Appeal of court decision launched regarding ECan’s pollution consent to MHV irrigation scheme

The Environmental Law Initiative is appealing the recent High Court judgment upholding Environment Canterbury’s decision to allow the MHV irrigation scheme to pollute water for 10 years, arguing the Court made several significant legal errors. 

“We believe the Court erred in its judgment regarding legal mistakes made by Environment Canterbury in granting the consent. 

“The pollution consented in this case will end up in rivers, drinking water, and coastal ecosystems. It is important the potential effects of this are properly addressed,” says ELI’s Senior Researcher Anna Sintenie. 

The MHV scheme covers an area of 138,000 ha between the Hakatere and Rangitata rivers. The consent allows scheme farms across the area to pollute water with wasted nitrogen from their farming activities. 

The High Court judgment released in early September found that Environment Canterbury made a material error of law in granting the consent, breaching section 107 of the Resource Management Act as it was at the time. However, because the Government had recently weakened the bottom-line protections in section 107 in favour of polluters, the Court declined to overturn the consent. 

ELI says the Court was wrong to reach that conclusion.  

“This is a huge amount of nitrate entering water. Even with the law change rushed through by the Government, our view is that the effects from the nitrate discharge associated with the MHV Water Ltd scheme are not inevitably lawful.” 

In September, Environment Canterbury declared a nitrate emergency, not long after the results of the 2025 Annual Groundwater Quality Survey found 62% of long-term monitoring sites are showing increasing nitrate trends. While five years prior, in 2020, ECan estimated that the same percentage (62 %) of private wells in the MHV area might have concentrations greater than maximum allowable value.  

“It’s a very troubling situation, and Environment Canterbury has not been getting it right in decisions on large scale discharges, as our court cases have shown,” says Sintenie. 

ELI considers that the Court was wrong to uphold the Council’s decision not to notify the public of the consent application. ECan’s own estimates showed that hundreds of private drinking water supplies in the MHV command area were at risk of exceeding the allowable value of nitrate. 

ELI also considers that the Court was wrong when it found that the Council’s failure to consider relevant coastal plans and policies was not a material error of law sufficient to invalidate the decision. 

Finally, ELI says the Court erred in finding that section 46 of the Legislation Act 2019 does not empower a consent authority to revoke an unlawfully granted resource consent. ELI says that interpretation means that when systemic errors in consent decisions are found, councils are not empowered to fix them.  

“When legal errors are made, decision makers should be able to fix them,” says Sintenie.