EM 1110-2-1100 (Part II)
30 Apr 02
Areal extent of tidal types (Harris 1981)
Glossary of tide elevation terms.
(1) The differences in tidal envelopes have given rise to certain terminologies regarding the high and
low crests of the tide. The following list of terms, reprinted from the "Glossary of Terms" of the Shore
Protection Manual (1984), describes specific aspects of typical tidal records. Each term is referenced to
(2) DATUM. A base elevation from which vertical heights or depths are referenced. The reference
elevation is locally defined; therefore, a list of commonly used datums is presented in Part II-5-4.
(3) DIURNAL TIDE. A tide with one high water and one low water in a tidal day.
(4) EBB CURRENT. The tidal current away from shore or down a tidal stream; usually associated with
the decrease in height of a tide, associated with a falling tide.
(5) EBB TIDE. The period of tide between high water and the succeeding low water: a falling tide.
(6) FLOOD CURRENT. The tidal current toward shore or up a tidal stream, usually associated with
the increase in height of the tide associated with a rising tide.
(7) FLOOD TIDE. The period of tide between low water and the succeeding high water; a rising tide.
Water Levels and Long Waves