Ike Sari Astuti, Kamalakanta Sahoo, Adam Milewski, Deepak R. Mishra
Upper-Brantas watershed in East Java, Indonesia, is a tropical watershed experiencing rapid landscape change, a phenomenon typical to developing countries. This study demonstrates the impact of Land Use Land Cover (LULC) changes on surface runoff in a tropical, urbanized, and data scarce watershed. The LULC changes were quantified between 1995 and 2015 and their impact on the hydrological processes was analyzed using the Soil and Water Assessment Tool (SWAT) model. During the study period, the watershed experienced an increase in settlement and dryland agriculture, and a decrease in the forest, rice field, and sugarcane plantation. The SWAT model results for the calibration (2003–2008) and validation (2009–2013) periods matched observed values [R2 > 0.91 and NSE (Nash-Sutcliffe Efficiency) >0.91]. In the long-term, the model predicted changes in runoff (+8%), water yield (+0.28%), groundwater (−1.8%), and evapotranspiration (−1.15%) due to changes in LULC. LULC changes showed a linear relationship with runoff generation, and the most significant factors affecting surface runoff were changes in the forest, agriculture, and settlements. Increasing urbanization, industrialization, and agricultural intensification will increase runoff which in turn will enhance the flow of nutrients and sediments into the water bodies. © 2019, Springer Nature B.V.
Department of Geography, University of Georgia, Athens, 30602, GA, United States; Department of Geography, Universitas Negeri Malang, Jawa Timur, 65145, Indonesia; College of Engineering, University of Georgia, Athens, 30602, GA, United States; Forest Products Laboratory, United States Forest Service, Madison, 53726, WI, United States; Department of Geology, Water Resources & Remote Sensing Group (WRRS), University of Georgia, Athens, 30602, GA, United States
