Coasts

Question 1

When was the Aswan dam built?

Answer 1

the 1960s

Question 2

How much did river discharge fall after the Aswan dam was built?

Answer 2

35 billion cubic m/year to 10 billion cubic m/year

Question 3

What happened to the sediment output when the Aswan dam was built?

Answer 3

Went from 130 million tonnes to 15 million tonnes

Question 4

what happened to the erosion rate when the Aswan dam was built?

Answer 4

went from 20-25 m/year to 200 m/year

Question 5

Give an example of a place where dredging took place

Answer 5

Hallsands in the 1890s

Question 6

How much sediment was removed a day from Hallsands?

Answer 6

1500 tonnes

Question 7

What happened to the beach level at Hallsands?

Answer 7

Began to fall due to the dredging

Question 8

What effect did dredging have on the Hallsands by 1900?

Answer 8

The village was under serious threat from coastal erosion because there was no longer a beach to protect it.

Question 9

What happened in 1917 at Hallsands?

Answer 9

A storm breached the coastal defences causing massive damage.

Question 10

What is Hallsands like now?

Answer 10

It has been completely abandoned

Question 11

Give an example of somewhere at risk of sea level rise

Answer 11

The Maldives

Question 12

What is the population of the Maldives?

Answer 12

400,000

Question 13

What is the highest elevation in the Maldives?

Answer 13

2.3 m

Question 14

How much of the Maldives will be lost if sea levels rise by 0.5m?

Answer 14

77% of the land area

Question 15

What is the average annual erosion rate at Holderness?

Answer 15

2 m/year

Question 16

What is Holderness geology made up of?

Answer 16

Boulder clay left behind after a glacial retreat

Question 17

How long is the fetch along Holderness?

Answer 17

500-800 km to the north sea

Question 18

Why is erosion such a problem for Holderness? (waves)

Answer 18

Ocean currents move north around the UK from the atlantic to the north sea, depression weather systems cause frequent storms, and sea floor is deep in the north sea reducing energy lost by waves

Question 19

why is erosion such a problem for holderness? (geology)

Answer 19

boulder clay erodes easily and produces fine sediment which get lost out to sea

Question 20

where have sea defences been built at holderness?

Answer 20

At Withernsea, Bridlington, Mappleton and Hornsea. This is because cost benefit analysis showed that these areas had assets worth defending.

Question 21

where have defences not been built at holderness?

Answer 21

At Kilnsea the council did not fund sea defences due to a lack of assets worth protecting.

Question 22

What sea defences were built at Mappleton?

Answer 22

6000 tonnes of granite rock armour and 2 large groynes.

Question 23

What was the name of the tropical cyclone that hit Bangladesh in 2007?

Answer 23

Storm sidr

Question 24

What were the characteristics of storm sidr?

Answer 24

Storm surges 6m high and gales reaching 200 kph

Question 25

impacts of storm sidr?

Answer 25

3500 deaths due to drowning, sea water intrusion, and destruction of homes and infastructure

Question 26

What % of Bangladesh is currently protected by embankements?

Answer 26

60%

Question 27

Why is Bangladesh's coastal management approach shifting from hard to soft engineering?

Answer 27

Hard engineering is expensive and may not be as effective in the long term.

Question 28

What are two ways Bangladesh is using soft engineering to reduce coastal recession?

Answer 28

Growing of artificial oyster reefs and mangrove planting.

Question 29

How do oyster reefs mitigate coastal recession?

Answer 29

once established they can grow to hundreds of metres, they promote sedimentation. This stabilises the land and allows vegetation to flourish.

Question 30

How much do mangroves reduce wave velocity?

Answer 30

29-92%

Question 31

According to the world bank if mangroves were lost how many more people would be affected by flooding a year?

Answer 31

18 million

Question 32

Why are mangrove planting and oyster reefs beneficial?

Answer 32

they offer ecosystem services such as providing food sources, marine habitats, and improving water quality.

Question 33

how do Bangladesh's soft engineering schemes help locals? (economically)

Answer 33

There is a higher abundance of fish, shrimp, and crabs near the oyster reefs.

Question 34

How do mangrove forests play a role in climate mitigation?

Answer 34

They store significantly more carbon than terrestrial forrests.

Question 35

Why are eco-engineering strategies sustainable and cost-effective?

Answer 35

They don't require costly repairs, they're self-maintaining, and they can trap sediment to keep up with sea level rise.