136 On the Water Supply of Sydney. 



not such a favourable one as was generally supposed before levels 

 were obtained. I am aware tbat there is much prejudice existing 

 against the George's River scheme, and it certainly appears at 

 first sight a hazardous and doubtful undertaking, but I will en- 

 deavour to show you it is not really so. 



1st. As to tbe quantity of water availiable, the report states 

 that ' tbe entire area drained by the river is 375 square miles, an 

 amount of surface capable of affording more tban 15 million 

 gallons per day. If only one inch of rain per annum were im- 

 pounded from the whole area, the supply would be abundant in 

 quantity, but doubtful as to quality.' 



2. Before we can convert the lower portion of George's 

 River into a fresh water reservoir or lake, it will be necessary to 

 construct a watertight dam. On this point the report states : — 

 1 But the weakest feature in this (the George's River) scheme is 

 the dam across the estuary. If this were made thoroughly sound 

 and efficient by masonry, its cost would be too great ; and if of 

 loose material, as proposed by Mr. Holt, we doubt if it could be 

 made to answer the purpose intended ; at all events, we cannot 

 recommend such a work.' As regards the site of the dam, I con- 

 eider the one proposed between Kangaroo Point and the ' Bald- 

 faced Stag ' the best, because it is not only much shorter than 

 the one at the mouth of the river, but is also protected by the 

 hill called the Bald-faced Stag (see diagram), upon which the 

 flood waters will expend their force, and become almost quiescent 

 before passing over the waste weir, which is about 40 per cent, 

 wider than the river where intercepted by the dam, being more 

 than 25 chains wide ; and as the proposed surface of reservoir is 

 only 8 feet above low water, the impounded water would only 

 rise about 2 feet higher than the highest or spring tides ; the 

 pressure on both sides of the dam would be therefore nearly 

 equal. The waste weir is also sufficiently wide to take off flood 

 waters without their rising much higher than they have hitherto 

 done during former well known floods. The site of the proposed 

 waste weir, like the hills at both ends of the dam, is of massive 

 solid sandstone ; it would therefore bear any amount of scour 

 with impunity ; but this being a sluggish river, the rush of water 

 would not be rapid. 



"While engineer of the Australian Paper Company, in 1865, I 

 ascertained the highest known flood level (of 1860), near the 

 dam at Liverpool, to be 32 feet above high water of spring tides 

 as per railway levels, but as the sectional area between the banks 

 is very limited, the rise would be rapid until it flowed over the 

 banks, which it did in the flood alluded to ; when having a wide 

 field and twenty miles of an expanding river bed upon which to 

 find its level, it always does so before reaching Kangaroo Point, 

 where the appearance of the largest floods have been described to 



