Some homeowners in the lower-lying areas of Stinson Beach could be the target of what the California Coastal Commission refers to as "managed retreat," which means they're in a zone where they will either need to move or abandon their homes as sea levels rise.

There's currently a battle of compromise going on between Marin County planners and the Coastal Commission over what to do about some parts of Stinson Beach. As KPIX reported on Earth Day, residents in two neighborhoods of the town on Highway 1 received notices from the county six years ago telling them that rising sea levels would potentially have an impact on their ability to get permits for improvements on their properties.

"That equates to 'can’t sell your house,' and that equates to loss of the value of it so there was an extreme reaction," says area resident Mike Matthews, who's president of the Stinson Beach homeowners' association.

Advance planners at the Marin County planning department like Jack Liebster are now running up against the state's Coastal Commission, which three years ago rejected an "adaptation report" from the county regarding vulnerable coastal zones. That plan included an explainer about managed retreat showing examples of California towns, like Pacifica and Ventura, where eminent domain had been used to purchase property that was too close to the water and rebuild dunes. In addition to Stinson, areas around Bolinas and Inverness are also considered highly vulnerable.

The Coastal Commission is pushing the county to update its Local Coastal Plan and essentially plan to abandon the entire town of Stinson Beach and everything within 1,000 feet of the shoreline in the next 100 years.*

Liebster says that the county is discussing creating a new system of dunes at Stinson Beach with imported sand and sea grass. He says the county is weighing that and other "nature-based alternatives."

Matthews says there's a need to be pragmatic, since acquiring or moving every house isn't feasible. He's pushing to look ahead only 20 years, instead of 100, as he tells KPIX.

"It is true you have to look for the worst-case events in planning but you want to have some sense that they’re actually going to happen," Matthews says. "Let’s see what actually does happen and then manage it."

The Coastal Commission sees rising sees as an inevitability, and all those houses that are just steps from Stinson Beach are likely to be underwater sooner or later.

The two neighborhoods that are seen as most vulnerable are called the Calles and the Sonoma-Patio, and they're pushing for interim solutions like the construction of a seawall — something that the more affluent area called Seadrift did when it was built, installing an expensive rock wall along the ocean.

The 2018 report laid out a series of strategy options that included raising roadways and homes, boardwalking entire neighborhoods, and building seawalls and dune systems. But figuring out the cost-benefit analysis has yet to be done, and it's not at all clear that the Coastal Commission is open to these expensive compromises.

County planner Heather Dennis told the Marin Independent Journal last month that "the nitty-gritty of how to actually do those adaptation strategies" is what will hopefully happen soon, including "how you really choose between them and when you do them."

County models show that some homes in Stinson Beach will flood with just one foot of sea level rise, and the state is pushing the county to plan for 3.5 feet by 2050, or about one foot every ten years. At that point, most of the existing beach would disappear.

The planning process is expected to last three years, and creating the plan is estimated to cost $678,000 — with funding coming from the Marin County Community Development Department, FEMA, and the California Ocean Protection Council.

*Update: The Coastal Commission has responded to KPIX's reporting and is saying that it included inaccuracies. The commission issued the following statement:

The KPIX team never contacted the Coastal Commission about this story on managed retreat in Stinson. We were never asked to respond to any of the comments about the agency in the story, have never spoken to the reporter and did not say “there is no more time for compromise” about working with a community on managing sea level rise. We do not believe and would never say the entire community of Stinson or Highway 1 should be abandoned to the ocean. Reasonable people disagree on how to deal with sea level rise and the question for California is really about what solutions are best for the public, access to beaches and the state’s $40 billion coastal economy that depends on a narrow band of shoreline, while also addressing private development an infrastructure in a way that is equitable and consistent with the law. For every sea wall that’s built, the public can lose a beach. The Coastal Commission is working with communities across California on how to grapple with these very difficult choices that take some time to work out.

Photo: Corina Rainer