Stinson Beach neighbors have asked the California Coastal Commission to block a home proposed for the last remaining shorefront lot in Stinson Beach—an area impacted by floods and sea-level rise. Marin supervisors approved the project on Nov. 7 after the Planning Commission required the property owners to reduce the size of the home from 1,500 square feet to 1,300 square feet, eliminate a planned garage and restore a portion of a sand dune on the lot. But opponents of the proposal argue that the plan violates the California Coastal Act and Marin’s coastal development regulations, which prohibit building in environmentally sensitive habitat areas. They argue that it makes no sense to build in a flood zone where storms are expected to become more frequent and powerful. The home would be built in the Calles, where last winter’s storm flooded the neighborhood, inundated septic systems and damaged several homes. County officials acknowledge that the construction would violate Marin’s coastal development regulations but say they had to approve it anyway to avoid a taking of private property. The property is owned by Lake Tahoe resident Brian Johnson and several relatives, who have spent $350,000 on permits and environmental assessments so far. They say their proposed home has been appraised at $3.5 million. Mr. Johnson’s grandparents owned a 540-square-foot cottage at the site on the lot, located at 21 Calle Del Onda, but it burned down in 1983. The United States Constitution requires governments to compensate property owners when their regulations prevent them from realizing the economic value of their land. In such cases, the county conducts an analysis to determine the minimum amount of development required to avoid depriving a property owner of realizing their reasonable economic expectations. The appeal to the California Coastal Commission was filed on Nov. 30 by Elizabeth Brekhus, an attorney for Stephen Sarafian and Marisa Atamian-Sarafian, who own a home next door. The neighbors maintain that building a smaller house—one roughly the same size as the property destroyed by fire—would be sufficient to meet the Johnsons’ reasonable expectations of developing their property. Their appeal states that several homes of roughly 500 square feet in the neighborhood have sold for over $1 million.