CITY OF RANCHO SANTA MARGARITA LOCAL HAZARD MITIGATION PLAN Lead Agency: CITY OF RANCHO SANTA MARGARITA 22112 El Paseo Rancho Santa Margarita, CA 92688 Contact: Ms. Wendy Starks, AICP, Principal Planner Planning Department (949) 635-1807 Prepared by: MICHAEL BAKER INTERNATIONAL 5 Hutton Centre Drive, Suite 500 Santa Ana, California 92707 Contact: Mr. Eddie Torres (949) 855-3612 GPA CONSULTING Contact: Ms. Starla Barker, AICP (310) 792-2690 December 2019 JN 169696 Rancho Santa Margarita Local Hazard Mitigation Plan TABLE OF CONTENTS Section 1.0 Introduction ...................................................................................................... 1-1 1.1 Plan Purpose ............................................................................................................... 1-1 1.2 Plan Authority .............................................................................................................. 1-2 1.3 Plan Adoption ............................................................................................................. 1-3 1.4 Plan Organization ...................................................................................................... 1-3 1.5 Mitigation Goals ......................................................................................................... 1-4 Section 2.0 Planning Process ............................................................................................. 2-1 2.1 Organizing Resources ................................................................................................ 2-1 2.1.1 Project Management Team ........................................................................ 2-2 2.1.2 LHMP Planning Team ..................................................................................... 2-2 2.1.3 Public Outreach ............................................................................................. 2-5 2.1.4 Review and Incorporate Existing Information ........................................... 2-7 2.2 Assess Risks ................................................................................................................... 2-7 2.2.1 Identify/Profile Hazards ................................................................................. 2-8 2.2.2 Assess Vulnerabilities ...................................................................................... 2-8 2.3 Develop Mitigation Plan ........................................................................................... 2-8 2.3.1 Identify Goals .................................................................................................. 2-8 2.3.2 Develop Capabilities Assessment ............................................................... 2-8 2.3.3 Identify Mitigation Actions ............................................................................ 2-8 2.3.4 Plan Review and Revision ............................................................................. 2-9 2.3.5 Plan Adoption and Submittal ...................................................................... 2-9 2.3.6 Plan Maintenance ......................................................................................... 2-9 Section 3.0 Community Profile ........................................................................................... 3-1 3.1 Physical Setting ........................................................................................................... 3-1 3.2 History ........................................................................................................................... 3-1 3.3 Demographics ............................................................................................................ 3-2 3.3.1 Population ....................................................................................................... 3-2 3.3.2 Educational Attainment ............................................................................... 3-7 3.3.3 Employment .................................................................................................... 3-8 3.3.4 Housing ............................................................................................................ 3-8 3.4 Land Uses and Existing Development .................................................................... 3-8 3.5 Development Trends and Future Development ................................................. 3-14 3.6 Infrastructure Systems .............................................................................................. 3-15 3.6.1 Transportation ............................................................................................... 3-15 3.6.2 Water and Wastewater .............................................................................. 3-16 3.6.3 Electricity ....................................................................................................... 3-16 December 2019 i Table of Contents Rancho Santa Margarita Local Hazard Mitigation Plan 3.6.4 Natural Gas ................................................................................................... 3-17 3.7 Critical Facilities and Facilities of Concern .......................................................... 3-17 Section 4.0 Hazard Assessment ......................................................................................... 4-1 4.1 Hazard Identification and Prioritization .................................................................. 4-1 4.2 Hazard Profiles ............................................................................................................ 4-6 4.2.1 Dam/Reservoir Failure .................................................................................. 4-6 4.2.2 Drought ........................................................................................................... 4-9 4.2.3 Flood ............................................................................................................. 4-14 4.2.4 Human-Induced Hazards .......................................................................... 4-22 4.2.5 Landslide/Mudflow ..................................................................................... 4-31 4.2.6 Pest Management and Disease .............................................................. 4-36 4.2.7 Seismic Hazards ........................................................................................... 4-41 4.2.8 Severe Weather .......................................................................................... 4-51 4.2.9 Wildfire .......................................................................................................... 4-58 4.3 Vulnerability/Risk Assessment ................................................................................. 4-66 Section 5.0 Mitigation Strategy .......................................................................................... 5-1 5.1 Hazard Mitigation Overview .................................................................................... 5-1 5.2 Hazard Mitigation Actions ........................................................................................ 5-4 5.3 Capabilities Assessment ............................................................................................ 5-9 Section 6.0 Plan Maintenance ........................................................................................... 6-1 6.1 Purpose of the Plan and Authority .......................................................................... 6-1 6.2 Method and Schedule for Updating the Plan within Five Years ........................ 6-3 6.3 Adoption ...................................................................................................................... 6-4 6.4 Implementation Through Existing Programs .......................................................... 6-5 6.5 Incorporation into Existing Planning Mechanisms ................................................ 6-5 6.6 Continued Public Involvement ................................................................................ 6-6 6.7 Point of Contact ......................................................................................................... 6-6 Section 7.0 References ....................................................................................................... 7-1 LIST OF APPENDICES Appendix A City Adoption Resolution Appendix B Planning Process Documentation Table of Contents ii December 2019 Rancho Santa Margarita Local Hazard Mitigation Plan LIST OF FIGURES Figure 1-1 Disaster Response Cycle ..................................................................................... 1-1 Figure 3-1 Regional Location ................................................................................................ 3-3 Figure 3-2 City and Sphere of Influence ............................................................................. 3-5 Figure 3-3 General Plan Land Use Map .............................................................................. 3-9 Figure 3-4 Rancho Santa Margarita Planned Communities ......................................... 3-11 Figure 3-5 Rancho Santa Margarita Critical Facilities and Facilities of Concern ...... 3-23 Figure 4-1 Drought Monitor Map ....................................................................................... 4-11 Figure 4-2 U.S. Seasonal Drought Outlook ........................................................................ 4-13 Figure 4-3 Flood Hazard Zone ............................................................................................