Systems and processes Flashcards
What are the main components of a coastal system?
Inputs, Processes, Outputs
Inputs include energy (waves, tides, wind, currents), sediment (from rivers, cliffs, offshore sources), and human activity (coastal defences, dredging). Processes include erosion, transportation, deposition, and weathering. Outputs include landforms (beaches, spits, dunes, cliffs), sediment loss to deep water, and dissipation of wave energy.
What drives wave formation in coastal systems?
Wind energy, Fetch, Water depth
Stronger wind results in more powerful waves and determines fetch, affecting wave energy.
Define constructive waves.
Low height, long wavelength, strong swash, weak backwash
Constructive waves promote deposition.
Define destructive waves.
High height, short wavelength, weak swash, strong backwash
Destructive waves promote erosion.
What are spring tides?
Higher tidal range
Spring tides lead to more erosion.
What are neap tides?
Lower tidal range
Neap tides result in less energy.
What is longshore drift?
Waves approach at an angle, moving sediment laterally
It is a key process in sediment transport along the coast.
What is hydraulic action in marine erosion?
Air and water forced into cracks, breaking rock
It is one of the processes of marine erosion.
What is abrasion (corrasion)?
Waves throw sediment against cliffs, wearing them away
It contributes to the erosion of coastal landforms.
4 types of transportation ?
Traction, Saltation, Suspension, Solution
It is one of the methods of sediment transport.
What occurs when wave energy decreases?
Deposition
This leads to the formation of beaches, spits, bars, and dunes.
What are the types of weathering in sub-aerial processes?
Mechanical, Chemical, Biological
Mechanical includes freeze-thaw and salt crystallisation; Chemical includes carbonation and oxidation; Biological includes plant roots and burrowing animals.
What is slumping in mass movement?
Saturated cliffs collapse - section of soil or rock moves downhill along a curved, concave surface due to gravity.
It is a type of mass movement affecting coastal areas.
What is dynamic equilibrium in coastal systems?
Balance between erosion and deposition
It is crucial for maintaining coastal stability.
What effect does climate change have on coastal systems?
Rising sea levels, increased storm intensity
These changes can exacerbate coastal erosion and alter sediment transport.
What is wave refraction ?
Bending of waves as they approach the shore due to waves slowing down in shallow waters, leads to concentrated erosion.
Types of mass movement ?
Soil creep, Landslides, Rockfalls, Rotational slumping, Mudflows
What are aeolian processes ?
Transport and deposition of sediment by wind.
What is surface creep - Aeolian process ?
Wind rolls or slides sand grains along the surface.
What is saltation - Aeolian process ?
Where the wind is strong enough to temporarily lift grains into the airflow of heights up to 30 metres.
What is a landslide ?
Occur on cliffs made form softer rocks which slip as a result of lubrication usually following heavy rainfall.
What is a rockfall ?
Occur from cliffs undercut by the sea or on slopes affected by mechanical weathering.
What is a mudflow ?
Heavy rain causes large amount of fine material to flow downhill, soil is too saturated so surface layer become very fluid and flow downhill.
What is rotational slumping ?
When softer material overlies more resistant material.
What is soil creep ?
Occurs when there is a very slow continuous movement of individual soil particles downslope.
What is the sequence of development of sand dunes ?
Sand may become trapped by obstacles - First dunes to develop are embryo dunes and are suitable for colonisation - Upwards growth of embryo dunes raises height of them creating foredunes ( yellow dunes ) - Dunes gradually become fixed as more vegetation colonises - In places dune slack occur which are low-lying areas which can flood - Behind yellow and grey dunes the supply is cut off giving smaller dune features.
What is the concept of sediment cells ?
Sediment cells are sections of the coastline that are treated as distinct, self-contained systems for the movement of sediment. They are areas where the movement of sand, pebbles, and other materials along the shore (known as sediment transport) is largely contained within that cell, meaning sediment entering the system in one part of the cell is likely to stay within it and not be carried to other cells.
What is a sediment budget ?
How much sediment in a sediment cell
What are igneous rocks ?
More resistant rocks which form steep slopes
What geology and lithology do steep cliffs have ?
Horizontal or vertical geology and lithology not diagonal.
What is a driving process in the formation of sand dunes and why ?
Aeolian processes as there needs to be a plentiful supply of sand, sand needs to be dry enough to be picked up, Strong onshore winds, Surface creep or saltation.
What is the process for the formation of a salt marsh ?
Extremely sheltered areas where freshwater mixes with seawater and causes negatively charged suspended clay particles to be neutralised by cations in the seawater which causes clays to settle. After clays settle microscopic and macroscopic algae grows and then the height of the salt marsh increases where vegetation succession can occur.
What is the halosere ?
Term for a salt marsh
What are halophytic species ?
Species that can cope with being underwater like spartina (cordgrass).
What is the expected sea level rise by 2100 ?
Up to 1 metre
