Invasive weed patch bigger than expected

The Flathead County Weed Department reports that the Eurasian watermilfoil infestation recently discovered in Beaver Lake is worse than expected.

According to weed department superintendent Jed Fisher, a diver sent to remove the plants near the boat launch on Oct. 31 discovered the weed patch was more than 10 times larger than expected.

When initially discovered in mid-October, aquatic invasive species experts had estimated the infestation to be about 12 feet by 12 feet. But the diver estimated the plants were covering a patch of lake bottom measuring 40 feet by 50 feet.

Watermilfoil typically becomes brittle in the fall and can spread when small pieces break off and float away. Workers on Oct. 31 placed barrier nets on top of the plants to prevent the watermilfoil from spreading. They also removed about 50 pounds of the weed and set it out to dry in hopes of killing it.

Crews returned on Nov. 1 to be sure the barriers remained in place and to look for any pieces of watermilfoil that might have escaped.

The size of the weed patch may force the weed department to leave barriers in over winter and monitor the situation until more removal work can be done in the spring. If that doesn't work, then crews will consider using herbicides to kill the plants.