1.c. Coastal sediment is supplied from a variety of sources.

Question 1

What is a major source of sediment input to the coastal sediment budget? What is this especially true for?

(Terrestrial)
(Coastal sediment sources)

Answer 1

Rivers.

This is particularly significant for steep gradients.

Question 2

Where may terrestrial sediment delivery originate from?

(Terrestrial)
(Coastal sediment sources)

Answer 2

Floods.

Question 3

What percentage of coastal sediment is from rivers?

(Terrestrial)
(Coastal sediment sources)

Answer 3

80%.

Question 4

Inland sediment sources are often deposited by what?

(Terrestrial)
(Coastal sediment sources)

Answer 4

Water, wind, and ice.

Question 5

What is a large source of sediment, and a major contributor to the sediment budget?

(Terrestrial)
(Coastal sediment sources)

Answer 5

Wave erosion.

Question 6

Erosion of weak cliffs in high-energy wave environments contributes what percentage of overall beach material.

Where is most of this sediment from?

(Terrestrial)
(Coastal sediment sources)

Answer 6

Just under 70% of overall beach material.

This sediment is from large rocks/ boulders, especially from undercut cliffs. Longshore drift also supplies sediment.

Question 7

How do constructive waves supply sediment?

(Offshore)
(Coastal sediment sources)

Answer 7

Bring sediment to the shore from offshore locations and deposit it.

This adds to the sediment budget.

Question 8

Constructive waves bring sediment to the shore. What other marine processes do the same?

(Offshore)
(Coastal sediment sources)

Answer 8

Tides and currents.

Question 9

Wind also blows sediment to the coast. Where may this sediment originate?

(Offshore)
(Coastal sediment sources)

Answer 9

Exposed sand bars, dunes, and beaches elsewhere along the coast.

Question 10

Wind can blow sediment to the coast. What is the carried sediment like? Why?

(Offshore)
(Coastal sediment sources)

Answer 10

Generally fine sand.

This is because wind has less energy than water and so cannot transport very large particles.

Question 11

What process helps to bring sediment equilibrium during a deficit?

(Human)
(Coastal sediment sources)

Answer 11

Beach nourishment.

Question 12

Where is beach nourishment used? How is it done?

(Human)
(Coastal sediment sources)

Answer 12

Nourishment is used globally.

It is inputted by lorries and spread by bulldozers.

Question 13

How is sediment temporarily fixed to the budget?

(Human)
(Coastal sediment sources)

Answer 13

Low banks can hold a mixture of sand and water.

This allows the coastal environment to hold the sediment as the water drains.

Question 14

State 3 processes that remove sediment from the coastal budget?

(Human)
(Coastal sediment sources)

Answer 14

Wind, waves, and longshore drift.

Question 15

How can you find out if a sediment budget is in surplus, deficit, or equilibrium?

(Human)
(Coastal sediment sources)

Answer 15

By subtracting the amount of sediment gained.

Question 16

What is rainbowing?

(Human)
(Coastal sediment sources)

Answer 16

A method of beach nourishment where ships dredge offshore sand and spray it back onshore.

Question 17

Give an advantage of rainbowing.

(Human)
(Coastal sediment sources)

Answer 17

It’s useful for reclaiming areas that are too shallow for direct placement.

Question 18

Give a disadvantage of rainbowing.

(Human)
(Coastal sediment sources)

Answer 18

The very fine sand that is produce from spray nozzles has the potential to asphyxiate local marine life.

Question 19

State and input, store, and throughput of the backshore zone.

(Coastal sediment budget)

Answer 19

Inputs = River sediment.

Stores = Dunes.

Throughputs = Cliff erosion.

Question 20

State and input, store, and throughput of the nearshore zone.

(Coastal sediment budget)

Answer 20

Input = Cliff erosion.

Stores = Beaches.

Throughputs = Longshore drift.

Question 21

State and input, store, and throughput of the offshore zone.

(Coastal sediment budget)

Answer 21

Input = ~.

Stores = Offshore sandbanks.

Throughputs = Offshore transport.