Combined sanitary sewage and stormwater runoff that would otherwise be discharged to the St. Marys and Maumee Rivers will be collected and temporarily stored in an approximately 5-mile long tunnel. The combined sewage and stormwater will be treated after the wet weather event has ended and the wastewater treatment plant has sufficient capacity.

Construction on the Tunnel Works Project began in 2017 and the system is anticipated to be completed and fully operational by 2025, which will reduce combined sewer overflows (CSOs) to the St. Marys and Maumee Rivers by 90 percent - from about 71 times per year to just four.

Diagram of the Tunnel Works Project design and function (City of Fort Wayne).