F763: Global Issues Section A - Environmental Issues Earth Hazards Coastal flooding in the North Sea, 1953 Basic facts and figures • 1 February 1953 Physical factors that led to the flood • • • • • • Storm surge – strong winds from north – east pushing water south Intense depression so sea level rises (1cm per 1mb fall) – more than 5.6m a.m.s.l in some locations. High spring tide North Sea narrows to south Heavy rain so rivers swollen Shallow coastal waters and low – lying coast (20% b.s.l and 50% of Netherlands less than 1m a.s.l) Human factors that led to the flood • • • • • Dredging of sand offshore and salt – marshes reclaimed Neglected sea walls Rapid urbanisation at the coast Encroachment onto natural flood – holding areas No warning system existed in 1953 – local radio stations only operated during the day so people were unable to prepare. Social Impacts • Approximately 2000 deaths (drowning) and 300 in the UK Economic Impacts • • • • £50 million damage in the UK alone 9% of Dutch productive farmland was flooded Seaside resorts hit hard (e.g. Southend) Coastal routes cut e.g. railways Environmental Impacts • Land lost to salt flooding – some abandoned Short – term responses (emergency rescue) 35 000 evacuations in the UK e.g. Canvey Island and evacuations of livestock Amateur radio operators went into the affected areas with their equipment to form a voluntary emergency radio network • Search and rescue – US Army sent helicopters from German bases • Property pumped out • Army called in to seal sea walls Long term responses (planning and management) • • • • • • • Early warning system with sea level monitoring – provides up to 36 hours warning of a potential event. The Netherlands developed to Delta Works – an extensive system of dams and storm surge barriers e.g. Eastern Scheldt Storm – Surge barrier in Zeeland, southeast Netherlands. Defences can now withstand a 1 in 10000 year storm – surge – there have been no catastrophic floods since 1953. Sea walls raised or managed retreat accepted (areas allowed to flood to take pressure off sea walls) Flood barrages built in the UK following the report of Sir Hermann Bondi into the storm surges e.g. the Thames (in 1982) and the Humber estuary (in the 1970s).