Variability of Tidal Datums and Accuracy in Determining Datums from Short Series of Observations.

Abstract

Tidal datum planes are used to determine the positions of boundaries, as planes of reference for maps and charts, in the design of coastal structures, and to delineate the extent of land uses in coastal areas. Even small differences in accepted values of datums are significant in low-lying coastal areas. The temporal and spatial variability of tidal datums, the length of record used to determine datums, their rela­tionship to the National Geodetic Vertical Datum of 1929, and two methods of deter­mining tidal datums from short series of observations are presented. Statistical analyses of accuracies of datum planes based on short periods of record are given for the United States' East, Gulf, and West Coasts.