Modeling the Nile Basin under Climatic Change

Abstract

This paper presents the development and application of a monthly water balance model of the Nile River basin (WBNILE) for assessing potential climatic change impacts on Nile runoff. The WBNILE model consists of 12 Nile subcatchments, including characterization of the lakes region of equatorial Africa and the Sudd swamp. The model uses mean monthly climate variables of precipitation, temperature, relative humidity, and sunshine hours, and each basin is calibrated from observed monthly averaged discharge. Areally averaged temperature and precipitation changes from five global circulation models (GCMs) were imposed on each subbasin for assessing climate change impacts on runoff. Results showed the sensitivity of the basin to climate fluctuations, because four of five GCMs predicted significantly larger flows in equatorial Africa and the expansion of the Sudd swamps, whereas there was a range of results for the Ethiopian highlands of the Blue Nile and Atbara basins depending on the GCM scenario.