BOROUGH WATER SUPPLY.

Wairarapa Age, Volume XXIX, Issue 8310, 13 December 1906, Page 7

BOROUGH WATER SUPPLY.

ENGINEER'S REPORT. As requested by the Masterton Borough Council, the Engineer submitted a report to the meeting on Tuesday night on the water supply •of the borough. The report stated, inter alia:— " The supply from the head-works originally included two intakes —No. 1 being called the lower intake, and being a creek which embouches from the shingle on the Waipqua river flat at the bottom of Mr Falconer's property, and re-joins or forms a confluence with the Waingawa river a few chains below the No. 1 intake. This creek was estimated in November, 1897, to deliver 2,200 gallons per minute, and it was assumed that the dry weather flow would not fall below one-third of this amount. The creek is about one and a-half to two miles in length. To conserve the water of this creek, a dam was erected below the feeding gallery of the same, and had the. effect of penning .up this water, which, when not largely drawn upon, became stale, as no by-path or means of letting off such pond ever existed. The poor quality of this water led in December, 1905, to the abandoning of this creek as a source of supply, and the dam has been destroyed and the creek allowed to . flow into the Waingawa river. No. v 2 intake, although lowest or nearest to town, is called in tho original report " a spring 12 chains beloAV the lower intake." It was estimated to discharge 600 gallons per minute in 1897, and probably does so during many months of the year. On several occasions this spring has fallen off by more than one-half of the said supply. No. 3 intake was only made at the end of last year. As the source of this supply is an underground one, I have no guagings at present of the amount supplied. In the original report it appears to be assumed that the minimum supply from the No. 1 and 2 intakes would be about one and a quarter 'million gallons per day, and a maximum of nearly four millions. I find, however, that the maximum capacity of discharge into the reservoir is at the rate of about eight and a half gallons per second, or say 700,000 per twenty-four hours, whilst when the springs are not at the maximum there is a corresponding decrease—from this it will be seen that the capacity of the present intake pipe should have been larger; - The, present reservoir, 115 ft long by 50ft 'wide, gives a storage capacity of about 200,000 gallons, but will have to be increased at some future time. The* trunk main into towil is 10-inch diameter, giving a hydrostatic pressure of 97lbs, and should when new have been capable of discharging over one and a quarter million gallons per twenty-four hours into town. It is more than probable that this capacity has been reduced by the disappearance of the patent pitch' coating

which was used on the pipes, and by the formation of iron nodules or "rust , excresences on the inside of the pipes in lieu thereof. I am of opinion that several valves should have been placed on this line The ' reticulation of the borough comprises 6-inch pipes in Queen Street, parts of Dixon' and Chapel Streets, and Lincoln Road to Bentley Street; the other parts of the borough where supplied i have 4-inch, and l|-inch pipes. This for a domestic supply would of course give an ample distribution, but owing to the excessive use of water for gardens, the pressure ,» available is reduced in dry weather generally to about 651bs, and occasionally less. With a view to testing ; the capacity of the system from a. fire point; of view, Captain Jenkins was kind enough to make a number of tests > for me. The pressure varied fr6m TSlbs before the test to 40lbs during the test. Tests of volume of discharge were made by the turncock on the same day as the ■ water test by taking the time which it took to fill the large water cart (670 gallons) by hydrant at various localities., These tests give a clearer insight into the loss of head owing to small pipes than any otner demonstration can, and show the loss of discharge by using small pipes. In the vicinity of the railway station the water available for fire supply is somewhat meagre. With a view to remedying this, the pipes for a new 6-inch main should be in hand in January next for a connection from 'the Upper Plain Road along the new portion of Pownall Street to the end of Villa Street. In regard to the small pressure available for reticulation purposes, it is clearly pointed out in ,the original report that if an • amount of say one and a quarter million gallons were brought into the headwords and distributed to 12,000 or 15,000 people at 70 gallons per head, the hydrostatic pressure would fall to 43lbs. Instead of this, however, at the most only 700,000 gallons can come into the system, and the 1,025 connections now in use are so much drawn upon that the pressure is reduced to about 65 or 70lbs,

and even less at times owing to the excessive consumption of water by • residents. The conclusion to be drawn from the foregoing investigation is that so far as the water supply is concerned there is no great discrepancy from what existed at the start thereof. If a greater efficiency from the present supply is required in -town there are several means by , which it can be obtained, viz :—l. By confining the use of the water to domestic purposes. '2. By providing • bigger reticulation mains within the town. 8. By providing a supply from further tip the Waingawa river with a reservoir at, say, 100 feet higher elevation than the present one."