TOWN OF WATERTOWN HAZARD MITIGATION PLAN 2019 UPDATE FINAL PLAN Approved by FEMA May 8, 2019 [This page intentionally left blank] ACKNOWLEDGEMENTS & CREDITS This plan was prepared for the Town of Watertown by the Metropolitan Area Planning Council (MAPC) under the direction of the Massachusetts Emergency Management Agency (MEMA) and the Massachusetts Department of Conservation and Recreation (DCR). The plan was funded by the Federal Emergency Management Agency’s (FEMA) Pre-Disaster Mitigation (PDM) Grant Program. MAPC Officers President, Keith Bergman, Town of Littleton Vice President, Erin Wortman, Town of Stoneham Secretary, Sandra Hackman, Town of Bedford Treasurer, Taber Keally, Town of Milton Executive Director, Marc Draisen, MAPC Credits Project Manager: Martin Pillsbury Mapping/GIS Services: Caitlin Spence, Massachusetts Emergency Management Agency Director: Samantha Phillips Department of Conservation and Recreation Commissioner: Leo Roy Watertown Local Hazard Mitigation Planning Team Robert Quinn Chief, Fire Department Gerald Mee Superintendent, Department of Public Works Matthew Shuman Town Engineer, Department of Public Works Steven Magoon Director, Community Development and Planning Department TOWN OF WATERTOWN HAZARD MITIGATION PLAN 2019 UPDATE I TOWN OF WATERTOWN HAZARD MITIGATION PLAN 2019 UPDATE II TABLE OF CONTENTS ACKNOWLEDGEMENTS & CREDITS.......................................................................... I LIST OF TABLES AND FIGURES ............................................................................... V SECTION 1: EXECUTIVE SUMMARY ........................................................................1 SECTION 2: INTRODUCTION ....................................................................................5 SECTION 3: PLANNING PROCESS & PUBLIC PARTICIPATION ....................... 11 SECTION 4: RISK ASSESSMENT ............................................................................. 17 SECTION 5: HAZARD MITIGATION GOALS........................................................ 65 SECTION 6: EXISTING MITIGATION MEASURES ................................................ 67 SECTON 7: STAOFTUS MITIGATION MEASURES FROM 2012 PLAN.............. 75 SECTION 8: HAZARD MITIGATION STRATEGY ................................................. 79 SECTION 9: PLAN ADOPTION AND MAINTENANCE…………….…………89 SECTION 10: LIST OF REFERENCES……………………………..……………91 APPENDIX A: LOCAL HAZARD MITIGATION TEAM MEETINGS………..…..93 APPENDIX B: HAZARD MAPPING…………………………………….…..…97 APPENDIX C: PUBLIC MEETINGS……………………………………….…..107 APPENDIX D: DOCUMENTATION OF PLAN ADOPTION……..….……..…117 APPENDIX E: DOCUMENTATION OF PLAN APPROVAL……..….……..…119 III of 120 TOWN OF WATERTOWN – HAZARD MITIGATION PLAN – 2019 UPDATE IV of 120 TOWN OF WATERTOWN – HAZARD MITIGATION PLAN – 2019 UPDATE LIST OF TABLES & FIGURES TABLES Table 1: Plan Review and Update Process .................................................................................................... 3 Table 2: Previous Federal/State Disaster Declarations ................................................................................. 5 Table 3: FEMA-Funded Mitigation Projects .................................................................................................... 7 Table 4: Watertown Characteristics .............................................................................................................. 8 Table 5: Watertown Public Meetings........................................................................................................... 13 Table 6: Hazard Risk Summary……………………………………………………………………....…….17 Table 7: Middlesex County Flood Events, 1996 to 2017 ............................................................................ 19 Table 8: Locally Identified Areas of Flooding.............................................................................................. 23 Table 9: Inventory of Dams in and Upstream of Watertown ....................................................................... 26 Table 10: Hurricane Records for Massachusetts, 1938 to 2012.................................................................. 26 Table 11: Enhanced Fujita Scale .................................................................................................................. 28 Table 12: Tornado Records for Middlesex County ...................................................................................... 28 Table 13: Nor’easter Events for Massachusetts, 1978 to 2015 ................................................................... 29 Table 14: Middlesex County Thunderstorm Events, 2006 to 2017 .............................................................. 30 Table 15: NESIS Categories ........................................................................................................................ 33 Table 16: Severe Winter Storm Records for Massachusetts ........................................................................ 34 Table 17: Heavy Snow Events and Impacts in Middlesex County, 2000 to 2017 ....................................... 34 Table 18: Hail Size Comparisons ................................................................................................................. 36 Table 19: Middlesex County Ice Storm Events, 2000-2017 ........................................................................ 36 Table 20: Richter Scale and Effects ............................................................................................................. 38 Table 21: Historical Earthquakes in Massachusetts or Surrounding Area ..................................................... 38 Table 22: Landslide Volume and Velocity ................................................................................................... 41 Table 23: Middlesex County Extreme Cold and Wind Chill Occurrences.................................................... 44 Table 24: Middlesex County Extreme Heat Occurrences............................................................................. 45 Table 25: Chronology of Major Droughts in Massachusetts ......................................................................... 47 Table 26: Town of Watertown, MA 2005 Land Use ................................................................................... 52 Table 27: Summary of Watertown Developments, 2008-2017 .................................................................. 54 Table 28: Future Development Sites in Hazard Areas ................................................................................. 55 Table 29: Critical Facilities and Relationship to Hazard Areas ................................................................... 57 Table 30: Estimated Damages from Hurricanes ........................................................................................... 61 Table 31: Estimated Damages from Earthquakes ........................................................................................ 62 Table 32: Estimated Damages from Flooding.............................................................................................. 63 Table 33: Existing Hazard Mitigation Measures in Watertown ................................................................... 71 Table 34: Status of Mitigation Measures from the 2012 Plan ..................................................................... 75 Table 35: Prioritization of Mitigation Measures........................................................................................... 82 Table 36: Recommended Hazard Mitigation Measures............................................................................... 84 V of 120 TOWN OF WATERTOWN – HAZARD MITIGATION PLAN – 2019 UPDATE FIGURES Figure 1: Six-Step Planning Process ............................................................................................................. 11 Figure 2: USGS Flow Gage Data for the Assabet River, March 2010 ........................................................ 21 Figure 3: Aerial View of the Watertown Dam ............................................................................................. 25 Figure 4: State of Massachusetts Earthquake Probability Map ................................................................... 40 Figure 5: Massachusetts Wildfires, 2001 to 2009....................................................................................... 43 Figure 6: Wind Chill Temperature Index and Frostbit Risk .......................................................................... 44 Figure 7: Heat Index Chart .......................................................................................................................... 45 Figure 8: Statewide Drought Levels using SPI Thresholds, 1850 to 2012 .................................................... 47 Figure 9: Massachusetts Drought Status, December 2016…………………………………………….........49 Figure 10: Changes in Frequency of Extreme Downpours, 1948 – 2011…………………………….....…51 Figure 11: Extreme Heat Scenarios……………………………………..…………………………...……..51 Figure 12: Watertown Magnitude 7 Earthquake Losses by Occupancy Type……………….….…………62 Figure 13: Watertown 500-Year Flood Losses by Occupancy Type……………………………………....63 VI of 120 TOWN OF WATERTOWN – HAZARD MITIGATION PLAN – 2019 UPDATE [This page intentionally left blank] VII of 120 TOWN OF WATERTOWN – HAZARD MITIGATION PLAN – 2019 UPDATE SECTION 1: EXECUTIVE SUMMARY Hazard Mitigation planning is a proactive effort to identify actions that can be taken to reduce the dangers to life and property from natural hazard