In River Park on Chicago’s Northwest Side, a gently sloping riverbed covered with stones, sand and gravel occupies the former site of a small but historically important dam.
The 4-foot concrete structure created a waterfall – the last on Chicago waterways, in fact.
“There are other [waterfalls] in more landscape settings and some of our other parks and our lagoons and areas,” Chicago Park District project manager Lauren Umek told WTTW News last year. “But in terms of our lakes and river systems, this is the last waterfall in Chicago.”
And now it’s no more – the Army Corps of Engineers started demolishing the dam at the end of July 2018 as part of an ecosystem restoration project undertaken by the Corps, Chicago Park District and Metropolitan Water Reclamation District.
Constructed in 1910 to protect the riverbank from erosion, the dam was located where the North Branch of the Chicago River meets the North Shore Channel. The structure prevented aquatic wildlife from migrating up or down the river.
“So the fish are coming, swimming upstream, they hit that concrete wall and they’ve got nowhere to go,” Umek said. “They can’t go up to the north branch of the Chicago River.”
Today, the riverbed provides a navigable path for fish.
“We used a series of different rounded cobbles that are typically found in rivers,” said Jason Zylka, an ecologist with the Corps. “That structural diversity on the bottom of the river is really critical so the fish have places to hide, nooks and crannies for young fish to live, places where they go and find refuge so they can grow up and continue to live and reproduce.”
It’s a popular fishing spot for humans and birds alike. On a recent August day, several black-crowned night herons, an endangered species in Illinois, were fishing on the stony habitat.
Along the river, several invasive plants and trees, like European buckthorn, were uprooted and replaced with native prairie vegetation.
“We’ve planted that area with a diverse array of native grasses and wildflowers to help make that into a native prairie system,” Zylka said. “Similar to what would’ve been out here in historic times before this area was settled and turned into a park.”
The USACE said the riverbank restoration, which includes adjacent Ronan and Legion Parks, will take a few years and cost about $15 million of federal and local funds.
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