Assessment of Climate Change Impact on Surface Water Resource Availability of Sibilu River Catchment,Upper Abbay Basin, Ethiopia
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Date
2024-06
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Addis Ababa University
Abstract
Understanding the effects Climate change impact on Surface water resource availability is the key point for sustainable management of natural resource. These changes would happen through changes in rainfall patterns, temperatures, and stream flow. The Coordinated Regional Downscale Experiment (CORDEX) was applied. Two Representative Concentration Pathways (RCP4.5 and RCP8.5) scenario for two future periods of 2050 (2031-2060) and 2080 (2061-2090) was used for climate projection. The projected maximum and minimum temperature will increase under both RCP4.5 and RCP8.5 scenario for near-term and long-term future periods by 1.9 0C, 2.8 0C, 2.2 0C, and 4.1 0C, and 1.9 0C, 2.9 0C, 2.5 0C, and 4.5 0C respectively. The projected potential evapotranspiration will increase by 6.3% to 8.6% for RCP4.5 scenarios and 6.7% to 11.4% for RCP8.5 scenarios under future periods. The projected the rainfall projection during the rainy season decreased by -5.8% to -1.2% for RCP4.5 scenarios and -3.7% to -0.4% for RCP8.5 scenarios under future periods as a result of increased projected temperature and potential evapotranspiration. HBV-Light model was used to simulate stream flow from 1985-2002 periods for calibration and 2003-2011 for validation periods. The model performance showed with R2=0.91, NSE=0.88, and PBIAS=13.43% for calibration and with R2=0.85, NSE=0.77, and PBIAS=15.07% for validation. Future simulated stream flow of the Sibilu River showed a decreasing trend during the rainy season, which has a significant impact on the surface water resource availability of the catchment. The reduction in stream flow volume directly related to decreasing rainfall would be attributed due to climate change impacts.
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Keywords
Climate change, GCM, HBV-Light, Catchment, CORDEX, RCPs