The Jacobs Associates-Wade Trim Joint Venture provided final design and construction administration services for the Doan Valley Tunnel (DVT) system. With a storage volume of 18 MG, the tunnel system provides relief to the existing interceptor by reducing overflows and providing additional capacity to alleviate basement flooding. The tunnel system discharges CSO control flows up to 50 MGD via a downstream modulating gate during wet weather events. This controlled release of flows during a storm event maximizes available downstream conveyance capacity and dramatically reduced the required size of the DVT storage tunnel.

The DVT system features 19,300 feet of tunnel in rock. Major components include the DVT tunnel (18-foot-diameter, 10,000 LF), Woodhill Conveyance Tunnel (8.5-foot-diameter, 6,300 LF), and the MLK Conveyance Tunnel (8.5-foot-diameter, 3,000 LF). The system includes five drop shafts, six diversion structures, an overflow structure for normal operations and an emergency overflow pipeline and connection structure.

A flow monitoring program and extensive hydraulic modeling were conducted to calibrate the model and support design activities. Modeling confirmed CSO compliance and collection system flooding protection. Mixed-interface transient modeling was performed to account for the dynamic filling nature of the tunnels and to develop operational protocols to protect the tunnel system during large storm events.

Awards
ACEC National Honor Award, 2022
ACEC Ohio Outstanding Achievement Award, 2022