113741
Description
Flashcards by Molly Atkinson, updated more than 1 year ago
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Created by Molly Atkinson
over 11 years ago
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| Question | Answer |
| Location | Boscastle is a small village found in the South-West of England, near the Bristol Channel, along the coast. |
| When | The flooding in Boscastle happened on the 16th August 2004. |
| Causes | Flash floods which happened after a massive amount of rain fell in just eight hours that afternoon. · A 2m rise in river levels in just one hour, causing the river to burst its banks. · Large amounts of impermeable surfaces. · Bridges over the river reduced its flow. · Heavy rain o 8.9 cm in an hour o 2.4 cm in 15 min · River speed o Excess of 4m/sec o 2m rise in 1 hour · Warm climate à frontal rain · Narrow river à hold small amounts of waterà build up of waterà no where to go à flood · Impermeable surfacesà surface run off à increase risk of flooding · Small drainage basin + steep slopes à increase risk of flooding · Climate – low temperatures means a low evaporation rate. |
| Effects | · 75 cars damaged · 5 caravans washed into the sea · 6 buildings washed into the sea · Contamination of water with sewage · 100 homes/buildings damaged beyond repair · 90% of economy was based on tourism=loss of revenue · Insurance costs went up. |
| River management | Barriers or dams put in to control the river’s flow. · Raising the banks (creating levees) of the river, and widening and deepening the river to increase the amount of water it can hold. · Zoning – only allowing people to build along certain parts of the river to reduce the amount of impermeable surfaces. · Afforestation to increase the amount of interception and therefore storage of water, meaning the there is less water in the river so the risk of flooding is decreased. · River widened and lowered=increased capacity =could hold more water · Overflow Culverts put in place to re-direct excess water · Underground pumps put in place so flood water couldn’t mix with sewage |
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