Coastal Systems and Processes

Vocabulary flashcards generated from the coastal geography lecture notes covering coastal inputs, littoral zones, wave mechanics, tides, currents, feedback loops, and coastal landforms.

Open system (Coastal)

A system where inputs come from outside, flow through stores and processes, and leave as outputs.

Input (Coastal system)

Energy or matter added to the coastal system.

Output (Coastal system)

Energy or matter removed from the coastal system.

Store (Coastal system)

A location where energy or matter is held within the coastal system.

Flow

A transfer or linkage between stores within a system.

Marine inputs

Coastal inputs originating from the sea, including waves, tides, and salt spray.

Atmospheric inputs

Coastal inputs originating from the atmosphere, including wind, pressure, precipitation, and sun.

Terrestrial inputs

Coastal inputs originating from land, including weathering, erosion, and rock type.

Human inputs

Coastal inputs resulting from human activity, including pollution, recreation, settlement, and defences.

Erosional landforms

Coastal features created by erosion, including cliffs, wave-cut platforms, caves, arches, stacks, stumps, headlands, and bays.

Depositional landforms

Coastal features created by sediment accumulation, including beaches, spits, bars, tombolos, dunes, and salt marshes.

Littoral zone

The coastal zone ordered from shore to sea as Backshore (above high tide, storms only), foreshore (HWM to LWM), inshore, nearshore (waves begin to break), and offshore.

Backshore

The upper part of the littoral zone above high tide that is reached only during storms.

Foreshore

The section of the littoral zone located between the high water mark (HWM) and low water mark (LWM).

Nearshore

The region of the littoral zone where waves begin to break.

Wind

The movement of air from high pressure to low pressure.

UK prevailing wind

Wind blowing from the SW across the Atlantic, providing huge energy potential to the UK coastline.

Frictional drag

The mechanism by which wind transfers energy across the sea surface to form waves.

Fetch

The distance of open water over which the wind blows uninterrupted.

Aeolian transport

Wind-driven movement of sand that accumulates to build coastal dunes.

Wave crest

The highest point of a wave.

Wave trough

The lowest point of a wave.

Wavelength

The horizontal distance between two consecutive wave crests.

Wave height

The vertical distance from a wave's trough to its crest.

Wave period

The time interval between successive wave crests passing a fixed point.

Wave breaking

The process where friction with the sea bed slows the wave base in shallow water while the top continues faster, causing the wave to steepen, tip, and plunge.

Constructive waves

Waves with low frequency ($6$ to $8$ per min), low height and long length, elliptical orbital motion, strong swash, and weak backwash that deposit material to build beaches, spits, and bars.

Destructive waves

Waves with high frequency, tall and steep shape, circular orbital motion, weak swash, and strong backwash that remove material and erode the coastline.

Wave refraction

A negative feedback process where shallow water at headlands slows waves, causing them to bend and converge (increasing wave height and energy), while in deeper bays waves diverge (reducing energy and depositing sediment), straightening the coast over time.

Tides

The periodic rise and fall of sea levels caused by the gravitational attraction of the moon and sun.

Spring tides

Tides formed when the sun, moon, and Earth align during a new or full moon, producing the highest high tides, lowest low tides, and the largest tidal range.

Neap tides

Tides formed when the sun and moon are at $90^\text{ degrees}$ relative to Earth, resulting in the smallest tidal range.

Micro-tidal range

A tidal range that is under $2\,m$.

Meso-tidal range

A tidal range between $2\,m$ and $4\,m$.

Macro-tidal range

A tidal range that exceeds $4\,m$.

Tidal bore

A wave created in funneled estuaries, such as the Severn Estuary where it can reach up to $1\,m$ high.

Storm surge

A rise in sea level caused by low atmospheric pressure and strong onshore winds pushing water ashore, occurring with maximum impact at high tide.

Currents

Permanent or seasonal movements of ocean surface water.

Longshore drift

The process where waves approaching the shore at an angle push sediment up the beach via swash and backwash carries it back perpendicular via gravity, causing zigzag transport along the coast.

Ebb tidal current

A tidal flow moving from land to sea that carries sediment away from the coast.

Flood tidal current

A tidal flow moving towards land that brings sediment onto the shore.

Rip currents

Narrow, powerful streams of water flowing back out to sea through gaps in sandbars at speeds up to $8\,km/h$.

Upwelling

The movement of cold deep water rising to replace warm surface water as part of global ocean circulation.

Dynamic equilibrium

A state in a coastal system where inputs balance outputs so stores remain stable, which can be disrupted by events like storms, sea level rise, or human actions.

Negative feedback

A process where initial system changes trigger self-regulating responses that nullify effects, returning the system to balance and slowing change.

Positive feedback

A process where initial system changes are amplified and multiplied, accelerating the rate of change.

High energy coast

A coastline exposed to powerful waves, long fetch, and destructive wave action, where erosion dominates to create features like cliffs, headlands, platforms, and steep shingle beaches.

Low energy coast

A sheltered coastline characterized by short fetch, bays, and constructive waves, where deposition dominates to form sand beaches, spits, bars, and salt marshes.

Assess (Essay command)

An essay instruction requiring the student to weigh up several factors or options and reach a supported conclusion regarding their effectiveness.