The exposed portion of the beach between the beach face and the landward limit of storm-wave influence.


The seaward return of water following the uprush on the beach face; also, water thrown back by an obstruction, such as a ship, breakwater, or cliff.


An elongate, slightly submerged sand body that may bare at low tide (for example, breakpoint-bar, longshore bar).


Part of the beach that extends from the breakpoint-bar to the berm crest and is covered by the surf zone and swash. Syn: foreshore.


A sandy shorezone (barrier beach), island (barrier island), or spit (barrier spit) that extends roughly parallel to the coastal trend but is separated from the mainland by a relatively narrow body of water. Usu. contains sand dunes.

basal conglomerate

A coarse gravelly deposit of sand, pebbles, cobbles, or boulders forming the lowest member of strata that lie unconformably on a surface of erosion; esp. a coarse-grained beach deposit formed during a stillstand in sea level. Compare: conglomerate, wave-cut terrace. Syn: marginal conglomerate.


Dark-colored, mafic, fine-grained extrusive igneous rocks that are the fine-grained equivalent of gabbro. Basalt is the common material of oceanic crust and oceanic volcanoes.


(Coast) A curving, open indentation of a sea or lake into the land, usu between two headlands. A bay is larger than a cove and smaller than a gulf.


A zone covered by broken waves and unconsolidated deposits of wave worked material. It consists of the foreshore or bar-berm and the backshore. Syn: shore.

beach face

Sediment moved in sliding and rolling mode along the bed. Syn: contact load.


The sloping section of the beach normally exposed to wave swash; it occurs between the (low-tide) terrace and the berm crest.


General term for the rock, usu solid, that underlies soil or other unconsolidated, superficial material.


The nearly horizontal part of a beach that is adjacent to and above the beach face.

berm crest

Break in slope between the beach face and the berm; a position marking the highest runup of the swash.

biogenic coasts

Coasts where organic processes and organic growth dominate the shorezone. Typical examples include shorezones formed by coral reefs, serpulid reefs, oyster reefs, mangrove plants, and marsh grass.

boundary conditions

Requirements set at the boundaries of a system that insure that the flow of mass, momentum, and energy across those boundaries match with the gains or losses of those properties in the environment that surrounds the system. When the system boundaries are deformable, boundary conditions also require an accounting for the change in shape of the boundaries.


(Wave) A sea-surface wave that steepens and collapses, usu into a turbulent bore that crosses the surf zone and runs up the beach face. Waves shoal and break in water depths equal to or slightly greater than the height of the breaker.


A bar that is commonly at or near the breakpoint of the waves.