HUMPBACK CREEK INTAKE/DIVERSION REHABILITATION PROJECT

摘要

Cordova Electric Cooperative’s Humpback Creek Hydroelectric Facility is located near the east shore of Orca Inlet in South Central Alaska. The project was constructed on Humpback Creek as a modern facility in 1991 and has operated until November 2005 when the powerhouse was damaged by a fire. As repairs to the powerhouse neared completion flows generated by a massive rainstorm in October 2006 damaged and destroyed key project features including the intake/diversion and the upper conveyance flume. Planning for project rehabilitation commenced immediately following the flood in 2006 and a project team was established by Cordova Electric Cooperative (CEC) under R&M that included Hatch, and MBA as the consulting engineers for the project design and construction and environmental assessment for CEC’s final application for a non-capacity amendment to their FERC license. The project rehabilitation was successfully completed and the project back on line in July, 2011. Challenges included design for a remote project with no road access, a creek with challenging hydraulic and geotechnical conditions subject to substantial bed load movement and rapid change in creek flow rates. CEC’s R&M/Hatch project team methodically reviewed the project’s operating history and developed the rehabilitation design based on a review and evaluation of alternative project arrangements. Careful planning, design and construction management by CEC and the consulting team have resulted in a rehabilitated project that has proved to be exceptionally reliable during its first year of operation. Numerous design/construction challenges were addressed through innovation and attention to details.