Coastal Landforms and Processes Flashcards
Where is the Sundarbans
South India & Bangladesh on the Bay of Bengal, covering the worlds largest delta
How many people live in the Sundarbans?
4 million people
What challenges do people living in the currently Sundarbans face?
Salinisation - sea level rise has lead to more areas becoming affected by salt-water which is more difficult for crops to grow in
Coastal flooding + cyclones - 90% of energy is absorbed by forest but deforestation…
Conversion of wetland to high intensive farmland - people who rely on wetlands for income lose income / RESOURCE CONFLICT
What challenges will people in the Sundarbans face in the future? + responses
Increased freq of floods / NGO’s providing education to locals so they know what to do
Changes to seasonal rainfall / water tanks in area @ risk, NGO’s build important facilities on higher ground
What are some opportunities in the Sundarbans
Eco-tourism
Natural products (crab, fish, honey, wood)
What adaptations that people in the Sundarbans have made?
Higher ground housing - stilts
Ducks instead of chickens - which can swim
What 3 rivers major flow through the Sundarbans?
Gnges, Brahmaputra, & Meghna
Where is the Holderness Coast?
East coast of England
What shoreline management plan is in place on the Holderness Coast?
Majority of the coastline is ‘No active intervention’ with 4 areas having a ‘Hold the line’
Which areas on the Holderness coast have the ‘Hold the line’ in place?
Mappleton, Bridlington, Hornsea, and Withernsea (B+H+W all have 6000+ population)
Why does Mappleton qualify for Hold the Line intervention? + what did it receive
The village has a main coastal road linking the 3 main towns in the area together
In 1991, a £3.5 million coastal defence was put in place - granite groynes, rock armour, & seeding of cliff surfaces
What did the 3 coastal town receive?
Bridlington, Hornsea, and Withernsea all received hard engineering measures including a concrete sea wall and groynes
Why is there protection around Easington
Easington has a major gas terminal for gas coming in from the Northern Sea. It accounts for 20% of UK gas imports
Protected by rip-rap, gabions, and concrete blocks
How fast does the Holderness coastline erode?
Up to 2m a year - the fastest eroding coast in Europe
Example of negative feedback
Erosion at bottom of cliff
Mass movement creates a barrier at base of cliff
Cliff base is protected from further erosion for a period
How does a spit form?
A spit forms when LSD causes the beach to extend out towards the sea. This is usually due to a change in the direction of the coastline. Wind direction is a major factor
How does a salt marsh form?
A salt marsh forms behind a spit due to the sheltered, saline environment where the speed of water flow is significantly reduced. This allows for the deposition of finer sediment to be deposited.
How does a barrier beach form?
A barrier beach forms when a spit extends across 2 headlands.
How does a tombolo form?
A tombolo is formed by a spit extending out and joining the mainland with an island.
How does an offshore bar form?
An offshore bar is formed when the waves carrying the sediment do not have enough energy to carry the sediment to shore so is deposited. A destructive wave could get sediment from the beach, and then deposits it offshore.
How does a sand dune form?
- Dry sand accumulates around an object (rock, branch etc)
- As more sand accumulates, the dune grows and vegetation may grow on the surface. The roots may stabilise the dune (marram grass)
- Sand develops into soil, with lots of moisture and nutrients available from the short-lived plants.
- As the water rises towards the sand dune, water will become trapped in the sand. This promotes growth of more plants
- As the sand dune develops it will become larger and will be able to support larger plants.
How does a mudflat form?
A mudflat is formed by a positive feedback loop.
1. Initial deposition of fine silt
2. Submerged and semi-submerged plants grow in the silt
3. The plants trap more silt/sediment + reduce water velocity so more deposition occurs
4. Plants decay & add to the sediment
5. Gradual increase in height
6. As height increases, saline conditions decrease
How does a ria form?
Flooded river valley - sea level rise
How does a fjord form?
Flood glacial valley - sea level rise
What is a dalmation coastline?
A flooded valley parallel to the coast creating a series of elongated islands offshore
What is isostatic change?
Isostatic change occurs when land rises or falls relative to the sea. It is a local change
For example, during the last glacial period, the UK sunk into the mantle. After the ice melted/retreated the UK has gradually risen
What is eustatic change?
Eustatic change affects the sea level globally. (eustatic = everywhere) It can be caused by thermal expansion / contraction
How many people are at risk from coastal flooding?
410 million at risk (1 billion people live in a “coastal area”)
