Coastal communities preparing for the next high tide
The beach trends study will be conducted by TerraCosta Consulting (Ron Flick and Adam Young) and the shoreline modeling and backshore characterization is being handled by Revell Coastal (David Revell) and Environmental Science Associates (Bob Battalio). USC Sea Grant is also working with the U.S. Geological Survey on outreach for the latest version of the USGS Coastal Storm Modeling System (CoSMoS) that applies to the entire Southern California Bight.
Predicting coastal flooding
The Sea Grant vulnerability report for the city was based on a pilot version of the USGS modeling system, called CoSMoS 1.0, which makes predictions of storm-induced coastal flooding based on a moderately severe storm that occurred in the region in January 2010. It models storm-driven sea level rise for two future climate scenarios, which can help emergency responders and coastal planners anticipate storm hazards and make plans to allocate resources to deal with them.
The Southern California version of CoSMoS 3.0 is in development now; some results are expected to be released in 2015 with the full suite of studies completed in summer 2016. Enhancements to the USGS program include models for long-term evolution of coastal environments, including sandy beaches and cliffs, models for discharge from rivers and long-term sediment supply to coastal waters.
Funding for CoSMoS 3.0 comes from the California Coastal Conservancy along with support from the Tijuana River National Estuarine Research Reserve and California Department of Fish & Wildlife. The updated CoSMoS project includes support from the Coastal Conservancy for USC Sea Grant to handle outreach to local communities.
“It’s our job to train planners and stakeholders from coastal communities to utilize the models,” Grifman said. “Our job now is ‘capacity building’ in the Southern California Bight.”
Higher and higher
The release notes that to that end, USC Sea Grant recently ran workshops in San Diego and Los Angeles and will organize others in Santa Barbara and Orange County.
“This is all about resilience,” Grifman said. “It’s about how communities can prepare so they don’t suffer huge losses, and the time to do that preparation is now, not when they start seeing losses.”
Grifman said the problems that might be caused by rising sea levels would most likely be the result of storm events that occur during high tides. As an example, she pointed to the enormous waves that hit the Southern California coastline in August as a consequence of a hurricane far offshore. Hurricane Marie was hundreds of miles offshore and produced 10-to 20-foot waves along the coast and on Catalina Island. (At its peak, Hurricane Marie was a Category 5 hurricane, the same level as Hurricane Katrina in 2005, but unlike Katrina, Marie never made landfall.)
“That was a storm-based event coupled with high tides, and we saw enormous waves across Southern California,” Grifman said. “That’s the kind of thing we think of as a harbinger, an example of what our future is going to look like.”
