Tidal Definitions for Land Surveyors

tidal—Of or pertaining to tides.

tidal bench mark—See bench mark, tidal.

tidal bore—A phenomenon observed on certain tidal estuaries where the incoming tide advances upstream as an abruptly rising standing wave; an eagre.

tidal current—The alternating horizontal movement of water associated with the rise and fall of the tide caused by astronomical tide-producing forces.

tidal cycle—A complete set of tidal conditions, as those occurring during tidal day, lunar month, or a Metonic cycle.

tidal datum—See datum, tidal; datum, Sea Level, 1929; datum, National Geodetic Vertical, 1929 (NGVD 29).

tide-1 The periodic rising and falling of water that results from the gravitational attraction of the moon and sun acting upon the rotating Earth. Should not be used to designate the horizontal movement of water, i.e., tidal current. 2 A flood in a stream (colloquial, southeast United States).

tide, ebb—A term indiscriminately used for falling tide or seaward current. Technically, ebb refers to current.

tide, flood—A term indiscriminately used for rising tide or landward current. Technically, flood refers to current. Should only be applied to the horizontal movement of water (current); applying the terms “flood” or “ebb” to the vertical movement of water (tide) is discouraged as it leads to uncertainty.

tide, neap—High water which is lower than usual; usually when the moon is in the first and third quarters and the tidal forces of the sun and moon are opposed.

tide, spring—High water—higher than usual—at full moon and new moon resulting from the tidal forces of the sun and moon acting in the same direction.

tide, storm—Abnormally high or low water in bays and rivers caused by winds and fresh water runoff.

tide level-1 The height of the tide halfway between the heights of mean high water and mean low water; ordinary tide level. 2 The height of the tide above a specified level. 3 The tide when it is at a specified level.

tide records-1 Annual tide tables, current tables, and specific reports of the U.S. Coast & Geodetic Survey (now the National Geodetic Survey). 2 Information also obtainable from the records of nearest tide gages of the National Ocean Service; records of the Beach Erosion Board; records from the nearest station of the U.S. Coast Guard; records from the nearest station of the National Weather Service; records in local offices of the U.S. Army Corps of Engineers; and local reports, records, and statements of individuals.

 tide station—See station, tide.

tide tables— Tables giving daily predictions of the times and heights of the tide.

tidelands—All coastal areas that are situated above mean low tide and below mean high tide, particularly if such areas are alternately uncovered and covered by the ebb and flow of the ordinary daily tides.

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

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