Sequiota Park, a 28-acre park on the southeast side of town, has a number of picturesque features that make it one of Springfield’s favorites: walking trails, playgrounds, caves and the iconic “big rock,” to name a few.
One prominent element that makes Sequiota special is its lake. The lake is a part of a much larger watershed that stretches north all the way to Sunshine Street, so runoff from many homes and businesses flow downstream and end up at Sequiota Park via cave systems.
With this runoff comes a slew of chemicals and nutrients that can be detrimental to the habitat. If you’ve been to Sequiota Park and seen the lake, the detriments are evident. Algae blooms have dominated the surface of the lake for years.
Sarah Davis is a stormwater specialist with the City of Springfield’s Department of Environmental Services. She and her colleagues at the Water Quality Division knew they needed to get creative to solve the algae problem.
“Algae blooms are a symptom of an excess of nutrients in a storm water system,” Davis said.
Phosphorus and nitrogen especially contribute to the problem. These nutrients can come from a variety of sources, the main offenders being lawn fertilizers.
The lake at Sequiota Park was an easy choice for Davis and her team to start a new project because algae blooms have been a significant, ongoing problem there. After several remedy attempts — including chemical treatments and dredging — the Water Quality Division turned to a new solution in the form of floating wetlands.
Floating wetlands are artificial aquatic habitats that aim to mimic natural wetlands. Around 45 of these roughly 8-by-10-foot structures are anchored to the bottom of the lake. The project launched in May 2018 as a collaboration between City of Springfield and the Springfield Park Board.
According to MidwestFloatingIsland.com, a floating wetland can have a number of applications beneficial to a watershed, including wetland restoration, erosion control and carbon sequestration.
City of Springfield built the wetlands from repurposed wooden frames, which sandwich layers of geotextile — a strong synthetic fabric that can stabilize loose soil and minimize erosion — that wrap around recycled plastic bottles to stay afloat. Each wetland has a variety of native plants on it, including irises, pickerelweed, rose mallow and arrowwood. The plants are surrounded by chicken wire to prevent waterfowl from landing on the structures and eating the plants. Clusters of four to five wetlands float together on the lake, fixed to each other by carabiners and leftover metal posts from traffic signs.
Springfield is not the only area using floating wetlands. An Ohio county has seen their floating treatment wetlands be effective in increasing water quality in the Great Miami River Watershed by increasing nutrient uptake, lowering suspended soil and promoting biodiversity.
Floating wetlands make for a valuable solution to algae blooms and excess nutrients because they serve multiple functions, including increasing pollination in the lake ecosystem, oxygenation and an added element of beauty to the park, according to Davis.
Additionally, the wetlands make for a valuable habitat to the animals that call the park home. As roots grow into the water below, they create a microbiome of bacteria that becomes a valuable source of food for the fish.
“What we try to do in (the Water Quality Division) is find these unique practices that provide multiple benefits to the community,” Davis said. “The floating wetlands are a good example of what we call, in a larger term, ‘green infrastructure.’ Green infrastructure are practices that mimic nature and biological processes.”
Despite the floating wetlands’ efforts to combat the issue, the lake at Sequiota Park continues to bloom.
Ongoing sampling shows the wetlands “have not made a big dent” in the algae problem, Davis said.
Davis said she suspects there just aren’t enough wetlands in the lake to make a meaningful difference. Around 5% of the lake’s surface — several thousand square feet — would need to be covered by plant matter to take up all the nutrients in the system.
Regardless of nutrient uptake, the floating wetlands give a variety of benefits to the lake and surrounding park. One is an educational gain. Signs posted in Sequiota Park can help visitors learn about water quality, biodiversity and the lake’s ecosystem.
There are aesthetic benefits too; the wetlands provide both color and texture to the lake. Other methods, such as chemical applications, may temporarily reduce algae but do not offer any of those other types of benefits, Davis explained.
Davis said there are several things Springfield residents can do in order to do their part to keep local waterways clean:
Get your soil tested. The first step to avoiding over-fertilizing is knowing what nutrients your soil already contains. You may not need fertilizer in the first place.
Purchase a rain barrel, which collects rain runoff from your rooftop. Use the rainwater to water your plants. The City of Springfield offers a rebate for rainwater collection.
Participate in the City of Springfield Adopt-a-Stream program to pick up trash and keep waterways clean.
Do not dump chemicals down storm drains. Springfield’s storm drain systems do not lead to a water treatment plant or sewer. All fluids going into the stream end up in our creeks and rivers.
Pick up after your pet. Pet waste is a significant issue in water quality, especially in urban areas such as downtown Springfield.
Follow Diana Dudenhoeffer on Twitter, @kisstein
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