Cal. PRC § 6339

(a) Boundaries established by boundary agreements entered into and recorded pursuant to Section 6336, as to all parties thereto, shall be fixed and permanent without change by reason of fluctuation due to the forces of nature, except that any lands that may thereafter be submerged or become subject to the ebb and flow of the tide, shall, so long as such conditions exist, be subject to the easement in favor of the public for commerce, navigation, and fisheries.

(b) Boundaries mapped and described pursuant to this article, other than boundaries established by parties to a boundary agreement entered into pursuant to Section 6336, shall not be binding upon any upland owner or other party affected thereby, whose rights, if any, shall not be affected by any provision of this article. If any such rights have been previously determined pursuant to law, they shall remain unaffected by the provisions of, and proceedings undertaken pursuant to, this article. If any such rights have not been previously determined, they may be determined pursuant to any law existing as of January 1, 1976, or that may be thereafter enacted. However, any such upland owner or other person affected by the master map and description may consent in writing to bind his land or any claimed title or interest therein to the boundaries so mapped and described. Such consent shall be acknowledged by the party executing it and shall be recorded in the office of the county recorder of the county in which the land affected thereby is located. The consent shall thereafter have the same effect as if a boundary agreement had been entered into pursuant to Section 6336, and the provisions of subdivision (a) of this section shall be applicable thereto.