This project will replace an undersized, deteriorated culvert that impedes adult and juvenile fish passage and limits stream function. When constructed, the project will restore access to 1.6 miles of spawning and rearing habitat on Illingsworth Creek. Anadromous salmonid fish species occurring in Illingsworth Creek include, spring and fall Chinook salmon, coho salmon, and chum salmon, summer and winter steelhead, and sea-run cutthroat trout. Resident cutthroat trout are also present. Resident Pacific lamprey likely occur in the watershed but are not well-documented.
Illingsworth Creek is utilized by juvenile salmon for summer and winter rearing and has been determined to be one of the four most important tributary habitats in the Miami Basin for coho salmon production. In 2007, average coho rearing densities for the Miami were the highest on Illingsworth Creek. ODFW identifies Illingsworth Creek and the Miami River as High Intrinsic Potential, providing essential low gradient coho rearing habitat.
Historically chum salmon were found in 13 basins along the Oregon Coast. Today only eight basins still have populations of chum. Within the Tillamook Bay basin, the Miami subbasin is one of three primary spawning areas for chum. Chum fry are known to reside in marshes along tidal creeks, such as Illingsworth, at low tide the fry retreat up into these creeks for refuge and forage.
In addition to salmonids, a healthy beaver population occupies Illingsworth Creek enhancing habitat for juvenile salmon rearing. Amongst the beaver habitat, there is approximately one mile of upstream spawning area with abundant spawning gravel and well scoured pools.
