Pushing s… uphill: A tiny town’s giant waste problem

Saturday, 18 May 2024

A narrow road curls around the harbour. The water is strikingly blue against steep, brown hills. Swanky holiday homes peek over the cliffs.

This unassuming road cuts through a rich vein of Te Wai Pounamu’s history. Above it is Green’s Point, where the British first demonstrated sovereignty over the South Island, fending off French colonisation. Beside it is the spot where cattle stepped onto the Mainland for the first time.

And where the road ends is a graveyard; the site of a brutal massacre, one of the worst in this country’s history.

This beautiful corner of Banks Peninsula — imbued with grief, trauma, and historical resonance — is currently home to one town’s waste.

For half a century, Akaroa’s wastewater has flowed into a treatment plant hidden by bush. Here, the waste is treated and discharged into the harbour. Signs warn that shellfish should not be collected; no-one should swim. Wise advice, given the puddle of muck beneath a small, white pipe on the rocky shoreline.

The council has spent 17 years trying, and failing, to move Akaroa’s waste away from such a culturally sensitive site. It considered pouring it into the open sea through an underwater pipe, or trucking it over the volcanic hills to Christchurch. It investigated injecting it deep underground. It even thought about treating it so thoroughly it could be put back into the water supply. A closed loop: water in, water out.

The damage done

The story of this dirty problem begins here, at Takapūneke, where the current sewage plant sits.

It was once a thriving kāinga. One morning in 1830, the brig Elizabeth — a European trading ship — cruised into the bay to trade flax.

Ngai Tāhu’s upoko ariki (top chief), Te Maiharanui, and his whānau were invited aboard. They did not return. Throughout the day, more men from Takapūneke went aboard and didn’t come back.

Overnight, a Ngāti Toa war party led by Te Rauparaha surfaced from the ship and set Takapūneke ablaze, killing or enslaving everyone in sight. The death toll was at least 100, but potentially much higher.

The involvement of the Elizabeth — captained by a Pākehā named John Stewart, who had agreed to hide the Ngāti Toa men — in an inter-tribal dispute was scandalous. In response, James Busby was appointed the British resident of New Zealand, which led to the creation of the Treaty of Waitangi.

Takapūneke is perhaps the most significant historical site in the South Island. Some have argued its national significance rivals Waitangi.

That didn’t stop the sewage plant going in 60 years ago, with a landfill added later.

It was grievously offensive to local Māori, who considered the area tapu. But they held no political sway: “Our people had no voice really to stop those things from happening,” former Ōnuku Rūnanga chairman George Tikao said in 2010. They simply had to endure the insults.

In the 1990s, authorities proposed subdividing the rest of the land for housing. The insults had become untenable.

Historian Dr Harry Evison had been studying Ngai Tāhu history, and learned about the slaughter at Takapūneke. He, like others, was affronted by the location of the sewage plant.

“This, together with a nearby rubbish dump, must surely rank as the ultimate in modern cultural oppression,” he wrote in a 1995 article for The Press.

“Imagine a Māori sewage treatment works being constructed on top of a European cemetery”.

Evison’s article drew attention to the rūnanga’s angst. In 1998, the local council listened and apologised for its historic actions. The landfill was capped and the land became a reserve.

In 2007, the Christchurch City Council — having inherited the wastewater plant when it absorbed the old Banks Peninsula District Council’s assets — pledged to move it.

Where? It could not say.

This simple act of undoing a historical insult has become a convoluted mess.

After many fits and starts, the city council has applied for a new sewage scheme. It is likely to cost more than $100m — around $100,000 for each property connected to it. In the proposed Long Term Plan, which sets out spending for the next decade, it is one of the biggest capital projects.

This week, council staff mooted expanding the scheme, combining it with a wastewater scheme at neighbouring Duvauchelle — itself the subject of a prolonged and controversial process.

In Akaroa — permanent population around 800 — the new scheme has been controversial, even though the cost would be funded through general rates.

During recent Long Term Plan hearings, a procession of community members urged the council to reconsider.

They included the Akaroa Civic Trust, which said the council “does not have a mandate from the community” to pursue the scheme as designed. The Akaroa Ratepayers’ Association called it a “staggering amount of money” and “not what the people of Akaroa want”.

Another likened the scheme and the controversy around it to a “dark cloud…looming over our community”.

The council, in some ways, has been pushed into a corner, between the beautiful harbour and its bloody history.

Can it find a pathway through?

The data problem

The rugged hills around Robinson’s Bay are an anomaly in Canterbury.

Unlike much of the province, green remains absent from the landscape’s beige palette. Irrigation has not prospered here due to the hostile geography; it is old-school, bone dry sheep country.

There may soon be an exception. The Christchurch City Council’s plan is to take waste from Akaroa, pump it uphill to a treatment plant, pipe it5km to Robinson’s Bay, store it on a hill in giant tanks and irrigate it onto native bush.

Some waste will be kept in the township and reused on the local sports field; An attractive wetland, complete with walkways, will be used for emergency overflows. The waste would be treated to a much higher standard than at the current plant, which periodically spills sewage into the harbour.

This elaborate concept took more than a decade to plan. When the council first proposed the uphill solution, it also applied to continue discharging treated wastewater into the harbour, despite objections from the Ōnuku Rūnanga.

Alongside Ngai Tāhu, the rūnanga fought against the continued discharges. Their opposition was successful: No matter how well it was treated, putting wastewater directly into the harbour was culturally offensive.

The hearing commissioners’ ruled the council had not adequately considered alternatives. A new treatment plant and pump station were approved, but the discharge consent was not.

So, the council went back to the drawing board. In 2017, it presented five proposals to the community. They included several land-based disposal options, and a “purple pipe” option, allowing wastewater to be reused in the community. The latter received overwhelming support.

That was when a significant — and embarrassing — oversight was revealed.

While investigating the “purple pipe” option, the council noticed a problem with its wastewater flow data. Its meter was faulty — it had been drastically understating the amount of water in the network. The schemes the council had put out for public consultation would be too small.

The council had, in fact, been made aware of the faulty meter years earlier. In 2010, during the first round of work on the scheme, consultants sent a technical memo to two council staffers.

“It is understood that the flowmeter is faulty and the readings are likely to be inaccurate,” they wrote. “CCC is working with the flowmeter supplier to re-calibrate the flowmeter.”

The error meant the council had no reliable data. It apologised to the community and, once again, reworked its proposals.

It returned in 2020 with four options, this time drawing on two years of (accurate) flow data. Three involved land-based disposal, and the fourth was to continue discharging to the harbour through a longer pipe.

Again, submitters prefered the water-based option. But Ngai Tāhu made it clear it would not support a harbour outfall, which was “incapable of promoting the cultural well-being of the affected community”.

And so the council forged ahead with its preferred option, in which waste would be irrigated onto farmland near Robinson’s Bay.

It spent millions of dollars buying two pieces of steep terrain with spectacular views of the harbour, where it would drizzle the town’s waste. It commissioned trials to test whether it could be used to fertilise native trees (the answer was yes).

With each iteration, the budget rose. The 2016 long term plan set aside around $35m. The 2020 one set aside $60m. The next one proposes putting aside $93.5m, not including money already spent.

In late 2023, the council filed its official application to ECan — a meaty tome, nearly 1200 pages long. After 17 years, a resolution to Akaroa’s expensive, convoluted sewage saga appeared to be at hand.

The overflow problem

“Pumping shit uphill is never sensible, is it?”

Suky Thompson gets straight to the point. She lives at Robinson’s Bay, and is a member of the Friends of Banks Peninsula (FOBP) group, which has been a watchdog for the council’s evolving wastewater plans.

The group has produced piles of reports, attended dozens of meetings, sat on working groups and presented to the council at every opportunity.

“It has really dominated the lives of a whole lot of people,” Thompson said.

“There’s a whole group of us involved in this, and we have worked really hard. It’s disappointing when you have to do the council’s work for them.”

The group has many criticisms of the proposal. But its core argument is this: The scheme is too small, meaning there will be overflows into the harbour — the very thing it was supposed to prevent.

“It’s not going to work,“ Thompson said. “The council has underestimated the volume of wastewater they have to deal with. They don’t have enough land, and they have to store the wastewater in storage tanks in winter when it’s too wet to irrigate.”

A quirk of Akaroa’s wastewater system is its high levels of “inflow and infiltration” (I&I). When it rains, water gets into the pipes, greatly increasing the amount of wastewater to deal with. More rain means more wastewater.

The treated waste cannot be spread onto paddocks when the ground is saturated, meaning it needs to be stored. Heavy rain is a double whammy: More water to deal with and no method of disposal. Without enough storage, spills are inevitable.

The council wants to lower the amount of I&I to 20% of the total flow (down from around 60%), but after a $4m programme, the results are mixed. The average I&I across the last 5 years was 24%, but that included a drought year. In 2023, I&I was 39% — well off target.

Whether the scheme will sufficiently handle the amount of wastewater, then, is a matter of dispute.

In 2020, the council commissioned engineering firm Beca to model wastewater flows through the scheme. Due to the previously faulty flow meter, it only had two years of measured data to work with. Its results showed the scheme could handle almost all of the expected wastewater.

Then it rained. A lot. In July last year, Akaroa had its largest one-day rainfall ever recorded. Scars of dirt dotted sloping farmland across the peninsula. Water pooled in paddocks.

Dr Brent Martin — a data scientist and FOBP member — decided to rerun Beca’s modelling, adding in the recent wet years.

His results showed the council’s scheme would not have handled all the wastewater. Last month, Beca updated its modelling, which agreed — wet years meant the scheme would produce approximately 11 to 21 overflows over the next 50 years.

Since at least 2015, the council had been looking for a system that would avoid the culturally offensive practice of discharging waste to the harbour. After nearly a decade of work, it is left with a proposal would still lead to that outcome, albeit less frequently and with less noxious waste.

Ōnuku Rūnanga has supported the proposal up until now, but declined to comment for this article. The council said it could not answer whether its plan adequately addressed cultural concerns, but defended the scheme as environmentally sensible.

“We have never claimed the new system will eliminate all wastewater overflows in the Akaroa network, or the managed release of treated wastewater,” said acting head of Three Waters Gavin Hutchinson.

“There are currently about five releases of raw sewage from the Akaroa network each year. The infrastructure upgrades for the new system will bring this down to about once every 5-10 years.”

The council had included input from a wide range of experts, and followed extensive community engagement and consultation, Hutchison said.

“We believe that the high level of treatment proposed means that the actual environmental effects on soils, surface water and harbour water quality will be significantly less than the current system and the feasible alternatives, which is why we are progressing with this option.”

Pumping s… uphill

Even after 17 years, this unusually bumpy journey has some way to go.

Councillors will decide whether to sign-off the Long Term Plan and its $93.5m budget for the Akaroa wastewater proposal. ECan has publicly notified the council’s application, allowing yet another round of public input. There is no guarantee it will be signed off; there does not appear to be a Plan B.

For the FOBP, the sensible move is to stop now. If the council is wrong, it could be headed for disaster — streams loaded with nutrients; more waste in the harbour; costs spiralling out of control.

“We’ve asked [councillors] to cancel the funding, because we don’t think they can stop the snowball rolling,” Thompson said.

“It’s set up to fail.”

The group has proposed an alternative: Aggressively fixing the I&I, and improving the re-use of treated wastewater.

Even then, a harbour outfall may be required in emergencies. It is, simply, an extremely difficult place from which to remove waste.

By the time a decision is made, the sewage plant at Takapūneke will have turned 60 years old.

A memorial now sits atop the hill, overlooking the harbour, the massacre site, and the old sewage plant, which still pumps waste into the twinkling harbour, over a rocky shore riddled with grief.