Key Words Flashcards
Landscape
An extensive area of land regarded as being visually and physically distinct
Abrasion (or corrasion)
The wearing away of cliffs by sediment flung by breaking waves
Arch
A wave-eroded passage through a small headland. This begins as a cave formed in the
headland, which is gradually widened and deepened until it cuts through.
Attrition
Erosion caused when rocks and boulders transported by waves bump into each other and
break up into smaller pieces.
Bar
Where a spit grows across a bay, a bay bar can eventually enclose the bay to create a lagoon. Bars can also form offshore due to the action of breaking waves
Beach
The zone of deposited material that extends from the low water line to the limit of storm
waves. The beach or shore can be divided in the foreshore and the backshore.
Beach nourishment
The addition of new material to a beach artificially, through the dumping of large amounts of sand or shingle.
Beach reprofiling
Changing the profile or shape of the beach. It usually refers to the direct transfer of material
from the lower to the upper beach
Cave
A large hole in the cliff caused by waves forcing their way into cracks in the cliff face.
Chemical weathering
The breakdown of rock caused by a chemical change within that rock; seawater can cause chemical weathering of cliffs.
Cliff
A steep high rock face formed by weathering and erosion along the coastline.
Deposition
Occurs when material being transported by the sea is dropped due to the sea losing energy.
Dune regeneration
Action taken to build up dunes and increase vegetation to strengthen the dunes and prevent excessive coastal retreat. This includes the re-planting of marram grass to stabilize the dunes, as well as planting trees and providing boardwalks.
Erosion
The wearing away and removal of material by a moving force, such as a breaking wave.
Gabion
Steel wire mesh filled with boulders used in coastal defences
Groyne
A wooden barrier built out into the sea to stop the longshore drift of sand and shingle, and so
cause the beach to grow. It is used to build beaches to protect against cliff erosion and
provide an important tourist amenity. However, by trapping sediment it deprives another
area, down-drift, of new beach material.
Hard engineering
The use of concrete and large artificial structures by civil engineers to defend land against natural erosion processes.
Headlands and bays
A rocky coastal promontory made of rock that is resistant to erosion; headlands lie between
bays of less resistant rock where the land has been eroded back by the sea.
Hydraulic power
The process by which breaking waves compress pockets of air in cracks in a cliff. The pressure may cause the crack to widen, breaking off rock.
Longshore drift
The zigzag movement of sediment along a shore caused by waves going up the beach at an oblique angle (wash) and returning at right angles (backwash). This results in the gradual
movement of beach materials along the coast.
Managed retreat
Allowing cliff erosion to occur as nature taking its course: erosion in some areas, deposition in others. Benefits include less money spent and the creation of natural environments. It may involve setting back or realigning the shoreline and allowing the sea to flood areas that were previously protected by embankments and seawalls.
Mass movement
The downhill movement of weathered material under the force of gravity. The speed can vary
considerably
Mechanical weathering
Weathering processes that cause physical disintegration or break up of exposed rock without any change in the chemical composition of the rock, for instance freeze thaw.
Rock armour
Large boulders dumped on the beach as part of the coastal defences.
Sand dune
Coastal sand hill above the high tide mark, shaped by wind action, covered with grasses and shrubs.
Sea wall
A concrete wall which aims to prevent erosion of the coast by providing a barrier which
reflects wave energy.
Sliding
Occurs after periods of heavy rain when loose surface material becomes saturated and the
extra weight causes the material to become unstable and move rapidly downhill, sometimes in an almost fluid state.
Slumping
Rapid mass movement which involves a whole segment of the cliff moving down-slope along a saturated shear-plane or line of weakness.
Soft engineering
Managing erosion by working with natural processes to help restore beaches and coastal ecosystems.
Spit
A depositional landform formed when a finger of sediment extends from the shore out to sea,
often at a river mouth. It usually has a curved end because of opposing winds and currents.
Stack
An isolated pillar of rock left when the top of an arch has collapsed. Over time further erosion reduces the stack to a smaller, lower stump.
Transportation
The movement of eroded material.
Wave cut platform
A rocky, level shelf at or around sea level representing the base of old, retreated cliffs
Waves
Ripples in the sea caused by the transfer of energy from the wind blowing over the surface of the sea. The largest waves are formed when winds are very strong, blow for lengthy periods and cross large expanses of water.
Abrasion
Rocks carried along by the river wear down the river bed and banks.
Attrition
Rocks being carried by the river smash together and break into smaller, smoother and
rounder particles
Cross profile
The side to side cross-section of a river channel and/or valley
Dam and reservoir
A barrier built across a valley to interrupt river flow and create a reservoir which stores water and controls the discharge of the river.
Discharge
The quantity of water that passes a given point on a stream or riverbank within a given period of time.
Embankments
Raised banks constructed along the river; they effectively make the river deeper so it can hold
more water. They are expensive and do not look natural but they do protect the land around them.
Estuary
The tidal mouth of a river where it meets the sea; wide banks of deposited mud are exposed at low tide.
Flood
Occurs when river discharge exceeds river channel capacity and water spills out of the
channel onto the floodplain and other areas.
Flood plain
The relatively flat area forming the valley floor on either side of a river channel, which is
sometimes flooded.
Flood plain zoning
This attempts to organise the flood defences in such a way that land that is near the river and often floods is not built on. This could be used for pastoral farming, playing fields etc. The areas that rarely get flooded would therefore be used for houses, transport and industry.
Flood relief channels
Building new artificial channels which are used when a river is close to maximum discharge.
They take the pressure off the main channels when floods are likely, therefore reducing flood
risk.
Flood risk
The predicted frequency of floods in an area
Flood warning
Providing reliable advance information about possible flooding. Flood warning systems give
people time to remove possessions and evacuate areas.
Fluvial processes
Processes relating to erosion, transport and deposition by a river.
Gorge
A narrow, steep sided valley, often formed as a waterfall retreats upstream.
Hard engineering
Involves the building of entirely artificial structures using various materials such as rock, concrete and steel to reduce, disrupt or stop the impact of river processes.
Hydraulic action
The force of the river against the banks can cause air to be trapped in cracks and crevices. The pressure weakens the banks and gradually wears it away.
Hydrograph
A graph which shows the discharge of a river, related to rainfall, over a period of time.
Interlocking spurs
A series of ridges projecting out on alternate sides of a valley and around which a river winds its course
Lateral erosion
Sideways erosion by a river on the outside of a meander channel. It eventually leads to the
widening of the valley and contributes to the formation of the flood plain.
Levees
Embankment of sediment along the bank of a river. It may be formed naturally by regular
flooding or be built up by people to protect the area against flooding
Long profile
The gradient of a river, from its source to its mouth.
Meander
A pronounced bend in a river.
Ox-bow lake
An arc-shaped lake which has been cut off from a meandering river.
Precipitation
Moisture falling from the atmosphere
Saltation
Particles bouncing down the river bed.
Soft engineering
Involves the use of the natural environment surrounding a river, using schemes that work
with the river’s natural processes. Soft engineering is usually much cheaper and offers a more
sustainable option as it does not interfere directly with the river’s flow.
Solution
Soluble particles are dissolved into the river.
(Channel) straightening
Removing meanders from a river to make the river straighter. Straightening the river allows it to carry more water quickly downstream, so it doesn’t build up and is less likely to flood.
Suspension
Fine solid material held in the water while the water is moving
Traction
The rolling of boulders and pebbles along the river bed.
Vertical erosion
Downward erosion of a river bed.
Waterfall
Sudden descent of a river or stream over a vertical or very steep slope in its bed. It often
forms where the river meets a band of softer rock after flowing over an area of more resistant material.
