Meridian Energy Limited v Canterbury Regional Council [2026] NZEnvC 140

Environmental / Resource Management

Case note

Meridian Energy Limited v Canterbury Regional Council [2026] NZEnvC 140

(Environment Court, Wellington, [2026] NZEnvC 140, Judge L J Semple, Commissioners I Buchanan and R Bartlett)

The Environment Court’s decision in Meridian Energy Ltd v Canterbury Regional Council provides guidance on the application of the “existing environment” concept to consent renewal applications. In the context of replacement consents for the Waitaki Power Scheme (WPS), the Court adopted a nuanced approach, holding that although the current operation of the scheme generally formed part of the existing environment, the diversion effects on the Pūkaki and Lower Ōhau Rivers had to be assessed against their natural, pre-diversion state to give effect to plan provisions requiring consideration of environmental flows at reconsenting.

Under Rule 15A of the Waitaki Catchment Water Allocation Regional Plan (WAP), the replacement water permits were controlled activities.  The associated discharge permits were also controlled activities under Rule 5.125A of the Canterbury Land and Water Plan.  Accordingly, the controlled activity provisions of the Resource Management Act 1991 (RMA) applied. Under s 104A of the RMA, the Court was required to grant consent unless it lacked sufficient information to determine whether the activities were controlled activities.  Its ability to impose conditions was also limited to matters over which control had been reserved. 

The central issue in this case was whether the diversion of the full flow of water away from the Pūkaki River and Lower Ōhau River (the diverted rivers) under the current consents should continue without provision for a permanent environmental flow regime.

This issue was a particular focus because the matters of control in Rule 15A of the WAP included:

In respect of flows into the Pūkaki River, the Lower Ōhau River or the Tekapo River (above the confluence with the Forks Stream), adverse effects, including effects on Ngāi Tahu culture, traditions, customary uses and relationships with land and water, unless the environmental flow and level regimes for these rivers have been reviewed after the public notification date of this rule and the outcome of the review has become operative in accordance with clause 20 of Schedule 1 to the Resource Management Act.

The Court’s analysis of this issue turned on how the “existing environment” was defined.  That definition determined whether the ongoing dewatering effects of the WPS could be assessed.

Competing approaches to the definition of “existing environment”

Meridian’s position

Meridian argued that the “existing environment” should be defined as the current environmental state, including all changes made by the operation of the WPS under its existing consents.  Meridian said that it would be “both fanciful and unrealistic to exclude the WPS and its operation from the existing environment”.  Meridian said:

the environment has been extensively modified by the WPS which has resulted in physical and hydrological modifications which are permanent and irreversible and the “physical, social and economic environment is shaped by the WPS and cannot be ‘undone’”.

Forest & Bird’s position

Forest & Bird disagreed and submitted “that there is a more nuanced and appropriate approach to the consideration of effects available”.  Forest & Bird accepted:

… in terms of Ngāti Rangi, that both a pre-scheme unmodified state (Eden) and an abandoned and unmanaged WPS (Armageddon) are fanciful and unrealistic.  However, it says the appropriate response to that is not to simply look to the current environment but rather to “consider different ways in which water could flow through the scheme”.  It says that to do otherwise risks treating water permits as carrying existing use rights which the Court in Ngāti Rangi determined would “cut across the sustainable management objectives of the RMA.

It submitted that:

… Meridian’s approach to describing the existing environment would rule out meaningful consideration of environmental flows when the WAP expressly anticipates such consideration.  The Court must be able to apply the matters of control in Rule 15A, especially the potential for environmental flows to address adverse effects.  A description of the existing environment that would prevent the meaningful application of these provisions cannot be supported.

The Council’s position

The Council accepted a “real world” approach but cautioned that the existing environment should not be defined so strictly as to exclude assessment of the WPS’s ongoing effects on re-consenting, given the finite nature of water and discharge permits.

The Environment Court’s assessment

Applying Alexandra District Flood Action Society Inc v Otago Regional Council [2005] NZEnvC 279 (20 July 2005), the Court confirmed that there is no invariable principle for defining the existing environment and that “each case turns on its facts” [117]. 

Following the High Court’s decision in Ngāti Rangi Trust v Manawatu-Whanganui Regional Council [2016] NZHC 2948, the Court adopted the starting proposition that “water and discharge permits under renewal should generally not be included within the existing environment”.  In doing so, the Court noted at [118] that:

To do otherwise is to risk treating water permits as a permanent consent, which as the High Court noted has the potential to “cut across the sustainable management objectives of the Act”.

Consistent with the High Court’s decision Ngāti Rangi, the Environment Court considered whether it would be “fanciful” or “unrealistic” to assess the existing environment as if the activity being renewed did not exist. The Court found at [119] that:

… the combination of the permitted activity status for structures, coupled with the controlled activity status for water related activities together with the very limited matters of control reserved to a decision maker (and particularly the prohibition on altering environmental flow and level regimes, minimum lake levels, annual allocations to activities or the provision of flows into the Lower Waitaki River) renders it unrealistic, and indeed unnecessary, to consider anything other than the current environment in most instances, in part because even if an adverse effect was identified by such an assessment, no useful condition could be imposed.

However, that was not the case across the board, as the Court found that Rule 15A of the WAP specifically anticipates a review of flows in the Pūkaki and the Lower Ōhau Rivers at the time of renewal (or on a review). 

At paragraph [120], the Court noted:

Rule 15A is clear about that and as we have already established, for such a review to have any utility, the assessment must be against those rivers as they were prior to diversion, not as they are now.  To do otherwise would render the matter of control nugatory and we cannot accept that to be consistent with the purpose of the WAP or its originating legislation.

Therefore, while the Court held that the current, modified environment constituted the “existing environment” for most aspects of the WPS, a different approach was required for the assessment of river flows into the Pūkaki and the Lower Ōhau Rivers.  This nuanced approach was required to give meaningful effect to Rule 15A of the WAP.  The Court concluded that, for the purpose of assessing whether environmental flow requirements should be imposed under that rule, the effects on those rivers need to be assessed against their pre-diversion, natural state, rather than as they are now. 

By defining the existing environment for these two rivers as their pre-diversion state, the Court was able to recognise the ongoing loss of river extent and values caused by the diversions.  This was pivotal in enabling a meaningful review of whether an environmental flow regime should be imposed, as required by the planning framework.  Ultimately, however, the Court found that imposing such a regime was not appropriate at this time for practical, cultural, and economic reasons. It granted the replacement consents subject to a comprehensive suite of conditions.  The decision nevertheless ensures that the effects of the original diversions are properly assessed and that the planning framework’s intent is fulfilled.

Implications

The Meridian decision demonstrates that the identification of the existing environment on 
consent renewal is not simply a choice between a pre-development state and current 
conditions. Rather, the appropriate approach may depend on the purpose and wording of the relevant planning framework. Where planning instruments expressly contemplate review of environmental flow and level regimes for certain rivers, the Court may be required to assess the effects of water takes against a pre-diversion state of the relevant rivers to give meaningful effect to those provisions. 

In that respect, Meridian may be contrasted with the approach adopted by the expert panel for the Tekapo Power Scheme applications under the Fast-track Approvals Act 2024. The expert panel, in its decision on the Tekapo Power Scheme, determined that the existing environment includes both the physical infrastructure and the ongoing, consented operations of the scheme (water takes, diversions, damming, and discharges). As a result, the Tekapo Power Scheme expert panel assessed only the ongoing residual effects of the scheme, treating the diversion of the Tekapo River as part of the existing environment rather than as an ongoing effect. The Tekapo decision is currently under appeal. 

The Environment Court’s decision in Meridian is highly relevant to future consent renewal 
cases because it provides guidance on the circumstances in which the Ngāti Rangi "fanciful 
or unrealistic" exception applies. The exception is context dependent. In Meridian, it justified using the current environment for most of the WPS, but not for the Pūkaki and the Lower Ōhau Rivers, where the relevant plan provisions specifically anticipate review of environmental flow and level regimes for those rivers at reconsenting.