Bonanza Area Reach Assessment Yankee Fork of the Salmon River, Upper Salmon Subbasin
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Bonanza Area Reach Assessment Yankee Fork of the Salmon River, Upper Salmon Subbasin Custer County, Idaho U.S. Department of the Interior Bureau of Reclamation Pacific Northwest Region Pacific Northwest Regional Office, Boise, Idaho September 2012 U.S. DEPARTMENT OF THE INTERIOR The Department of the Interior protects and manages the Nation’s natural resources and cultural heritage; provides scientific and other information about those resources; and honors its trust responsibilities or special commitments to American Indians, Alaska Natives, and affiliated island communities. MISSION OF THE BUREAU OF RECLAMATION The mission of the Bureau of Reclamation is to manage, develop, and protect water and related resources in an environmentally and economically sound manner in the interest of the American public. Cover Photo: View to the west looking upstream along the West Fork (upper channel) and Yankee Fork (lower channel), and their historic confluence area (upper right) – Bureau of Reclamation Date: September 2, 2010 Photo by: David Walsh Bonanza Reach Assessment Yankee Fork of the Salmon River, Upper Salmon Subbasin Custer County, Idaho U.S. Department of the Interior Bureau of Reclamation Pacific Northwest Region Pacific Northwest Regional Office, Boise, Idaho September 2012 This page intentionally left blank Acronyms and Abbreviations BiOp Biological Opinion cfs cubic feet per second FCRPS Federal Columbia River Power System GIS geographic information system Hecla Hecla Mining Company HUC hydrologic unit code LiDAR light detection and ranging 2 mi square miles 2 mi/mi miles per square mile mm millimeter Reclamation Bureau of Reclamation REI reach-scale ecosystem indicators RM river mile RPA Reasonable and Prudent Alternative Tribes Shoshone Bannock Tribes Tributary Assessment Yankee Fork of the Salmon River Tributary Assessment TWA total wetted area USFS U.S. Forest Service West Fork West Fork of the Yankee Fork Salmon River Yankee Fork Yankee Fork of the Salmon River September 2012 This page intentionally left blank Table of Contents Acknowledgements ................................................................................................................... 1 Executive Summary ................................................................................................................. 1 Introduction ............................................................................................................................ 5 Purpose of this Reach Assessment ................................................................................. 6 Reach Assessment Philosophy ....................................................................................... 6 Reach Assessment Goals................................................................................................ 9 Using this Document ...................................................................................................... 9 Assessment Methods ...................................................................................................... 9 Background Information .............................................................................................. 10 Limiting and Causal Factors ........................................................................................ 13 Summary of Existing Reports ...................................................................................... 13 Regional Setting ............................................................................................... 14 Yankee Fork Watershed Physical Characteristics and Condition .................... 14 Yankee Fork Watershed Fish Usage and Density ............................................ 16 Salmon and Steelhead Usage ........................................................................... 16 Chinook Salmon Fish Density ......................................................................... 17 Lower Yankee Fork and West Fork Subwatersheds ........................................ 19 Lower Yankee Fork Subwatershed .................................................................. 19 West Fork Subwatershed.................................................................................. 19 Historical Timeline....................................................................................................... 20 Historic and Existing Conditions Comparison ............................................................. 26 Historical Conditions ............................................................................................................. 27 Yankee Fork ................................................................................................................. 28 West Fork ..................................................................................................................... 34 Existing Conditions ................................................................................................................ 37 Yankee Fork ................................................................................................................. 38 Channel Reach Characteristics ......................................................................... 38 Bedforms and floodplain characteristics .......................................................... 41 Vegetation Condition ....................................................................................... 43 Floodplain Connectivity ................................................................................... 45 West Fork ..................................................................................................................... 47 Channel Characteristics .................................................................................... 47 Bedforms and Floodplain Characteristics ........................................................ 50 September 2012 i Table of Contents Vegetation Condition ....................................................................................... 52 Floodplain Connectivity ................................................................................... 52 Degree of Impairment ............................................................................................................ 55 Yankee Fork ................................................................................................................. 55 West Fork ..................................................................................................................... 59 Target Conditions .................................................................................................................. 62 Yankee Fork ................................................................................................................. 63 West Fork ..................................................................................................................... 65 Potential Habitat Actions ...................................................................................................... 68 Yankee Fork ................................................................................................................. 68 West Fork ..................................................................................................................... 74 Summary .......................................................................................................................... 76 Next Steps .......................................................................................................................... 78 List of Preparers ..................................................................................................................... 79 Literature Cited ...................................................................................................................... 81 Glossary .......................................................................................................................... 87 Appendix A – Reach-based Ecosystem Indicators Appendix B – Reach Assessment Analysis Appendix C – Photographic Documentation Appendix D – GIS Databases List of Figures Figure 1. Flow chart illustrating typical steps in the approach to habitat improvement. .......... 6 Figure 2. Yankee Fork subwatershed locations. ....................................................................... 8 Figure 3. Bonanza Area Reach Assessment location. ............................................................. 12 Figure 4. Yankee Fork stratified snorkel survey samples from 1984 to 2009 by subwatershed based on data collected by the Tribes. ......................................................... 18 Figure 5. Yankee Fork redd counts by subwatershed based on data collected by the Tribes.................................................................................................................................. 18 Figure 6. General Custer Mill 1937 located along the Yankee Fork upstream of Custer. ................................................................................................................................ 22 ii September 2012 Table of Contents Figure 7. Yankee Fork Gold Dredge working between Rankin Creek and Jerrys Creek in 1945................................................................................................................................ 23 Figure 8. U.S. Antimony Corporation’s vat leach cyanide mill at Preachers Cove in 1991...................................................................................................................................