Forest & Bird has lifted the lid on what it claims to be a massive water theft in Canterbury.
The conservation group has released data obtained under the Official Information Act showing those with consents to take water have taken hundreds of millions of litres more than they were entitled to.
The information reveals water was illegally taken from creeks that eventually ran dry, including during low-flow restrictions when rivers were at their most parched.
Environment Canterbury (ECan) did not prosecute any of 376 cases of serious breaches, despite many offenders being caught "red-handed", Forest & Bird says.
One case includes an irrigator who was found to have illegally taken 31 million litres of water from the Manuka Creek over 42 days. Forty of those days were during low-flow restrictions. The offender received an abatement notice.
"Elsewhere in New Zealand abatement notices are taken very seriously. However, in Canterbury, irrigators seem to be able to ignore them with impunity," Forest & Bird lawyer Peter Anderson says.
"Commissioner [David] Caygill's recent indication that ECan should treat consent breaches more seriously is welcome, but until ECan starts taking strong enforcement action we will continue to see irrigators ripping off their neighbours, their community, and the wildlife that depends on Canterbury's rivers and waterways."
Forest & Bird: 'Do your job'
Forest & Bird advocacy manager Kevin Hackwell says ECan is not doing its job properly.
"It's a huge problem in the sense that we're seeing lots of rivers running dry during the summer," he says.
"We're seeing the wildlife suffering."
Forest & Bird advocacy manager Kevin Hackwell
Mr Hackwell says ECan itself has admitted there's significant non-compliance of water consents, with one farmer avoiding prosecution four years in a row.
"The irrigators who are not in breach, who are doing things properly, they're being ripped off by their neighbours who are actually doing things wrong," he says.
"Nobody benefits at all. ECan, which is meant to be looking after the public water resource, has been very keen on seeing irrigation occur and promoted."
This has created conflict, Mr Hackwell believes, between the politics of wanting more irrigation and the requirements of the law to manage a public resource properly. He says the there's something "seriously wrong" with the culture at ECan in managing the resource.
"Do your job properly," he says.
Environment Canterbury response
ECan says several investigations have taken place over the past two seasons for consent breaches, but there has not been enough evidence to warrant prosecution.
"The evidence required for pursuing a prosecution is very high," principal resource management advisor Richard Purdon says.
"It is also important to note there are four possible aspects to a significant non-compliance: taking water while a river is on restriction, taking over the allocated amount, faulty water-measuring devices or not submitting data to Environment Canterbury."
Non-compliance is taken "very seriously", Mr Purdon says.
There are 5900 water takes in Canterbury, three times the number of any other region in New Zealand.
Mr Purdon says ECan has worked with water consent holders to achieve compliance since water metering rules took effect in 2012.
"Our experience is that once consent holders know what is expected of them, they want to comply and take action."
Mr Purdon says ECan is implementing "the most comprehensive package" of measures to improve water efficiency and reduce nutrient leaching to deliver a "significant improvement" in land use management.
More than 90 percent of water takes which require meters in Canterbury are now being measured and reported.
"All those who have yet to install meters -- around 9 percent, or 500 consent holders -- have been contacted and warned they face enforcement action if they don't take urgent action," Mr Purdon says.
He says many people took action within 10 days, and those who didn't were issued with abatement notices.
Water data for the last irrigation season will be submitted to ECan this month, and Mr Purdon says enforcement action will be taken against those who are breaching their consents.
Green Party weighs in
The Green Party has spoken out, saying ECan is failing in its role to protect Canterbury's rivers and the environment.
New Ministry for the Environment data, analysed by the Green Party, shows ECan was expected to monitor over 20,000 consents in 2014/15, but only monitored 3200.
Of those monitored, more than half were not complying with their consent conditions.
"Canterbury is fast becoming a Wild West, with too many environmentally risky activities going unchecked by the council," says Green Party environment spokesperson Eugenie Sage.
"ECan's relaxed approach to environmental monitoring and enforcement has seen numerous instances of stock being allowed into waterways, and is contributing to the long-term degradation of Canterbury rivers."
ECan chief executive Bill Bayfield says it's a "wake-up" call to water users that breaches will be taken seriously.
He says the amount taken illegally compared to water taken legally is "relatively small", but he understands the concern.