Geography
Coastal Landscapes
The operation of the coast as a system
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The operation of the coast as a system
The Coastal System Concept
- The coast is viewed as a system, which involves inputs, processes, outputs and feedbacks.
- The key components of the system are sources (inputs), transfers (throughputs or processes), stores and sinks (outputs).
- The coastal system is an example of an open system with energy and matter being freely transferred across its boundary.
Energy Inputs
- The primary energy input into the coast system is the sun, driving weathering processes.
- Wind, waves and tides also provide energy input. The strength and direction of these will impact coastal processes and landforms.
- Human actions can also be a source of energy input through activities that modify the coastal environment, such as dredging or deforestation.
Processes Within the Coast System
- Marine processes including waves, tidal action and longshore drift have key impacts upon shaping the coast.
- Sub-aerial processes such as weathering and mass movement also contribute importantly to the coastal system.
- Erosional processes like hydraulic action, abrasion, attrition, and solution play significant roles in coastal changes.
- Depositional processes, including sedimentation and the action of flora and fauna, are essential in the creation of new coastal landforms.
Outputs, Stores and Transfers
- Material transferred into the coast system is stored in features like beaches, salt marshes and sand dunes.
- Outputs could be sediment transported offshore or along the coast through longshore drift.
- Negative feedback processes help to maintain equilibrium within the coastal system, whereas positive feedback processes, such as the increased wave action caused by sea level rise, will accelerate changes to the coast.
Human Interaction with the Coast System
- Humans often disrupt the natural balance of coastal system through activities like construction, agriculture, and tourism.
- Mechanisms to manage human impact include hard engineering strategies like sea walls and groynes, as well as softer approaches such as beach nourishment and managed retreat.
- The impact of climate change and sea level rise on coastal areas can be catastrophic, exacerbating natural processes and threatening human activities and settlements.
Understanding Begins with Observation
- Field studies and technology advances, including remote sensing, are increasing our understanding of the complex interactions that shape and change coasts.
- Modelling, including geographical information systems (GIS), allows us to observe the potential impact of changes to the coastal system and facilitates in formulating strategies to manage these changes.
