Coastal Flooding - The great flood of 1953 - A case study

Engraved on the minds of many people living on the east coast of England is the freezing winter weekend of January 31 and February 1, 1953, when a high sea and high tide left a trail of death and disaster in the worst flooding in Britain this century.

During the night of January 31 floods claimed 307 lives, devastated 200,000 acres of farmland, swept cattle, horses, sheep and poultry to their deaths and made 21,000 people homeless. Not until the next morning was it realised that the greatest peacetime catastrophe in this country in living memory had struck a normally peaceful countryside. Over 100 more lives were lost at sea, and 1800 were lost in Holland.

A hurricane of terrific force lashed the North Sea into mountainous waves assaulting sea wall defences along 1,400 miles of coastline, causing damage running into millions of pounds. It was a weekend of horror and heroism during which men gave their lives in attempts to rescue flood-beleaguered victims. Many were later recognised in the Queen’s birthday honours.

It all began on Friday, January 30, when the Meteorological Office sent out a warning of deteriorating weather and of a depression moving down from the north well above the Hebrides.

But probably the only folk who took it seriously were skippers of small craft. By evening a gale running down both sides of the Scottish mainland and small coastal vessels scuttled for shelter.

The following morning the British Railways ferry steamer Princess Victoria (2,694 tons) left Stranraer at 7:45am for Larne in Ulster with 172 passengers and crew and some cars on the lower aft deck. What the passengers did not know was that the vessel was old and unseaworthy and this was to be her last voyage. There were only 44 survivors, 10 of whom were members of the crew.

The sinking of the Princess Victoria was only the first bad chapter in a weekend of disaster. The wind and the sea gathered momentum down the east coast of England during the Saturday and that night the wind reached a speed of 119 miles an hour in some places.

Meteorological Background

The devastating floods of 1953 were the result of a combination of factors producing an effect known as a storm surge, during which water is driven against a coastline resulting in exceptionally high tides.

Tidal records at Southend show the 1953 sea level to be the highest since measurement began in 1911. The frequency of an event of this magnitude is estimated to be once in a thousand years.

The exceptionally high sea level was caused by a deep depression which tracked over the Shetland Islands before turning south-east into the North Sea. The low atmospheric pressure, 976 millibars at the centre, caused the level of the sea to rise by perhaps as much as 0.5 metres.

The associated gale force winds, blowing from the north over a fetch exceeding 2000 kilometres, produced storm waves over 6 metres in height. This caused water to pile up in the southern part of the North Sea.

The geography and topography of the North Sea, becoming both narrower and shallower toward the south, also contributed to the exceptionally high water levels along the east coast of England.

The storm also coincided with spring tides and high fluvial discharges into the North Sea to produce tides over 3 metres above the normal level in the Thames estuary and along the north Kent coast.

Weather chart from David Waugh, “Geography: An Integrated Approach” reproduced with kind permission of Thomas Nelson and Sons.

What protection from coastal flooding is there?

Following the 1953 coastal flooding sea defences were improved. They were tested by a severe storm in 1978 and, although much damage was effected on the coastal towns, only one person was killed and the widespread inundation of 1953 was avoided.

In East Kent, coastal protection works are required for two reasons: to protect the coastline from erosion and to prevent further invasions of the sea.

Defences fall into two main categories, hard defences and soft defences. Hard defences are man-made rigid structures, such as sea walls and breakwaters, usually constucted in concrete and steel. Soft defences are made of unconsolidated material such as sand or shingle such as the beach between Reculver and Minnis Bay which has been stabilised by groyning.

At Coldharbour, between Reculver and Minnis Bay, both hard and soft defences combine to protect a particularly vulnerable area of the coast. The present sea wall is a sturdy concrete structure which is itself protected by a shingle ridge which is maintained by the local authority. On the seaward side of the ridge is a narrow beach, held in place by groynes.

The sea wall near Plumpudding Island has a narrow shingle beach, held in place by substantial rock groynes. Without the beach, the sea wall would come under direct attack by the sea which would eventually undermine and destroy it.

The threat of flooding from Pegwell Bay, at the eastern end of the Wantsum channel, is much less. The bay is sheltered from northerly winds by the Isle of Thanet and the fetch from the south east is limited by the presence of the Goodwin Sands a few kilometres offshore. Into this sheltered, low energy environment, the River Stour carries its sediment load, adding to material transported by coastal processes. The result is an extensive area of deposition and salt marsh development.

The ancient port of Sandwich is at risk from flooding by the River Stour and by high tides. Although much of the old town is several metres above the flood plain, properties alongside the river are subject to occasional flooding. The most likely scenario for serious flooding is the coincidence of a high river discharge meeting a strong tidal flow upstream.

On 19 December 1999, high tides caused the Stour to overtop its banks in the town though there was, in this case, no significant damage to property. The photograph shows the state of the river at the time of the highest tide, looking toward the quay from the northern side of the tollbridge. Downstream of Sandwich, the river was contained between artificial levees constructed to protect the coastal lowlands.

Between the estuary of the Stour and the White Cliffs of Dover, the coastal levels are protected by sea walls and shingle ridges, maintained by the Dover District Council. To the south of Deal there is a wide shingle storm beach with a crest height 4.5 metres above the high water mark and extending over 90 metres inland.