Expert Witnesses in the Environment Court (and consent Hearings) must be held to account

Opinion by Dr Peter Trolove

, Expert Witnesses in the Environment Court (and consent Hearings) must be held to account
Rakaia river mouth 2011


The Ministry for the Environment is presently drafting legislation to replace the RMA (1991) which has been judged not fit for purpose – The Natural and Built Environments Bill.

The Environmental Law Initiative Environmental Law Initiative ( has made a considered (legal) submission in response to the Natural and Built Environments Bill;

Natural and Built Environments Bill: Our Submission — Environmental Law Initiative (

While it is true that the fate of New Zealand’s freshwater is decided by law, the law has been badly let down by suspect scientific evidence provided by sworn expert witnesses in particular at consent hearings overseen by Government appointed Ecan commissioners, appointed under the Ecan Act 2010.

Without mandating some form of accountability backed by strong sanctions, “expert” witnesses will continue to sell their services to the highest bidder to the detriment of our freshwater.

The 2012 Lake Coleridge Project Hearing – A Case Study

The Environment Canterbury Temporary Commissioners and Improved Water Management Act, (2010), enabled Ecan, (the Canterbury Regional council), to conduct a Hearing to consider Trustpower’s application to amend the National Water Conservation Order Rakaia River (1988) to abstract a further 57 cubic meters from the Rakaia River flows to provide irrigation water for the Barrhill Chertsey Irrigation (BCI) and the Central Plains Water (CPW) enhancement irrigation schemes.

Nearly 10 years on it is clear to anyone with an interest in the fate of one of Canterbury’s largest iconic braided rivers, that the effects of the consented amendments from the 2012 Lake Coleridge Project (LCP) Hearing have been far greater than the “minor or less than minor” effects claimed by the applicant’s hired experts.

The primary purpose of the Rakaia NWCO was to protect the outstanding landscapes, fisheries, recreational fisheries and jet boating that once existed in this popular braided river less than one hour’s drive from the South Island’s largest city.

Since the BCI irrigation scheme and Stage II of CPW have been completed the Rakaia River has seen;

  • A decline in salmon returns to around 1/10 of expected numbers
  • The destruction of a once prolific sea trout fishery
  • The near extinction of Stokell’s smelt, (an Internationally Red Listed Endangered species due to its limited geographical range), once the largest fishery by mass that supported much of the ecology of the river mouth or hapua zone
  • A marked decline in the breeding success of endangered Black Billed Gulls and White Fronted Terns due to the loss of the once massive shoals of Stokell’s smelt.
  • At least a 50% drop in the populations of the 5 species of birds that are specialized inhabitants of braided river beds
  • Unsympathetic river management by Ecan’s river engineers as they attempt to mitigate increased flood risk due to the river being no longer able to transport gravels in equilibrium with erosion.
  • Loss of wetlands, and productive secondary and tertiary braids within the flood plain
  • Loss of thousands of hectares of riparian margins to agricultural encroachment
  • The defoliation of the braid beds due to Ecan’s annual aerial spraying with glyphosate and toxic surfactants that has altered the braid structure destroying habitat, soil ecology, and limiting jet boating access during times of low flow. Put simply the lower braids have become little more than a featureless “shingle slide”.
  • A marked increase in mud/fine sediment in the lower braids and around the margins of the lagoon and connected creeks.

While the Hearing Commissioners determined that the issue of groundwater pollution from the out of river use of the abstracted Rakaia River water would be the subject of future consent hearings, the CPW irrigation scheme has caused measurable increases in nitrate levels in the groundwater beneath vulnerable irrigated Central Canterbury soils leading to Eco toxic nitrate levels in the Selwyn District’s aquifer fed rivers and streams. Ecan’s subsequent decision making on this matter was critically recorded in a 2015 submission by the Environment Institute of Australia and New Zealand Inc.

19.11.2015 – Submission Environment Canterbury Bill Transitional Governance Arrangements Bill1.pdf

“In the Central Plains Irrigation hearing for example, the commissioners did seek independent advice under section 41. Advice was sought but this advice was largely ignored in reaching their decision. That advice indicated that: • several nitrogen thresholds were likely to be exceeded: nitrates in drinking water was already in excess of the nitrate health standard in 5% of groundwater monitoring wells and the effect of Central Plains development was to increase this percentage; • the groundwater-fed streams exceeded the periphyton and macrophyte guidelines for nutrients and the Central Plains Scheme would make this worse; • the nitrate toxicity in groundwater-fed streams was above the ANZECC Guidelines criteria and would be increased by Central Plains; and, • the increased groundwater flow and increased nitrate levels would increase the Trophic Level Index for Te Waihora Lake Ellesmere from 7 to 7.2 when the TLI goal for the lake is 6.0. • even without Central Plains, nitrate levels in the catchment would get worse as effects on groundwater from current land use intensification eventually reached the groundwater-fed streams and Te Waihora Lake Ellesmere. In their decision, the RMA Hearing Commissioners stated they had considered the advice provided in the Section 41 report but they did not explain why the matters raised in that report failed to influence their decision which was to approve the application.”

These outcomes are not “minor or less than minor”

In terms of the amendments to the original Rakaia River NWCO the outcomes have been major, and in the case of Stokell’s smelt critical.

The Experts

Expert witnesses hired by Trustpower who stated under oath in their respective Statements of Evidence that they were expert and that they would abide by the Code of Conduct for Expert Witnesses in the Environment Court 2011 include;

Ian Jowett

Rob Greenaway

Ross Dungey

Richard Alibone

Martin Unwin*

*Of the witnesses named above Martin Unwin professionally stated what was known and what was poorly understood, and what was not known about the Rakaia River salmon fishery. However this did not prevent him giving his expert opinion that the effects of the LCP would be “minor or less than minor”.

Due to a lack of understanding of the complexity and interactions between the geomorphology, flow variability, and species that make up the catchment-wide ecology of the Rakaia River, the three Hearing commissioners were obliged to depend on expert opinion in lieu of verifiable scientific evidence. Expert opinion that is referred to throughout the 107 pages the commissioners wrote in defence of their decision.

No doubt the Chair of the Hearing commissioners, Hon. Peter Salmon, was prompted by his legal experience and concern for his own reputation when he required sworn affirmations from the experts to adhere to the Code when he set the Terms and Conditions for the LCP Hearing.

The Code required the “experts” to state where they could reliably defend their expertise and where they were not expert. If other submitters were to show their evidence was unreliable, inadequate, the Hearing must consider them not to be experts.

The LCP Hearing was conducted under the Ecan Act 2010, S. 52 of which excluded the jurisdiction of the Environment court, while S. 53 allowed a right of appeal to the High Court on points of law.

It is a tragedy that the Key Government drafted legislation that targeted irrigation development to the exclusion of balanced technical & scientific debate.

An un-validated and un-verified model, RHYHABSIM, was applied to the middle reaches of the Rakaia River where modelled “habitat”, (or space in the river), was not limiting. This made the results meaningless, yet the modelled “answers” formed the framework on which the unfounded “expert” opinion was based.

If these witnesses had acted in accordance with the Code they had sworn to abide by, the Hearing commissioners may have reached a different decision after giving regard to the Vision and Principles of the Canterbury Water Management Strategy…..”a cautious approach is taken when information is uncertain, unreliable or inadequate”

Should these experts whose opinion sealed the fate of the Rakaia River be given immunity from the consequences of their (incorrect) expert opinion?

None of these experts visited the hapua zone where 95% of the fishery exists (existed) [S.F. Davies et al. 1983] before giving their (expert) opinion.

Why should these hired experts be allowed to offer” expert” opinion at future environment hearings?

The New Zealand Federation of Freshwater Anglers believes in a Code of Conduct for expert Witnesses in the Environment Court and at equivalent environment hearings.

The NZFFA however believes that witnesses who have sworn to abide by the Code should be held to account, (and that Regional Councils should be held to account to the Codes that apply to their decisions).

Dr Peter Trolove

President NZFFA

Submitter against the LCP

, Expert Witnesses in the Environment Court (and consent Hearings) must be held to account

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7 Responses to Expert Witnesses in the Environment Court (and consent Hearings) must be held to account

  1. Charles Henry says:

    In today’s world, we now encounter “Post-Normal Science”. Although perhaps started with noble ideals, like anything it is easily corrupted (see,Ravetz.)
    The basis of any true “Science” or the true “Scientific Method” involves 5 basic steps:
    1 Make an observation.
    2 Ask a question.
    3 Form a hypothesis, or testable explanation.
    4 Make a prediction based on the hypothesis.
    5 Test the prediction.

    Then Iterate: use the results to make new hypotheses or predictions.
    If you cannot exercise step 2, ask a question, it cannot be science.
    If you cannot ask a question, it is not science it is dogma.
    Even the word “Expert” raises hackles in me these days. We see all the time self-proclaimed “Experts” be it Climate Change or Covid-19. The fact that they cannot be questioned proves their lie.
    As part of post-normal science, “peer-review” becomes “pal-review” – almost a return to the back of the playground “you show me yours, I’ll show you mine” sort of stuff.
    Scientists? Experts?
    Bah Humbug!

    NZFFA - New Zealand Federation of Freshwater Anglers

    • Terence Rumble says:

      Charles Henry is so correct. Science has been prostituted by “commissioned, paid science”.

  2. Grant Henderson says:

    Any development a government or developer has wanted to push through has been backed by an “expert” opinion saying the effects of the development would be minimal. These people know what side of the bread has the butter and jam.

    Think of the Wheao river dam, which collapsed a few days after it was commissioned, or the Opuha dam.

    A major problem in the law is the lack of a precautionary test to safeguard the environment, ie people opposing a dam or irrigation scheme must prove there will be damage. The assumption seems to be that all development is beneficial and should go ahead unless there is good reason not to (think of all those jobs, after all).

    Compare that to the tax system. If you want to contest a tax assessment, you have to prove the IRD got it wrong. As natural resources are finite, we should be using that approach to preserve natural capital.

  3. Predator Pete says:

    Selling reputations to consent hearing applicants is what it is.
    Despite Codes or laws.

  4. Grant Henderson says:

    “Independent commissioners working on behalf of the Northland Regional Council today granted a group of 22 landowners consent to take 4.5 million cubic metres from the Aupōuri aquifer.

    The water will be used mainly for avocado orchards.

    Of the 113 submissions received on the application, 92 were opposed.
    Among them was Kevin Matthews, who chairs local conservation group Bushland Trust, and said there were questions about the information the consents were granted on.”
    [Radio NZ, 1 Sept 2021]

    In 10 years’ time, Northland will look like California does now, is my guess.

  5. Grant Henderson says:

    Stuff item, 20 Sept 2021: “Regional council over-allocates water takes on Mataura river”.

    No doubt there is an expert’s report somewhere saying the effects of the water takes would be minimal. They’ll keep on writing those reports until the river dries up.

  6. Grant Henderson says:

    Stuff report, 21 Sept 2021:

    “The Department of Conservation is appealing to the Environment Court against controversial Far North Aupōuri Peninsula water consents for avocado growing.”

    Seems DoC is doing its job for once.

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