SANDAG Regional Transportation Infrastructure Sea Level Rise Assessment and Adaptation Guidance
SB1 Adaptation Planning Grant: Final Case Study
Summary
Over a two-year project period (spring 2018 - spring 2020), the San Diego Association of Governments (SANDAG) created the Regional Transportation Infrastructure Sea Level Rise Assessment and Adaptation Guidance (Adaptation Guidance). This document:
- Provides recommended updates for existing shoreline management policies to account for sea level rise;
- Examines potential sea level rise impacts to regional transportation infrastructure in San Diego County; and
- Presents a suite of sea level rise adaptation strategies and best practices for local jurisdictions to consider when updating or preparing relevant local plans or vulnerability assessments. Adaptation strategies include policies, potential projects (with an emphasis on natural infrastructure), and funding mechanisms.
SANDAG is the Metropolitan Planning Organization (MPO) for the San Diego region and, therefore, aligns its Regional Transportation Plan (RTP) and Sustainable Communities Strategy (SCS) (San Diego Forward: The 2015 Regional Plan) with the State's guidance. The RTP Guidelines (most recently adopted in 2017) and the California Transportation Plan 2040 both include policies that focus on adaptation of the transportation system and transportation infrastructure. Findings from the Adaptation Guidance will be incorporated into San Diego Forward: The 2021 Regional Plan.
Lead Agency and Partnerships
SANDAG served as the lead agency for this project and was responsible for preparation of the Adaptation Guidance. Key information for this project was obtained from vulnerability assessments and adaptation plans currently in process or recently completed by a number of coastal jurisdictions in the San Diego region, as well as information from the Port of San Diego, CalTrans District 11, and the San Diego Regional Airport Authority.
Drivers
This project has three main drivers:
- The State’s RTP Guidelines and the California Transportation Plan 2040, which include policies that focus on adaptation of the transportation system;
- SANDAG’s commitment to develop strategies that will enhance the region's ability to adapt to the consequences of climate change, which was identified as a continuing action in San Diego Forward: The 2015 Regional Plan; and
- The need to elevate work done at a local level to a regional decision-making body to promote sound and coordinated adaptation efforts, to best protect vulnerable portions of the regional transportation network.
The CalTrans SB1 Adaptation Planning Grant Program supported this project.
Engagement Process
Interviews were conducted with staff from local coastal jurisdictions to understand best practices and lessons learned in adaptation planning. Three public workshops were held to support this project. The first workshop was hosted by the Shoreline Preservation Working Group at SANDAG in October 2018, allowing elected officials from coastal communities to participate in a dialogue on coastal adaptation and to gain preliminary feedback on the proposed content of the Adaptation Guidance. After the initial draft of the Adaptation Guidance was completed, SANDAG held two additional public workshops to gather feedback from local staff members and elected officials. One workshop was held in the northern part of the region, and the other was held in the southern part of the region, ensuring that representatives from vulnerable coastal communities were engaged in this work effort. Feedback from these workshops was incorporated into the final Adaptation Guidance.
Climate Impact Area
A number of transportation facilities exist in or near the coastal areas of the San Diego region, including highways, bikeways, roadways, and both light and heavy rail infrastructure. These transportation facilities could be impacted by flooding under future sea level rise scenarios. The Adaptation Guidance examines potential sea level rise impacts to regional transportation infrastructure in San Diego County and includes a suite of adaptation strategies and best practices for consideration by local jurisdictions, thereby helping the region plan for and become more resilient to future sea level rise impacts.
Funding Source
This project was awarded $180,000 from the CalTrans SB1 Adaptation Planning Grant Program in December 2017. SANDAG provided an additional $23,321 in staff time to assist with this project. The total project budget was $203,321.
Research and Data
This project builds upon work conducted by a number of local jurisdictions and agencies. In preparing individual vulnerability assessments, most organizations utilized modeling information from the USGS’s Coastal Storm Modeling System (COSMOS 3.0), which provides a suite of sea level rise scenarios with four possible coastal storm conditions. Please see the Additional Resources section for links to this information. The Adaptation Guidance includes a complete list of references.
Challenges
Originally, the project team anticipated being able to combine vulnerability assessment data from existing studies that had been completed by local jurisdictions and agencies. However, no one sea level rise scenario was used universally. As such, SANDAG selected two scenarios representing probabilistic sea level rise projections for the years 2050 and 2100 and applied those scenarios to the entire San Diego coastline.
Outcomes
The main outcome of this project was the Adaptation Guidance. This document addresses future vulnerabilities to the regional transportation system and includes possible local and regional adaptation strategies that can be utilized in the future. Next steps include producing a Regional Adaptation Needs Assessment, encompassing needs related to climate impacts beyond sea level rise, and developing guidance and decision-making tools for local jurisdictions to prioritize adaptation strategies that are economically and equitably balanced.
Replicability
Preparation of the Adaptation Guidance required coordination and collaboration with local jurisdictions and agencies. This project could be replicated by another MPO or regional agency; however, this type of project requires sufficient information on local sea level rise vulnerability and adaptation to be combined into a single document.
Additional Resources
A number of local efforts contributed to the Adaptation Guidance. Many of these individual projects benefited from elements of the Resilient Coastlines Project of Greater San Diego, which provided support to a number of entities in the region.
Further Information
Please contact Sarah Pierce at 619-699-7312 or via email at sarah.pierce@sandag.org for additional information on this project.
