Chicago has been treating Lake Michigan like a giant toilet tank since it engineered a crude sewer system to suck from the lake about 6 billion gallons of water per day, a flow big enough to drain a body of water the size of Lake Winnebago in a single summer.
You can think of that colossal water grab as a super-size flush, inside a continent-sized commode. Chicagoland's raw sewage once plunged into the man-made Chicago Sanitary and Ship Canal, and that canal whooshed the Windy City stew into the Mississippi River and down to the Gulf of Mexico, Chicago's toilet bowl.
