The Metropolitan Water Reclamation District of Greater Chicago’s (MWRD) Tunnel and Reservoir Plan (TARP), also known as the Deep Tunnel, received the AEG Outstanding Environmental and Engineering Geologic Project award for 2025. The Association of Environmental and Engineering Geologists (AEG) presented the award at its 68th Annual Meeting in September 2025 at the Westin Hotel in Chicago. The award recognizes TARP as a model for pollution and flood control infrastructure.
TARP is one of the largest public works projects focused on reducing flooding and improving water quality. For over forty years, it has helped prevent billions of gallons of stormwater and sewage from entering Chicago’s waterways and Lake Michigan. The system includes four tunnel networks that total 110 miles beneath the city.
Before TARP, combined sewer overflows (CSOs) often released untreated stormwater and sewage into local rivers and sometimes Lake Michigan. This caused environmental and public health issues. TARP now intercepts these overflows and stores the water in large reservoirs during storms. The water is later treated at reclamation plants before being released…