Allison Creek flows from Allison lake adjacent to the Valdez Marine Terminal near Valdez, Alaska. It is an anadromous fish stream flowing into Port Valdez. A 40’ wide in-stream concrete dam was installed in 1976 in association with a raw water intake structure in the stream bed. By 2003, the bed elevation downstream of the dam had lowered sufficiently that the dam was undermined and the stream breached under the dam. This project involved removal of the concrete dam and restoration of the stream through the site to provide unimpeded fish passage and protect the water intake system. The channel was re-constructed as a step-pool channel system to distribute a drop of approximately 11 feet over a distance of 280 lf. The design was based [...]
