Sediment cells Flashcards
What is a sediment cell?
A linked system of sources, transfers and sinks of sediment along a section of coastline
What are the dividing boundaries between sediment cells?
Major headlands or large estuaries
What type of system is a sediment cell and why?
A sediment cell is a closed system as energy is transferred across the system boundary but no matter is transferred
What is dynamic equilibrium in a sediment cell?
Where the inputs and outputs of sediment are in a constant state of change but remain in balance
How can dynamic equilibrium be disrupted?
-Human interventions (long term)
-Natural variations (short term)
What are some ( material or energy) inputs?
-Fluvial sediment from rivers
-Cliff erosion
-Offshore sand banks
-Material from biological origin (e.g. shells and coral fragments)
-Estuaries
-Erosion of depositional features
-Wind
-Precpitation
What are some (material or energy) outputs?
Longshore drift, Sand going offshore, Evaporation, Wave cut platforms, Headlands and bays
What are three examples of sediment/material stores?
Beaches
Sand dunes
Spits
Offshore sediment (bars)
Estuaries
What are some (material and energy) transfers?
Mass movement, Longshore drift, Weathering, Erosion, Transportation, Deposition, Wind-blown, Ocean Currents and Riptides
What are the sources of energy (the power and driving force behind transfer systems) in coastal environement?
Wind, Gravitational force, Flowing water
How many primary sediment cells are there in England and Wales?
11
When will the shoreline extend?
If the inputs exceed the outputs, it will extend and grow as there is a positive sediment budget.
When will the shoreline decline?
When the outputs exceed the inputs, the shoreline will decline and shrink as there is a negative sediment budget.
Are sediment cells fully closed? Use an example to explain this.
No as variations in wind directions and tidal currents may mean that some sediment is transferred between two different cells
