Mean low water refers to the average lowest level of water recorded during low tide over a specific period of time, typically within a 19-year cycle known as the Metonic cycle. It is an important measurement used in marine navigation and coastal engineering.
Mean low water is determined by analyzing a series of low tide data spanning several years, usually collected at a specific location. The measurements are recorded at regular intervals, and the lowest level of water obtained during each low tide is noted. These values are then averaged out to derive the mean low water level.
This measurement serves as a reference point for various purposes, including determining safe navigation depths for ships, assessing the depth of water in harbors and coastal areas, and constructing and maintaining structures along the coastline. It provides valuable information for coastal engineers, hydrographers, and marine surveyors.
Mean low water is often related to other tidal measurements, such as mean high water, mean high water springs, and mean high water neaps, to establish tidal ranges and create tide tables used by mariners to plan their activities and avoid hazards.
Understanding mean low water is essential for safe and efficient navigation, as it helps in identifying navigable water depths and areas that may be hazardous during low tide periods. It provides a standardized benchmark for assessing water levels, allowing travelers and engineers to make informed decisions when operating in coastal environments.
