The operation of the coast as a system, focusing on inputs, outputs, stores, and transfers of energy and materials, sediment cells, and dynamic equilibrium
Topic Synopsis
The operation of the coast as a system, focusing on inputs, outputs, stores, and transfers of energy and materials, sediment cells, and dynamic equilibrium.
Key Concepts & Core Principles
- Inputs: Energy from waves, tides, and currents; sediment from rivers, cliff erosion, and offshore sources.
- Stores: Beaches, dunes, spits, and offshore bars where sediment is temporarily held.
- Flows/Transfers: Longshore drift, tidal currents, and wave refraction that move sediment along the coast.
- Outputs: Sediment lost offshore (e.g., to deep water) or removed by human activities (e.g., dredging).
- Sediment cell: A largely self-contained coastal cell where sediment is input, transferred, and output, with limited exchange between adjacent cells.
Exam Tips & Revision Strategies
- Use the systems framework (inputs, outputs, stores, transfers) to structure answers regarding coastal change.
- Ensure examples of sediment cells are used to illustrate the concept of closed systems.
- Be prepared to apply the concept of dynamic equilibrium to explain how coastlines respond to changing conditions.
Common Misconceptions & Mistakes to Avoid
- Confusing sediment cells with open systems (they are generally considered closed systems).
- Failing to explicitly link energy and material flows to the concept of a system.
- Inaccurate definition of dynamic equilibrium in a coastal context.
Examiner Marking Points
- Identification of coastal system components: inputs, outputs, stores, and transfers.
- Explanation of terrestrial and offshore sediment supplies.
- Understanding of coastal sediment cells as closed systems.
- Explanation of dynamic equilibrium and zones of rapid change within the coastal system.