County funds expanded monitoring after geotechnical report finds Seal Cove landslide advancing

Supervisor Ray Mueller said the county would press ahead with monitoring and preliminary planning after an updated geotechnical study showed the active Seal Cove landslide has expanded and continues to move toward the ocean.

"We're going to be using land monuments and drones to do active surface monitoring," Mueller said at a public briefing; he added he had worked with the county executive to secure "half $1,000,000" in funding to start monitoring and to hire a consultant to study groundwater management.

The consulting team from Cotton Shires and Associates presented the study and described its methods and findings. The lead presenter said long-term surface surveys at a nearby distillery show lateral movement of about "2.7 inches per year," which rose to roughly 3.3 inches per year during the high-precipitation 2023 year. The consultant also said "the landslides recently expanded about 100 feet to the south" and stressed that subsurface data are sparse, limiting confidence in models of deep failure surfaces.

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