M STDITET WATEB SUPPLY BY GEAYITATION. 



presence of familiar water plants. This country is unfit for any 

 purpose for man or beast, and is suitable only for its own special 

 and high value as a great gathering ground for supply waters. 

 It is there seemingly and essentially as the great water- sponge 

 and filter whereby Sydney might be supplied to a very large 

 extent in all seasons. My proposed dam being made, the storage 

 of water within such one dam alone would be so enormous that ifc 

 would hold enough water probably to supply Sydney with its 

 present population for more than a whole year. It would be 

 quite as large, if not larger, than the Prospect dam that was 

 proposed to be made in connection with the Upper Nepean 

 scheme ; and as, by my proposed plan, the whole of the water could 

 be drawn out from u.nder the bottom of the dam for transmission 

 below it into the Loddon tunnel, so it would represent the same 

 depth of storage water available for Sydney as the Prospect dam, 

 the upper 25 feet of which would only have been available for 

 gravitation, as admitted. The supply in all seasons off the 

 Madden' s Plains swamps would be more than enough to keep pace 

 "with the evaporation from that reservoir, even if I had no other 

 proposed and available source of supply to keep it up and over- 

 flowing. 



The elevation of the lowest spot of this proposed lake would 

 be at the level of the bottom of the dam, and that would be sufil- 

 ciently high to admit of the whole of its waters being drawn ofi" 

 and conducted by a tunnel of 3 miles and 35 chains, to come 

 out north, at the head source of the Port Hacking Eiver, whilst 

 such flowing waters would have a fall of 4<^ feet to the mile all the 

 way for se^en miles to the intake of my proposed gravitation 

 mains for Sydney direct, from 1,050 feet elevation. 



Besides this large storage of water by this one dam and by its 

 available tributary dams on the south side of Madden's Plains, 

 I found that I could secure between 800 and 900 acres more 

 water on the north side of same plains and on the ever running 

 Madden Creek. This could be most easily and economically 

 effected by the formation of three small dams at suitable sites : 

 the first to be 9 chains wide and 25 feet high, which would give 

 400 acres of water ; the second to be 7 chains wide and 15 feet 

 high, to yield 230 acres of water, and the third to be 9 chains 

 wide and 15 feet high, to give 200 acres of water ; in all here 

 830 acres of extra storeage. All the fine and permanently ruhning 

 water of this creek, together with its own storage waters, could 

 be lowered by means of a sluice into the Loddon tunnel through 

 a shaft of 73 feet — such shaft to be cut out of the solid sand- 

 stone ; and then all these cumulative waters of the Loddon and 

 of the Madden Eiver streams would pass on north-easterly by 

 the tunnel, and on afterwards by the open canal of nearly 4 miles 



