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Public meeting to discuss Iowa Great Lakes curlyleaf pondweed management plans

  • 9/19/2017 2:30:00 PM
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SPIRIT LAKE - Recommendations to manage the invasive curlyleaf pondweed at East Okoboji Lake and Lower Gar Lake will be presented at a public meeting at 6:30 p.m., Sept. 28, at the Sami Bedell Center for the Performing Arts on the Spirit Lake High School campus.

A team, made up of leaders from the county, local cities, lake associations, drinking water utilities, Iowa Lakeside Lab and the Iowa Department of Natural Resources (DNR) have been working together over the past few months on a plan to manage an invasive aquatic plant that has caused water access and navigation issues for many Iowa Great Lakes residents and lake users. Team members will be on hand at the meeting to answer questions and take comments on the proposed plan.

“Curlyleaf pondweed has been in our lakes since the middle of the last century, but under mild winter weather conditions it can gain a foothold growing to form dense mats impacting recreation and access,” said Mike Hawkins, Iowa DNR fisheries biologist.

Terry Wilts, with the East Okoboji Lakes Improvement Corporation, helped spearhead this effort and explains that there are no easy options to solve this problem.

“This plant impacts hundreds of acres.  As a team, we realize that we can’t treat all of it, but should prioritize our funds and efforts.“ Wilts adds, “Our team is made up of folks on each side of this complex issue. The proposed plan is a measured compromise we can all support.”

The proposed management plan includes working to at least double the number of acres harvested mechanically in 2017. To do this, a larger commercial harvesting system will be brought in on loan from the residents of Carter Lake near Council Bluffs. This harvester is not currently in use, and will give the community a chance to try out a bigger machine. Harvest should increase significantly with this bigger harvester working alongside the commercial unit used in 2017.

Treating two 10-acre test areas with an approved aquatic herbicide, Aquathol K, is another treatment option recommended by the team. The use of herbicides to control aquatic plants is common in other lakes, but has never been tried in the Iowa Great Lakes. The use of herbicides has been controversial in the Iowa Great Lakes for many reasons, but the team plans to show how it can be used safely and effectively as a part of the overall plan. The two test areas, one in the extreme northern end of East Okoboji Lake and the other in Lower Gar Lake, will be monitored to determine effectiveness.  Water samples will also be taken to confirm the herbicide doesn’t move outside the treatment area.

The team hopes to increase efforts to educate the community about treatment options and the level of control that is possible. They will work with the DNR and other agencies to increase awareness and help stop the illegal use of herbicides.  

Eric Stoll, with Milford Utilities which supplies drinking water for thousands of customers in the region states, “We can’t tolerate lakeshore residents illegally applying herbicides. Only the DNR has the authority to put these chemicals in the lake. Everyone living or vacationing in this area gets their drinking water from our lakes. Not following the law endangers that precious resource.”

Funding for the project will come from local contributions to the East Okoboji Lakes Improvement Corporation and the DNR’s Marine Fuel Tax Fund which is dedicated to improving boater access in Iowa.

The 2018 proposed management plan is available online at

Written comments can be sent by e-mail to or mailed to the Iowa DNR, 122 252nd Ave, Spirit Lake, IA 51360.

Any person attending the public meeting and has special requirements such as those related to mobility or hearing impairments should contact the DNR or ADA Coordinator at 515-725-8200, Relay Iowa TTY Service 800-735-7942, or, and advise of specific needs.