As residents of Stinson Beach face the unavoidable reality of sea-level rise, a new report suggests there is no shortage of potentially effective ways to safeguard their community against it.
The latest assessment by the county’s Stinson Beach Adaptation and Resilience Collaboration, or ARC, comes on the heels of a 2023 report by the Marin County Community Development Agency and consultant Environmental Science Associates. The previous study used sea-level-rise projections from 2018 to forecast impacts on the beach, wetlands, homes, roads and other infrastructure if no preventive measures are taken. It found that numerous areas of Stinson Beach would be exposed to flooding, and that many of the town’s septic systems are already under threat of water infiltration and severe damage.
With Stinson Beach facing a slew of hazards stemming from climate change, the new report explores nearly two dozen adaption options, from levees to cobble-gravel berms to elevated structures. Each option is presented in an exhibit that describes factors like engineering feasibility, environmental and social impacts, regulatory feasibility and economic cost. A matrix scores and compares them, with timelines in an accompanying memorandum.
Isaac Pearlman, a senior county planner who is leading the ARC project, said the report is intended to be a resource for the Stinson Beach community. The report also considers ongoing efforts to facilitate coordination and integration among agencies. These projects include a plan by the Greater Farallones Association to establish new marsh and mudflat habitat along the southern shoreline of Bolinas Lagoon, an Easkoot Creek flood study conducted by the National Park Service, and a community wastewater system feasibility study led by the Stinson Beach County Water District.
As the pace of sea-level rise is expected to quicken later this century, rising as much over the next 30 years as it has over the last 100 years, understanding how to properly time the implementation of some of these adaptation measures is crucial. The ARC report uses updated sea-level-rise projections that are slightly lower than 2018 estimates, though Mr. Pearlman stressed that this doesn’t change the scope of the project.
“It just gives us more time, which is sorely needed, to implement some of these responses,” he said.
The ARC project’s next steps consist of laying out several adaptation pathways that combine multiple interventions to address current and future effects of sea-level rise. The team will hold focus groups in the community, talk to regulatory agencies and stakeholders, and develop a draft roadmap that will be subject to public comment. A first online meeting will take place on Monday, June 17, presenting the latest report.
“At the end of the day, what we’ll have is an adaptation road map that includes all the information, resources and tools for the community to start to take action,” said James Jackson, a hydrologist for Environmental Science Associates.
The ARC team hopes to have the entire planning process wrapped up by year’s end.
A virtual webinar to go over the report’s findings is scheduled for Monday, June 17, at 5:30 p.m. The public can register online.