Author(s): Hans Arnett; D. Lance Mearig; Shane Cherry

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Abstract: Maintaining a sustainable environment while advancing a capital project program requires effective mitigation of unavoidable impacts to sensitive resources. In 2007, the Alaska Department of Transportation and Public Facilities initiated the construction of safety upgrades at the Ketchikan International Airport including extending the runway safety area at the south end of the runway. The expanded runway safety area extended over the pre-existing natural alignment of Government Creek. The stream supports multiple anadromous and resident salmonid species. After considering multiple options during the environmental permitting process, it was determined that realignment and construction of a new stream channel would most effectively sustain ecological function of the stream and estuary associated with Government Creek. A new channel was constructed within a newly excavated bedrock canyon to the southeast, and a portion of the historic stream valley and channel were filled to accommodate the runway safety area extension. The channel design was developed by characterizing the geomorphology of a reference reach selected to represent the natural channel located upstream. Stream flow was diverted into the new channel on August 15,2007. Early monitoring data demonstrated that both juvenile and adult salmon occupied and used the new habitat within two weeks of the diversion.

DOI:

Year: 2009