Top popped on tank

Ruapehu Bulletin, Volume 9, Issue 433, 21 April 1992, Page 3

Top popped on tank

The lid went on Ohakune's new water reservior recently, capping off an important, part of the town's new treatment plant. The tank is a 1500 cu-

bic metre capacity wooden tank, storing enough water to supply Ohakune for one day at peak use rates. The tank, measuring 19 metres in diametrer

and six metres high, was built by Timbertank Enterprises Limited of Kohimarama, headed by architect Morton Jordan, who started building the tanks in 1972.

The building of the tank is something of a coming home, Morton having lived in Ohakune as a boy when his father was the local general practioner. He remembers the wooden tank on the water tower at the Ohakune Railway Junction. There are differences between his tanks and the old railway watering tanks, that may not be obvious to the uninitated, but should please local people as they lead to a structure that can withstand large earthquakes. Unlike the old style water tank, there is no base to the Timbertank. The water is contained inside a synthetic liner, which sits directly on the earth, which is leveled, then shaped and with sand laid down. The liner means there is little or no leakage, unlike the old American style railway tanks, said Mr Jordan. He said the base

structure of the old tanks was difficult to build and leaked "like a sieve". The new tank s treated timber staves, which are held together with prestressed steel cables, sit on a concrete ring base. The design of the structure, with the roof providing much of the strength of the shape, provides a tank which is very good at withstanding earthquakes, said Mr Jordan, which has been proved in the Edgcombe earthquake were timber tanks and large reservoirs survived with no damage at all. With the 'bag of water' sitting directly on the ground it can move backwards and forwards inside the tank, and the tank structure itself moves freely also. The Ohakune reservior is the third of its size Timbertanks have built, and they have built thousands of tanks and reservoirs both in New Zealand and overseas.