INCHELIUM, Wash. – The beaver huffed indignantly as Rick Desautel prodded it into a wire cage. The night before, it had followed its nose to a musky scent along the shoreline of North Twin Lake on the Colville Reservation and ended up in Desautel’s trap. Two hundred years ago, trappers would have shipped the beaver’s glossy pelt to Europe to meet an insatiable demand for beaverskin hats. But Desautel, an animal control officer for the Confederated Tribes of the Colville Reservation, had other plans. The beaver and four others were released into a creek in the San Poil watershed, where their dam-building skills will help hold back water and restore wetlands trampled by cattle. Once trapped to near extinction, beavers are on the rebound. As populations increase, North America’s largest rodents are gaining scientists’ respect. Ponds and wetlands created by beaver dams provide rich habitat for other wildlife. And in the parched West, beaver dams could help mitigate the impact of climate change’s hotter, drier summers by providing natural water storage. On the arid Colville Reservation, every stream that flows year-round has 30 to 40 beaver dams in its headwaters. “They’re keystone animals,” said Desautel, who has observed and trapped beavers for more than 30 years. “They’re the only animal in the wild kingdom that changes their environment so dramatically.” The idea of using beaver dams for water storage intrigues policymakers. Earlier this year, The Lands Council of Spokane received a $30,000 grant from the Washington Department of Ecology to study the concept. Eastern Washington has about 50,000 beavers – a fraction of the estimated 2 million to 5 million that once inhabited the state’s eastern watersheds, said Mike Petersen, executive director of The Lands Council. Through its research, council staff has identified 10,000 to 15,000 miles of creeks and streams where beaver populations could be re-established. “We’re building a tool kit on beaver reintroduction,” Petersen said. “They’re a creature that used to be so abundant in the West.” The council’s staff is monitoring 50 existing beaver dams. As part of its research, the council will estimate potential water storage from beaver dams in acre-feet. “The objectives of the study are serious,” said Guy Gregory, a senior hydrologist for the Ecology Department. “While one little beaver dam isn’t much, a lot of dams could make a difference.…We want to know if we could store water with beaver dams, and how much it would cost. We’re looking for quantifiable numbers and reliable estimates.” The grant is funded through the Columbia River Project, a 2006 endeavor by the Washington Legislature to promote water storage in the Columbia Basin. Low summer flows already create conflicts among salmon advocates, irrigators, dam operators and municipal water users. Scientists anticipate more water conflicts in the future. Snowpacks across the Northwest are projected to decrease by 30 percent after 2020 and 40 percent after 2040, according to the University of Washington’s Climate Impacts Group. As temperatures rise, more precipitation will fall as rain, reducing snow accumulations that act as natural reservoirs. “We’re looking at water storage facilities that we’d fill up in the winter and drain in the summertime,” Gregory said. One of the early proposals was the Hawk Creek Reservoir, a $10 billion concrete reservoir planned near Lake Roosevelt. Although the project was later deemed impractical, it triggered Petersen’s interest in beavers. He hopes to demonstrate that the enterprising rodents can do the same work for less money, with better environmental payback. “Getting beavers into streams will cost something,” said Petersen, noting that farmers would have to be paid for flooded fields. “But it’s not going to cost $10 billion.” Lixing Sun, a beaver expert and Central Washington University professor, said beaver dams’ ability to store water is well documented. After catastrophic flooding on the Mississippi and Missouri rivers in 1992, researchers studied how beavers’ decline had diminished the watersheds’ holding capacity. Before the fur trade hit its peak in the 1800s, up to 40 million beavers lived in the Mississippi watershed. “I have always been amazed that they are so powerful ecologically,” said Sun, co-author of “The Beaver: Natural History of a Wetlands Engineer.” During the 13 years that he’s been in Ellensburg, Sun said he’s watched beavers transform 40 acres of deserted farmland on Umtamun Creek into a lush area. “That small creek has 150 beaver dams,” he said. But not everyone embraces beavers. When beavers moved into a 150-acre marsh south of Liberty Lake several years ago, their dams flooded a nearby trail. Irritated residents tore out the dams and shot the beavers. Eventually, the trail was rebuilt on higher ground. “The beavers helped re-establish the natural functions of the wetlands by damming the stream and allowing sediment to drop out of the water,” said BiJay Adams, Liberty Lake Sewer and Water District’s lake protection manager. As a result, the water flowing into the lake was cleaner. The dams also kept water levels in the lake higher during summer, said Adams, who was part of outreach efforts to help local residents understand the beavers’ beneficial role. Today, six beaver dams are visible in the marsh. But the dams again are starting to threaten trails, Adams said. On the Colville Reservation, many of the beavers used to restock watersheds were deemed nuisances by landowners. They had plugged up culverts, or their dams flooded roads. Beaver relocation began in earnest about five years ago, as the tribes’ fisheries managers learned more about beavers’ role in enhancing salmon and steelhead habitat, said Sheri Sears, resident fish division manager for the tribes. “You know the saying ‘Busy as beavers’? There’s a reason for that. They’re industrious creatures, and they can really make a difference in the retention of water in a watershed,” Sears said. Historic trapping depleted beaver stocks on the 1.4 million-acre reservation. During the 1800s, about 1,000 beaver skins moved through Fort Colville each year. High prices for pelts kept the reservation’s trapping tradition strong through the 1950s. Live trapping was a switch for Desautel, the tribes’ animal control officer, who used to earn $25 for each beaver pelt he tanned. But through his trapping experience, he’d developed a healthy respect for beavers. As a young man, he braved leeches to swim into dams, exploring the chambers inside the mud-and-stick structures. Desautel also knew how to attract beavers to traps with scent mounds. The mounds – a dirt patty squirted with beaver musk – act as territorial markers, bringing beavers to the shoreline to check out who’s in their territory. His job now is to plant the animals on the reservations. “Now, I’m the Johnny Appleseed of beavers,” he said.