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Sanitary Circumstances.
25
PUMPING MACHINERY.
The most important operation at the works is the pumping
of the sewage, so that the sewers from the different districts have
at all times free discharge, and machinery is provided constantly to
lift day and night the whole of the drainage flow ; this averages
from three to four million gallons per day in dry weather, but is
augmented considerably during times of rainfall by large volumes
of storm water.
If pumping operations ceased for any considerable length of
time, sewage would collect in the system of sewers throughout the
district until the lower parts of the district were flooded.
To ensure that such an event should not occur, it has been
the object of the Board to provide pumping machinery largely in
excess of the capacity required for the average dry weather flow.
At present the machinery installed is capable of lifting fifty
million gallons, or 223,214 tons of water per day. Of course, it is
not expected ever to have fifty millions to pump in twenty-four
hours, but on occasions of sudden rain storms, the machinery has
gradually to be set in motion, one engine after another, until
within, say, thirty minutes, the pumps may be lifting 4,500 tons
per hour, or twelve times the ordinary dry weather flow, and this
rate of pumping may have to be continued for many hours.
It might be suggested that, in a district where so much is done
to provide that the rain water goes direct to the river by a special
system of drains, there should not be much find access to the
sewers; such would be the case, if the whole of the houses, as well
as the streets, were provided with a double system of drains, one
for rainfall and one for sewage.
In Barnes and Richmond, however, a large proportion of the
roofs are still drained to the sewers, and it is the roof water which
causes the sudden fluctuations, and adds large volumes to be