Hazard Mitigation Plan City of New Orleans Office of Homeland Security and Emergency Preparedness January 7, 2021 1300 Perdido Street, Suite 9W03 (504) 658-8740 ready.nola.gov/hazard-mitigation DRAFT – January 7, 2020 1 Table of Contents Section 1: Introduction ................................................................................................................... 9 1.1 New Orleans Community Profile ...................................................................................................... 11 1.1.1 Location ..................................................................................................................................... 11 1.1.2 History of Orleans Parish ........................................................................................................... 12 1.1.3 Climate ....................................................................................................................................... 14 1.1.4 Transportation ............................................................................................................................ 15 1.1.5 Community Assets ..................................................................................................................... 17 1.1.6 Land Use and Zoning ................................................................................................................. 18 1.1.7 Population .................................................................................................................................. 24 1.1.8 Economy .................................................................................................................................... 28 1.2 Hazard Mitigation Planning Overview ............................................................................................. 29 1.2.1 General Strategy ......................................................................................................................... 31 1.2.2 2020 Plan Update ....................................................................................................................... 31 Section 2: Hazard Identification and Parish-Wide Risk Assessment .................................... 35 2.1 Hazard Summary ............................................................................................................................. 35 2.1.1 Previous Occurrences of Major Disasters .................................................................................. 36 2.1.2 Probability of Future Hazard Events .......................................................................................... 40 2.2 Hazard Identification ........................................................................................................................ 41 2.2.1 Flooding ..................................................................................................................................... 41 2.2.2 Flash Flooding and Urban Flooding .......................................................................................... 53 2.2.3 Riverine Flooding ...................................................................................................................... 60 2.2.4 Storm Surge and Coastal Flooding ............................................................................................ 61 2.3 Tropical Cyclones ......................................................................................................................... 76 2.4 Coastal Erosion ............................................................................................................................. 84 2.5 Tornadoes ...................................................................................................................................... 94 2.6 Subsidence .................................................................................................................................... 99 2.7 Winter Weather ........................................................................................................................... 108 2.8 Extreme Heat .............................................................................................................................. 117 2.9 Severe Thunderstorm - High Winds ........................................................................................... 122 2.10 Severe Thunderstorms - Lightning ........................................................................................... 126 2.11 Hazard Identification – Man-Made Hazards ................................................................................. 128 2.12 Hazardous Materials Spills/Contamination .............................................................................. 128 2.13 Active Threats - Terrorism ........................................................................................................ 136 DRAFT – January 7, 2020 2 2.14 Infrastructure Failure - Levee Failure ....................................................................................... 139 2.15 Infrastructure Failure - Building Collapse ................................................................................ 145 2.16 Infrastructure Failure - Water Systems ..................................................................................... 147 2.17 Infrastructure Failure - Power Outage ...................................................................................... 149 2.18 Infectious Disease Outbreak ..................................................................................................... 154 2.19 Economic Shock ........................................................................................................................... 159 Section 3: The Capability Assessment ...................................................................................... 161 3.1 Policies, Plans, and Programs ......................................................................................................... 161 3.1.1 Master Plan .............................................................................................................................. 161 3.1.2 The Comprehensive Zoning Ordinance (CZO) ........................................................................ 162 3.1.3 City Assisted Evacuation Plan (CAEP) ................................................................................... 162 3.1.4 Other Plans ............................................................................................................................... 162 3.2 Building Codes, Permitting, Land Use Planning and Ordinances .................................................. 165 3.3 Administration and Technical Capabilities ..................................................................................... 165 3.3.1 Automated Flood Warning System (AFWS) ........................................................................... 166 3.3.2 Voluntary Organizations Active in Disaster (VOAD) ............................................................. 167 3.3.3 Some highlights from 2019 and 2020: .................................................................................... 168 3.4 Financial Capabilities ...................................................................................................................... 170 3.5 Education and Outreach .................................................................................................................. 170 3.5.1 Sheltering ................................................................................................................................. 171 3.5.2 Evacuation ................................................................................................................................ 171 3.6 Flood Insurance and Community Rating System ............................................................................ 172 3.6.1 National Flood Insurance Program .......................................................................................... 172 3.7 Repetitive Loss Properties .............................................................................................................. 173 3.7.1 Inventory of Assets for the Entire Parish ................................................................................. 178 3.8 New Orleans Floodplain Management Regulations and Enforcement ........................................... 182 3.8.1 Introduction .............................................................................................................................. 182 3.8.2 Building Codes, Permitting, and Inspections ........................................................................... 182 3.8.3 Building Code Effectiveness Grading Schedule ...................................................................... 183 3.9 Land Use Planning and Ordinances ................................................................................................ 183 3.9.1 The Comprehensive Zoning Ordinance (CZO) ........................................................................ 183 3.9.2 Subdivision Ordinance ............................................................................................................. 184 3.9.3 Floodplain Ordinance ............................................................................................................... 184 3.9.4 Stormwater Ordinance [Stormwater Code] .............................................................................. 185 DRAFT – January 7,