Humpback Creek Hydroelectric Project for Cordova Electric Cooperative

General: The primary project features include a dam diversion structure that ponds water at 174 feet elevation above the power plant floor and develops a 12 foot deep pond of water that reaches approximately 500 feet upstream. A tunnel-and-pipeline power conduit conveys water 1,900 feet to a power house. A 17,000 foot underground and submarine transmission line delivers power from the project located 7 miles up coast from Cordova to a landing near Orca Adventure Lodge at the northern limit of the Cordova road system.

Diversion Dam and Intake Structure: The diversion dam is a 35 foot high concrete structure from bedrock to top. The dam features a 10 foot stop-log bay, a 3 ton jib crane, and a 10 foot x 10 foot Obermeyer gate for passing gravel and debris during high flows. A 3 foot x 8 foot sluice gate exterior to the trash racks sluices gravel and leafy-woody debris downstream, while an interior 2 foot x 2 foot sluice gate passes sand and debris downstream and away from the 7 foot x 7 foot penstock inlet gate. The intake features remote control lighting and video cameras. A concrete control building houses the electrical and mechanical equipment that operates the gates, SCADA, and tunnel ventilation. The plant is remotely operable over secure fiber optic communications.

Powerhouse: The Powerhouse contains two 500 kW Francis turbines and one 250 kW Turgo turbine rated for 76 psi water pressure. A concrete tailrace returns water to Humpback Creek upstream of the pink salmon spawning beds.

Share this Post: