46 8TD1TET WATEE STJPPLT BY GBAVITATION. 



further of the grand north-westerly dip of the long coast range 

 to the south and south-east of the Loddon Swamps. As the 

 advantageous dip of 40 to 41 feet to the mile from south to north 

 gives us a complete command of draining the upper parts of the 

 western slopes of that range, therefore we should adopt this 

 gift of Nature to our own uses, and cut a deep and narrow aque- 

 duct through the sandstone country along such range, by such 

 gradients as may be deemed to be most compatible for quick 

 delivery, and to cut such canal as far as may be expedient for the 

 additional requirements. That aqueduct would intercept all the 

 head waters of the Cataract Eiver, and further on, in times to 

 come, and by the aid of a comparatively short tunnel, all the 

 head waters of the Cordeaux could also be led through the Loddon 

 tunnel, and onwards by high and low delivery mains into Sydney. 



In my proposal to cut the aqueduct deep and narrow, I wish it 

 to be understood that my object in this is to intersect as much of 

 the north-westerly stratifications of the range as possible, so as to 

 open out as many fissures of the sandstone formation as may be 

 made available to give off into the aqueduct a large supply of 

 pure water. To this supply too would be added all that we 

 should obtain into such aqueduct from the swamps and tributary 

 streams of the Cataract Eiver that would be coming down the 

 high range from above the level of the aqueduct, and which aqueduct 

 we should throughout its course so contrive to keep up high 

 enough to keep it clear of the broken gullies and deeply furrowed 

 watercourses. 



Besides the above additional resources for water, I would pro- 

 pose to make dams along the topside of this aqueduct, wherever 

 the features of the country about th'e swamps and sources of 

 streams admitted favourably of such action. All such sup- 

 plementary dams could be lowered by their respective sluices 

 into the canal, whenever there might seem to be any occasion for 

 their adoption to keep the one great Loddon reservoir constantly 

 full and overflowing ; and thereby reduce the surface evaporation 

 in diy seasons as much as possible.* 



By such measures for the upper water supplies, I think I show, 

 here alone, ways and means of providing the purest of waters in 

 excessive quantities for all seasons, for a future population in 

 Sydney that may number more than 1,000,000 people. But 

 again, and in addition to all the above-named sources, com- 

 prising constantly running streams, and storage supplies of 

 probably some 3,000 acres of deep water, averaging about 15 

 feet from its mean depth, I propose to have another immense 

 storage supply in the Port Hacking Eiver itself, by means of 

 having another large concrete dam, to be erected at a well-suited 

 spot on the river where the level of the waters is 149 feet above 

 high-water spring tides, and where the features of the covmtry 



* See note at page 56. 



