GCSE Case Studies

2007- June- July- 350% more rainfall than average

Shrewsbury- Meander= slowed down river Velocity, causing it to flood, and the surrounding town to be cut off.                                   

Tewkesbury- On a confluence, meaning the river has a high discharge so it flooded quicker. Also near the mouth= slower velocity= couldnt retreat to the sea in time.

Weather- 20th July 2007- 90cm of rain, and as the ground was already saturated due to 350% more rain than average, the water couldn't infiltrate= flood.

Human- Middle and lower courses of river are urban as land use= impermeable surfaces and decrease in vegetation= less interception and more surface run off= flood.

Businesses- Tewkesbury- flooded= resources destroyed- economic impact.

Economic-

• Homes and roads flooded- gov money to re-build, and insurance
• No insurance on flood plain

Environmental-

• 10.7m heigh in Gloucester
• 10.4m level overall
• Severn and Avon widened at confluence
• Clean water treatment plant flooded and conutryside- wildlife

Social-

• 300,000 in risk of losing power- 1/2 mil people no electricity
• 350000 risk of no clean water
• Army/ resue teams/ 8 severe flood warnings/ fire bregade moved/ Key Street evacuated/ roads cut off/ people working for 36 hours

Management-

• Flood walls and stone embankments (Shrewsbury)- demountable not reasable
• Earth embankments- confluence areas between Gloucester and Worcester
• Aluminium temporary barriers (Shrewsbury)- heigh can be changed

Positive-

• Demountable barrier= less visual impact on historic town
• 74 homes in Shrewbury were not flooded in the next flood- greatly reduced risk and anxiety
• Temporary defences same in all places so share parts, permenant blend into town

Negative-

• Not economically viable for more flood defences (apart from Frankwell) in Shrewsbury
• Shrewsbury £45,000 in 2016 Winter- overall £3.5bil
• Hard- Engineering

Why?

• Caravan parks/ holiday homes flooded, 300 homes, main road and water tretment plant endangered,

Management-

• Tear down sea wall for managed retreat, 4 miles new defences
• New saltwater marsh, Shingle embankment
• 7km of new flood bank from onsite clay/ 15 years to do

Positive/ Negative-

• 15 yrs, £28mil- largest coastal flood realignment scheme
• Sustainable and community involvemnet- 70-80 men at once
• New ditches and ponds/ new wildlife reserve for tourism/ new birds for tidal habitats
• Fresh water habitats on outskirts
• 60,000tonnes of rock by barges from Norway

Why?

• Unstable ground/ risk of winter storms
• Sea wall becoming undermined/ groynes deteriorating
• East of town landslides, drainage system inadequate to cope
• Beach slowly eroding, beaches unattractive

Management Scheme-

• Sea wall replaced and rock armour to protect it
• Masonray groynes replaced with wodden groynes
• Land stabalised with steel pipes
• Replenished beach- requently build it up