Samtrans Adaptation and Resilience Plan
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SAMTRANS ADAPTATION AND RESILIENCE PLAN February 2021 TABLE OF CONTENTS .............................................................................................................. i EXECUTIVE SUMMARY ......................................................................................................... vi Sea Level Rise Flooding and Inundation summary .................................................................. vii High Heat summary ................................................................................................................... ix 1 INTRODUCTION............................................................................................................. 1 1.1 VULNERABILITY ASSESSMENT OBJECTIVE ......................................................... 2 1.2 SAMTRANS FACILITY AND ASSET DESCRIPTION ............................................... 2 1.2.1 Fleet........................................................................................................................... 2 1.2.2 South Base ................................................................................................................ 8 2 SEA LEVEL RISE .......................................................................................................... 12 2.1 VULNERABILITY ASSESSMENT ............................................................................. 12 2.1.1 Methodology ........................................................................................................... 12 2.1.2 Exposure Analysis .................................................................................................. 16 2.1.3 Asset Sensitivity...................................................................................................... 34 2.1.4 Adaptive Capacity and Vulnerability Summary ..................................................... 37 2.1.5 Limitations .............................................................................................................. 38 2.2 ACTION ALTERNATIVES .......................................................................................... 38 2.2.1 North Base Action Alternatives .............................................................................. 40 2.2.2 South Base Action Alternatives .............................................................................. 43 2.2.3 Regional Adaptation Projects ................................................................................. 44 2.3 LIFECYCLE BENEFIT COST ANALYSIS ................................................................. 45 2.3.1 Socioeconomic and Environmental Impacts ........................................................... 47 2.4 PORTFOLIO OF ACTION ALTERNATIVES ............................................................. 49 3 HEAT ............................................................................................................................... 51 3.1 VULNERABILITY ASSESSMENT ............................................................................. 51 3.1.1 Methodology ........................................................................................................... 51 3.1.2 Facility Vulnerability .............................................................................................. 56 3.1.3 Fleet Vulnerability .................................................................................................. 57 3.1.4 Passenger Vulnerability .......................................................................................... 59 3.1.5 Representative Bus Stops ........................................................................................ 64 3.2 ACTION ALTERNATIVES .......................................................................................... 69 Page i 3.2.1 Facility Action Alternatives .................................................................................... 70 3.2.2 Fleet Action Alternatives ........................................................................................ 71 3.2.3 Passenger Action Alternatives ................................................................................ 72 3.3 PORTFOLIO OF ACTION ALTERNATIVES ............................................................. 74 4 CONCLUSION ............................................................................................................... 78 4.1 SLR Flooding and inundation ........................................................................................ 78 4.2 High Heat ....................................................................................................................... 78 4.3 Programmatic Approach to Climate Resilience ............................................................. 79 5 REFERENCES ................................................................................................................ 80 APPENDICES APPENDIX A ACTION ALTERNATIVES ....................................................................... A-1 A.1 SLR Action Alternatives .............................................................................................. A-2 A.2 High Heat Action Alternatives ..................................................................................... A-7 APPENDIX B NORTH BASE LIFECYCLE BENEFIT COST ANALYSIS ................. B-1 B.1 Approach ...................................................................................................................... B-1 B.2 Results .......................................................................................................................... B-7 APPENDIX C SUMMARY OF NEXT STEPS FOR RETAINED ACTION ALTERNATIVES ......................................................................................................... C-1 C.1 North Base SLR Action Alternatives ........................................................................... C-1 C.2 South Base SLR Action Alternatives ........................................................................... C-6 C.3 High Heat ..................................................................................................................... C-8 C.3.1 Future Shelter Design/Advertising Contract Considerations .............................. C-10 C.3.2 Custom Shelter Design Considerations .............................................................. C-12 APPENDIX D HIGH HEAT FIGURES AND REPRESENTATIVE BUS STOPS ....... D-1 D.1 Heat vulnerability by indicator ..................................................................................... D-1 D.2 Representative Bus Stop Locations .............................................................................. D-7 D.3 Typical Bus Shelters ..................................................................................................... D-8 D.4 Selected Bus Stop Location details .............................................................................. D-9 Page ii TABLES Table 1. Retained Action Alternatives for North and South Base ............................................... viii Table 2. Projected Temperature Increase ....................................................................................... ix Table 3. North Base Asset Summary .............................................................................................. 4 Table 4. North Base Site Observations ........................................................................................... 5 Table 5. North Base Site HVAC Observations ............................................................................... 6 Table 6. South Base Asset Summary .............................................................................................. 9 Table 7. South Base Site Observations ......................................................................................... 10 Table 8. South Base HVAC Observations .................................................................................... 11 Table 9. SLR Hazard Definitions .................................................................................................. 12 Table 10. SLR Scenarios ............................................................................................................... 15 Table 11. North Base Extent of Flooding in 2050 ........................................................................ 21 Table 12. North Base Extent of Flooding in 2100 ........................................................................ 22 Table 13. South Base Extent of Flooding in 2050 ........................................................................ 26 Table 14. South Base Extent of Flooding in 2100 ........................................................................ 30 Table 15. North Base Depth of Permanent Flooding in Tidal Range in 2050 .............................. 35 Table 16. North Base Depth of Permanent Flooding in Tidal Range in 2100 .............................. 35 Table 17. South Base Depth of Permanent Flooding in Tidal Range in 2100 .............................. 36 Table 18. Adaptation Approaches for SLR ................................................................................... 39 Table 19. Retained North Base Action Alternatives ..................................................................... 40 Table 20. Retained South Base Action Alternatives ..................................................................... 43 Table 21. Present Discounted Cost Savings (Loss) Compared to Baseline (No Action) Alternative....................................................................................................................................