Critical Infrastructure at Risk: Sea Level Rise Planning Guidance for California’s Coastal Zone

In August 2021, the California Coastal Commission (CCC), one of California’s three coastal management agencies, issued the Critical Infrastructure at Risk: Sea Level Rise Planning Guidance for California’s Coastal Zone. The guidance serves as an advisory document for the state and local governments, asset managers, and stakeholders in California to update plans and policies for critical transportation and water infrastructure to adapt to sea-level rise and flooding. The guidance is based on different studies held to be the best available science on sea-level rise in California, which includes a projection of a 6-10 feet of sea-level rise by 2100. The guidance can serve as a forward-looking example for other states and local governments on how to plan for climate impacts to these types of infrastructure.

California has a $44 billion ocean-based economy, with 70 percent of residents living in coastal counties and millions of people visiting the state annually. The state’s coastal economy is supported by its interconnected infrastructure system built near California’s coast, which is increasingly susceptible to the adverse impacts of sea-level rise. California’s existing infrastructure was not designed to be resilient to climate change and sea-level rise, prompting CCC to launch a series of studies on sea-level rise along California’s coast that led to the development of the guidance.

The guidance has six chapters. Chapter 1 is an introduction, which gives an overview of the purpose of this document and lays out its limited scope and focus for critical transportation and water infrastructure. Chapter 2 provides background on sea-level rise planning, which discusses different tools used to analyze sea-level rise and the relevant regulatory framework in California for state and local policymakers and asset managers. Chapter 3 presents the challenges of sea-level rise planning for critical infrastructure. Chapter 4 presents key considerations for adaptation planning. Chapter 5 and 6 propose a range of potential adaptation strategies and tips for transportation and water infrastructure, respectively, building on the key considerations in Chapter 4.

In Chapter 3 specifically, CCC recognizes the unique characteristics of critical infrastructure, such as its size, cross-jurisdictional nature, and the vital role infrastructure plays in providing public services. To address these challenges, in Chapter 4, CCC provides five key considerations that policymakers and infrastructure planners may consider in developing adaptation plans and strategies for critical coastal infrastructure:

  • Coordinated Planning: This involves coordination among state agencies, local governments, regional planning bodies, asset managers, coastal communities, stakeholders, and other interested parties in the complex process of sea-level adaptation planning.
  • Environmental Justice: This involves public involvement and the participation of environmental justice communities who often experience disproportionate environmental burdens, are more vulnerable to adverse impacts, and often lack access to decision-making processes.                                 
  • Phased Adaptation: This allows asset managers to undertake adaptation incrementally to allow time for long-term planning and identify funding sources.                            
  • Adaptation Costs and Funding: This requires thinking proactively to identify potential funding sources that can be used to support adaptation planning costs and reducing damages to critical infrastructure assets. 
  • Nature-Based Adaptation Strategies: This encourages the use of ecological and physical strategies and processes — instead of only hard infrastructure approaches — to protect the built, inland, or backshore environment while preserving coastal resources.  

The above mentioned key considerations are then elaborated on in the context of potential adaptation strategies planners and policymakers may evaluate for transportation infrastructure in Chapter 5 and water infrastructure in Chapter 6 as follows:

Adaptation Strategies for Transportation Infrastructure

  • Realignment: Moving at-risk transportation infrastructure inland to avoid coastal hazards associated with sea-level rise. This can help to ensure the long-term safety of infrastructure while avoiding the coastal resource impacts that would occur if the infrastructure is maintained in place.
  • Shoreline Protective Devices: Often halt or slow natural shoreline processes, such as erosion retaining sediment that would otherwise have normally contributed to beach formation. These devices may be a reasonable short- to mid-term adaptation strategy when they are the least environmentally damaging alternative in the context of phased adaptation. 
  • Nature-Based Adaptation Strategies: These approaches for coastal protection help to conserve and enhance natural coastal processes and ecological benefits while protecting inshore or inland areas. 

Adaptation Strategies for Water Infrastructure

  • Expected Life of Water Infrastructure Components: Water infrastructure will necessitate long-term planning that considers the interplay of different component facilities with different expected useful life and design. Planning should also consider necessary upgrades of older facilities to incorporate sea-level rise science and phased adaptation planning.  
  • Designing for Coastal Resource Protection: This will involve the design, maintenance, repair, and long-term resilience of water infrastructure to continuously provide water supply, reduce flood risks, incur collection, and treat wastewater to protect public health and the environment. 
  • Nature-Based Adaptation Strategies for Water Infrastructure: This can include hybrid armoring approaches in which natural systems are restored or enhanced in combination with constructed features, such as marsh sills, buried revetments and cobble berms. 

The document contains several appendices with additional materials that can be used to implement different parts of the guidance including: 

  • Appendix B: Model planning and policy language for transportation and water infrastructure.
  • Appendix C: The six steps for sea-level rise adaptation planning recommended by CCC. 
  • Appendix E: Case studies of how jurisdictions in California are addressing sea-level rise for critical transportation and water infrastructure and incorporating the key considerations recommended by the CCC, which can serve as peer-learning examples for others. 
  • Appendix F: Examples of nature-based adaptation strategies for California.
  • Appendix G: Information on the cost savings of adaptation and hazard avoidance measures to drive and support more proactive adaptation actions. 


The guidance is considered a “next step” for California in sea-level rise policy guidance because it builds on previous work by the CCC. The guidance is based on the findings under the State of California Sea-Level Rise Guidance (OPC 2018) and the report entitled, Rising Seas in California: An Update on Sea-Level Rise Science, which the state considers to be the best available science in California projecting 6-10 feet of sea-level rise by 2100. These projections are intended to guide planning decisions for the siting and design of critical infrastructure. In addition, in May 2020, the state adopted the Making California’s Coast Resilient to Sea-Level Rise: Principles for Aligned State Action, calling for adaptation plans to address a minimum target of 3.5 feet of sea-level rise in the next 30 years in California.

Publication Date: August 2021

Related Organizations:

  • California Coastal Commission

Related Resources:


Resource Category:

Resource Types:

  • Case study
  • Plans (other)
  • Policy analysis/recommendations

States Affected:


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