t 



Surging - wave peaks up, but bottom rushes forward from under 

 wave, and wave slides up beach face with little or no 

 bubble production. Water surface remains almost plane 

 except where ripples may be produced on the beachface 

 during runback. 



BREAKER DEPTH - The Stillwater depth at the point where a wave breaks. 

 Also BREAKING DEPiH. (See Figure A-2.) 



BREAKWATER - A structure protecting a shore area, harbor, anchorage, 

 or basin from waves . 



BULKHEAD - A structure or partition to retain or prevent sliding of the 

 land. A secondary purpose is to protect the upland against damage 

 from wave action. 



BUOY - A float; especially a floating object moored to the bottom, to 

 mark a channel, anchor, shoal, rock, etc. 



BUOYANCY - The resultant of upward forces, exerted by the water on 

 a submerged or floating body, equal to the weight of the water 

 displaced by this body. 



BYPASSING, SAND - Hydraulic or mechanical movement of sand from the 



accreting updrift side to the eroding downdrift side of an inlet 

 or harbor entrance. The hydraulic movement may include natural 

 as well as movement caused by man. 



CANAL - An artificial watercourse cut through a land area for such uses 

 as navigation and irrigation. 



CANYON - A relatively narrow, deep depression with steep slopes, the 

 bottom of which grades continuously downward. May be underwater 

 (submarine) or on land (subaerial). 



CAPE - A relatively extensive land area jutting seaward from a continent 

 or large island which prominently marks a change in, or interrupts 

 notably, the coastal trend; a prominent feature. (See Figure A-8.) 



CAPILLARY WAVE - A wave whose velocity of propagation is controlled 



primarily by the surface tension of the liquid in which the wave is 

 traveling. Water waves of length less than about 1 inch are con- 

 sidered capillary waves. Waves longer than 1 inch and shorter than 

 2 inches are in an indeterminate zone between CAPILLARY and GRAVITY 

 WAVES. See RIPPLE. 



CAUSEWAY - A raised road, across wet or marshy ground, or across water. 



CAUSTIC - In refraction of waves, the name given to the curve to which 

 adjacent orthogonals of waves refracted by a bottom whose contour 

 lines are curved, are tangents. The occurrence of a caustic always 

 ^^ marks a region of crossed orthogonals and high wave convergence. 



A-5 



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