As scientists worry about the prospect of a catastrophic flood from Lake Sarez in the Pamir Mountains (see main text), agricultural communities on the plains below face a very different problem: increasing competition for fresh water, a situation that might be eased, experts say, if Lake Sarez could be tapped and its surplus water distributed.
Water scarcity is not the only woe. The people of Ferghana Valley in northwest Tajikistan are trying to bail out of a vast inundation, the belated consequence of a Soviet project called the Kayrakkum Dam, completed in 1956. As its reservoir filled, the water table of the surrounding land rose, infiltrating homes and spoiling crops. Engineers installed a drainage system to pump water back into the Kayrakkum reservoir. But now many of the pumps have broken down. Across 30,000 waterlogged hectares, sewage is backing up, salt has risen to the surface and is ruining fields, and homes are riddled with mildew, says civil engineer Akhrorov Akhatjon of the Ferghana Valley Water Resources Management Project. "The problem is getting worse," he says. The government lacks the resources to fix the drainage system, and villagers are too impoverished to relocate. A handful of people have had the means to rebuild homes on 3-meter-high foundations, but most simply endure the swampy conditions. "We're worried about the disease risk of poor sanitation," Akhatjon says. "It's a perilous situation."
Along the Tajik-Uzbek border, meanwhile, a perpetual squabble over water and energy resources is growing tenser. In winter as hydropower reservoirs in Tajikistan drop too low to generate power, Uzbekistan has accused Tajikistan of siphoning electricity from Central Asia's shared grid. This month, Uzbekistan pulled out of the grid—a move that has provoked talk of retaliation. "If [Uzbeks] don't want to give us electricity during winter, why should we give them water?" asks Sharifov Gul, a chief engineer in Tajikistan's water ministry.
Turning off the spigot is easier said than done. The source of most of Central Asia's water is rivers flowing from glacier fields in mountainous Kyrgyzstan and Tajikistan. There's little now that either country can do to stem the flow into Kazakhstan, Turkmenistan, and Uzbekistan. But that could soon change. Tajikistan is building the world's tallest artificial dam, Roghun, on the Syr Darya River. The 3.6-gigawatt hydropower station would make Tajikistan self-sufficient in electricity. Uzbekistan has opposed the 335-meter-high dam, arguing that Tajikistan might use Roghun to restrict downstream releases. That could devastate agriculture in Uzbekistan, whose cotton and wheat fields depend on irrigation from the Syr Darya and the Amu Darya. Gul insists that's not Tajikistan's intention: In fact, he says, Roghun could supply electricity to neighboring countries.
The most notorious example of poor management, perhaps, is the diversion of water a half-century ago from the Amu Darya and Syr Darya to irrigate cotton fields in Turkmenistan and Uzbekistan. The irrigation canals constantly hemorrhage water through their beds, while a substantial fraction of water also evaporates. By the 1970s, the Amu Darya no longer reached the Aral Sea. The shrinking sea grew saltier and fisheries were devastated; a Kazakh effort is replenishing part of the sea (Science, 14 April 2006, p. 183).
A fresh concern is the retreat of Central Asia's glaciers as temperatures rise. Both the Amu Darya and Syr Darya depend on glacier runoff to provide a stable flow in summer, says Daene McKinney, a civil engineering professor at the University of Texas, Austin. "Decreased glacier mass will likely cause this high level of dependable base flow to become more erratic, requiring more efficient water management," he says. The Amu Darya is expected to be the hardest hit, says Victor Dukhovny, director of the Scientific Information Centre of the Interstate Commission for Water Coordination of Central Asia in Tashkent. As a result, he says, there is already a "strong movement to water saving."
In a taste of hardships to come, Central Asia experienced a prolonged drought last year that resulted in water shortages. In response, Tajikistan stepped up construction of Roghun, a project started by the Soviets in the 1970s. It spent $150 million this year and plans a similar expenditure in 2010, and now has a 7000-strong work force at the site. To speed up the project, Tajikistan President Emomali Rahmon this month called on every Tajik family who could afford it to buy shares in Roghun.
The most urgent need at present, argues Dukhovny, is stronger water governance to mediate the struggle between hydropower companies intent on controlling water and agricultural concerns that have an inalienable right to water. Ministers of Central Asian nations meet every 3 months to discuss how to divvy up water under an existing treaty. But as resources grow scarcer, transboundary disputes are bound to grow more frequent. Because "international water law is very weak," Dukhovny says, it might take the intervention of the U.N. Security Council to forge a lasting solution.