Summer water restrictions in Kaitaia should become less frequent in future, as the Far North District Council works to make the town's supply more resilient.
The council's general manager – infrastructure and asset management Andy Finch, said yesterday the sprinkler ban imposed last week had once again highlighted the supply's vulnerability to drought.
Mr Finch gave an assurance that "considerable" work was being done to achieve that. The plan to take water from the Aupouri aquifer had been deferred until a robust business case had been developed and all other options had been explored, and good progress had been made.
The council had recently received a hydrogeological study from Lincoln Agritech comparing different extraction options from the Aupouri aquifer, using a mathematical model to estimate the yield and quality of potential bores within 10km of Kaitaia, and with road access and electricity.
A number of potential bore sites, including the Sweetwater bore, for which the council had a consent, had been identified.
"This answers many questions about the suitability of the aquifer as an alternative water source. In the meantime, we have been working to make other parts of Kaitaia's water supply more resilient," Mr Finch said.
The traditional approach of reducing leakage had been under way for more than two years. A number of leaks had been found and mains breakages prevented, but substantial quantities of water were still unaccounted for, likely due to a combination of numerous small leaks, often the result of the historic use of materials with a high failure rate, and inaccurate water meters.
The council had now engaged an expert to provide a systematic strategy to locate hard-to-find leaks and identify meters requiring replacement.
It also planned to undertake a study of flows in the Awanui River during drought conditions to assess whether the current consent limit could be safely lowered. That could only be done in drought conditions, which had not existed over the past two summers. It was possible that conditions would be suitable this summer.
Meanwhile staff were preparing a report on the options for councillors to consider within two months.
Mr Finch added that the Northland Regional Council limited the take from the Awanui River, Kaitaia's primary source of water, to safeguard its ecosystem and possible impact on users downstream. The river flow should not fall below 460 litres per second at the point where water was taken.
The Kauri provided a back-up water source, but was unusable in summer because of algal blooms. The council resolved last year to stop using the dam, but had not specified a timeline for that.
The NRC consent to take water from the Aupouri aquifer had not been taken up, but had been rolled over, and remained valid.
Juken NZ, whose triboard mill used about 25 per cent of the water produced by the Kaitaia treatment plant, worked with the council to reduce consumption during dry weather.