Water on the land Case studies.

Location

• North Cornwall in the South West of England.
• Small Village On Cornwall's North coast. Main economical activity is tourism.
• 3 rivers flowing through it.
  • River valency 
  • River Jordan                                                                                                               

Causes

Physical

• Rainfall of 1,400 million litres in just 2 hours.
• wet summers.
• steep sided valleys funnelling water towards boscastle.

Human

• Large amount of buildings on flood plains.
• Water can't infiltrate - too many impermeable surfaces.
• bridge acted like a dam and stopped water getting through.
• Large plants got swept into river and blocked the water.

Effects

Social

• Stress and anxiety of local people.
• Visitor centre destroyed (Also economical)
• Rescue services had to mount the largest peace time rescue operation in history.
• 4 footbridges washed away.

Economical

• Local economy was devastated the area relies on tourism for 90% of income.
• 50 buildings flood damaged.

Environmental

• Mud and debris left in lower part of the village.
• pavements and gardens destroyed.

Responses

Short term

• Helicopters.
• Rescue.
• Evacuation.
• Flood warnings.

Long term

• Wider span bridge.
• Removed lower bridge.
• Move trees neer to river.
• New flood defence wall.
• Relocate defence walls.

• Located in Asia, Near India. - soil is very fertile.
• Confluence of two major rivers.

Human Causes

• Deforestation in Tibet and Nepal means less water is being soaked up so surface run off and soil erosion will increase and cause higher river levels.
• In Dhaka and other urban areas, rapid growth of the amount of impermeable surfaces, resulting in more surface run off.

Physical Causes

• Snow melting in the Himalayas during summer add to the amount of water flowing into rivers - made worse due to climate change.
• Tropical cyclones cause coastal flooding due to storm surges.
• The river Ganges is used for irrigation, increasing deposition and reducing channel capacity.

Effects 1998

Short term

• 60% of the country was flooded.
• Capital city Dhaka was under water for weeks.
• Crops were lost/Contaminated.

Long term

• Hundreds of people killed.
• Millions were made homeless.
• 900 bridges and 15,000 km of roads were destroyed.
• loss of income.

Effects - 2004

Short term

• River had risen above danger levels.
• over-topped flood protection embankments.
• Effected 36 million people.

Long term

• Leaving contaminated and general destruction.
• loss of income.

Hard Engineering

• Reinforced concrete walls with metal flood gates to access by people and flood gates.
• Gabions (baskets filled with stones) to protect walls and embankments from erosion.
• Earth embankments.
• Straighten river to allow it to flow faster.

Soft engineering

• Building materials approved by English heritage to remain in keeping with existing architecture.
• Fishing platforms, street lighting and replanting to improve the environment.