CHAPTER 7: CHELAN RIVER BIOLOGICAL EVALUATION AND IMPLEMENTATION PLAN Chelan River Biological Evaluation and Implementation Plan TABLE OF CONTENTS CHAPTER 7: CHELAN RIVER BIOLOGICAL EVALUATION AND IMPLEMENTATION PLAN ...........................................................................................................................7-1 EXECUTIVE SUMMARY ............................................................................................. 7-1 SECTION 1: Introduction ................................................................................................................................. 7-6 SECTION 2: Background .................................................................................................................................. 7-8 2.1 Current Operations ......................................................................................................................................7-8 2.2 Lake Chelan - Water Quality.....................................................................................................................7-10 2.3 Lake Chelan – Lake Levels.......................................................................................................................7-11 2.4 Lake Chelan – Recreation .........................................................................................................................7-12 2.5 Chelan River – Recreation ........................................................................................................................7-12 2.6 Chelan River Biological Evaluation and Implementation Plan.................................................................7-12 2.6.1 Instream Flow Incremental Methodology (IFIM) .............................................................................7-12 2.6.2 Limiting Factors ................................................................................................................................7-13 2.6.3 Barrier Analysis.................................................................................................................................7-15 2.6.4 Considerations and Investigations of the Working Group.................................................................7-15 2.6.5 Working Group Flow Proposal .........................................................................................................7-18 2.7 Discussion of Temperature Relationships in the Chelan River .................................................................7-19 2.7.1 Chelan River Thermodynamics – Site Potential................................................................................7-20 2.7.2 Other Major Influences .....................................................................................................................7-25 2.7.3 Temperature Modeling ......................................................................................................................7-26 2.8 Review of Biological Objectives and Site Limitations .............................................................................7-28 SECTION 3: Management Considerations and Options Investigated......................................................... 7-30 3.1 Habitat and Flow Options Considered ......................................................................................................7-30 3.1.1 Sub-reach 4.1.....................................................................................................................................7-30 3.1.2 Sub-reach 4.2.....................................................................................................................................7-30 3.1.3 Sub-reach 4.3.....................................................................................................................................7-31 3.1.4 Sub-reach 4.4.....................................................................................................................................7-31 3.2 Habitat Modifications in the Tailrace........................................................................................................7-33 3.3 Water Temperature - Options Considered.................................................................................................7-36 3.3.1 Temperature Effects of Powerhouse Diversion.................................................................................7-36 3.3.2 Stream Channel Modification - Thalweg Formation.........................................................................7-38 3.3.3 Minimum Flow Diversion Structure..................................................................................................7-40 3.3.4 Site Potential Shade...........................................................................................................................7-40 3.3.5 Cutthroat Habitat and Potential Thermal Refugia in Reaches 1-3.....................................................7-41 3.3.6 Pumping of Tailrace Water into Reach 4 ..........................................................................................7-41 Tailwater................................................................................................................................................7-41 Comprehensive Plan Lake Chelan Project No. 637 October 8, 2003 Page 7-i SS/7933 Chelan River Biological Evaluation and Implementation Plan Pumping from Columbia River - Feasibility Analysis ..........................................................................7-42 3.3.7 Increase Flow During Daytime .........................................................................................................7-42 3.3.8 Other Options Considered to Improve Temperature Conditions.......................................................7-43 Providing Project Inflow During Summer Months – Feasibility Analysis ............................................7-44 Pipeline to Lake Chelan Thermocline - Feasibility Analysis ................................................................7-45 Ground Water Pumping for Upper Reaches - Feasibility Analysis .......................................................7-45 3.4 Riparian Vegetation - Limited Opportunities............................................................................................7-46 3.5 Macroinvertebrate Community - Limiting Factors ...................................................................................7-46 3.6 Summary of Management Options............................................................................................................7-47 SECTION 4: Achievement of biological objectives........................................................................................ 7-51 4.1 Functional Aquatic Ecosystem..................................................................................................................7-51 4.1.1 Macroinvertebrate Community .........................................................................................................7-57 4.1.2 Fish Community - Reaches 1-3 .........................................................................................................7-57 Native Cool Water Species....................................................................................................................7-57 Cutthroat................................................................................................................................................7-58 4.1.3 Fish Community - Reach 4 and Tailrace...........................................................................................7-59 Salmon and steelhead Spawning Habitat...............................................................................................7-59 Redd Protection .....................................................................................................................................7-59 Prevent Dewatering...........................................................................................................................7-60 Prevent Low Oxygen, Have Adequate Metabolite Flushing.............................................................7-60 4.1.4 Other Ecological Considerations.......................................................................................................7-61 SECTION 5: Implementation Plan ................................................................................................................. 7-62 5.1 Construct Flow Release Structure .............................................................................................................7-62 5.2 Construct Reach 4 Pump Station and Channel Modifications...................................................................7-62 5.3 Initiate Chelan River Comprehensive Management Plan Flow Releases..................................................7-63 5.4 M&E Program...........................................................................................................................................7-63 5.4.1 Benthic Community Analysis............................................................................................................7-63 5.4.2 Fish Community - Reaches 1-3 .........................................................................................................7-64 Fish Population - Fall-Spring ................................................................................................................7-64 Fish Population - Summer .....................................................................................................................7-64