Helping to prevent the release of untreated water in streams, Lake Michigan, and people's basements
It’s one of the largest civil engineering projects in the world—the Chicago Tunnel and Reservoir Plan (TARP) is the City's answer to water pollution and sewer backup problems. A system of deep, large diameter tunnels and vast reservoirs, the TARP is designed to reduce flooding, improve water quality in Chicago area waterways, and protect Lake Michigan from pollution caused by sewer overflows.
The TARP includes four tunnel systems, totaling 109 miles (175 kilometers) of tunnels, 8 to 33 feet (2.4 to 10 meters) in diameter and 150 to 300 feet (46 to 91 meters) underground, capture and store combined stormwater and sewage that would otherwise overflow from sewers into waterways in rainy weather. This stored water is pumped from the TARP to water reclamation plants to be cleaned before being released to waterways. Our work on the TARP began with the overall planning and geotechnical investigation of the tunnel and reservoir’s system—and has continued through detailed design and construction management services for multiple segments and structures of the overall program.
Success of the TARP is evident by dramatic improvements in the water quality of the Chicago River, the Calumet River, and other waterways. Game fish have returned, marinas and riverside restaurants abound, river recreation and tourism are booming, and waterfront real estate values have increased.
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