By Sandra Postel
Over the last century, the construction of big dams to generate power, supply water and control floods has unleashed a damaging cascade of social and environmental consequences – including the destruction of fisheries, subsistence farmlands, homes and communities.
More than 470 million people around the world are estimated to be suffering from these and other downsides of dams, often with little or no compensation for their lost livelihoods.
The Omo traverses the highlands of southern Ethiopia before it empties into the lake in northern Kenya.
The Ethiopian Government views the Gibe III Dam, under construction since 2006 and now about half complete, as essential to its drive for economic development. In addition to generating electricity for domestic use and export to neighboring Kenya, the dam will supply water to vast agro-industrial schemes, including plantations of sugar cane for biofuels production.
But without attention to the peoples, wildlife and ecosystems affected by this massive project, the cost of progress may be far too great, according to a study released this week by International Rivers, an environmental and human rights organization based in Berkeley, California.
If Ethiopia completes the Gibe III Dam and moves ahead with large-scale irrigation in the lower Omo Basin, “the result will be a cascade of hydrological, ecological and socio-economic impacts that will generate a region-wide crisis for indigenous livelihoods and biodiversity and thoroughly destabilize the Ethiopia-Kenyan borderlands around Lake Turkana,” says the report, written by a natural scientist with many years of field experience in the region who wishes to remain anonymous.
Numerous indigenous peoples, including those of the Bodi, Karo, Kwegu, and Mursi tribes, rely on the natural flood cycles of the Omo for their sustainable practices of flood-recession farming, fishing and livestock grazing. Like generations of their forebears, they plant sorghum, maize and beans in the riverside soils after the yearly flood, relying on the moisture and nutrient-rich sediment the Omo deposits each year.
That cycle of flooding will disappear if the dam is completed, because the river’s natural rhythms will be replaced by flows regulated to optimize the production of hydropower and to deliver irrigation water to industrial-scale farms.
“When we talk about the Omo River we are talking about our life,” said the chief of the Karo people to Mark Angelo, chair of the Rivers Institute at the British Columbia Institute of Technology. “The Omo River is everything to us. But we don’t have a say.” (Read Angelo’s article and see the video here.)
The lower Omo Valley is also the last unspoiled biodiversity hot spot in southwestern Ethiopia and an area crucial for elephant and other large mammal migrations. Harm to wildlife from the dam-based schemes could be substantial, since among the areas slated for large-scale plantation-style agriculture is a sizeable portion of the Omo-Tama-Mago complex of protected areas, Ethiopia’s most important wildlife territory.
Lake Turkana, situated at the northern end of Kenya’s Great Rift Valley and one of the oldest lakes on Earth, could shrink dramatically if Gibe III is completed. The lake currently receives nearly 90 percent of its inflow from the Omo. Without the river’s yearly supply, Lake Turkana would steadily lose water, because evaporation would no longer be balanced by inflows. Each year, about 7 percent of the lake’s total volume evaporates under the hot desert sun.
Between the Omo water stored in the Gibe III Dam’s reservoir and diverted to the large irrigated plantation schemes now under development in the lower Omo Valley, the level of Lake Turkana could drop by as much as 22 meters (72 feet), according to the study. Given that the lake’s average depth is 30 meters, such a drop would alter its ecology, salinity and habitat immensely.
Indeed, the devastation to the lake’s ecology and fisheries could rival that of Central Asia’s Aral Sea, which has lost more than 80 percent of its volume of water through excessive diversions of the two rivers that flow into it.
Gibe III, expected to cost about $2 billion (which is likely an underestimate, given the history of dam cost-overruns), is a public–private partnership between the state-run Ethiopian Electric Power Corporation and the Italian engineering firm Salini Costruttori.
International Rivers and Friends of Lake Turkana are calling for a halt to construction until there is a thorough and scientifically sound assessment of how the dam and irrigation projects will harm Lake Turkana, as well as a plan to ensure the lake does not collapse ecologically.
As for the Omo, the government earlier proposed to mitigate the effects of the dam with a “controlled” flood, executed by releasing water from the dam’s reservoir for ten days. The idea would be to mimic the Omo’s historic natural flood, which is so important to the indigenous peoples’ livelihoods.
However, an independent review of the Gibe III project, commissioned by the European Investment Bank, determined that the planned artificial flood had not been adequately studied to determine its effectiveness. But given the rapid growth of irrigation in the basin, it is likely the dam would not be managed to maintain ecosystem functions. As the new report states, “The designation of Omo riverbank lands for industrial agriculture immediately makes clear that artificial floods for ecological benefits will not be released as proposed, since these would harm the estates.”
Ethiopia remains one of the world’s poorest nations. There is no begrudging its quest for economic advancement.
But there are alternatives to grabbing land and water from indigenous tribes who have lived and farmed sustainably in the region for hundreds of years, and to destroying so much of the country’s natural and cultural heritage for the sake of export-oriented agriculture that will do little to improve the lives of the very poor.
The government should halt the development of Gibe III until its full social, political and ecological ramifications are understood, and until the principles set forth by the World Commission on Dams for dam project assessment and compensation are fully taken into account.
*Note: I joined fifteen other scientists, including Richard Leakey of the Turkana Basin Institute, David Turton of Oxford University’s African Studies Centre, Kate Showers of the University of Sussex, and Eric Odada of the University of Nairobi, in endorsing this study.
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Sandra Postel is director of the Global Water Policy Project and Freshwater Fellow of the National Geographic Society. She is the author of several acclaimed books, including the award-winning Last Oasis, a Pew Scholar in Conservation and the Environment, and one of the “Scientific American 50.”
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