REGIONAL CLIMATE CHANGE AND ITS IMPACTS ON FUTURE DISCHARGES AND FLOW CHARACTERISTICS OF THE NYANDO BASIN, KENYA

Abstract

Using a physically-based distributed hydrological model (WEB-DHM), this study investigated the likely impacts of climate change on Nyando river basin in Kenya. Analysis of the East African regional climate indicates a weakening in the westerlies and a projected increase in precipitation. A simple statistical method was applied to downscale General Circulation Model (GCM) precipitation to the basin scale. At this scale the GCMs predict a relatively drier basin with two of the selected models projecting a 9% decrease in annual rainfall. The bias-corrected and downscaled GCM precipitation data was then used to drive the WEB-DHM to project future changes in streamflow. There′s a projected decrease in annual discharge with a likely increase of floods in the months of July and August.