Three Rivers Protection & Overflow Reduction Tunnel (3RPORT) & the Tunnel Works Program
Fort Wayne City Utilities has hired a contractor to construct a large tunnel that will be located in the bedrock below the city. There will also be an associated network of pipes nearer to the surface of the ground. This system, known as Tunnel Works, will collect and transport sewage from locations where Fort Wayne’s combined sewer system might overflow during wet weather to the sewage treatment plant. Tunnel Works is the capstone in the Long-Term Control Plan for reducing the amount of combined sewage (a mixture of sanitary sewage and stormwater) that is discharged into Fort Wayne’s rivers every year.
The Tunnel
- The route generally runs parallel to the St. Marys and Maumee Rivers
- 3RPORT will be constructed in bedrock approximately 200–220 feet below ground using a tunnel boring machine (TBM)
- One working shaft to place the TBM underground, approximately 30 feet in diameter; one retrieval shaft to remove the TBM; and a shaft for a pump station that will remove wastewater from the tunnel
- 5 miles of tunnel lined with concrete, 16 feet finished diameter, to collect and transport combined sewage
- Seven drop shafts, 4–8 feet in diameter, to direct sewage from near-surface sewer pipes into the tunnel
Near-Surface Consolidation Sewers
- Construction of near surface “consolidation” sewers, each with a diameter of 48–84 inches, to direct sewage to drop shafts. Construction of consolidation sewers will use the traditional method of open-cutting a trench and installing pipe
- Two miles of additional sewer construction at the south end of the tunnel using the traditional trench construction method
Outcomes
- Completion of 3RPORT and Tunnel Works program will reduce combined sewage overflows to St. Marys and Maumee Rivers by 90%, from about 71 times in a typical year to just four
Timetable & Cost
- 2014–2016: Design of overall system completed, including soil and rock drilling and testing, public outreach and finalizing the tunnel route. Bidding for construction occurred in February 2017
- 2017: Construction began.
- 2025: All parts of Tunnel Works system will be completed and operational.
- Approximate cost: $188 million for the 3RPORT and drop shafts
Questions?
For questions about the Tunnel Works program, please email City Utilities at [email protected].