Lake Victoria’s Water Budget and the Potential Effects of Climate Change in the 21st Century

Abstract

This paper presents the Lake Victoria water budget for the period 1950-2004 and findings of a study on potential climate change impact on the lake’s Hydrology through the 21st Century. The mass balance components are computed from measured and simulated data. A2 and B2 emission scenarios of the Special Report on Emissions Scenarios are considered in the climate change assessment. Results show that rainfall and Evaporation by far exceed catchment inflow and outflow. Rainfall over the lake exceeds evaporation by a factor of 0.1 whereas outflow exceeds inflow by a factor of 0.27. Due to climate change, increase in temperature of 4-5oC and 2-3oC are expected by the end of the 21st century under the A2 and B2 emission scenarios respectively. There is very significant downward trend in the lake Net Basin Supply reducing by up to 50%) by the end of the Century. Towards the end of the 21st century, the lake is likely to experience more frequent and prolonged droughts implying lower lake levels

Key words: Lake Victoria, Water budget, climate change, emission scenarios.