by CHRIS ROGERS
There are some odd-looking things happening on the shore of Lake Winona. From the bandshell to the Franklin Street boat landing, big rolls of brush wrapped up in burlap are staked just off the shore, and swaths of dead grass are cordoned off with silt fence. It is all part of a pilot project to use the shoreline to grow native plants, support pollinators, reduce runoff, discourage ducks, and improve overall water quality.
Last week, a crew of volunteers, Minnesota Conservation Corps members, and contractor Gabe Ericksen cut down invasive buckthorn plants from the southeast shore of East Lake Winona and hauled them over to the north shore, where they rolled them in burlap and positioned them along the lake shore. Quizzical looks emanated from the bike path. People asked what they were doing.
These burlap-and-buckthorn rolls are meant to prevent waves from washing away new plantings of native reeds, rushes, irises, and arrowhead in the shallows along the shore. Ericksen hopes those water plants will spread along the shore, holding fast soil that wave erosion was slowly eating away, creating fish habitat, and absorbing some of the excess phosphorus that makes Lake Winona so full of algae and lake weed. “We killed two birds with one stone by using the invasive brush as our wave barriers,” he said. Onshore, the silt-fenced areas are places where Ericksen applied Roundup herbicide to kill the sod and prepare the soil for plantings of native prairie this fall. He and project organizers hope those deep-rooted native plants will catch runoff before it enters the lake, feed butterflies and other pollinators, and, with a thicker buffer of tall vegetation, make it more inconvenient for geese and ducks that they say pollute the lake — and the bike path — with their waste.
The project was spearheaded by Healthy Lake Winona, a citizen group whose goal is to clean up phosphorus and other pollution in Lake Winona and make the lake swimmable again — or more specifically, swimmable without the risk of duck-borne swimmers’ itch. The Winona City Council unanimously approved the project in May and agreed to pay for half of the $6,000 effort with money from the city storm sewer fund. Healthy Lake Winona donors funded the other half, and volunteers did most of the work.
Ericksen is a member of Healthy Lake Winona, and he described this effort as a sort of pilot project. Between the bandshell and the boat landing, there is a diversity of ecosystems along the shore, he said: wetlands, wooded areas, sandy soil, and places where the shoreline is lined with riprap. Healthy Lake Winona’s goal is to restore these areas to the sort of plant communities that might have grown there naturally: wet meadows, sand prairies, tallgrass prairies, and woodlawn plants. They are still trying to figure out what kind of rock-loving plants will do well in riprap. Healthy Lake Winona organizers hope that by testing out what native plants will succeed and look good at this small but diverse site, they could someday expand the shoreline restoration project to the entire lake. “We need to start re-vegetating the lake. That’s one of the things that will start to bring the phosphorus levels down and create habitat for fish,” Ericksen.
Under state law, the city can only allow so much phosphorus to runoff from the city’s storm sewer system into the lake each day, and plants that absorb those nutrients will help the city meet that requirement, Winona Sustainability Coordinator John Howard said.
Asked about the use of herbicides to kill grass and weeds at the site of the future prairie plantings, Ericksen said, “Roundup is the safest effective herbicide there is,” and added that there is a big difference between the judicious use of herbicide to transition to native plants and year-after-year application of herbicide. City crews have for years used herbicide to try to control weeds in the lake.
Is erosion that big of a problem on Lake Winona? “It’s somewhat slow, but it’s definitely happening,” Ericksen said. During his presentation to the council, he and other Healthy Lake Winona members showed off slides of spots where the shoreline is sloughing off and where trees are on the verge of falling into the lake.