Three northern lakes experiencing a reduction in aquatic invasive plants

Three Kosciusko County lakes are experiencing a reduction in invasive Eurasian watermilfoil this spring.

Center, Big Chapman and Webster lakes have had recurring problems with Eurasian watermilfoil (EWM) in past years. EWM is present in most Indiana lakes. It often grows so densely that it creates a nuisance for boating and fishing. It also can outcompete more desirable native aquatic plant species.

In 2015, EWM occupied 38 percent of the surface area at Center Lake. This spring, EWM occupies only 4 percent of surface area.

Biologists have observed similar declines at Webster and Big Chapman lakes.

All three lakes have received selective aquatic herbicide treatments the last few seasons designed to control EWM. Funding for treatments was provided by the Indiana Department of Natural Resources Lake and River Enhancement Program (LARE) in combination with the local lake associations.

DNR biologists believe the treatments explain the reductions, at least partially.

“We have observed what we would consider more typical plant growth at other northern Indiana lakes this season,” LARE aquatic biologist Rod Edgell said. “So, our observations at Big Chapman, Center and Webster lead us to believe that the treatments are helping.”

Visual inspections this spring also indicated good coverage of native plants, which is the ultimate goal of aquatic invasive plant control.

EWM can grow later in the season, so biologists are continuing to monitor the lakes All three lakes received EWM treatments in May. Vegetation surveys are planned for July and August to fully evaluate the treatments.

“Aquatic herbicide treatments often receive too much criticism and at times too much credit,” Edgell said. “Mother nature plays a larger role than most give her credit, but we will continue assisting when we can.”

For more information on aquatic invasive species and how to prevent their spread, visit

For more information on EWM and the LARE Program, call Edgell at (260) 244-6805.

To view all DNR news releases, please see

Contact Information:
Name: Rod Edgell
Phone: (260) 244-6805