ORONGORONGO MAIN

Dominion, Volume 20, Issue 46, 18 November 1926, Page 10

ORONGORONGO MAIN

LAST SECTIONS TESTED INCREASED PRESSURE WITHSTOOD During the past ten days the last sections of the new Orongorongo water main have been tested out under the normal pressure (about 340 lb. to the square inch) ■ without any mishap occurring. After the ordinary test it is the usual thing to apply a still higher test than that obtainable with the flow from the intake at Orongorongo (which is 708 feet above the level of the sea). This has been made possible by the laying of a six-inch pipe up the hill on George’s Creek (a stream that runs from the western side of the Orongorongo range into the Morton, dam at Wainui). By following the stream the engineers were able to lay their pipes uphill for another 400 feet, which makes the intake point about 1108 feet above sea-level, and adds another 1251 b. per square inch to the pressure, making in all a pressure of about 4701 b. tq the square inch. Thif pressure was applied to the main yesterday with entirely satisfactory results.

The arrangement of valves and pipes at the lower dam at Karori, in connection with the new main, is interesting. There is at the tower house, whichj projects out into the dam, the main outlet for the new 21-inch main from Orongorongo, but that is not its only outlet. If at any time in the late summer or autumn it becomes necessary to supplement the supply of water in the top dam at Karori, the flow from the main outlet may be shut off and diverted into an 8-inch pipe, which feeds the upper dam; or it mav, bv the .manipulation of the valves, be diverted into the 10-inch main that feeds Northland and Kelburn, where the pressure is sure to be improved-. Still .another alternative remains in a diversion that connects with a 12-inch main that runs from the dam to Aro Street, and so into the general mains of the city.