Estimated construction cost is in the range of £70m to £100m.
The 4.5m-diameter tunnel will convey combined sewer flows and provide storm storage in both the tunnel and shafts.
Depth of the tunnel has yet to be determined. A higher alignment based on gravity and a lower alignment coupled with a lift pump station are both being considered. In either case, underground mine workings along the route will impact upon either route option.
The project is expected to take seven years to complete.
For more details, see our Contract Leads section.