Crews digging the two main shafts for Fort Wayne's Three Rivers Protection and Overflow Reduction Tunnel have only about 140 more feet to go before they're ready to start drilling.
The smaller working shaft, which is where workers and some equipment will enter and exit the tunnel site, is currently about 80 feet deep and has about 140 feet left to go, said TJ Short, City Utilities' senior program manager for the project. The larger pump station shaft is 70 feet deep, Short said, with about 130 feet left to excavate. Both shafts are at the work site on Dwenger Avenue near the city's water pollution control plant.
The pump station shaft is part of what will pump the water collected by the tunnel into the treatment plant, Short said. But for now, the 66-foot diameter hole serves a different purpose. It's what crews will use to lower the large tunnel boring machine more than 200 feet below the surface. The smaller working shaft is about 30 feet in diameter.
Short said City Utilities expects the working shaft will be done by the end of May, while the pump station shaft will probably be done in June, weather permitting.
“As soon as the shafts are done, we'll do a starter tunnel, which is done by hand, and also a tail tunnel,” Short said. “That will take almost a month also, so that will get done around the end of July.”
Drilling will start almost immediately after that.
The $188 million Three Rivers Protection and Overflow Reduction Tunnel is Fort Wayne's largest public improvement project and part of a 2008 consent decree with the U.S. Environmental Protection Agency. It will stretch five miles across the city from the Dwenger Avenue site to Foster Park. During heavy rain events, the tunnel will collect runoff and pump it to the water treatment plant to ease the strain on the city's combined sewer/stormwater system.
Once operational, the tunnel is expected to significantly reduce the number of sewer overflows into the city's rivers. The project is set to finish in 2021.