State Parks to reinforce storm-resistant dunes
Partial beach closure happening Tuesday through Friday
A pair of dunes will be on full display this week in Aptos.
But don't get too excited science fiction fans, the happening doesn't include Timothée Chalamet riding a sand worm to Santa Cruz.
California State Parks, in collaboration with its local operating partner, Friends of Santa Cruz State Parks, will close a small portion of Rio Del Mar State Beach near the esplanade Tuesday through Friday to engage in a dune restoration project it hopes will reduce sand erosion, improve coastal resiliency and restore habitat that has been washed away by recent brutalizing winter storms.
Scott Rohlf, staff park and recreation specialist with State Parks' Santa Cruz District, called the effort a “nature-based solution” with lots of upside in the context of rising sea levels and heavy storms intensified by climate change.
“It's something of a pilot project and a test case for what we can do in our region,” Rohlf, who has a master's degree in geology from UC Santa Cruz, told the Sentinel. “Not only can we try to restore some biodiversity … but also we can protect public access and facilities by creating these sorts of flexible coastal resilient features.”
This particular feature involves restoration of historic dunes using sand from the beach itself and debris that has accumulated from recent storms. Rohlf said crews will interlock and stack piles of driftwood logs previously washed up on the shoreline and use them as a stable core to reinforce a pair of sand dunes toward the back of the beach, away from the average tideline.
In addition to providing a clean canvas to later reestablish native coastal plant species, Rohlf said the dunes, which vary in width from 40 to 100 feet and stand at about 5 feet tall, buffer public infrastructure against atmospheric river storms that often bring high surf, storm surges and a swollen Aptos Creek.
The pilot — done in consultation with local experts and the California Coastal Commission — originally launched after high-impact storms struck in 2021, which unlocked emergency operation funding and enough natural material to establish only one of the engineered dunes.
The endeavor, documented by the Sentinel in early 2022, involved coastal geologists with Integral Consulting directing bulldozer operators as they excavated the area and dropped 3,000-pound logs atop one another before covering them up with 2,500 cubic yards of sand from the beach — enough to fill 12 railcars to the brim.
Then, when the historic atmospheric river storms of 2022 and early 2023 struck, Rohlf added, not only did the dune survive the extreme winter and create momentum toward a proof of concept, it provided enough wood material to establish a second dune.
This most recent winter has added to the agency's expanding driftwood budget and has allowed it to complete some reinforcement work this week on the existing dunes. The beach will be closed from Aptos Creek to the east edge of the restroom during construction with public access available on the beach's eastern edge, according to a State Parks release.
“We saw this project as a potential win-win in that we can restore this dune habitat that we have evidence for all the way back to the 1920s pre-development of Rio Flats, as well as provide some of that coastal resiliency,” said Rohlf, referring to historical research and analysis by local experts that helped inspire the project. “That's the whole rationale, I would say, behind the project is: really use as much as what's onsite as possible because that's what nature would have to use to build the dune system. We're just trying to kind of speed up the process a little.”
Despite this week's rearmoring efforts, Rohlf said the agency's budget for ongoing improvements to the project is running dry. He said State Parks is in the process of seeking as much as $400,000 in grant funding to pay for five years of structure monitoring, design improvements and the seeding of native plant species whose roots could act as glue that keeps the dune sturdy.
Most of all, Rohlf believes the sandy experiment can act as a model for how communities can create naturally resilient shorelines that are flexible in the face of an uncertain climate future as opposed to infrastructure established with a mindset of, as he put it, “forced stagnancy.”
“In reality, coastlines are highly dynamic geologic environments that are always changing,” said Rohlf. “Being able to create systems and reintroduce these systems that are flexible in regard to those coastal processes is more of the future that is coming.”