JETTIES Shore-perpendicular structures built at the sides of an inlet to maintain navigable waterways. They stabilize an inlet by intercepting the longshore transport of sand that would otherwise fill it in or cause the channel to shift position. Jetties are often confused with groins, but are much longer and more substantial structures, usually built in pairs.

LITTORAL BUDGET Sediment budget of the beach consisting of sources and sinks.

LITTORAL DRIFT Sand and coarser material moved in the breaker and swash zones by waves and longshore currents along the shoreline.

LITTORAL SYSTEM Area from the landward edge of the coastal upland (usually the dune) to the seaward edge of the nearshore zone.

LONGSHORE CURRENT Current moving along (parallel to) the shore, generated by waves breaking at an angle to the shoreline.

LONGSHORE SEDIMENT TRANSPORT

Sediment transport along the beach (parallel to the shoreline) caused by longshore currents and/or waves approaching obliquely to the shoreline. See LITTORAL DRIFT.

MEAN SEA LEVEL The average elevation of the sea surface determined from tide gauges.

NEAP TIDE Small tide range, occurring at the first and third quarters of the moon, when the gravitational pull of the sun opposes that of the moon.

NEARSHORE Underwater area close to the beach, often characterized by sand bars, where sediment is actively being moved by waves and currents. This zone typically extends to a depth of 25 to 30 feet along the Atlantic coast.

NODAL POINT Location of longshore sediment transport divergence, where the littoral drift moves away in opposite directions along the coast. Normally areas of higher erosion rates.

NOR’EASTERS Extratropical storms with winds that commonly blow from the northeast, occur during the winter, and can generate large waves and elevated tides, resulting in considerable beach and dune erosion.

OBLIQUE WAVE APPROACH Waves that approach the beach at an angle (e.g., not straight-on) and generate longshore currents.

OFFSHORE Area seaward of the nearshore zone where sediment transport is only initiated by large swell waves or coastal storms.

OVERWASH Wave uprush overtopping the beach and dunes during storms; water and entrained sand that are moved landward of the dune. Also called an overwash surge during major events. See WASHOVER.

PEAT Dark-brown to black, fibrous material produced by plants which grow in marshes or bogs. When exposed on the beach face, it indicates long-term erosion and landward barrier migration.