ELI challenges ECan’s consent to MHV for nitrate pollution in High Court

ELI is challenging the lawfulness of a nitrogen discharge consent issued by Environment Canterbury in the High Court this week. The consent to the MHV Water Ltd irrigation covers farming activities on more than 58,000 ha of land. 

“The Council has allowed industrial-scale pollution to drinking water and freshwater habitat in the area between Hakatere/Ashburton River and the Rangitata River. 

“It did this, we allege, without properly taking into account the effects of nitrogen discharges on drinking water supplies,” says ELI’s Senior Legal Researcher, Lottie Boardman. 

Environment Canterbury granted the consent to the MHV Water Ltd irrigation scheme in 2021, without notifying local community drinking water operators or owners of private drinking water wells in the area. 

High levels of nitrogen in waterways can cause excessive algae growth and oxygen depletion. This process, known as eutrophication, harms aquatic ecosystems by creating "dead zones" where fish, insects and other wildlife struggle to survive.  

Additionally, elevated nitrate levels in drinking water sources can pose serious health risks, particularly to infants. 

It is ELI’s second High Court challenge against Environment Canterbury for nitrate pollution in as many weeks. 

The first hearing, heard in the Christchurch High Court last week, challenged a rule in the Canterbury Land and Water Regional Plan, which allows nitrogen pollution of freshwater by farms. ELI told the Court that this rule was unlawfully put in place by Environment Canterbury without meeting the requirements of section 70 of the Resource Management Act. 

According to the figures from MHV’s 2024 consent compliance report, in that year MHV farms were collectively consented to discharge up to an estimated 3,694,000 kilograms of excess nitrogen into groundwater.2  

ELI’s cases builds on an earlier success against Environment Canterbury’s decision to grant a consent to Ashburton Lyndhurst Irrigation Limited (ALIL), which neighbours the MHV irrigation area. In March 2024, the High Court found that Environment Canterbury’s decision to grant the discharge consent was based on a material error of law, and the consent issued to ALIL was set aside. 

In addition to challenging Environment Canterbury’s decision to grant the consent, ELI is challenging the council’s failure to take steps to revoke MHV’s consent when it became clear that it had been granted according to the same approach found to be unlawful in the ALIL case. 

“We want Environment Canterbury to be guaranteeing communities have access to clean drinking water and protecting freshwater ecosystems,” says Ms Boardman.