Coastal Systems

Dynamic Equilibrium: This principle suggests that a coastal system aims for a balance where inputs equal outputs. If a change occurs (e.g., a massive storm), the system undergoes negative feedback to restore its original state.

Sediment Budget: The net balance of sediment within a specific coastal area. A positive budget (surplus) leads to beach growth, while a negative budget (deficit) results in shoreline retreat.

Sediment Cells: These are largely self-contained sections of the coast where sediment is recycled. Boundaries are usually defined by major physical features like headlands or deep-water trenches.

Wave Energy Dynamics: Wave energy ($P$) is proportional to the square of the wave height ($H$), expressed as $P \propto H^2$. Small increases in wave height lead to significant increases in erosive power.

High-Energy vs. Low-Energy Coasts: High-energy coasts (e.g., Atlantic-facing) are dominated by erosional landforms like cliffs and stacks, whereas low-energy coasts (e.g., sheltered bays) are dominated by depositional landforms like salt marshes and beaches.

Mechanical vs. Chemical Weathering: Mechanical weathering (like freeze-thaw) physically breaks rock without changing its composition, while chemical weathering (like carbonation) alters the minerals within the rock.

Link Process to Landform: Never describe a landform without identifying the specific processes (e.g., hydraulic action, longshore drift) and wave types that created it.

Use the Systems Language: When discussing coastal change, use terms like 'input', 'output', 'store', and 'transfer' to demonstrate a high-level geographical understanding.

Check the Scale: Distinguish between local factors (like wave refraction at a headland) and regional factors (like the overall sediment cell budget).

Verify Equilibrium: If a question asks about human impact, discuss how it disrupts the dynamic equilibrium and the potential for positive feedback loops (where a change is amplified).