After the 1978 flood, a relief channel was dug. In the late afternoon of 21 September 2001 the flow in this channel reversed, and so it may be relevant to review the events of 1978 and subsequently.
22 houses in the vicinity of the Bin Brook were flooded in May 1978 and 9 others were surrounded by flood water. There was nearly a repeat in February 1979.
60 mm of rain fell in the 24 hours preceeding the 1978 flood, a rainfall that was said to have a return period of 30 years. Before this, the ground was already unusually wet.
A committee was set up under the chairmanship of Dr Chris Johnson (54 Gough Way). He led a difficult negotiation with the City and County Councils, and the Anglia Water Authority, during which each of these three bodies claimed that the others had full responsibility.
The committee received active help from Councillor Ruth Cohen (25 Gough Way). On 11 May 1978 she wrote to the chief executive of the City Council complaining that the AWA had failed to give any warning of the flood. This resulted in the erection of the gauge board behind 37 Gough Way, and the owners of the houses with low floor levels were issued with instructions on how to interpret it. These gave the level of the top of the culvert as 31.40 (presumably the units are feet), and the level of the lowest floor as 31.82 (54 Gough Way). The flood reached 33.25. I believe that in 2001 it was about 0.2 higher.
In 1978 the Bin Brook was still an ``award drain''. This dated back to the St Giles enclosure award of 1805, which specified that the brook be 10 ft wide and 4 ft deep. The diameter of the Gough Way culvert is 5 ft. A memo from the City Engineer in August 1978 remarked that it had not been possible to trace the design calculations for the culvert, which had been constructed by the developers of the estate in consultation with his predecessor.
He also gave the opinion that the level of the Cam had been a factor in the Gough Way flood. This was contradicted in a report by the AWA in September 1979. This report gave the culvert capacity as 2.25 cubic metres per second and recommended that a relief channel be dug so as to provide a total capacity of 4 cubic metres per second. This recommendation followed from a cost-benefit analysis: the damage value at July 1979 prices had been 60k and the flood alleviation scheme would cost 28k. The supreme importance of regular maintenance was stressed, at an estimated cost of 3k per year.
The relief channel was dug in 1982. By 1985 its banks had begun seriously to slip.
In August 1978 a planning application for land adjoining 116 Barton Road was rejected. One of the reasons cited that the land was in a recorded flood plain and any further development would aggravate the existing flooding problem.
PVL
4 November 2001