Mean Low Water Springs (MLWS) (MLWS)

The average height of the two successive low waters during spring-tide periods at a stated location and over a defined observation period.

MLWS is a tidal datum associated with larger astronomical tidal ranges and is calculated by the method adopted by the responsible hydrographic authority. It is an average and should not be confused with Lowest Astronomical Tide or the lowest observed water level. Its value is specific to place, datum and observation period. Atmospheric pressure, wind, river flow and other effects can make an individual low water higher or lower than MLWS.