Emerging Coastal Network | Pacific Coast Watershed Partnership

Umpqua River Watershed | Umpqua 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 Umpqua Basin is one of the largest coastal river systems in Oregon, comprising almost 3 million acres (USDA Forest Service 2001). The North Fork rises in the High Cascade Mountains northeast of Diamond Lake. The South Fork rises in the western Cascade Mountains north east of the town of Tiller, Oregon (USDA Forest Service 1997). The two major forks join downstream of the city of Roseburg. The mouth of the Umpqua River is in the town of Reedsport, Oregon. The major salmonids in the basin include: Chinook (spring and fall, coho, steelhead (summer and winter), and cutthroat trout (resident, sea-run, and adfluvial). All salmonids are considered depressed except fall Chinook and resident cutthroat trout. The North Fork is internationally known for its salmonid fishing. The major factors responsible for the decline in freshwater rearing for the salmonids includes: logging and road building on steep slopes which increases the landslide/debris flow rates, harvesting riparian zones, large woody debris removal, and eutrophication originating from the impoundments on the upper North Fork (USDA Forest Service 2001).

The source of North Fork of the Umpqua River is Maidu Lake in the High Cascades. The bedrock geology in the headwaters is High Cascades Quaternary volcanic rock types (Walker and MacLeod 1991). The stream then passes through the Western Cascades geologic province dominated by the Little Butte Volcanic series. The Headwaters of the South Fork of the Umpqua River is in the western Cascades about 12 miles west of Diamond Lake. Almost the entire South Fork basin is dominated by the Western Cascades geologic province. The mainstem of the Umpqua river below Roseburg, flows through sandstones of Eocene age.

The precipitation pattern is complex as the river basin traverses the Coast Range and rises in the High Cascades (USDA Forest Service 2001). On the West slope of the Coast range annual precipitation averages over 100 inches on the ridge tops. On the east side of the Coast Range annual precipitation falls to about 50 inches. As the ridge tops rise again in the western Cascades and the High Cascades the annual precipitation rises to greater than 100 inches. Much of the western Cascades and High Cascades portion of the basin are in the rain on snow zone, which is between 2,000 and 5,000 feet in the basin.

Because of the differences in geology and precipitation, the stream flow and temperature regimes of the North and South Forks are significantly different (USDA Forest Service 1997 and 2002). The North Fork, which rises in the High Cascades, has a much higher summer base flow than the South Fork. The High Cascades lava flows are highly fractured and store a considerable volume of water Also, the High Cascades receives more snow providing melt water much later into the season than in the Western Cascades. Also, the temperature regime is much colder in the summer in the North Fork, largely because of the high volume of cold water flowing out of the bedrock.

There are two major vegetation communities found within the basin (Franklin and Dyrness 1973). In general, below 4,500 feet, the forest community is dominated by the western Hemlock community. The most conspicuous forest species in this area is Douglas fir. Above 4,500 feet, the forest communities are predominantly true fir, especially white and silver fir. In some of the drier portions of the basin, an Oak forest community is represented.

There are 4 species of salmonids found in the basin and a high diversity of life histories are observed: Chinook (spring and fall), coho, steelhead (summer and winter) and cutthroat trout (numerous life histories). All life histories are considered depressed except fall Chinook and resident cutthrout (USDA Forest Service 1997 and 2001). Fall Chinook rarely make their way into the upper portions of either the North or South Fork. The Spring Chinook population is considered stable but the number in both forks are low. By the 1940's commercial harvest was discontinued on Spring Chinook. Today, the total Spring Chinook population rarely approaches a 1,000 fish in the Umpqua river system. The steelhead populations are also considered depressed but stable. After high levels of harvest in the 1920's, steelhead have remained stable for the last 50 years. Steelhead angling in the North Umpqua attracts fishermen from all over the world.

On the other hand, coho salmon and cutthroat trout populations are depressed and declining (USDA Forest Service 1997 and 2001). Historically, the total coho run in the Umpqua river system approached 1 million fish in a strong year. During the 1940's and 50's, the adult coho run into the Umpqua River averaged about 1,800 fish. During the 1970's and 1980's it declined to an average of 400 fish. During recent years the average has increased a little to around 1,000 fish. Historical estimates of the cutthroat population in the Umpqua basin are lacking, but sea-run cutthroat have continued to decline since the 1950's. When the counts began for sea-run cutthroat in the 1950's at Winchester dam the average was about 950 fish annually. Today it is literally just a hand full, often less than 10 fish. Both coho salmon and cutthroat trout are listed under the Endangered Species Act (ESA). In addition, attention has been given to the Pacific Lamprey, which has also been declining since the 1970's.

The Western Cascades geologic province makes up the bulk of the basin is deeply weathered with steep slopes and V-shaped canyons. The soils have a high clay content and are prone to creep and landslides. Many of the streams have been degraded by: timber harvest and road building on steep unstable slopes, riparian timber harvest, and large woody debris removal (USDA Forest Service 1997 and 2001). In addition, on the North Fork, eutrophication from the upstream impoundments has been identified as a major water quality issue.

Literature Cited:

Franklin, J.F. and C.T. Dyrness.1973. Natural Vegetation of Oregon and Washington. Pacific Northwest Forest and Range Experiment Station. USDA Forest Service General Technical Report PNW-8.

USDA Forest Service. 1995. Dumont Creek Watershed Analysis

USDA Forest Service. 1997. Boulder/Ash Watershed Analysis

USDA Forest Service 1997b. Upper Steamboat Watershed Analysis

USDA Forest Service 1999. Lower Steamboat Creek. Watershed analysis.

USDA Forest Service. 2001. Watershed Analysis: North Umpqua River Wild and Scenic Corridor.

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