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49
On inspecting the houses, I found that the water had risen
about 18 inches above the ground floor' Most of them showed the
height the water rose, by the dampness of the walls. It appeared
on enquiry that the houses were flooded in a similar manner a few
years before; but the more recent flood appeared to be out of all
proportion to the amount of rain-fall preceding. The importance
of this flood depends on the fact, whether it was an accidental event,
due to an extraordinary fall of water in the Lea Valley, or whether
any change had taken place on the banks of the river, by which
flood waters are more confined to the course of the stream, or that
their exit by the natural channel is restricted.
I am indebted to Mr. W. B. Bryan, Chief Engineer to the
East London Water Company, for the following letter giving details
as to the gaugings taken at Field's Weir on the 6th and 7th February
last.
East, London Waterworks Company,
Engineer's Office, Lea Bridge, Clapton, N.E.
March 10th, 1897.
FLOODS IN THE LEA VALLEY.
Dear Sir,—I find, on investigation, that far greater volumes have
passed over Field's Weir in years gone by, on many occasions, than on the
6th February last.
The quantity gauged on that day was 945 million gallons. In November,
1894, 1114 millions passed, but the November, 1894, floods were very much
smaller at Lea Bridge than the floods of the 6th and 7th February, 1897. It
must be noted, however, that the volume of water at Lea Bridge is very
much in excess of that at Field's Weir. I must, however, point out that
for the four days preceding 6th Fobruary the daily flow was 810 million
gallons, while in November, 1894, the flow only reached about 645 million
gallons daily on the two preceding days. Consequently the whole of the
valley had a greater accumulation of water in February last than in
November, 1894, although a much greater quantity passed on one day in
1894 than in 1897. The normal level of the water in the River Lea at Lea
Bridge is 20 80 above Ordnance Datum. In 1894 the flood only caused a rise
in the river at Lea Bridge of from 7 to 8 inches, but in February last the
rise was 1 foot 9 inches. In each case the whole of the sluices in the waste
weir were raised, giving full vent to the flood waters, and the level of the
water below the weir was seven inches lower than at Lea Bridge, and at the
boundary of the Company's property, some hundreds of yards lower down,
D