8.5x11 for PDF UPDATED Lower Wenatchee River REACH ASSESSMENT December 2017 Lower Wenatchee River Reach Assessment UPDATED Table of Contents 1. INTRODUCTION ............................................................................................................................................... 1 1.1 Purpose .......................................................................................................................................................... 3 1.2 Recovery Planning Context ........................................................................................................................... 3 1.3 Report Organization ...................................................................................................................................... 4 2. ASSESSMENT AREA CONDITIONS ................................................................................................................. 6 2.1 Setting and Climate ....................................................................................................................................... 6 2.2 Geology and Glacial History .......................................................................................................................... 7 2.3 Human History ............................................................................................................................................. 11 2.3.1 Early Settlement ................................................................................................................................. 11 2.3.2 Great Northern Railroad ..................................................................................................................... 12 2.3.3 Timber Harvesting .............................................................................................................................. 13 2.3.4 Wildfires .............................................................................................................................................. 14 2.3.5 Development and Agriculture ............................................................................................................ 14 2.3.6 Diversions and Dams ......................................................................................................................... 16 2.4 Water Quality and Quantity ......................................................................................................................... 17 2.5 Fish Use and Population Status ................................................................................................................. 19 2.5.1 Salmonids ........................................................................................................................................... 19 2.5.2 Non-Salmonid Species of Interest ..................................................................................................... 22 2.6 Ecological Concerns .................................................................................................................................... 22 3. REACH ASSESSMENT METHODS ................................................................................................................ 24 3.1 Topobathymetric LiDAR Data Collection .................................................................................................... 24 3.2 Geomorphic and Habitat Field Surveys ...................................................................................................... 24 3.3 Field Identification of Restoration Opportunities ....................................................................................... 25 3.4 Reach Assessment Analyses ...................................................................................................................... 26 3.4.1 Hydrology and Hydraulics ................................................................................................................... 26 3.4.2 Geomorphic Analyses ......................................................................................................................... 26 3.4.3 Canopy Height and Percent Cover ..................................................................................................... 27 3.5 Reach-based Ecosystem Indicators ........................................................................................................... 28 4. REACH ASSESSMENT RESULTS .................................................................................................................. 29 4.1 Topobathymetric LiDAR ............................................................................................................................... 29 4.2 Hydrology ..................................................................................................................................................... 30 4.3 Reach Descriptions ..................................................................................................................................... 33 4.4 Geomorphology ........................................................................................................................................... 48 4.4.1 Longitudinal Profile ............................................................................................................................ 49 4.4.2 Channel Migration .............................................................................................................................. 49 4.4.3 Floodplain Connectivity and Inundation ............................................................................................ 51 4.4.4 Sediment Characteristics and Flow Competence ............................................................................. 53 4.4.5 Large Woody Debris ........................................................................................................................... 56 4.4.6 Channel Units ..................................................................................................................................... 57 4.5 Riparian Vegetation ..................................................................................................................................... 59 4.6 Reach-based Ecosystem Indicators ........................................................................................................... 61 Yakama Nation Fisheries i Lower Wenatchee River Reach Assessment UPDATED 4.7 Climate Change Impacts ............................................................................................................................. 62 4.8 Reach Assessment Results Summary ....................................................................................................... 63 5. RESTORATION STRATEGY ............................................................................................................................ 65 5.1 Existing and Target Habitat Conditions ...................................................................................................... 65 5.2 Reach-Scale Restoration Strategies ........................................................................................................... 68 5.3 Project Opportunities and Potential Actions .............................................................................................. 70 5.3.1 Resource Preservation and Management ........................................................................................ 70 5.3.2 Instream and Floodplain Restoration ................................................................................................ 71 5.4 Project Prioritization and Scoring ............................................................................................................... 73 5.5 Restoration Strategy Summary ................................................................................................................... 75 6. CONCLUSION AND NEXT STEPS .................................................................................................................. 76 7. REFERENCES ................................................................................................................................................ 78 Appendix A: Index of Existing Reach Assessment Data (provided on DVD) Appendix B: Lower Wenatchee River Topobathymetric LiDAR Technical Data Report Appendix C: Stream Habitat and Geomorphic Map Series River Mile 0.0 to 26.4 Appendix D: Reach-Based Ecosystem Indicators Appendix E: Potential Project Opportunities Appendix F: Project Opportunities Geodatabase (provided on DVD) Appendix G: Project Opportunities Prioritization Matrix (provided on DVD) Tables Table 2-1. Periodicity Table for Spring Chinook, Summer Steelhead, and Columbia River Bull Trout in the Lower Wenatchee River ................................................................................................................. 21 Table 3-1. Stream Habitat Field Data Collection Description .............................................................................. 25 Table 4-1. Peak Discharges for the 2-Year, 10-Year, 50-Year, and 100-Year Flood Events ............................. 32 Table 4-2. Geomorphic Reach 1 Location and Existing Characteristics ............................................................. 38 Table 4-3. Geomorphic Reach 2 Location and Existing Characteristics ............................................................. 39 Table 4-4. Geomorphic Reach 3 Location and Existing Characteristics ............................................................