Mean High Water (MHW) Line

Mean High Water (MHW) line is a tidal datum. It is the arithmetic mean of the high water heights observed over a specific 19-year Metonic cycle (the National Tidal Datum Epoch). Proposed work and structures seaward of the mean high water line are subject to Federal regulatory authorities carried out by the U.S. Army Corps of Engineers and to State and local regulatory authorities as well. In general, most land and water areas seaward of the mean high water line are subject to the Public Trust Doctrine. The mean high water line also marks the seaward boundary of the jurisdiction of a municipality's planning and zoning authorities.

Nearby pages
Mean sea level, Mean wind speed, Measles, Measure of effect measurement endpoint, Measure of exposure, Measurements of land