SYDNEY WATEE SUPPLY BY GEATITATION. 49 



to sLut off that source of supply, excepting for the commonest of 

 purposes — such as for mill uses and the watering of the streets. 



Let us now consider the few works under my scheme separately. 

 And first as to the means of great storages, and of leading the 

 extra waters into the one large reservoir on the Loddon. The 

 open aqueduct would be run to the back of Wonona, or say six 

 miles (for present times) from the Loddon swamps and reservoir. 

 I propose that such aqueduct should be cut 10 feet deep, 6 feet 

 wide, and tapered down in the sandstone rock to 1 foot width 

 at the base. The expense of this would be nothing formidable 

 as a national work, even at present prices of labour, and it would 

 be calculated at so much per cubic yard. 



Secondly comes the great Loddon dam, in solid concrete, to be 

 made, by my proposal, precisely in the manner adopted by the 

 famous engineer Mr. Eitter, in his splendid waterworks at 

 Freiburg in Switzerland. The spot I have selected as the 

 position for this work is admirably adapted for such an opera- 

 tion. The gorge of the valley that constitutes the natural egress 

 for the waters of the great basin above is so narrow here that 

 it is only eight chains in width across the rivulet "at an elevation 

 of 30 feet ; but in order to store far more water than would 

 be obtained by a 80 feet high dam, I have marked it off to 

 the top level of the abutting ridge, which would make the dam 

 46 feet over midstream, and where the waters run over a 

 plateau of bare sandstone rocks admirably adapted for sinking 

 a deep concrete foundation. Consequently, to carry the top 

 level of this dam for these extra 16 feet, it would be necessary to 

 elongate the whole work from end to end to 18 chains to where 

 the levels on both sides would taper off to nothing. 



The object I have in view for proposing to raise this dam so 

 high and to be in solid concrete is — first, to be able to turn the 

 overflow flood waters over the side of the eastern ridge into a 

 hollow that leads into another creek, and thus save the risk of 

 damage by the flood waters going over the dam itself. Secondly, 

 to gain immense additional catchment waters, which would create 

 an artificial lake, at a cost which would pay for covering with 

 deep water from 1,200 to 1,400 acres of country free from timber, 

 and which lake would be at the mean depth of 22 feet. This 

 lake would be about 1,120 feet over the sea. 



With regard to the expense of this most important structure, 

 I have one practical guide only, and that is the work of a similar 

 nature built at Freiburg. That dam is 509 feet long and 72 feet 

 high, whereas the one I propose would be only 46 feet high 

 (plus the sinking and erections for a perfect foundation), but 

 proportionately so much longer that it would probably contain 

 about the same number of cubic yards of work, and which at 

 Freiburg is 83,714 cubic yards. The expense of that concrete dam 



