Science & Nature
Sewage Overflows Into the Chicago River Are Rare, But New Warning System Will Alert Paddlers and Other Users When to Steer Clear
An outfall on the North Branch of the Chicago River. (Patty Wetli / WTTW News)
Chicago’s wastewater management system has come a long way since the days when the city pumped its sewage straight into the Chicago River (an improvement itself upon sewage being dumped in the streets).
But there are still occasions when the city’s sewers — which carry both wastewater and stormwater in the same pipe — become overwhelmed, typically during heavy rains, and untreated wastewater is discharged into the river and its channels instead of being whisked away to a treatment plant.
These combined sewer overflow events, as they’re known, could occur at any of the 184 outfalls within the city. And while they’ve become less common in recent years — falling from 62 such events in 2010 to 12 in 2023 and just 1 in 2024 — with more folks canoeing, kayaking, rowing and fishing in the waterway than ever before, the potential remains for people to unknowingly paddle or cast their line into pollutants from overflows.
The concern is that if an overflow occurs during a heavy storm at, say, 10 p.m., the next morning a kayaker could head out under sunny skies and be completely unaware that untreated wastewater has entered the river, said John Quail, director of policy and conservation for Friends of the Chicago River.
A new notification system is being proposed at boat launch sites that would alert people to overflow events, warning them to avoid contact with the water. Development of this notification system is one of the requirements included in a permit issued to the city by the Illinois Environmental Protection Agency in 2024.
Currently, people can subscribe to overflow alerts from the Metropolitan Water Reclamation District (MWRD), but these messages only state that an overflow has occurred somewhere within the MWRD network, which extends to outfalls beyond Chicago. People then have to navigate to a website to find out the overflow location, which could turn out to be along the Des Plaines River, for example.
It’s a clunky process, according to users, and one that a sizable number of people aren’t subscribed to, anyway. The goal of new system is to make alerts more visible and accessible to Chicagoans.
The Illinois EPA permit also requires advanced monitoring of 11 outfalls. (Credit: Friends of the Chicago River)
During a virtual presentation held Wednesday night, representatives from Chicago’s Department of the Environment, the Department of Water Management and Friends of the Chicago River outlined plans for a pilot program to introduce the new notification system.
What’s being proposed is a combination of warning lights and signage. During an overflow, the light would flash red, and for 24 hours after the overflow, the light would flash yellow, serving as a signal that people should postpone recreational activities.
The lights would be activated by data from MWRD and would be easier to implement, from a human resources standpoint, than other systems, like the color-coded flags Boston uses along the Charles River, said Jared Policicchio, Chicago’s deputy chief sustainability officer.
Four sites have been identified for a pilot program: boat launches at River Park, Clark Park, Ping Tom Park and Park 571 (in Bridgeport, home to the Eleanor Boathouse).
Any public launch built in the future will incorporate the notification system into its design.
Attendees at the virtual meeting, largely members of the Chicago rowing community, had a few suggestions for tweaks to the pilot program, including adding notification stations at access points such as the Wild Mile and somewhere along Downtown’s Riverwalk. They also recommended operating the notification system beyond the proposed months of April to October, noting that rowing programs have boats in the water in March.
A second, in-person public meeting about the system will be held March 26, 6 p.m., at Horner Park, with advance registration requested.
Contact Patty Wetli: @pattywetli | (773) 509-5623 | [email protected]
