Are mushrooms the solution to the beach closings on Madison’s lakes?
Post by Christie Taylor on 8/23/2010 9:59am
A coalition of Madison non-profits hope to use the pollutant-filtering power of fungi to make the waters of Lake Wingra near Vilas Beach less hospitable for e. coli and other associated waterborne bacteria in the coming year.
The beach just re-opened last week after high levels of algae closed it on July 20. The month-long closing was, Friends of Lake Wingra chair Jim Lorman said, “unacceptably long,” and many chose to swim despite the risk.
Last year was a better year for the beach, following an experimental kill of invasive carp, but most years the beach closes an average of seven times per year due to e. coli and blue-green algae, thanks largely, Lorman said, to runoff from grassy areas where hundreds of Canada geese congregate and leave their droppings.
Lake Wingra also experiences other problems common to urban lakes, including high levels of sediment and salt, damaging to some native fish, and storm water runoff containing phosphorus-rich lawn fertilizers, which contribute to algae blooms.
Christina Cappy, a member of the UW-Madison chapter of Engineers Without Borders and one of the coordinators for the Clean Vilas Beach Coalition, said the first solution the group wants to build is a biofiltration garden. The basic design would include a solar-powered pump to pull water out of the swimming area. The water would then flow back downhill through a series of terraces containing native wetland plants and fungi, and re-enter the swimming area cleaner than it started.
Wetland plants are already widely used to filter sediments and excess nutrients in rain gardens and other storm water projects around the country. And mushrooms – particularly oyster, shiitake, and a variety called shaggy mane – can fight a number of waterborne pathogens, including e. coli and staphylococcus.
Mushrooms would pop up at “certain times of the year,” the group says, but much of the work of filtration will actually be done invisibly by mycelia, a network of branching fungal structures hidden in the soil.
The coalition partners include Engineers Without Borders, who will oversee the functional design, as well as Friends of Lake Wingra, the Madison Area Permaculture Guild, the Yahara Lakes Legacy Partnership, Yahara CLEAN, and the Town and Country RC&D Water Issues Team.
Eventually, Cappy said, they’d also like to build a floating island along the western edge of the swimming area, also filled with native water plants, to protect the water from storm water entering the lake to the west.
A third proposal is a fungal buffer along the grassy edges of the beach, with most of the work again being done by underground networks of mycelia.
But most importantly, Lorman says, the coalition’s vision is an interactive, educational feature, which just happens to also clean the water.
“This will clean the water and serve as a demonstration for what is possible on a larger scale,” he said. “Hopefully we gather enough data to determine this is an approach we can use here or elsewhere in the Yahara watershed.”
And in the meantime, he said, the project would make the lakes problems and their solutions more visible to the people who have a stake in its health.
“Regardless of how effective this is, we have every reason to believe it’s going to contribute to water quality.”
And, landscape architect Lauren Brown said, the coalition wants community input.“It’s really a creative process at this point,” she said.
At a meeting on the beach Saturday morning, Wingra area residents collaborated on several ideas for how such a structure could also be a fun, interesting place for beachgoers and zoo visitors to learn more about the ecology of the lake, and “positive, hopeful” solutions for the lake’s problems.
Proposals included wildlife scavenger hunts, intricate sculptures spiraling the water back into the lake, and even an homage to one of the Ho-Chunk names for the lake, Ki-chunk-och-hep-er-rah or, “place where the turtle comes up.”
Several said they hoped the garden could be hands-on, welcoming, and a place that could teach without “the traditional Plexiglas sign.”
Brown said she expects the coalition to host more opportunities for community involvement in the fall, after narrowing down to a set of four or five conceptual designs. Cappy said Engineers Without Borders would begin looking at the exact specifications for the project in the fall semester, once students had arrived back in town and the year’s members could meet.
Eventually, she said, the group would also like to install a floating barrier to filter bacteria and other pollutants from storm water entering the lake to the west, and a “buffer” of fungi-rich soil between the beach and the grassy areas where the geese congregate.
For more information or to get involved in the project, contact the coalition at CleanVilasBeachCoalition@gmail.com
Christie Taylor (@ctaylsaurus) covers science, environment, and, depending on the season, state politics for dane101. She verbs a lot of nouns, including rollerskates, radio, and Kurt Vonnegut. A Madison native, she's not sure she'll ever quite manage to leave Wisconsin, and that's just fine by her. Contact her at firstname.lastname@example.org.