Eurasian Milfoil Eradication

Three Lakes is working to eliminate Eurasian watermilfoil from our rivers and lakes.

Eurasian watermilfoil (EWM) is a nuisance invasive aquatic plant that can reduce the quality of the aquatic environment through excessive growth.  This causes native plants to be replaced, reduces plant diversity, adversely impacts fish habitat, and can interfere with boating and swimming activities due to the effects of large weed beds.  The Three Lakes Association, in collaboration with HelenaTownship, Torch Lake Protection Alliance, and Butch’s Marina, contracted with Aquacleaner to have EWM that had been discovered at Butch’s, at the AldenHarbor, and in TorchLake in the embayment between Stony and Lone Tree Points, hand-removed in the summer of 2011.

Despite the divers’ best efforts, the EWM at those locations re-emerged in 2012.  In the summer of 2013, TLA, in collaboration with Helena Township and Butch’s Marina, engaged PLM Lake and Land Management Corp. to treat the marina and the harbor with Renovate OTF pelleted herbicide.  Although it required two applications, the herbicide treatment was effective in killing off the EWM.  Now TLA will be monitoring these sites for any re-emergence, something that is fairly likely as the EWM can regrow from not-quite-dead-yet roots in the lake bed.

We plan to use mechanical control rather than chemical to deal with any EWM that shows up.  Thanks to the Dole Family Foundation, we have funds available to purchase benthic light barriers which are known to be highly effective in discouraging the growth of the EWM.  We are conferring with our local MDEQ personnel to develop the necessary permits for the benthic barriers.

These articles, Efficacy of Benthic Barriers as a Control Measure for Eurasian Watermilfoil, and Benthic barriers, provide more detail on Benthic Light Barriers.

If you think Eurasian Watermilfoil is growing near you please contact us.