Main question

How does the coast act as a system?

Questions

Copy the table in Resource A and label the terms in the correct columns (some terms may be used more than once).

Define the meaning of dynamic equilibrium in the context of a coastal system.

Suggest which of the situations outlined in Resource B are examples of positive feedback and which are examples of negative feedback.
Explain your choices in question 3a).

Resource A

Erosion, Cliff, Transport, Sediment Deposition, Weathering,
Beach, Energy, Estuary, Mass movement

Inputs	Outputs	Processes and Transfers	Stores and sub-systems

Resource B
- 1. In a storm destructive waves will erode the beach. The eroded sediment will be deposited as an offshore bar. Waves lose energy when traveling over the bar, therefore erosion will slow down. When the storm stops, constructive waves move the sand from the bar back to the beach.
- 2. Part of a sand dune was eroded in a storm. As a result there will be an area of the dunes bare of vegetation. Wind will be able to erode more of the sand here, making the breach larger. Waves can then erode more of the dunes.
- 3. Vegetation grows in a salt marsh in a river estuary. The vegetation slows the flow of water, therefore more sediment will be deposited. This raises the level of the marsh, allowing more vegetation to grow. This in turn further slows water flow and leads to even more deposition.
- 4. Constructive waves will deposit sediment on the beach and make it steeper. This leads to deeper water and destructive waves will erode more, removing sediment down the beach and making it less steep again.
- 5. A cliff is undercut by wave erosion and material collapses onto the beach. The collapsed material will absorb wave energy, protect the cliff remains and reduce erosion.
- 6. Sediment is deposited in a river estuary. This will reduce the depth of water and increase friction. This slows down water flow leading to even more deposition.