing (RS), and the Soil and Water Assessment Tool (SWAT) has yield a comprehensive land use mapping and an assessment report of watershed performances. The Tapung watershed located in sub-watershed of Siak, Riau Province, Indonesia was appointed as a study area. This research identified that the existing land use condition (in 2012) was dominated by oil palm plantation (46%), agriculture (24%), and bushes including shrubs (8%), and a small number of forest area (7%). Thus, there was a need for conducting reforestation management programs within the watershed areas in order to maintain the watershed performances. However, based on this study the existing watershed performances (scenario 1) was in the state of moderate conditions as the percentage of the critical coverage areas (PLK) was small (10.41%), with the annual water flow coefficient or water run-off (KRA) was high (0.45). Hence, there was a need to reduce this run-off to become 0.40 and NS = 0.50 > 0.36. Hence, this study confirmed that the GIS, RS, and SWAT were capable for mapping and simulating the watershed performances systematically.