The massive system of tunnels and reservoirs was built to contain Chicago’s flood water, protect area rivers and Lake Michigan. Now, there’s a risk that suburbs will flood and sewers will overflow into Chicago waterways.
The Thornton Reservoir in South Holland sits nearly full Monday after a weekend of intense rain.
For the first time in history, Deep Tunnel, Chicago’s massive system of underground tunnels and reservoirs designed to hold flood water, is almost completely full after a weekend of heavy rain.
Built over more than a half-century, Deep Tunnel sends floodwaters from Chicago and nearby suburbs through more than 100 miles of tunnels into three reservoirs located just outside of the city. It was designed to help protect area rivers as well as Lake Michigan.
