But a booming population and growing fears about climate change have governments once again studying dams, this time to create huge reservoirs to capture more winter rain and spring snowmelt for use in dry summer months.
   New dams are being studied in Washington state, California, Oregon, Idaho, Colorado, Nevada and other states, even as dams are being torn down across the country over environmental concerns — worries that will likely pose big obstacles to new dams.
   “The West and the Northwest are increasing in population growth like never before,” said John Redding, regional spokesman for the U.S. Bureau of Reclamation in Boise. “How do you quench the thirst of the hungry masses?”
   There are lots of ideas for increasing water supplies in the West. They include conservation, storage of water in natural underground aquifers, pipelines to carry water from the mountains, desalination plants to make drinking water from the ocean, small dams to serve local areas.
   Most of those ideas are much more popular than big new dams.
   In Washington state, Democratic Gov. Christine Gregoire put together a coalition of business, government and environmental groups to create the Columbia River Management Plan, which calls for spending $200 million to study various proposals to find more water for arid eastern Washington.
   Jay Manning, director of the Washington state Department of Ecology, believes that massive new dams on the main stems of rivers are unlikely. But it is quite possible that tributaries will be dammed, and reservoirs pumped full of river water.
   Action is inevitable
   “It is inevitable we will take steps to increase water supply,” Manning said. “Storage is part of that solution.”
   Demand for water from growing cities, industry, agriculture and struggling fish runs is already high. Increasing the pressure are fears that climate change will cause rain instead of snow to fall in winter, reducing the slow-melting snowpack that provides water in dry summer months.
   Gregoire’s plan drew the support of many environmentalists by including many ideas they prefer, including conservation measures and metering more uses of water.
   But the state is also studying dams, drawing opposition from some environmentalists, particularly a group called the Center for Environmental Law and Policy.
   “Our water future doesn’t lies with new dams,” said Dr. John Osborn, a Spokane physician and chairman of the Sierra Club chapter in Spokane. “It’s water conservation.”
   Osborn contends dam boosters have run a well-orchestrated, under-the-table campaign to push for new dams for the benefit of business, underplaying the costs and environmental destruction and ignoring the benefits of improving water conservation programs.
   But other environmental groups have signed on to the state’s bill, although they’re leery of the dams. A big reason is that one-third of any new water would be dedicated to survival of endangered salmon.
   “What we’re trying to do is make sure that before going down that path, and instead of going down that path, we understand what alternatives there are in conservation and water markets and aquifer storage,” said Michael Garrity, of the Seattle office of American Rivers.
   On the Columbia
   In Washington, the water crisis is centered on the Columbia River basin and the adjacent Yakima River Basin — which produce a bounty of crops, including apples, cherries, hops for beer and wine grapes. Groundwater wells in the region are being emptied to sustain millions of acres of irrigated agriculture, prompting ongoing studies of new dams.
   A major barrier to new dams is costs, which run in the billions, Manning said. It’s unclear how much the federal government would be willing to pay.
   A recent study of the Black Rock dam proposal in the Yakima River basin concludes the 600-foot-tall dam would cost $6.7 billion to build and operate, but would return just 16 cents for every dollar spent to build and operate.
   The explosive growth of the West in recent decades is in part a product of an earlier binge in dam construction that provided plentiful water and cheap electricity.
   The U.S. Bureau of Reclamation built more than 472 dams to capture, store and deliver water, including Shasta Dam in California and Grand Coulee Dam in Washington.
   The construction of Glen Canyon Dam on the Arizona-Utah border, dedicated in 1966, galvanized the rising environmental movement because the resulting creation of Lake Powell inundated a huge swath of scenic land. The uproar essentially ended the era of giant dams.
   But the population of the Western states grew nearly 20 percent in the 1990s, to more than 64 million, and continues to swell even as climate change poses new threats to the water supply.
   This month, researchers at San Diego’s Scripps Institution of Oceanography said climate change and a growing demand for Colorado River water could drain Lake Mead and Lake Powell — two of the nation’s largest manmade reservoirs — within 13 years. Critics called the study absurd, but both lakes have been hit hard by a regional drought and are half full. The Colorado River provides water for about 27 million people in seven states.
   At the same time new dams are being studied, there are efforts to remove old dams.
   In Oregon, a deal has been proposed that would remove four dams on the Klamath River to restore struggling salmon runs. Fish advocates have been using similar arguments for years in their bid to remove four dams on the Snake River in eastern Washington. The dams generate electricity and allow cargo barges to move from hundreds of miles upriver.