As sea levels rise and extreme storms become more frequent, communities are developing climate adaptation plans to protect housing, jobs, ecosystems, and infrastructure from flooding. However, these plans often neglect an important potential flood hazard – emergent groundwater. Shallow groundwater in coastal communities will rise as sea levels rise, increasing the risk of flooding communities from below. The threat of rising groundwater levels was identified by the Coastal Hazards Adaptation and Resiliency Group as a critical data gap in regional climate resilience planning. This proposal explores the links between sea level rise, precipitation, and the elevation of shallow groundwater in the San Francisco Bay Area so that adaptation plans can consider all potential flood hazards.

This project will be led by the Aquatic Science Center (ASC), a joint powers authority with a history of success in serving science for the public interest, along with multiple joint proposers consisting of Bay Area cities and counties who have identified rising groundwater as a potential problem within their jurisdiction, and have committed to providing staff time to support this project. The project will develop a series of shallow groundwater maps that consider the response to eight sea level rise scenarios (e.g., 12”, 24”, 36”, 48”, 52”, 66”, 84”, and 108”) for four of the nine Bay Area counties.

The sea level rise scenarios build upon and integrate with maps presented within the Adapting to Rising Tides (ART) Bay Shoreline Flood Explorer, which have been used extensively in the Bay Area to support local and regional adaptation planning. The sea level rise scenarios also pair with the current State guidance on sea level rise for the Bay Area. The project will also develop guidance for how to use the future-condition shallow groundwater mapping, addressing questions such as: how to use and understand the various data layers; how to consider the uncertainties within the data layers; how to update a sea level rise vulnerability and risk assessment to consider rising groundwater levels; and how to communicate this new potential flood risk to stakeholders.

This project will enhance, advance, and support existing efforts, including the ART Program’s Regional Bay Area Vulnerability Assessment, SFEI’s Adaptation Atlas, the University of Berkeley’s rapid regional groundwater assessment, and the University of Wyoming and the USGS’s modeling and research of the response of the shallow coastal groundwater layer to sea level rise. Subject matter experts from each of these efforts will serve on a Technical Advisory Committee to ensure that the best available science and information informs this work, that the resulting products are technically sound, and that the messaging and communication are effective throughout the project.

Dates: 
2020 to 2022
Funders: 
Programs and Focus Areas: 
Geographic Information Systems
Shoreline Resilience
Location Information