GooDALL. — Water' Supj^l'l/ Jot Auckland. 39 



provided always that experiments have satisfactorily proved them to be avail- 

 able ; tlie cheapness with Avhich they can be utilised, being ^:o close to the 

 proposed reservoir, and the waters being so pure, there will be no necessity for 

 settling-tanks or filters. 



Having shown that Mount Eden contains a large cpiantity of water, and 

 sketched a scheme whereby the same might be proved and rendered available 

 for supplying Auckland, I will now make a few remarks as to its sufaciency 

 and probable cost. 



Supposing that the basin under Mount Eden would draw its supply of 

 water from an area of about five scpiare miles, and accepting twenty-four 

 inches of rainfall as available, it will give the large yield of four million 

 five hundred thousand gallons per day ; or, reducing the yield to one-fourth 

 of that quantity to allow for any over-estimate of the area of the gathering 

 ground — it being impossible at present, without boring and other investiga- 

 tions, to determine the exact area of supply — there would still be left over one 

 million gallons per day, which would be more than sufficient to supply 

 thirty-three thousand inhabitants with thirty gallons daily j)er head. These 

 results depend entirely upon the depth and circumference of the basin, which, 

 when ascertained, will give reliable data. 



It seems natural that by pumping at the centre of such a supply, before it 

 had time to distribute itself, the full amount of i-ainfall percolating through 

 the gathering area maybe i-aised, and a larger quantity could be obtained than 

 from a similar area at the Western Springs, or from those at Onehunga, where 

 only comparatively small quantities flowing in particular directions can be 

 nsed, the natural outlets being numerous. 



The cost of such a scheme would be less than one from Onehunga or from 

 the Western Springs, as not only would a great saving be effected in transit 

 pipes, but also in cost of pumping, as the water might be obtained at a 

 considerably higher level than at either of the above-mentioned places. By 

 examining the level of the outflow of the water at the Western Springs and the 

 water standing in a well sunk by Mr Edgecombe — the distance between these 

 two places being about a quarter of a mile — it will be found that the latter 

 level is twenty feet above the former, which would give a rise to the 

 centre of Mount Eden of about one hundred feet. This evidence is further 

 corroborated by the large quantity of water obtained at a high level in the 

 well of the Northern Brewery, on the Ivyber Pass Road. 



The height to which the water would have to be lifted would be mider two 

 hundred feet, to a reservoir at Gilfillan's corner, whicli point is ncai'ly three 

 hundred feet above the sea level. 



The cost of plant capable of raising a million gallons daily will be as 

 follows .• — 



