Coastal case studies Flashcards
Give the location of a bar?
Start Bay in Devon, with Slapton Ley lagoon behind it
Give some examples of tombolos:
- St Ninian’s tombolo on the Shetland Islands
- The tombolo connection Portland Bill to the mainland in Doreset
Where is an example of a raised beach?
Isle of Arran, Scotland
Where is an example of a relict cliff?
Ayrshire, Scotland
Where is an example of a ria?
Kingsbridge, Devon
Where is an example of a fjard?
Isle of Islay, Scotland
Where is an example of a fjord?
Hardanger, Norway
How long is the Uk’s coastline?
31,368km
Describe the Wash Sediment cell
- The main source of sediment is from cliff erosion at West Runton & Weybourne to the East of the Wash.
- Some sediment comes from tidal currents which pick up glacial deposits on the shallow sea floor
- The soft Holderness cliffs to the North are eroded and carried south in suspension
- Sand is carried South along the Lincolnshire coast
- 4 rivers discharge into the Wash
Where was Holbeck Hall?
Scarborough, in North Yorkshire
What type of mass movement occured at Holbeck Hall?
- The landslide was a rotational landslide degrading to a mud / debris flow which covered the beach
What were the anticedent conditions at Holbeck Hall?
- There had been 140mm of rain in the 2 months before the slide, leading to saturated conditions
Describe Bangladesh and its islands:
- Estimated population of 169 million in 2015
- Eighth most populated country in the world
- 46% of the country’s population lives on land less than 10 meters above sea level
Describe Bangladesh’s physical causes of coastal flooding:
- Bangladesh lies on the floodplains of three major rivers- the Brahmaputra, Ganges and Meghna, which all converge in Bangladesh
- There are also 54 smaller rivers that flow into the Bay of Bengal through a series of estuaries
- Almost every year huge areas of the country flood as Himalayan snow melt adds to monsoon rains and high tides in the Bay of Bengal
- Between March and May violent thunderstorms produce strong winds which bring 6 metre high waves from the Bay of Bengal to swamp coastal areas
Describe Bangladesh’s human causes of coastal flooding:
- Deforestation may be partly to blame, causing soil erosion which reduces the ability of the land to absorb water
- Irrigation for farming is a factor, because this causes river channels to silt up, reducing their capacity to hold flood waters
- Climate experts also believe global warming is partly to blame, by increasing monsoon rainfall and speeding up the melting of Himalayan snows
Describe the subsidence of Bangladesh’s islands:
- Some of Bangladesh’s estuarine islands have sunk by as much as 1.5m in the last 50 years.
- Isostatic readjustment is partly responsible, but the main reason is the clearance and drainage of more than 50 large islands in the Ganges-Brahamputra river delta
Describe the history of Bangladesh’s islands:
- They used to be forested , but now have been cleared and are being used to grow rice to feed the country’s large population
- In the 60s and 70s, large earth embankments were built around these islands to protect them against tidal and storm surges
What defenses has Bangladesh introduced for their islands?
- Over the last 50 years, Bangladesh has built 4000km of embankments along the coast
- About 30 million people live on polders (land enclosed by the embankments).
- In 2014, Bangladesh was planning to spend $400 million from the World Bank to upgrade the embankments
How have human actions impacted Bangladesh’s islands?
- They’ve prevented the natural deposition of sediment that used to maintain the island’s height.
- Now these islands are fast submerging and millions of people living on them are at increased risk of flooding if the embankments give way.
What made Sri Lanka take better care of its mangrove forests?
- In a report published after the 2004 Indian Ocean tsunami, it compared two coastal villages hit by the wave.
- It showed that two people died in the settlement protected by dense mangrove and scrub forest, while up to 6000 people died in the village that had removed the protective vegetation
What did Sri Lanka do to their mangroves?
- They became the first nation in the world to protect all of its mangrove forest
- Its scheme will protect all 8800 hectares of remaining forest, as well as replanting magroves that have already been felled
- By providing micro-loans for villages in exchange for them protecting local mangrove forests
What are the advantages of conserving mangrove forests?
- They store huge amounts of carbon in the top layers of the soil
- In a healthy mangrove ecosystem, the stilted root systems serve as nurseries for many of the fish species that go on to populate coral reefs.
Describe the location of mangrove forests:
- Mangrove forests are found along the tropical and sub-tropical areas of Africa, Australia, Asia and the Americas
- The largest remaining area of mangrove is found in the Sundarbans region of Bangladesh, on the edge of the Bay of bengal
Why are mangroves so important?
- They are an essential and complex ecosystems for both marine and freshwater biodiversity
- They stabilise coastlines against erosion and provide a nursery for coastal fish
- They also provide shelter against extreme weather events such as storm winds and floods, as well as tsunamis,
- They absorb and disperse tidal surges associated with these events
Describe mangroves in Bangladesh:
- Mangroves helped to protect the area from coastal flooding in Nov 2007 during Cyclone Sidr
- Since then, satellite studies show that 71% of the forested coastline has retreated by 200m/year
- The causes of this are rising sea levels, erosion and deforestation from humans
- 25% of the mangroves lost have been converted into areas for shrimp farms which has been good for the local economy
When and where did a storm surge impact the UK?
- 5th December 2013
- A large storm surge hit the east coast of the UK
Why did the 2013 storm surge occur?
- Low pressure, igh winds and high tidal conditions combining
- The storms were driven by powerful jet streams bringing depressions across the Atlantic
Describe preparation and warnings for the 2013 storm surge:
160,000 warnings sent out to homes and businesses
18,000 people evacuated
800,000 properties protected by the Environment Agency flood defences
London saw the highest tide since the Thames barrier was built in 1984
2,800km of flood defences were put to the test along the coast
64 severe flood warnings were in place at its peak
Describe the impacts of the 2013 UK storm surge:
720 properties were flooded
1,700 hectares of farmland were flooded
The estimated cost for the government was £200 million
How did coastal flooding occur in Bangladesh, and when?
Cyclone Sidr in the Bay of Bengal
15th November 2007
Describe Cyclone Sidr:
- Brought with it storm surges of 6 metres.
- Heavy rain and 223km/hr winds
- It was a Category 4 storm
Describe the impact of Cyclone Sidr:
- The storm surge breached coastal and river embankments, causing extensive flooding of low-lying areas
- High winds damaged housing, roads, bridges and other infrastructure
- Electricity supplies and communications were knocked out and roads and waterways became impassable
- Drinking water was contaminated by debris, and many wells were flooded with salt water
- The sanitation infrastructure was destroyed raising the risk of disease
What was the estimated cost of Cyclone Sidr?
US$1.7 billion
What flooding event occurred in the Netherlands, and where?
2013 storm surge
Describe the Netherlands 2013 storm surge:
- Strong winds together with a storm surge that was predicted up to 2 metres high in the Netherlands
Describe and explain the impacts of the 2013 Netherland storm surge:
- No one died
- This is because the Netherlands constructed a series of Delta Works in response to a 1953 storm surge, where there were casualties
What is Delta Works in the Netherlands?
- Consists of a series of dams and storm surge barriers, designated to protect the country from flooding by the North Sea
- It cost 2.5 billion Euros to build and a further 1.7 billion euros a year to operate
- it was opened in 1986
Describe the Maldives:
- Comprised of nearly 1,200 islands are coral atolls in the Indian Ocean
- The Maldives are only 81.5 metres above sea level at its highest point
Explain the economy in the Maldives:
- Tourism accounts for 28% of the total GDP.
- 90% of the government’s import taxes come from imported goods for tourism.
- Farming is not possible as the islands are so low-lying
When will the Maldives become uninhabitable?
The IPCC have estimated that at current rates of sea-level rise, the Maldives will be uninhabitable by 2100
What are the social impacts of coastal flooding in the Maldives?
- Future displacement of population and communities split
- Destruction of houses from increased erosion
- Death of coral will result in less biodiversity which will impact fishermen
What are the economic impacts of coastal flooding in the Maldives?
- Flooding could destroy resorts and beaches, resulting in the loss of the $2billion tourist industry
- If the airport is lost then the population will be cut off from the rest of the world and there will be no money to be made from tourists.
What are the environmental impacts of coastal flooding?
- Beaches suffer from increased erosion and sediment removal
- Coastal flooding can contaminate groundwater with salt.
What is found at the Nile Delta?
Holiday beach resorts
Coastal defences
General tourism
Marine recreation
Fisheries
Land reclamation
Agriculture
Settlements
Transport and port infrastructure
Describe the Nile Delta:
- Has a 240-km coast in the eastern Mediterranean
- The delta area is where 95% of Egypt’s population live
- The coastline is experiencing retreat
- There is salt intrusion into the delta due to sea-level rise and coastal flooding is becoming more frequent
What is the Nile Delta?
A depositional landform formed from sediment brought down the Nile by annual floods
When was the Aswan dam built and what effect did this have?
- Built in the 1960s
- River discharge fell from about 35 billion m³ per year to around 10 billion m³.
- More significantly, sediment volume fell from 130 million tonnes to about 15 million tonnes
Why did the Aswan dam result in drops in river discharge and sediment volume from the Nile delta?
- Water withdrawals for industry, cities and farming from the reservoir behind the Aswan dam
- Water in the reservoir flows very slowly allowing sediment to be deposited
Are the Aswan dam effects an isolated case?
The construction of the Akosombo Dam in Ghana in 1965 also reduced the flow of sediment down the river
Why is the Nile Delta important?
It is an intensive farming area and also attracts numerous tourists to its beach resorts and to the river’s many tributaries.
A number of ports- vital for imports and exports to Egypt- are also situated along the Delta coastline
How has the Aswan Dam affected farming?
It has limited the natural seasonal flooding of the Delta
This flooding was responsible for depositing rich, fertile sediments- perfect for farming- on the river banks.
What other changes in the Nile Delta are affecting farming?
Increasing sea levels are increasing the salinity of the Delta, decreasing it’s fertility and thus affecting livelihoods
How much of Egypt’s food supply relies on the Nile Delta?
60%
