Low-tide elevation is a naturally formed area of land which is above water and surrounded by water at low tide but submerged at high tide. It may be a mudflat or reef.
Legal status
Low tide elevations may be used as basepoints for the calculation of maritime zones unless they lie at a distance exceeding the breadth of the territorial sea (12-miles) from the nearest mainland or island,
References
Low-tide elevation Wikipedia(Text) CC BY-SA