100 WATER SL'IMMA TO SYO.NKV BI U li.Y\ ITATION. 



to increase the Bupply by raising the one large dam 20 feet 

 higher, and by extending the south aqueduct to lead more waters 

 1o the tunnel mouth. 



Before entering into the details of my survey for the large 

 impoundage of waters at this place, 1 desire to say that this pro- 

 posed large storage would not be the source at all of the ordinary 

 supply for Sydney, but would be only supplementary by way of 

 a standby in times of drought. I wish it, therefore, in the out- 

 set to be borne in mind that, by my scheme I propose, in 

 ordinary seasons, to supply all wants of the city by the regular 

 flow of the waters planned to be conducted through the Loddon 

 tunnel, which w r ould have its incessant supplies given to it by all 

 the head sources of the Cataract Eiver south of the tunnel mouth ; 

 by the overflow waters of the proposed Loddon Lake, supplied 

 by four permanently running creeks, to be discharged into the 

 tunnel inlet just below the great dam ; by the regular flow of the 

 head sources of George's Eiver, known as Madden's Creek, which 

 would be conducted into the Loddon tunnel by a shaft of GO or 

 70 feet ; and by the overflow of the proposed smaller dam, on one 

 of the heads of the Woronora River, into the open canal beyond 

 the exit of the tunnel waters. All these waters to be led on to 

 the high gravitation iron mains, which would be situated at 1,062 

 feet above the sea, and about 28 miles from Sydney. By this 

 delivery of waters, any excess of supply from such aqueducts, 

 tunnel, and canal, could pass on down the falls of the Port Hacking 

 Eiver, there to subsidize, if required, an additional low-level 

 scheme, which might alone give a suflicient daily supply in all 

 seasons for Sydney, by the adoption of my proposals as shown 

 in my last paper read before this Society, and as shown by my 

 map now lithographed and laid before you on this occasion. 



rurther, I would desire to say that, by my plan of making the 

 aqueduct high enough up to cause the waters to flow into the 

 proposed tunnel-mouth at 1,120 feet over the sea, we can intercept 

 nearly all the Cataract waters from going down their present 

 natural course ; and that in dry seasons we should, in such cases, 

 see that the daily delivery through the tunnel alone would prob- 

 ably be greater than the gauging of the Cataract Eiver at its low- 

 est levels would show, inasmuch as in such seasons the head springs 

 continue to flow freely long after the waters have ceased to flow 

 down the main Cataract gorges into the Nepean Eiver ; and my 

 late surveys on the west slopes of the Bulli, Wonona, and Mount 

 Kiera mountains all go to show that the great supply sources 

 come from the swamps, which are mainly at an elevation of 1,200 

 feet, or above the level of my proposed aqueduct or channel from 

 the south. 



I wish to repeat here the remarks which I made in my former 

 paper on this subject of water supply, — that my single proposed 



