SPOKANE, Wash. — The Western states' era of massive dam construction — which tamed rivers, swallowed towns and created irrigated agriculture, cheap hydropower and environmental problems — effectively ended in 1966 with the completion of Glen Canyon Dam on the Arizona-Utah border.

But the region's booming population and growing fears about climate change have governments once again studying construction of dams to capture more winter rain and spring snowmelt for use in dry summer months.

"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?"

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.

Ironically, consideration of new dams comes even as older ones are being torn down across the country because of environmental concerns — worries that will likely pose big obstacles to new construction. In Oregon, a deal has been struck to remove four dams on the Klamath River to restore struggling salmon runs.

There are lots of other ideas for increasing water supplies in the West. They include conservation, storing 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.

Washington's 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 for finding more water for arid eastern Washington.

Jay Manning, director of the Washington state Department of Ecology, believes that huge new dams on the main stems of rivers are unlikely. But it is quite possible that tributaries will be dammed.

"It is inevitable we will take steps to increase water supply," Manning said. "Storage is part of that solution."

With demand for water already high, pressure is being increased by fears that climate change will produce rain instead of snow 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.