The Swan Lake Hydroelectric Project is a 22 MW hydroelectric facility with a concrete thin arch dam, intake, tunnel, penstock, and powerhouse located on Revillagigedo Island at the head of Carroll Inlet, approximately 22 miles northeast of the City of Ketchikan. The project is only accessible by floatplane or boat.
Pacific Pile and Marine was contracted to perform concrete demolition work on the spillway, procure and place Owner-designed embedded metals and seal plates for the flashboard system (a unique element to this project), erect the flashboard system, place Owner-provided embedded metals for the vertical gate and erect the vertical gate, place reinforced concrete on the wing walls, construct a new reinforced concrete center pier, and modify and seal existing parapet walls. PPM also made modifications to the intake building and constructed a utility trench and conduit bank that carries tubing and cabling from the intake building to the new vertical gate.
Highlights of the expansion include:
- Increasing the reservoir full-pool elevation 15 ft, providing about 25 to 30% more storage;
- Flashboards and a gate will be installed in the existing fixed spillway slot;
- Parapet wall reinforcement; and
- An increase in the height of water intake equipment.
