Coasts EQ3 Flashcards
Give a place example of an area experiencing rapid coastal erosion in the UK.
The Holderness coastline, the fastest encoding coast in Europe
At what rate is the Holderness coastline eroding?
2m a year on average. Some places eroding at 4m per year
How many homes in Holderness will fall into the sea by 2100?
200 homes
The EA suggests 7000 homes will disappear nationally due to coastal erosion.
What conditions make Holderness vulnerable to wave action?
Deep water of the coast allows for waves to approach at higher speeds.
A large fetch reaching across Atlantic and north sea can be as long as 5000km- providing waves with more energy.
Low pressure system- causes intense winds and high tides
How does the geology of Holderness make it vulnerable to coastal erosion?
The coast is made up of unconsolidated glacial till vulnerable to freeze thaw and alternating cycles of wetting and drying caused crumbly dry periods. Can also cause slumping.
Made of boulder clay- easily eroded
How do the beaches at Holderness influence coastal erosion?
Beaches are main issue, made of clay so easily transported/eroded.
The beaches are narrow= little friction, poorly protecting the cliff from waves. Vulnerable to long shore drift
How has human interference impacted the coastal erosion in Holderness?
Coastal defences placed in Hornsea (North holderness) have disrupted sediment cell equilibrium (terminal ground syndrome)
Give a place example of an area experiencing rapid coastal erosion (not in the UK)?
The Nile Delta
What is the Aswan High Damn what what impact did it have on river discharge?
Built in 1960 The High Dam was built across the Nile in Egypt.
causing river discharge to fall from 35billion cubic metres a year to 10billion.
Describe how erosion rates have changed at Rosetta/ the Nile Delta.
Erosion rates at rosetta have increased from 25m to 200m/year
What was the impact of human activities in Mauritania?
The newly built seaport in Nouakchott blocks strong N-S littoral drift, as a result there is massive accretion at the updrift side and equivalent erosion at the down drift side of the harbour= coastal recession.
Give an example of mass coastal flooding (not in UK).
Bangladesh
What physical factors contribute the coastal floodimg of Bangladesh?
- much of the country is low lying, only 1-3m above sea level.
- Lies on the floodplains of three major rivers ( Ganges, Brahmaptura and Meghna) which all empty to the Bay of Bengal.
- Widespread thunderstorms march- may= high wind speeds (160km), high waves (up to 6m)
- Himalayan snow melt contributes to flooding
What human factors contribute to coastal flooding in Bangladesh?
-Densely populated (46% of population lives less than 10m below sea level)
-Subsistence, the clearance and drainage of over 50 islands on the river delta (deforested for rice farms).
- Mangrove vegitation loss, 25% of mangrove area converted to shrimp farms- reduction in stabilisation against erosion.
Which category 4 cyclone hit Bangladesh in November 2007?
Cyclone Sidir
During Cyclone Sidir to what extent were the wind speeds and height of the storm surges?
Strong winds reached up to 130-160mph and storm surges reached up to 6m in height.
What impact did Cyclone Sidir have on Bangladesh?
- extensive flooding as embankments were breached
- damaged housing and infrastructure: electricity supplies knocked out
- total cost of damage ~US$1.7billion
- contaminated drinking supply and damaged sanitation infrastructure.
How has climate change impacted Bangladesh ad how have locals adapted?
-groundwater drank by locals contaminated via salt water encroachment.
- locals want embankments raised from 14ft to 25ft.
- many have adapted by switching farming, growing salt tolerant rice and shrimp farming.
Give an example of coastal recession in the UK.
Happisburgh, Norwich. South East England.
What are the natural and human causes of erosion in Happisburgh?
Natural:
- soft unconsolidated lithology.
-longshore drift results in depletion of protective beach material.
- weather conditions: strong prevailing wind from North Sea. Heavy rain
Human activities:
-lack of coastal defences due to high cost and managed retreat policy.
- land use changes- construction of infrastructure and agriculture=drainage=increased runoff.
What are the social impacts of coastal recession in Happisburgh?
-loss of property- EA estimates 30 homes lost over last decade.
-displacement of residents
What are the economic impacts of coastal recession in Happisburgh?
What are the environmental impacts of coastal recession in Happisburgh?
