Ashton Dam Remediation Phase I
- Owner: PacifiCorp
- Location: Ashton, ID
- Contract Value: $6 M
- Core Competencies: Earthwork, Structural Concrete
This project required the construction of a diversion tunnel through bedrock of an abutment; serving as a river diversion during rehabilitation of an existing earth dam. The tunnel was constructed using drill and blast methods, including lining with rock bolts, mesh and shotcrete. The tunnel entrance was connected to a reinforced concrete control structure with a dual gate control system that includes both 90-inch x 180-inch slide gates and bulkhead gates. A “lake tap” was implemented by excavating an inlet channel to direct reservoir water to the control structure and diversion tunnel.