2 - Coasts (Sediment)

Question 1

What are sediment cells?

Answer 1

The distinct areas within which sediment movements occur.
They vary in size and can be divided into sub-cells to allow closer management.

Question 2

What kind of system is a sediment cell?

Answer 2

A balanced system (inputs and outputs are equal)
A closed system - sediment can’t move from one cell to another.

Question 3

What are examples of the boundaries of a sediment cell?

Answer 3

Headlands or stretches of deep water.

Question 4

How many sediment cells have been identified along the coast of England? Name 3.

Answer 4

11!
St Abb’s Head
Flamborough Head
River Thames

Question 5

What are the 5 sources of sediment?

Answer 5

Rivers = most sediment input!
Cliff erosion = more frequent in winter months due to more frequent storms
Wind = blows sand along/up beaches
Glaciers = when glaciers calve (ice breaks off), sediment stored in ice is deposited.
Offshore = waves, tides, currents, storm surges, tsunami waves
Longshore drift = sediment moves along the coastline due to wind and waves.

Question 6

What is a sediment budget?

Answer 6

The difference between the amount of sediment that enters and the amount that leaves the system.

Question 7

Describe a positive sediment budget/surplus of sediment.

Answer 7

More material is added to the cell than is removed = a net accretion of material, shoreline builds toward the sea.

Question 8

Describe a negative sediment budget/deficit of sediment.

Answer 8

More material is removed from the cell than is added = shoreline retreats landward.

Question 9

What are the 4 main sediment sources?

Answer 9

Natural sources:
- cliff and dune erosion
- offshore transport
- river sediment

Human sources:
- beach nourishment

Question 10

What are the 3 main sediment losses?

Answer 10

Natural losses:
- offshore transport
- wind and storm overwash

Human losses:
- dredging and sand mining