Lake Minnetonka Conservation District continuing harvesting aquatic invasive plants through August

(Photo courtesy of the Lake Minnetonka Conservation District)
A harvester on Lake Minnetonka that cuts Eurasian watermilfoil and curly-leaf pondweed.

By Paige Kieffer
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The Lake Minnetonka Conservation District is currently conducting its annual harvesting of the aquatic invasive species, Eurasian watermilfoil and curly-leaf pondweed, that was started in June and will end in mid-August.

The harvesting started June 15 and Lafayette Bay, the west side of Spring Park, Phelps Bay, the south side of Enchanted Island and Shady Island have all been complete.

Priest Bay, Smithtown Bay, Cooks Bay, Black Lake, Seton Lake and Emerald Lake is being completed this week.

For a listing of bays being harvested on Lake Minnetonka, visit lmcd.org or follow the Lake Minnetonka Conservation District on Facebook.

The invasive plants are heavily spread throughout the lake.

(Photo courtesy of the Minnesota Aquatic Invasive Species Research Center) Eurasian watermilfoil

According to the state Department of Natural Resources, Eurasian watermilfoil is a long thin plant that quickly spreads throughout lakes, crowding out native plants and creating dense mats that interfere with recreational activity.

Curly-leaf pondweed thrives in conditions normally less habitable to native plant species and clogs waterways making it difficult for aquatic recreation. It also competes with and sometimes displaces native plant life.

“The plants are really all over Lake Minnetonka,” said Vickie Schleuning, Lake Minnetonka Conservation District executive director. “We’ve been really looking at the bays and some have a lot, some a little and others a mix.”

Schleuning said that curly-leaf pondweed has heavily increased this year. She added that the worst bays for both aquatic invasive plants have been Lafayette Bay, Enchanted Island and Priest Bay.
The harvesting season starts with a lake-wide assessment of all the bays and lakes on Lake Minnetonka.

“There are different ways where we determine where we are going to harvest,” Schleuning said. “First we did the lake wide assessment for the public navigation, and then even on a daily basis, you’ll go look at the areas that are worse and then put those on the schedule. We also get feedback from residents and businesses on the lake and they’ll contact us to notify us which areas are bad.”

(Photo courtesy of the Minnesota Aquatic Invasive Species Research Center)
Curly-leaf pondweed

The conservation district has three harvesters, with two machines being used this year.

Harvesters are like an underwater lawn mower that cuts aquatic invasive plants by a few feet allowing the water to be more passable.

The plants are then picked up by a conveyor at the forward end of the machine, which can be lowered up to six feet deep to cut weeds.

A barge-like boat then picks up the plant cuttings and brings the cuttings to a off-loading site on shore. The cut plants are then used for compost on local farms.

The harvesters run every week Monday through Thursday, depending on the weather.

A few bays also treat the invasive plants with a herbicide treatment. Currently there are no lake-wide herbicide treatments but Schleuning said the conservation district is hoping to do more research on other forms of management in the future.

The conservation district rely on many local tips to make sure all the aquatic invasive plants have been cut.

“If people see any Eurasian watermilfoil or curly-leaf pondweed that may have been missed or needs another going over again, I would encourage them to contact us right away because once we’re out of that bay we might not get back there for the next round for quite a while,” Schleuning said.

She advises that residents and businesses contact the conservation district right away if they have a tip at 952-745-0789.

Follow Paige Kieffer on Facebook at facebook.com/mnsunsailor.