Human Actions & Coastal Recession

Question 1

Rapid coastal recession is caused by physical factors (geological and marine) but can also be influenced by human actions such as

Answer 1

dredging, dams or coastal management

These actions affect the processes within the coastal system including those in the sediment cell

Question 2

Dredging

Answer 2

The removal of sediment from rivers or the sea

This impacts on the amount of sediment being deposited at the coast

Question 3

Dams
The construction of dams, traps ………….. behind the dam wall

It is estimated ……………..billion tonnes of sediment is stored behind the world’s dams and this increases by a billion tonnes each year

Like dredging, this starves the coast of sediment

Answer 3

river sediment

100

Question 4

It is estimated that dams on the river Ebro in Spain have led to a ………% reduction in sediment downstream

Answer 4

93%

Question 5

The reduction of sediment supplied to the coast due to dams and dredging leads to greater coastal erosion because:

Answer 5

Beaches decrease in size as they are not being supplied with sediment

Destructive waves have more impact by increasing the rate of coastal erosion

Question 6

Coastal management

Coastal management can impact on the rate of recession because it affects the rate of erosion

In some areas coastal defences such as in places like Hornsea sea walls and rip rap reduce the amount of erosion

This slows recession of the coast

Question 7

In other areas coastal management affects the movement of sediment
Groynes at Hornsea on the Holderness coast reduce

Answer 7

longshore drift

Question 8

Groynes at Hornsea on the Holderness coast reduce longshore drift which has a affect on where

Answer 8

This starves areas down the coast such as Mappleton of sediment also known as terminal groyne syndrome

Question 9

As with dams and dredging the reduced supply of sediment decreases………….. and increases….

Answer 9

beach size and increases the impact of destructive waves