Beaver Lake quarantined for milfoil

The Montana Department of Agriculture on July 18 ordered a temporary quarantine of Beaver Lake, north of Whitefish, closing the lake to all watercraft but not anglers or swimmers.

The action came after locals informed Ag Department weed coordinator Dave Burch that Eurasian watermilfoil, discovered near the boat ramp at the lake last fall, had grown so much this past spring that it was tall enough to get caught on boats.

Beaver Lake is the only known water body in the Flathead River basin infested by Eurasian watermilfoil. Barrier mats had been placed on the 25-by-25-foot patch of noxious weeds to limit growth and control further expansion in the lake.

A diver-operated suction dredge went to work last week to remove the weeds. Burch said a barricade would be installed at the boat ramp to stop people from launching watercraft during the quarantine. He expected the quarantine to be lifted in about a week.

Divers inspected the lake bottom around the infestation four times this spring, including twice two weeks ago. They reported that the barrier mats placed on top of the weeds had shifted, and weeds were sprouting in the gaps between the mats and around the edges.

Montana Fish, Wildlife and Parks had recently completed a final decision notice on a plan to manage and if possible eradicate the Eurasian watermilfoil. A draft environmental assessment for the proposed plan was prepared by FWP, Montana Department of Agriculture, Montana Department of Natural Resources and Conservation, Flathead County, Flathead Basin Commission, Whitefish Lake Institute and others.

The plan calls for using barrier mats, mechanical removal, herbicide treatments or a combination of these methods to eradicate the noxious weed. There is also talk about installing a barrier at the lake’s outlet to prevent the spread of the noxious weed.

The environmental assessment was released for a 21-day comment period on June 13. FWP received three letters from private individuals all in support of the proposed plan. A copy of the decision notice is available online at www.fwp.mt.gov under “public notices.”