Hints from the Health Department. Leaflet from the archive of the Society of Medical Officers of Health. Credit: Wellcome Collection, London
[Report of the Medical Officer of Health for Poplar, Bromley, South District comprising the parishes of All Saints Poplar and Bromley Saint Leonard]
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ROYAL OBSERVATORY, GREENWICH. Excessive Rainfalls in Short Periods of Time, 1861-1895.
Date. | Amount and Period. | ||
---|---|---|---|
1865 —May | 23 | 0.54 in. fell in | 17 minutes. |
1865—June | 30 | 0.48 „ „ | 17 „ |
1865—August | 23 | 1.09 „ „ | 2½ hours = 150 m. |
1867—July | 26 | 3.58 ,, ,, | 10 hours1 |
1868—May | 29 | 0.52 ,, ,, | 8 minutes. |
1874—July | 11 | 0.87 ,, ,, | 25 |
1875—August | 7 | 0.93 ,, ,, | 30 „ |
1877—August | 22 | 0.70 ,, ,, | 30 „ |
1878—April | 11 | 2.51 „ „ | 13 hours* |
1878—May | 7 | 1.00 ,, ,, | 50 minutes. |
1878—June | 13 | 0.65 „ ,, | 30 „ |
1888—June | 26 | 1.10 „ „ | 1 hour = 60 m. |
1888—July | 18 | 0.78 ,, ,, | 30 minutes. |
1888—July | 30 | 1.70 ,, ,, | 2 hours = 120 m |
1890—July | 17 | 0.73 ,, ,, | 1 hour = 60 m. |
1891—August | 2 | 0.52 ,, ,, | 30 minutes. |
1893-July | 12 | 0.64 ,, ,, | 40 „ „ |
1895—September | 7 | 0.75 ,, ,, | 32 „ |
*Great floods. | |||
1895, Sept. 12. | W. H. M. Christie. |
The area drained in Sussex Street is 180,000 superficial feet. The
sewer has a fall of one foot in a hundred feet; therefore, the velocity
of the sewage flowing will equal 275 feet per minute,* and the sewer
* The formula used was :—
V = 55 x (V D x 2 F)
V = velocity in feet per minute.
D = hydraulic mean depth.
F = fall in feet per mile.
Then if A = section area of current of fluid, VA = discharge in cubic feet per
minute.
The hydraulic mean depth is one-fourth the diameter in circular pipes.