North Creek drains into the Sammamish River and several areas along the stream have been restored with the purpose of restoring salmon spawning habitat. Our survey included mapping valuable spawning areas by documenting where pools, riffles, and glides were located. We also measured creek width, depth, and stream surface velocity. My research partners and I studied under Dr. Jeff Jensen at UW Bothell.
North Creek continues to sustain juvenile and spawning populations of salmonids, including sockeye salmon (Oncorhynchus nerka), coho salmon (O. kisutch), and chinook salmon (O. tshawytscha). Puget Sound chinook, which spawn in North Creek, are a federally recognized Evolutionarily Significant Unit (ESU) listed as threatened under the Endangered Species Act (originally listed in 2005; updated 2014). With the restoration of the North Creek UWB/CCC Wetlands beginning in 1998, habitat quality in the lower section of North Creek has dramatically improved for both juvenile and returning adult salmon. Sockeye salmon have been observed spawning within the wetland, and adult chinook are regularly present. North Creek was last surveyed by King County in 1993.
Pools are important for salmonid habitat which provide juvenile salmonids a slow-moving place to shelter with a constant food supply moving through with the current. Pools also provide spawning salmonids a place to rest on the way up, and non-migratory adult salmonids a deep place to reside.
To assess changes in salmonid pool habitat quality, we will replicate King County’s 1999 Habitat Survey methods for stream assessment, including collecting data to calculate the Pool Quality Index (PQI).
The PQI assesses a variety of relevant stream attributes such as the depth of pools and vegetative cover. This data, as well as other creek features, will contribute to the overall Habitat Quality Index (HQI) which includes pools, riffles, glides, and presence of large woody debris. The HQI is the long term goal which will be addressed in future research.