Africa's great lakes are drying up: Africa has more than 30,000 cubic kilometres of water in its 677 lakes, more than anywhere else in the world. Vast numbers of people depend for their livelihoods on African lakes but there has been an alarming drop in the water levels of some of the most famous such as Lake Victoria. Neil Ford examines the causes of this new water crisis.

As African Business reported last month, water levels on Lake Victoria have fallen alarmingly, resulting in both lower electricity production and power rationing in Uganda. Explanations for the fall have largely focused on the use of water by the power sector but while this may play a role, there is a great deal of evidence pointing towards a long-term problem.

Water levels are falling on many lakes across the region and apart from the obvious devastating environmental impact, East African economies could also be affected by electricity shortages and unusable port facilities.

An environmental NGO, the International Rivers Network, claimed in February that Uganda had been taking 55% more water from Lake Victoria than agreed under the existing legal framework. Rising demand for electricity has certainly increased the pressure on the country's hydroelectric facilities and the NGO claimed that this accounted for around half the reduction in the lake level, which is the lowest since the 1920s. It is claimed that the current drought is responsible for the other 50%.

Kampala has denied the charges but the International Rivers Network's claims may hold some substance, as the struggle for control of the Nile Basin's waters is a long-running saga.

Under the existing web of colonial era agreements, the lion's share of water resources in the entire watershed are for Egyptian use, while most of the remainder is allocated to Sudan. With Ethiopia, Eritrea, Uganda, Tanzania, Kenya, Rwanda, Burundi and Democratic Republic of Congo also lying within the watershed, the existing deal is blatantly unfair.

Despite its historical dependence on the river, the Egyptian government has begun to negotiate over the division of the Nile waters in recent years. It recognises that the existing situation is untenable and although it is loath to give up its rights, Cairo acknowledges that it is difficult to restrict the development of upstream hydroelectric and irrigation schemes unless it is prepared to compromise.

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However, it may be unfair to lay the blame for Lake Victoria's problems entirely at Uganda's door. Water levels have fallen by two metres since independence, which is almost the same reduction as on Lake Tanganyika. Yet the latter is not affected by large hydro schemes, so the cause of the fall must lie elsewhere. While the current drought has been devastating enough, it could form part of a trend of lower rainfall across eastern Africa.

Hydro schemes also cannot be blamed for the three-metre drop on Kenya's second biggest lake, Lake Naivasha. The environmentally important site, which was regarded as one of the 10 most important sites for birds in the world, is now half its original size and the regional ecosystem has been badly affected.

At the 4th World Water Forum in Mexico in March, David Harper of the University of Leicester, said that the unsustainable extraction of water for residential, industrial and agricultural use; overgrazing of riparian vegetation and the introduction of exotic species had all affected the lake.

He continued: "These three factors combined mean the lake that remains has no natural buffer against the inflow of sediment and nutrients. The ever smaller lake is becoming an over enriched muddy pool, which shortly will become unusable through the development of toxic blue green algae blooms. Its inflowing rivers, formerly sparkling and permanent are now muddy and unpredictable."

The economic cost

Ship and port operators on Lake Victoria have already complained of the impact on their operations. The volume of freight transported by ship on the lake has dropped by 70% over the past year, as vessels have found it increasingly difficult to dock at the lake ports of Jinja, Kisumu, Mwanza and Port Bell.

The marine superintendent for Kenya Railways, Vitalis Leo, commented: "Besides huge business losses, we are sitting on a time bomb because a major accident could occur at these ports because of the low water levels."

Other officials have warned that port closures are possible.

Lake Victoria has long been a vital link in East Africa's transport infrastructure and it has been made the centrepiece of efforts to promote trade and regional integration within the East African Community (EAC). Rail lines connect the lake ports with the main east coast ports of Dar es Salaam and Mombasa, so rail cargo can easily be transported between Tanzania, Kenya and Uganda once it reaches the lake.

Similar problems could hit Lake Tanganyika, which is also served by the rail link with Dar es Salaam. Trade between Burundi, Democratic Republic of Congo, Tanzania and Zambia is carried out on the lake but a Burundian government spokesperson has indicated that operations at the country's main port, Bujumbura, have been hit by insufficient water levels in the harbour. He blamed global warming and deforestation for the lower water levels that have been recorded. Burundi relies on the port for up to 90% of its imports, so the government is particularly concerned.

Bujumbura port's managing director, Methode Shirambere, has warned that the port could be forced to close sometime during the first half of this year. Shirambere said that part of the dockside has already been closed because of the risk of large vessels running aground.

He added: "The dropping of water levels has been going on for the last 14 years, but was expedited by the destruction of a natural dam on Rukuga River which flows from the DRC to Lake Tanganyika." Deforestation has been worse in Burundi than in some other African countries because wooded areas were set alight during the civil war to make them less attractive to rebels. The Burundian government has suggested diverting the River Ntahangwa to provide extra water.

Ministers from Kenya, Tanzania, Uganda and Rwanda were expected to hold a summit in conjunction with the World Bank in April to consider how to tackle the lack of water in Lake Victoria. A World Bank statement read: "This is a very complex situation, given the environmental, social and economic importance of Lake Victoria, the prolonged period of drought, and significant hydropower shortfalls throughout the region. Affected countries are also looking for ways to establish regional mechanisms for more effective water management, expected to be supported by a second phase of the Lake Victoria Environmental Management Project."

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It continued: "In addition, there are World Bank projects in the pipeline that will contribute to better water management in the upper catchment areas close to the lake, thereby benefiting the lake indirectly."

The World Bank and other funding bodies have agreed to help counter the loss of hydroelectric capacity in the longer term by investing in power sector transmission infrastructure and assisting in the development of new thermal power plants.

However, there are indications that the fall in lake levels is not restricted to eastern Africa. A UN report, entitled The Atlas of African Lakes, argues that over-use and climate change have resulted in lower water levels across the continent. Published in October, the report includes satellite images of many African lakes, including Lake Nakuru in Kenya and Lake Chad, taken over several decades, that clearly demonstrate massive shrinkage.

Africa's rapidly growing population inherently puts more pressure on water resources and the UN document cites higher population densities around Lake Victoria as a major cause of that lake's problems.

A spokesperson for the United Nations Environment Programme (UNEP), commented: "The atlas shows that massive changes are happening in African lakes. There are huge population pressures on all lake systems in Africa and unless there is some way for people there to find alternative ways of living, they will continue to be under pressure. Lakes are the lifeblood of millions and millions of Africans. We are not going to meet the Millennium Development Goals on water or health unless we protect them."

UNEP listed the main causes of falling lake levels in Africa as: natural seasonal fluctuations in rainfall, climate change, pollution, over-fishing, desertification, the presence of invasive species, inappropriate dam construction and a range of local issues.

Although Africa is subject to massive water stresses, its 677 major lakes contain 30,000 cubic kilometres of water: according to the UN report, this is more than any other continent. With such a hugely important natural resource, it is therefore vital that measures are taken to maintain lake levels. In the longer term, water-borne trade and hydroelectric production will be affected, so the economic impact could be just as great as the environmental devastation if the problem is not tackled.