Question:
If a stream with a state highway marker goes under the Pacific Coast Highway and into a beached cove, can I walk down the center of the stream to the ocean and go for a swim? The land surrounding the stream is private, and the landowners would like to assert that no access to the cove is allowed, even from a boat. (Mike Pinkerton)

Answer:
In California, land is deeded under flowing stream channels, so you would be trespassing. If the land is posted with no trespassing signs at 1/3 mile intervals, fenced or under cultivation you could be cited for this violation (Penal Code, Section 602.8). The water you described is state water and as long as you were floating on the water, such as in a boat, there would be no violation.