Catch a view of the full-size Lake Turkana while you can (Image: Nigel Pavitt/Getty)
Kenya’s Lake Turkana is vital for local wildlife and livelihoods, but Africa’s tallest dam is going to choke it to provide much-needed power and water
FOUR is an unlucky number for lakes. Once the fourth largest in the world, the Aral Sea is now a shadow of its former self. As the then Soviet Union diverted the rivers that feed it to grow cotton, its shoreline retreated by more than 100 kilometres in places. Today, in the middle of the dried-up lake bed, lie two small hyper-saline lakes. All around, climates are more extreme, dust storms spread salt across the land, a rich fishery that once supported a fleet of trawlers has disappeared entirely – and millions of people left high and dry have been forced to move elsewhere.
Advertisement
What started happening in the Soviet Union half a century ago looks set to happen again, this time to Africa’s fourth largest lake and the biggest desert lake in the world, Lake Turkana. European explorers nicknamed it the Jade Sea thanks to its turquoise waters, which stretch for 250 kilometres in northern . There are many reasons to protect it. But starting this year, Lake Turkana is timetabled to shrivel and die.
The problem is that the source of almost all of Lake Turkana’s water is across Kenya’s northern border in Ethiopia, from the river Omo. Now plans to capture most of that flow to generate hydroelectricity and irrigate plantations of sugar and other thirsty crops. Kenya has barely raised a whimper about its larger neighbour, but researchers warn that what is about to happen is a hydrological, ecological and humanitarian catastrophe.
Lake Turkana takes its name from the people who live on the western shore. It is likely to lose at least half of its volume and could be reduced to two small, salty sumps. Five national parks will be wrecked and half a million people face the loss of ecosystems that sustain their precarious existence in a remote corner of Africa.
It is clear why Ethiopia wants to harness its water. Parts of the country are dangerously dry. In the 1970s and 1980s, Ethiopia suffered catastrophic droughts that left hundreds of thousands of people dead. Yet much of its central highlands are as wet as Scotland, and the government wants to tap this water to improve the lives of its 96 million citizens. That means damming the Omo – it is a resource too valuable to be ignored.
So later this year, in a steep canyon 600 kilometres north of Lake Turkana, engineers will complete construction and begin capturing the Omo’s flow behind Africa’s tallest dam (see map).
The 243-metre-tall Gilgel Gibe III dam is the latest and biggest in a series of five planned for the river. Over the next two or three years, a reservoir 150 kilometres long will fill behind the concrete barrier. The dam will capture almost two-thirds of the water from the Omo that would otherwise reach Lake Turkana. The remaining third is provided by tributaries such as the Mago, which enter the Omo downriver of the dam. This is disastrous news for the lake because about nine-tenths of its water comes from the Omo.
The water level in Lake Turkana depends on the balance between inflow from the Omo and evaporation from the lake’s surface. The unrelenting Kenyan sun takes 2.5 metres a year from the lake’s depth. Sean Avery, a Nairobi-based consultant with over 30 years’ experience working with dam builders in Africa, has . He calculates that as the new reservoir fills, Lake Turkana’s water level will drop by at least 2 metres.
That is not so bad. A decade ago, the dam’s designers promised that, after the reservoir filled to capacity, the water released through its Chinese-built turbines would be as great as before. Eventually the lake would recover to its former level.
But that was then. Three years ago, with dam construction already well under way, the Ethiopian government suddenly announced big plans for the water after it leaves the dam. By regulating the river’s flow, the dam allows the development of downstream irrigation works that the government intends will capture much of its flow. First up – and already under construction – is the 175,000-hectare Kuraz sugar plantation, named after the homeland of the local Daasanach people that it will largely take over. And the government has also earmarked almost 300,000 hectares of the lower Omo valley for commercial agriculture.
This is a massive change to an unfenced landscape of bush, woodland and open cattle pasture. Now, as the fences go up and irrigation canals are dug, both wildlife and local tribes will lose out, with many people forcibly resettled. Almost half a million hectares will come under the plough and the Omo will be systematically emptied.
The Ethiopian government has never published an environmental assessment of the impact of the farms and their water abstractions. But Avery estimates that – depending on the pace of development, the efficiency of the irrigation and how much water returns to the river from field drainage – the Kuraz sugar project alone could permanently take at least 30 per cent of the river’s flow. The other planned farms would increase the take to 50 per cent or more.
The Ethiopian government says the country cannot afford not to have the Gilgel Gibe III dam. And it comes as no surprise that the state-owned electric company and claim that the environmental impact of the dam will be minimal.
But the hydrology is inescapable. Lake Turkana currently loses 16 trillion litres of water to evaporation each year – enough to empty the entire lake in just 11 years. If inflow from the Omo is reduced by as much as seems likely, the lake will shrink drastically, eventually finding a new stable state where evaporation from a reduced surface area balances the reduced inflow. Avery predicts that a 50 per cent cut in inflow would ultimately reduce the lake’s volume by half and drop the water level by 20 metres.
“Lake Turkana loses 16 trillion litres of water to evaporation each year”
The lake will dry out first in the shallow north. The Omo delta, whose reed beds and woodlands play host to hippos, crocodiles and water birds, will dry out after just a 5-metre drop in water level. A 10-metre decline would mimic what happened during droughts in the Ethiopian highlands between 1975 and 1993, when around 70 per cent of life in the lake was lost. Anything more than a 20-metre drop would turn the lake into two small, very salty and very alkaline lakes occupying the deepest parts of the valley, one fed from the residual Omo and the other from two small rivers that drain into the south of the lake, the Kerio and Turkwel.
But falling lake levels are not the only issue. From the moment the dam closes, the seasonal cycles of river flow, driven by the autumn wet season in the highlands, will be replaced by fluctuations determined by Ethiopia’s electricity demands. That will dramatically diminish the river’s annual flood downstream of the dam site. Till now, the average flow in the peak month on the river has been eight times as high as the lowest monthly flow. The dam’s designers predict that after the dam is operational, the peak flow will be just twice that of the slowest flow.
Almost all hydroelectric dams round the world have a similar smoothing effect on flood cycles. The purpose of their large storage reservoirs is, after all, to hold back flood flows to ensure there is always water to pour through the turbines. But the fact that the Omo drains into an inland lake rather than the ocean, coupled with Lake Turkana’s almost total reliance on the river, means that the impacts downstream of Gilgel Gibe III will be much greater than for most dams.
The Ethiopian government argues that smoothing the river’s flow is a good thing as it would prevent the kind of flood disaster that happened on the lower Omo in 2006, when more than a hundred people drowned. The dam’s designers claim the attenuated flood will benefit the lake’s ecosystems, too. But critics of the project say the 2006 flood was unusual, a once-in-100-year event. Most of the time, the annual flood pulse is vital for both nature and human livelihoods along the river. It wets floodplains that sustain pastures, as well as extensive woodlands.
And the positive impact of the flood pulse on the lake’s ecosystems is even greater, says , a fish biologist from the University of Bergen in Norway, who carried out a landmark investigation of the lake’s fisheries in the 1980s. The pulse brings into the lake waters rich in sediment, organic matter and nutrients, much of which it gathers from the floodplain. These goodies stimulate an orgy of fish breeding and growth, which in turn drives an ecosystem that encouraged the Kenyan government to create , covering Sibiloi on the lake’s eastern shore, the South Island and the Central Island.
Today, the lake has markedly fewer crocodiles than half a century ago, when it had the largest breeding colony of Nile crocodiles in the world. And hippos are now mostly confined to the Sibiloi National Park. But venomous snakes, including cobras, puff adders and saw-scaled vipers, still lurk on the shores. There is abundant bird life and fish aplenty, with about 60 fish species, many of them endemic.
One of the richest fishing areas has long been the shallow Ferguson’s Gulf on the Lake Turkana’s western shore. Though occupying less than 0.5 per cent of the lake, it has as many as half the lake’s inshore fish, says Kolding. During years with a strong flood pulse, up to 16,000 tonnes of tilapia are caught in the gulf. It remains a fecund fishing ground today, with smoked fish sold at beach markets and shipped across Kenya and as far as the Congo.
If the lake level falls more than 3 metres, Ferguson’s Gulf will dry out and this fishery will disappear. Others may emerge in new shallows, but they are unlikely to be as productive without the flood pulse, says Kolding. Such impacts are invisible to the authorities in Ethiopia, who have never publicly reported on the likely consequences of their activities over the border in Kenya.
In response to criticisms, the Ethiopian government has recently promised an ecological flood release of a million litres per second for 10 days during September. That would be a substantial lifeline, says Avery, if it actually reached the lake. But he and other critics simply don’t believe it will. In practice, the water will always be needed for some other purpose.
The bottom line is that the Ethiopian government is bent on modernising this previously untouched corner of the country, and bringing its many different ethnic groups into the national mainstream. That is mostly good news. There are new roads, new clinics, programmes to fight the tsetse fly, and an airport. Cattle herders such as the Mursi – the last tribe in Africa in which women routinely wear large plates through their lips – have been promised regular jobs on the farms.
The massive sugar plantation is part of a plan to make Ethiopia one of the world’s top 10 sugar exporters. The Gilgel Gibe III power plant will generate 1870 MW of electricity, thereby doubling the generating capability of a country in which only a third of people have access to mains power. Ethiopia is offering to sell its neighbours a share of the power it will generate, with the World Bank funding a 1000-kilometre power line from the dam to Kenya. And yet locals have little choice in the matter, according to Human Rights Watch in New York, which has documented their .
The dam and sugar plantation represent the development dilemma. , an Ethiopian water-resource specialist, thinks that on balance the Omo valley developments are a good thing. “We should not be naive,” he says. “Development sometimes goes against the local community, and we have to choose between environmental flows and electricity flows.”
But the tragedy is that Ethiopia – a country so determined not to repeat its nightmare of a generation ago, when it suffered so badly from drought and spreading deserts – is set to protect itself in ways that will dispossess some of its own people, while creating more droughts, and spreading more deserts, over the border in northern Kenya.
The shimmering Jade Sea looks set to lose its shine forever.
Leader: “Break electricity addiction to win the power struggle“
Kenya’s colossal cache
Last year came news of a hidden water bonanza in Kenya. Analysis of remote sensing data identified large underground water reserves west of Lake Turkana. According to Radar Technologies International, which studied the area for UNESCO, the is thought to contain about 200 trillion litres of water, roughly the same as sits in Lake Turkana. “This water opens a door to a more prosperous future for the people of Turkana and the nation as a whole,” said Kenyan environment minister Judi Wakhungu last year.
Perhaps the emptying of the river Omo doesn’t matter. Not so fast, says Sean Avery, a consultant who studies the hydrology of the entire region and points to some problems. Much of the water is below 100 metres deep, so pumping it to the surface will be expensive. And its quality remains uncertain. Moreover, the rate of recharge is low. Rainwater flowing in from the surrounding highlands adds an estimated 1.2 trillion litres to the Lotikipi aquifer each year and 3.4 trillion litres to all the aquifers in the Turkana region. But even the higher figure is just one-fifth of the annual natural flow of the Omo into Lake Turkana.
This article appeared in print under the headline “Dam nation”
