Santa Cruz County Coastal Climate Change Vulnerability Report
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Santa Cruz County Coastal Climate Change Vulnerability Report JUNE 2017 CENTRAL COAST WETLANDS GROUP MOSS LANDING MARINE LABS | 8272 MOSS LANDING RD, MOSS LANDING, CA Santa Cruz County Coastal Climate Change Vulnerability Report This page intentionally left blank Santa Cruz County Coastal Climate Change Vulnerability Report i Prepared by Central Coast Wetlands Group at Moss Landing Marine Labs Technical assistance provided by: ESA Revell Coastal The Nature Conservancy Center for Ocean Solutions Prepared for The County of Santa Cruz Funding Provided by: The California Ocean Protection Council Grant number C0300700 Santa Cruz County Coastal Climate Change Vulnerability Report ii Primary Authors: Central Coast Wetlands group Ross Clark Sarah Stoner-Duncan Jason Adelaars Sierra Tobin Kamille Hammerstrom Acknowledgements: California State Ocean Protection Council Abe Doherty Paige Berube Nick Sadrpour Santa Cruz County David Carlson City of Capitola Rich Grunow Coastal Conservation and Research Jim Oakden Science Team David Revell, Revell Coastal Bob Battalio, ESA James Gregory, ESA James Jackson, ESA GIS Layer support AMBAG Santa Cruz County Adapt Monterey Bay Kelly Leo, TNC Sarah Newkirk, TNC Eric Hartge, Center for Ocean Solution Santa Cruz County Coastal Climate Change Vulnerability Report iii Contents Contents Summary of Findings ........................................................................................................................ viii 1. Introduction ................................................................................................................................. 1 1.1. Background ................................................................................................................................... 1 1.2. Coastal Commission Guidance ...................................................................................................... 1 1.3. Geographic Scope of Study ........................................................................................................... 2 2. Community Profile ....................................................................................................................... 4 2.1. Setting and Climate ....................................................................................................................... 4 2.2. Culture and Industry ..................................................................................................................... 4 2.3. Historical Context .......................................................................................................................... 5 2.4. Demographics ............................................................................................................................... 5 2.5. Community Resources and Assets ................................................................................................ 5 3. Climate Science .......................................................................................................................... 14 3.1. Climate Change ........................................................................................................................... 14 3.2. Sea Level Rise Projections ........................................................................................................... 16 3.3. State guidance ............................................................................................................................. 17 3.4. Coastal Hazards from Sea Level Rise ........................................................................................... 17 3.5. Current Planning Landscape ....................................................................................................... 18 3.6. Previous Studies and Reports in the Region ............................................................................... 21 4. Vulnerability Assessment Methodology ..................................................................................... 24 4.1. Disclaimer: Hazard Mapping and Vulnerability Assessments ..................................................... 24 4.2. Coastal Hazard Processes ............................................................................................................ 25 4.3. Scenario Selection and Hazards .................................................................................................. 27 4.4. Modifications to ESA Hazard Models .......................................................................................... 28 4.5. Data Compilation ........................................................................................................................ 29 4.6. GIS Mapped Assets Used for Analysis ......................................................................................... 30 4.7. GIS Vulnerability Analysis Methods ............................................................................................ 32 Santa Cruz County Coastal Climate Change Vulnerability Report iv 4.8. Considerations Regarding New and Rebuilt Sea Walls ............................................................... 33 4.9. Economic Analysis and Adaptation Alternatives ........................................................................ 34 5. Combined Impacts of Coastal Climate Change ............................................................................ 37 5.1 Existing Vulnerabilities ................................................................................................................ 37 5.2 Future Hazards from Coastal Climate Change by Planning Horizon ........................................... 38 6. Vulnerabilities from Individual Coastal Hazards .......................................................................... 44 6.1 Section 1: Santa Cruz City Limit to Año Nuevo ........................................................................... 44 6.2 Section 2: 7th Ave to Capitola ..................................................................................................... 46 6.3 Section 3: Seacliff to Manresa Beach .......................................................................................... 48 6.4 Section 4: Pajaro Valley from Sunset Beach to the County Line ................................................. 49 6.5 Future Risks to Specific Assets .................................................................................................... 53 7. Economics of Future Climate Risks .............................................................................................. 59 7.1 Property valuation of vulnerable properties and infrastructure ................................................ 59 8. Adaptation Strategies Options .................................................................................................... 62 8.1 Adaptation Strategies by Coastal Hazard .................................................................................... 62 8.2 Strategies Listed Within Existing Plans ....................................................................................... 62 8.3 Adaptation Strategy Selection .................................................................................................... 65 8.4 Potential Strategies for Climate Adaptation in Santa Cruz County by Time Horizon ................. 66 9. Conclusion .................................................................................................................................. 73 Possible Next Steps ................................................................................................................................. 73 References and Resources ................................................................................................................. 75 List of Tables Table 1. Major Floods in Santa Cruz County, 1861 to Present ................................................................... 11 Table 2. Sea level rise scenarios selected for analysis ................................................................................ 28 Table 3. List of Assets Used in Analysis ....................................................................................................... 31 Table 4. Inventory of Existing Coastal Protection and Water Control Structures in Santa Cruz County .... 33 Table 5. Property valuation data sources for economic analysis ............................................................... 35 Table 6. Specific assets vulnerable to coastal climate change hazards ...................................................... 58 Table 7. Total Value (2016 dollars) of Unincorporated Santa Cruz County Properties at Risk ................... 60 Table 8. Coastal infrastructure vulnerable to 2030 hazard projections. .................................................... 66 Table 9. Coastal infrastructure vulnerable to 2060 hazard projections. ................................................... 69 Table 10. Coastal infrastructure vulnerable to 2100 hazard projections. ................................................. 71 Santa Cruz County Coastal Climate Change Vulnerability Report v List of Figures Figure 1. Geographic Scope of Coastal Climate Change Vulnerability Analysis ............................................ 3 Figure 2. The Greenhouse Effect................................................................................................................. 14 Figure 3. Flowchart for addressing sea level rise in Local Coastal Programs and other plans ................... 20 Figure 4. Sea