Edge of the Sea 



Beach Nomenclature 



A "beach" has three main zones (top 

 right): 1. the "backshore" is above 

 the swash of normal waves at high 

 spring tides; 2. the "foreshore" is 

 the zone between the high-water and 

 low-water marks; 3. the "offshore" 

 zone extends seaward from the low- 

 water mark to a depth where appreci- 

 able movement of material ceases. 

 Diagrammatic composite sand and 

 shingle beach profiles (middle and 

 lower right) illustrate the various 

 "beach" terms. 



COMPOSITE SAND BEACH PROFILE 



"Wave length" is the distance from 

 wave crest to wave crest. "Wave 

 height," is the vertical distance 

 from trough to crest, The particles 

 of water in a wave do not move 

 forward with the wave, but have 

 an open circular motion. The radii 

 of these paths decrease with depth. 



COMPOSITE SHINGLE BEACH PROFILE 



BEACH RIDGES 



Above: A "rip current" is a strong 

 narrow current moving away 

 from the beach. It flows through 

 the breakers and fans out beyond. 

 These wave-induced currents seem to 

 be associated with depressions 

 or troughs in the beach. 



Right: Weather chart for the North 

 Atlantic shows conditions which are 

 fairly typical in the winter months. 

 Storm waves formed off the coast of 

 Newfoundland began to break on the 

 English coast midday, March 14. 



264 



