The project just completed work on one of the major reservoirs used by the system. The Thornton Reservoir is a limestone quarry that can hold 8 billion US gallons (30,280,000 m^2)
Here's a video of the reservoir taking in 400 million gallons after a heavy rainfall last week:
That's cool. I used to live close enough to Thornton Quarry to feel the blasts shake our house daily at 4:00 PM. It's a huge open limestone quarry. The photo in the article does not do it justice, and only shows the rectangular block north of I-294. Here is the full system:
I went on a tour to the bottom of the reservoir before it opened and it is massive. An engineering feat started almost 30 years ago coming together with this site and several move over the next decade to add capacity to the system in different areas of Chicagoland.
Here's a video of the reservoir taking in 400 million gallons after a heavy rainfall last week:
http://www.dnainfo.com/chicago/20151203/south-chicago/watch-...