Islands on the rise: OOWD to buy, build more floating biohavens

WORTHINGTON -- More floating islands will be added to Sunset Bay and the E.O. Olson Regional Stormwater pond this spring and summer after the Okabena-Ocheda Board of Managers approved the purchase of two islands, the materials to make two islands...

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Vegetation on this floating island is protected with the use of fencing to prevent geese from nesting on the biohaven. Submitted photo

WORTHINGTON - More floating islands will be added to Sunset Bay and the E.O. Olson Regional Stormwater pond this spring and summer after the Okabena-Ocheda Board of Managers approved the purchase of two islands, the materials to make two islands and the plants for all four of them during its meeting Tuesday.

The watershed district began experimenting with floating islands in 2013, purchasing the biohavens from Minnesota-based Midwest Floating Islands. The islands are promoted as a way to remove nutrients from water bodies and provide food and habitat for aquatic life.

While OOWD Administrator Dan Livdahl said the district would need to have considerably more islands on both Sunset Bay and the stormwater pond to show a measurable difference in water quality, he is seeing some benefits to the islands.
“I think the plants are using nutrients - they’re creating a lot of root mass underneath that creates a biofilm and food for aquatic creatures,” he said. “It’s one of the few things we can do in the lake that has multiple benefits - it removes nutrients, creates fish habitat, wildlife habitat and some diversity. They should be attractive, too.”
Livdahl said the plants growing on the floating islands during the spring, summer and fall do quite well.
“The conditions in Sunset Bay seem to be much better for plant growth, which means we have more pollution in the water,” Livdahl said.
Meanwhile, vegetation on the islands in the stormwater pond appears to be stunted during the growing season - something he said may be due to the reduced level of nutrients in the water.
“We had the best plant response when we had the geese take over the islands and deposit manure all over,” he said. “I think that shows the islands needed more nutrients than the pond was providing them.
“We would expect that as the pond collects more soil and nutrients over time, that pond will become more fertile.”
The watershed district has eight floating islands on the stormwater pond, and thanks to a partnership with the Lake Okabena Improvement Association, installed six floating islands in Sunset Bay last spring.
Livdahl said there have been some hurdles with the islands, particularly in keeping them in place. The floating biohavens are anchored with cement blocks and stainless steel anchor chains and are weighted down with field rocks so plant roots have access to the water and nutrients in the bay and pond.
“We put the recommended anchor weight on each island, but whoever made those recommendations wasn’t figuring the prairie wind out here,” Livdahl said, adding that six of the islands in the stormwater pond broke anchors last fall on a day when sustained winds of 40 to 50 mph proved to be too much.
There were also some problems with geese nesting on the islands and destroying the vegetation, although Livdahl said after they established fencing, the vegetation came back and did really well with the goose droppings providing additional nutrients.
Livdahl said the plan is to launch the two new purchased islands in mid-May, when students in Jeff Rogers’ class at Minnesota West Community & Technical College can help plant the plugs and launch the islands in the bay. The two islands the watershed plans to make will be launched this summer with the help of interns shared with the Heron Lake watershed District.
In other action, the board:

  • Authorized a $5,000 contribution toward Nobles County Soil and Water Conservation District’s purchase of a 15-foot drill. The Kanaranzi-Little Rock Watershed District will also be asked to participate, along with Nobles County Pheasants Forever. The drill is used by the OOWD to seed native prairie. The SWCD currently owns a 7-foot drill, which will still be available.
  • Approved sharing a couple of interns again with the Heron Lake Watershed District, at a cost of up to $2,000.
  • Discussed use of social media as a tool to present information from the watershed district and gather public input. Manager Jay Milbrandt volunteered to work with Livdahl on the idea.
  • Agreed to sign a letter in support of the Conservation Reserve Enhancement Program, which will be shared with U.S. Department of Agriculture Secretary Tom Vilsack.
  • Discussed, but took no action on, future management of the St. John’s property, which is located along U.S. 59/Minnesota 60, southwest of Nobles Street. There is an option to rent the land to farmers, or to develop perennial cover on the property. A third option may to develop a pollinator site on the land.
  • Spoke briefly about the Lake Ocheda Enhancement project and the need to schedule a meeting with landowners who own property around the lake to gather input before decisions are made. The plan is to schedule a meeting with landowners yet this month.
  • Was alerted to a potential partnership with Nobles County Pheasants Forever to purchase a 30-acre tract along the Herlein-Boote Slough. Scott Rall, president of the local PF chapter, said the group plans to pursue funding from the Lessard-Sams Outdoor Heritage Council first, and if they are successful in getting a grant, they will not need to partner with the watershed district.
  • Approved the watershed district’s 2015 annual report.
  • Received the 2016 annual plan and budget. Managers were asked to read through the document and be ready to act on the report at the April 5 meeting.
Related Topics: WATERSHED
Julie Buntjer became editor of The Globe in July 2021, after working as a beat reporter at the Worthington newspaper since December 2003. She has a bachelor's degree in agriculture journalism from South Dakota State University.
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