City of Fairmont plans for the future of curly-leaf pondweed management with MSU-Mankato

FAIRMONT, Minn. (KEYC) - Premier Lake Harvesting is finishing up its first year of combining curly-leaf pondweed on Fairmont’s Chain of Lakes, and the city says it is now working with Minnesota State University-Mankato to help plan management going into the future.

The city says curly-leaf pondweed first spread to its five lakes in the early 1990s, and it has gone through cycles of activity and dormancy over the past several decades.

In the past few years, the weed has become active again, growing in depths of up to 15 feet, crowding out native plants, catching on oars and boat propellers, and hindering fishermen at the shoreline.

As the city began brainstorming ways to tackle the issue two years ago, it was referred to Dr. Ryan Wersal, an associate professor at MSU-Mankato, who was documenting local lake plants for the Martin County Soil and Water Conservation District.

The city has currently been working on plans to manage the curly-leaf pond weed in the spring and early summer before it dies and releases buds, or turions, to reproduce.

As part of the plan, Wersal, three of his graduate students, and four undergraduate students have been mapping out where the weed is found in the lake and how heavily it is concentrated as part of an ongoing study.

The study’s first year has mapped out 275 acres of curly leaf pondweed across the five lakes.

Wersal said the goal is to create a baseline over the next two to three years to help the city develop a plan to manage the invasive weed for decades to come.

The study will also be monitoring phosphorous that has been released into the lake when the weed dies, and the algae blooms that grow because of it, to see if removal efforts can also clean up the lake in other ways.

“As our data comes in this year, as our data comes in in future years, hopefully we can get together as a group, as a committee and as a partnership, hopefully we can make tweaks to that plan as we go,” Wersal said.

Wersal said one of his graduate students, Luke Thaemert, will also be releasing a paper once the study concludes documenting their initial findings.

Hannah Neusch, the city’s water resources coordinator, says she is optimistic about how much pondweed the city has been able to clean up in this first year, but she said it is unlikely that the city will be able to completely eliminate it in the near future.

“It’s an invasive species, we can expect it to be here for some time, but what we can do is we can work with entities like the university that tell us where it is so we can manage it,” Neusch said.

Neusch said after this first year of pondweed management, there has already been a noticeable reduction in the sites the city was permitted to clear.

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