How the Rakaia turned into a pipe for irrigators

From by David Williams

In the 2021/22 season, the South Island’s largest irrigation company, Central Plains Water, supplied its farmers with 105 million cubic metres of water from the Rakaia River, 42 percent of which came from Lake Coleridge. Photo: Francis Vallance/Flickr/Creative Commons
In the 2021/22 season, the South Island’s largest irrigation company, Central Plains Water, supplied its farmers with 105 million cubic metres of water from the Rakaia River, 42 percent of which came from Lake Coleridge. Photo: Francis Vallance/Flickr/Creative Commons


How the Rakaia turned into a pipe for irrigators

Problems with protecting the Rakaia River were predicted years ago, documents filed in the Environment Court show. David Williams reports

Analysis: When Canterbury’s regional councillors were sacked 13 years ago, the John Key-led Government told the public the region had “urgent problems with water management”.

“Canterbury is strategically important with it holding more than half of the country’s irrigation water and hydro storage,” then Environment Minister, Nick Smith told The Press newspaper.

He underlined his point by saying freshwater was to New Zealand what oil was to Saudi Arabia.

(The immediate reaction from ECan’s sacked deputy chair Jo Kane was: “To me, it smacks of them grabbing the gold.”)

Regional council admits it’s been flying blind on Rakaia
Court puts river protection case on fast-track

To unleash the resource, commissioners appointed to the regional council, ECan, were to be given new powers.

“Government leadership is needed to address Canterbury’s lack of a proper allocation plan, increasing problems with water quality and the failure to progress opportunities for water storage.”

As luck would have it, a water storage plan was already on the table.

Only months earlier, Cabinet ministers were briefed on a plan to store irrigation water at Lake Coleridge/Whakamatau, where NZX-listed power company Trustpower (now called Manawa Energy) had a hydro-electricity power station.

The plan fitted neatly with a massive farm irrigation project known as Central Plains Water, which was on the lookout for a new reservoir after an independent hearing panel indicated it would reject a plan to build a 55-metre-high dam in the Waianiwaniwa Valley, about 60km west of Christchurch.

However, using Coleridge as a stand-in irrigation lake had one big obstacle – a water conservation order which banned water takes from above the Rakaia Gorge.

Bede O’Malley, at that time the Ashburton Mayor, led the Canterbury Water Management Strategy, an attempt by the region’s mayors to solve contentious water issues. He told The Press in late 2009 Coleridge was the frontrunner to be a pilot scheme under the strategy, and the ban was “not insurmountable”.

The lake had the perfect setup for power generation and irrigation, Central Plains Water Trust chairman Pat Morrison gushed. The trust had previously ruled out Coleridge because of the water conservation order. “That’s obviously a Government decision,” Morrison said.

Sixteen months after regional councillors were sacked, Trustpower applied – under temporary ECan legislation – to alter the conservation order.

Ultimately, ECan adopted the independent hearing panel’s recommendation to vary the water conservation order, something which Canterbury Earthquake Recovery Minister Gerry Brownlee formally accepted in 2013.

Not only would farmers get irrigation water when the river ran low, ECan concluded the amendment would “continue to preserve and protect the outstanding natural characteristics, habitats and features of the Rakaia River”.

Brownlee said the project was “a good example of both environmental considerations and the needs of the farming community being taken into account”.,dpr_auto,f_auto,fl_lossy,q_auto,w_750/v1/cog-aap/n/303/2023/Feb/24/K4NxsEEaOd88A93NjXcN.jpg Construction started on a hydro scheme at Lake Coleridge in 1911. Photo: Tomas Sobek/Flickr/Creative Commons

The application’s success, and the construction of Central Plains Water, which is now the South Island’s largest irrigation company, bubbled along for years with some fanfare, and protest. More reliable water for irrigation started to flow, like Saudi oil, in 2015.

News of potential problems only emerged in late 2021, not from official sources but a Newsroom story about a leaked, unpublished report by a senior regional council scientist.

The report suggested the water conservation order was being breached and water-take consent limits were occasionally being exceeded.

The latest twist in this story happened last month when Environment Canterbury filed an application for declarations in the Environment Court – centred on whether it had legal obligations to monitor and report on the conservation order.

Newsroom’s reporting has already brought to light important background, including a legal letter sent by ECan in 2015 advising Trustpower to seek a court declaration to ensure its new water accounting system at Lake Coleridge didn’t breach the order.

The company implemented the system regardless.

In a fresh irony, ECan has now asked the Environment Court – through the same law firm that wrote the 2015 letter – to endorse fundamental aspects of Manawa Energy’s system at Coleridge.

The regional council’s evidence filed to the court, released to Newsroom, includes Trustpower’s 2011 application to vary the conservation order, and the hearing panel’s recommendation the following year.

Examination of these documents helps to fill some gaps, and answer key questions about how the Rakaia was turned into an irrigation pipe.

A classic win-win

In its application, Trustpower assured it wasn’t dismantling the order’s protections, and mooted the move to irrigation was a win for both the environment and economy.

“The various assessments that have been commissioned in the preparation of this application have endorsed this approach and have concluded that the proposed amendments to the Rakaia order will not impact on the continued protection of the river’s outstanding characteristics and features.”

Particular importance was placed on the Canterbury Water Management Strategy, which by then had been enshrined in the ECan Act.

“The Lake Coleridge Project is considered to achieve the vision of the strategy as it will enhance social and economic wellbeing through increased electricity generation and improved agricultural production, while also ensuring that the highly valued (and internationally recognised) natural character, landscape, habitat and fishery values identified in the Rakaia water conservation order continue to be protected.”

Hydrological consultants Tonkin & Taylor said the order changes would lead to reduced flows in the Rakaia River, and more days when the daily mean flow was lower than the minimum in the order.

Flow changes in the main channel were characterised as “relatively minor”. “Even smaller changes will result in the minor connected and partially connected braids.”

Lake Coleridge’s level would change from historical norms. Under the new regime, it would be higher from June to October, as “stored water” flowed in, and lower between January and April, when it would be released for irrigation.

That meant was the lake would fill two to three months earlier and water would be released three months earlier than was usual.

An in-stream habitat model predicted lower flows would reduce habitat for fish, benthic invertebrates and birds, except adult brown trout and wrybill plovers. But, the report said, the Rakaia was “particularly inhospitable” for aquatic species because of floods, turbidity and sediment movements. As such, these small changes will have “no material effect”.

There was a strong economic argument for approving the project.

Once irrigation was in place, and land converted to different uses, consultants NZIER concluded an extra $477 million could be earned through selling agricultural produce. Trustpower would make up to $9.2 million a year more through extra electricity generation.

In summary, the proposal would have environmental effects but, according to Trustpower’s application, they were likely to be minor or negligible.

Not everyone agreed.,dpr_auto,f_auto,fl_lossy,q_auto,w_750/v1/cog-aap/n/303/2021/May/09/kpQa7sFXXD1IKEcWbfyu.jpg Between 2002 and 2019, irrigated land in Canterbury almost doubled to 467,000 hectares. Photo: David Williams

The application to alter the Rakaia water conservation order went to public hearings in the first half of 2012.

Given the river’s importance to Māori it was no surprise Ngāi Tahu voices made waves.

Kaumatua Tā Tipene O’Regan supported increasing water storage in Whakamatau but said the issue at stake “was the retention of an adequate volume of water in the Rakaia to ensure that natural processes continue, that Ngai Tahu’s traditional mahinga kai is supported and the river is restored to its former abundance”.

The potential to increase the frequency, magnitude and duration of low flows within the Rakaia River was of particular concern for Ngāi Tahu, said Niwa’s Dr Charlotte Severne. She raised the spectre of the conservation order amendment setting off a cascade of unintended consequences.

(“It is an issue which we have considered carefully,” the hearing panel said, in its report. The order’s integrity was “central to these recommendations”, it reinforced repeatedly.)

Mandy Waaka-Home, speaking on behalf of hapū of Kāti Huirapa, said current protections were adequate but she worried about them being eroded, and the knock-on effect on the river’s mauri, or life force.

As tautiaki, or guardian of the river, there’s a responsibility to maximise the mauri of the river for future generations of Ngai Tahu, and the nation as a whole.

She also expressed concern at the lack of monitoring of the original conservation order. This point was also picked up by a consultant hydrologist, who expressed “concern at the limited monitoring that has taken place since the original order was granted”.

Some witnesses seemed troubled by what might happen.

ECan principal planning advisor Leo Fietje noted many of the effects allowed within the scope of the water conservation order hadn’t materialised “because not all of the water which can be taken from the river has yet been taken”.

Meanwhile, fisheries biologist Don Jellyman, of Niwa, summarised his evidence by saying the effect on native fish should be “in the scale of minor to less than minor”. But he felt compelled to say “the proposal was a small but incremental erosion of the principle the water conservation order drew a ‘line in the sand’.”

One of the strongest comments at the hearing came after the appearance of David Caygill, a former Labour Party minister who was appointed an ECan commissioner, and had responsibility for water issues.

Caygill told the hearing that parties to the Canterbury Water Management Strategy accepted increased storage was essential, and Trustpower’s application was aligned with the strategy. More, it “creates an opportunity for an integrated storage solution for the Canterbury region”.

In Ngāi Tahu’s submission, this expression of support meant the regional council’s position was “no longer neutral”.

This was dismissed by the hearing panel, who said Caygill’s evidence was demonstrated how the proposal supported the strategy’s objectives. “There is nothing wrong with that.”

ECan’s lawyer, Philip Maw, was questioned by the panel about whether the variation would delegate the council’s functions to Trustpower. He said it would not.

The wording of the variation didn’t allocate any water to the company, Maw said, rather it enabled Trustpower to lodge applications for resource consent, and the council “retained control over the water resource in its capacity as consent authority”.

The hearing panel’s 108-page report weighed the arguments, and the “rather complex water accounting requirements”, and endorsed the application.

In doing so, it commented Trustpower “will need to carefully monitor and record all flows in and out of the system, and keep daily records of the amounts of ‘stored water’ and ‘normal water’ in the lake, and discharged”.

Darren Leftley, a senior hydrological scientist for ECan, “was confident that a rigorous monitoring and web-based management regime based on virtual gorge flows can be developed with TrustPower”.

Said the hearing panel: “We concur.”

A pathway, ideal for power generation

The Rakaia, which runs about 50km south-west of Christchurch, is New Zealand’s largest braided river, traversing about 150km from the Southern Alps across the Canterbury plains to the Pacific Ocean. Near the coast it can be up to 2km wide.

The river is extremely important to Māori, who have used it for countless generations as a pathway and food source. “For Ngāi Tahu, the variable character of the river is essential to its cultural value, and is reflective of its life force,” the 2013 Mahaanui Iwi Management Plan said.

It is also internationally important, providing rare habitat for fish, birds, insects and lizards.

An important feature of the Rakaia’s catchment is Lake Coleridge, a mountain-ringed depression scooped out over millions of years by the repeated retreat of glaciers. The 18km-long lake has a natural fall to the Rakaia River of about 150m, making it ideal for electricity generation.

Construction started on a hydro scheme there in 1911 and by 1915 the Coleridge power station supplied most of Christchurch’s electricity.

The original Rakaia water conservation order, made in 1988, set quantity and flow rates for the main stem of the river, but also required the Wilberforce catchment, including the Harper River, be retained in its natural state.

Using Coleridge water for irrigation wasn’t contemplated or allowed.

Trustpower already had consents for the hydro scheme at Coleridge, bought from Electricity Corporation of NZ in 1998, when it applied to alter the Rakaia order in July 2011.

(Trustpower rebranded as Manawa Energy last year, after it sold its retail arm to Mercury Energy.)

The company’s carrot to decision-makers was the grand plan of spending hundreds of millions of dollars, eventually, building an irrigation canal, dotted with power stations, from Coleridge.

In the early stages, however, it anticipated operating within its existing consents. That is, it needed the  order to be changed to allow stored water from Coleridge to be released along the Rakaia, to be diverted by irrigators downstream.

That liquid gold would irrigate thousands of extra hectares of land.

Between 2002 and 2019, irrigated land in Canterbury almost doubled, from 241,000 hectares to 467,000 hectares – 80 percent of which was for dairy farming. In 2019, Canterbury was home to 1.2 million dairy cattle, an increase of 973 percent from 1990.

Synthetic nitrogen fertiliser use in the province has also skyrocketed, from about 31,100 tonnes in 2002 to 80,300 tonnes in 2017.

Trustpower’s proposal involved some flows into Coleridge being classified as “stored water” for irrigation, as opposed to “normal water” for power generation.

How much could be used for irrigation depended on factors such as: how far above its minimum monthly flow the Rakaia River is flowing; and how much consented water (taking into account river flows, and monthly minimums) hadn’t already been used.

The company’s 2011 application said: “Trustpower will be able to identify what proportion of water in Lake Coleridge is ‘stored water’ and what proportion is ‘normal’ water.”

Yet a year after the Government approved the conservation order amendment, Trustpower’s lawyer complained to ECan that under the lake’s restricted operating range it was losing the opportunity to store more water.

That’s why, in 2015, it implemented a new water accounting system, called warehouse stored water, which allowed water to be “stored” below the lake’s minimum operating range, and “reclassified” in the top level when needed.

Details of this arrangement didn’t surface until 2021, when Newsroom revealed details of the leaked ECan report.

Years of complaints

It’s worth remembering, a major reason for ECan agreeing to study the Rakaia in the first place was years of complaints from river users, like fishers, jetboaters and kayakers, about low flows and water levels, despite the supposed protection afforded by the water conservation order.

Fresh evidence, published last year, came from a Niwa report commissioned by ECan, capturing the observations of veteran anglers on the Rakaia, Ashburton/Hakatere and Rangitata Rivers. It said: “To many, the very heart of these rivers has been ‘ripped out’ by over-abstraction of surface and ground water.”

The leaked report noted since the order was amended “irrigators have reported that flows have become more unreliable”.

(The report’s author, senior hydrological scientist and data analyst Wilco Terink, left ECan after his bosses insisted contentious findings from the report should be removed.)

The reality is water diverted into Coleridge – from the Wilberforce, Harper, and Acheron Rivers – robs the Rakaia even when the river’s running low, because those diverted flows would otherwise have flowed into it.

As to promises of monitoring the Rakaia after the conservation order amendment, ECan’s evidence filed in the Environment Court reveals it has been scant.

An affidavit from Richard Purdon, a principal consents planner, said: “Historically there has been very little dedicated water-take compliance activity undertaken on the Rakaia River, beyond that carried out in the ordinary course of compliance monitoring more generally.”

Because Manawa Energy hadn’t sought new consents for stored water, that limited the regional council’s monitoring. Further, Manawa’s calculations for stored water, and the flows in and out of Coleridge, “is not publicly available or accessible”, Purdon noted.

A clause in the amended conservation order requiring accurate water records at Coleridge is “not actively monitored by the council’s compliance team”.

An interesting aspect of the Environment Court proceedings is ECan’s negative stance. It’s asking the court to declare it has “no statutory duty to enforce” the conservation order provisions, and it doesn’t need to directly monitor the order, nor gather its own information or keep records.

The situaton ripples back to the 2012 hearing, when the panel asked whether the variation would result in the council’s functions being delegated to Trustpower.

“We did far more to address the environmental challenges [than] … facilitate irrigation storage.”
– David Caygill

Some say what happened at Lake Coleridge was a government-endorsed water grab.

However, former ECan commissioner Caygill tells Newsroom this is “intemperate and not a useful way of thinking about what actually happened”.

No matter what ministers had in mind for commissioners, what they got was a council that exercised its statutory powers and responsibilities, says Caygill, whose appointment at ECan lasted nine years.

“I would be very surprised if anybody could contradict this – looking at that period, we did far more to address the environmental challenges that had been facing ECan at the time we were appointed, than we actually did in the end, to facilitate irrigation storage.”

When commissioners were appointed, the council had no rules limiting the discharge of nitrate or phosphorus. “By the time we left we did have rules in place across Canterbury, that addressed both of those deficiencies.”

Caygill believes it is appropriate for ECan to go to the Environment Court if there are doubts about its responsibilities for the water conservation order.

However, Christine Rose, lead climate campaigner for environmental activist group Greenpeace, says ECan has neglected its duties when it comes to the Rakaia. Her concerns extend much more broadly.

“ECan’s failure to independently monitor and enforce this protection order undermines public confidence in the regional council, in this specific water conservation order, and in future water conservation orders, like the one in Golden Bay facing opposition from industrial dairy interests.

“If an authority that is supposed to protect waterways actively challenges their responsibility to do so, it’s no wonder that other water bodies without this level of protection, such as the Ashburton Lakes, are in such a perilous state.”

Rose says ECan’s dereliction of duty after the conservation order amendment “extends the water grab”, which was “first engineered by the National Government to facilitate intensive dairy and intentionally continued by ECan as a matter of political choice”.

Harking back to the Government’s language used in dismissing ECan’s councillors in 2010, certainly there have been “opportunities for water storage”.

A fair question might be, has there been enough focus on a “proper allocation plan” and “increasing problems with water quality”?

If not, could it be considered a classic win-loss?

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2 Responses to How the Rakaia turned into a pipe for irrigators

  1. W. Gregg says:

    Nick Smith and State puppets like David Caygill should hang their heads in shame. Caygill was a principal figure in the 4th Labour government’s discounted sales of the public’s assets in the 1980s. Words fail to represent my disgust.

  2. Charles Henry says:

    A long drawn out article by David Williams, but outlines completely the wanton destruction wrought first by National and now supported and continued by Labour.

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