Failure of the Van Yean Reservoir^ 



157 



It also appears that the immense extent of the reservoir, 

 which has always been regarded as its greatest advantage, is 

 in reality so serious an evil as to involve the failure of the 

 whole scheme. 



It is quite clear that the difference between the amount of 

 rain and evaporation will represent the amount of loss depend- 

 ing upon the wide extent of the surface exposed. This 

 difference is six feet, and is equal to nearly twice the whole 

 discharge of the river, as measured by your Committee, above 

 Yan ^ean, and is nearly equal to Mr. Blackburn's estimate 

 of all the tributaries above the swamps. The whole amount 

 thus lost by evaporation in the reservoir, or nine feet, being 

 sufficient to supply a population of 245^500, at the rate of 

 forty gallons per head per day, or 491,000 at twenty gallons, 

 which is equal to a loss of 9,820,000 gallons of water per day. 



With an unlimited supply of water this immense loss would 

 have signified little, but when the sources of supply are so 

 remarkably inadequate, the case presents a very different 

 aspect. 



The foregoing considerations afford no prospect whatever 

 of success to the Yan Yean scheme with the existing sources 

 of supply, but it has always been regarded as capable of inde- 

 finite extension from other sources. It becomes necessary, 

 therefore, to consider this part of the subject, in order to ascer- 

 tain how far it may be possible, or practicable, to supplement 

 the reservoir, and thus render it equal to supply, not only 

 the present wants of the City, but a large prospective increase 

 of population. 



For this purpose it has been proposed to bring the Merri 

 Creek, the Diamond Creek, the King Parrot Creek, and even 

 the Groulburn River itself, into the reservoir. 



With regard to the Goulburn River, if it were practicable 

 to bring it into the reservoir, by means of an aqueduct, and 

 if the expense of such an undertaking would not be beyond 

 the means of the colony, there cannot be a doubt that this 

 would render the Yan Yean scheme eminently successful, and 

 Melbourne might then boast of being better supplied on the 

 gravitation principle than any other city in the world. 



I feel incompetent to give an opinion in a case involving so 

 many difficult questions, and that could only be determined 

 by experienced engineers, after complete surveys of the 

 intermediate country ; but it appears to me, independently of 

 the expense, which would be enormous, to be altogether 

 cliimerical. The great dividing granite ranges, which must 



