Table 3. Geomorphic and channel characteristics for reaches in the Umpqua River basin, Oregon.

[Abbreviations: FPKM, flood-plain kilometer; km², square kilometer; m, meter; m², square meter, m²/m, meter squared per meter; m³/s, cubic meter per second]

Attribute	Reach
	Tidal	Coast Range	Garden Valley	Roseburg	Days Creek	North Umpqua
Position	FPKM 0–40	FPKM 40–152	FPKM 152–168.5	FPKM 168.5–231	FPKM 231–274.5	FPKM 0–44.5
Reach definition	Tidally affected	Confined valley, bedrock channel	Unconfined below North and South Umpqua River confluence	Cow Creek confluence to North Umpqua River confluence	Downstream of Jackson Creek confluence to Cow Creek confluence	Little River confluence to South Umpqua River confluence
General valley setting	Estuary, confined valley opening to bay within coastal plain	Confined valley with local valley widenings	Unconfined	Alternating confined and unconfined	Alternating confined and unconfined	Alternating confined and unconfined
General channel character	Low gradient, sand and gravel bed	Steep, bedrock rapids separated by flats	Alternating bedrock and gravel	Alternating bedrock and gravel	Alternating bedrock and gravel	Bedrock dominant, pool and drop
Drainage area at downstream end of segment (km2)	12,102	10,492	8,904	4,666	1,962	3,522
Drainage area at upstream end of segment (km2)	10,492	8,904	8,188	3,254	1,127	3,151
Average gradient	0.00012	0.00073	0.00098	0.00100	0.00249	0.00177
Unit bar area 2005 (m2/m)1	114.5	5.1	5.0	13.6	17.6	6.7
Total area of gravel bars in 2005 (m2)	3,837,380	593,360	93,093	1,030,751	835,873	317,358
Total area of bedrock in 2005 (m2)	1,337	3,122,615	266,223	488,550	146,882	1,213,280
Total area of channel (secondary channel features) in 2005 (m2)	16,576,148 (346,575)	11,672,878 (170,575)	1,668,568 (1,848)	4,297,485 (73,742)	1,536,393 (37,687)	3,358,262 (86,977)
0.5 annual exceedance probability discharge (m3/s)2	32,660	32,660	32,660	41,292	5481	61,256
Figures showing channel morphology	1, 6, 33	1, 2, 7, 16, 22, 23	1, 2, 8	1, 2, 9, 16, 22, 23	1, 2, 10, 16, 22, 23	1, 2, 11, 16, 28

¹2005 mapped bar area divided by reach centerline.

²Following Bulletin 17-B guidelines for gage record through water year 2008.

³U.S. Geological Survey streamflow-gaging station on Umpqua River at Elkton.

⁴U.S. Geological Survey streamflow-gaging station on South Umpqua River near Brockway.

⁵U.S. Geological Survey streamflow-gaging station on South Umpqua River at Tiller.

⁶U.S. Geological Survey streamflow-gaging station on North Umpqua River at Winchester.

First posted September 29, 2011