rivers - case study: sheffield flood

Question 1

information about area and flood

Answer 1

south yorkshire, north England
570, 000 population
urban centre of north

in June- July 2007, several periods of extreme rainfall caused flooding in England and Wales

Question 2

impacts of Sheffield flood

Answer 2

• wettest may to July since 1766
• River Don flooded (15ft higher than usual)
  –> increased flooding
• 6ft flood in Sheffield Wednesday
  –> millions of £ to repair
• 1200 homes flooded
  –> inflation and increase in homelessness
  -1000 businesses flooded
  –> affects income
• Meadowhall centre closed due to flooding
  –> loads of job loss: loss of income
  –> large loss of money for government
• 13 year old swept away and 68 year old man died crossing the flood
• loss of farmland and cattle
  –> lack of food
  –> loss of jobs (farmers and stock ppl in supermarkets): loss of income
• M1 closed partially for precaution
• 13000 without power for days
• local businesses suffered: £15 milli in damage
  –> already low income

Question 3

what are the main reasons for flooding

Answer 3

rainfall
rivers and the landscape
urbanisation
drain infrastructure

Question 4

rainfall causing flood

Answer 4

wettest june since 1882
- prolonged rainfall (may - july)
- 110mm of rain over 10 days caused saturated soil and the drains couldn’t cope with the amount of rainfall

Question 5

rivers and the landscape causing floods

Answer 5

• ‘city of seven hills’: steep so surface run-off occurs quickly
• upper course of the Pennines flooded because it couldn’t store the rain or regulate river flow like usual
• confluence of 3 rivers holding rainfall
  –> volume of water increased hugely when river Loxley and Rivelin joined AND backlog of water in River Don (too full) went up along Rivelin and Loxley, overflowing
  –> trees fell onto rivers Sheaf, Loxley and Don

Question 6

urbanisation causing flood

Answer 6

• most of Sheffield is full of impermeable surfaces (concrete/brick) so no rainwater can absorb into it: rely on drains
• houses were built on flood plains so the water overflowing from the rivers had no soil or tree roots to absorb it

Question 7

drain infrastructure causing flood

Answer 7

• only rely on drains for rainfall coping so the drains were overwhelmed with extreme flows of water
• drains were already blocked and overflowing as run-off was coming
• sheffield city council denied blame the drains caused the flooding
• city’s drainage system was prepared for rainfall that may have occurred once in 30 years