Emerging Coastal Network | Pacific Coast Watershed Partnership

Coquille River Watershed | Rogue - Siskiyou National Forest


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	Skagit Dungeness Lower Columbia Siuslaw Umpqua Coquille


	6th field HUC Maps:

	Skagit Dungeness Lower Columbia Siuslaw Umpqua Coquille

The Coquille basin drains about 1032 square miles of the Coast Range along the south-central Oregon coast. There are three major forks: North Fork, Middle Fork and South Fork. The mouth of the river is located at Bandon, Oregon. The South Fork of the Coquille was selected as part of the Pacific Demonstration Project. The South Fork included in the project and assessment comprises about 145 square miles. The geology of the basin is complex. Part of the basin is Eocene sandstone formations; the other portion is in the Klamath Province. The salmonids found in the Coquille include: Chinook, coho salmon, steelhead, and cutthroat trout. The Coquille was (along with the Siuslaw) one of the most important coho producing stream on the Oregon Coast. Today coho salmon, spring Chinook, steelhead, sea-run cutthroat populations are depressed. Only the fall Chinook salmon population is considered healthy.

The Coquille drains about 1,000 square miles of the south-central Oregon Coast Range (USDA Forest Service 1996). There are three major forks: North, Middle, and South Fork. The mouth of the Coquille is near the town of Bandon. The South Fork of the Coquille River was selected as one of the Pacific Demonstration Projects by the Rogue-Siskiyou National Forest. The South Fork included in the project and assessment comprises about 145 square miles. Within the key watershed portion of the basin, 69% of the basin is classed as late-successional reserve (LSR), 20% matrix, and 7% riparian.

Most of the surface geology of the Coquille is Eocene sedimentary formations (Walker and MacLeod 1991). Most of these formations are sandstone; however, the Looking glass formation is conglomerate at the bottom and transitions to sandstone on the top. In the South Fork Coquille there are considerable pre-Tertiary strata that form the Klamath Mountain Province. The bedrock geology of the South Fork is highly complex. The Middle Fork of the Coquille is usually considered the boundary between the Coast Range and the Klamath Mountain geologic Province. The various bedrock types all have naturally high sedimentation rates.

The majority of the watershed is forested (USDA Forest Service 1996). The coniferous forests on productive soils and slopes in the basin are predominantly Douglas-fir. Port Orford Cedar (Chamaecyparis lawsoniana) is also an important component of the forests. In the lowlands the forest communities are oak savannahs on the drier sites and Douglas fir, cedar, and hemlock on the wetter sites. Historically, the fire interval in the western hemlock zone is about 65 years. The average stand age was about 280 years.

The major salmonids found in the basin include: Chinook, coho, steelhead and cutthroat trout. A few spring Chinook are found in the Coquille system, as well as the more numerous fall Chinook. The spring Chinook run is highly depressed due to high summer stream temperatures, sedimentation and poaching (USDA Forest Service 1996). The fall Chinook run is healthy. At the beginning of the 1900's the Coquille had one of the largest coho salmon runs on the Oregon Coast. Now coho as well as steelhead trout and cutthroat trout populations are considered depressed. The resident rainbow and cutthroat populations are considered stable.

The European settlement of the basin began in the 1850's with the arrival of miners and settlers. In 1915 a railroad was constructed which linked the South Fork area with Coos Bay. This railroad system enabled logs to be shipped to the coast as well as materials and supplies to be brought to Powers. Many families in the area are sixth generation. However, when timber harvest levels dropped from 19 million board feet/ year in the 1980's to 4 million board feet/year during the 1990's, the populations of the Powers area decreased by approximately 17% (USDA Forest Service 1996).

There are a number of factors responsible for the decline in the salmonids habitat in the South Fork of the Coquille (USDA Forest Service 1996). Starting in the 1850's, the lowlands were settled and considerable wetlands were diked and drained. In the 1950's after World War II, road building and logging on steep slopes accelerated sedimentation into streams. During the 1980's an average of 19 million board feet of timber per year was harvested from the Powers Ranger District. Also, logging has changed riparian forests and forests on steep slopes from late to early serial stage. This has resulted in a significant loss of large wood from the stream systems. To further exacerbate this problem during the 1960's and 1970's much stream cleaning occurred which removed large numbers of jams out of the stream systems. Since the 1990's logging has declined especially on steep slopes resulting in a decrease in sediment reaching the South Fork streams. It is anticipated that sedimentation rates will decline in the next few decades and the riparian forests and forests on steep slopes will move to later serial stages. This will increase the rate accumulation of large wood into the stream systems creating better fish habitat.

Literature Cited:

U.S.D.A. Forest Service. 1996. Watershed Analysis of the South Fork of the Coquille River.

Walker, G.W. and N.S. MacLeod. 1991. Geologic Map of Oregon. U.S. Dept. of Interior. Geologic Survey.