Case Studies Flashcards
Physical causes of bostcastle flood?
Much of the drainage basin rock is impermeable.
High tide at sea.
Valency river has a small catchment area 23km2 with a steep gradient.
Torrential rain over 500mm in 4 hours.- remnants of hurricane Alex. Due to rainy summer, by August the sandstone was saturated.
Social impacts of flooding boscastle flood?
Destroyed homes
Stress and anxiety for local people.
No casualties or serious injuries - broken thumb
Cars belonging to over 1000 people washed away
Economic impacts of boscastle?
Insurance companies and premiums rose.
Insurance companies pain est 20 million
Farmers lost there crops.
A lot of money spent on rescues and reconstruction.
25 business properties destroyed
Infrastructure damaged- electricity pylon, bridges, 4 foot bridges, roads
Environmental impacts of bostcastle?
Trees uprooted
Debris scattered
Mud washed into the water
Crops destroyed
Longer terms effects of bostcastle.
Income declined upto 60%. People forced to relocate as couldn’t afford insurance costs.
Tourism declined
Physical causes of Bangladesh food.
80% of the country is a floodplain and delta.
70% of the land is less than 1m above sea level.
Snowmelt from Himalayas.
10% of the land is rivers and lakes.
Confluence of the 3 rivers
Human causes of Bangladesh?
Deforestation in Nepal
Rapid urbanisation in Dhaka
Building of dams in India
Global warming- increased rainfall, snowmelt
Social impacts of Bangladesh flood?
1300 people died
7 million homes destroyed
25 million homeless
Water bourne diseases spread- Cholera
Economic impacts of Bangladesh flood?
Cost of flood was 1 million dollars. Infrastructure destroyed. Money spent on flood defences. - bridges, roads, villages
Reliant on foreign aid.
Environmental impacts of Bangladesh flood.
Over half the land was underwater.
2 million tonnes of rice crops destroyed.
Fields of rotting crops
Half a million cattle and poultry killed
Short term Responses of bostcastle flood?
7 helicopters winched 150 people.
Locals and tourists took shelter in leisure centre.
Human of bostcastle flood?
Human- urbanisation. development of pavements and impermeable surfaces. Sewage and drainage system was very old.
Few flood defences
Extra info on bostcastle
August 2004
Area relies on tourism as 90% of income
Long term responses to boscastle?
£4.6 million flood defence scheme completed in 2008.
Low bridges removed
River widened through boscastle
Flood defence wall built in village centre
River bed deepened by 0.75m
Landowners encouraged to maintain vegetation on valley sides- trees removed
Short term responses to Bangladesh?
Boats to rescue people
Emergency supplies for food, shelter and medicine (water purification tablets) Aid from other countries- seeds, food
£21 million from UK
Long term responses to Bangladesh flood?
Reduced deforestation in Nepal 7 dams built 5000 flood shelters built 350km of embankment built Flood water storage areas created Developed a flood warning scheme
Background info on holderness
Average rate of erosion- 1.8m per year
61 km long
Why is holderness at risk?
Geology- cliffs made of bolder clay- not resistant- easily eroded through corrosion and prone to slumping
Narrow beaches, groynes at mappleton
Powerful waves- long fetch from artic sea
Dominant north easterly wind
Economic impacts of holderness erosion?
Bridlington tourism has received a 30% decline from 1998-2006
Caravan parks are at risk- seaside caravan park- Ultome loosing 10 pitches a year
2 million was spent in Mappleton on defences
Gas terminal at easington- 25m from cliff- responsible for 25% of britains gas supply
Social impacts of holderness erosion?
Negetive equity
30 villages lost since Roman times
Environmental impacts of holderness erosion?
SSSI’s are threatened- the Lagoons at Easington
Causes of hurricane Katerina Storm surge
2004
Low lying land
Change of direction of eye
Delta soil- subsidence- half and inch per year
Flood wall and levees collapsed only made for cat. 3 storm
Where has hard engineering been used? - coast
Lyme Regis- Dorset
South England
Why is Lyme Regis under threat?
Exposed to south westerly waves
Stormy conditions from English Channel
Geology mostly limestone and boulder clay
Rising sea level erodes base- causes landslides
Engineering used at Lyme Regis?
Cobb gate to harbour- new sea wall, slip strengthening and drainage, rock armour
The Cobb- strengthening foundation of the High wall