February 5, 2021

Best in State: Gold award — Unique or Innovative Applications
Parr Excellence

Photo courtesy of ACEC

Habitat restoration of Sarah Creek included creating a roughened channel fishway.

Project: Sarah Creek habitat restoration
Client: Cowlitz Indian Tribe

Washington’s natural salmon runs are critical to the health of the Puget Sound ecosystem, as well as to the sustenance of the Cowlitz Indian Tribe. The Sarah Creek habitat enhancement is one of 10 projects that have been implemented by the tribe in the Abernathy Creek Watershed, which is part of the Lower Columbia Intensively Monitored Watershed.

A unique combination of stream restoration approaches was the ultimate solution to overcome many site and regulatory barriers to transform this section of Sarah Creek from a fish barrier to nurturing fish habitat. The project included an innovative application of boulder ballast for large wood structures placed over bedrock.

This project’s fish passage design included creating a roughened channel fishway in the reach downstream of a 7-foot-high bedrock waterfall located approximately 300 feet upstream of its confluence with Abernathy Creek and a 600-foot-long sheet of bedrock that formed the stream bed upstream of the waterfall. The waterfall and supercritical flows through the upstream bedrock reach impeded coho salmon passage.

The project combined both currently accepted philosophies — the prescriptive and the process-based approaches — to create a successful result.

The prescriptive philosophy would address a general lack of pools in a stream by excavating pools as a solution. Creating artificial pools this way is problematic if sediment transport is not well understood. In some locations, the pools would simply fill in during the next flood event.

Providing fish passage access to high-quality habitat has been shown to be one of the most effective restoration strategies. The newly formed roughened channel has three pools for resting areas and backwaters to enhance passage into the upstream reach.

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