A Uganda energy official has released a paper explaining that extreme drought, and not excessive hydropower generation, has caused a major decline in the water level of Lake Victoria, the largest African lake and a source of the Nile River.
Commissioner Paul Mubiru of Uganda’s Energy Resources Dept. analyzed the water level decline in the face of accusations leveled at the 180-MW Nalubaale and 200-MW Kiira hydroelectric projects, at Jinja on Lake Victoria’s outlet, the Victoria Nile River. Reports had alleged excessive power generation was responsible for 55 percent of the decline in the lake, which has fallen as much as six feet in the past three years.
Mubiri found that average outflows for 2001-2005 were slightly less than the 40-year average prior to the commissioning of the Kiira plant. For two of those years, 2004 and 2005, the average flows were slightly above the 40-year average.
Mubiri calculated that outflows from the lake accounted for just under 11 percent of the water lost, with 3.68 percent due to excess flow in 2004-2005. He said that compares to 89 percent of the water being lost by evaporation, a factor that he said has been greatly underestimated. That, coupled with significantly lower inflows due to drought, led to reduced lake levels. (HNN 12/13/06)
Reducing hydro generation did not stem water decline
�The reduction of Victoria Nile outflows at Jinja, which have been implemented (at the hydro projects) so far, has not led to the recovery of the lake,� he said. �Despite outflow reductions, the lake level continues to decline as if nothing had happened. This trend is only reversed when a rainy season sets in.�
Further, Mubiri noted, other East African lakes have been hit hard by drought, including Lake Tanganyika, which had dropped more than five feet.
The energy official said the medium-term solution to the resulting power shortage is construction of the 250-MW Bujagali Falls and 250-MW Karuma hydroelectric projects, proposed by Uganda for the Victoria Nile, as well as small hydro, biomass, solar, and wind power. (HNN 11/28/06)
�Issues have been raised on the economic viability of the Victoria Nile hydropower projects downstream of Kiira/Nalubaale in view of the current hydrological conditions,� Mubiri said. �� However, the three- or four-year dry spell is no justification for Uganda to abandon the Victoria Nile hydropower sites.�
Mubiri said Bujagali Falls and Karuma are the least-cost options and are sized for long-term outflows.