Hydrological Response to Land use and Land Cover Change in Katonga River Basin, Uganda

Abstract

River basins are vital water resources that provide sustainable fresh water for anthropogenic activities. Land use and land cover changes (LULC) in Katonga River basin have had a negative impact on the fresh water resources leading to the reduction on the quantity and flow characteristics of water. The objective of this study was to predict and model the impact of land use/cover change on streamflow in Katonga River basin using HBV model. The study examined land use change impacts on the hydrology and hence produce the potential results based on the historical changes and the future scenarios of the river basin. The use of HBV model coupled with ArcGIS for digital processing of data was applied to study the catchment characteristics and its response to hydrological changes by understanding the effect on the stream flow changes of the river. The modelling of the basin focused on hydro-meteorological for a period 1990-2018 using HBV and the Eto calculator from FAO. To evaluate the model performance calibration and validation was performed using periods (1991-1995) and (2006-2010) respectively. The Coefficient of Efficiency/ determination (R2), model efficiency/Nash-Sutcliffe Efficiency (NSE), Kling Gupta Efficiency (KGE) were parameters considered for calibration and validation criterion. The values obtained for the Model efficiency/NSE is 0.43, Criterion coefficient R2 0.57 and KGE 0.477 for the calibration period and 0.39, 0.41, and 0.54 respectively for the validation period. The model performance was rated satisfactory according to the NSE-criterion from the obtained calibration values for different simulations. It was concluded that streamflow trend of the basin was greatly affected by land use/ cover changes with more negative impacts evident. This study also explains the implications of extensive bad land use policies that affect catchments and therefore different strategies of ecological sound system management, watershed and development strategies are paramount for water resources management and governance.