21 GCA § 9202: Boundaries by Water.

Except where the grant under which the land is held indicates a different intent, the owner of the upland, when it borders on tidewater, takes to ordinary high-water mark; when it borders upon a navigable stream, where there is no tide, the owner takes to the edge of the stream, at low-water mark; when it borders upon any other water, the owner takes to the middle of the stream.