Coasts: All EGC & PMT FCs Flashcards
Abrasion
Sediment dragged over rocky surfaces smooths and erodes rock like sandpaper.
Attrition
Rocks and pebbles collide, breaking into smaller, smoother particles.
Backshore
The area of a beach that lies between the high-water mark (HWM) and the limit of wave activity. It is the upper beach closest to and including any cliffs or sand dunes.
Beach Morphology
The surface shape of the beach
Beach profile
The steepness and width of a beach. The profile of beaches changes over time.
Coastal processes
The mechanisms that operate on the inputs and result in particular outputs, shaping coastlines.
Coastal Recession
The retreat of a coastline due to erosion, sea-level rise or submergence.
Concordant coastline
Coastlines with rock bands parallel to the shore, forming coves like Lulworth Cove.
Constructive waves
Waves that add sediment to a beach as the swash pushes more material from offshore up the beach than the backwash removes.
Corrasion
Material picked up by waves is hurled at cliffs, chipping away at rock.
Currents
The permanent or seasonal movement of surface water in the seas and oceans.
Dalmation Coast
A concordant coastline with several river valleys running perpendicular to the coast. They become flooded to produce parallel long islands and long intels.
DEFRA’s 1:1 Cost-Benefit Analysis
The evaluation of a coastal town’s economic value compared to the cost of management required. Costs are tangible and intangible and can be economic or other costs like visual impacts.
Deposition
When wave energy drops, sediment is deposited, forming sediment sinks.
Destructive waves
Waves that remove beach material from the shoreline as the backwash is more forceful than the swash.
Dip
The slope of rock layers, affecting cliff formations.
Discordant coastline
Coastlines with rock bands at right angles to the shore, forming headlands and bays.
Dynamic environment
One that is ever changing.
Dynamic equilibrium
A state of balance where coastal inputs equal outputs in a system that is constantly changing. Where coastal erosion and deposition are balanced there will be a state of dynamic equilibrium.
Emergent coast
A coastline that is advancing relative to the sea level at the time.
Erosion
The wearing away of the Earth’s surface and removal of material by wind, waves, tides, and sea currents.
Eustatic
Global changes to the sea levels.
Fault line
Cracks in rock formed by tectonic movement, creating areas of weakness.
Fetch
The length of water over which a wind has blown. The larger the fetch, the bigger the waves.
Fjord
A long narrow inlet deeper in the middle section that at the mouth. It is created when sea levels rise relative to the land, flooding coastal glacial valleys.
Foreshore
The area of a beach that lies between the high-water mark and the low-water mark (LWM). It is the lower part of the beach and is covered at high tide.
Freeze Thaw
A form of physical sub-aerial weathering where water freezes in the cracks of a rock, expands and enlarges the crack and therefore weakens it.
Geology
The rock composition of an area, including lithology (rock type) and structure (arrangement of rocks).
Glacial erosion
A necessary part of the formation of Fjords. It is the removal of loose material by glacier ice.
Grading
The layering of sediments based on their size.
High-energy coastlines
Coastlines experiencing strong, powerful waves with high erosion rates.
Hydraulic action
Waves compress air in rock cracks, creating pressure that weakens cliffs.
Impermeable
A rock that does not allow rainwater to pass through.
Inputs
These include energy from waves, wind, tides, sea currents and gravity; sediment; sea level change and geology.
Integrated Coastal Zone Management (ICZM)
Large sections of coastline (often sediment cells) are managed with one integrated strategy and management occurs between different political boundaries.
Isostatic
A change in local coastline or land height relative to sea level
Littoral Cell
A section of the coast, within which involves much sediment movement. A littoral cell is not a closed system.
Longshore currents
These occur when waves approach the coastline at an angle, transporting sediment parallel to the coast.
Longshore drift
Zigzag movement of sediment along the coast due to swash and backwash.
Low-energy Environment
A coast where wave action is predominantly small constructive waves, causing deposition and leading to beach accretion.
Marine processes
Processes operating on coastlines, including erosion, transport, and deposition.
Mass movement
The movement of material downhill by gravity assisted by rainfall.
Neap tide
Occurs when the Sun and Moon are at right angles, causing a smaller tidal range.
Nearshore
The area before the shore where the wave steepness and breaks before they reach the shore and then reform before breaking on the beach. It extends from the low-tide zone and then out to sea.
Nearshore
Also called the inshore, this is the area of a beach between the low water mark and the point of the coast where waves no longer have any effect.
Negative feedback
When a change in the system causes other changes that have the opposite effect. This dampens the initial change and restores balance in a system.
Offshore
The area of a beach that is beyond the point where waves cease to impact upon the seabed.
Open system
Inputs (energy and matter) come from outside the system, and outputs leave the system, e.g. sediment is carried onto a coastline from further down the coast and eroded rock is washed offshore out into the ocean.
Outputs
These include dissipation of wave energy; accumulation of sediment above the tidal limit e.g. sand dunes; sediment removed from sediment cell e.g. carried out to sea.
Permeable
A rock that allows rainwater to pass through it.
Plant Succession
Change to a plant community due to growing conditions adapting (eg. sand dunes and salt marshes).
Positive feedback
When a change in the system causes other changes that have a similar effect so that the initial change is enhanced.
Prevailing wind
The direction from which the wind most usually blows from. In the UK it’s from the southwest.
Ria
Narrow winding inlet which is deepest at the mouth, formed when sea levels rise causing coastal valleys to flood.
Rip currents
Strong localised underwater currents that move water away from the coastline just below the surface.
Saltation
Smaller sediment bounces along the sea bed, being pushed by currents.The sediment is too heavy to be picked up by the flow of the water.
Sediment budget
The balance between sediment being added to and removed from a sediment cell coastal system.
Sediment Cell
Sections of the coast bordered by prominent headlands. Within these sections, the movement of sediment is almost contained and the flows of sediment should act in dynamic equilibrium.
Sediment sink
Where sediment is permanently lost to the coastal system, e.g., offshore currents may transfer sediment out to sea.
Sediment sources
Sediment comes from rivers, streams, cliff erosion, longshore drift, wind, and offshore.
SMP
Identifies all of the activities, both natural and human which occur within the coastline area of each sediment cell and then recommends a combination of four actions for each stretch of that coastline: Hold the Line, Advance the Line, Managed Realignment and No Active Intervention.
Solution (transport)
Dissolved materials transported in water, important in the carbon cycle.
Spring tide
Occurs when the Sun and Moon are aligned, causing higher high tides and lower low tides, resulting in a greater tidal range.
Stores
An accumulation of sediment - landforms e.g. beach.
Subaerial Processes
The combination of mass movement and weathering that affects the coastal land above sea.
Submergent Coast
A coast that is sinking relative to the sea level of the time.
Suspension
Fine sand and silt carried by moving water, creating a murky appearance.
Tidal range
The relative difference in height between high and low tides, affecting erosion and deposition.
Tides
Long-period waves caused by the gravitational pull of the moon and the Sun.
Till
Deposits of angular rock fragments in a finer medium.
Traction
Large stones rolled along the seabed by waves.
Transfer or flow
Sediment is moved from one place to another as a result of processes such as longshore drift and rip currents.
Transportation processes
The movement of sediment by waves and tides.
Upwelling
The movement of cold water from deep in the ocean towards the surface, replacing warmer surface water.
Wave pounding
The sheer force of water impacting rock surfaces, weakening and dislodging pieces.
Wave refraction
What happens to waves when they approach uneven coastlines, causing erosion on headlands and deposition in bays.
Weathering
The breakdown or decay of rock at or near the Earth’s surface, in its original position (in situ).
