New signs explain benefits of floating islands, stormwater pond

WORTHINGTON -- Thanks to funding from the E.O. Olson Trust, signs were installed earlier this week in Olson Park -- and south of the Minnesota West ball fields along Crailsheim Drive -- to help educate the public about water quality benefits.

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Okabena-Ocheda Watershed District Administrator Dan Livdahl stands next to the sign erected earlier this week to educate the public on the floating islands located in Worthington’s Sunset Bay. One of the six islands can be seen directly to the left of the sign in this photo. Julie Buntjer/Daily Globe

WORTHINGTON - Thanks to funding from the E.O. Olson Trust, signs were installed earlier this week in Olson Park - and south of the Minnesota West ball fields along Crailsheim Drive - to help educate the public about water quality benefits.

The sign south of the ball fields explains how the E.O. Olson Regional Stormwater Pond on the Minnesota West Community and Technical College campus is working to settle out solids and nutrients from urban and agricultural runoff, while the sign located along the bicycle path in Olson Park explains how floating biohavens (islands) located in Sunset Bay are filtering nutrients from the water and providing habitat for fish.
The E.O. Olson Trust gave the Okabena-Ocheda Watershed District $1,000 to create and install the two signs, which were made by Harvey’s Signs of Worthington and installed Monday.

The watershed district currently monitors 16 floating islands. Ten were installed in the E.O. Olson Regional Stormwater Pond during the past three years, and the remaining six were installed last spring in Sunset Bay.
While there were some initial problems with the islands anchored in Sunset Bay earlier this spring, the replanting of sedges, grasses and forbs into the biohavens - along with additional weights to sink the biohavens deeper into the water - have led to now-thriving islands.
“It’s kind of interesting to compare the plants (on the floating islands) in the college pond to the plants in Sunset Bay,” said OOWD Administrator Dan Livdahl. “The plants in Sunset Bay are really thriving. There are more nutrients in Sunset Bay, so the plants are super green and growing really fast.”
Meanwhile, the three-year-old regional stormwater pond doesn’t have such a build-up of nutrients in the water.
“Our big rain events haven’t been big enough to get a lot of ag land runoff,” he said. “We’re getting a lot of runoff from the college (property), but there are fewer nutrients in it.”
Still, Livdahl said the plants on the floating islands in the stormwater pond are thriving as well.
“Common sense tells us they’re using the nutrients we’re trying to remove,” he added.
Island investment
Livdahl said the watershed district has money in its budget for 2016 to invest in additional floating islands. Whether that means purchasing more biohavens or trying to build their own - or a combination of the two - has yet to be decided. Two of the islands on the stormwater pond were made by the watershed district and, thus far, seem to be working.
“The real test is how they survive the winter … and whether they continue to float,” Livdahl said, adding that marine foam was used for the base of the homemade biohavens.
Overall, the watershed district is pleased with the floating island concept in improving water quality.
“I think we will put floating islands in annually as long as we can afford to do it,” Livdahl said. “They’re one of the few practices you can install that removes nutrients after they get into the lake or pond. Most of our other practices are focused on keeping the dirty water out of the lake in the first place.”
The islands and plants aren’t cheap, so the watershed district has turned to partners for contributions. Of the six floating islands in Sunset Bay, two were funded by the OOWD, two by the E.O. Olson Trust and two by the Lake Okabena Improvement Association. The approaching winter will be the first test for the islands which, while sheltered by the west shoreline, will endure greater wind and wave action than the 10 islands in the stormwater pond.
“Sunset Bay is a more exposed environment - there’s more chance of ice action,” Livdahl said.
He said he’s also concerned about the islands being a hazard. Little recreation happens on Sunset Bay during the summer, but snowmobiles have been known to travel across the icy surface during the winter.
The floating islands were one of several items discussed during the Okabena-Ocheda Watershed District board of managers meeting Tuesday. The meeting began with the adoption of a $190,000 watershed budget for 2016 along with certification of the levy.
In other action, the board:

  • Approved a request from Joel Olson for cost-share funds to seed 50 acres into cover crops this fall. The aerial seeding will be done in standing soybeans, and Olson plans to graze cattle on the cover crops over the winter if there is sufficient growth and nutrient value in the crop. The watershed district authorized 75 percent cost-share, up to $1,256.25.
  • Approved the use of a new drainage/wetland notification form created by the Nobles Soil and Water Conservation District. The forms will be shared with watershed districts when farmers plan to install drainage or wetland projects.
  • Discussed the watershed district’s property along Minnesota 60 south of Buss Field. The soybean crop planted this year does not look harvestable. It was mentioned the soybeans could remain in place and act as a cover crop with the additional covers planned to be seeded this fall.
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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