The operation of the coast as a system
The Coast as a System
Systems Concept
- The system in geography is used to understand and organise complex interactions and interrelationships.
- A coastal system is an open system with inputs, processes, outputs and feedback within a distinct boundary, often defined by a watershed.
Inputs, Processes, Outputs
- Inputs into the coastal system include energy from waves, wind, tides, and ocean currents, sediments from rivers, cliffs, and onshore/offshore transport, and human impact.
- Processes within the system can be divided into transport processes (longshore drift, traction, saltation, etc.) and erosional or depositional processes (hydraulic action, abrasion, attrition, solution, etc.).
- Outputs from the system consist primarily of sediment transported offshore or along the coast, changes in coastal morphology due to erosion and deposition, and altered ecosystems.
Feedback Mechanisms
- A feedback mechanism in coastal systems can be positive or negative, enhancing or constraining changes in the system.
- Positive feedback amplifies system changes - for example, coastal erosion increases as beach material is removed, allowing waves to attack the base of cliffs more easily.
- Negative feedback counteracts system changes - for example, a build-up of sediment in coastal waters can reduce wave speed and energy, limiting further erosion or deposition.
Sediment Cell Concept
- A sediment cell, or littoral cell, is a management tool used to trace the movement of sediments within a particular section of coastline.
- Sediment cells often have clearly defined boundaries, such as headlands, where the input and output of material roughly equal.
Human Influence
- Human activity introduces another variable, affecting every aspect of the coastal system, from inputs (adding or subtracting beach material), through processes (construction of sea defences), to outputs (changes in coastal development strategy).
- Understanding the role of humans in coastal systems is crucial in managing for the future, to minimise risks and maximise opportunities.
Case Studies for Coastal Landscapes
- Identify specific real-world examples that illustrate these points (e.g., Holderness Coast, UK; Chesapeake Bay, USA). Understand not only the physical aspects of the chosen coastlands, but also socio-economic factors.
- Use your chosen case studies to deepen your understanding of concepts, and to reinforce the mechanisms within the coastal system.