Projected climate change impacts on hydroelectric energy and coastal systems surrounding Lake Victoria, East Africa

The flow of the White Nile over Eastern Africa and the productivity of its hydroelectric power dams is primarily determined by the level of Lake Victoria. Nalubaale Dam (originally called Owen Falls Dam), located at the city of Jinja, Uganda on the shores of the largest lake in Africa, was the first (1959) major hydroelectric plant to be constructed in the region. Kiira dam was commissioned in 2000. Bujagali dam is expected to be commissioned in 2011, while Murchison Falls dam in Uganda and several other dams in Sudan and Egypt are in the planning phase. The flow of the White Nile and the productivity of these dams are primarily determined by the level of Lake Victoria. The temporal variability of the level is in turn primarily determined by the rainfall variability in the basin.

The only outlet from the lake is at Nalubaale and Kiira dams. While the outflow has followed the ′Agreed Curve′ where the amount of water released through the dams is equal to the amount that would have flowed out of the lake did not exist, one of the hydrological indices used for decision making in regulating hydroelectric power production over the lower White Nile is ′low′ and ′high′ Lake Victoria hydrology. Low hydrology corresponds to the accumulative level of the lake depth at the end of each year satisfying the condition, 10.64 meters < lake level < 12.14 meters (mean water release target of 687 m³/s), while high hydrology corresponds to lake level > 12.14 meters (mean water release target of 1247 m³/s). The objective of this study is to determine if climate change will cause sustained shifts between the two regimes.

Climate change projections based on the downscaling of IPCC global products using RegCM3 & PRECIS regional climate model indicate an increase of several meters in the lake's level above the current state in this century. The Eastern Africa countries could benefit from higher potential of hydroelectric power as a result of climate change. Further analysis using GIS indicates that climate change could make the road network infrastructure as well as other infrastructure near the coastline prone to flooding. This and other potential impacts must be taken into account in planning for future social-economic development for this part of Eastern Africa.