VALLEY COUNCIL OF GOVERNMENTS MULTI-JURISDICTION HAZARD MITIGATION PLAN For Ansonia, Derby, Seymour, and Shelton AUGUST 2012 FEMA Approval Pending Adoption (APA) Issued October 11, 2012 Adopted November 20, 2012 MMI #3211-04-4 Prepared for: VALLEY COUNCIL OF GOVERNMENTS 12 Main Street Derby, Connecticut 06418-1931 (203) 735-8688 http://www.valleycog.org/ The preparation of this report has been financed in part through funds provided by the Connecticut Department of Energy & Environmental Protection under a grant from the Federal Emergency Management Agency. The contents of this report reflect the views of the Valley Council of Governments and its member towns and do not necessarily reflect the official views of the Connecticut Department of Energy & Environmental Protection. The report does not constitute a specification or regulation. Prepared by: MILONE & MACBROOM, INC. 99 Realty Drive Cheshire, Connecticut 06410 (203) 271-1773 www.miloneandmacbroom.com TABLE OF CONTENTS Section Page CONTACT INFORMATION ....................................................................................................ES-1 EXECUTIVE SUMMARY .......................................................................................................ES-2 1.0 INTRODUCTION 1.1 Background and Purpose ................................................................................................. 1-1 1.2 Hazard Mitigation Goals .................................................................................................. 1-4 1.3 Identification of Hazards and Document Overview ........................................................ 1-5 1.4 Discussion of STAPLEE Ranking Method...................................................................... 1-9 1.5 Discussion of Benefit-Cost Ratio................................................................................... 1-11 1.6 Documentation of the Planning Process ........................................................................ 1-12 1.7 Coordination with Neighboring Communities ............................................................... 1-15 2.0 COMMUNITY PROFILES 2.1 Physical Setting ................................................................................................................ 2-1 2.2 Existing Land Use ............................................................................................................ 2-3 2.3 Geology ............................................................................................................................ 2-4 2.4 Climate ........................................................................................................................... 2-12 2.5 Drainage Basins and Hydrology .................................................................................... 2-12 2.6 Population and Demographic Setting ............................................................................ 2-15 2.7 Development Trends ...................................................................................................... 2-16 2.8 Governmental Structure ................................................................................................. 2-21 2.9 Review of Existing Plans ............................................................................................... 2-24 2.10 Review of Existing Regulations..................................................................................... 2-28 2.11 Critical Facilities, Sheltering Capacity, and Evacuation ............................................... 2-35 3.0 FLOODING 3.1 Setting .............................................................................................................................. 3-1 3.2 Hazard Assessment .......................................................................................................... 3-1 3.3 Historic Record ................................................................................................................ 3-6 3.4 Existing Programs, Policies, Capabilities, and Mitigation .............................................. 3-9 3.5 Vulnerabilities and Risk Assessment ............................................................................. 3-14 3.5.1 Vulnerability Analysis of Specific Areas ............................................................ 3-14 3.5.2 Vulnerability Analysis of Private Properties ....................................................... 3-39 3.5.3 Vulnerability Analysis of Critical Facilities ........................................................ 3-43 3.5.4 HAZUS-MH Vulnerability Analysis .................................................................... 3-44 3.6 Potential Mitigation Measures, Strategies, and Alternatives ......................................... 3-46 3.6.1 Prevention ............................................................................................................ 3-46 MULTI-JURISDICTION HAZARD MITIGATION PLAN VALLEY COUNCIL OF GOVERNMENTS AUGUST 2012 TC-i TABLE OF CONTENTS (Continued) 3.6.2 Property Protection .............................................................................................. 3-49 3.6.3 Emergency Services ............................................................................................. 3-50 3.6.4 Public Education and Awareness ......................................................................... 3-51 3.6.5 Natural Resource Protection ................................................................................ 3-51 3.6.6 Structural Projects ................................................................................................ 3-52 3.7 Summary of Recommended Mitigation Measures, Strategies, and Alternatives .......... 3-52 4.0 HURRICANES AND TROPICAL STORMS 4.1 Setting .............................................................................................................................. 4-1 4.2 Hazard Assessment .......................................................................................................... 4-1 4.3 Historic Record ................................................................................................................ 4-3 4.4 Existing Programs, Policies, Capabilities, and Mitigation .............................................. 4-8 4.5 Vulnerabilities and Risk Assessment ............................................................................. 4-10 4.6 Potential Mitigation Measures, Strategies, and Alternatives ......................................... 4-18 4.6.1 Prevention ............................................................................................................ 4-18 4.6.2 Property Protection .............................................................................................. 4-18 4.6.3 Public Education and Awareness ......................................................................... 4-19 4.6.4 Emergency Services ............................................................................................. 4-19 4.6.5 Structural Projects ................................................................................................ 4-20 4.7 Summary of Recommended Mitigation Measures, Strategies, and Alternatives .......... 4-20 5.0 SUMMER STORMS AND TORNADOES 5.1 Setting .............................................................................................................................. 5-1 5.2 Hazard Assessment .......................................................................................................... 5-1 5.3 Historic Record ................................................................................................................ 5-6 5.4 Existing Programs, Policies, Capabilities, and Mitigation .............................................. 5-8 5.5 Vulnerabilities and Risk Assessment ............................................................................. 5-10 5.6 Potential Mitigation Measures, Strategies, and Alternatives ......................................... 5-11 5.7 Summary of Recommended Mitigation Measures, Strategies, and Alternatives .......... 5-12 6.0 WINTER STORMS AND NOR'EASTERS 6.1 Setting .............................................................................................................................. 6-1 6.2 Hazard Assessment .......................................................................................................... 6-1 6.3 Historic Record ................................................................................................................ 6-2 6.4 Existing Programs, Policies, Capabilities, and Mitigation .............................................. 6-7 6.5 Vulnerabilities and Risk Assessment ............................................................................... 6-8 6.6 Potential Mitigation Measures, Strategies, and Alternatives ........................................... 6-9 6.6.1 Prevention .............................................................................................................. 6-9 MULTI-JURISDICTION HAZARD MITIGATION PLAN VALLEY COUNCIL OF GOVERNMENTS AUGUST 2012 TC-ii TABLE OF CONTENTS (Continued) 6.6.2 Property Protection ................................................................................................ 6-9 6.6.3 Public Education and Awareness ........................................................................... 6-9 6.6.4 Emergency Services ............................................................................................. 6-10 6.7 Recommended Actions 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