The Chicago area was hit last week by numerous storms that dumped inches of rain. In a metropolitan area, where does all this rain water go? The Metropolitan Water Reclamation District of Greater Chicago described what happened in an email yesterday:

As the Chicago area grew on the shore of Lake Michigan and inland across swamps, prairie, and forests, where would all the water go? Urban development and suburban sprawl tends to flatten landscapes, eliminating natural settings that help drain water. Humans can adjust, adding retention ponds and drainage flows and permeable surfaces and setting aside some land to be open or “natural.”

The results are cited above. Multiple storms lead to inches of rain. The ground was soaked and storm sewers were full. The water has to go somewhere. Some of it ends up in a former quarry with over 7 billion gallons of water. Drivers who passed over the watery quarry posted pictures on social media. It also ends up in other reservoirs and in local waterways.

For the residents of the region, this hopefully led to fewer flooded streets and basements. (Though I saw plenty of pictures of this as well.) All that engineering and money hopefully drained the water away from everyday human activity. Water may be a precious resource but too much water can disturb metropolitan activity so the engineering and water mitigation efforts will continue.