Impacts of climate change on peak streamflow in Kakia-Esamburmbur Sub-catchment of Enkare Narok River catchment, Kenya

Climate change has shown significant effects on catchment water balance mainly linked to hydrological extremes. Hence,the objective of this study was to predict the impacts of climate change on peak streamflow in flood prone Kakia-Esamburmbursub-catchment of Narok County, Kenya. Soil and Water Assessment Tool (SWAT) was used to simulate the impacts of climatechange on peak streamflow, whereas Gumbel distribution was used to project the peak flows (for base simulation and two climatechange periods). Three climate change scenarios were simulated based on International Panel on Climate Change (IPCC) projectedfor the East Africa region. These scenarios were Representative Concentration Pathway 2.6 (RCP2.6), RCP4.5 and RCP8.5.Gumbel distribution method was used to determine the peaks of the simulated streamflow corresponding to 2, 5, 10, 50, and 100-year return periods (T). Model performance values obtained for calibration and validation were Nash-Sutcliffe efficiency (NSE):0.57 and 0.52, coefficient of determination (R 2 ): 0.61 and 0.66, and percent bias (PBIAS): 5.8% and 24%. The simulation showedthat the change in peak flood will respectively increase by 6.7% to 8.2% for Period 1 and between 18.5% and 24.3% for Period 2for floods of return periods between 2 and 100 years. The findings of this study provide useful insights for developing flood riskmanagement strategies for Narok town.