measurements taken over the National Tidal Datum Epoch (NTDE) period.
NTDE's and keep tidal datum elevations up-to-date to reflect
NOAA provides tidal datums for each of the twelve active tide
The tidal datums provided by NOAA are based on a vertical datum and tide
datum," and all other tidal datums are measured from this point.
Although both site elevation and tidal height are expressed relative to a tidal datum, it is important to distinguish these two terms: site elevation refers to the elevation of the sampling point relative to MHW, whereas tidal height (relative to mean lower low water) refers to the maximum elevation of the surface of the water for a given high tide.
The raw elevation data were transformed to local tidal datums. The NAVD88 vertical datum is a geodetic mean sea level datum and the standard vertical datum used for surveying and engineering in the continental United States.
The average of the Higher High Water height on all tidal days observed during a tidal datum epoch.
The average of the Lower Low Water height of all tidal days during the tidal datum epoch.
The average of the Lower Low Water height on all tidal days observed during a tidal datum epoch.
Tidal datums are commonly misconceived to be fixed planar levels rather than undulating time and space-dependent surfaces.
Oregon coastal salt marsh upper limits and tidal datums
. Estuaries, 4: 198-205.