How reversing the Chicago River reshaped some of the richest ecosystems in Illinois

Engineering feat completed 121 years ago this week was a watershed moment in growth of metropolis—and for region’s natural landscape. Here’s what’s being done today for "Chicago's Grand Canyon."

It’s the stuff of legend—Chicago reversed the flow of its river so it could preserve Lake Michigan as a source of drinking water. The Chicago Ship and Sanitary Canal, completed 121 years ago this past Saturday, sent sewage south and west, first to the Des Plaines River and then into the Illinois River.

“It was long before the Clean Water Act or anything like that,” said Paul Botts, President and Executive Director of The Wetlands Initiative, a Chicago-based organization that designs, restores and creates wetlands. “Suddenly this massive city was sending every single day routinely millions of gallons of raw sewage through the canal, literally at the start of the Illinois River and on from there.”

Much has been written about the threat of invasive species like Asian carp coming up the Illinois and into the Great Lakes basin. But the reversal had much more of an effect on the inland ecosystem than on the lake ecosystem. In terms of water levels, Lake Michigan-Huron (Lake Michigan and Lake Huron are one lake, connected at the Straits of Mackinac) might rise by only about 2 inches with water from the Chicago River.

“If the Chicago diversion stopped tomorrow, the modern Illinois River would lose some of its modern flow,” Botts told me. “Enough to make a big difference, though exactly how much is a tricky question because of newer factors like suburban sprawl.”

The Illinois River teemed with life in the 19th century, well known for its hunt clubs and freshwater mussel industry. The Chicago diversion flooded many of the river’s backwaters, and many of those areas were later leveed off and drained for agriculture.

“In the accounts of the voyageurs, they were boggled by the diversity of waterfowl and everything else,” Botts says.

Today the Illinois River Valley, though, is gaining some of that astonishing habitat back, thanks in part to restoration efforts like The Wetlands Initiative’s work at Dixon Waterfowl Refuge in Putnam County, about a two-hour drive west-southwest of Chicago. There agricultural land quickly reverted to its natural wetland state, and birds and wildlife were quick to return. The refuge includes more than 630 native plant species, and at least 270 bird species have been observed. Meanwhile, the river itself is healthier due to 50 years of federal and state clean water laws.

“It’s a huge place,” says Josh Engel, founder of birding tour company Red Hill Birding. “It’s very well set up for visitors with an amazing tower. It’s great for birding because you get to see so much of the lake.”

Farther south, Emiquon National Wildlife Refuge, is another place where restoration activities have taken place and where tens of thousands of ducks and geese congregate in spring and fall. Back upstream at Dixon, Engel described seeing “huge numbers” of Northern Pintails and Greater White-fronted Geese on a recent visit, as well as Mallards.

“There were 8,000 to 10,000 Mallards,” Engel told me. “People may not be too excited by a Mallard, but when you see numbers like that it’s amazing.”

The site gives a glimpse into what the Illinois River once was—and may be in the future. Botts says the Illinois is an “extremely productive river” and on most days the treated effluent that goes into the river isn’t an issue.

“I’m a Chicago guy born and raised, and all I knew was the 5th grade outing to Starved Rock,” Botts says. “Today the Illinois River Valley is Chicago’s Grand Canyon, or it should be Chicago’s Grand Canyon.”

What happened on the Lake Michigan side of the story

When I started this piece, I thought the Great Lakes side of the river reversal story would perhaps be more compelling because of the notable threat of Asian carp. And there certainly was an immediate effect—the canal construction and drainage of the watery Chicago portage known as Mud Lake did remove some of the wetland ecosystem that once surrounded Chicago.

“That was probably fantastic habitat for birds and fish,” says Joel Brammeier, President and CEO of the Alliance for the Great lakes.

Brammeier told me the biggest impact came from cutting Chicago waterways off from their natural flow into Lake Michigan-Huron.

“All the coastal wetlands and riparian areas of the Calumet and Chicago rivers, in addition to being hardened by industry, all of that was just cut off in Chicago,” Brammeier says. “All that supply of freshwater habitat and estuary that exists along every river mouth was just cut off.”

Places along the Chicago lakefront are not quite what they once were more than a century ago—or could be. Though vast numbers of waterfowl occasionally gather in the lake at sites like Steelworkers Park on the South Side.

“I would guess the mouth of the Chicago River itself probably would have been amazing birding,” says Josh Engel of Red Hill Birding. “Those estuary ecosystems are great, with shifting sand bars and rich marine life.”

Brammeier points to projects in Detroit, Duluth, Minn., and Milwaukee where freshwater estuaries are being restored, projects not possible due to the channelizing of Chicago waterways.

Chicago still faces water issues today, as anyone whose basement has flooded can attest (two big exasperating, inundations for me, one in September 2019 and another in May 2020). There is another piece to be written in the future about the mess of our combined sewage outflow conundrum, opportunities for green infrastructure and progress on the Deep Tunnel project.

In terms of invasive species, our greatest threat remains in the form of Asian carp. The goal of the Alliance, which works to protect the fresh, clean and natural waters of the Great Lakes, is to stop live fish from moving north by erecting barriers. The most immediate objective is less about re-reversing the Chicago River and more about preventive measures.

“What’s most important is we get protections built quickly at Brandon Road Lock and Dam [near Joliet],” Brammeier says. “It’s not the same as separating [the watersheds] permanently.”

Special thanks to Kara Morrison for contributing research for this piece.

TWiB Notes

Jeff Bilsky and Amanda Tichacek found a stunning number of European Goldfinches during the Waukegan Christmas Bird Count on Jan. 1. The introduced species has been breeding in sections of Illinois and Wisconsin for most of the last two decades. The total of at least 95 may be a record for a single sighting of the species in North America……Chicago area birder Ben Sanders traveled to all of the lower 48 states on his way to a total of 678 species in 2020. That placed him fourth nationally, according to data from eBird…..The American Birding Association has named the Pileated Woodpecker as the 2021 Bird of the Year…..The Illinois Ornithological Society will host an online panel discussion featuring Big Year birders from across the state on Tuesday, Jan. 12., at 7 p.m.

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