Renwick losing 300,000 litres a day

Last updated 07:10, October 15 2015

Nearly 300,000 litres of water is leaking out of Renwick's water supply every day.

A study of the township's water pipes was carried out by contractor Detection Services last week. The company reported 30 underground leaks in total.

Marlborough District Council operations and maintenance engineer Stephen Rooney said almost half the leaks were on the council network, with another 17 located on private property.

It was a "significant waste" and added up to 207 litres a minute, about 15 per cent of Renwick's daily consumption. Four large leaks were each letting out between 30 and 40 litres of water a minute, Rooney said.

The level of corrosion was expected considering the water network was installed in 1974, Rooney said.

The network would eventually become uneconomic to repair, but that point was still 30 to 40 years away, he said.

A council spokeswoman said money for the repairs carried out on council property would come out of the budget for infrastructure maintenance. Owners were responsible for repairs at their own addresses.

Rooney said the council was going to repair all of the leaks in its network over the next two weeks, and was offering each property owner a free 20-minute consultation to help pinpoint the source of their leaks.

Similar work done a year ago found 32 leaks in the network.

None of the leaks were visible from ground level.

"Ideally we'd like property owners to get onto this as soon as possible, as we want to get the whole network into the best possible shape before summer when water supply is again expected to become an issue. It's in everyone's best interests if we're not wasting the water we do have," Rooney said.

Letters would be sent out to property owners next week.

Renwick Smart and Connected chairman John Kelly said finding and fixing leaks was "a step towards a sustainable and steady water supply".

"I think it's really positive," he said.

Water restrictions this year would depend on how well the aquifer recharged over the next few months and how wisely residents used water, Kelly said.

Council scientist Peter Davidson said the monitoring wells at Conder's Bend, near Renwick, were at the lowest since records began in 1982. The aquifer relied on the flow from the Wairau River, which had been very low for months.

Earlier this year there was a three-month ban on watering gardens in Renwick.

The council told Renwick residents on Monday they were likely to face another summer of water restrictions. Rooney said he could not predict the duration or severity of the restrictions.

Residents wasted 70 per cent of water in their garden but if they mulched their plants using compost, pea straw, bark or gravel to seal in moisture, they could cut the amount of watering, he said.

In the Long Term Plan in June the council agreed to budget $11 million for a new water reservoir, water metering, water treatment and water source in Renwick.

The council said it would report on the costs of water metering by the end of the year, and consult with the community next year.

A Renwick resident said he was expecting water restrictions to be imposed earlier than last year, and to last much longer.

The idea of meters had been a "twinkle" in the council's eyes for some time, he said.

"They're not going to change the shortage of water," he said.

Kelly said he believed any metering would go towards the upkeep of the infrastructure.

- The Marlborough Express

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