Upgrading Twizel's water supply at its current source could cost more than $3.6 million.
Opus Consultants has compiled a report which the Mackenzie District Council will discuss today.
The report recommends the council upgrade Twizel's water supply at its existing location at an estimated capital cost of $3.63m plus GST. It suggested this was the most affordable method of meeting the Government's new drinking water quality standards.
Mackenzie district asset manager Bernie Haar said it had previously attempted to find a suitable new source at the Ben Ohau reservoir, but it was unsuccessful in its two exploratory drilling attempts costing more than $80,000.
"One didn't produce enough water, the other didn't produce the right quality. It was disappointing, and it became obvious we needed to return to the drawing board and go back to the current source," he said.
The existing well field is an infiltration gallery on the Fraser Stream.
Mr Haar said the current source had been effective over its 40-year lifespan.
Last year, the council received consents to take water from the Fraser Stream source for another 35 years.
"The councillors will have to grapple with a few issues if they go ahead and decide to upgrade the water supply at its current point, rather than seek out a new source," Mr Haar said. "Twizel is a growing township. This is why a brand new source was initially considered the best option."
However, Mr Haar said installing a water supply at an alternative location could cost about $6m.
The Opus report estimated Twizel's demand for water could increase from an average of 2900 cubic metres per second a day to 4400 cumecs within the next 30 years.
The report estimated it could cost the council another $150,000 to investigate and test a new source "sufficiently to be reasonably confident that the quantity and quality were satisfactory".
Mr Haar said as the council needed to complete a public health management plan by July, it hoped to at least have drawn up plans for the project within the next few months.
"We hope to have an improved water supply, either at the current source or somewhere else, by 2016."
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