Hydrologist challenges upgrade plan

East Otago still faces the prospect of running out of water in extreme dry years, an issue which does not appear to have been addressed by the Waitaki District Council, according to Dunedin hydrologist David Stewart.

The council is considering dropping a plan for a $28 million pipeline which would have taken water from the Oamaru water treatment plant as far south of Palmerston.

The plan was a solution to meeting new drinking water standards and to provide a security of water supply.

The council now has a $7 million proposal to upgrade individual water supplies.

But Mr Stewart said yesterday that did not address the issue of water schemes serving Palmerston, Dunback and Goodwood running out of water in extreme dry years in the Shag River catchment.

In 1999, the council had to truck water to Palmerston and was only one day away from sending a train of tankers with water by rail.

The council has carried out a study of 10 community water supplies south of Oamaru.

In relation to Palmerston-Dunback-Goodwood, within close proximity of each other, the study proposes combining their resource consents and one water treatment plant to meet the new standards.

It estimates the current demand of the three schemes at 1381 cubic metres of water a day, with resource consents totalling 1500cu m a day.

Future demand has been estimated at 1561cu m a day.

The extra water needed, the study suggests, could come from the small Blue Mountain supply on a Shag River tributary, which serves two properties and is underutilised.

But Mr Stewart said having the resource consents which met demand did not mean the water was available in extreme dry years, like 1999.

He was involved in two extensive studies into all the water resources of the area funded by residents, the Government and the council.

The Shag River catchment was "water-short" - the Otago Regional Council was not issuing new consents to take water, he said.

"There does not appear to be any interest or consideration given to one of the problems that the pipeline was going to address - that there is not enough water," Mr Stewart said.

If demand is forecast to increase and there was "another 1999", the problem would be worse if water was not brought into the area from somewhere else.

"The only option the council has is to make sure the existing consents can be fully utilised.

"However, if there is not enough water, like there was in 1999, then the consents don't guarantee the water will be there."