Report by John Busby

Having directed my attention to the examination of the lagoons nearest Town, I put down several boreholes in each to ascertain the nature of the strata on which they rested. I found a fine and almost impalpable quicksand, from which it would be impossible to separate the water mingled in abundance with it. I was then led to the examination of the large lagoon in the vicinity of the old paper Mill, from which the Waterloo Mills draw part of their supply. This lagoon is lower than the others, and receives water from them by drains made by the Waterloo Company. The water is perfectly transparent and colourless, free from every taste and smell, and so soft as to be fit for washing and every other domestic purpose. It is also so abundant that, when the population much exceeds its present amount, they will here find an adequate supply. It is likewise fortunate that it may be taken for the use of the Town without interfering with the purposes to which it is at present applied; for by an embankment of comparatively small extent, the lagoon may be formed into a reservoir, which, by collecting the surplus water that falls in the wet season, will yield to the Mills in the dry season a quantity equal to that abstracted.

Calculating on the large allowance of a hogshead or 8.5 cubic feet daily for each family (or every five individuals), the quantity required for Sydney, supposing 15,000 inhabitants, will amount to 9,307,500 cubic feet annually. But it is to be observed that, during at least six months of the year, there is more water than the Town and Mills require. It is, therefore, only for the water taken during the remaining months, when the supply is scanty, that any compensation should be made. The quantity will thus be 9,307,500/2 or 4,653,750 cubic feet. To compensate for this abstraction, there will be a reservoir containing at least 100 acres, which may be laid under water to the depth, on an average, of 3 feet, giving 1,306,800 feet, a quantity much exceeding that abstracted. Fron the large average quantity of rain, and the great extent of surface above the level of the reservoir, it may be fairly presumed, that a much greater portion than is here stated may be collected, so that the Mills, instead of being deprived of water at any season, will have it in their power to employ, during the dry season, a greater quantity than they would otherwise have commanded.

About 100 Yards of embankment will be required in the lagoon; and before the foundations of it can be properly laid, it will be necessary to cut a drain to carry off the water during the operations. part of the drain will be in located ground, but it is presumed no objections will be made. I would also beg leave here to observe that, if the Old Paper Mill and the located ground towards the lagoon be procured, the embankment already made may be raised and strengthened so as to afford a fall sufficient to turn a wheel, by which the water may be sent home during the greater part or whole of the year, and the necessity for any other power probably superseded. An additional reservoir would also be thus obtained.

( Extract of a Report by John Busby to Sir Thomas Brisbane dated 28 June 1825 )

Source:

Historical Records of Australia: Series 1; Volume XI ( pp.683-4 ) (The Library Committee of the Commonwealth Parliament, 1916)