How is mean high water defined?

Mean high water is defined as the average height of all high waters observed over a specific time period, typically calculated over 19 years to account for variations in tide caused by astronomical factors. This measurement is utilized in various maritime activities and regulations, as it provides a consistent reference point for navigation, flood control, and coastal land use planning.

The reason this definition is important is that it offers a reliable benchmark that reflects the typical conditions of high water, rather than just a single event or peak measurement, which can vary widely. By averaging the high water marks over an extended time frame, Mean High Water becomes a standard point of reference that aids in marine navigation and shoreline management.