Floods Case Studies

Floods Case Studies

1. Tewkesbury

   • July 2007
   • 13 dead
   • 40% of household and 25% of commercial claims settled by mid-November
   • 414 mm average rainfall across England and Wales
   • 7000 businesses flooded
   • 120,000 household insurance claims
   • 27,000 commercial claims
   • 18,000 motor claims
   • £3 billion overall cost to insurers (biggest ever in British History)
   • Cut off by flood water
   • 60 - 80 people slept in Abbey
   • M5 was closed
   • Homes near to river under several metres of water badly polluted with sewage
   • Barrier of steel and 6000 sand bags used to protect local power station
   • 140,000 without water for a week
   • In December 2007 some people still living in caravans
   • One restaurant had an estimated loss of £80,000
   • Options for protection in the future
     • Building walls
     • Dredging
     • Straightening river
     • Very expensive
     • People against because changing nature
   • 1 in 200 year event
   • Floodplains of river Severn and Avon
   • Environment agency has removed some bridges

2. Bewdley

   • River Severn
   • Half mountainous half flat
   • Water can't sink through hard rock slopes so more runoff
   • Reservoirs used to help control river
     • Very full
   • Short lag time
   • Relief rainfall in Welsh mountains
   • Woodland only 10% of River Severn catchment
   • Nearby mining and quarrying can block up river channel
   • Ground was already saturated
   • Lots of rain caused by large depression
   • Peak discharge of 496m/sec
     • 4 days after downpour
       • Because of large catchment area
   • Extensive flooding 3 times in 6 weeks
   • More than 140 properties flooded
     • Many to a depth over 1.5m
   • Many affected buildings were listed
   • Interrupted businesses
   • Evacuation of residents
   • Transport area disrupted
   • 7 Options to prevent future flooding
     • 1.Do nothing
     • 2.Continued maintenance
     • 3.Upstream storage (dam)
     • 4.Hard defences in Severnside
     • 5.Upstream storage storage and bypass tunnel
     • 6.Dredging
     • 7.Bypass tunnel

3. Saint Asaph and Ruthin

   • Glasdir estate built on flood plain
   • Residents told millions was sent for protection
   • 3 layer defnece
     • a new link road with culverts to drain water away from houses
     • a bund wall (similar to levee) made houses higher up
       • Designed to proect against 1 in 1000 yr flood
     • Floor levels in houses 20cm above bund
   • 1 in 200 yr flood
   • Debris piled up against grills on culvert
     • Not up to industry standards
   • Link road acted as dam for river
   • Sand bags put on top of bund
   • Home owners formed a committee to get answers
   • Plan said houses should have been built 55cm higher than they were
   • Surrounded by steep hills + fast flowing rivers
   • Planning to raise bund
     • Locals unhappy about looks
   • Vegetation blocking main river channel