PROVIDENCE — Polo Lake in Roger Williams Park has a new attraction, thanks to the efforts of some Rhode Island artists, designers, and environmentalists, Narragansett Indian Tribe members, and a botanist.
A hand-built floating wetland was launched last month. It was designed to raise awareness about the importance of wetlands and show how they work.
The June 15 event began with Lorén Spears, executive director of the Tomaquag Museum and a Narragansett Indian Tribe elder, delivering a land acknowledgement. She also discussed the importance of water “for our shared Earth.”
The buoyant raft holds 26 native wetland plant species. (Alexandra Ionescu)
A floating wetland is a passive nature-based solution inspired by the way wetlands have been cleaning water for millions of years, according to Alexandra Ionescu, an ecological artist who helped design and make the structure.
She noted floating wetlands help improve water quality by cultivating biodiversity and regenerating the food web by amplifying the natural processes between plants, sunlight, water, and other forms of life, from micro to macro scales.
Over the course of the next 16 months, 26 native wetland plant species, including buttonbush, cardinal flower, and swamp milkweed, will grow on the buoyant raft and create habitat for life above and below the waterline.
Below, the plants’ roots will work symbiotically with microorganisms to absorb phosphorus and nitrogen from the water column. Above, the plants will provide nectar, food, and habitat for insects and birds. The structure will also provide shade and oxygen for aquatic organisms such as fish, frogs, and invertebrates.
Polo Lake, based on water quality data collected by the Stormwater Innovation Center, has the highest phosphorus levels among the park’s ponds and is classified as a nutrient-impaired waterbody by the Rhode Island Department of Environmental Management.
On July 5, state officials advised people to avoid contact with Polo Lake and two other Roger Williams Park waterbodies, Elm and Cunliff lakes, because of blue-green algal blooms (cyanobacteria).
Phosphorus and nitrogen overloads from fertilizers can destabilize waterways by causing these toxic blooms and other water quality impairments that can harm aquatic life and deplete the water of oxygen. Stormwater runoff can also carry other pollutants, such as pesticides, oils, vehicle residue, debris, and heavy metals.
On July 9, state officials advised people to avoid contact with another Roger Williams Park waterbody, Deep Spring Lake, because of a blue-green algal bloom.
The project is designed to show how pollutants could be sucked from stressed waterbodies with a little help from human hands. (Beatrice Steinert)
By installing the constructed floating wetland, Ionescu said the group hopes to enhance the pond’s ecological functionality of nutrient cycling, where nutrients are absorbed for plant growth rather than cyanobacteria growth.
She said the group also hopes to use the structure to teach students and park visitors how “cultivating biodiversity can heal our waters, the vital role native plants play, as well as the often overlooked, and invisible-to-the-eye microorganisms — the fungal, bacterial, phytoplankton, and zooplankton communities — without which life on Earth would not be possible.”
A day after the craft was launched, Ionescu said a turtle was using the wetland to bask in the sun. A muskrat, plenty of dragonflies and damselflies, and red-winged blackbirds have also been observed on or around the wetland.
“During the first week, we experienced the first heat wave of the summer and we went there every day to water the plants,” she said. “Relieved that all of them made it, except the hempvines we planted in the corners. We went back and replanted them and now we will see what happens. The intention is guide their growth on the bamboo rods.”
The group plans on monitoring life on and around the floating wetland and Polo Lake in general for the rest of the summer. Group member Holly Ewald, a visual artist, is doing a summer program centered around the floating wetland with New Urban Arts kids and high school students.
This mini-wetland wasn’t the group’s first effort to raise water health awareness by building a floating habitat. Last year the group launched its prototype in Ice Pond in Southborough, Mass.
Both structures were 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 crafts together.
The Stormwater Innovation Center and the Providence Department of Parks provided support for the Polo Lake installation.
The handcrafted wetland will spend the next 16 months floating in the stressed lake. (Alexandra Ionescu)