Heavy rain overwhelmed Chicago’s aged infrastructure yesterday, causing sewage to back up into homes and burst through manhole covers in the middle of the street. The videos make for pretty horrifying viewing, but equally horrifying is how the pressure on the system was alleviated: through a last resort measure that allows runoff and wastewater to be released into Lake Michigan. And this isn’t a one-off, as Chicago has experienced ever increasing rainfall, over 21 billion gallons of wastewater and runoff was released into Lake Michigan between 2007 and 1012.
It’s a pretty disgusting problem, and one has to wonder to just what extent the wastewater is responsible for shutdowns of the beach and waters in recent years (now reassuringly relabeled “Swim At Your Own Risk”). Multiple times the popular beaches along the lake have been closed, or swimming has been restricted, as the parks service warns against exposure to high bacteria levels in the Lake.
The problem is one of a sorely antiquated infrastructure that can no longer meet the higher demands of a larger city with heavier rainfall. The Chicago Tribune explains, “[l]ike many older cities, Chicago… long ago built sewers that combine waste from homes and factories with storm runoff. When it rains, sewers quickly fill up and spill into local streams through overflow pipes. If waterways are saturated to capacity, the locks and gates to Lake Michigan are opened to reduce flooding.”
Meaning it’s not just Lake Michigan—sewage is first pumped into the Chicago River and other local waterways. The Tribune cites that it can take just two-thirds of an inch of rain to cause an overflow into the waterways. But Chicago has been having much more rain than that, and far more frequently. Two and half inches of rain will cause runoff into Lake Michigan, and storms of that severity are expected in “increase by 50 percent by 2039.”
Slow-moving projects are in place to update the infrastructure—both in terms of flood and waste management, but until those are complete the wastewater will continue to flow, and the Chicago Department of Water Management will continue to resort to adding “more bacteria-killing chlorine to lake water before pumping it to households and businesses.”
Via Chicago Tribune
Lead image (cc) Flickr User gcfairch