Coastal Landscapes as Systems: Dynamics, Processes, and Physical Factors

Vocabulary practice flashcards covering A-Level Geography concepts on coastal landscape systems, sediment cells and budgets, wave mechanics, tidal regimes, geological influence, and marine processes.

Coastal System

An open natural system driven by wave energy, comprised of interrelated inputs, processes (throughputs), stores (components), and outputs that constantly shape the shoreline.

Input

Material or energy moving into the coastal system from the outside, such as precipitation, solar energy, wind, or river sediment.

Output

Material or energy moving out of the coastal system into the surrounding environment, such as evaporation, ocean currents, and sediment carried out to deep water.

Stores (Components)

The individual parts or landforms of a coastal system where sediment is temporarily or permanently deposited, such as beaches, dunes, and sandbanks.

Flows (Transfers)

The links, processes, or pathways that move energy and sediment between components within a coastal system, such as longshore drift, mass movement, and wind-blown sand.

Positive Feedback

A mechanism within a system where an initial change or transfer triggers further changes in the same direction, amplifying growth or increase (such as coastal management causing increased erosion farther downdrift).

Negative Feedback

A self-regulating mechanism within a system where a transfer counteracts disturbance to decrease or decline change, restoring equilibrium (such as mass movement debris accumulating at a cliff foot and buffering it from marine erosion).

Dynamic Equilibrium

A state of balance within a constantly changing system, where inputs and outputs remain equal over time or negative feedback restores balance following a disturbance.

Sediment Cell

A stretch of coastline and its nearshore zone where the movement of coarse sediment is largely self-contained between major physical barriers such as headlands, functioning essentially as a closed system.

Sediment Budget

The calculation and balance of sediment inputs (gains like cliff erosion and fluvial delivery) versus outputs (losses like deposition into deep sinks or dredging) within a sediment cell.

Positive Sediment Budget (Surplus)

A state where the total volume of sediment entering a coastal system exceeds the sediment exiting, causing the shoreline to build outwards.

Negative Sediment Budget (Deficit)

A state where the total volume of sediment exiting a coastal system exceeds the sediment entering, resulting in net erosion and shoreline retreat.

Terrestrial Sediment

Sediment that originates from the land, accounting for approximately $95\%$ of global coastal sediment through fluvial deposition, cliff erosion, weathering, and mass movement.

Fluvial Deposition

The settling out and accumulation of sediment transported downstream by rivers and streams, typically occurring in estuaries and deltas.

Sub-aerial Processes

Land-based processes operating on the cliff face above high-water mark that alter the shape of the coastline, consisting of a combination of weathering and mass movement.

Weathering

The chemical, biological, and mechanical breakdown of rocks into smaller fragments and new minerals in situ (in place), without moving them.

Mass Movement

The downslope transfer of large volumes of rock and soil under the direct force of gravity, including rockfall, soil creep, landslides, mudflow, and slumping.

Marine Erosion

The wearing away and removal of coastal rock by wave action, particularly destructive waves operating through processes like hydraulic action and abrasion.

Aeolian Deposition

The accumulation of sediment that has been picked up, transported, and deposited by wind, commonly creating sand dunes.

Longshore Drift

The net lateral movement of sediment along a shoreline caused by waves approaching obliquely at an angle via swash and retreating perpendicular down the steepest beach gradient via backwash.

Beach Nourishment

An artificial coastal management intervention involving dumping or pumping dredged sand and gravel onto an eroding shoreline to create or widen a beach.

Fetch

The uninterrupted distance of open ocean water over which a wind blows to generate wave height and energy.

Wave Crest

The highest surface point of an individual wave.

Wave Trough

The lowest point of depression between two adjacent wave crests.

Wave Height

The vertical distance measured from a wave trough to the subsequent wave crest.

Wavelength

The horizontal distance measured between two successive crests or two successive troughs of a wave train.

Wave Breaking

The collapse of a wave that occurs when shoaling in shallow water causes the base to slow down via friction, transforming circular water orbits into ellipses until the wave crest overspills or plunges.

Constructive Wave

A low-energy, spilling wave with a long wavelength and low frequency that has a strong swash and weak backwash, leading to net sediment deposition and a gentle beach profile.

Destructive Wave

A high-energy, plunging wave with a short wavelength and steep profile formed by local storms, featuring a weak swash and powerful scouring backwash that removes sediment.

Wave Refraction

The bending of wave crests as they approach an irregular coast, caused by shallow water slowing waves near headlands while deep water maintains wave speed into bays, concentrating wave energy on headlands.

Tide

The periodic, regular rise and fall of ocean surface levels caused by the gravitational attraction of the Moon and Sun, combined with the Earth's rotation.

Tidal Range

The vertical height difference between consecutive high tide and low tide levels.

Lithology

The physical and chemical composition and characteristics of rock types, including mineral bonds, porosity, permeability, and hardness.

Geological Structure

The physical disposition and arrangement of rock formations, including faults, joints, folding, and the angle of dip of bedding planes relative to the coastline.

Concordant Coastline

A coastal configuration where bands of differing rock resistance run parallel to the shore, typically producing relatively straight coastlines or narrow cove entrances.

Discordant Coastline

A coastal configuration where alternating bands of hard and soft rock meet the sea at right angles, resulting in differential erosion that creates prominent headlands and sheltered bays.

Seaward-Dipping Strata

Rock bedding planes that slope downwards toward the ocean, facilitating rockslides and producing gentler, unstable cliff profiles.

Horizontally Bedded Strata

Rock strata oriented flat and parallel to the horizon, which produce steep, near-vertical cliff profiles prone to wave notching and toppling.

Landward-Dipping Strata

Rock beds that tilt inland away from the sea, creating relatively stable, steep cliffs where mass movement along bedding planes is prevented.

Ocean Current

A large-scale, continuous horizontal movement of ocean water at surface and depth, driven by wind patterns, solar heating, water density, and the Coriolis force.

Thermohaline Circulation

The deep ocean global conveyor belt driven by density gradients created by variations in surface water temperature and salinity, completing a global cycle over approximately $500$ years.

Rip Current

A strong, localized, and narrow flow of water that travels directly seaward from the shore through the breaker zone, often carving beach cusps.

Beach Cusps

Shoreline depositional formations featuring regularly spaced, crescent-shaped scalloped patterns of coarse sediment with seaward-pointing horns and rounded embayments.