Coastal systems and landscapes Flashcards
What is the coastal system?
The coast is an open system as it receives inputs from outside the system and transfers outputs away from the coast and into other systems
What is a sediment cell?
Areas along the coastline and in the nearshore area where the movement of materials is largely self contained - they are often boarded by prominent headlands
What are inputs?
Usually referring to material / energy:
-Marine = waves, tides
-Atmosphere = Sun , air pressure, wind speed / direction
-Humans = pollution, recreation, settlements, defences
What are outputs?
Ocean currents
Rip rides
Sediment transfer
Evaporation
Types of stores /sinks?
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
Types of transfers and flows?
Wind blown sands
Mass movement processes
Longshore drift
Weathering
Erosion ( hydraulic action, corrosion, attrition, abrasion)
Transportation ( bedload , in suspension, traction, in solution)
Deposition (gravity settling, flocculations)
Types of energy in the coastal system?
Wind
Gravitational
Flowing water
What are the sediment sources?
Rivers
Cliff erosion
Wind
Glacier
Offshore
LSD
Why are rivers sediment sources?
Account for majority of sediment in coastal zones
Sediment may be deposited in estuaries
Why is cliff erosion a sediment source?
Very important in areas with unconsolidated cliffs that are eroded easily. More erosion occurs during winter months due to more frequent storms
Why is wind a sediment source?
-The wind is a coastal energy source and can cause sand to be blown along or up a beach
-Sediment transport by winds may occur where there are sand dunes which provide sediment inputs
Why are glaciers a sediment source?
Glaciers can flow directly into the ocean depositing sediment that was stored in the ice
Why is offshore a sediment source?
Sediment is transferred to the coastal zone when waves, tides and currents erode offshore sediment sinks. This is transported to the beach
Why is longshore drift a sediment source?
Sediment is moved along the beach, due to prevailing winds which alter the direction of the waves. This allows sediment to be transported from one section of the coastline to another stretch of the coastline
What are sediment budgets?
Use data id inputs, outputs, stores and transfers to access the gains and losses of sediment within a sediment cell
What is the littoral zone?
Area of land between the cliffs or dunes on the coast and the offshore area that is beyond the influence of the waves
What short term factors change the littoral zone?
Tides / storm surges
What long term factors change the. littoral zone ?
Changes in sea level / human intervention
What is the primary source of energy for natural systems?
The sun
What is wave formation?
When the sun has direct influence on the formation of waves, which occur when wind moves across the surface of the water
How is frictional drag created?
When winds move across the surface of the water, this causes small ripples and waves
How is the horizontal movement of waves caused?
As the seabed becomes shallower towards the coastline, the orbit of the water particles beckons more elliptical