USGS Scientific Investigations Report 2010–5065Channel Change and Bed-Material Transport in the Lower Chetco River, Oregon

Table 1. Summary of reach attributes for the study area, Chetco River, Oregon.

[Abbreviations: m, meter; m/m, meter per meter; FPkm, flood-plain kilometer]

Reach name	Distance along floodplain axis (FPkm)	General description	Average water surface slope (2008)(m/m)	Average flood plain width(m)	Average width of low-flow channel (2008)(m)	Instream gravel extraction sites (1995–2008)
Upper	13.2–16	Steep, narrow channel corridor where channel and gravel bars have remained fairly stable over time.	0.00138	213	45	Fitzhugh Bar (FPkm 15.4), operated by Tidewater Contractors, Inc.
Emily Creek	10.6–13.2	Similar planform and stability as Upper Reach, but wider valley bottom and increasing bar size.	.00109	285	48	Tamba Bar (FPkm 11), operated by South Coast Lumber Co.
Mill Creek	7.6–10.6	Transition reach between the stable upper reaches and more dynamic North Fork Reach.	.00072	474	56	No extraction
North Fork	4.3–7.6	Historically most dynamic of all reaches. Extensive in-stream gravel mining at multiple sites since 1930s.	.00140	343	47	North Fork site  (FPkm 7–7.8), operated by Freeman Rock, Inc.
Estuary	0–4.3	Tidally influenced, confined between steep valley walls. Mouth of river historically was dynamic but navigation improvements have stablized channel entrance. Extensive gravel mining along multiple sites prior to 1990s.	.00015	329	96	Estuary Bar (FPkm 2.8), operated by Tidewater Contractors, Inc.