MHW
Mean High Water (MHW) is the average of all the high water heights observed over a period of several years. For example, in the United States this period spans 19 years and is referred to as the National Tidal Datum Epoch.
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Wikipedia
Mean High Water (MHW) is the average of all the high water heights observed over a period of several years. For example, in the United States this period spans 19 years and is referred to as the National Tidal Datum Epoch.