Lake Victoria is the largest lake in Africa and one of the two major sources of the Nile River. The water level of Lake Victoria is determined by its water balance, consisting of precipitation on the lake, evaporation from the lake, inflow from tributary rivers and lake outflow, controlled by two hydropower dams. Due to scarcity of in-situ observations, previous estimates of individual water balance terms are characterised by substantial uncertainties, which makes that the water balance is often not closed independently. Here we present a water balance model for Lake Victoria, using state-of-the-art remote sensing observations, high resolution reanalysis downscaling and outflow values recorded at the dam. The uncalibrated computation of the individual water balance terms yield lake level fluctuations that closely match the levels retrieved from satellite altimetry. Precipitation is the main cause of seasonal and inter-annual lake level fluctuations, and on average causes the lake level to rise from May to July and to fall from August to December. Finally, our results indicate that the 2004&ndash;2005 drop in lake level can be attributed about half to a drought in the Lake Victoria Basin and about half to an enhanced outflow, highlighting the sensitivity of the lake level to human operations at the outflow dam.
Vanderkelen, I., Van Lipzig, N. P. M., & Thiery, W. (2018). Modelling the water balance of Lake Victoria (East Africa)-Part 1: Observational analysis. Hydrology and Earth System Sciences, 22(10), 5509–5525. https://doi.org/10.5194/hess-22-5509-2018