BOROUGH WATER

Greymouth Evening Star, 30 January 1926, Page 8

BOROUGH WATER

MR. e: M. WILLIAMS’ REPORT

As a. result of his special investigation of the Greymouth Borough water supply, made recently, the . exEngineer (Mr. E?M. Williams) submitted the following report to the Borough Council on Thursday evening:— “As per instructions of the Sth instant,. I have carried out a thorough examination of the whole of the pumping plant and reticulation of the water supply of Greymouth and have the honour to report as follows: When I commenced, the pumping plant was working the three shifts continuously and'the level of the water in the reservoir was falling at the rate of 4 inches pef-day. My first consideration was to find the amount of water delivered by the pumps into the reservoir. This was ascertained by closing the town supply off at the reservoir and noting the rise of the water for a given period. The capacity of the pumps was found to be 19,250 gallons per hour. As this indicated a very poor efficiency (59 per cent.) the possibility of the reservoir leaking was next investigated. This was effected by closing the town supply off at

reservoir and stopping ■ the pumping plant for a period. The level of the water was carefully noted before and after a given period. As the level remained constant throughout the test, the reservoir was proved to be watertight and the capacity of pumps as found by the first test to be correct. As this volume of water was in excess of what should be the normal consumption of the town an examination of the mains was commenced. The length from reservoir to Cobden bridge'was tested by closing the valve at bridge and stopping the pumping plant and noting the level of water in the reservoir. The level of water remaining constant proved that no leakage existed in this length. The length from Cobden bridge along Mawhera Quay to Boundary Street was next tested in a similar manner and found to be tight. By eliminating the above lengths, the leakage was confined to the town proper. The tests were next carried on from the Town Hall. The

pi essure uh me gciuge m mts mugineer’s office was noted and the whole of the town south of Murray Street closed off. A fiae in pressure consistent with the ordinary wastage only, being recorded, still further confined the area to be tested. Preston Road and Blaketown were next tested in a similar manner and found to be tight. Alexander Terrace, Alexander Street, Whall and Chapel Streets, were next closed off and a distinct rise in pressure recorded. On a careful investigation being made with presure gauge and stethoscope, indications of a leak were found at the intersection 'of Richmond Quay and Johnston Streets. On opening up the main a serious leak was-found in the tee from the 6in main in Richmond Quay to the 4in in Johnston Street. The valve seat cover of a hydrant was also found to be leaking. These two leaks were repaired and the pressure throughout the town showed a vast improvement. Similar general tests from the Engineer’s office on the other portions of the town did not show any waste or leakage. A test of every Hydrant sluice valve and main in the reticulation was next carried out. Blaketown and Preston Road being excluded from the above as they were found by the general test to be perfectly tight. A large number of leaks were located principally in services. Several suspicious localities were investigated by opening up the mains blit the leakage was found to be in the houses or business services. There is undoubtedly excess wastage of water occurring in the town but the locating of this wastage calls more for a house to house inspection rather than a general test such.as I have carried out. In the meantime, I carefully examined the pumping plant and found some of the valves on the pumps to be defective and the suction pipes from well in need of cleaning. The engineer-in-charge informed me

that he was waiting for a suitable opportunity to carry out the , above work. The pumps were overhauled as directed and are now in fair order. A test carried out- from 12 to 2 a.m. this day showed a delivery of water from pumps to reservoir of 24,800 gallons per hour. This amount equals, an efficiency of 76 per cenC as against. 59 per cent when the first*test was made. The type of pumps at present installed in the pumping station requires careful and daily inspection to maintain the above efficiency. At no time should the efficiency be allowed to fall below 70 per cent. As the hours worked are in inverse ratio to the efficiency of the pumping plant the necessity of maintaining a high efficiency will be appreciated. The difference in the above efficiencies will be better understood'from the following. Given that the pumps required to work 16 hours per day to maintain the demand of the town with the efficiency of 59

per cent. With an efficiency of 76 per cent, working the same number of hours, in 9 days the pumps would have delivered just on 800,000, gallons more water, which is equivalent to the whole reservoir full, every 9 days. The efficiency can be ascertained at any time by closing the town off for 2 hours and carefully measuring the amount of water delivered into the reservoir. It would be advisable to have a house to house inspection carried out immediately as there is an abnormal wastage of water right throughout the town. As the work is more than one man could hope to carry out, I would suggest that the turncock have an assistant until the whole town was inspected. The maximum pressure available at the lire brigade station is 110 pounds per square inch. After midnight and before 5 a.m. a pressure of 100 pounds is recorded. This shows a loss of ten pounds, which allowing for the water used at the Gas Works, Hospitals, Bakeries, etc., is fairly satisfactory.”