DNR, EOLIC to combat curlyleaf

Tuesday, April 4, 2017
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For an area that prides itself on blue water, the Iowa Great Lakes have been seeing a fair share of green.

Curlyleaf pondweed threatens to jam boat lifts, entangle propellers and plug motors once again in 2017. The East Okoboji Lakes Improvement Corporation, the city of Orleans and the Iowa Department of Natural Resources are partnering to reduce that difficulty by cutting paths through dense patches of the weed on East Lake Okoboji.

“This will be our third year trying to address the problem,” Orleans Mayor and EOLIC president Bill Maas said.

DNR fisheries biologist Mike Hawkins said the partnership plans to address areas near the Iowa Highway 9 bridge and the Narrows.

“Curlyleaf pondweed is not just isolated to these areas in Okoboji,” Hawkins said. “We have it throughout the chain (of lakes).”

Hawkins said the weed has been in the lakes since approximately the 1950s but hadn’t been much of a nuisance until the last three years or so.

“The last two years have been pretty severe as far as the level of curlyleaf pondweed, compared to other areas of the Iowa Great Lakes,” he said, noting large growths were also identified in Big Spirit Lake. “It was in deeper water, so it didn’t cause the navigational difficulties we’ve had on East Okoboji.”

Boating problems related to the thick patches of weeds spurred some in the EOLIC to call for action. The prevalence of the weed has caused some boaters to unwittingly burnout their motors, according to Maas. He was particularly concerned the same could happen to an emergency craft, like a region's fire and rescue boats.

The curlyleaf pondweed has thrived recently because of unseasonably warm temperatures. Ice conditions and water clarity have allowed sunlight to shine deep into the lake and nourish curlyleaf pondweed during the winter. The weed actually begins its germination cycle under the ice. Minnesota, having similar weather, has also reported recent growth spurts of the weed, according to Hawkins.

“It looks like this amplified growth is really environmentally-driven,” Hawkins said. “Late ice ups, short ice duration and thin ice really allow this plant to get going during the winter. It utilizes that cool water period. So, it gets a leg up on the native aquatic plants. By that first week in May, we’re seeing it grow all the way to the surface.”

Maas agreed, saying he has seen ecological changes to the lake in his time.

“I can remember in the '60s, the top 6 inches of the water would be filled with this green algae,” Maas said. “You got down below that and it was clear water but you couldn’t see anything because it filtered out all the light. So you had very few weeds growing. It’s just a totally different ecological situation now.”

The EOLIC has reached an agreement with Underwater Solutions, a local business, to mechanically cut and remove some of the curlyleaf pondweed from East Okoboji.

“The thought here is to be able to create some lanes so people can boat out to open water,” Hawkins said.

Maas estimated the lanes may be 20-25 feet wide. This will allow navigation but some lanes will be too close to shore for boats to safely reach planing speed. Maas said Underwater Solutions has invested in a new piece of machinery which not only cuts the weeds but harvests and removes them as well.

While Hawkins admitted the navigational downside of the weed in the lakes, he noted it has brought some benefits as well.

“When you have an invasive species like curlyleaf pondweed, we’re obviously dealing with the downside,” Hawkins said. “The upside is that we do see improvements in water quality because of the plant. It is utilizing nutrients that would go to our algae bloom.”

Maas said this makes the issue of “clean” water a murky subject.

“What does it mean to keep the lake clean? You get into some moral obligations there because everybody likes clean water,” Maas said. “With clean water, you get more weeds. Then you say, 'The weeds are a mess. Clean those up.' Where do you stop? That’s the problem because the weeds actually contribute to making the water cleaner.”

Water clarity is at its highest in recent history, according to Hawkins. He attributed the clarity to the weed’s ability to dampen wind and wave action, which would stir up sediment on the lake bottom. In addition, the curlyleaf pondweed provides habitat for some species of wildlife. Hawkins said the department has seen a significant increase in pan fish population recently, which may be linked to the weed.

Hawkins said these benefits will not likely be diminished by the EOLIC’s plan.

“We probably, financially, cannot control enough of it to impact the positive,” he said.

Hawkins estimated 6,000 acres of water have been affected by curlyleaf pondweed but said the contract with Underwater Solutions will remove approximately 12-20 acres of the weed.

Though low-dose herbicide is an option, there has been apprehension about use in the Iowa Great Lakes.

“Herbicide is something we do as a department on a number of other lake systems, but, in Iowa, that has not happened and been performed on a drinking water system,” Hawkins said. “Until we can reach a consensus in the community, we don’t want to go down that path. We want to work with local people on that. So that leaves us mechanical.”

Maas echoed Hawkins’ words and added the chemical would need to be reapplied each year.

“To put chemicals in the water would require right at $200,000 per year, to knock the weeds down completely,” Maas said. “Next year, they come right back. It’s kind of like Canadian thistle, It’s a weed and grows like a weed.”

In addition, Maas said some false information regarding the use of the chemical reached the governor’s office resulting in a ban on permits for the use of certain aquatic herbicides. The EOLIC began to further examine cutting the weeds.

“It was going to be cost prohibitive for a group our size to be able to handle the project alone,” Maas said. “So we started seeking allies.”

Grant funding from the DNR was available for the project, but Maas explained the funding could only be issued to public entities and governing bodies.

“Logically, you’d go to a city that’s bordering on the problem,” Maas said. “‘Of course, being mayor of Orleans, I had the ties to work directly with my city council. They said, ‘Sure, we’d like to help, especially if it isn’t going to cost us anything.’ So, it isn’t costing the city of Orleans taxpayers anything.”

Maas said the EOLIC will be paying approximately $5,300 through the city of Orleans to fund the project. He said the group has already raised the amount through dues and private donations. Likewise, the DNR has set aside funds.

“The state of Iowa has contracted with the city of Orleans,” Hawkins said. “We’ll cost share 75 percent. The department has committed up to $16,000 as long as the community can match 25 percent.”

He said the $16,000 will be funded through the Marine Fuel Tax Fund. Hawkins noted the lanes cut into the curlyleaf pondweed will need continued maintenance if they are to remain clear.

“The plant grows very aggressively,” Hawkins said. “I’d like to say it’s going to go away but it all depends on how severe our winters are and how quickly we ice up in the fall.”

Maas was unsure if the EOLIC will have the funds to tackle the curlyleaf pondweed again next year. However, he stressed that the weed is not just a East Lake Okoboji problem or a “lakeshore people” problem. He noted the Iowa Great Lakes are used by many people from outside the county. He said, in some ways, the residents of Dickinson County have been saddled with a task that is a state issue.

“You can’t assess all the people of Dickinson County because those are sovereign waters,” Maas said. “They belong to the state of Iowa. Every person that’s a resident of the state of Iowa has a vested interest in this lake because they own part of it.”

Hawkins and Maas estimated the project would begin later this month or in early May. Maas hopes if the project is successful, local support will increase and the weed will be kept at bay.

“We’re got a program going that we think will do a lot of good for everybody but we don’t know,” Maas said. “We won’t know until we see the results at the end of this year.”

Maas said the best way for those interested to become involved is to join any of the Lakes area protection agencies. Information for many of the agencies can be found online at: http://iagreatlakes.com/preserving-the-l....

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