Council staff fear that Cloud Ocean Water, which last month began shipping water from its factory in Belfast, could threaten Christchurch's drinking water with its operation.

A bottling company's bid to take millions of litres of water from a key aquifer could threaten Christchurch's drinking supplies, warns a senior city council manager.

China-owned firm Cloud Ocean Water has this week applied to Environment Canterbury (ECan) for permission to extract water from a 186m-deep bore at its Belfast plant so it can sell it abroad.

But documents published online by a leading councillor reveal serious worries that approving the request could compromise the aquifer and leave parts of the city short of drinking water.

They also show major frustrations by council staff at ECan's handling of their concerns and its apparent failure to consult the council, issues which threaten to drive a rift between the two organisations.

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Councillors were given seven days to oppose a resource consent for the deep bore, which Cloud Ocean hopes to use alongside a shallow one to bottle around 1.5 billion litres of water a year.

The documents were posted by former mayor Vicki Buck, who chairs the council's innovation and sustainability committee.

DAVID WALKER/STUFF The firm is developing a bottling plant on the site of the old Kaputone wool scour.

In one, a submission to ECan last month over Cloud Ocean's initial application to use the deep bore, council staff said they had repeatedly raised concerns and said assessments indicated it could interfere with public water supplies.

"[The deep bore] is located within council's North West water supply zone where we are planning for a 50 per cent increase in demand over the next 30 years, 20 per cent of which is expected to be realised within the next 10 years.

"There are several future residential and industrial growth areas in close proximity to this proposal … that may therefore also trigger increased future industrial demand."

In a pointed rebuke to ECan, they said they were "deeply concerned" at the lack of "robust consultation" over Cloud Ocean's proposals, given their previous concerns.

"We strongly urge that this consent application and any future water take consent applications from this applicant are not granted before substantive consultation with the council has been undertaken about the impacts of the applicant's proposed activities on the public water supply."

The documents reveal a 17-month battle by the city council to have its views heard.

Staff first raised concerns about drilling the deep bore in July last year.

In December they asked ECan to delay approving use of the 33m bore until they had examined results of well interference testing, but permission was granted just before Christmas.

In a letter to ECan's consent planning manager this July, council head of three waters John Mackie said environmental modelling clearly showed Cloud Ocean's use of the bores would have a "significant adverse effect on the city council as a drinking water supplier".

There was "no doubt" that extracting from the deeper bore "anything close" to the permitted amount would harm the council's drinking water supply, he said.

SUPPLIED Councillor Vicki Buck published documents online outlining the extent of the city council's opposition to the water bottling company's activities.

Mackie also urged ECan to inform the council of applications to use the deep aquifer and to consider publicly notifying the consent – allowing residents to have their say – because of the "need to protect the availability of water for drinking supplier purposes".

Buck told Stuff the council was worried Cloud Ocean's operations could leave insufficient drinking water for residents and lead to contamination of its own bores, and expressed disappointment that the public had not been consulted.

"I would have thought that anything that affected the quality of the drinking water of an entire city, that would have been an issue of more than minor importance and would have allowed for a lot of public engagement."

DAVID WALKER/STUFF The firm has applied to Environment Canterbury to take water from a deep bore. Christchurch City Council is opposing it, partially over fears of potential contamination.

She added that the council, as the drinking water authority, had been very clear with ECan about wanting consultation over Cloud Ocean but had seen little engagement.

ECan chief operating officer Nadeine Dommisse said the organisation was "very aware" of the council's concerns and that it would ensure a "robust and stringent" process for Cloud Ocean's applications.

If environmental effects were assessed as more than minor – which Mackie considered possible – the application would be publicly notified, Dommisse added.

Cloud Ocean says independent testing carried out on behalf of ECan found the deep bore has "no effect on the Christchurch water supply". Its application and aquifer test results can be found here.

SUPPLIED The packaging for shipments that have already been sent contains errors, including suggesting the water comes from "Caterbury".

But Mackie appeared to cast doubt on this in his July letter, suggesting the time of year it was done had mitigated adverse effects and produced "conservative" results.

The city council will submit its concerns to ECan on Thursday after discussion by councillors.