EM 1110-2-1100 (Change 1)
31 Jul 03
POINT
(1) The extreme end of a CAPE, or the outer end of any land area protruding into the water, usually less prominent
than a CAPE. (2) A low profile shoreline promontory of more or less triangular shape, the top of which extends seaward.
POORLY-SORTED (POORLY-GRADED)
Said of a clastic sediment or rock that consists of particles of many sizes mixed together in an unsystematic manner
so that no one size class predominates.
PORE PRESSURE
The interstitial pressure of water within a mass of soil or rock.
POROSITY
Percentage of the total volume of a soil sample not occupied by solid particles but by air and water, η = Vv/VT
100.
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. Protection may be provided by natural or artificial features.
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.
The chance that a prescribed event will occur, represented by a number (p) in the range 0 - 1. It can be estimated
empirically from the relative frequency (i.e. the number of times the particular event occurs, divided by the total count of all
events in the class considered).
PROBABILITY DENSITY
Function specifying the distribution of a variable.
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 geophysical 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.
PRODELTA
The part of a DELTA that is below the effective depth of wave erosion, lying beyond the delta front and sloping
down into the basin into which the delta is advancing.
PROFILE, BEACH
The intersection of the ground surface with a vertical plane; typically perpendicular to the local shoreline, and may
extend from the behind the DUNE line or the top of a bluff to well seaward of the breaker zone. (See Figure A-1)
Appendix A Glossary of Coastal Terminology
A-59
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