Groundwater inundation hazards and socioeconomic impacts due to sea-level rise across the California coast

This project is one of 24 research projects totaling $6 million in funding through the California Ocean Protection Council's Proposition 84 Competitive Grants Program, initiated in 2018. Learn more.

Project Title: Groundwater inundation hazards and socioeconomic impacts due to sea-level rise across the California coast  

PI: Patrick Barnard, U.S. Geological Survey  

Project Description: 

Coastal communities need a comprehensive assessment of future hazards to mitigate and adapt to the effects of climate change. Coastal erosion, cliff retreat, and storm/sea-level rise (SLR)-induced overland flooding are being addressed through the state-supported Coastal Storm Modeling System (CoSMoS). However, SLR-driven coastal hazards associated with groundwater, such as inundation and salt water intrusion, have not been assessed across the state, despite the fact that investigations of a few pilot areas have shown that local impacts can be severe in some communities.  

This work will project the exposure of coastal communities across the entire State of California, including San Francisco Bay, to SLR-driven groundwater inundation, whereby low-lying areas are subject to permanent flooding as the water table rises with sea level and intersects the land surface. This climate change-driven coastal hazard is not regularly planned for and has already been shown to pose a major risk in certain regions decades before overland flooding due to SLR and storms become more dominant. Because engineering approaches to mitigating SLR-driven overland flooding will not affect groundwater inundation, assessment of this risk across the State of California and its 26 million coastal residents is an essential step for communities to understand and plan for the full impacts of climate change.  

This project will perform sophisticated numerical modeling that will produce maps of coastal zone groundwater inundation and shoaling for all of California across the full range of the state’s sea-level rise guidance scenarios. These model projections will be available for public download to support community-scale, climate adaptation planning, via the interactive web tool, Our Coast Our Future (OCOF: www.ourcoastourfuture.org). Groundwater exposure projections will be translated into socioeconomic impacts and made accessible on the Hazard Exposure Reporting and Analytics (HERA) web tool (https://www.usgs.gov/apps/hera/). By the conclusion of this study, the entire state of California will have consistent, robust projections of the full suite of coastal hazards expected over the next century, including overland flooding and beach/cliff erosion due to storms and sea level developed within CoSMoS, and groundwater inundation and shoaling, all at a scale designed to support local planning, and served up together on the widely used OCOF and HERA web tools.  

Project Timeline: 

This is a 2-year project that would end in December of 2020.