Natural Hazards Mitigation Plan Prepared by: Cottage Grove Community Development Department Dianna C. Skelly-Cotter Amanda Ferguson & Natural Hazard Mitigation Advisory Committee Adopted by Cottage Grove City Council ________________ i | Page THIS PAGE IS INTENTIONALLY BLANK ii | Page Table of Contents Chapter 1: Natural Hazards Mitigation Plan ............................................ 2 Section 1: Introduction ............................................................................................................................. 2 What is Natural Hazard Mitigation? ..................................................................................................... 2 Why Develop a Mitigation Plan? .......................................................................................................... 3 Authorities: ........................................................................................................................................... 4 Policy Framework for Natural Hazard Mitigation in Oregon ................................................................ 5 Local Adoption ...................................................................................................................................... 6 Planning Process ................................................................................................................................... 6 Section 2: Community Profile ................................................................................................................... 8 Overview ............................................................................................................................................... 8 Future Expectations ............................................................................................................................ 15 Section 3: Mission, Goals, and Action Items ........................................................................................... 16 What are the Plan’s Missions and Goals ............................................................................................. 16 Mitigation Action Items ...................................................................................................................... 17 Section 4: Implementation, Maintenance and Public Participation ....................................................... 20 Plan Implementation .......................................................................................................................... 20 Implementation through Existing Programs ....................................................................................... 21 Multi-Jurisdictional Planning Efforts ................................................................................................... 21 Plan Maintenance ............................................................................................................................... 21 Project Prioritization Process .............................................................................................................. 22 Annual Meeting .................................................................................................................................. 25 Five Year Review of Plan ..................................................................................................................... 25 Continued Public Involvement and Participation ............................................................................... 26 Chapter 2: Hazard Assessment ............................................................. 28 Section 1: Hazard Assessment Overview ................................................................................................ 28 Definition of a Hazard Assessment ..................................................................................................... 28 Federal Requirements for a Hazard Assessment ................................................................................ 29 Hazard Quantification Categories ....................................................................................................... 30 Weight Factors, Scoring Guidelines .................................................................................................... 30 Hazard Assessment Mapping Methodology ....................................................................................... 32 Section 2: Local Hazard Assessment ....................................................................................................... 34 Relative Risk Assessment .................................................................................................................... 34 Vulnerability Assessment .................................................................................................................... 34 iii | Page Critical Facilities and Infrastructure .................................................................................................... 37 Section 3: Climate Change .................................................................................................................. 42 Chapter 3: Natural Hazards .................................................................... 44 Overview of Local Hazard Mitigation Mission and Goals ....................................................................... 44 Action Item Identification and Prioritization .......................................................................................... 46 Section 1: Flooding .................................................................................................................................. 48 Flooding Profile ................................................................................................................................... 48 Previous Occurrences ......................................................................................................................... 49 Flooding Hazard Assessment .............................................................................................................. 51 Repetitive Flood Loss .......................................................................................................................... 56 Existing Flood Mitigation Activities ..................................................................................................... 56 Flood Mitigation Projects .................................................................................................................... 57 Flood Mitigation Objectives and Action Items ................................................................................... 57 Section 2: Landslide ................................................................................................................................ 66 Landslide Profile .................................................................................................................................. 66 Landslide Hazard Assessment ............................................................................................................. 66 Existing Landslide Mitigation Activities .............................................................................................. 70 Landslide Mitigation Objectives and Action Items ............................................................................. 70 Section 3: Wildfire ................................................................................................................................... 74 Wildfire Profile .................................................................................................................................... 74 Wildfire Hazard Assessment ............................................................................................................... 74 Existing Wildfire Mitigation Activities ................................................................................................. 78 Wildfire Mitigation Objectives and Action Items................................................................................ 79 Section 4: Winter Storm .......................................................................................................................... 84 Winter Storm Profile ........................................................................................................................... 84 Winter Storm Hazard Assessment ...................................................................................................... 84 Existing Winter Storm Mitigation Activities ........................................................................................ 85 Winter and Severe Storm Mitigation Objectives and Action Items .................................................... 85 Section 5: Earthquake ............................................................................................................................. 88 Earthquake Profile .............................................................................................................................. 88 Earthquake Hazard Assessment ......................................................................................................... 90 Existing Earthquake Mitigation Activities ........................................................................................... 94 Earthquake Mitigation Action Items ................................................................................................... 94 Section 6: Drought .................................................................................................................................