Multi-Hazard Pre-Disaster Mitigation Plan For The City & County of Honolulu July 26, 2019 Prepared For Department of Emergency Management City & County of Honolulu 650 South King Street Honolulu, Hawaii 96813 TABLE OF CONTENTS Contents EXECUTIVE SUMMARY PLAN REVIEW TOOL FORM 1. INTRODUCTION .................................................................................................................... 1‐1 1.1 Overview ....................................................................................................................... 1‐1 1.2 The City and County of Honolulu .................................................................................. 1‐3 1.3 Hazards, Losses and Risk Management ........................................................................ 1‐5 1.4 State Hazard Mitigation Goals ...................................................................................... 1‐8 1.5 Organization of the Plan ............................................................................................... 1‐8 1.6 Accomplishments from the 2012 Priority Mitigation Projects ..................................... 1‐9 1.7 Digest of Significant Changes from 2012 to 2018 Multi‐Hazard Mitigation Plan ....... 1‐11 2. MITIGATION PLANNING PROCESS ........................................................................................ 2‐1 2.1 National Hazard Mitigation Planning Background Information ................................... 2‐2 2.1.1 The Stafford Act ..................................................................................................... 2‐2 2.1.2 The Disaster Mitigation Act of 2000 ...................................................................... 2‐2 2.1.3 44 CFR Part § 201.6 Local Mitigation Plans ........................................................... 2‐3 2.1.4 FEMA National Pre‐Disaster Mitigation Plan ......................................................... 2‐7 2.2 City and County of Honolulu Mitigation Planning ........................................................ 2‐8 2.2.1 Development of Pre‐Disaster Mitigation Plan ....................................................... 2‐8 2.2.2 Analysis. ............................................................................................................... 2‐11 2.2.3 Plan Development. .............................................................................................. 2‐11 2.2.4 Public Input. ......................................................................................................... 2‐14 2.2.5 City Multi‐Hazard Pre‐Disaster Mitigation Plan Update ‐ Advisory Committee Meeting ................................................................................................................ 2‐46 2.2.6 Adoption by the Local Jurisdiction ...................................................................... 2‐69 3. LAND USE AND DEVELOPMENT PLANNING.......................................................................... 3‐1 3.1 Population ..................................................................................................................... 3‐3 3.2 Land Use ........................................................................................................................ 3‐8 3.3 The General Plan ........................................................................................................... 3‐9 3.3.1 Content of the General Plan ................................................................................ 3‐11 3.3.2 Implementation of the General Plan ................................................................... 3‐11 3.4 Development Trends................................................................................................... 3‐12 3.5 Development Plans and Sustainable Communities Plans .......................................... 3‐13 3.5.1 Development Plan and Sustainable Communities Plan Revision Program ......... 3‐15 3.6 Zoning Ordinances and Functional Plans .................................................................... 3‐15 3.6.1 Functional Planning ............................................................................................. 3‐17 3.6.2 Review of Zoning and Other Development Applications .................................... 3‐17 3.6.3 Environmental Assessment ................................................................................. 3‐18 3.7 State Land Use Districts .............................................................................................. 3‐21 3.7.1 State Functional Plans ......................................................................................... 3‐22 3.7.2 State District Classification System ..................................................................... 3‐22 3.8 Lot Purchase ................................................................................................................ 3‐23 i 3.8.1 Mandatory Seller Disclosures in Real Estate Transactions .................................. 3‐25 3.8.2 Uniform Land Sales Practices Act ........................................................................ 3‐25 3.9 Plan Integration for Resilience ............................................................................. 3‐26 3.9.1 Introduction ......................................................................................................... 3‐26 3.9.2 Policy Analysis ...................................................................................................... 3‐28 3.10 Future Mitigation Projects .......................................................................................... 3‐41 4 CLIMATE CHANGE EFFECTS ...................................................................................................... 4‐1 4.1 Hazard Description ........................................................................................................ 4‐3 4.1.1 Understanding El Niño ........................................................................................... 4‐4 4.1.2 Climate Change Impacts on Society ...................................................................... 4‐6 4.2 Anticipated Future Coastal Hazard and Climate Impacts to the City and County of Honolulu .................................................................................................................................... 4‐7 4.3 Historical Relative Sea Level Rise .................................................................................. 4‐9 4.4 Anticipated Sea Level Rise for Hawaii ......................................................................... 4‐10 4.5 Estimating Changes in Tropical Cyclone Activity ........................................................ 4‐11 4.6 Vulnerability and Potential Losses from Climate Change ........................................... 4‐12 4.7 Costs from Climate‐Related Disasters ................................................................. 4‐12 4.8 Costs from Sea Level Rise .................................................................................... 4‐13 4.9 Adapting Building Construction and Civil Infrastructure to Climate Change ............. 4‐22 4.10 Adaptive Engineering .................................................................................................. 4‐23 4.11 Mitigation Strategies ................................................................................................... 4‐25 4.11.1 Carbon Footprint Reduction ................................................................................ 4‐25 4.11.2 Oʻahu Metropolitan Planning Organizaon: Transportaon Asset and Climate Change Risk Assessment Project ......................................................................... 4‐25 4.11.3 From the State Office of Planning 2017 report titled: Building Code Amendments to Reduce Existing and Future Building Stock Vulnerability to Coastal Hazards and Climate Impacts in the City and County of Honolulu .......................................... 4‐28 4.12 Future Mitigation Projects .......................................................................................... 4‐30 4.12.1 Ala Wai Canal Improvements .............................................................................. 4‐30 4.12.2 Coastal Roadway and Infrastructure Improvements .......................................... 4‐32 4.12.3 City Standards ...................................................................................................... 4‐32 5 COASTAL EROSION ................................................................................................................ 5‐1 5.1 Description of Hazard ................................................................................................... 5‐2 5.2 High Surf ........................................................................................................................ 5‐6 5.3 Impoundment ............................................................................................................... 5‐7 5.4 Sea Level ....................................................................................................................... 5‐9 5.5 Vulnerability Assessment ............................................................................................ 5‐11 5.6 Erosion Zone Calculations ........................................................................................... 5‐14 5.7 Hazard Intensity Rank ................................................................................................. 5‐16 5.7.1 Army Corps of Engineers ....................................................................................