The work of beavers has put an earthen dam at risk of failure off Montana Highway 2 between Butte and Whitehall.
The U.S. Forest Service is in the process of drawing down the water at the dam to prevent dam failure. Beavers plugged up a pipe that allows water to flow past the dam and on downstream in North Fork Creek. The area is off Radar Creek Road.
Forest Road #9319 is also closed.
The Beaverhead-Deerlodge National Forest closed Toll Mountain campground, which is just downstream of the dam, Friday to ensure the public’s safety.
Dave Sabo, Beaverhead-Deerlodge National Forest Butte district ranger, said the problem originally occurred in the spring. The Forest Service got the water down to a manageable level by early June, but the beavers got to work in the meantime.
Sabo said there are seven homes in the area. The homeowners have all been notified, Sabo said.
He said the dam also acts as a road to a few of the homes. The Forest Service believes the dam was built in the 1800s to serve a small saw mill.
Erin Ryan, Beaverhead-Deerlodge National Forest hydrologist, said that when the water is at its highest, the dam is about 7 feet high.
Sabo said the homeowners find the 2-acre pond the beavers built by plugging the pipe more aesthetically pleasing than the swampy area the draw-down creates.
He said the Forest Service cannot take on the liability to allow a pond to back up behind the earthen dam. But he said the homeowners are discussing trying to have the dam engineered themselves so they can get their lake back.