122 METROPOLITAN WATER SUPPLY. 



Also, I have to remark that as the proximity of St. Leonard's, 

 across our line harbour, to the business parts of Sydney, will 

 insure a rapid extension of population there, so we should bear 

 in mind that such future large suburbs will require a good water 

 supply ; and as I am confident that no proper supply for that 

 locality can be obtained from the North Shore side, so may we at 

 once fairly contemplate our ability under my scheme to send on 

 the waters there from Sydney, by continuing the high-pressure 

 main across and under the salt water of the harbour, with the 

 view of supplying a receiving reservoir on the highest point of 

 its neighbourhood — a desideratum which would be obtainable 

 there in such cases during the hours of night, when the machi- 

 neries in Sydney, driven by water engines, and by turbines, would 

 be at rest, and not consuming the water from the high-pressure 

 main. 



And failing the application of the high pressure mains for the 

 service of all the North Shore, we could under my scheme, and 

 in same manner, supply a receiving and distributing reservoir 

 there, at an elevation nearly as high as could be commanded from 

 the proposed relieving and distributing reservoir at Waverley. 



It is, however, particularly noteworthy that a water delivery 

 in pipe, by the bottom of the harbour across to the heights of 

 the North Shore, would be far easier, safer, and less expensive by 

 the high pressure than by the low pressure plan. By the high 

 pressure a singularly small pipe in spring-steel, or in iron with 

 elastic joints, enamelled inside and outside, and lowered to the 

 bottom of the harbour, would supply a large population with 

 abundance of pure water ; whereas it might be very difficult to 

 place, in a similar manner, the far larger pipe to do the same 

 duty under a sluggish delivery by the low pressure plan from the 

 "Waverley reservoir. 



On the vexed question of adequacy of watershed and water 

 supply from my proposed gathering-ground, or indeed from any 

 gathering-ground, I have just received the most valuable infor- 

 mation from Mr. Gr. Gordon, the Hydraulic Engineer-in- Chief of 

 Victoria, who, in reply to a recent question of mine, words a 

 part of his letter to me in the following manner, and which I 

 feel at liberty to use for our own general information. Mr. 

 Gordon writes thus : — " I am sorry that I can give you no 

 gauging of the flow of the river Plenty that would be of any use 

 to you. The discharge is so much beyond the requirements of 

 the Yan Yean that the river has never been regularly gauged 

 except at its lowest state. It has been as low as 1,800,000, 

 and on one occasion, I am told, as low as 1,000,000 gallons in 

 the twenty-four hours ; of course that was in the height of 

 summer. From some observations of other rivers I find the total 

 discharge to be 130 millions of gallons per square mile per 



