The Dunes Are Alive Along The Santa Monica Coast
We covered a lot of ground during our recent special series on climate change, including the grim fate of our beaches. As our science reporter Jacob Margolis put it: based on the latest research, the beaches from Santa Monica to Malibu could be unrecognizable by the end of the century.
One of the ways the city of Santa Monica has been working to address specific aspects of that change — sea-level rise and coastal flooding — is with something called "living dunes."
Part naturally occurring sandhills, part landscaping, the living dunes represent an attempt to help nature restore itself along the Santa Monica waterfront.
The Bay Foundation, a non-profit environmental group, partnered with the city to set aside three acres of sand for this beachside experiment to see how well the dunes could combat beach erosion compared to other methods.
The program was set up three years ago near the Annenberg Community Beach House on a stretch of beach that has been groomed and leveled for more than 50 years. Typically along the coast, trucks and tractors are brought in to rake the beach of trash and debris, but this disrupts the way beaches are supposed to look.
"Beaches normally want to have plants and dunes," said researcher Melodie Grubbs, director of watershed programs at The Bay Foundation. Coastal cities have created an image of big, pristine white beaches that attract beachgoers, but that aesthetic has come at the cost of habitat and protection from coastal flooding.
Grubbs said it's time for action.
"As a coastal community, we need to start doing things now," she said. "This is a matter of: Do we want to keep our beaches and enjoy them for future generations? And this is definitely a part of the solution."
THE GREENER OPTION
State agencies and city planners have tried several methods when trying to shore up the beaches and prepare for rising sea levels.
Traditionally, seawalls and other types of flooding protection have been the default. The priorities in the past have been to save homes and infrastructure first. But these can be expensive and also come "at the cost of the beach," Grubbs said.
When hard structures are in place, the tide pulls sand off beaches, making erosion worse and creating a cliffside with no beach below.
The advantage of living dunes is that in addition to protecting the coastline, they are considered a greener option because they use existing sand instead of re-located sand — which is costly and creates more pollution by trucking it in.
Santa Monica's not the only city to experiment with living dunes. Encinitas is using a similar method on Cardiff State Beach. But where the beaches on Cardiff have rocks supporting the dunes, Santa Monica is using plants and fencing to help maintain shape.
At the onset of the experiment, researchers blanketed the test area with 40,000 seeds with the idea that coastal beach plant species would reset the ecosystem. The native, drought-resistant plants could create a root system to sustain the structure of the dunes naturally. It's an experiment, so "we sort of just put it here and wait and see what would happen. We just left it," said Grubbs.
Since installation, areas on the site have risen above 1-3 meters in height. The beach is dotted with beautiful flowering sand verbena and beach evening primrose throughout. Yellow and purple blooms create a beach with colorful freckles that harken to the shorelines of the East Coast. Also thriving are sea scale and beach bur, both low-lying plants that help support the miniature sand dunes.
THE LIVING LAB
Researchers will continue to evaluate how the dunes might act as protection for coastal infrastructure. This demonstration site will provide not only a scientific basis to develop guidelines and protocols but an integrated, locally based program for increasing the usefulness of natural environments in a developed area.
The foundation is publishing its findings from "soft" low-cost natural shore protection from sea-level rise and storms in the next year.
"This project gave us a real opportunity to see what this type of soft-scape project could do for the ecosystem," said Grubbs. "It's a living lab for us to watch."
The dunes, also known as dune hummocks, are also restoring habitat for invertebrates, birds, and rare coastal vegetation species.
Groomed beaches provide a harsh landscape for shorebirds and insects, offering them little protection from natural predators. Greenery serves as both cover and a food source for smaller organisms. Larger species like birds are able to nest and find shelter within the dune hummocks. The Western Snowy Plover, a federally recognized threatened species, has even been spotted on the beach after an absence of over 70 years, due to the restoration pilot.
The project has also proven to be something of a "cultural experiment," Grubbs said. "Generations of people in this area have not seen this kind of beach. But it also acts as a model. This shows that regular beach use and restoration projects can exist in the same space," she said.
Next up for The Bay Foundation's beach restoration efforts is the "Malibu Living Shoreline Project."
For this one, they'll partner with the Los Angeles County Department of Beaches and Harbors and the California State Coastal Conservancy to restore 3 acres of sandy beach and dune habitat at Zuma Beach and Point Dume Beach.