Siebert Creek is an independent drainage with 31.2 miles of mainstem stream and tributaries, and headwaters located in Olympic National Park. The creek is 12.4 miles long, and drains 19.5 square miles of the northwest flank of Blue Mountain, with the upper reaches typically steep and incised at elevations up to 3,800 feet. The lower reaches contain both moderate and low-gradient habitat. Land uses include commercial forestry, Olympic National Park, private woodlots, pastures or grasslands, and increasing levels of residential development. Siebert Creek is the westernmost stream influenced directly by irrigation flows from the Dungeness River, and was closed in 1973 to new surface water appropriation. A recent volunteer group made up of watershed residents and others brought much-needed attention to the habitat needs of Siebert Creek, and was very active in restoration, education and watershed planning.
Siebert Creek historically supported coho and chum salmon, steelhead, cutthroat and rainbow trout and Dolly Varden have been documented there (probably using it for foraging and/or over wintering habitat). The mainstem and tributaries currently support coho salmon, winter steelhead and cutthroat trout. The stream has been characterized in the Limiting Factors Analysis as having ideal fish habitat throughout, except in the East Fork. A few eroding stream banks have been noted in the lower section, immediately downstream of HWY 101, meaning excessive sediment is entering the creek, which may limit spawning and food gathering success for fish. Healthy ratings for water temperatures and dissolved oxygen mean that the water quality conditions for fish are good, while the compromised biological integrity, indicates that some changes are occurring that may impact conditions for fish.
- State of the Waters of Clallam County 2004