TRAVIS COUNTY Hazard Mitigation Plan Update Mitigating Risk for a Safe, Secure, and Sustainable Future APA: August 29, 2017 For more information, visit our website at: www.traviscountytx.gov Written comments should be forwarded to: H2O Partners, Inc. P. O. Box 160130 Austin, Texas 78716 [email protected] www.h2opartnersusa.com TABLE OF CONTENTS SECTION 1 – INTRODUCTION Background .................................................................................................................................................... 1-1 Scope and Participation ................................................................................................................................. 1-2 Purpose .......................................................................................................................................................... 1-3 Authority ........................................................................................................................................................ 1-3 Summary of Sections ..................................................................................................................................... 1-4 SECTION 2 – PLANNING PROCESS Plan Preparation and Development ............................................................................................................... 2-1 Review of Existing Plans, Plan Integration, and Updates ............................................................................... 2-8 Timeline for Implementing Mitigation Actions ............................................................................................ 2-11 Stakeholder and Public Involvement ........................................................................................................... 2-11 SECTION 3 – COUNTY PROFILE Overview ........................................................................................................................................................ 3-1 Population and Demographics ..................................................................................................................... 3-10 Future Development ................................................................................................................................... 3-11 Economic Impact ......................................................................................................................................... 3-12 Existing and Future Land Use and Development Trends ............................................................................. 3-13 SECTION 4 – RISK OVERVIEW Hazard Identification .................................................................................................................................... 4-1 Natural Hazards and Climate Change ........................................................................................................... 4-4 Overview of Hazard Analysis ......................................................................................................................... 4-4 Hazard Ranking ............................................................................................................................................. 4-6 SECTION 5 – FLOOD Hazard Description ....................................................................................................................................... 5-1 Location ......................................................................................................................................................... 5-1 Extent .......................................................................................................................................................... 5-12 Historical Occurrences ................................................................................................................................ 5-15 Travis County | Hazard Mitigation Action Plan Update | Page 2 TABLE OF CONTENTS Probability of Future Events ....................................................................................................................... 5-20 Vulnerability and Impact ............................................................................................................................. 5-20 NFIP Participation ....................................................................................................................................... 5-24 NFIP Compliance and Maintenance ............................................................................................................ 5-26 Repetitive Loss ............................................................................................................................................ 5-27 SECTION 6 – WILDFIRE Hazard Description ....................................................................................................................................... 6-1 Location ......................................................................................................................................................... 6-2 Historical Occurrences ................................................................................................................................. 6-10 Extent .......................................................................................................................................................... 6-13 Probability of Future Events ....................................................................................................................... 6-23 Vulnerability and Impact ............................................................................................................................. 6-23 SECTION 7 – DROUGHT Hazard Description ....................................................................................................................................... 7-1 Location ......................................................................................................................................................... 7-2 Extent ............................................................................................................................................................ 7-4 Historical Occurrences .................................................................................................................................. 7-6 Probability of Future Events ......................................................................................................................... 7-8 Vulnerability and Impact ............................................................................................................................... 7-8 SECTION 8 – TORNADO Hazard Description ....................................................................................................................................... 8-1 Location ......................................................................................................................................................... 8-2 Extent ............................................................................................................................................................ 8-2 Historical Occurrences .................................................................................................................................. 8-5 Probability of Future Events ......................................................................................................................... 8-9 Vulnerability and Impact ............................................................................................................................... 8-9 Travis County | Hazard Mitigation Action Plan Update | Page 3 TABLE OF CONTENTS SECTION 9 – THUNDERSTORM WIND Hazard Description ....................................................................................................................................... 9-1 Location ......................................................................................................................................................... 9-1 Extent ............................................................................................................................................................ 9-2 Historical Occurrences .................................................................................................................................. 9-3 Probability of Future Events ......................................................................................................................... 9-8 Vulnerability and Impact ............................................................................................................................... 9-8 SECTION 10 – EXTREME HEAT Hazard Description ..................................................................................................................................... 10-1 Location ....................................................................................................................................................... 10-1 Extent .......................................................................................................................................................... 10-2 Historical Occurrences ................................................................................................................................ 10-4 Probability of Future Events ......................................................................................................................