distance it is carried the more it will be diffused. It must be
remembered that the foregoing data are only applicable to the
locality they relate to, although after obtaining the necessary
information similar diagrams can be made and used for other
places; but enough has been said to show that when it is
necessary to utilise the full effect of the currents the sewage
should be discharged at a varying time before high or low
water, as the case may be, according to the height of the tide.




CHAPTER V.

VOLUME OF SEWAGE.


The total quantity of sewage to be dealt with per day can be
ascertained by gauging the flow in those cases where the sewers
are already constructed, but where the scheme is an entirely
new one the quantity must be estimated. If there is a water
supply system the amount of water consumed per day, after
making due allowance for the quantity used for trade purposes
and street watering, will be a useful guide. The average amount
of water used per head per day for domestic purposes only may
be taken as follows:--


DAILY WATER SUPPLY
(Gallons per head per day.)