PLAINS WATER SUPPLY.

Hauraki Plains Gazette, Volume XXXIII, Issue 4434, 30 June 1922, Page 1

PLAINS WATER SUPPLY.

PUBLIC WORKS REPORT. ESTIMATED COST £BlO,OOO. A long delayed report on the possibilities of a fresh water supply for the Hauraki Plains made by the Public Works Department over a year ago has at las.t been made public. A copy of the report was sent by Mr. T. W. Rhodes, M.P., to Cr. C. W. Parfitt, who recently asked the Minister to make it public. Cr. Parfitt submitted it to a special meeting of the Hauraki Plains. County Council at. Ngatea oji Wednesday. Mr. T. W., Rhodes, M.P., in forwarding a copy of the report to Cr. Parfitt, stated: “The scheme seems a good one to provide an efficient supply, and the only pity is that the cost is so great. Probably there will be a big drop in the price of< pipes and other material at a not very distant period' which would have the effect of materially reducing the cost of the undertaking." The report, dated June 20, 1921, stated: The,area Ojf the Hauraki Plains requiring to be dealt .with under the scheriie amounts to approximately 120,000 acres. About 67,000 acres of this now requires water, and the. balance of 53,000 acres may not require a supply until about 1930. This depends on the rapidity with which this latter area is made available for settlement.

Thio country will carry about a cow to the acre and a population of about 10,000 when all settled. The totaldaily consumption to be provided for would, therefore, be as follows: 120,00' cattle at 12gal‘ per day — -- 1,440,000 10,000 inhabitants at 35gal, per day — 350,000 Total 1,790,000 The daily quantity for cattle is based bn the army allowance for a milch cow, eight gallons, to which four gallons is added for washing milk cans, etc. The late Mr. Metcalf, of Auckland, gauged the various streams pn the east side of the Waihou between Thames and Paeroa with the following results : (a) Puriri Creek, water unfit for domestic use, as it. is impregnated with iron. (b) Oma.hu Creek, minimum flow 240,000 gallons per day. (c) Hikutaia Stream, minimum flow 800,000 gallons per day. Mining operations are in progress in this valley near the point of intake, sp that this stream cannot be considered.

The only remaining streams likely to prove Suitable are the’ Waitawheta, and its main tributary ,the Manga- ' kino, which, were gauged on March 9 last, after a protracted spell of dry weather of about three months, Theft

results were as follows: Mangakinp Stream, 500,000 gallons per day. Waitawheta Stream, above the confluence of the Mangakino, 10,000,000 gallons per day.

There is a suitable site for a dam about a mile below the junction of these two streams, and a minimum flow of 10,000,000 gallons in very dry seasons may safely be expected. The catchment area above the dapi is about 11,500 acres, which gives a daily run off of about 870 gallons per .acre. A §mall dam sufficient to run the water into pipes would be necessary, and the level of the intake would be about 325 feet about the general level of the country in the Hauraki* Plains. The size of mains allowed for in the report as received from the Paeroa offipe was based on a draw-off distributed evenly over the 24 hours. As the main draw-off will be during .about 12 hpurs amendments have been made to allpw for that rate and the size ofj the plains have been increased correspondingly. A sketch-print-is attached to show how the water has been allotted throngh, the district. Possibly 700,000 ; gallons through the northern branch instead of 800,000, and 1,100,000 through the western branch instead of 1,000,000 may be nearer the future distribution, if all. the present unsettle! area carries an equally dense population, but this will only mean reducing the larger secondary mains on the north branch, about an inch and correspondingly increasing the 15in main bn the west branch, so that the probable total cost will not be materially affected. A 22in main has been allowed for from the reservoir to a point about three miles west of Paeroa. Thence one secondary main leads tow.ards Waitakaruru and the othei- crosses the Plains towards Patetonga. The estimate shows the cost to supply the already settled portion of the Plains to be £610,000, and the probable cost to supply the portion not yet cut up £200,000, making a grand total of. £BlO,OOO. This allows for 120,000 acres, and the annual cost will be: !> per cent interest on £BlO,OO0 —. ; £40,50'0.

V/s Per cent as sinking fund — £12,150. This works out at an annual rate . of 8s 9d per acre, or eliminating the j value of the land at £3O per acre, a > rate of 3%d in the £. i The late Mr Metcalfe estimated the | cost of supplying water to 40,000 I acres at £75,735, but the cost of pipes j is now about three times the them ; cost. I

No allowance is made for service ; pipes or service connections, water I .meters, etc., at the various fahms. — A), j. Baker, District engineer. j Considering of the report was deterred to a later meeting,