Floating islands take shape at Covell Lake with new sustainability effort

Floating habitat islands now are part of Covell Lake at Terrace Park, supporting local biodiversity and waterway health.

They’re a collaboration between CNH Industrial, which acquired Sioux Falls-based Raven Industries in 2021, and the nonprofit Friends of the Big Sioux River.

The goal for CNH was to put sustainability efforts into action and offer publicly accessible educational opportunities focused on Sioux Falls’ water bodies.

Discussions began six months before installing the floating islands, which happened Friday at the park in northwest Sioux Falls, as the project was born out of a mutual commitment to sustainability.

The CNH Sioux Falls sustainability committee was highly involved, meeting with Friends of the Big Sioux River to discuss a potential partnership and explore possible project models.

Program manager Sienna Mayer and electrical design engineer John Waltz used their engineering experience to solidify a design. A budget was approved by the sustainability committee, and the building process began.

“It’s that care for the world and wanting to leave it a better place,” said Lisa McElrath, CNH communications manager. “I think it was just a natural extension and an easy fit when we made the connection with FBSR.”

The islands themselves are made of 4-inch PVC pipes glued together to form a 6-by-7-foot structure. Coco coir — a natural fiber made from the husk of coconuts — is enclosed in a burlap fabric to serve as a growing medium. Once plants start to grow on the panels, nutrients can be taken from the water as roots dangle below the surface. The panels are installed using an anchor to the lake bottom.

“We went through a few different kind of design options as far as how to make it float and how to actually have structure to it,” Waltz said. “We considered things like dock floats, pool noodles, anything that floats really.”

The islands are not all the same. In efforts to decide which plot of plants will perform the best, the plants on each island will act as controlled variables. There will be one with just wetland plants, two with completely native prairie plants and one with a mix of both.

As the plants absorb nutrients from the water, their roots will filter out harmful pollutants. Aside from improving water quality, the islands also promise positives for surrounding wildlife. Once the flowers are in bloom, bees, butterflies and other insects will be able to use them as pollinator plots. Moving up the food chain, bird populations will see the benefits of an increasingly native habitat, and fish populations will benefit from the structure and safety underneath the panels.

“I’m hopeful that the community will see it as a tool to just help have more widespread education about these sorts of topics and how you can — even in urban environments — have positive ecosystems for our animals,” Mayer said.

While the new islands are in Covell Lake, others might be placed in the Big Sioux River in the future.

“It’s been a kind of a motivator from the beginning. Raven, too, is right on the river. People love to comment on the river, the state of the river. It’s always got kind of a bad rap,” Waltz said.

“So being able to kind of jump from that and be like, all right, let’s do something about it and try to encourage more people to actually do something about it rather than just, you know, talk about it or complain about it.”

The hope is that conversation around environment sustainability continues to have a place in the city’s future, Mayer said.

“I hope that it kind of sets us on a trajectory of not expecting it to just be like the environmental nonprofits who are playing a role in making positive change. I think that as individuals, we have a role to play. I think that companies and businesses have a role to play,” Mayer said. “This is everybody’s environment, and we should all be taking care of it.”

The public is invited to come see the islands while they’re in the lake this summer.

“That’s the big thing,” said Emily Oyos, Friends of the Big Sioux River’s education and outreach manager.

“That’s how we’re going to get education out there and get eyes on the project and get people talking about it and wondering: ‘Hey, what’s that thing that’s floating out in the middle of Covell Lake?’”