The Wild Mile: Floating Wetlands Restore Diverse Wildlife to the Chicago River

Deep in the heart of urban Chicago, a network of floating wetlands is restoring native wildlife habitats, increasing biodiversity, and encouraging recreation along the north branch of the Chicago River.

Known as The Wild Mile, the interconnected islands were installed by grassroots environmental restoration organization Urban Rivers in 2017 and have since been dubbed the world’s first floating eco-park.

“We were really just looking at this underutilized space and seeing the potential for people to come and connect with their river system in a way they didn't get to throughout Chicago,” says Research Director Phil Nicodemus. “We wanted to create community around these new spaces so people would come here and understand more about the river system than they did before. Hopefully, they come away realizing this is a natural resource that’s ready to be retaken by people and wildlife.”

Interspersed with publicly accessible boardwalks that provide access to the river for recreation like kayaking, the floating gardens are comprised of environmentally neutral materials like HDPE plastic pontoons, coconut husk, porous clay aggregate, stainless steel, and a sustainable treated wood called Kebony.

The Wild Mile. Credit: Urban Rivers

Home to approximately 30 species of native plants—including blue vervain, swamp milkweed, buttonbush, greater angelica, and various types of river rushes—the wetlands help filter the water via their root systems and provide important habitat for wildlife and pollinators. Muskrats, beavers, ducks, herons, fish, mussels, snapping turtles, monarch butterflies, great black wasps, and bees are just a few of the creatures that have benefited from these habitats.

Together, The Wild Mile and its inhabitants help combat what Nicodemus calls “urban river syndrome,” a phenomenon caused by more than a century of urban development and industry in Chicago.

“A lot of these waterways have been channelized, dredged, and really confined to a certain box,” he explains. “They want this to be the box in which ships move up and down. They're not going to let it flood. They're not going to let it move its banks. They're not going to let little side pools of water sit around for a while. They're taking away absorbent ground and replacing it with impermeable surface. Those things are very hard on ecosystems.”

Abundant concrete, high seawalls, artificial lighting, and pollution are all factors that have historically made the Chicago River inhospitable for plants and wildlife. Nicodemus says the health of the river has improved markedly in recent years, with fish populations improving from just 10 in 1974 to more than 75 today. However, chemicals from road runoff, refuse from riverside industry, and human fecal waste from combined sewer overflows continue to create concern for the health of the river system.

“In an urban environment, all the stuff your car spits out, all this fossil fuel generation, it’s all going to stick to walls, surfaces, pavement, tree leaves, and all these other things, and when it rains, it's all getting washed into the sewer system,” Nicodemus says.

Once native to the river, wetland habitats serve important environmental functions like removing pollution from the water, preventing erosion by storing water, stabilizing shorelines, and providing habitat for wildlife. These benefits not only influence urban Chicago, but also help protect water quality throughout the vast network of waterways connected to the Chicago River, including the Des Plaines, Illinois, Calumet, and Mississippi rivers. Activity on the Chicago River can also help—or harm—the Lake Michigan watershed, which provides drinking water to more than 10 million people.

“Whether we realize it or not, the health of all these other organisms is also the health of us,” says Nicodemus, who adds that the root systems of the floating wetlands have helped reduce excess phosphorus and nitrates in Chicago River by up to 7% during the growing season. “There is no environment that’s not intricately connected to the rest of its region and by making a city this big, impassable, immovable object and not letting nature breathe through it, you're creating [these issues.]”

Like many urban river systems, the Chicago River is regularly cleared of natural materials like fallen trees, leaves, and other debris that make up wetland ecosystems. To help create a fully cohesive habitat, Urban Rivers has harvested nearby invasive trees and anchored them in the water near the wetlands to provide an environment for algae and microbes to grow. These organisms are important food sources for fish, the addition of these woody habitats helps support the greater food chain.

“[Microbes and algae] are what little fish are eating, then bigger fish are eating the smaller fish, birds are eating those fish, and so on through the whole ecosystem,” says Nicodemus. “That’s just a simple piece where we were using materials that were already on site that were going to get wasted anyway and turning them into pieces of habitat.”

The Wild Mile. Credit: Urban Rivers

Part of ensuring The Wild Mile fulfills its mission means encouraging residents of riverside communities and beyond to engage with the wetlands through community activities and outdoor recreation. To that end, Urban Rivers hosts regular yoga nights, acoustic jam sessions, workshops, and educational seminars.

Visitors are also invited to help caretake The Wild Mile through volunteerism, which includes tasks related to wetland maintenance like removing invasive species and collecting data on the birds, fish, bugs, and trash present in the river.

With the help of its many partners, including Shedd Aquarium, National Geographic, and the City of Chicago, Urban Rivers has expanded to three additional project sites throughout the Chicago River system. These sites are located at Bubbly Creek, a notoriously polluted section of the south branch; the popular River Park, where the floating islands help stabilize vulnerable shorelines; and on the Prologis industrial property along the south branch, made possible by a public-private partnership.

The Wild Mile has been funded primarily through approximately $3.2 million from the City of Chicago’s Open Space Impact Fee fund, a tax placed on new residential units that goes toward the construction of new local parks and greenspaces. Funding for Urban Rivers’ other locations was awarded primarily from the Chi-Cal Rivers Fund via the National Fish and Wildlife Foundation. Total costs for the projects are expected to reach approximately $50 million.

In recent years, Urban Rivers has collaborated with organizations all over the world to help them plan for their own networks of floating wetlands. So far, the organization has shared research and information with organizations in Baltimore, Maryland; Boston, Massachusetts; and Seattle, Washington, and helped provide general guidance to organizations in Tampa, Florida; Seattle, Washington; Tulsa, Oklahoma; Michigan City and Fort Wayne, Indiana; Milwaukee, Wisconsin; and Paris, France.

“We're finding slowly but surely that all these other urbanized waterways throughout the world are really interested in this kind of stuff,” says Nicodemus. “All these places have very similar issues, so it makes sense that people are always looking for a guiding light and for a way out of their industrial legacy that a lot of these waterways face.”

Visit urbanriv.org.