Calibration and Validation of the SWAT Hydrological Model for the Air Dingin Watershed

Computer technology has revolutionized the study of hydrological systems and management of water resources. Several computer-based hydrological models have been developed for applications in hydrological modeling and water resource studies. Geographic Information Systems (GIS) Interface models help create input data files, analyze and display results in a more efficient way. One interface GIS model available for water resources analysis is the Arc - Soil and Water Assessment Tool (ArcSWAT), a distributed parameter model developed by the United States Department of Agriculture. ArcSWAT has been applied, validated and calibrated for analyzing surface runoff in Air Dingin Watershed in Padang City West Sumatra Indonesia. Validation was conducted to test the accuracy of the model in representing the real situation of the Air Dingin Watershed. Furthermore, calibration was performed to enhance the accuracy of the model. The results of ArcSWAT validation indicated that the Nash-Sutcliffe Efficiency (NSE) value was 0.12 and Coefficient of Determination (R-2) was 0.4. After the calibration was carried out by changing the value of some parameters in the model, the NSE value becomes 0.68 and R-2 becomes 0.66. This accepted model furthermore could be used to simulate water balance in the Air Dingin watershed.