Preliminary Assessment of Channel Stability and Bed-Material Transport in the Coquille River Basin, Southwestern Oregon By Krista L. Jones, Jim E. O’Connor, Mackenzie K. Keith, Joseph F. Mangano, and J. Rose Wallick Prepared in cooperation with the U.S. Army Corps of Engineers and the Oregon Department of State Lands Open-File Report 2012–1064 U.S. Department of the Interior U.S. Geological Survey Cover: South Fork Coquille River in the Broadbent Reach (Photograph by Krista L. Jones, U.S. Geological Survey, July 2010.) Preliminary Assessment of Channel Stability and Bed-Material Transport in the Coquille River Basin, Southwestern Oregon By Krista L. Jones, Jim E. O’Connor, Mackenzie K. Keith, Joseph F. Mangano, and J. Rose Wallick Prepared in cooperation with the U.S. Army Corps of Engineers and the Oregon Department of State Lands Open-File Report 2012–1064 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior KEN SALAZAR, Secretary U.S. Geological Survey Marcia K. McNutt, Director U.S. Geological Survey, Reston, Virginia 2012 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1–888–ASK–USGS. 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Contents Figures ........................................................................................................................................................................... iv Tables ............................................................................................................................................................................ vi Conversion Factors ....................................................................................................................................................... vii Datums ......................................................................................................................................................................... vii Significant Findings ........................................................................................................................................................ 1 Introduction .................................................................................................................................................................... 3 Locations and Reporting Units ....................................................................................................................................... 5 The Coquille River ......................................................................................................................................................... 5 Geographic, Geologic, and Geomorphic Setting ........................................................................................................ 5 Hydrology ................................................................................................................................................................... 6 Historical Channel Descriptions ............................................................................................................................... 11 Occupation, Land Use, and Landscape Disturbance ............................................................................................... 13 Settlement and Ownership ................................................................................................................................... 13 Logging and Splash Damming .............................................................................................................................. 13 Dredging and Wood Removal for Navigation ........................................................................................................ 15 Instream Gravel Mining ........................................................................................................................................ 17 Mining ................................................................................................................................................................... 17 Fire ....................................................................................................................................................................... 17 Mass Movements ................................................................................................................................................. 18 Study Area ............................................................................................................................................................... 18 Powers Reach ...................................................................................................................................................... 21 Broadbent Reach .................................................................................................................................................. 21 Myrtle Point Reach ............................................................................................................................................... 24 Bandon Reach ...................................................................................................................................................... 24 Bridge Reach ........................................................................................................................................................ 24 Gravelford Reach ................................................................................................................................................. 28 Approach and Key Findings ......................................................................................................................................... 28 Review of Existing Datasets ..................................................................................................................................... 28 Aerial and Orthophotographs ................................................................................................................................ 28 Historical Maps and Survey Data ......................................................................................................................... 30 Previous Hydrologic and Geomorphic Studies ......................................................................................................... 34 Gravel-Operator Information and Surveys ................................................................................................................ 35 Bridge-Inspection Reports ........................................................................................................................................ 43 Specific Gage Analysis............................................................................................................................................. 52 Delineation of Bars and Channel Features, 1939–2009 ........................................................................................... 53 Distribution and Area of Bars, 2009 ...................................................................................................................... 56 Results for Repeat Channel Centerline and Width Delineations, 1939–2009 ....................................................... 58 iii Discussion of Changes in Bar and Channel Features, 1939–2009 ...................................................................... 61 Analyses of Bed-Material Particle Sizes ................................................................................................................... 71 Discussion and Synthesis ............................................................................................................................................ 73 Spatial Variation in Channel Conditions ................................................................................................................... 73 Temporal Trends in Channel and Bar Conditions .................................................................................................... 75 General Bed-material Transport Conditions ............................................................................................................. 75 Outstanding Issues and Possible Approaches ............................................................................................................. 76 Streamflow Data ......................................................................................................................................................