Processes of coastal transport and deposition and the characteristics and formation of associated landforms and landscapes — Eduqas A-Level Geography

Coastal transport and deposition are fundamental processes that shape the world's coastlines, creating a diverse array of landforms such as beaches, spits, and bars. Transport involves the movement of sediment along the coast by waves, tides, and currents, primarily through longshore drift. Deposition occurs when wave energy decreases, causing sediment to be dropped. Understanding these processes is crucial for predicting coastal change and managing erosion and flooding risks.

This topic explores how sediment is transported via traction, saltation, suspension, and solution, and how deposition builds features like beaches, sand dunes, and salt marshes. It also covers the formation of distinctive landforms such as spits, tombolos, and barrier islands, which are shaped by the interplay of sediment supply, wave energy, and sea-level change. These landforms are dynamic and respond to both natural processes and human intervention.

In the WJEC A-Level Geography course, this topic connects to broader themes of coastal systems, sea-level change, and coastal management. It requires students to apply knowledge of geomorphological processes to real-world examples, such as the Holderness Coast or the Mississippi Delta. Mastery of this content is essential for understanding how coastlines evolve over different timescales and for evaluating management strategies.

• →Longshore drift: The zigzag movement of sediment along the beach due to waves approaching at an angle, driven by prevailing wind direction.
• →Sediment cell: A closed system of sediment transport, erosion, and deposition, with inputs (e.g., cliff erosion) and outputs (e.g., offshore losses).
• →Depositional landforms: Features like spits (extending across a bay), tombolos (connecting an island to the mainland), and barrier beaches (offshore ridges) formed by sediment accumulation.
• →Swash and backwash: The uprush (swash) and downrush (backwash) of waves; deposition occurs when swash is stronger than backwash, often on constructive waves.
• →Sediment sorting: The process by which waves sort sediment by size, with coarser material deposited on the upper beach and finer material lower down.

• Processes of coastal transport: solution, suspension, saltation, traction, and longshore drift
• Processes of coastal deposition: reduced energy levels, flocculation, and sediment sorting
• Characteristics and formation of coastal landforms: beaches, spits, bars, tombolos, and cuspate forelands

• 💡Use clear, annotated diagrams to illustrate the formation of landforms like spits and bars
• 💡Ensure you can explain the role of longshore drift in the development of depositional landforms
• 💡Be prepared to provide examples of these landforms from both UK and non-UK contexts
• 💡Use precise terminology for transport processes (e.g., solution, suspension, saltation, traction)
• 💡Use annotated diagrams to show the formation of landforms like spits and tombolos. Label key processes (e.g., longshore drift, deposition) and features (e.g., recurved end, salt marsh).
• 💡Link processes to specific case studies. For example, explain how longshore drift forms Spurn Head (Holderness) or how sediment supply from the Mississippi River builds the delta.
• 💡Discuss timescales: Distinguish between short-term (e.g., storm beach ridges) and long-term (e.g., barrier island migration) changes, and reference sea-level rise or human intervention.

• Confusing the specific mechanisms of transport (e.g., saltation vs. traction)
• Failing to link the reduction in energy levels directly to the process of deposition
• Inaccurate description of the formation sequence for complex landforms like spits or tombolos
• Neglecting to mention sediment sorting as a key outcome of depositional processes
• Misconception: Longshore drift only moves sediment in one direction. Correction: It moves sediment in the direction of the prevailing wind and waves, but this can change seasonally or with storm events.
• Misconception: Spits form only where there is a river mouth. Correction: While river mouths can provide sediment, spits can form anywhere there is a change in coastline orientation and sufficient sediment supply.
• Misconception: Deposition only happens in calm conditions. Correction: Deposition can occur during storms if sediment supply is high and wave energy dissipates quickly, such as in the lee of a headland.