THE WATER SUPPLY OF SYDNEY. CIII, 
I am quite in accord with the Chairman’s remark that 
the future requirements should be forecasted, so as not to 
leave a narrow margin to execute the necessary storage 
reservoirs. In connection with this, the investigations 
made by the Chairman will form a valuable guide; this 
opinion I formed while having the advantage of seeing the 
results during the investigation. I do not know of another 
instance, at any rate in any of the States, where such 
valuable information has been collated, from which the 
question of periodicity of rainfall can be deduced. 
In estimating for future requirements, the prospective 
population to be served and existing storage has to be con- 
sidered. ‘Taking the population supplied in 1906-7 as com- 
pared with 1907-8, the increase is about 12,500 or about 2%, 
but taking the population for a decade, June 1898 to 1908, 
the average increase per annum is about 4%; taking this 
annual increase as a basis, the estimated population in 1912 
is 690,710, and assuming that the consumption is 50 gallons 
per capita, which is a very liberal estimate in view of the 
present consumption, the quantity which would be drawn 
daily from Prospect would be about 393 millions per diem, 
allowing for evaporation. Taking the storage at Cataract, 
assuming it full at 21,411 million gallons, and only 2,700 
millions available at Prospect, would give a storage equal 
to 610 days. Iam only assuming that 2,700 million gallons 
are available at Prospect, whereas the quantity available 
to gravitation level is 5,503 million gallons. I think that 
it will be admitted that as far as storage capacity is con- 
cerned the metropolis is ina safe position for some years to 
come, somewhat different prior to the 1902 drought. Unfor- 
tunately we have heavy rains in the metropolitan area 
with very poor result on the watershed, while the rain 
reduces the consumption in the metropolis it adds very 
little to the storage, and hence the value of the high dam 
to store the rain when it does fall. 
