Hemarhs on the Report of the Water Commission. 65 



a rnucli less distance of some of the suburbs, without cost, and 

 that the expense of pumping it up will be much less than that of 

 making and maintaining 53 miles of artificial conduit. The whole 

 of this argument rests upon the supposition that the river can be 

 effectively dammed near its mouth and at a moderate cost. If 

 that cannot be done, the whole scheme must be admitted to be a 

 failure ; if it can, it can hardily be denied that it is superior to 

 the "Upper Nepean." Upon this little "if" the whole question 

 turns, as on a pivot. To the possibility therefore, of constructing 

 an efficient dam, let us now turn our attention. 



The cost of a dam across the George's River is estimated by 

 Mr. Moriarty at not less than £650,000. Even if this were a 

 correct estimate, I am not sure that the greater recommendations 

 of this scheme would not justify such an outlay in comparison 

 with the amount required for the Upper Nepean scheme. But 

 then Mr. Moriarty has estimated for a masonry dam, built on the 

 rock bottom, and for a banking up of the river to a height of 

 fourteem feet sis inches above high water at spring tides. But 

 would not this be a wholly unnecessary expenditure ? There 

 would be no necessity, for ttorage purposes, at any rate for a long 

 time to come, to raise the dam or the weir beyond the limits 

 necessary to keep fresh water from going over the former, or salt 

 water over the latter ; and would it be necessary, in order to 

 construct a dam of sufficient retentiveness and solidity, to have 

 artificial masonry, or even to go down to the rock bottom ? The 

 method I suggest is, in the first instance, to construct a break- 

 water of rubble stone, well intermixed and covered with tenacious 

 soil ; and then, on both flanks of this breakwater, to put a thick 

 padding of sand. There is an unlimited supply both of stone, 

 and mud, and sand in the immediate neighbourhood, and the cost 

 of tipping it into position would be comparatively small. 



With respect to a dam so constructed, two questions present 

 themselves for consideration : First, would it stand ? Secondly, 

 would it keep the salt water away from the fresh ? It must be 

 understood that the water is not intended to go over this dam ; 

 on the contrary, the most ample precautions would be taken to 

 prevent such an occurrence. South of Cummins' Point are two 

 dips in the rocky ridge, either of which would furnish an avail- 

 able site far a waste weir. The ground is rock, and would only 

 require to be cut down to a level just sufficient not to allow the 

 highest spring tide to send salt water into the river. The weir 

 could be made of any length required, and ample to allow a free 

 discharge for the water of the river in the heaviest floods. It 

 should be observed that so extensive are the bays in the 

 lower reaches of the Greorge's River that they act as flood- 

 moderators. The consequence is that the heaviest flood makes 



