Stinson Beach to devise sea-level rise defense plan - Marin Independent Journal

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Stinson Beach will launch a multi-year effort to craft its first sea-level rise defense plan as oceans threaten to swallow up beaches, roads and waterfront homes by the end of the century.

The community is the most immediately vulnerable to sea-level rise on Marin’s ocean coast and could face a water level as much as 10 feet higher by 2100 in a worst-case scenario, according to county officials and state projections. In 2018, the county outlined strategies Stinson Beach could adopt, including elevating roads and homes, building sea walls and dunes, boardwalking entire neighborhoods and building a new sewage system.

“But the nitty-gritty of how to actually do those adaptation strategies, what the benefits and costs are, how you really choose between them and when you do them wasn’t clear out of that report,” said Heather Dennis, a county planner. “So that’s really what we’re seeking to do.”

In the next three and a half years, a community-led group will work with the county and a consultant to plan out when and how to adapt Stinson Beach to these impacts. The group will be similar to that of the county’s Coastal Communities Working Group, but will be made up mostly of Stinson Beach representatives as opposed to representatives from other coastal towns.

“We’re going to try and make this project really driven by the community and run by the community,” Dennis said.

The end result of these efforts, Dennis said, would be a plan in June 2024 listing projects and a suite of funding options. It is intended to be the first of seven such plans tailored specifically to the threats of coastal communities. The others are Dillon Beach, Muir Beach, the eastern shore of Tomales Bay, Inverness, Marshall and Point Reyes Station.

While 10 feet of sea-level rise by 2100 is a worst-case projection for Stinson Beach, the state is calling on coastal areas to be prepared for 3.5 feet of sea-level rise by 2050. County models show much of the existing beach would be lost at that amount. Homes and streets on the northern end of the community could experience regular flooding at just 1 foot of sea-level rise in combination with annual storms. The extent of flooded areas expands significantly at higher levels of sea-level rise.

If left unaddressed in the coming decades, sea-level rise would convert the scenic coastal destination into an unpalatable urban wetland, according to findings in the county’s 2018 assessment. More than 770 homes, six businesses and the vital access roads of Calle del Arroyo and Shoreline Highway would be flooded, in some cases permanently. Septic systems and water pipes would regularly fail. A fire station and the town’s public utility district buildings would be inundated. All told, the damages could reach as much as $1.5 billion in market value, according to the county’s 2018 assessment.

Jesse Peri, assistant chief at the Stinson Beach Fire Protection District, said regular flooding could cut off evacuation routes for communities such as Seadrift in the near term. Calle del Arroyo already floods during high tides.

“I don’t think we necessarily have all of the answers right now, but we’re excited to have a set at the table and develop our priority list,” Peri said.

The district’s secondary fire station, which is projected to be flooded in the coming decades, is mostly used to store apparatus.

“The irony is our water rescue equipment is there,” Peri said with a laugh.

The Stinson Beach planning effort is set to begin in May with a survey sent to communities far outside the village. The survey is meant to provide a greater understanding of how visitors use Stinson Beach, especially in communities where climate change is expected to lead to extreme heat that would prompt residents to escape to cooler coastal areas.

“As this project moves forward, we support maximum public participation,” said Ashley Eagle-Gibbs, conservation director of the West Marin Environmental Action Coalition. “This beach is not only used locally but by others in neighboring communities to seek respite and recreation.”

The multi-year plan is expected to cost $678,000, with funding from the Marin County Community Development Department, the Federal Emergency Management Agency and the California Ocean Protection Council.

The Link Lonk


March 08, 2021 at 07:28AM
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Stinson Beach to devise sea-level rise defense plan - Marin Independent Journal

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