coasts case studies Flashcards
holderness
about
61km long, from flamborough head to spurn head
most of the cliffs are made of till (boulder clay) and the coast is exposed to powerful destructive waves from the north sea during storms
east yorkshire
holderness
coastal processes
erosion
the soft boulder clay is eroded easily by wave action
in some places, e.g. great cowden the rate of erosion has been over 10m per year
holderness
coastal processes
mass movement
boulder clay is prone to slumping when its wet
water makes the clay heavier and acts as a lubricant between particles which make it unstable
holderness
coastal processes
transportation
prevailing winds from the northeast transport material southwards
these winds also create an ocean current which transports material south by longshore drift
rapid erosion means there is always plenty of sediment to be transported
holderness
coastal processes
deposition
where the ocean current meets the outflow of the humber river, the flow becomes turbulent and sediment is deposited
holderness
landscapes
headlands and wavecut platforms
to the north of the area the boulder clay overlies chalk, the chalk is harder and less easily eroded so it has formed a headland: flamborough head and wave cut platformss, such as those near sewerby
flamborough head has features such as stacks, caves and arches
holderness
landscapes
beaches
the area to the south of flamborough head is sheltered from wind and waves, and a wide sand and pebble beach has formed near bridlington
holderness
landscapes
slumping cliffs
frequent slumps give the boulder clay cliffs a distinctive shape
in some locations several slumps have occurred and not yet been eroded, making the cliff tiered
e.g. slumps around atwick sands
holderness
landscapes
sand dunes
around spurn head, material transported by the wind is deposited, forming sand dunes
holderness
landscapes
spit
erosion and longshore drift have created a spit with a recurved end across the mouth of the humber estuary: spurn head
to the landward side of the spit, estuarine mudflats and saltmarshes have formed
holderness
hard engineering
11.4km of 61km protected by hard engineering
bridlington: 4.7km sea wall and timber groynes
hornsea: sea wall, timber groynes and riprap
skipsea: gabions
withernsea: groynes and sea wall
easington gas terminal protected by revetment
holderness
existing schemes
not sustainable
1) groynes protect local area but increases erosion of cliffs down drift
2) reduction in sediment due to groynes increase the risk of flooding and increases erosion
3) the protection of local areas is leading to the formation of bays between those areas. as bays develop the wave pressure on headlands will increase and eventually the cost of maintaining the sea defences may become too high
holderness
challenges for schemes
current smp is hold the line at some settlements and do nothing at less populated areas however this is unpopular with residents
managed realignment more sustainable but compensation would be an issue and land isnt always available
1995: do nothing for spurn head which saves money and allows the spit to function naturally but overwashing may damage marsh environments and a coastguard station may be at risk
the sundarbans
about
southwest bangladesh and east india
on the delta of the ganges, brahmaputra and meghna rivers on the bay of bengal
large parts are protected as a national park
part of the largest mangrove forest in the world
land is very flat and low lying
it is intersected by thousands of channels, many containing small sandy or silty islands
home to many rare species
in its natural state the coastal system is in dynamic equilibrium, material is deposited by rivers, allowing the growth of the mangrove forests
it is also eroded by the sea so the size of the sediment store remains roughly the same
the sundarbans
opportunities
products
flat, fertile land of the river deltas is ideal for growing crops, particularly rice
rich ecosystem of the mangrove forest provides the local population with fish, crabs, honey and nipa palm leaves used for roofing and basket making
mangrove forests provide timber for construction, firewood and furniture
the sundarbans
opportunities
services
natural defence against flooding, acts as a barrier against rough seas and absorbs excess water in the monsoon season. this makes it easier to live and grow crops
the mangroves also protect the area against coastal erosion, their roots bind the soil together
the sundarbans
opportunities
development
tourism: people attracted by the mangroves and wildlife
since 2011, cargo ships transporting goods such as oil and food have been allowed to use the waterways, some channels have been dredged to make passage easier for the ships
a power plant has been proposed north of the national park, providing energy for people in the region
the sundarbans
risks
1) lack of fresh water for drinking and irrigation because freshwater is diverted from rivers for irrigation of agricultural land further upstream
2) the growing population has led to the need for more fuel and more agricultural land so the mangrove forests are being removed. this increases risk of flooding and coastal erosion
3) flooding can lead to salinisation of soil, making it hard to grow crops
4) home to dangerous animals that attack humans, e.g. sharks and crocodiles
5) lack of employment and income opportunities
6) low lying land is at risk from rising sea levels due to global warming
7) relatively poor region, 1 fifth of households have access to electricity which makes communication difficult, meaning residents often dont receive flood warnings
8) access is difficult, few roads and those that exist are poor quality which limits opportunities for development and makes it harder for residents to receive goods, healthcare and education.
the sundarbans
attempts to overcome risks
resilience
being able to cope with the challenges the environment presents
attempts to increase the populations resilience:
increasing access to clean water and sanitation to improve health and quality of life
better roads and bridges being built improving access for residents and visitors, however this can lead to deforestation
mains electricity being extended to more areas and subsidised solar panels are being made available in remote villages to allow them to generate their own power, this will make it easier for flood warnings to reach communities and could create employment opportunities
efforts to decrease poverty and increase food security in the region e.g. providing farming subsidies, however some areas may be farmed too intensively, causing environmental damage
some ngos are offering training in sustainable methods of fishing and farming to help prevent environmental damage from over exploitation of poor practices
the sundarbans
attempts to overcome risks
mitigation
reducing the severity of hazards or other problems
3500km of embankments built to prevent flooding however they are gradually being eroded and 800km vulnerable to being breached
coastal management to protect mangrove forests and replant areas that have been removed to protect against flooding and erosion however difficult to prevent illegal forest clearance and unclear whether the mangroves with withstand sea level rise
attempts to mitigate impacts of extreme events e.g. cyclones e.g. governments and ngos have provided funding for cyclone shelters and early warning systems which should help people shelter or evacuate
however many people may not have transport available to enable them to evacuate quickly
the sundarbans
attempts to overcome risks
adaption
adjusting behaviour to fit the environment
as the environment of the sundarbans changes due to climate change and sea level rise people need to adapt to it to reduce risks and increase benefits
e.g.
salt resistant varieties of rice being grown, help residents cope with flooding and sea level rise however relying on a smaller range of crops can reduce biodiversity and may increase vulnerability to pests and diseases
projects to increase tourism providing jobs and income but could cause environmental damage
building houses on stilts however infrastructure such as roads not protected as easily
sustainable adaptions e.g. non intensive farming practices and promoting ecotourism will help ensure that fragile environment remains relatively undamaged and usuable for future generations
