presented by: stephen scott how has the uk flood management programme changed over the years? what...
TRANSCRIPT
UK Management of Flooding
Presented by: Stephen Scott
How has the UK flood management programme changed over the years?
What does the future hold?
ContentsIntroduction
UK flood management
Case Study – Thames Barrier
The Future – likely impact of global warming
Conclusions
IntroductionLocation Estimated Financial Cost Estimated Human Loss
Madeira (Portugal) N/A 42 dead, 100 injured
Pakistan $1 - $2 billion 2000 dead, 2500 injured
China $13 billion 3200+ dead, 1,000+ missing
Queensland (Australia) $10 - $25 billion 30-40 dead
Brazil Unknown 51+ dead
- Recent major flooding events worldwide
-Discharge of River Thames 100 times smaller than Indus river- Estimated that 1.5 million people live on floodplain- £80 billion infrastructure at risk (RGS, 2010)
- Flooding in the UK a major concern for those responsible for the management of rivers and coastal defences
Causes of UK FloodingHeavy rainfall or thunderstorms over short period of
timeTewekesbury – 2007Boscastle -2004
UrbanisationDeforestation Cultivation
Tidal Surges – most likely form of flooding in the UKKent & Yorkshire - 2007
UK Flood managementFlood management evolves as a result of social
and economic conditions
Bear the Loss – Do NothingModify Damage Susceptibility – Land Use PlanningModify the Flood – Flood ProtectionModify the Loss Burden – Disaster Relief
Land Use PlanningFlood alleviation technique
- reducing impact of flooding
Manages flooding risk to development in the flood plain
Flood map of River Avon running through Bristol
‣ Floodplain development managed by use of FRAs
Land Use PlanningFloodplain divided into 3
zones (1-3)
Functional Flood Plain (3b)‘land where water has to flow
or be stored in times of flood’
Limited use – No reduction in Volume, Flood routes Maintained
Structural Flood DefencesHard engineering preventative technique
Developments in mathematical modelling in the 1980s created powerful tools for flood management
Flood Gates, River Walls, Sea Walls, Modification of River Channel etc.
Thames BarrierOpened in 1982, costing £365 million estimated
to protect £80 billion infrastructure
Designed to protect against a storm with return period of 1000 years (up until 2030)
Consists of 10 movable gates spanning 520m
The FutureGlobal warming: increase in coastal waters, tidal
surges and higher intensity rainfall
Structural defences too expensive to maintain
Increase severity and spread of floodwaters
Greater threat to cities as the urban sprawl continues
Humber EstuaryCurrent Flood Defences
Flood Defences 2060
Green RoofsNot a new technology
Utilised heavily in Germany 10% of all roofs are ‘green’
Shown to attenuate runoff- reduces runoff rate and flow volume
Some studies show a 50% reduction in runoff (Rowe, Monterusso, Russell, 2003)
Weather Control?Cloud seeding
Utilised in Olympic Games?
Not designed to prevent rainfall but to control where it falls by causing moisture to condense prematurely
ConclusionsLand use planning and structural flood defences
currently are major parts of the UK flood management strategy
Flood management over the next 50 years looks set to be dominated by global warming
Management strategies may have to move from traditional ‘hard engineering prevention’ to a more ‘risk management strategy’