Investigating SWAT model efficiency to determine water balance components (case study: Sungai Muda Watershed)

Abstract

Sungai Muda watershed is one of the most important watersheds which serve as a source of water supply for the agriculture, domestic sector, fishery, and hydropower. In this study, water balance components were simulated using the SWAT hydrological model to investigate the model efficiency and its ability to use as a water balance simulator in the Sungai Muda Watershed. The SWAT model was calibrated for ten years (1981–1990) with a value of the coefficient of determination, R2 = 0.76. Then, the model was validated for ten years (1997–2006) which gives R2 = 0.71. Finally, the calibrated SWAT model was used to simulate the water balance components of the Sungai Muda watershed. The results showed that 42% of precipitation enters the atmosphere through evapotranspiration, and approximately 30% of it goes to the waterway as the surface runoff and lateral flow, while 28% of water enters the soil layers as the underground water. The results of this research showed the acceptable performance of the SWAT model to simulate the water balance in the Sungai Muda watershed, and the model can be used for water resources planning in this study area.