Sediment Cells

Question 1

What is a sediment cell?

Answer 1

A stretch of coastline within which the processes of erosion, transportation and deposition operate and the movement of sediment is largely self-contained.

Question 2

Division of sediment cells

Answer 2

• considered as “closed system”, but in reality small amounts of sediment can move from one cell to another
• larger cells divided into sub-cells
• separated by well-defined boundaries, like headlands and stretches of deep water

Question 3

Sources of sediment

Answer 3

• weathering and mass movement
• rivers and estuaries
• marine organisms (coral, shells etc)
• offshore currents (waves, tides etc)
• longshore currents
• cliff erosion

Question 4

Transport and stores/sinks

Answer 4

• longshore currents redistribute sediment within a cell
• sediment gained from eroding sections of the coastline, called ‘sources’ and lost to sections experiencing deposition called ‘sinks’

Question 5

Sediment budgets

Answer 5

• the balance between inputs (usually from erosion) and outputs (usually from deposition) is called the sediment budget
• where inputs exceed outputs, there is a positive budget and a surplus of sediment
• where outputs exceed inputs there is a negative budget and a deficit of sediment