The Various Sources Of Coastal Sediment

Question 1

What are the 3 sources of coastal sediment

Answer 1

1. Terrestrial
2. Offshore
3. Human

Question 2

Give an example of a major source of sediment input (terrestrial)

Answer 2

Rivers. Especially with coasts with steep gradients

Question 3

When does most sediment delivery happen? Give a statistic (terrestrial)

Answer 3

During floods. In some places, 90% of coastal sediment comes from rivers

Question 4

How does sediment form? (terrestrial)

Answer 4

Throught the erosion of inland areas with water, wind and ice as well as sub aerial processes like weathering and mass movement

Question 5

Wave erosion (terrestrial)

Answer 5

Also the source of large amounts of sediment and makes major contributiona to coastal sediment budgets

Question 6

Cliff erosion (terrestrial)

Answer 6

It increases due to rising sea levels and is amplified by storm surge events

Question 7

Fact about eeosion of weak cliffs

Answer 7

Contributes up to 70% of material supplied to beaches (some of this sediment is large rocks)

Question 8

Does longshore drift contribute? (terrestrial)

Answer 8

Yes

Question 9

How do contructive waves contribute? (Offshore)

Answer 9

The bring sediment from offshore locations (marine deposition)

Question 10

Define marine deposition (Offshore)

Answer 10

This is when constructive waves, tides or currents bring sediment from offshore locations and deposit it.

Question 11

Wind (Offshore)

Why does it only depodit fine sand?

Answer 11

Also blows sediment from offshore locations including sandbars, dunes and other beaches.

Because wind does not have as much energy as water so it cannot transport large particles

Question 12

Give an example of a way to maintain the sediment equilibrium (human)

Answer 12

Beach nourishment is used globally to protect the coastal environment

Question 13

Give an example of a way that beach nourishment happens (human)

Answer 13

Sediment can be brought via lorries which dump it onto the beach so it can be spread out by bulldozers.

Question 14

Can wind, waves and LSD movements remove sediment from the coastal sediment budget?

Answer 14

Yes

Question 15

Equation for sediment budget (see page 8 just above skill focus)

Answer 15

Sediment budget= amount of sediment gained- amount of sediment lost

Question 16

If inputs are 20 and 80 and outputs are 70, is the sediment budget in surplus or deficit?

Answer 16

(20+80)-70= 30

So its in surplus