i Draft Lower Mid-Columbia Mainstem Subbasin Plan Includes Rock Creek, Washington 12/08/2004 Prepared for the Northwest Power and Conservation Council i Lower Mid-Columbia Mainstem Subbasin Plan Table of Contents 1 Contributors .............................................................................................................................1 1.1 Lead Organizations...............................................................................................................1 1.2 Coordinators .........................................................................................................................1 1.3 Participants and Contributors...............................................................................................1 1.3.1 Rock Creek Working Group Participants .......................................................................1 1.3.2 Rock Creek Information Meeting Participants ...............................................................1 1.3.3 Wildlife Participants and Reviewers...............................................................................1 1.3.4 Oregon Contributors.......................................................................................................1 1.3.5 Mainstem Contributors...................................................................................................2 1.3.6 Technical Writers............................................................................................................2 1.3.7 Reviewer .........................................................................................................................2 1.4 Subbasin Plan Approach and Public Involvement ...............................................................2 1.4.1 Description Planning Unit...............................................................................................3 1.4.2 Vision Statement .............................................................................................................4 2 Executive Summary.................................................................................................................5 2.1 Purpose and Scope................................................................................................................5 2.2 Public Involvement...............................................................................................................7 2.3 Vision Statement ..................................................................................................................8 2.4 Subbasin Goals.....................................................................................................................8 2.5 Focal Species and Habitats in the Current Planning Area....................................................8 2.6 Key Findings and Limiting Factors......................................................................................9 2.6.1 Washington Area of the Subbasin...................................................................................9 2.6.2 Oregon Area of the Subbasin........................................................................................12 2.6.3 Mainstem Area of the Subbasin ....................................................................................13 2.7 Management Objectives and Strategies..............................................................................15 2.7.1 Wildlife .........................................................................................................................16 2.7.2 Fish................................................................................................................................16 2.8 Adaptive Management of the Subbasin..............................................................................17 3 Subbasin Overview ................................................................................................................19 3.1.1 Subbasin in Regional Context.......................................................................................19 3.1.2 Aquatic/Terrestrial Relationships..................................................................................21 3.2 Subbasin Description..........................................................................................................22 3.2.1 General Location...........................................................................................................22 3.2.2 Topographic/Physio-geographic Environment .............................................................22 3.2.3 Climate and Weather.....................................................................................................23 3.2.4 Land Cover and Vegetation ..........................................................................................23 3.2.5 Hydrology and Hydrography ........................................................................................24 3.2.6 Jurisdictions and Land Ownership................................................................................30 3.2.7 Land Use and Demographics ........................................................................................31 3.2.8 Anthroprogenic Disturbances on Aquatic and Terrestrial Environments.....................35 3.2.9 Terrestrial/Wildlife Resources......................................................................................42 3.2.10 Aquatic/Fish Resources.................................................................................................47 4 Wildlife Assessment ...............................................................................................................55 ii 4.1.1 Introduction...................................................................................................................55 4.1.2 Wildlife Assessment Methodology...............................................................................55 4.1.3 Wildlife Habitats and Features in the Lower Mid-Columbia Mainstem Subbasin.......58 4.1.4 Focal Terrestrial/Wildlife Habitat Selection and Rationale..........................................63 4.1.5 Focal Terrestrial/Wildlife Habitats for the Lower Mid-Columbia Mainstem Subbasin ........................................................................................................................65 4.1.6 Focal Wildlife Species Selection and Rationale ...........................................................67 4.1.7 Focal Wildlife in the Lower Mid-Columbia Mainstem Subbasin.................................68 4.2 Discussion of Focal Habitats and their Representative Focal Species...............................72 4.3 Interior Riparian Wetlands .................................................................................................72 4.3.1 Yellow Warbler (Dendroica petechia) .........................................................................79 4.3.2 American Beaver (Castor canadensis) .........................................................................83 4.3.3 Lewis’ Woodpecker (Melanerpes lewis) ......................................................................88 4.3.4 Interior Riparian Wetlands Key Findings, Limiting Factors, and Working Hypotheses ....................................................................................................................93 4.4 Shrub Steppe/Interior Grasslands.......................................................................................95 4.4.1 Rocky Mountain Mule Deer (Odocoileus hemionus hemionus)/Columbian black- tailed deer (Odocoileus hemionus columbianus) ........................................................100 4.4.2 Grasshopper Sparrow (Ammodramus savannarum) ...................................................113 4.4.3 Brewer’s Sparrow (Spizella breweri)..........................................................................119 4.4.4 Shrub Steppe/Interior Grasslands and Focal Species Key Findings, Limiting Factors and Working Hypotheses ...............................................................................124 4.5 Ponderosa Pine (Pinus ponderosa)/Oregon White Oak (Quercus garryanna) ................127 4.5.1 Western Gray Squirrel (Sciurus griseus) ....................................................................135 4.5.2 White-Headed Woodpecker (Picoides albolarvatus) .................................................139 4.5.3 Ponderosa Pine/Oregon White Oak Habitat and Focal Species Key Findings, Limiting Factors and Working Hypotheses ................................................................144 4.6 Habitat of Concern: Lower Mid-Columbia Mainstem .....................................................146 4.7 Habitat of Concern: Agriculture.......................................................................................148 5 Fish Assessment....................................................................................................................150 5.1 Introduction ......................................................................................................................150 5.1.1 Fish Focal Species and Species of Interest .................................................................150 5.1.2 Rationale for Selection of Focal Fish Species ............................................................150 5.2 White Sturgeon.................................................................................................................153 5.3 Steelhead...........................................................................................................................166