SWAT Application for Gajahwong River Streamflow Simulation

Abstract

Gadjahwong River flows along Daerah Istimewa Yogyakarta (DIY) that is located in southern Java Island. Gadjahwong River has an important role for water supply purpose especially for agriculture activities. On the other hand, DIY is seeing 1.18% population growth each year. The population surge influences land cover change that can seize continuous discharge of Gadjahwong River. Therefore, continuous discharge simulation needs to be conducted for assessing Gadjahwong River water availability. Soil and Water Assessment Tool (SWAT) was employed for modelling Gadjahwong River streamflow discharge. The simulation result discharge was compared with observed data acquired at AWLR Wonokromo by using NSE and R2 statistical parameter. Finally, the statistical parameter was applied to justify quality of simulation. Findings showed that daily time step yielded NSE value of 0.61, R2 value of 0.79, and PBIAS value of -2.41%. Overall, the simulation showed good result based the statistical parameters.