United States Department of Agriculture Watershed Climate Change Vulnerability Assessment Lolo National Forest EXECUTIVE SUMMARY Forest Northern Region (R1) & Publication Number Publication Date Service Lolo National Forest R1-16-05 April 2016 Watershed Climate Change Vulnerability Assessment Lolo National Forest Executive Summary Authors Alisa Wade, Consultant Christine Brick, Clark Fork Coalition Scott Spaulding, USFS R1 Traci Sylte, USFS Lolo National Forest Joan Louie, USFS R1 Please cite this report as: Wade, A.A., C. Brick, S. Spaulding, T. Sylte, and J. Louie. April 2016. Watershed Climate Change Vulnerability Assessment: Lolo National Forest. Publication Number R1-16-05. Missoula, MT: U.S. Department of Agriculture, Forest Service, Northern Region and Lolo National Forest. 132 p. Full report available on-line at: http://www.fs.usda.gov/main/lolo/workingtogether. This report is a joint production of the USDA Forest Service Northern Region (R1) and Lolo National Forest. For further information, please contact: Traci Sylte Scott Spaulding Soil, Water, and Fisheries Program Manager Regional Fisheries Program Leader Lolo National Forest Northern Region (R1) 406.329.3896 406.329.3287 [email protected] [email protected] USDA is an equal opportunity provider, employer, and lender. Watershed Climate Change Vulnerability Assessment: Lolo National Forest Page i ACKNOWLEDGEMENTS This work arose in response to an inquiry from the Region 1 Office regarding Lolo National Forest’s interest in conducting a watershed vulnerability assessment. At a time of increasing demands and decreasing personnel and resources, this endeavor was made possible by partnering with the Clark Fork Coalition, which is given full credit for the Lolo National Forest’s ability to commit and produce this assessment. This report builds on the excellent previous vulnerability work conducted by: R1 (Gallatin and Helena); R2 (Grand Mesa, Uncompahgre, Gunnison, and White); R3 (Coconino); R4 (Sawtooth); R5 (Shasta-Trinity); R6 (Umatilla); R8 (Ouachita); R9 (Chequamegon-Nicolet), and R10 (Chugach) National Forests. These pilots were compiled with additional insights by Furniss and others (2013). We also thank D. Isaak, RMRS; S. Wenger, University of Georgia; and D. Nagel, RMRS for their generous help with data interpretation and development. A NOTE ABOUT TABLES AND FIGURES All tables and figures with alphanumeric designations (e.g., Table F.1) can be found within the body of this report. The letter represents the first letter of the report section name (e.g., F=Findings). All tables and figures designated with a only a number (e.g., Table 1, Figure 1) are not included in the body of this report, but are listed in Appendix 1 and 2, respectively. The tables and figures themselves can be found in the supplementary materials on the accompanying CD or on-line at http://www.fs.usda.gov/main/lolo/workingtogether. Watershed Climate Change Vulnerability Assessment: Lolo National Forest Page ii CONTENTS Acknowledgements ................................................................................................................................................................ ii A Note About Tables and Figures ...................................................................................................................................... ii Executive Summary .......................................................................................................................................................... ES-1 Introduction .................................................................................................................................................................... ES-1 Approach .......................................................................................................................................................................... ES-2 Methods Overview ....................................................................................................................................................... ES-3 Findings ............................................................................................................................................................................ ES-7 Management Implications ...................................................................................................................................... ES-27 Main Report ............................................................................................................................................................................... 1 1. Introduction .......................................................................................................................................................................... 2 1.1. Managing for Resilience in an Uncertain Future ........................................................................................... 3 2. Vulnerability: Conceptual Approach and Definitions .......................................................................................... 6 A Note About Uncertainty ............................................................................................................................................... 8 3. Methods ................................................................................................................................................................................ 10 3.1 Methods Overview and Climate Data Used in this Assessment ............................................................. 10 3.1.1 Study Area ............................................................................................................................................................ 10 3.1.2 Conceptual Models and General Methods .............................................................................................. 10 3.1.3 Climate Data ........................................................................................................................................................ 12 3.2. Methods for Calculating Exposure and Sensitivity Metrics and Indices ............................................ 14 3.2.1 Aquatic Resources: Bull Trout Methods .................................................................................................. 14 3.2.2 Water Supply Methods ................................................................................................................................... 26 3.2.3 Infrastructure Methods .................................................................................................................................. 28 4. Findings ................................................................................................................................................................................ 32 4.1 Aquatic Resources: Bull Trout Findings ........................................................................................................... 32 4.1.1 Bull Trout Findings: Exposure ..................................................................................................................... 32 4.1.2 Bull Trout Findings: Sensitivity .................................................................................................................. 35 4.1.3 Bull Trout Findings: Vulnerability ............................................................................................................. 42 4.2 Water Supply: Sufficient Water Supply Findings ......................................................................................... 44 4.2.1 Water Supply Findings: Exposure .............................................................................................................. 44 4.2.2 Water Supply Findings: Sensitivity ........................................................................................................... 46 4.2.3 Water Supply Findings: Vulnerability ...................................................................................................... 47 Watershed Climate Change Vulnerability Assessment: Lolo National Forest Page iii 4.3. Infrastructure: Recreation Sites, Trails, and Roads Findings ................................................................. 48 4.3.1 Infrastructure Findings: Exposure ............................................................................................................ 48 4.3.2 Infrastructure Findings: Sensitivity .......................................................................................................... 49 4.3.3 Infrastructure Findings: Vulnerability ..................................................................................................... 57 5. Management Implications ............................................................................................................................................. 60 A Reminder About Uncertainty ................................................................................................................................... 60 5.1 Bull trout: Management Implications ............................................................................................................... 62 5.2 Water Supply: Management Implications ....................................................................................................... 65 5.3 Infrastructure: Management Implications ...................................................................................................... 67 Appendix 1. List of Tables in Supplementary