The general levels of extreme floods on the River Tyne relative to the Nungate Bridge in Haddington
Floods in East Lothian
East Lothian is susceptible to flooding due to a combination of its physiography and its regional climate. The steep north-facing slopes of the Lammermuir Hills with their thin soil cover generate a rapid response to heavy rainfall. The rising rivers descend to lowland valleys with broad sections of floodplain, often adjacent to and even within historic and recent setllements. Haddington, and especially the Nungate, has always been prone to flooding due to the position of parts of the town on the floodplain of the River Tyne. Despite the low average rainfall in East Lothian relative to other parts of Scotland, when rain comes it can be torrential - and at any season. Past floods have typically been caused by either an area of low pressure in the North Sea creating a rising north-easterly air stream over the Lammermuir Hills or by a slow moving front or trough of low pressure becoming stationary over the Hills.
On the 7th September 1358 the Nungate convent was on the point of being swept away by a major flood; but, according to legend, it was preserved by the courageous conduct of one of the nuns, who seized an image of the Virgin Mary and threatened to throw it into the flood, unless the impending destruction was averted.
This flash flood on the was a result of torrential two-hour downpour. The flood level of the Tyne in Haddington was recorded as 8' 9" above normal. A tablet erected in the town commemorates the flood of 4th October, when the river rose 17 feet in one hour and inundated the Nungate and the eastern part of the town.
This was probably the largest recorded flood on the River Tyne and the Whiteadder Water in historic times. The flood of the 12th-13th August brought a rise in water level of 10 feet above normal. The High Street as far west as the Town House was under several feet of water which stretched to the gates of Amisfield Park, a distance of over 1 km. Distillery Park, the Nungate, Peffers Place and Brewery Park were similarly devastated. Some 450 homes were flooded and a foot of mud was left in places.
The Biel Burn also flooded, submerging all the low-lying land north and west of West Barns. There was also great destruction along the banks of the Whiteadder Water.
The flood occurred as the culmination of a period of truly exceptional rainfall. 122 mm of rainfall fell between the 1st and 8th August, followed by 153 mm in the next five days. The saturated ground then received a tumultuous 139 mm of rain in the next 24 hours, bringing severe flooding across the county.