AUCKLAND WATER SUPPLY.

New Zealand Herald, Volume VIII, Issue 2468, 22 December 1871, Page 3

AUCKLAND WATER SUPPLY.

To the Editor of the ITbrat.i.' Sxe, —"With reference to Mr. Cheal's iv'"' er ' which appeared in your issue of yesterday, requesting further information respecting the plan that I purpose for supplying Auckland with water from well 3 and borings, I have much pleasure in complying ivitli his request, j and in furnishing particulars as to the plan, as well as an estimate as to the cost of the reservoir, machinery, building, and pipes required. The plan which I purpose is to sink two or more wells, with collecting tunnels and deep bore holes in their bottom, to intercept the springs which are known to exist in that part ot the G-overnment Domain immediately above Mr. Brighton's garden, and to erect two steam pumping engines of 55 h.p. each, of the most approved construction, and with all the latest improvements for raising water, and for economising fuel; and by means of these engines to puir.p the water into a high service reservoir to be constructed on the highest point of the Domain, which from observations I taken roughly by one with an Ancivid barometer, gives an elevation of 24G feet above high-watc mark, and about SO feet above the water in the present pouds. By this means the inhabitants of Auckland will have the inestimable advantage of an abundant and constant supply of pure spring uuter, delivered from such ail elevation, or with such a pressure in the pipes as will overtop the summits of the highest house in Auckland;— and with regard to the probable quantity to be obtained in this mauner, it is well known that at Mr. Seccombe's brewery, j which is at no great distance from the pro- t posed site of the wells, there is an inexhaustible < supply of the purest water, and the same ( springs will unquestionably be tapped in the i wells, tunnels, aud borings proposed at a some- * what lower lev«l.

I beliove that the present population of Auckland and the suburbs of Parnell, Newmarket, Newton, Bemuera, &c, does liofc exceed 30,000, but I have assumed a population of 40,000, and I allow for this number the

large quantity of 25 gallons pev day, being one million of gallons to bo raised daily by the engines, although this quantity will not probably be required for some years to come. And with regard to the engine power, althou"h one engiuo of 55 h.p. would bo able to raise this quantity of water daily (in 24 hours) to a height of 160 feet, I have provided for two engines of 55 h.p. each, in order to guard against any possible accident or contingency. The project, of supplying a town from deep wells and borings is by no means a new or original one, as it is well known that many large towns in England have been supplied in this manner. Thus Liverpool, with its large population, was supplied for many years froTn seven wells, all situated within the area of a circle of three miles radius from the centre of the town, and the average yield of these wells was about six millions of gullons a day. Many other examples of towns in Kngland supplied from wells might bo given, such, us Manchester, which was formerly supplied from deep wells, one of which yielded inoru than a million of

gallons a day ; Nottingham, supplied partly by water pumped from the Trent, and partly from wells in the red sandstone, water nevedeficient; Northallerion, supplied from shallow wells in the drift, seldom more than 12 ft.

in depth ; Coventry, supplied from springs, and three wells iu the red sandstone; Wells, supplied from wells and springs in tho detrital gravel on which the town is built, and on this subject, Mr. Stephenson, in his second report on the supply of spring water from wells at Watford, mentions the fact of the extraordi-

•:iary yield of the lover bed of the permian series of roolis in the county of Durham, and srates that from two shafts sunk within a few yurds of each other, the incredible quantity of fourteen millions of gallons a day lias been pumped up from the stratum of sand which crosses them. These facts are stated in order to dispel any doubt that might be entertained as to the sutlicieney of the supply from wells ; and with the absolute cost of raising one million of gallons per day from a depth of 170 feet from ono of the Liverpool welis, Mr. Stephenson thus estimates it- : — Fur current expenses, including superintctutance ... ... ... £1,100 Depreciation upon engines and machinery, engine houses, and cooling ponds, £11,200 at 2 per cent. ... 224 Total £1,32-1 It may safely bo assumed that on tho constant supply system by gravitation works, herein proposed for the supply of Auckland—a system which ij always to be'pivferred to Unit of pumping into the mains, — the total current expenditure for working expenses, including, L-oal, tallow, oil, hemp and yarn for packing, and engincmeuand firemen's wugea, witli superiiitcncience, should not exceed the sum of £1,500 per annum, for raising one million of gallons per day from 170 to 200 feet high. The estimate which I havo made provides for two double-power expansive and condensing steam-pumping engines of 55 h.p. each, with all the latest improvements for raising water, and for economising fuel. The price of these is estimated at £6,1X10. Engine house and boiler-houso, chimney shaft and pump-well £2,500 House for engineer and cottages for workmen ... ... ... ... 1,500 High service reservoir in two parts capable of holding from three to four million of gallons, lined with I)rick in Ctjmciifcj on £i concrete bottom 5,500 Two eight feet wells, ateined in brick, with lateral collecting tunnels, and bore boles at bottom, depth uncertain, say 200 feet ... 2000 Cast iron piping with bared and turned joints : — 3000 yards of 20-inch main piping, 1 inch thick 7,425 3500 ditto, 12 diLto ditto 5,315 ■I'JOO ditto, 9 ditto ditto ... ... 4,900 7000 ditto, 6 ditto 3 inch thick ... 4,125 10,000 ditto, iS ditto ditto 3,744 27,500 yards, or 15 miles 110 yards. Elbows, branches, bends, hydrants, sluice-valves, stop-valves, &c. ... 1000 Laying 27,500 yards of piping, three feet deep, including opening of ground and making good ditto, average at 4s Gd per yard ... 6,187 Total £50.796 Contingencies and extras' at 10 per cent 5,079 Preliminary and engineering espeneea 2000 Total £57,875 It is to be observed that I havo allowed the large sum of £32,696 for pipes, elbows, branches, bonds, hydrants, &c, and for pipe laying. 'Ihe cost of the pipes is estimated at £9 per ton, delivered in Auckland, and with bored and turned joints,—so that a water-tight joint is produced without any stuffing or packing of any kind, a little whiting and tallow only being used to assist the close adhesion of the parts. It is needless to say that the pipes should be subjected to test, and should be calculated to withstand a pressure of at least double that to which they will be subjected. 1 think that I hare given hero sufficient data to show that this plan for supplying Auckland from wells ia perfectly feasible, and that the proposed undertaking is ono which, under proper management, cannot fail to prove a safe and lucrative investment for capital, besides providing for a great and pressing public exigency.—l am, &c, Fkbdk. S. PfirrEKCOitNE, C.T2. High-street, December 19, 1871.