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Three Rivers Protection & Overflow Reduction Tunnel, IN

Fort Wayne discharges a large amount of diluted sewage into nearby rivers every year. The tunnel is a major portion of the effort to clean up Fort Wayne’s rivers and protect neighborhoods from basement backups and street flooding.

90%
Reduction in combined sewer overflows discharging untreated water to the Fort Wayne Rivers
100
Years Constructed Life Span
5
Miles of Tunnel Construction

Overview

Tunnel Works, a large tunnel and network of pipes in the bedrock below the city, was designed by Fort Wayne City Utilities to collect and transport sewage from the combined sewer system to the sewage treatment plant. Tunnel Works is the City’s main project for reducing the amount of diluted sewage discharged into the rivers.

The 3RPORT project included consolidation sewers, 9 drop shafts, and a deep rock tunnel to collect and convey combined sewer overflows (CSOs) from 22 outfalls along the St. Mary’s and Maumee Rivers. The tunnel’s life expectancy is 100 years.

Technical Highlights

  • The tunnel depth is 200 to 250 feet below the ground surface. It is a segmentally lined tunnel.
  • The project reduces the number of CSOs into the rivers by 90%―or more than 850 billion gallons on average each year―which occur during large rainstorms.
  • Approximately 16,600 feet of near surface consolidation and relief sewers that convey CSOs from diversion structures to drop shafts.

BENEFITS/POSITIVE IMPACT TO COMMUNITY

The deep-rock tunnel is a major part of the effort to:

  • Clean up Fort Wayne’s rivers
  • Protect neighborhoods from basement backups and street flooding
  • Improve quality of life and the environment