2021 Santa Clarita Local Hazard Mitigation Plan

2021 Santa Clarita Local Hazard Mitigation Plan

2021 Santa Clarita Local Hazard Mitigation Plan 2021 Santa Clarita Local Hazard Mitigation Plan 10.02.2020 Interwest Consulting Group 1500 South Haven Avenue, Suite 220 Ontario, CA 91761 1 2021 Santa Clarita Local Hazard Mitigation Plan TABLE OF CONTENTS 1.0 INTRODUCTION………………………………………………………………………………………………………..…….……..… 15 1.1 PLAN PURPOSE ………………………..…………………………………………………………………………………….…..... 15-16 1.2 PLANNING APPROACH …………………………………………………………………………………………..…………..……... 16 1.3 HAZARD LAND USE POLICY IN CALIFORNIA …………………………………………………………………………..……. 17 1.4 STATE AND FEDERAL PARTNERS IN HAZARD MITIGATION PLANNING ……….…..……..……………... 17-18 1.5 STATE AND FEDERAL GUIDELINES AND REQUIREMENTS FOR HAZARD MITIGATION PLANS .……… 18 1.6 ORGANIZATION OF THIS PLAN …………………………………………………………………………………..………….. 18-19 2.0 PLANNING PROCESS………………………………..………………………………………………………..…………….…….. 20 2.1 STAKEHOLDER INVOLVEMENT ……………………………………………………………….……………….….………... 21-24 2.2 PUBLIC INVOLVEMENT…………………………………..…………………………………………………………….…………..... 24 2.2.1 Media Announcements ……………………………………………………………………………...……………… 25 2.2.2 Social Media………………………..………………………………..……………………………..………………..….. 26 2.2.3 CERT Program……………………….…………………………………..……………………………………………..... 26 2.2.4 2021 Hazard Mitigation Survey ………………………………………………………………….....….….. 26-31 2.3 CAPABILITIES ASSESSMENT – EXISTING PROCESSES AND PROGRAMS….……………………..……………... 31 2.3.1 Administrative and Technical Capacity.……………………..………………………...............……. 31-32 2.3.2 Fiscal Resources.……………………………………………………………………..……..………................ 32-33 2.3.3 Existing Plans, Policies, and Ordinances.………………………………………………….............……… 33 2.4 PUBLIC PARTICIPATION……………………..…………………………………………………………………………...…….……. 33 2.5 PLAN UPDATE METHOD AND SCHEDULE……………………………………………………………………...………….... 33 2.5.1 HMP Update Schedule……………………………………………………………………………….......….… 33-34 2.5.2 Continued Public Involvement………………………………………………………………............….…….. 34 3.0 COMMUNITY PROFILE…………………………………………………………..…………………..….....………….……….. 35 3.1 PLANNING AREA/BRIEF HISTORY OF SANTA CLARITA ……………………………………………....……………….. 35 3.1.1 Parks Located in Santa Clarita…………………….…………………………………….….............…….…… 35 3.1.2 Brief History of Santa Clarita……………….…………………………….….…………….............…….. 35-36 3.1.3 Historic Resources………………………………………………………….………………….............………. 36-39 3.2 POPULATION AND DEVELOPMENT TRENDS…………………………………………………………...…………….……. 40 3.2.1 Population and Demographics….……………………………….…………………………….............….….. 40 2 2021 Santa Clarita Local Hazard Mitigation Plan 3.2.2 Population Strengths and Vulnerabilities….……………………….………….….............……….. 41-42 3.2.3 Population Growth…………....……………………………….………………………….............………….…… 42 3.2.3.1 Annexations………………………………………………………………………………….……………….. 42 3.2.3.2 Major Development Projects under Construction in Santa Clarita…………………………….… 44 3.2.3.3 Major Development Projects Awaiting Construction……………………….……………… 44 3.2.3.4 Development Projects Under Review………………..……………………………….……….….. 45 3.2.4 Top Local Employers………………………………………………………………………………….............….… 45 3.3 CRITICAL FACILITIES…………………………………………………………………………………………………...……….……… 46 3.3.1 Capital Improvement Projects in Santa Clarita…………………………………………..............……. 46 3.3.2 Critical Facilities and Infrastructure………………………………………………………..............…….... 46 3.3.2.1 City Operated Critical Facilities…………………………………………………………...……. 46-47 3.3.2.2 Bridge Inventory – Santa Clarita Public Works Department as Responsible Agencies……………………………………………………………………………………………………. 47-48 3.3.2.3 Bridge Inventory – CalTrans District 7 as Responsible Agency……………………...… 48 3.3.2.4 Critical Facilities under County, State, or Regional Authority…………….………….... 49 4.0 HAZARD IDENTIFICATION AND RISK ASSESSMENT……………………….………..……........…….….. 51 4.1 WILDFIRE……….………………………………………………………………………………………………………....……………….. 54 4.1.1 Wildfire Factor: Fuel…………………………………………………………………………….….............….….. 54 4.1.2 Wildfire Factor: Topography………………………………………………….……………….............………. 55 4.1.3 Wildfire Factor: Weather……………………………………………………………………….............….……. 55 4.1.4 Wildfire Factor: Climate Change…………………………………………………………….............….……. 55 4.1.5 Wildfire Factor: Growth and Development in the Wildland Urban Interface...............… 56 4.1.5.1 Designated Hazard Areas……………………………………………………………………..…… 56-57 4.1.6 Southern California Wildfire History……………………………………..……………….............……….. 58 4.1.6.1 Top 20 Most Destructive California Wildfires…………………………….……..………….… 58 4.1.6.2 Santa Clarita Fires……………………………………..………………………………………………..…. 59 4.1.7 Wildfire Probability, Frequency, and Magnitude……………………………..…….............……..… 61 4.1.7.1 Wildfire Magnitude and Potential Damage ………….…………………………………...….. 61 4.2 EARTHQUAKE……………………………………………………………………………………………………...…………………..... 63 4.2.1 Earthquake Faults……………………………………………………………..………………..............……… 63-65 4.2.2 Earthquake Impacts and Failures………………………………………………………................……. 66-68 3 2021 Santa Clarita Local Hazard Mitigation Plan 4.2.3 Earthquake History…………………………………………………………………..……….............…........…. 68 4.2.3.1 Northridge Earthquake Impact on Santa Clarita……………………………….………….... 70 4.2.4 Earthquake Probability, Frequency, and Magnitude………………………..…….............…..…… 71 4.2.4.1 Earthquake Probability……………………………………………………………………….…..… 71-72 4.2.4.2 ShakeMap Scenario: Great Southern California ShakeOut…………………...…… 72-73 4.2.4.3 Magnitude and Scale……………………………………………………………………….…..…… 73-74 4.2.5 Exposure to Earthquakes – HAZUS Analysis: ……………………………….............……………….…. 75 4.2.5.1 Building Inventory ……………………………………………………………………………….…… 75-76 4.2.5.2 Building Related Losses ………………………………………………………………….………..……. 76 4.2.5.3 Building Damage ……………………………………………………………………………………….….. 76 4.2.5.4 Critical Facility Inventory …………………………………………………………………………..…… 76 4.2.5.5 Transportation and Utility Lifeline Inventory ………………………………………….... 76-77 4.2.5.6 Utility Lifeline Losses ………………………………………………………………………….………….. 77 4.2.5.7 Casualties ………………………………………………………………………………………….……… 77-78 4.2.5.8 Shelter Requirement ………………………………………………………………….………………….. 78 4.2.5.9 Total Economic Losses ……………………………………………………………………………….….. 78 4.3 ENERGY DISRUPTION ………………………………………………………………………………............…………...…….. 80 4.3.1 Energy Overview……………………………………………………………………………………..………….…..…. 80 4.3.1.1 Electricity…………………………………………………………………….………………………..……….. 80 4.3.1.2 Natural Gas……………….………………………………………………..……………………………..….. 80 4.3.2 Energy Disruption Hazard: Location and Extent……………………..………………………..….…..…. 80 4.3.2.1 Injuries………………………………………………………………………………………………..…………. 81 4.3.2.2 Personal Safety…………………………………………………………………………………………...…. 81 4.3.2.3 Power Outages…………………………………………..……………………………………………...….. 81 4.3.3 Energy Disruption Hazard: Community Assets………………………………….............……...…….. 81 4.3.3.1 Transportation Infrastructure………………………………………………..……………….…..…. 81 4.3.3.2 Pipelines……………………………………………………………………………………..…….….…… 81-82 4.3.3.3 Lifelines………………………………………………………………………………………………….………. 82 4.3.3.4 Services…………………………………………………………………………………………….………. 82-83 4.3.3.5 Economy………………………………………………………………………………………………………… 83 4.3.4 History of Power Outages………………………………………………………….................………..…. 83-84 4 2021 Santa Clarita Local Hazard Mitigation Plan 4.3.5 Energy Disruption Probability, Frequency, and Magnitude………….............……….……. 84-86 4.3.5.1 Deliberate Attacks…………………………………………………………………………………..…….. 86 4.3.5.2 Natural Disasters………………………………………………………………………………………...…. 86 4.3.5.3 Accidental Events………………………………………………………………………………….…… 86-87 4.3.5.4 Systemic Threats…………………………………………………………………………..………….….... 87 4.4 DROUGHT……………………………………………………………………………………………………………...……………..…… 88 4.4.1 Drought History ……………………………………………………………………….............……………..… 88-89 4.4.2 Drought Probability, Frequency, and Magnitude ………………………….............….……….. 89-90 4.4.2.1 Drought Magnitude and Scale ………………………………………………………….……..……. 91 4.4.2.2 Drought Probability and Frequency ……………………………………….…………………….… 91 4.4.3 Drought Vulnerabilities ……………………………………………………………………….............……….... 92 4.5 SEVERE WEATHER: EXTREME HEAT & EXTREME WIND……………………………………………...………………. 93 4.5.1 Extreme Heat Information and Background………………………………………..…….............……. 93 4.5.1.1 Extreme Heat Risk: Extent………………..……………………………………………………….. 94-95 4.5.2 Extreme Heat Losses and Impacts……………………………………………..………................………… 95 4.5.2.1 Health Impacts of Excessive Heat………………………………………………..……………. 95-96 4.5.2.2 Other Impacts of Excessive Heat……………………………………………………..…………..…. 96 4.5.3 Extreme Heat History……………………………………………………………………..………................…… 96 4.5.4 Extreme Heat Probability, Frequency, and Magnitude……………....……….......................... 97 4.5.5 Extreme Wind Background and Information………………………………..…........................ 98-99 4.5.6 Extreme Wind History…………………………………………………………………...........…….………..…. 100 4.5.7 Extreme Wind Effects: Extent………………………………………………………….............………...…. 101 4.5.7.1 Life and Property……………………………………………………………….………………..... 101-102 4.5.7.2 Utilities/Infrastructure……………………………………………………………..………………….. 102 4.5.7.3 Increased Wildfire Threat…………………………………………………………………………..… 102 4.5.7.4 Transportation…………………………………………………………………………………………….. 102 4.5.8 Extreme Wind Probability, Frequency and Magnitude………………………...........…………… 103 4.5.8.1 Wind Damage Scale: Magnitude……………………………..……………………..………….… 103 4.6 PANDEMICS……………………………………………………………………………………………………...………………….….. 105 4.6.1 Pandemic History………………………………………………………….............………………..………

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