S1, 2a and 3 (Everything but CS)

• Why can coastal landscapes be viewed as open systems?

  Energy and matter can be transferred from neighbouring systems as an input + transferred to neighbouring systems as an output
• What are the components of an open system?

  1. Inputs
  2. Outputs
  3. Processes
  4. Stores
• What is a state of equilibrium in a system?

  When inputs and outputs are equal
• What is dynamic equilibrium in a coastal system?

  When the equilibrium is disturbed, system goes under self-regulation and changes its form in order to restore the equilibrium - system produces its own response to the disturbance
• What type of feedback is dynamic equilibrium an example of?

  Negative - an automatic response that restores equilibrium
• What is a sediment cell?

  A stretch of coastline and its associated nearshore area within which the movement of coarse sediment, sand and shingle is largely self-contained
• How many large sediment cells are there around England and Wales?

  11
• What are the boundaries of sediment cells determined by?

  Topography and shape of the coastline
• Why are sediment cells generally regarded as a closed system?

  Suggests that no sediment is transferred from one cell to another - held within the headlands (barriers)
• Why, in reality, is it unlikely that sediment cells are completely closed?

  1. Variations in wind direction and presence of tidal currents = inevitable that some sediment is transferred between neighbouring cells
  2. Many sub-cells of a smaller scale exist within the major cells
• How does wind influence coastal systems?

  1. Winds are the source of energy for waves
  2. Wind direction can influence the impact of waves (oblique waves = LSD)
  3. Aeolian processes can erode or transport and deposit sediment
• Describe the anatomy of a wave?

  1. Crest - highest surface part of the wave
  2. Trough - lowest part
  3. Wave height - vertical distance between trough and crest
  4. Wavelength - horizontal distance between 2 adjacent crests/troughs
• What is the difference between swell and storm waves?

  Swell waves - longer wavelength, wave period of ~20s

  Storm waves - short wavelength, greater height and shorter wave period
• Describe the process of a breaking wave?

  1. Wave move into shallow water
  2. Wave slow down (friction)
  3. Wavelength decreases = successive waves bunch up
  4. Deepest part of wave slows down more than the top
  5. Wave steepens - crest advances ahead of base
  6. When water depth is less than 1.3x wave height, wave topples over and breaks against shore
• Describe a constructive wave?

  • Low in height, long wavelength, low frequency
  • Break by spilling forwards, strong swash travels a long way up gently sloping beaches
  • Long wavelength = backwash returns to sea before next wave breaks = next swash movement is uninterrupted and thus retains its energy
• Describe a destructive wave?

  • Greater height, shorter wavelengths and a higher frequency
  • Break by plunging downwards = little forward transfer of energy to move water up the steeply sloping beach as friction slows swash, so wave does not travel far
  • Short wavelength = swash of next wave often slowed by the frictional effects of meeting the returning backwash of the previous wave
  • Swash energy is less than backwash energy
• What produces tides?

  • The gravitational pull of the moon, and to a lesser extent, the sun
  • The moon pulls water towards it, creating a high tide
• What is a spring tide AND what happens during it?

  When the moon, sun and earth are aligned = Higher high tides and lower low tides
• What is a neap tide AND what happens during?

  Moon and sun at right angles to each other = Lower high tides and higher low tides
• How does tidal range influence coastal landscapes?

  • In enclosed areas (Mediterranean) - tidal range are low (microtidal) and so wave action is restricted to a narrow area of land
  • In areas where coast is funnelled (Severn Estuary) - tidal ranges can be as high as 14m (macrotidal)
• What is meant by lithology?

  Chemical and physical composition of rocks
• How are coastal systems influenced by lithology?

  Differences in rock lithology = varying levels of susceptibility to erosion, weathering and mass movements = formation of different coastal formations
• What is meant by structure in regards to geology?

  • Structure concerns the properties of individual rock types such as jointing, bedding and faulting
  • Also includes the permeability of rocks
• What is meant by porous rocks?

  Rocks which contain pores of air spaces between mineral particles, where water is stored
• What is meant by permeable?

  A type of rock that is penetrated by water, either through mineral pores or along joints, faults and fissures
• How does structure influence coastal landscapes?

  1. Important influence on the planform of coasts at regional scale: e.g. rock outcrops that run parallel to coast = straight coastlines (concordant), rocks that lie at right angles to the coast create discordant coastlines - more resistant rocks for headlands, weaker rocks for bays
  2. Influence on cliff profiles: horizontally bedded/landward dipping = steep vertical cliff profiles, strata/seaward dipping = profiles tend to follow the angle of bedding plane (dip)
• How are ocean currents generated?

  Generated by the Coriolis effect and convection, and are set in motion by the movement of winds across the water surface
• How do ocean currents influence coastal landscapes?

  Strength of the current = limited impact in terms of geomorphic processes (driven by offshore winds = less effect on coastal landscapes) but the transfer of heat energy = significant, directly affects air temperature, therefore sub-aerial processes
• What is terrestrial sediment?

  Sediment from land
• What are the main sources of sediment input?

  Rivers - some locations, as much as 90% of coastal sediment comes from rivers
• What is the origin of terrestrial sediment?

  Erosion of inland areas by water, wind and ice as well as sub-aerial processes (weathering and mass movement)
• What are the other sources of terrestrial sediment

  1. Wave erosion
  2. Cliff erosion - increased by rising sea levels and amplified by storm surge events - erosion of weak cliffs in high energy wave environments contributes as much as 70% of the overall material supplied to beaches
  3. LSD
• What type of waves bring sediment to the shore from offshore location and deposit it

  Constructive waves
• What also brings sediment to the shore from offshore locations?

  1. Tides
  2. Currents
  3. Wind - blows sediment from other locations (exposed sand bars, dunes and beaches along the coast) - material is generally fine sand
• What is a way in which sediment equilibrium can be maintained?

  Beach nourishment
• How can beach nourishment occur?

  1. Sediment brought in a lorry and dumped on the beach before spread by bulldozers
  2. Sand and water can be pumped onshore by pipeline from offshore sources
• What is weathering?

  The use of energy to produce physically or chemical altered materials from surface or near surface rocks
• The breakdown of rock is largely achieved by which weathering process?

  Physical weathering processes
• What doesn't take place during physical weathering?

  Chemical alterations
• How does physical weathering allow for more weathering to take place?

  Increase the exposed surface area of the rock