FINAL Orange County Regional Water and Wastewater Hazard Mitigation Plan Prepared by: MUNICIPAL WATER DISTRICT OF ORANGE COUNTY 18700 Ward Street Fountain Valley, California 92708 Contact: Kelly Hubbard WEROC Programs Manager 714.593.5010 MICHAEL BAKER INTERNATIONAL 5 Hutton Centre Drive, Suite 500 Santa Ana, California 92707 Contact: Ms. Kristen Bogue 949.855.5747 GPA CONSULTING 2642 Michelle Drive, Suite 110 Tustin, California 92780 Contact: Ms. Starla Barker, AICP 310.792.2690 August 2019 JN 161720 This document is designed for double-sided printing to conserve natural resources. TABLE OF CONTENTS Section 1.0 Introduction................................................................................................................................... 1-1 1.1 Purpose of the Plan and Authority ....................................................................................... 1-3 1.2 Multi-Jurisdictional Participation........................................................................................... 1-5 1.2.1 Overview of Water and Wastewater Systems in Orange County .............................. 1-5 1.2.2 Participating Jurisdictions .......................................................................................... 1-6 1.3 What is New/What Has Changed from the 2012 Plan ......................................................... 1-8 1.4 Plan Organization ................................................................................................................ 1-9 Section 2.0 Planning Process Documentation .............................................................................................. 2-1 2.1 Organizing Resources ......................................................................................................... 2-1 2.1.1 Project Management Team ....................................................................................... 2-2 2.1.2 Planning Team .......................................................................................................... 2-2 2.1.3 Public Outreach ........................................................................................................ 2-6 2.1.4 Review and Incorporate Existing Information ............................................................ 2-8 2.2 Assess Risks ....................................................................................................................... 2-8 2.2.1 Identify/Profile Hazards ............................................................................................. 2-9 2.2.2 Assess Vulnerabilities ............................................................................................... 2-9 2.3 Develop Mitigation Plans ..................................................................................................... 2-9 2.3.1 Identify Goals ............................................................................................................ 2-9 2.3.2 Develop Capabilities Assessment ............................................................................. 2-9 2.3.3 Identify Mitigation Actions ....................................................................................... 2-10 2.3.4 Plan Review and Revision ...................................................................................... 2-10 2.3.5 Plan Adoption and Submittal ................................................................................... 2-10 2.3.6 Plan Maintenance ................................................................................................... 2-10 Section 3.0 Risk Assessment .......................................................................................................................... 3-1 3.1 Hazard Identification and Prioritization ................................................................................ 3-1 3.1.1 Hazard Identification ................................................................................................. 3-1 3.1.2 Hazard Prioritization .................................................................................................. 3-4 3.2 Hazard Profiles .................................................................................................................... 3-6 3.2.1 Climate Change ........................................................................................................ 3-7 3.2.2 Coastal Storms/Erosion ............................................................................................ 3-9 3.2.3 Contamination/Salt Water Intrusion ........................................................................ 3-11 3.2.4 Dam/Reservoir Failure ............................................................................................ 3-13 3.2.5 Drought ................................................................................................................... 3-21 3.2.6 Earthquake Fault Rupture & Seismic Hazards (Ground Shaking & Liquefaction) ... 3-26 3.2.7 Flood ....................................................................................................................... 3-40 3.2.8 Geologic Hazards (Expansive Soils & Land Subsidence) ....................................... 3-45 3.2.9 High Winds/Santa Ana Winds ................................................................................. 3-49 3.2.10 Landslide/Mudflow .................................................................................................. 3-52 3.2.11 Tsunami .................................................................................................................. 3-57 3.2.12 Wildland/Urban Fire ................................................................................................ 3-61 3.2.13 Human-Caused Hazards ......................................................................................... 3-66 3.2.14 Power Outage ......................................................................................................... 3-71 3.3 Vulnerability Assessment ................................................................................................... 3-72 3.3.1 Asset Inventory ....................................................................................................... 3-73 Final | August 2019 i TABLE OF CONTENTS 3.3.2 Estimating Potential Exposure and Losses ............................................................. 3-73 3.3.3 Land Use Development and Trends/Changes in Development .............................. 3-74 3.3.4 Vulnerable Populations ........................................................................................... 3-75 3.4 Summary of Vulnerability ................................................................................................... 3-76 Section 4.0 Mitigation Strategy ....................................................................................................................... 4-1 4.1 Hazard Mitigation Overview ................................................................................................. 4-1 4.1.1 FEMA’s National Flood Insurance Program .............................................................. 4-1 4.2 Hazard Mitigation Goals ...................................................................................................... 4-2 4.3 Identify and Prioritize Mitigation Actions .............................................................................. 4-2 4.3.1 Hazard Mitigation Benefit-Cost Review ..................................................................... 4-3 4.4 Regional Considerations ...................................................................................................... 4-6 4.4.1 Regional Fiscal Resources ....................................................................................... 4-7 Section 5.0 Plan Maintenance ......................................................................................................................... 5-1 5.1 Monitoring, Evaluating and Updating the Plan ..................................................................... 5-1 5.1.1 Plan Maintenance ..................................................................................................... 5-1 5.1.2 Plan Evaluation ......................................................................................................... 5-1 5.1.3 Plan Updates ............................................................................................................ 5-2 5.1.4 Adoption .................................................................................................................... 5-3 5.1.5 Implementation Through Existing Programs ............................................................. 5-3 5.1.6 Continued Public Involvement ................................................................................... 5-6 Section 6.0 References .................................................................................................................................... 6-1 APPENDICES Appendix A Agency Adoption Resolutions Appendix B Planning Process Documentation Final | August 2019 ii TABLE OF CONTENTS LIST OF FIGURES Figure 1-1 Member Agency Participants ........................................................................................................ 1-10 Figure 3-1 March 17, 2018 PDSI ................................................................................................................... 3-24 Figure 3-2 July 26, 2014 PDSI ......................................................................................................................