STAFF REPORT Living with a Rising Bay: Vulnerability and Adaptation in San Francisco Bay and on its Shoreline Approved on October 6, 2011 SAN FRANCISCO BAY CONSERVATION AND DEVELOPMENT COMMISSION 50 California Street, Suite 2600 San Francisco, CA 94111 Information: (415) 352-3600 Fax: (415) 352-3606 Web site: http://www.bcdc.ca.gov TABLE OF CONTENTS ACKNOWLEDGMENTS................................................................................................................................v EXECUTIVE SUMMARY.............................................................................................................................. 1 The Vulnerability Assessment ..................................................................................................... 2 1. Shoreline Development ............................................................................................................ 2 2. The Bay........................................................................................................................................ 5 3. Governance................................................................................................................................. 6 Adaptation Strategies.................................................................................................................... 7 Proposed Bay Plan Amendment ................................................................................................. 8 CHAPTER 1. CAUSES OF SEA LEVEL RISE........................................................................................... 11 The Greenhouse Effect and Global Warming.......................................................................... 11 Emissions Scenarios ....................................................................................................... 12 The California Climate Action Team........................................................................... 13 Bay Area GHG Contributions....................................................................................... 15 Sea Level Rise ............................................................................................................................... 17 Ice-Sheet Melting and Uncertainty .............................................................................. 19 Sea Level Rise Scenarios ............................................................................................................. 20 Sea Level Rise and Extreme Events ............................................................................. 22 BCDC Policy Analysis.................................................................................................... 23 Vulnerability Assessment........................................................................................................... 25 Vulnerability from Subsidence ..................................................................................... 26 Shoreline Protection .................................................................................................................... 41 Summary and Conclusions ........................................................................................................ 44 CHAPTER 2. SHORELINE DEVELOPMENT............................................................................................. 47 Residential Land Use .................................................................................................................. 48 Residents with Increased Vulnerability ...................................................................... 50 Schools and Emergency Services ................................................................................. 57 Commercial and Industrial Land Use ...................................................................................... 57 Airports ............................................................................................................................ 57 Ports .................................................................................................................................. 59 Water-Related Industry ................................................................................................. 62 Indirect Effects of Sea Level Rise............................................................................................... 63 Public Health Impacts of Climate Change............................................................................... 63 Other Shoreline Land Uses, Infrastructure and Institutions ................................................. 64 Wastewater Treatment Facilities .................................................................................. 64 Flood Control Channels................................................................................................. 65 Contaminated Lands...................................................................................................... 65 Pipelines and Transmission Lines................................................................................ 65 i The Regional Transportation Network .................................................................................... 66 Major Roadways and Highways .................................................................................. 67 Rail Network ................................................................................................................... 69 Waterfront Parks and Beaches................................................................................................... 71 Public Access Required by BCDC ............................................................................................. 72 Summary and Conclusions ........................................................................................................ 75 CHAPTER 3. THE SAN FRANCISCO BAY ECOSYSTEM ....................................................................... 79 Sea Level Rise in the Bay Ecosystem ........................................................................................ 80 Constraints to Wetland Adaptation............................................................................. 81 Salinity Change in Tidal and Subtidal Habitats......................................................... 83 Other Water Quality Impacts..................................................................................................... 86 Invasive and Migrant Species .................................................................................................... 87 Threat of Extinction ..................................................................................................................... 88 Shoreline Protection Impacts ..................................................................................................... 90 Ecological Consequences of a Tidal Barrage .............................................................. 90 Watershed Land Use ................................................................................................................... 92 Restoration and Adaptive Management .................................................................................. 93 Suisun Marsh................................................................................................................... 95 North Bay......................................................................................................................... 95 Central Bay ...................................................................................................................... 96 South Bay ......................................................................................................................... 98 Summary and Conclusions ...................................................................................................... 100 CHAPTER 4. GOVERNANCE: WHAT BCDC AND LOCAL JURISDICTIONS CAN DO ....................... 103 The Governance Landscape ..................................................................................................... 103 The Commission’s Jurisdiction and Authority ..................................................................... 106 The Commission’s Jurisdiction................................................................................... 107 The Commission’s Permit Authority......................................................................... 107 Salt Ponds and Managed Wetlands ........................................................................... 108 The 100-Foot Shoreline Band ...................................................................................... 109 Existing Bay Plan Policies Pertaining to Sea Level Rise.......................................... 109 The Public Trust Doctrine and Takings..................................................................... 110 Needs Assessment for Local Jurisdictions ............................................................................. 112 Statewide Survey .......................................................................................................... 113 Summary and Conclusions ...................................................................................................... 116 CHAPTER 5. ADAPTATION STRATEGIES FOR SAN FRANCISCO BAY AND THE SHORELINE .... 119 Adaptation Planning Considerations ..................................................................................... 119 Adaptation Planning Strategies.................................................................................. 120 Adaptive Management ................................................................................................ 121 Ecosystem-Based Management .................................................................................. 121 Integrating Mitigation and Adaptation..................................................................... 121 Adaptation Planning Framework ........................................................................................... 122 Vulnerability and Risk ................................................................................................. 123 Adaptation Strategies for San Francisco Bay and its Shoreline .......................................... 124 ii 1. Shoreline Development ........................................................................................................ 124 Risk Assessments and Adaptive Management Plans ............................................. 125 Evaluating Project Proposal ........................................................................................ 125 Safety of Fills ................................................................................................................. 126 Shoreline Protection ..................................................................................................... 126 High Water Level Metric ............................................................................................. 127 Public Access ................................................................................................................. 128 2. Bay Ecosystem ........................................................................................................................ 128 Tidal Marshes and Tidal Flats .................................................................................... 129 3. Governance ............................................................................................................................. 130 Regional Strategy .......................................................................................................... 131 Adaptation Tools for Local Government .................................................................. 134 Summary of Proposed Bay Plan Amendment ...................................................................... 140 Conclusion .................................................................................................................................. 141 APPENDIX A: Methods for Developing Data ...................................................................................... 143 References Cited ..................................................................................................................................... 145 FIGURES Figure 1.1 U.S. Contribution to Global CO2 Emissions (per Capita) ................................................ 14 Figure 1.2 Bay Area Contribution to CO2 Emissions (per Capita) .................................................... 15 Figure 1.3 Bay Area GHG Sources ........................................................................................................ 16 Figure 1.4 Sea Level Rise in San Francisco Bay .................................................................................. 17 Figure 1.5 Long Term Trend in Sea Level Rise .................................................................................... 18 Figure 1.6 Bay Area Land Uses and Subregions ................................................................................. 24 Figure 1.7 South Bay: Shoreline Areas Potentially Exposed to Sea Level Rise ............................... 28 Figure 1.8 Central Bay South: Shoreline Areas Potentially Exposed to Sea Level Rise ................. 29 Figure 1.9 Central Bay West Shore: Shoreline Areas Potentially Exposed to Sea Level Rise ................................................................................................................... 30 Figure 1.10 Central Bay East Shore: Shoreline Areas Potentially Exposed to Sea Level Rise ...................................................................................................................... 31 Figure 1.11 Central Bay: Shoreline Areas Potentially Exposed to Sea Level Rise .......................... 32 Figure 1.12 Central Bay North: Shoreline Areas Potentially Exposed to Sea Level Rise .............. 33 Figure 1.13 Petaluma River: Shoreline Areas Potentially Exposed to Sea Level Rise ................... 34 Figure 1.14 Napa River: Shoreline Areas Potentially Exposed to Sea Level Rise .......................... 35 Figure 1.15 San Pablo Bay/Carquinez Straits: Shoreline Areas Potentially Exposed to Sea Level Rise .................................................................................................. 36 Figure 1.16 Grizzly Bay: Shoreline Areas Potentially Exposed to Sea Level Rise .......................... 37 Figure 1.17 Honker Bay: Shoreline Areas Potentially Exposed to Sea Level Rise ......................... 38 Figure 1.18 Suisun Marsh: Shoreline Areas Potentially Exposed to Sea Level Rise ...................... 39 Figure 1.19 Comparison of Current 100-year High Water Event and Average High Tide at Mid-Century ................................................................................................ 40 Figure 1.20 Typical Section: Subsided Land with Structural Shoreline Protection ....................... 41 Figure 1.21 Typical Section: Urban Shoreline with Bulkhead ........................................................... 42 Figure 1.22 Typical Section: Wetlands and Levees ............................................................................. 43 Figure 2.1 South Bay Priority Development Areas Potentially Exposed to Seal Level Rise ......... 53 iii Figure 2.2 Central Bay North Priority Development Areas Potentially Exposed to Seal Level Rise ............................................................................... 54 Figure 2.3 Central Bay North Low Income Residential Areas Potentially Exposed to Seal Level Rise ............................................................................... 55 Figure 2.4 Central Bay South Low Income Residential Areas Potentially Exposed to Seal Level Rise ............................................................................... 56 Figure 2.5 Central Bay West Shore Transportation Network and Shoreline Priority Use Areas Potentially Exposed to Seal Level Rise ............................................. 60 Figure 2.6 Central Bay Transportation Network and Shoreline Priority Use Areas Potentially Exposed to Seal Level Rise ............................................................................... 61 Figure 2.7 Grizzly Bay Transportation Network and Shoreline and Priority Use Areas Potentially Exposed to Seal Level Rise ............................................................................... 68 Figure 2.8 Typical Section: Highway Adjacent to the Bay .................................................................. 69 Figure 2.9 Typical Section: Highway or Rail Line through Wetlands .............................................. 70 Figure 2.10 Typical Section: Public Access ............................................................................................ 72 Figure 2.11 Public Access Central Bay North Potentially Exposed to Seal Level Rise ................... 73 Figure 2.12 Public Access Central Bay West Shore Potentially Exposed to Seal Level Rise .......... 74 Figure 3.1 Salinity Change in San Francisco Bay ................................................................................. 84 Figure 3.2 Changes to Freshwater Inflow to the Estuary .................................................................... 85 Figure 3.3 Estuary Migration .................................................................................................................. 89 Figure 3.4 Suisun Marsh Habitats Potentially Exposed to Sea Level Rise ....................................... 94 Figure 3.5 North Bay Habitats Potentially Exposed to Sea Level Rise ............................................. 96 Figure 3.6 Central bay Habitats Potentially Exposed to Sea Level Rise ........................................... 97 Figure 3.7 South Bay Habitats Potentially Exposed to Sea Level Rise .............................................. 98 Figure 4.1: Top Coastal Zone Management Challenges ................................................................... 113 Figure 5.1 Climate Change Adaptation Planning Model ................................................................. 122 TABLES Table 1.1. Projected Global Average Surface Warming at the End of the Century ........................ 13 Table 1.2. CO-CAT Sea Level Rise Scenarios using 2000 as the Baseline ......................................... 21 Table 2.1 Residential Acreage Potentially Exposed to More Flooding or Permanent Inundation due to Seal Level Rise .................................................................... 49 Table 2.2 Summary of Land Uses Potentially Exposed to Flooding or Permanent Inundation due to Sea Level Rise .......................................................................................... 63 Table 2.3 Summary of Shoreline Vulnerabilities .................................................................................. 76 Table 3.1 Summary of Vulnerabilities in the Bay Ecosystem ............................................................. 99 Table 4.1 Summary of Vulnerabilities in Bay Area Governance Systems ...................................... 116 Table 5.1 Summary of Adaptation Strategies ..................................................................................... 138 BOXES Box 1.1 Definitions .................................................................................................................................... 23 Box 2.1 The FOCUS Program .................................................................................................................. 50 Box 3.1 Shoreline Management and Watershed Management Planning ......................................... 93 Box 4.1 Hazard Mitigation Planning in the Bay Area ....................................................................... 105 Box 5.1 Adaptive Management in the South Bay Salt Pond Restoration Project .......................... 120 Box 5.2 Regional Problems, Regional Solutions: A History of Regional Action on Public Safety and Environmental Issues in the Bay Area ................................................... 132 iv ACKNOWLEDGMENTS This report assesses the vulnerability of San Francisco Bay and its shoreline to the impacts of climate change, identifies information needs for future vulnerability assessments, and suggests near-term and long-term strategies to address climate change impacts. Where feasible, those strategies are incorporated into recommended findings and policy revisions to the San Francisco Bay Plan. The preparation of this report was supported by a grant from the National Oceanographic Atmospheric Administration, Office of Coastal Resource Management. The California Energy Commission’s Public Interest Energy Research Program (PIER) provided funding to the United States Geologic Survey (USGS) to develop the GIS data on which this analysis was based. We are grateful to Guido Franco at PIER for his foresight in identifying climate change information needs and his guidance in approaching this project. We thank Noah Knowles for developing the GIS data, making it available for our analysis, and making himself available to review and comment on our approach. PIER, with support from the Metropolitan Transportation Commission, provided funding to the Pacific Institute to assess the cost of sea level rise using the data provided by USGS. The Pacific Institute’s report provided vital information for our assessment. We thank Peter Gleick and the staff at the Pacific Institute, Heather Cooley and Matthew Heberger, for coordinating with us throughout the writing of this report. Special thanks to our technical and agency reviewers and citizen’s advisory committee members for taking the time to provide tremendously helpful comments and suggestions: John Andrew from the Department of Water Resources, Amanda Babson from the U.S. Environmental Protection Agency, Liz Brisson from the Metropolitan Transportation Commission, Bob Brown of our Citizen’s Advisory Committee, John Callaway from University of San Francisco, Dan Cayan from USGS and Scripps, Josh Collins from the San Francisco Estuary Institute, Lesley Ewing from the California Coastal Commission, Lara Hansen from EcoAdapt, Mike Josselyn of our Citizen’s Advisory Committee, Jeremy Lowe and Phil Williams from Philip Williams and Associates, Bruce Riordan from the Joint Policy Committee, Michele Rodriquez from Planning Sustainable Communities, and Barbara Salzman of our Citizen’s Advisory Committee. Special thanks to our intern Javier del Castillo for lending his expertise and time to sketch the typical shoreline cross-sections that appear throughout the report. Finally, we gratefully acknowledge the members of the public, agencies and organizations who provided invaluable feedback through the public hearing process to refine the content of the report and strengthen the foundation on which the Commission’s Bay Plan policies rest. v vi Executive Summary San Francisco Bay is a national treasure that helps sustain the economy of the western United States, provides wonderful opportunities for recreation, nourishes fish and wildlife, provides unparalleled scenic splendor, and in countless other ways enriches our lives. The Bay is the principal visual icon of our region, whether seen when traveling by car or rail along the shoreline, landing at an airport, strolling along the shoreline, or watching the fog stream in on a summer’s day. Managing the threats to the Bay and shoreline development from sea level rise st will be one of the defining challenges we face in the 21 century. A richly varied composite of urbanization and nature exists in and around San Francisco Bay. Urban waterfronts, critical habitat areas, industrial areas and residential neighborhoods coexist within walking distance of each other. Overlaid on these shoreline places is a vital system of public infrastructure, including freeways, seaports, railroads and airports, which knit the shoreline communities together and connect them to the rest of the region, California and the world. This tapestry helps make the beauty of the Bay Area world-renowned and underpins its economy, the health of its natural systems and the quality of life of its inhabitants. Over the past 150 years, the productive use of the Bay’s shoreline has become the cornerstone of the region’s prosperity and forged an inseparable bond between the people of the Bay Area and the Bay itself. The nine-county San Francisco Bay Area is home to approximately seven million people making the Bay one of the world’s most urbanized estuaries. Climate change has the potential to dramatically impact the economy, environment and quality of life in the Bay Area. Changes in personal behavior, institutional actions, and government policies are needed to reduce greenhouse gas emissions, moderate temperature increases attributed to global warming, and mitigate climate change. To some extent, the choice to alter lifestyles and institutional priorities now will reduce the degree to which the world must adapt to the effects of climate change. However, no matter how effectively the world reduces greenhouse gas emissions, oceans have already warmed, sea levels are already rising at accelerated rates, and are likely to accelerate further. Therefore, while mitigating climate change by reducing greenhouse gas emissions is essential, adapting to climate change and its impacts is unavoidable. Local governments and land management agencies already face challenging issues, such as dealing with competing land uses, ensuring that adequate shoreline areas remain available for water-dependent uses, upgrading aged infrastructure, reducing traffic congestion, protecting 1 habitat and water quality, maintaining flood protection, and providing public shoreline access. Shoreline vulnerability assessments can help government agencies and the public understand how existing planning and management challenges will be exacerbated by climate change and assist in developing strategies for dealing with these challenges. The Vulnerability Assessment Two sea level rise projections were selected as the basis for the vulnerability assessment in this report: a 16-inch (40 cm) sea level rise by mid-century and a 55-inch (140 cm) rise in sea level by the end of the century. When BCDC initiated its effort to amend the Bay Plan to address climate change in 2009, the State of California was still in the process of formulating statewide policy direction for adapting to sea level rise. In 2010 the Coastal and Ocean Working Group of the California Climate Action Team (CO-CAT) developed a Sea Level Rise Interim Guidance document that advises the use of projections (relative to sea level in 2000) for the state that range from 10 to 17 inches by 2050, 17 to 32 inches by 2070, and 31 to 69 inches at the end of the century (based on work by Vermeer and Ramstorf, 2009). This document was endorsed by a resolution of the California Ocean Protection Council in 2011. The projections used in BCDC’s report fall within the ranges suggested by the CO-CAT’s Sea Level Rise Interim Guidance document. The CO-CAT has recognized that it may not be appropriate to set definitive sea level rise projections, and, based on a variety of factors, state agencies may use different sea level rise projections. Although the CO-CAT values are generally recognized as the best science-based sea level rise projections for California, scientific uncertainty remains regarding the pace and amount of sea level rise. Moreover, melting of the Greenland and Antarctic ice sheets may not be reflected well in current sea level rise projections. The interim guidance will be updated consistent with the National Academy of Sciences sea level rise assessment report, expected in 2012, and other forthcoming studies. Using the two sea level rise projections, the vulnerability assessment focused on three planning areas or systems: shoreline development, the Bay ecosystem, and governance. Key sectors within each system, such as land uses or subregions of the Bay, were used to assess their sensitivity, adaptive capacity and, ultimately, their vulnerability. 1. Shoreline Development Residents, businesses and entire industries that currently thrive on the shoreline will be at risk of flooding by the middle of the century, and probably earlier, if nothing is done to protect, elevate or relocate them. A 16-inch rise (relative to sea level in 2000) would potentially expose 2