Whenever Chicago gets a lot of rain or there’s a significant snowmelt, the Chicagoland water management agencies must dump excess wastewater into the lake and river in order to prevent flooding. It’s because of practices like these that the city reversed Chicago River’s flow in 1900 to avoid contaminating our drinking supply. As a result, a significant amount of ‘nutrient pollution’ from Chicago travels down the Illinois and Mississippi rivers and collects in the Gulf of Mexico in a dead zone roughly the size of New Hampshire.
The Metropolitan Water Reclamation District of Greater Chicago tracks the release of raw sewage released in to Chicago area rivers. Through this application, citizens of Chicago are informed about the current status of the rivers. Since January 1st 2007, raw, untreated sewage has been dumped in to rivers on 522 days. Data comes from scraping the Metropolitan Water Reclamation District of Greater Chicago portal on Combined Sewer Overflows.