USGS Scientific Investigations Report 2011–5041 - Channel Change and Bed-Material Transport in the Umpqua River Basin, Oregon

Table 4. Channel trends and anthropogenic impacts for reaches in the Umpqua River basin, Oregon.

[Abbreviations: FPKM, flood-plain kilometer; mi², square mile]

Attribute	Reach
Attribute	Tidal	Coast Range	Garden Valley	Roseburg	Days Creek	North Umpqua
Major flow factors	Tidally affected	Minimal regulation	Minimal regulation	Galesville Reservoir, Oct. 7, 1985, regulates 74.3 mi² of Cow Creek basin (5.9 percent of contributing area at upper end of segment)	None	Pacific Power dams constructed 1952–1955 regulate (slightly) drainage from 430 mi² (35 percent of the upper end of segment)
Major sedimentation factors	Gradient change promotes deposition of sediment load; Smith River sediment inputs; dredging (100,000–500,000 cubic yards per year)	Sediment input from tributaries; local landuse and forest practices	Local sand and gravel mining; forest practices; Calapooya Creek sediment input	Late 19th century placer mining in reach and tributaries; forest practices; sand and gravel mining; tributary sediment inputs	Forest practices; sand and gravel mining; tributary sediment inputs	Pacific Power dams trap upstream sediment; forest practices
Channel disturbance factors	Historic navigation dredging, sand and gravel mining, rock removal for navigation near Scottsburg; road corridor	Late 19th century navigation improvements; temporary mill dam at Kellogg (removed 1871); road corridor	Late 19th century navigation improvements; sand and gravel mining	Local navigation improvements; transportation infrastructure; log driving; 19th century mill dams; sand and gravel mining; placer mining	Transportation infrastructure; log driving (?); sand and gravel mining; placer mining	Navigation improvement; log driving; Winchester Dam at FPKM 10.2
General channel trends	Some evidence of local incision historically near gravel mining operations (CH2M Hill, 1972)	Channel historically and presently on bedrock; little or no evident change (photos, specific gage analysis for Elkton gage)	Channel historically and presently on bedrock. No obvious change evident from inspection of aerial and oblique photographs, analysis of bar area	Channel historically and presently on bedrock. No obvious change evident from inspection of aerial and oblique photographs, analysis of bar area, and specfic gage analysis	Channel locally on bedrock. No evident trends, although limited data for this reach	Channel historically and presently on bedrock. No evident change from specific gage analysis