Coasts Case Studies

Question 1

Holderness Coast:

Answer 1

• Fastest eroding coastline at 2m per year (UK), some areas up to 10m per year
• Mostly made up of chalk and soft boulder clay, erodes rapidly when saturated
• Eroding also due to fetch, prevailing winds and LSD moving material South
• Narrow beaches due to limited sediment supply from rapid erosion

Question 2

Kiribati First Climate change refugees:

Answer 2

• 1.2cm sea level rise per year
• Have bought land in Fiji and agree with neighboring countries to allow migration, population of just over 120,000
• Water insecurity
• Mangroves have been planted to limit erosion

Question 3

Jakarta, Indonesia:

Answer 3

• Indonesian capital is sinking, 32 million people
• Sea level rise as a result of climate change
• People are illegally draining underground aquifers because they don’t have access to water
• As a result ground is sinking 25cm per year, 2050 its gone
• 32km sea wall has ben built but its not enough

Question 4

New York:

Answer 4

• Tidal flooding has increased by 247% since 2000
• Increased flooding, infrastructure damage, and threats to low-lying areas like Manhattan and Staten Island.
• urbanisation leads Increases runoff, reduces natural barriers, and contributes to habitat loss for marine ecosystems.

Question 5

Nile Delta:

Answer 5

• Agricultural, urban and industrial sectors are extracting groundwater at exponential rate
• Aswan high dam has reduced the amount of sediment reaching the delta up to 98%
• Increasingly also due to natural gas extraction
• Home to around 41% of Egypt population

Question 6

Bangladesh:

Answer 6

• Subsidence over 1.5m over the last 50 years
• Deforestation to grow rice
• About 30 million live on polders
• All have prevented the natural distribution of sediment
• Lies on the floodplain of 3 major rivers
• Himalayan snow melt and monsoon season adds to flood risk

Question 7

Storm Surges, UK (2013 - 2014)

Answer 7

• Storms driven by powerful jet streams bringing depressions across the Atlantic
• 18,000 people evacuated
• 800,000 properties protected by the environment agency flood defences
• 720 properties were flooded
• Estimated cost was £1bn
• In response gov invested £560 million

Question 8

Storm Surge, Hurricane Sandy

Answer 8

• Wind damage up to 100mph
• 286 total deaths
• One of the costliest hurricanes $60 billion
• 346,000 homes damaged
• +18,000 flights cancelled

Question 9

Mappleton, Holderness Coast

Answer 9

• Supplies 25% of UK gas
• Area is starved of material and eroding at excessive rates
• 2 groynes and rock armour helps protect the cliff but makes cliffs further down south worse
• £2 million

Question 10

Cyclone Sidr - Bangladesh

Answer 10

• 223km/hr
• Storm Surge up to 6m
• Breached coastal and low lying areas
• Extensive flooding
• $1.7 bn in damages
• Water contaminated by debris

Question 11

Fairbourne

Answer 11

• Low lying land, sea level rise
• Residents have to be relocated
• At risk for more violent storms
• Will use hold the line then managed retreat

Question 12

Bacton, North Norfolk

Answer 12

• 1.8 million metres cubed of sand has been placed to replenish beach (sandscaping)
• Protects gas terminal and village
• £20 million
• Beach needs to be replaced every 15 - 20 years

Question 13

Borth, Wales : Management Stategies

Answer 13

Hard Engineering
- Rock Groynes, installed to reduce longshore drift
- Breakwaters, Rock structures designed to absorb wave energy
- Rock Armour, Placed along the shore to protect the coastline from wave attack
Soft Engineering
- Beach nourishment, Sand + gravel replenish the beach and increase its size
- Dune Stablisation, planting vegetation to satablise dunes

Question 14

Borth, Wales: Effectiveness of management strategies

Answer 14

Successes
- Economic Benefits, Protects 400 homes and local businesses
- Tourism, enhanced beach attracts visitors
- Environmental protection, maintains wildlife
Challenges
- Cost, high inital and maintenance cost for hard engineering measures
- Sediment disruption, rock groynes interrupt natural sediment transport

Question 15

Happisburgh: Hard engineering approaches

Answer 15

• Sea Wall: Installed to protect key infrastructure but has not been maintained due to cost.
• Groynes: Constructed to trap sediment and reduce longshore drift, but these became ineffective due to lack of sediment supply from neighbouring areas.
• Rock Armour: Large rocks placed at the base of the cliffs to absorb wave energy, though limited in extent.

Question 16

Happisburgh: Successes

Answer 16

Successes

• The hard engineering defences initially slowed down erosion and protected the most vulnerable areas of the village.
• Beach nourishment provided a temporary buffer, reducing wave energy and erosion in the short term.
• The managed retreat approach has been praised for being cost-effective and more sustainable over the long term.

Question 17

Happisburgh: Failures

Answer 17

• Groynes became ineffective due to sediment starvation, leading to increased erosion down-drift.
• Hard defences were costly to maintain and often led to higher erosion in adjacent, unprotected areas.
• Funding cuts resulted in the abandonment of some hard defences, leaving parts of the village vulnerable.
• Beach nourishment required constant replenishment, which was expensive and unsustainable.

Question 18

Sediment transport and the depositional landforms they create

Answer 18

• Spit, A spit is a long narrow strip of land which is formed due to deposition. Longshore
  drift occurs along the coast line.
• Salt marsh, overtime the sheltered area behind a spit can turn into a salt marsh
• Tombolo, A tombolo is a bar or
  beach that connects the mainland to an offshore island and is formed due to wave
  refraction off the coastal island reducing wave velocity
• Bars, A spit which, over time,
  crosses a bay and links up two
  sections of coast

Question 19

Sub-aerial processes - Weathering

Answer 19

• Mechanical weathering is the breakdown of rocks due to exertion of physical forces
  without any chemical changes taking place such as Freeze thaw
• Chemical weathering is the breakdown of rocks due to chemical reactions such as carbonation
• Biological weathering is the breakdown of rocks due to the actions of plants, bacteria and animals

Question 20

Sub-aerial Processes, Mass movement

Answer 20

• The type of mass movement that occurs depends on the angle of the slope/cliff and the vegetation covering cliff face
• Mudflows, an increase in the water content of soil can reduce friction, leading to mud flowing over underlying bedrock
• Rock falls, occur on sloped cliffs when exposed to mechanical weathering
• Rock slides, water between joints and bedding planes can reduce friction, leading to more sliding
• Slumps, occur when the soil is saturated with water, causing a rotation movement of soft materials forming rotational scars

Question 21

Emergent coastlines

Answer 21

• Raised beach, above high tide level usually vegetated by plant succession
• Derelicts caves and stumps

Question 22

Submergent Coastlines

Answer 22

• Rias, a drowned river valley, eroded steep sided v shaped valleys
• Fjords, drowned glacial valleys, relatively straight profile
• Dalamtian coasts, produced by sea level rise flooding the coastlines