XXV111. ABSTRACT OF PROCEEDINGS. 



There is no alternative for Sydney, but to look forward 

 to its future water supply being provided from storage 

 reservoirs, hence the necessity for jealously conserving 

 every square mile of the present catchment area, and if 

 possible making additions to it, as I have shown can be 

 done at the north and south ends to the extent of 140 

 square miles, making a total of 490 square miles of clean 

 gathering ground, from which it is possible to gravitate 

 the water in the city, an inestimable boon, as will be 

 discovered later when resort has to be made to the waters 

 from less favoured country, when filtration will be neces- 

 sary. 



Mr. Oardbw criticises my proposal to convey the water 

 from the Cataract Reservoir to Sydney through pressure 

 tunnels, in which he differs from me in the size of the 

 tunnels, the method of excavation and lining, and the total 

 cost of the work. I do not wonder at it, for the compu- 

 tations are, as he also found, very complex and difficult. 

 I may say, however, that I gave the whole matter a great 

 deal of study, and am still of opinion that my results will 

 ultimately be found to be not far out. 



I may say that I recognised the loss of head which would 

 result by connecting several small rising mains with the 

 shafts at Ryde and Grown Street, and so made the branch 

 tunnels large enough to convey the whole supply of 75 

 millions each to Wahroonga and Waverley respectively. If 

 therefore, any difficulty should arise in the future, it would 

 only be necessary to extend the tunnels to Wahroonga and 

 Waverley, and convey the water up shafts at each place 

 to reticulate the whole supply from there instead of from 

 the lower levels at Ryde or Crown Street. This of course 

 would add to the cost, but not materially. With reference 

 to the question of excavating the tunnels, Mr. Cardew 

 said "Mr. Keele's estimate is based on the excavation 



