Engineers in Uganda are secretly draining Lake Victoria to generate electricity, flouting an international agreement to protect the world’s second-largest freshwater lake, according to a new report.
Daniel Kull, a hydrologist with the United Nations’s International Strategy for Disaster Reduction in Nairobi, Kenya, says the country is directing more of the lake’s waters than agreed 50 years ago under an international pact.
Kull has calculated that the water level in the lake is almost half a metre lower than it should be. Official reports on the hydroelectric dam operations published for March and November last year show that water releases were almost twice their permitted rates, he says. The report is published by a United States environmental lobby group, International Rivers Network.
Frank Muramuzi, of Uganda’s National Association of Professional Environmentalists, told New Scientist magazine: ”This dam complex is pulling the plug on Lake Victoria.”
The lake, which covers an area that includes Uganda, Kenya and Tanzania, supports 30-million people. Water levels have plummeted since 2003 and are now at an 80-year low.
About 3% of the lake’s volume has disappeared, leaving towns running low on water and international ferries stranded far from their jetties.
There have also been disruptions to electricity supply, and the company that operates the dams, the Uganda Electricity Generating Company, has blamed this on a 10% to 15% decline in rainfall across the lake’s catchment area during the past two years. But Kull says the dams are as much to blame as the drought. If the dams had operated as agreed, he says, the drought would have accounted for only half the water loss.
British colonial engineers built the first dam in 1954. The Owens Falls Dam, now renamed the Nalubaale Dam, effectively transformed the lake into a giant hydroelectric reservoir. It was constructed on the site of the lake’s only outlet, a natural weir at Jinja in Uganda that fed the Victoria Nile River.
It was agreed that the amount of water flowing through the turbines should mimic the amount that used to drain over the weir.
The formula is known as the ”agreed curve” and sets a maximum flow of between 300 and 1 700 cubic metres a second, depending on the water level in the lake. The agreed curve remains the basis for a treaty with Egypt, the ultimate user of most of the Nile’s water.
The problems began in 2002 when Uganda finished building a second hydropower complex. Soon afterwards, local people noticed the water level falling. Kull estimates that over the past two years the two Ugandan dams have released water at an average of almost 1 250 cubic metres a second — 55% more than is permitted given current water levels.
Lake Victoria was one of dozens of threatened freshwater supplies across Africa highlighted in a separate UN report in November. Satellite images revealed an unprecedented deterioration in all of the continent’s 677 biggest lakes, some of which could be reduced to swamps within decades, the UN warned. — Guardian Unlimited Â