MUNICIPIO DE SAN SEBASTIÁN PUERTO RICO HAZARD MITIGATION PL A N UPDATED (V4) M AY 2 0 1 8 Tt Job No. 100-PTR-T38177 Contract No. 2018-000428 Municipality of San Sebastián Puerto Rico Hazard Mitigation Plan Municipality of San Sebastián, Puerto Rico (Updated May 2018, V4) Prepared for: Hon. Javier Jiménez Pérez Mayor Municipality of San Sebastián P.O. Box 1603 San Sebastián, P.R. 00685 Prepared by: Tetra Tech, Inc. 251 Recinto Sur Street Old San Juan San Juan, PR 00901 TABLE OF CONTENTS 1.0 Introduction ................................................................................................................................... 1-1 1.1 Background ................................................................................................................................ 1-1 1.2 Purpose ...................................................................................................................................... 1-2 1.3 Authority .................................................................................................................................... 1-3 1.4 Organization of the Plan ............................................................................................................ 1-3 1.5 Plan Adoption ............................................................................................................................. 1-5 2.0 Community Profile ......................................................................................................................... 2-1 2.1 Administrative Divisions............................................................................................................. 2-2 2.2 Environment............................................................................................................................... 2-2 2.2.1 Geology and Soils ............................................................................................................... 2-2 2.2.2 Topography and Hydrology ................................................................................................ 2-2 2.2.3 Ecological Zones ................................................................................................................. 2-3 2.2.4 Climate ............................................................................................................................... 2-3 2.3 Population and Demographics ................................................................................................... 2-4 2.4 Economy, Employment and Industry ......................................................................................... 2-6 2.5 Housing ...................................................................................................................................... 2-7 3.0 Planning Process ............................................................................................................................ 3-1 3.1 Requirements for Planning Process ........................................................................................... 3-1 3.2 Description of the Hazard Mitigation Planning Process ............................................................ 3-2 3.3 Formation of a Hazard Mitigation Committee ........................................................................... 3-3 3.4 Public Involvement and Outreach ............................................................................................. 3-4 3.5 Public Participation and Community Workshops ...................................................................... 3-4 3.5.1 Hazard Mitigation Planning Committee and Community Workshop ................................ 3-5 3.5.2 Hazard Mitigation Planning Committee: Developing Mitigation Strategy ...................... 3-11 3.5.3 Hazard Mitigation Planning Committee: Preparing an Implementation Strategy ........... 3-11 3.6 Public Participation in the Plan Development, Review and Comments of the Plan ................ 3-12 3.6.1 How Neighboring Communities Were Involved .............................................................. 3-12 3.6.2 How Neighboring communities were given the opportunity to be involved in the planning process 3-15 3.6.3 Documentation of Invitation to Neighboring Communities, e.g. Adjacent Municipalities and Municipalities with Similar Hazards .......................................................................................... 3-16 i Hazard Mitigation Plan Municipality of San Sebastián, Puerto Rico May 2018, v4 3.6.4 Plan Availability, Public Review of the Draft Plan ............................................................ 3-18 3.7 Review of Existing Legislation, Plans and Reports ................................................................... 3-18 3.7.1 Federal Acts, Plans, Guidance .......................................................................................... 3-18 3.7.2 Puerto Ric Laws ................................................................................................................ 3-18 3.7.3 Puerto Rico Regulations ................................................................................................... 3-19 3.7.4 Integrated Hazard Assessment for the Island of Puerto Rico, 2002 ................................ 3-20 3.7.5 Municipal Ordinances, Plans, and Tools .......................................................................... 3-20 3.7.6 Capability Assessment and Incorporation of Plans and Technical Information .............. 3-22 3.7.7 Continued Public Involvement ......................................................................................... 3-23 4.0 Risk Assessment ............................................................................................................................. 4-1 4.1 44 CFR 201.6 Requirements for Risk Assessment ...................................................................... 4-1 4.2 Methodology AND TOOLS .......................................................................................................... 4-2 4.2.1 Uncertainties and Limitations ............................................................................................ 4-5 4.3 IDENTIFICATION OF HAZARDS ................................................................................................. 4-12 4.3.1 Hazard Selection and Prioritization .................................................................................. 4-16 4.3.2 HAZARD DESCRIPTION ..................................................................................................... 4-18 4.4 PROFILE OF HAZARDS .............................................................................................................. 4-21 4.4.1 HAZARD PROFILE: EARTHQUAKE GROUND SHAKING ...................................................... 4-22 4.4.2 HAZARD PROFILE: LIQUEFACTION ................................................................................... 4-28 4.4.3 Hazard Profile: Earthquake-Induced Landslide ................................................................ 4-28 4.4.4 Hazard Profile: High Wind ................................................................................................ 4-29 4.4.5 HAZARD PROFILE: RIVERINE FLOODING .......................................................................... 4-36 4.4.6 Rainfall-Induced Landslide ............................................................................................... 4-40 4.5 INVENTORY OF ASSETS ............................................................................................................ 4-44 4.6 ASSESSING VULNERABILITY ...................................................................................................... 4-48 4.7 LOSS ESTIMATES ...................................................................................................................... 4-71 4.8 UNDERSTANDING FUTURE LOSSES IN SAN SEBASTIÁN ........................................................... 4-72 4.8.1 SAN SEBASTIÁN DEVELOPMENT TRENDS ........................................................................ 4-74 4.8.2 ASSESSING VULNERABILITY OF FUTURE DEVELOPMENT ................................................. 4-91 4.8.3 IMPACT OF CLIMATE CHANGE AND RESILIENCE ............................................................ 4-101 5.0 Mitigation Strategy ........................................................................................................................ 5-1 5.1 Requirements for Mitigation Strategies .................................................................................... 5-1 ii Hazard Mitigation Plan Municipality of San Sebastián, Puerto Rico May 2018, v4 5.2 Mitigation Strategy .................................................................................................................... 5-1 5.2.1 GOALS AND OBJECTIVES .................................................................................................... 5-2 5.2.2 MUNICIPALITY OF SAN SEBASTIAN CAPABILITY ASSESSMENT .......................................... 5-3 5.2.3 MITIGATION TECHNIQUES ................................................................................................. 5-6 5.3 Mitigation Action Plan ............................................................................................................. 5-10 5.4 Administration of Actions ........................................................................................................ 5-11 5.5 Assessing Cost Effectiveness of Mitigation Actions ................................................................