Sensitivity Analysis of SWAT Model in a Tropical Watershed, East Java

Abstract

Brantas watershed has approximately 14,103 km2 and play an essential role in supplying water for about 30% of the East Java population. Management of water resources in this watershed has become a challenging issue. Conformity of modeling processes and result to mimic the existing hydrological processes is still in question. This study aims to analyze the sensitive parameters of the Soil Water Assessment Tool (SWAT) model on the watershed. Hydrological processes are observed both monthly and annually. Sensitivity analysis using the SWAT-CUP tool show 18 sensitive parameters. 9 parameters have more than a 50% sensitivity level. 4 are correlated to the soil layer’s runoff generation and water movement. Then, 8 parameters correlated to baseflow calculation. Simulation results illustrate the strong effect of climate change (especially rainfall) on water yield and sedimentation.