AMPLE ARTESIAN WATER AVAILABLE IN BOROUGH

Manawatu Times, Volume LIV, Issue 6893, 26 April 1929, Page 7

AMPLE ARTESIAN WATER AVAILABLE IN BOROUGH

Engineers Recommend That Wells Be Sank FULL TEXT OF REPORT On iiie grounds that there is ample artesian water available •or the present requirements of the borough ,of Palmerston North and that, by an expenditure of £13,610, results comparable with the expenditure of about £45,730 on the gravitation scheme, could be obtained, along with reduced running costs, Messrs. Vickerman and Lancaster, consulting engineers, recommend for the serious consideration of the Palmerston North Borough Council, the adoption of an artesian source for the next extension of the water supply system. The Council will consider the report at a special meeting this morning. The full text of the report is given below.

The question which, we are specially asked to investigate and advise upon is tike relative economy of pumping from artesian wells as compared with increasing the size of the mains from the Tiritea gravitation supply, for the purpose of improving the pressure in the existing system. Present Position. The present supply is obtained byi gravitation from the Tiritea watershed which the reports you have already received show can be made to supply a population of 34,000 with 100 gallons per head per day at a further cost of £147,830. At present tho population is approximately 20,000 and the daily consumption nearly 2 million gallons, equivalent to 100 gallons .per head per day, or an average per hour of 80,000 gallons, the maximum hourly demand being about 87,000 gallons for domestic purposes, or, including water used for cleaning filters, about 97,000, and the demand through the night sinking to between 60,000 and 65,000 gallons per hour. Tho levels of the borough arc such that there is a fall from north to south, thus whilst tho level of the Square is 100 feet abovOi soa, the northern boundary is 155 feot, the hospital and Ruahine street 125 feat and the southern boundary is only about 85 feet. It is therefore at the northern or Terrace End that lack of pressure is most keenly felt. Examination of pressure charts indicates that with a demand of 60,000 gallons per hour a pressure of 751bs. is registered at the hospital and. 1051bs. in the Square; with 65,000 gallons the pressures are 6()lbs. at the hospital and 951bs. at the Square, whilst with 87,000 gallons the hospital pressure drops to lOlbs. and that in tho Square to 501b5., the pressures at other demands being proportional. In the southern portions of the town, as the ground is lower, the pressures approximate and are generally rather better than those in the Square. The existing installation may therefore be considered reasonably satisfactory for demands only up to 65,000 gallons per hour, or about 1.5 million gallons per day.

plies are obtained from. between 370 feet and 470 feot below the surface; that some localities are better than ethers; that the supply of water is somewhat limited in that a new well driven in its neighbourhood may interfere with tho flow from an old well; •that as wells grow older they apparently become choked and their flow decreases. It is quite clear however, that ample artesian water is available for present borough requirements, and experience in other places, where larger size wells have been put down, i 3 that bigger flows can be relied on from these, and that where proper attention 1b paid to fitting perforated suction pipes, and to keeping the well running continuously, these flows are maintained. As regards quality, this appears satisfactory in view of the following extracts from? the report of 25/3/29 by the Dominion analyst on the samples submitted to' him:— “All these waters are of good quality for potable use but somewhat hard for washing, or use in steam boilers. “In the water used for the present supply the figures for oxygen absorbed and albumoid nitrogen are much higher than those of the artesian waters. .The temporary , hardness however, is less. “While, therefore, the artesian waters are of better quality for potable use, the present supply is more satisfactory for use in steam boilers.” ■ i/j .

Proposals for Utilising Artesian Supplies. The utilisation of artesian water is intended to be an adjunct of the present gravitation supply. For the complete accomplishment of tho scheme a ring main for distribution within the borough, much as is proposed under the gravitation scheme, is required, with several pumping stations adjacent, to, and pumping into this, the Tiritea dam and main being utilised for balancing pressures as well as for giving part of the supply." At the present time tho full scheme is not necessary, as 30,000 gallons per hour introduced into the borough independently of the Tiritea main would leave tho latter supplying a maximum of 60,000 to 65,000 gallons hourly with the corresponding pressures of. 751bs. at the hospital and 1051bs, in fihj} Square, which would be quite satisfactory. Based on the flow of 7020 gallons per hour from the 3 inch well at the gasworks, 30,000 gallons per hour should be obtainable from one of 6 inch diameter, and it is suggested that at present one such well should be driven in the neighbourhood pf the hospital, and a pumping station established there delivering into a 9 inch pipe along Euahine street, with a 12 inch connection along Ferguson street into tho Tiritea main, or, preferably into a 9 inch pipe along Euahine street with a 12 inch along Featherston street east, and an 18 inch connection along Eangltikei street to the Tiritqa main. The well should be connected to an underground cistern of about 100,009 gallons capacity, say 20 feot deep by 32 feet diameter, to serve as a sand trap, a fire fighting reserve, and by tipping the well below the ground level to correspondingly increase rts flow. Two electrically operated pumps with automatic electric controls and each of 500 gallons per minute, against 170 feet head capacity, should be installed, one being almost constantly required for domestic supply and tho other to give special temporary supply in the event of an outbreak of fire.

To improve the gravitation supply, proposals, with which we concur, are set out in the second paragraph of Messrs Toogood and Hughes report of April 7, 1924. Those involve spending £42,460 in the first stage, £12,070 in the second, and £93,300 in the final ,or a total of £147,830. The result of these works would be to insure a satisfactory supply of 3.4 million gallons per day. This is an increase of 1.5 millions over that now actually supplied, or of 1.9 millions over that now satisfactorily supplied. Tho present annual cost is stated to be approximately £7,500, in l eluding £4,900 for interest. On the' basis of a daily supply of 1.9 million gallons this is equivalent to 2.6 pence per thousand gallons, or on tho basis of' 1.5 million gallons daily 3.3 pence per thousand gallons. If a further £147,830 bo spent to bring the daily supply up to 3.4 million gallons, the cost for the additional water, allowing 5J per cent, interest and 2 per cent, depreciation on the capital involved, but not charging any additional wages, would bo for 1.5 million gallons 4.85 pence per thousand gallons, or for 1.9 million gallons 3.84 pence per thousand gallons. Artesian Wells. Some 25 artesian wells of from 2 inch to 4 inch diameter are in operation in tho borough and adjoining area, eleven of these, which have been measured, yielding a combined flow of about 88,620 gallons per hour. The best wells are as under:—-

' The Cost. We estimate the cost of such an installation would be as follows: — (a) Connection via Ferguson street — 1 well, 6 inch dia. and tank .. £2OOO 2 automatic motor driven pumps each 500 g.p.m. capacity .. £ISOO Pipes Ruahine and Ferguson streets £6500 Contingencies, and Engineering • 7>} per cent. .... .. .. ..:♦••• £750 £10,750 (b) Connection via' Featherston street—--1 well and tank as above .. .. £2OOO 2 pumps as above £ISOO Pipes Euahine, Featherston and Rangitikei streets £9160 Contingencies and Engineering 7i per cent. ... ... .. .. £950 £13,610 The annual icost involved hy each of

Midland Brewery, 3 inch diameter, 400 feet deep, 6000 .gallons per hour. Gas Works, 3inch diameter, 472 feet deep, 7020 gallons per hour. Massey College, 4 inch diametor, 407 feet deep, 31,440 gallons per hour. Eacecourse, 4 inch diameter, 400 feet deep, 15,900 gallons per hour. Eacecourse, 3 inch diameter, 852 feet deep, 8400 gallons per hour. Unfortunately the history of the older wells, that is with regard to tho amount or their flow when first driven; whether they have since been allowed to flow freely and regularly; whether they have perforated or slotted, suction pipe in the water bearing stratum or merely collect water through the end of the pipe, is unknown. The information available, appears to indicate that the host sup-

the above would be as tabulated be*

The tost per thousand gallons for a satisfactory supply by developing the gravitation scheme is estimated- to range at between 3.3 and 3.84 pence. In this connection it may be noted that the coat of artesian water in Christchurch is 111 peace per thousand gallons. " / From the above it appears to us that the results obtainable by an expenditure of £13,610 on an artesian supply are comparable with those involving about £45,730 on the gravitation scheme and further, that by the artesian scheme the cost of water would bo reduced for present requirements to about 65 per cent, of the present cost, whilst as requirements increase the cost , would ultimately only amount to 40 per cent of what would be possible by gravitation. In these circumstances we strongly recommend to the council for its serious consideration the adoption of an artesian source, as outlined above, for the next extension to the borough water supply system. We have to acknowledge with thanks the full and very well set out information supplied for cur use by the borough engineer, and also his and the town clerk’s assistance to us in making our investigation.

low: — Interest, 51 per cent. .. Depreciation pipes, 2 p.c. Depreciation pump, 5 p.c. Power,' 45 k.v.a. at £8 (a) £591 £130 £75 £360 (b), £749 £183 £76 ■ £360 Attendance, part .time . £150 £150 £1305 £1517 Equivalent to a cost per day of,.. . • £3.68 £4.16 The cost of water for each alternative in pence, per thousand gallons, would then be:— x .(*>, < b ). 1. Assuming 500 gallons ( per minute throughout P , ; ' ■ .or 720,000 gallons 'pet ; t ‘ _ d&y - i*- *• •• *• l.y# v 2. Assuming operating part, time only and gal- 5 ‘ Ions por day . .. .. 2;20 2.49