On the Water Supply of Sydney. 135 



Parliament to erect the proposed dam, but have not as yet suc- 

 ceeded. If Woolli Creek is to be utilised in this supply it may 

 be found advisable to render the present dam watertight by clay 

 puddle or Portland cement beton ; the expense in either case 

 would be about the same. 



Both Cook's River and the lower portions of "Woolli Creek 

 might be greatly improved as reservoirs by dredging, the soil 

 being used for raising the banks where most required. It would 

 be also necessary to pass an Act to prevent the further pollution 

 of these streams. 



If the Botany scheme is adhered to, we shall be able to 

 obtain at least an equal quantity from Cook's River to that now 

 supplied from Botany ; and as it will be about eighteen years 

 before the population of Sydney is doubled (at the present rate 

 of increase), we should have ample time to prepare for the grand 

 supply from George's River. Cook's River, with the Woolli 

 Creek, contains a watershed of twenty-four square miles, or three 

 times that of the Botany Works, but would probably produce 

 only 25 per cent, more water, on account of the wonder fully 

 retentive qualities of the Botany watershed. The two works 

 combined would supply abundance of water for double the pre- 

 sent population of Sydney and its suburbs. This would be bj 

 far the cheapest scheme yet propounded, and the soonest ob- 

 tained, since the water would not require more than two years' 

 rain to make it perfectly fresh, on account of the small amount 

 of water in Cook's River below Canterbury compared with the 

 available rainfall ; the capacity of Cook's River being not more 

 than 1 per cent, of one third the annual rainfall. It might be 

 pumped from Cook's River near Thompson's Bridge, where it is 

 only a mile and a half from the reservoir proposed by the com- 

 missioners in their report, and which they propose to supply with 

 water at a cost of about £650,000 by their low level scheme. As 

 we are liable any year to have a drought, it would not be wise to 

 depend even upon the joint supply of Botany swamps and Cook's 

 River. In 1849 the rainfall was only twenty inches, or less than 

 the average rainfall for the last fifteen years. If a similar 

 drought were again to occur, the joint supply would be reduced 

 to the present supply of four million gallons per diem, and that 

 with an increasing consumption. 



George's River Scheme. — It has been proposed to connect 

 George's River, with Cook's River by an aqueduct, or water race, 

 between Salt Pan Creek and Woolli Creek ; but, on referring to 

 the section in the Government Report of the Water Supply, I 

 find it would be necessary to tunnel for about three miles, and 

 even then to raise the water several feet to get the necessary fall 

 into Cook's River ; in fact, the proposed site of the channel is 



