Aquatic invasives — the battle continues

Angie Hong - Washington Conservation District

A long time ago in a galaxy far, far away, the aquatic invaders reign. Having decimated the native plant and mussel populations, Eurasian watermilfoil and zebra mussels now deploy merciless legions to seize control of lakes across Minnesota. Only a feisty band of resistance fighters — watercraft inspectors, resource professionals and lake association members — stand against the rising tyranny, certain that the latest macrophyte surveys will restore a spark of hope to the fight.

Not so long ago, in a galaxy awfully close to home, the Minnesota legislature allocated just over $132,000 to Washington County to battle against real life aquatic invasive species (AIS) that creep steadily further into our beloved lakes and rivers each year. During the Dec. 6 Washington County Water Consortium meeting, project partners shared some of the ways that this funding was used in 2017. 

Non-native aquatic invasive species, such as zebra mussels, spiny waterfleas, Eurasian watermilfoil, faucet snails and viral hemorrahagic septicemia, currently inhabit a small percentage of lakes and rivers throughout the state. However, the vast majority of lakes and rivers in Minnesota are not yet infested.  By understanding the threat and working together, we can keep it that way.

Toward this goal, Washington County allocated approximately 50 percent of its 2017 AIS funding to conducting watercraft inspections at public boat launches in partnership with the Washington Conservation District and Comfort Lake – Forest Lake Watershed District. 

In addition, the Minnesota Department of Natural Resources conducted additional inspections through a separate funding source. Watercraft inspectors talk with boaters as they get on and off the water and visually inspect boats and trailers to make sure they are clean and dry. Because aquatic invasives are virtually impossible to eradicate once they infest a water body, preventing new infestations is the most important way to limit the economic and environmental impact of AIS in Minnesota. 

This year, Washington Conservation District and Comfort Lake – Forest Lake Watershed District conducted over 10,000 inspections and found that more than 95 percent of boaters had complied with laws requiring boats to be cleaned and drained before leaving boat launches and before entering new water bodies. Unfortunately, inspectors also found 259 boats entering or exiting with plants, mussels or mud attached, and 282 boats with drain plugs still in. Statewide, 35 new water bodies became infested by AIS in 2017. 

Though an ounce of prevention is worth a pound of cure, Washington County also distributed just over $50,000 to lake associations and watershed districts to manage existing AIS infestations. Currently, the St. Croix River and 21 lakes in Washington County are infested by Eurasian water milfoil; zebra mussels have been found in Forest Lake, White Bear Lake and the St. Croix south of Stillwater; and there is flowering rush on the shores of Forest Lake. Curly leaf pondweed and common carp are also ubiquitous throughout the region. 

In 2017, Washington County provided funding to Big Marine, Clear and Lake Demontreville/Olson lake associations to chemically treat Eurasian water milfoil; to Lake Elmo lake association to manually pull Eurasian watermilfoil; and to Comfort Lake – Forest Lake Watershed District to chemically and manually treat flowering rush in Forest Lake. The goal of these treatment efforts is to prevent the invasives from spreading further within each lake and to lessen the impacts on fishing, boating and other recreation. 

The remaining funding, approximately $14,500, was used for education, early detection monitoring and rapid response planning. Nine new Jedi were trained in the ways of the Force through the University of Minnesota’s new AIS Detectors course. Washington Conservation District staff visually monitored every public lake access in Washington County once a week from April through September and conducted intensive inspections on Big Carnelian and Square Lakes to look for potential new invasive species. The St. Croix River Association also met with marina owners along the St. Croix River and visually inspected dry-docked boats to look for attached zebra mussels. 

Next year, Washington County will have just over $136,000 available to support resistance fighters in their continued battle against aquatic invasive species. Will our brave heroes succeed? Stay tuned to find out.

Angie Hong is an educator for East Metro Water - - which includes Brown’s Creek, Carnelian Marine - St. Croix, Comfort Lake – Forest Lake, Middle St. Croix, Ramsey Washington-Metro, Rice Creek, South Washington and Valley Branch Watersheds, Cottage Grove, Dellwood, Forest Lake, Grant, Hugo, Lake Elmo, Newport, Oak Park Heights, Oakdale, Stillwater, St. Paul Park, West Lakeland, Willernie and Woodbury, Washington County and the Washington Conservation District. Contact her at 651-330-8220 x.35 or

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