A NOAA-supported science team is collecting field observations at sites along 300 miles of beaches and dunes on the California coast to understand how they are changing under sea level rise to better predict the future conditions. In total, California has 1,200 miles of beaches and coastal wetlands which are increasingly threatened by sea level rise and more frequent, intense storms, resulting in habitat loss and damage to infrastructure from subsequent erosion and inundation. However, if carefully planned, these habitats also have the potential to become nature based solutions that mitigate flood damage and provide additional ecological and economic benefits, such as recreational value.
Models that predict beach width and shoreline position in California currently perform relatively well (i.e., CoSMoS-Coast), though these models currently lack reliable prediction of how the sand dune height and shape, behind the beach, is likely to change over years to decades (i.e., dune evolution). Predicting dune evolution is important to ensure we have time to plan and acquire resources to foster dunes that will protect our coasts. Existing dune models were developed with data from coastlines around the world that are much different than the California coast and when applied in California, they produce inconsistent results. By gathering observations in California that quantify how physical beach and dune characteristics change over long time periods, dune evolution models can be trained to account for these past changes and then used to predict future California dune and beach change. The teams will complete numerical modeling improvements at key representative locations across 300 miles of the north-central California coast. The project team will also work with regional experts to identify representative coastal habitats and management challenges in the region. They will inform coastal planning and project challenges by quantifying shoreline response to the impacts of sea level rise under different adaptation scenarios and project designs.
The research team is specifically conducting uncrewed aerial systems (UAS) field surveys to collect high resolution data that includes beach topography and imagery at seven sites. The team will utilize these datasets, along with data collected in 2023, to assess current conditions and track physical beach and dune change. The information is being made available immediately here for local project planning efforts. Dune change data collected within the Greater Farallones National Marine Sanctuary and across the state of California will inform the addition of a dune evolution model into CoSMoS-COAST, and numerical modeling of coastal management scenarios will continue over the course of the year. The physical beach and dune modeling will also enable modeling of ecological responses to sediment management interventions such as sediment augmentation and help to answer key questions about the ecological benefits of adaptation.
The project is led by Dr. Wendy Kordesch of the Greater Farallones Association (GFA) and Max Delaney of the Greater Farallones National Marine Sanctuary (GFNMS), and includes the following investigators: Sara Hutto, Sage Tezak, and Maria Brown of GFNMS; Dr. Sean Vitousek and Dr. Maya Hayden of USGS; Kriss Neuman and Dr. Matthew Reiter of Point Blue Conservation Science; Peter Allen and Kate Anderson of CA Coastal Commission; and Scott Williams and Arnica MacCarthy of Caltrans.
The project was supported in part by the NCCOS Effects of Sea Level Rise (ESLR) Program. For more information, visit the NCCOS project page.