TIDAL INLET. (1) A natural inlet maintained by tidal flow. (2) Loosely, any 

 inlet in which the tide ebbs and flows. Also TIDAL OUTLET. 



TIDAL PERIOD. The interval of time between two consecutive, like phases of 

 the tide. (See Figure A- 10.) 



TIDAL POOL. A pool of water remaining on a beach or reef after recession of 

 the tide. 



TIDAL PRISM. The total amount of water that flows into a harbor or estuary or 

 out again with movement of the tide, excluding any freshwater flow. 



TIDAL RANGE. The difference in height between consecutive high and low (or 

 higher high and lower low) waters. (See Figure A- 10.) 



TIDAL RISE. The height of tide as referred to the datum of a chart. (See 

 Figure A- 10.) 



TIDAL WAVE. (1) The wave motion of the tides. (2) In popular usage, any 

 unusually high and destructive water level along a shore. It usually 

 refers to STORM SURGE or TSUNAMI. 



TIDE. The periodic rising and falling of the water that results from 

 gravitational attraction of the Moon and Sun and other astronomical bodies 

 acting upon the rotating Earth. Although the accompanying horizontal 

 movement of the water resulting from the same cause is also sometimes 

 called the tide, it is preferable to designate the latter as TIDAL 

 CURRENT, reserving the name TIDE for the vertical movement. 



TIDE, DAILY RETARDATION OF. The amount of time by which corresponding tides 

 grow later day by day (about 50 minutes). Also LAGGING. 



TIDE, DIURNAL. A tide with one high water and one low water in a day. (See 

 Figure A- 10.) 



TIDE, EBB. See EBB TIDE. 



TIDE, FLOOD. See FLOOD TIDE. 



TIDE, MIXED. See MIXED TIDE. 



TIDE, NEAP. See NEAP TIDE. 



TIDE, SEMIDIURNAL. See SEMIDIURNAL TIDE. 



TIDE, SLACK. See SLACK TIDE. 



TIDE, SPRING. See SPRING TIDE. 



TIDE STATION. A place at which tide observations are being taken. It is 

 called a prirmvy tide station when continuous observations are to be taken 

 over a number of years to obtain basic tidal data for the locality. A 

 secondary tide station is one operated over a short period of time to 

 obtain data for a specific purpose. 



A- 36 



