San Francisco Chronicle - (Sunday)
Fragile existence for homes by sea
With vast damage feared from rising water by 2030, Stinson Beach considers dunes as temporary shield
Steps from the white sands of Stinson Beach, Gary Bisson went from one house to the next on a blustery blue-sky December day, setting out the garbage and recycling bins at vacation properties. A selfdescribed survivor of the Summer of Love, Bisson found refuge here 50 years ago and never left.
At times during those decades, the ocean had all but devoured the beach during big El Niño storms. Bisson recalls in 1982 watching seals bob along Calle del Arroyo, the only egress for oceanfront neighborhoods, when a 100year storm swept about a halfdozen beachfront homes into the sea and flooded the streets.
That storm decades ago illustrates what sea level rise could do to this coastal community, one of the most vulnerable on the Marin County coast. A 2016 assessment of the county’s shoreline towns found that without interven
tion, flooding linked to rising seas could damage or destroy 200 to 400 of Stinson Beach’s 775 homes by 2030.
The solutions are imperfect. Some communities are preparing to move infrastructure, homes and any new development away from coastal lowlands. Others are building seawalls and different types of structural armor.
Marin County officials are considering a temporary, more ecologically oriented solution: build dunes to absorb some of the pressure from king tides and big storms heightened by rising seas.
Dunes are nature’s storm absorbers, with tall sand mounds and deep-rooted grasses that can soak up some of the deluge.
Supervisor Dennis Rodoni, whose district encompasses most of the county’s coast, said he believes the cost and effort are worth it, even for a system that might work for only several decades.
“That’s what we’re trying to learn from the studies — to see how well (dunes) might work to delay the inevitable,” Rodoni said.
It is an existential threat for Stinson Beach, a white-sand crescent beach beloved despite frigid waters and fog, the end of the 116-year-old Dipsea race where Mount Tamalpais’ western flank tumbles into the sea. Its population of about 600 swells to more than 10,000 on summer weekends.
The sands of Stinson Beach could disappear as soon as 2050. By the end of the century, nearly 600 homes with a collective market value of $1.5 billion could be damaged beyond repair.
Encroaching seas threaten to put $8 billion to $10 billion worth of California properties underwater by 2050, according to a 2020 report from the Legislative Analyst’s Office. In Marin County, more than a quarter of properties are at risk.
Across coastal California, dunes, long trampled by human development along the water, are increasingly under discussion as a potential tool to stave off the effects of damaged ecosystems and climate change.
The county released a feasibility study last fall for dunes that found that these structures could offer real protection for the community from the impacts of 1½ feet of sea level rise by 2045 and 3½ feet by 2068, scenarios recommended by the state’s latest guidance. The cost was estimated at $48 million to $55 million, compared with an estimated $155 million for more permanent structures such as seawalls, according to the study.
One consideration in the study is whether to include cobble-gravel berms, artificial embankments under some areas of beach leading up to the dunes, which could lessen erosion but, if wind sweeps the sand away, make it uncomfortable for barefoot beachgoers.
A key challenge will be securing enough sand to build the dunes and maintain them.
James Jackson, a civil and coastal engineer with Environmental Science Associates, the San Francisco firm hired to conduct the study, said the most likely scenario involves getting sediment dredged from San Francisco Bay, a plan that will require complex approvals from state and federal agencies, including the Greater Farallones National Marine Sanctuary.
“Sand is a hot commodity,” Jackson said.
Stinson Beach has always been a seasonal post ruled by the whims of the ocean. Dan and Teri Fruchtman bought a beachfront home in 1987, five years after that infamous storm most locals bring up during conversations about rising seas. Dan Fruchtman said he takes it as a good sign that his A-frame home right on the beach has survived. It’s built on infill and protected by a modest dune he and his immediate neighbors are trying to repair, removing old buried railroad ties, trucking in soil and sand, and planting native dune grasses.
Fruchtman, who retired from a career running a security firm, said he is trying to do what he can while accepting that nothing lasts forever.
Stinson Beach is part of the National Park Service’s Golden Gate National Recreation Area, which manages the southern end of the beach, the most protected and broad section of sand, said Kristen Ward, an ecologist with the recreation area’s division of natural resource management and science.
The park service is collaborating with the county to find ways to protect the community. Ward said dunes are an ideal solution because of the potential ecological benefits.
The park service began taking twice-yearly measurements of the beach several years ago to start tracking both seasonal changes and beach loss over time. It has not yet collected enough data to draw any conclusions, but similar measurements collected for decades at Ocean Beach shows how its southern shoreline is quickly eroding.
The U.S. Army Corps of Engineers embarked on a $7 million project completed last fall to develop a 3,000-footlong, 30-foot-tall berm to fortify the beach.
The public meetings, reports and discussions over Stinson Beach’s tenuous future are increasingly dominating talk in the community. Bisson said he had just assumed his children, grandchildren and future generations could inherit this place, but now realizes that may not be true.
“The Arctic is melting. It’s only logical,” said Bisson, 74. “The Earth is so fragile. It’s a shame what we’ve done to it.”
His son, Toby Bisson, said the discussions can feel dystopian, especially when it seems officials from outside the area are suggesting that coastal residents abandon their homes. He is a supervisor with the water district, assistant fire chief and president of the community center, and serves on a community board on flooding. He said he believes other communities will be watching how they handle this issue and wants to be a model of resilience.
“We’re definitely in the bull’s-eye, and people are looking at what we’re doing here,” Toby Bisson, 53, said.
But he knows the ocean too well to believe any defenses will last forever. He’s built countless castles in those sands as a child and later with his own children. When the tide comes in, you build a wall to defend it, then a moat to let the waters circumnavigate its walls. Then a wave comes and washes everything away.
“We should be allowed to protect ourselves,” Toby Bisson said. “But ultimately the ocean will win.”
“That’s what we’re trying to learn from the studies — to see how well (dunes) might work to delay the inevitable.”
Supervisor Dennis Rodoni, whose Marin County district encompasses most of the county’s coast