high seas—The open sea beyond and adjacent to a country’s territorial waters, which is subject to the exclusive jurisdiction of no one nation. Littoral nations frequently exercise limited jurisdiction over portions of the high seas adjacent to their coasts for purposes of enforcing customs and other regulations.

high water—The maximum height reached by a rising tide. This may be due solely to the periodic tidal forces or due to the effects of prevailing meteorological conditions superimposed on them.

high water line— ¹ A line defined by the boundary of a body of water at it’s normal high water level. ² The place on the bank or shore up to which the presence and action of water are so usual and long continued as to impress on the bed of the stream a character distinct from that of the banks with respect to vegetation and the nature of the soil. ³ In tidal water, the high-water line is the intersection of the plane of the mean high water with the shore.

high water mark—See high water line.

higher high water (HHW)—The higher of the two high waters occurring during a tidal day where the tide exhibits mixed characteristics.

higher low water (HLW) —The higher of two low waters of a tidal day where the tide exhibits mixed characteristics.

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Source: NSPS “Definitions of Surveying and Related Terms“, used with permission.

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