Coasts

• What type of system is the coast described as?

  Open system
• What does the coastal system receive from outside?

  Inputs
• What types of systems can the coast transfer outputs to?


  Terrestrial, atmospheric, or oceanic
• What cycles are included in the coastal system?

  Rock, water, and carbon cycles
• What are sections of the coast called?

  Sediment cells
• What is the movement of sediment within sediment cells described as?

  Almost contained
• What can upset the dynamic equilibrium of sediment movement?

  Human interventions and natural variations
• What are smaller sections within sediment cells called?

  Subcells
• What are the main inputs to the coastal system?

  • Marine: Waves, Tides, Salt Spray
  • Atmosphere: Sun, Air Pressure, Wind Speed and Direction
  • Humans: Pollution, Recreation, Settlement, Defences
• What are the main outputs of the coastal system?

  • Ocean currents
  • Rip tides
  • Sediment transfer
  • Evaporation
• What are the stores/sinks in the coastal system?

  • Beaches
  • Sand Dunes
  • Spits
  • Bars and Tombolos
  • Headlands and Bays
  • Nearshore Sediment
  • Cliffs
  • Wave-cut Notches
  • Wave-cut Platforms
  • Caves
  • Arches
  • Stacks
  • Stumps
  • Salt Marshes
  • Tidal Flats
  • Offshore Bands and Bars
• What processes link inputs, outputs, and stores in the coastal system?

  • Wind-blown sand
  • Mass-movement processes
  • Longshore drift
  • Weathering
  • Erosion (Hydraulic Action, Corrosion, Attrition, Abrasion)
  • Transportation (Bedload, In suspension, Traction, In solution)
  • Deposition (Gravity Settling, Flocculation)
• What are the sources of energy in the coastal system?

  • Wind
  • Gravitational
  • Flowing Water
• What accounts for the majority of sediment in the coastal zone?

  Rivers
• Where is sediment often deposited in rivers?

  Estuaries
• Why is cliff erosion significant in coastal areas?

  Unconsolidated cliffs erode easily
• When does most cliff erosion occur?

  During winter months
• How does wind contribute to sediment transport?

  Blows sand along or up a beach
• What happens when glaciers calve?

  They deposit sediment stored in ice
• How is sediment transferred to the coastal zone?

  Waves, tides, and currents erode offshore sinks
• What is longshore drift?

  Movement of sediment along the beach
• What is a sediment budget?

  • Uses data of inputs, outputs, stores, and transfers
  • Assesses gains and losses of sediment
  • Operates in dynamic equilibrium
• What is the littoral zone?

  Area between cliffs or dunes and offshore
• What factors cause changes in the littoral zone?

  Short-term and long-term factors
• What is the primary source of energy for natural systems?

  The sun
• What is the main energy source at the coast?

  Waves formed offshore
• How are waves formed?

  Wind moves across the water surface
• What happens to water particles as waves approach the coastline?

  They move in circular orbital motion
• What occurs as the seabed becomes shallower?

  Water particle orbits become elliptical
• What happens to wave height and wavelength as waves approach the shore?

  Wave height increases, wavelength decreases
• What causes waves to break?

  Water backs up until the wave collapses
• What affects wave energy?

  Strength, duration of wind, size of fetch
• What are constructive waves known for?

  Building up and creating a beach
• What are destructive waves known for?

  Removing the beach and decreasing its size
• What are the characteristics of constructive and destructive waves?

  Constructive Waves:

  • Formed by weather systems in open ocean
  • Long wavelength, 6-9 per minute
  • Low waves, strong swash, weak backwash

  
  

  Destructive Waves:

  • Formed by localized storm events
  • Short wavelength, 11-16 per minute
  • High waves, weak swash, strong backwash
• How do wave types change with seasons?

  Constructive waves dominate in summer
• What can increase storm frequency in coastal areas?

  Climate change
• How do constructive waves affect beach profiles?

  Lead to steeper beach profiles
• What happens when destructive waves occur more frequently?

  They erode the beach
• What is the tidal range?

  Difference in height between tides