60 BemarTcs on tJie Heport of the Water Commission. 



The Upper Nepeau sclieme involves the necessity of construct- 

 ing a conduit of sixty-three miles in length. This would not 

 only be costly to make but costly to repair, and consisting as it 

 would sometimes of pipes, sometimes of tunnels, sometimes of 

 open conduit, passing under roads and over roads, would be 

 exposed to a great variety of risl\s of damage. It i.s necessary, 

 by this scheme, to go to this distance from Sydney to get the 

 requisite altitude, which is fully attained at Pheasant's iS"est, the 

 point where the water is first intercepted, and which is four 

 hundred and twenty feet above the level of the sea, or two hundred 

 and eiiJjhty above the top level of the water in the existing Orown 

 Street reservoir. This is an elevation sufBcient to deliver the water 

 with good pressure on the top of the highest roof in -Sydney, but 

 then, unfortunately, this advantage is wasted in the course of 

 of brinujing the water down. It is impossible to find any route 

 by which the channel can be maintained at the desirable height, 

 and the storage reservoir at Prospect could only deliver water 31 

 feet above the top level of the Crown-street Reservoir, so that 

 all the difi'erence between 280 feet and 31 feet is forfeited on the 

 journey between Pheasant's Nest and Prospect. This remaining 

 elevation of 31 feet is largely lost in delivering the water into the 

 Crown-street Reservoir, as the distanc-e to be traversed between 

 these points is 21 miles, of which about 11 would be in pipes. So 

 far, therefore, as pressure is concerned, we shall gain little advan- 

 tage over the existing system. We shall not have sufficient force to 

 drive machinery, nor to supply the upper stories of houses in the 

 more elevated parts of Sydney, and it would be necessary to have 

 recourse to pumping to supply the higher suburbs. This loss of 

 elevation would be avoided to the extent of 68 feet by the 

 adoption of Mr. Grrundy's proposal for a reservoir at Bull's Hill, 

 but this would involve piping all the way thence to Sydney, and 

 the scheme was abandoned by the Commissioners, on the ground 

 of its heavy extra expense. 



The construction of the storage reservoir itself is not free from 

 objection. It is to be formed by means of a dam which at its 

 deepest point would be 80 feet. This is a great height, and 

 would justify considerable anxiety about its security. Should it 

 burst, the damage would be very serious ; it would take some 

 months to repair it, and the reservoir could not be refilled under 

 a twelve-month. Moreover, a large amount of the labour and 

 expense involved in the construction of this dam would be wasted, 

 seeing thai only the upper 25 feet of the water could be drawn 

 off. Fifty-five feet, therefore, of height of the dam would serve 

 no useful purpose so far as the storage of water is concerned. 

 The reservoir would hold 10,OUO millions of gallons, but 3000 

 millions would remain unutilised, unless pumped out, as they 

 would lie below the level of the outlet. 



