One of Chicago’s most impressive Engineering marvels is invisible to most of the cities visitors. It, like many other cities, uses combined sewage and wastewater collection system. During heavy rain, this allows city avoids flooding but also means that overflow of sanitary waste is flushed into surrounding rivers and drainage basins.
In 1975, the cities engineers devised a solution on a massive scale to this problem and the Chicago’s Tunnel, and Reservoir Plan started constructions.
The eventual goal of was to hold 17.5 billion gallons of wastewater deep underground in storm events. The project is now seens as one of the engineering marvels of the 20th century
2016 sees operational testing completed on the final phase of the project at Thornton Quarry. This massive limestone put can contain a little under 8 billion gallons of water, making it the world’s largest stormwater reservoir.
Now the plan has entered its final phase it is on track to be completed by 2029.
Want to find out more. Visit Interesting Engineerings detailed look at the history of the project and the infrastructure challenges it faces.