Wildlife & Nature

Award-Winning Floating Wetland Possible Remedy for Blue-Green Algae Blooms


The structure holds nearly 20 native wetland plant species. (Alexandra Ionescu/Rhode Island Collective)

Floating in a circle around a pond in Massachusetts is a mini-wetland built by six Rhode Islanders. Earlier this summer, the mostly natural creation was chosen as the winning installation in the seventh annual Art on the Trails outdoor art and poetry program.

But the freshwater wetland, built by a group of Ocean State artists, designers, and a botanist, wasn’t commissioned to win an award. It was designed to raise awareness about the importance of wetlands and show how they work. Mission accomplished.

Art juror Sarah Alexander, who chose “Below and Above: A Floating Wetland Supports Life” by the Rhode Island Collective as the best installation, said, “The amount of careful research and thoughtful response to the space, along with the combined efforts of its dedicated creators, blew me away.”

In the seven years of Art on the Trails, the Rhode Island-built floating wetland was the first entry to be more than just aesthetically pleasing. The wetland has been floating in Ice Pond in Southborough since June 11. It was created by sourcing native plants, and experiments with natural cordage. It shows how pollutants could be sucked from stressed waterbodies with a little help from human hands. A single anchor line keeps the wetland floating in a 15-foot circle, and not all over the popular skating pond.

Members of the Rhode Island Collective include Holly Ewald (visual artist), Maxwell Fertik (interdisciplinary artist), Alexandra Ionescu (ecological artist), Hope Leeson (botanist), and August Lehrecke and Matthew Muller (co-founders of an inflatable architecture studio), who led the project’s construction.

The members weren’t a roving gang of environmentalists who all knew each other prior to building an award-winning wetland. Ewald knew Ionescu and Leeson, who knew Fertik, who knew Muller and Lehrecke. They all brought different experiences and expertise that jelled well together.

“The floating wetland ecosystem creates a habitat for the more-than-human world below and above the water line through the growth of native macrophytes. Through the plants’ life cycles, they regenerate the food web, amplifying the natural processes between sunlight, water, and microorganisms,” according to the Collective.

A northern water snake sticks its head out of the Japanese knotweed pontoon held together by stainless steel mesh. (Alexandra Ionescu/Rhode Island Collective)

ecoRI News recently spoke, via Zoom, with the Collective’s six members about the project. Their structure was built using dried Japanese knotweed, broadleaf cattails, and bamboo for buoyancy, as alternatives to petroleum-based materials such as plastic and foam typically used to construct floating wetlands. A small amount of stainless steel wire mesh and cable holds the craft together.

The knotweed used to create the floating wetland was harvested in late winter as dry stems from Mashapaug Pond and Gano Park in Providence. Fertik said repurposing invasive species for the project’s pontoons removed some of their biomass from the environment and transformed the nonnative plants into a vessel to improve water quality and promote biodiversity. (The dead stalks weren’t capable of spreading their invasiveness.)

“The group didn’t want to use any plastic or synthetic materials. We wanted to use natural materials for buoyancy,” Muller said. “But we also want it to be reliable and not to, like, fall apart. And since this is, you know, our first time doing it, we decided to use the stainless steel, which can be used repeatedly, like if the organic material degrades and we need to take the pontoon out of the water, we can compost the knotweed and then use the same stainless steel mesh to put fresh knotweed in.”

The craft is home to 18 native wetland plant species: American bur-reed; bayonet rush; brown fruited rush; Canada rush; common cattail; Alleghany monkey-flower; blue flag iris; boneset; cardinal flower; flat-topped goldenrod; Joe-Pye weed; New York ironweed; northern water horehound; pickerelweed; swamp milkweed; buttonbush; silky dogwood; and steeplebush.

The floating wetland will remain in Ice Pond in Southborough, Mass., until Sept. 17. (Alexandra Ionescu/Rhode Island Collective)

Floating wetlands are artificial islands that host human-made ecosystems. They are designed to attract native species while helping to improve water quality. Suspended in water, the plant roots provide a home for diverse communities of algae, bacteria, fungi, and protozoans, known as periphyton. As the plants upcycle nutrients from the water into their roots, stems, leaves, and flowers, the periphyton provide nutrient uptake, filtration, oxygenation, and toxin removal.

Southern New England’s freshwater lakes and ponds, especially the shallow ones, are being stressed by development, wastewater overflows, old and failing septic systems, antiquated cesspools, and stormwater runoff carrying nutrients such as nitrogen and phosphorous from fertilizers and roadway pollutants such as polycyclic aromatic hydrocarbons.

By harnessing the natural ability of plants and microbes to absorb nutrients and break down contaminants, natural wetlands — and those created by concerned activists — help protect the region’s many waterbodies.

The members of the Collective said floating wetland ecosystems, like the ones created by nature, “heal water by regenerating the food web. The genesis of an ecosystem begins with microorganisms. We are learning how to initiate a propensity for nutrient cycling and learning how to create the conditions for a collaboration with the more-than-human world.”

The Collective’s 48-page PowerPoint presentation noted Indigenous communities built floating islands for hundreds of years by harvesting natural materials found in their surroundings. “By incorporating native plants from freshwater marsh and pond ecosystems, we are supporting a variety of other life forms,” they said.

Ice Pond, part of the 58.5-acre Elaine and Philip Beals Preserve, is a healthy ecosystem in little need of a floating wetland to pull pollutants out of the water, but it did give the Collective an opportunity to learn how floating wetlands create a habitat, observe the decay of the natural materials used to build the craft, and document the growth of the native wetland plants.

The Collective’s floating wetland will remain on the Southborough pond until Sept. 17. The Providence Stormwater Innovation Center has requested the craft’s presence for the ponds at Roger Williams Park.

The Collective hasn’t yet discussed the project’s future after Ice Pond, but the members would like to create a community project, perhaps in Roger Williams Park, where they could teach people how to make and use them. Floating wetlands could also help lessen the number of blue-green algae (cyanobacteria) blooms that plagued many ponds and lakes in southern New England.

Art on the Trails is an annual site-specific ecological sculpture park exhibition.

To watch a video about the project, click here. To watch a beautiful charcoal-drawing, time-lapse video, drawn by Ewald, that inspired the project, click here.


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  1. Cambridge did this 20 years ago in big filthy pond at Fresh Pond Reservoir. Turned a plan the dog park reviled and kept their dogs from to a pristine pond, the city put in a dog beach replete with teak benches for owners. Extraordinary transformation.

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