Beaver Lake boat launch to stay open despite milfoil

The Beaver Lake boat ramp is set to stay open through the spring despite a large patch of invasive Eurasian watermilfoil that was found in the vicinity last fall. The decision goes against recommendations from city officials who are concerned the plant could spread to other areas, including Whitefish Lake.

The plants were found in a 12-by-12 foot area in Beaver Lake, west of Whitefish Lake. They were found by Department of Natural Resources and Conservation workers during a field trip to the lake in October. The lake’s boat ramp was closed during efforts to contain the plant. It was reopened by winter.

Milfoil is a threat because it roots itself to the bottom of water bodies and forms dense mats at the water surface shading out native plants, clogging motors and making swimming nearly impossible.

The plant can spread rapidly because it reproduces through stem fragmentation. Pieces the size of postage stamps that have broken off the main stem can reproduce. It’s most often spread overland by boats that have not been cleaned properly.

In a letter to FWP, Whitefish Mayor John Muhlfeld said he was concerned about opening the boat ramp too soon.

“I have tracked this issue closely,” he wrote. “While the efforts of the Flathead County Weed District were valiant, the [invasive watermilfoil] at Beaver Lake was not fully eradicated as plant fragmentation occurred during treatment. Since this is a plant that propagates via fragmentation, the likelihood that some of the [invasive watermilfoil] survived to reproduce is a virtual certainty.”

He said he was sensitive to keeping public resources open, but those concerns were trumped by the consequences of the invasive plant spreading to Whitefish Lake.

He notes that Beaver Creek connects Beaver Lake with Whitefish Lake, and could serve as a transporter of disturbed mifoil.

In response to Muhlfeld’s comments, FWP Regional Supervisor James Satterfield said they were following the same protocol as other locations in the state where the Watermilfoil has been found.

FWP has roped off the infected area and has placed signs to keep boats out and to remind boaters to “inspect, clean and dry” their boats.

As the lake’s water temperature warms, biologists will monitor the site to see if the milfoil expands to other parts of the lake. A task force will produce an Environmental Assessment that will be out for public review by this spring.

The EA may propose additional measures to eradicate the plant, including chemical control as well as mechanical.