A case study of the Boscastle floods in 2004 about the impacts and the management

1. Boscastle (2004)

2. Effects
• Acts like a funnel because of its location
• A lot of vegetation
• Steep-v shaped valley
• Was high tide at the same time
• Very wet summer
• Remains of Hurricane Alex
• 440 million gallons water, 75mm of rain in 2 hours
• 100 cars destroyed
• No one dies
• Bridge across river caused many problems

3. Physical Impacts
• Channel changed- it widened and deepened by force of water, increasing the hydraulic radius
• Trees up-rooted- it was a steep sided valley
• Wildlife and habitats destroyed especially on the banks of the river
• Deposition on the flood plain- positive impact 20cm of sediment deposited
• Deposition in the channel which could cause the capacity of the channel to be reduced so there is
a increase in the risk of flooding
• Fuel and oil leakages into the harbour and debris washed into the sea
• River Valancey cut itself a new channel whilst in flood

4. Social Impacts
• Community fragmented
• People had to rent property outside the village
• Children had to go to different schools
• Insurance claims take a long time and can cause stress
• Disruption to people’s lives
• Sewage main burst- weren’t allowed in homes because of health and
safety

5. Economic Impacts
• 25 business destroyed
• 50 building's suffered flood damage
• 4 foot-bridges washed away
• Visitor Centre destroyed
• Pavements and gardens washed away
• £20 million in insurance claims
• 50 cars washed away
• Rescue operation
• Lost income of tourism for a period of time so 20 accommodation providers shut down
• An increase in the amount of tourists after the flood because of the media attention it got
• Caused long-term disruption to the village during the re-building phase

6. Flood Management and Re-Building
• £4.6 million project
• Historic village with land owned by the national trust so re-building had to be within certain guidelines with the national
trust
• An area of outstanding natural beauty
• Environmental agency in charge of rebuilding the village
• A lot of material reclaimed from flood and used in re-building phase. 300 tonnes of walling stone
• Multi-agency scheme- Halcrow, construction company involved
• 2 main objectives- Increase capacity of river channel and reduce structures causing blockages

7. Flood Management
• Straightened the river and made it wider and deeper to increase capacity
• Trash screens- to stop tree/boulders from blocking the channels. Require maintenance
• Raise car park and widen river channel next to car park and create a walkway next to the river
• Ensure trees and vegetation are removed that are directly next to the river
• The bridge was made so it was higher above the river to prevent any blockages
• New flood walls
• More trees planted within the drainage basin to hold more water back
• New sewage system
• Created an area of slower flow where large sediment can be deposited and the river can spread out so it can behave naturally
• 1 in 75 year flood defence