POCKET BEACH. A beach, usually small, in a coastal reentrant or between two 

 littoral barriers. 



POINT. The extreme end of a cape; the outer end of any land area protruding 

 into the water, usually less prominent than a cape. 



PORT. A place where vessels may discharge or receive cargo; it may be the 



entire harbor including its approaches and anchorages, or only the 



commercial part of a harbor where the quays, wharves, facilities for 

 transfer of cargo, docks, and repair shops are situated. 



POTENTIAL ENERGY OF WAVES. In a progressive oscillatory wave, the energy 

 resulting from the elevation or depression of the water surface from the 

 undisturbed level. 



PRISM. See TIDAL PRISM. 



PROBABLE MAXIMUM WATER LEVEL. A hypothetical water level (exclusive of wave 

 runup from normal wind-generated waves) that might result from the most 

 severe combination of hydrometeorological, geoseismic, and other geo- 

 physical factors and that is considered reasonably possible in the region 

 involved, with each of these factors considered as affecting the locality 

 in a maximum manner. 



This level represents the physical response of a body of water to maximum 

 applied phenomena such as hurricanes, moving squall lines, other cyclonic 

 meteorological events, tsunamis, and astronomical tide combined with 

 maximum probable ambient hydrological conditions such as wave setup, 

 rainfall, runoff, and river flow. It is a water level with virtually no 

 risk of being exceeded. 



PROFILE, BEACH. The intersection of the ground surface with a vertical plane; 

 may extend from the top of the dune line to the seaward limit of sand 

 movement. (See Figure A-1.) 



PROGRESSION (of a beach). See ADVANCE. 



PROGRESSIVE WAVE. A wave that moves relative to a fixed coordinate system in 

 a fluid. The direction in which it moves is termed the direction of wave 

 propagation. 



PROMONTORY. A high point of land projecting into a body of water; a HEADLAND. 



PROPAGATION OF WAVES. The transmission of waves through water. 



PROTOTYPE. In laboratory usage, the full-scale structure, concept, or 

 phenomenon used as a basis for constructing a scale model or copy. 



QUARRYSTONE. Any stone processed from a quarry. 



QUAY (Pronounced KEY). A stretch of paved bank, or a solid artificial landing 

 place parallel to the navigable waterway, for use in loading and unloading 

 vessels. 



A-26 



