A foundational assumption of private property law is that land is static enough to be mapped, gridded, and divided. The trouble with this assumption is that the space where the ocean meets the sand is ambulant — ambulant always and by definition, although as climate change accelerates, the degree of ambulation increases at pace.
The method sanctioned by the U.S. Supreme Court for calculating the boundary between public coast and private land is practically useless in the State of California today. A 1935 court case, Borax Consolidated Ltd. v. City of Los Angeles, determined that the boundary is set by the mean high tide line, calculated over a period of 18.6 years. The number 18.6 was determined by the court to be the length of time in which there might be a measurable change in sea level. The ruling offers the illusion of precision. Over a period of 103 months and six days, simply measure where the mean high tide intersects the beach (a calculation that combines the horizontal reach of the tide with the vertical depth of the tide), draw the average, and there it is. But for a variety of reasons, that’s not what happens in practice.
The most obvious stumbling block is that water levels are rising much faster today than in 1935. An average mean high tide calculated over 18.6 years is not a reliable indication of water movement in the future, or of the associated accretion or erosion of the coast. Second, demarcating a boundary via years of surveyor calculation is expensive and time-consuming. The required research entails not just tide calculations, but complicated historical analysis to determine what changes to the shoreline are “natural” as opposed to caused by humans. The agency that would make these calculations, California’s State Lands Commission, is thin on staff and resources, such that they generally only make an official declaration of the mean high tide line when it is required for settling a legal dispute. Underfunding has left the agency reactive rather than proactive, leaving large stretches of the coast open to practical uncertainty.
Third, public space in many cases extends beyond the mean high tide line. In Malibu, and many other parts of California, beachfront homeowners use an expanded public beach as a bargaining chip when seeking home improvements. That is, they set up a lateral easement for the dry sand in front of their property in exchange for permission to make improvements on their home — a new deck or an extra bedroom — which would otherwise not be permitted. From above, Escondido Beach’s property lines look like a set of crooked teeth, with random strips of private land smashed between public space. Were you to walk along the beach, keeping a perfectly consistent distance from the water, you would pass through swaths of private land and swaths of public land. As the Los Angeles Times put it, “it’s impossible to tell which houses have these easements, and which do not, without carrying a sheaf of maps and property records.”