Chicago Flood Mitigation Scrambles to Keep up With Climate Change

In an article for the Chicago Tribune and republished in Governing, Michael Hawthorne and Adriana Pérez describe how Chicago’s efforts to mitigate higher flood risks are not keeping up with the effects of climate change.

The Deep Tunnel, a $3.8 billion subterranean flood control project officially known as the Tunnel and Reservoir Plan (TARP), is designed to prevent flooding and keep wastewater and industrial runoff out of local waterways. But earlier this month, during a heavy storm, 20 overflow pipes in Cook County spewed runoff and waste. “Recent storms suggest rain can now fall so quickly that stormwater tunnels can’t move runoff to the reservoir fast enough to prevent sewage overflows and basement backups in the 252 square miles of Chicago and County served by the main part of the system.”

The prognosis is grim: “In 2010, [Don] Wuebbles and other scientists hired by former Mayor Richard M. Daley concluded that rains of more than 2.5 inches a day, the amount that can trigger sewage dumping into Lake Michigan, were expected to increase by 50 percent by 2039.”

As the authors point out, “Like so many other societal ills, the consequences hit the poorest Chicagoans the hardest. After a major storm in 2013, city officials determined the damages were concentrated in low- and middle-income census tracts on the West and South sides, similar to where many 311 calls originated after the more recent storms.”

The Water Reclamation District is partnering with local governments to build more retention basins, particularly in areas where flooding has occurred repeatedly.