Sand dunes and native plants on beaches can create a natural buffer against the impacts of sea level rise when they’re allowed to thrive.
UC Santa Barbara researcher Karina Johnston said it’s possible to grow sand dunes in California faster than the rate of sea level rise.
“The amount of sand accumulation over time and the rate at which it was happening, is faster than the rate of sea level rise,” she said.
That’s what she found after a six-year study. But, she also knows that for decades locals and tourists have enjoyed the flat, manicured beaches found up and down the coast.
“A process called grooming or mechanical raking of the beach using heavy equipment became a common practice in the 70s and 80s,” she said.
Johnston said that’s not the best approach for climate resilience. Mechanical raking flattens the beach and disrupts how waves and wind move the sand. When raking stops, plants and dunes re-form to create a natural buffer against sea level rise.
“One of the major concerns for coastal communities is the potential for sea level rise in subsequent years and for coastal flooding to become more prevalent,” Johnston said.
She spent six years monitoring three acres of beach in Santa Monica. The city agreed to stop raking for her study.
“In December of 2016, we hand-distributed four native plant species seeds, and then let it go,” she said.
Her team used drones to document the transformation of the beach over time, and within the study period, Johnston said the area had dunes of up to three feet, as well as much more vegetation.
She said restoration of the sandy ecosystem caused minimal disruption to beach-goers, and it’s a low-cost, nature-based solution for coastal communities, including here on the Central Coast. Johnston published her results in the journal Frontiers in Marine Science.
