Yakima River Basin Storage Alternatives Appraisal Assessment A component of Yakima River Basin Water Storage Feasibility Study, Washington Technical Series No. TS-YSS-8 Bumping Lake Wymer Damsite Keechelus-to-Kachess Pipeline U.S. Department of the Interior Bureau of Reclamation Pacific Northwest Region May 2006 The mission of the U.S. Department of the Interior is to protect and provide access to our Nation’s natural and cultural heritage and honor our trust responsibilities to Indian Tribes and our commitments to island communities. 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. Yakima River Basin Storage Alternatives Appraisal Assessment A component of Yakima River Basin Water Storage Feasibility Study, Washington Technical Series No. TS-YSS-8 U.S. Department of the Interior Bureau of Reclamation Pacific Northwest Region May 2006 Frontispiece CONTENTS Executive Summary...............................................................................................1 Chapter 1.0 Introduction....................................................................................1 1.1 Storage Study...................................................................................1 1.2 Authorization ...................................................................................1 1.3 Purpose and Need ............................................................................1 1.4 Storage Study Goals.........................................................................2 1.5 State of Washington Participation ...................................................2 1.6 Process .............................................................................................3 1.7 Black Rock Alternative....................................................................3 Chapter 2.0 Yakima River Basin Storage Alternatives Appraisal Assessment......................................................................................5 2.1 Purpose.............................................................................................5 2.2 Scope................................................................................................5 Chapter 3.0 Prior Yakima River Basin Storage Studies .................................7 3.1 Bumping Lake Enlargement Joint Feasibility Report......................7 3.1.1 Purpose.................................................................................7 3.1.2 Scope of Study.....................................................................8 3.1.3 Water Supply Goals.............................................................8 3.1.4 Water Operation Studies......................................................8 3.1.5 Storage Alternatives Considered .......................................11 3.1.6 Other Considerations.........................................................11 3.1.7 Primary Conclusions/Recommendations...........................11 3.1.8 Actions Taken....................................................................12 3.2 Yakima River Basin Water Enhancement Project Feasibility Study ............................................................................12 3.2.1 Background........................................................................12 3.2.2 Yakima River Basin Water Enhancement Project Plan Formulation Summary Report.......................14 3.2.2.1 Water Supply Goals...............................................14 3.2.2.2 Alternative Plans....................................................15 3.2.2.3 Water Operation Studies........................................15 3.2.2.4 Primary Conclusions..............................................20 3.3 A 20/20 Vision for a Viable Future of the Water Resource of the Yakima River Basin.............................................20 3.3.1 Introduction........................................................................20 i Contents 3.3.2 Scope..................................................................................21 3.3.3 Water Supply Goals...........................................................21 3.3.3.1 Irrigation Surface Water Supply Goal ...................22 3.3.3.2 Instream Flow Water Supply Goal ........................22 3.3.3.3 Municipal Water Supply Goal ...............................22 3.3.4 Storage Alternatives Considered .......................................23 3.3.5 Primary Conclusions..........................................................24 3.4 Watershed Management Plan, Yakima River Basin ......................25 3.4.1 Purpose...............................................................................25 3.4.2 Scope of Plan .....................................................................25 3.4.3 Water Supply Goals...........................................................26 3.4.3.1 Irrigated Agriculture ..............................................26 3.4.3.2 Instream Flow ........................................................26 3.4.3.3 Municipal and Domestic Supply............................27 3.4.4 Storage Alternatives Considered .......................................30 3.4.5 Water Operation Studies....................................................30 3.4.6 Model Results....................................................................31 3.4.7 Primary Conclusions..........................................................34 3.5 Resource Issues Raised..................................................................34 3.5.1 Bumping Lake Enlargement ..............................................35 3.5.1.1 Proximity to William O. Douglas Wilderness Area.................................................................35 3.5.1.2 Inundation of Old Growth Timber.........................35 3.5.1.3 Loss of Stream and Wildlife Habitat .....................35 3.5.1.4 Reservoir Filling and Refilling ..............................36 3.5.1.5 Relocation of Summer Homes and Recreational Facilities........................................................36 3.5.1.6 Impacts to the Community of Goose Prairie.................................................................................36 3.5.2 Wymer Dam and Reservoir ...............................................36 Chapter 4.0 Storage Study Goals.....................................................................39 4.1 Fish Habitat....................................................................................39 4.1.1 Existing Conditions............................................................39 4.1.2 Desired Conditions ............................................................41 4.2 Dry-Year Irrigation........................................................................43 4.3 Municipal .......................................................................................45 Chapter 5.0 Water Rights.................................................................................47 5.1 Yakima Reclamation Project Water Rights ...................................47 ii Contents 5.2 May 10, 1905, Withdrawal ............................................................47 5.3 February 17, 1981, Withdrawal .....................................................49 5.4 Relationship to Yakima Basin Storage Projects ............................50 Chapter 6.0 Yakima River Basin Storage Alternatives Characteristics..............................................................................51 6.1 Bumping Lake Enlargement ..........................................................51 6.1.1 Site Characteristics............................................................51 6.1.1.1 Location .................................................................51 6.1.1.2 Topography............................................................51 6.1.1.3 Geology..................................................................51 6.1.1.3.2 Spillway and Outlet Works Geology..................................................................55 6.1.1.3.3 Reservoir Geology .................................55 6.1.1.4 Groundwater ..........................................................57 6.1.1.5 Seismotectonics .....................................................57 6.1.1.6 Probable Maximum Flood .....................................58 6.1.2 Project Facilities................................................................58 6.1.2.1 Dam Alignment......................................................59 6.1.2.2 Dam Foundation ....................................................60 6.1.2.3 Dam Structure........................................................60 6.1.2.4 Reservoir................................................................63 6.1.2.5 Spillway .................................................................63 6.1.2.6 Outlet Works..........................................................63 6.1.2.7 Existing Bumping Lake Dam ................................64 6.2 Wymer Dam and Reservoir ...........................................................64 6.2.1 Site Characteristics............................................................64 6.2.1.1 Location .................................................................64 6.2.1.2 Topography............................................................66 6.2.1.3 Geology..................................................................66 6.2.1.4 Groundwater ..........................................................69 6.2.1.5 Seismicity...............................................................69