A giant bulwark rises in the Thames as a flood barrier
Driven by high winds and tides, the great surge of water spills over the embankments of the Thames River and sweeps across dozens of square miles of London, endangering countless thousands of people. More than a quarter of a million homes, offices and factories in such low-lying areas as Westminster, Hammersmith, Lambeth and Southwark are inundated. In the streets, thousands of cars are left stranded. In central London, the underground is paralyzed, bridges and tunnels are closed. Hospitals struggle valiantly to maintain services, their task made all the more difficult by power blackouts, loss of telephone service, contamination of the water supply and the difficulty of mobilizing rescue teams. The Houses of Parliament and New Scotland Yard stand in several feet of water. Total damages from the great Thames flood: more than $6 billion.
This scenario is not the product of an avid Hollywood scriptwriter. It is a grim projection by British experts who know only too well that the apparently placid Thames can turn with little warning into a terrifying torrent. To forestall the disaster that a "worst case" Thames flood would produce, British engineers are rushing to complete by the end of 1982 an extraordinary project: a giant, movable steel and concrete flood barrier that in normal circumstances will allow the passage of large ships but rise up during flood threats to block the menacing waters.
Lying upriver about 96 km (60 miles) from the North Sea, London has through history been swamped by the rampages of the Thames. During a flood in 1236, reports one chronicle, "in the great palace of Westminster men did row with wherries [small skiffs] in the midst of the hall." In his diary entry for Dec. 7, 1663, Samuel Pepys wrote: "There was last night the greatest tide that ever was remembered in England to have been in this river: all Whitehall having been drowned." As recently as 1978, the Thames came within 30 cm (12 in.) of topping flood walls.
For centuries, London and other communities along the lower Thames have been raising their embankments. After a sudden flood in January 1928 killed 14 people, including four youngsters asleep in a Westminster basement, the walls along the Thames were elevated to more than 5 meters (17 ft.) above the mean water level. More recently, the height has been increased to nearly 6 meters (19 ft.). But even these towering embankments could not cope with an extreme combination of circumstances. While Thames tides normally do not exceed 4.6 meters (15 ft.), the level can be pushed far higher by sudden onslaughts of water. In 1976, a 2.4-meter (8 ft.) surge was recorded on a low tide. If such a surge came atop one of the highest tides, it could raise the river to 1.2 meters (4 ft.) above the Thames' embankments and cause, in the words of the Greater London Council, "a catastrophe for the capital on the scale of the Great Fire of London or the Black Death."