IGCSE Edexcel Geography-Coastal Environments

Key terms

Swash

The forward movement of water that runs up the beach at prevailing wind direction

Backwash

The water that runs back down the beach at perpendicular angle under gravity.

Waves

A ridge of water formed by the circular movement of water near the surface of the sea caused by the wind.

Wave action

erosion, transport and deposition caused by waves on the coast

Fetch

distance over which wind blow across sea surface

Destructive/erosional Waves

The backwash is stronger than the swash therefore material is dragged back down the beach and moved along the coast.

Constructive/depositional Waves

The swash is stronger than the backwash therefore the material is moved up the beach and forms sandy beaches

Longshore Drift

The movement of loose sediments along the coast by wave action due to prevailing winds.

Deposition

The dropping of material that was being carried by a moving force, such as waves.

Hydraulic Action

Force of the waves hitting the cliffs and forcing pockets of air in cracks, leading to minor explosions when waves retreat

Abrasion

Waves picking up stones and hurling them at cliffs at high velocity, wearing the cliffs away.

Corrosion

Dissolving of rocks by sea water.

Attrition

Material carried by the waves becomes rounded and smaller over time as it collides with other material.

Traction

Large particles like boulders are pushed along the seabed by rapid currents

Saltation

The bouncing movement of smaller particles caused by fast flowing water

Suspension

Fine light material is carried along in the water.

Solution

Dissolved rocks transport as chemical solution

Sub-aerial processes

The general re-shaping of the land by normal atmospheric processes, for example wind and rain. It includes weathering, mass movement, erosion and deposition.

Erosion

Wearing away of rocks by wind and rain

Weathering

Breakdown of rocks which is caused by freeze-thaw, growth of salt crystals (physical weathering), acid rain (chemical weathering) and the growth of vegetation roots (biological weathering)

Mass Movement

Removal of cliff face material under the influence of gravity in the form of rock falls, slumping and landslides.

Erosional landforms

landforms of alternations of headlands and bays shaped by destruction waves

Concordant Coasts

A coastline created when alternating hard and soft rocks occur parallel to coast and are eroded at different rates

Discordant Coasts

A coastline created when alternating hard and soft rocks occur perpendicular to the coast and eroded at different rates.

wave-cut platform

a rocky, level area at or around sea level representing the base of old and now retreated cliffs

wave-cut notch

a hollow eroded by the impact of waves at the foot of a cliff

Headlands

A rocky coastal promontory of more erosion resistant rocks lying between bays of less resistant rocks

Cliff

a steep face of rock caused by the repeatedly breaking of destructive waves

Bay

A wide coastal inlet that is open to the sea.

Cave

A void in a cliff where rock materials have been removed by erosion

Arch

If the cave is enlarged and extends back through to the other side of the headland, possibly meeting another cave, an arch is formed.

Stack

An isolated pilar of rock left when the top of the arch has collapsed due to continuous erosion

Stump

Further erosion at the base of the stack may eventually cause it too to collapse leaving a small, flat portion of the original stack as a stump which may only be visible at low tide.

Beach

An accumulation of coastal sediments, deposited between storm-beach area and low-tide marks and acts as a natural protection to the coastline

Spits

A depositional landform formed when a finger of sediment of sand and shingle extends from the shore to the sea, often at a river mouth and usually curved.

Flocculation

The process in which small particles in water coagulate in brackish water

Brackish water

mixture of fresh and salt water

Bar

A linear depositional beach-like landform formed when a spit joins two headlands

Tombolos

Extensions of spit which joins the mainland to an island e.g. Chesil Beach

Lagoon

a body of water cut off from a larger body by a reef of sand or coral

Cuspate foreland

Triangular-shaped accumulations of sand and shingle that extends seawards and are developed due to longshore-drift from 2 directions e.g. Dungeness

Vegetation - factor affecting coastal environments

The building up and support with roots helps stabilising sand dunes or cliffs e.g. Marram grass in sand dune

Sea level change

The rise or fall in the average level of sea over long periods of time

Rise- submerged coastline forming rias and fiords

Fall- emerged coastline forming relict cliffs and raised beaches

Biodiversity

Number and variety of living species found in a given are or ecosystem.

Ecosystem

Community of plants and animals that interact with each other and their physical environment.

Coral reef

A ridge of rock in the sea formed by the growth and deposit of coral e.g. Great Barrier Reef

Mangroves

Tropical and sub-tropical coastal forests and can grow in salty, tidal water e.g. Sundarbans

Salt Marsh

A tidal ecosystem in estuaries and deltas consisting of mudflats with salt tolerant grasses and flowers

Sand Dunes

Coastal sand hills above the high tide mark covered with grasses and shrubs

plant succession

The sequences of changes in a plant community over time

Nutrient cycle

Continuous flow of nutrients into and out of stores in the ecosystem; balanced, unless disturbed by human activity

Goods

Material resources that can be extracted and used

Services

General benefits and advantages

Sediment budget

a balance between the input of sediments arriving a beach and the output of sediments leaving the beach

Development

Making use of the coast for a variety of purposes such as tourism, housing, shipping and industry.

Coastal cell

A section of the coastline where moving sediments from one part of the cell will affect another area of that cell

Environment Agency

Use coastal cell when considering coastal management strategies and make decisions based on Cost-benefit analysis

Conservation

Protection of aspects of the environment for the future benefit of people.

Hard Enginerering

The use of concrete and large artificial structures by civil engineers to defend land against natural erosion processes

Soft Engineering

Managing erosion by working with natural processes to help restore beaches and coastal ecosystems

Managed retreat

Allowing low lying areas of low land value along the coast to be flooded in a controlled way.

Sea wall

A concrete wall which aims to prevent erosion of the coast by providing a barrier which reflects wave energy.

Groynes

Wooden or concrete barriers at right angles to the beach

Rip Rap (Rock Armour)

large rocks placed at the base of a cliff/sea wall.

Gabions

Steel mesh cages filled with small rocks, absorb wave energy.