Flooding in Chicago has always been a possibility during warmer months. Now, with a warming climate, that threat is expanding. And so are the links between the global climate and neighborhood-level impacts. Since March, multiple rounds of severe storms have caused flooding, plus hail damage and even tornadoes. A warmer atmosphere can hold more moisture, and that moisture can turn into rainfall.
“This is a classic recipe for severe weather,” said Ashish Sharma, the Climate and Urban Sustainability Lead at the University of Illinois’ Discover Partners Institute. “Right now, it’s just happening a little bit more often.” The Metropolitan Water Reclamation District (MWRD) manages several lines of defense against floodwaters in Chicago and 128 suburbs. These include the Tunnel and Reservoir Plan, commonly known as “the Deep Tunnel”; over 35 stormwater reservoirs; and “green” infrastructure and storage projects with partners around the region.
Some backstory: According to Kevin Fitzpatrick, the assistant director of engineering at MWRD, the work of managing floodwaters begins before the rain even starts to fall.
“As part of (reversing the Chicago River), we created 76 miles of manmade waterways,” said Fitzpatrick. “In advance of a storm, we can let more water out of those canals downstream, and create about 5 billion gallons worth of storage in the canals.” During a storm, up to 11 billion gallons of water are captured and pumped to treatment plants before being returned to nature.
The system is set up well to handle massive amounts of water – if it can get there. In some areas of Chicago, aging sewer systems struggle to keep up with the volume of water during heavy rains, causing it to back up into neighborhoods. Working in an urban environment can make infrastructure upgrades difficult, according to Fitzpatrick.
The Chicago area is “a highly dense area, there’s not a lot of room to put in a new reservoir. So we’re having to get creative,” said Fitzpatrick. Beyond traditional and “green” infrastructure, there’s another area where improvements can be made: information.
Sharma is working on that with others through a new forecasting tool. Predicting when and where flooding will occur is a bigger challenge than just predicting rainfall, and he hopes to give more neighborhood-specific forecasting.
