Opening Te Waihora: The Taumutu rūnanga is determined to preserve the traditional location of Fishermans Point.

One rūnanga proposed it, the other rūnanga blocked it. Why a combined canal scheme to clean up two Canterbury lakes disappeared from public sight. JOHN McCRONE reports.

At first blush, it doesn't seem a good look for the Māori co-governance approach to our damaged waterways.

Te Waihora, or Lake Ellesmere, ought to be Canterbury's ecological jewel – an internationally-ranked destination rather than the muddy puddle that folk skirt on their dash towards the delights of Akaroa and the Banks Peninsula.

And back in 2010, enough people agreed for a canal and weir scheme – a new controlled method of keeping the lake open to the ocean – to be a winner in a Canterbury "big ideas" competition.

The V5 contest, promoted by the Chamber of Commerce, Canterbury University and Christchurch City Council, was looking for projects that could potentially contribute $1 billion to the regional economy over 20 years.

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Te Ao Hou, as the canal project was dubbed, was one of the four selected, ranked alongside others like the Central Plains Water irrigation scheme in the judges' estimation.

It was a big deal. Ngāi Tahu's then kaiwhakahaere, Sir Mark Solomon, accepted the prize. Jokes were made about the price of whitebait collapsing with what Te Waihora would become.

A Press editorial called it the most eye-catchingly innovative of the winners.

But then, mysteriously, the idea vanished from sight. Nothing has been heard of it since.

Well, half the scheme has happened. Te Ao Hou grew out of the smaller $1 million canal project proposed by Ngāi Tahu's Wairewa rūnanga – its Little River-based hapū or sub-tribe – to deal with the nutrient pollution of neighbouring Lake Forsyth, or Te Roto o Wairewa.

That outlet has now been functioning for some years with huge improvements to water quality.

Environment Canterbury (ECan) chair Steve Lowndes, a 20 year resident of Birdlings Flat, says he gets out in his tin dingy to check on how the returning stands of healthy lake weed are winning the battle against the soupy green algae in Wairewa.

"You can look right down into the water and see to where the macrophytes bed in the bottom of the lake. The clarity is amazing."

STUFF Te Ao Hou canal project: The plan was to connect Te Waihora/Lake Ellesmere to an estuary outlet at Birdlings Flat.

Lowndes says the last step for the Wairewa side of the project – building a small road bridge across the canal – will be complete in a matter of weeks. There will be a small celebration around that.

However the 4km canal meant to hook up Waihora to the same ocean opening, creating a lush new estuary area at Birdlings Flat where the waters would meet, hasn't even got as far as the engineering feasibility study that was part of the V5 prize.

And why not? Is it – as some insiders to the iwi politics are grumbling – local tribal rivalries have been allowed to trump sensible decision making?

It is being pointed out the Te Ao Hou project would have brought great mana to the Wairewa rūnanga's side of the lake.

Both lakes would not only drain at the same point. Birdlings Flat would also become the place that enjoyed the concentrated runs of tuna, pātiki and inanga – or eel, flounder and whitebait.

However this would spell an equal loss of mana for the Te Taumutu rūnanga which occupies the southern shore of Waihora, 25km down the Kaitorete Spit at Fishermans Point, where the traditional lake opening has always been.

In Māori times, when Waihora was still an open lagoon, Taumutu was the important pā site, guarding the entrance to this "food basket".

Then as the pounding surf and shingle banks gradually closed Waihora, Taumutu took over with regular controlled openings to keep the lake refreshed and restocked by the sea.

Waihora was maintained several metres higher, close to the brim. So all it took was to scrape some trenches in the shingle with a flax stalk.

A trickle would become a flood. The weight of the water would wash out a house-sized section of Kaitorete Spit for a few days, until the next southerly blow sealed it again.

JOHN MCCRONE/STUFF Finishing touches: An access bridge being installed at Birdlings Flat as Wairewa rūnanga finishes off its canal.

For generations, the management of Waihora's ocean outfall has been central to Taumutu's cultural identity.

And so after the great public fuss of the competition win – Te Ao Hou as the clever project to clean up two lakes in one go, not to mention creating a 4km canal that could be used as a rowing venue for Canterbury – the tribal politics took over.

Te Waihora's case is special because, as Ngāi Tahu's treaty settlement recognised, neither this 200 square kilometre sheet of water, New Zealand's fifth largest lake, nor its kai, were ever sold to to Pākehā. It did not form part of Canterbury's 1848 Kemp Purchase.

The lakebed was formally returned to the tribe in 1998. Then it became also New Zealand's first voluntary co-governance arrangement under the Resource Management Act (RMA) – a flagship of the new biculturalism.

So when it came to the Te Ao Hou proposal, ECan – as the regional authority – had to share any decision making with the Te Waihora Management Board, a newly formed body representing the six Christchurch and Banks Peninsula rūnanga with connections to the lake.

And while Wairewa and other rūnanga had single votes around this table, Taumutu – reflecting its position – had three, including that of chair.

Taumutu soon expressed the view that Te Ao Hou was so much not a starter as far as it was concerned, it didn't even need to proceed to the full engineering study that Canterbury University had offered. And that has been pretty much that.

Wairewa rūnanga chair, Rei Simon, puts a diplomatic face on it.

Simon says the way the V5 competition happened – judged by the likes of former Prime Minister Ruth Richardson, dropped on Taumutu with much civic fanfare but no consultation – would have put anyone's nose out of joint.

"Quite bluntly, the rūnangas with the kaitiaki over the big lake were never involved with this scheme, never consulted in its infancy. And therefore they didn't agree it should happen. It never had universal approval."

Yet still, was it a good decision? If everyone's ambition – especially Ngāi Tahu's – is to return Te Waihora/Lake Ellesmere to the best health as soon as possible, should the location of an opening be allowed to matter?

Was it right for Te Ao Hou to be quietly dropped in a bottom drawer, never fully considered in terms of its environmental merits?

THE VIEW FROM TAUMUTU

Taumutu seems off the map. How many Cantabrians ever actually get out there?

The surprise is that it is no further from Christchurch than a trip to Birdlings Flat. Just hang a left at Leeston and jink down past a lot of crop and dairy farms to the sea.

Fishermans Point itself is a small and weather-beaten gaggle of homes on land leased from Ngāi Tahu.

I get a few friendly nods from the houses. At the end cottage, some ancient Pākehā commercial eelers are meeting up after their morning's fishing.

JOHN MCCRONE/STUFF Nature spot: The shags camp where the eelers come in at Fishermans Point on Te Waihora/Lake Ellesmere.

Down by the shoreline, the water slaps on the hulls of the aluminium boats. Clouds of butterflies rise up from the grassy path.

The shags are fat and so comfortable on their perches they don't even budge, just blink in surprise. A flock of snow-white birds – little egrets – erupts, circles a bit in the sunshine, before settling a little farther away.

I have already made a note this is the place to bring overseas visitors the next time they want to see something more than the conventional tourist spots.

I mention all this to Liz Brown – Māori mentor at Canterbury University and Taumutu's co-governance representative – and she smiles.

It does have that West Coast, out of the way, end of the line, feel about it, Brown agrees.

She was raised there with her father catching eel and flounder. She remembers the lake openings – the bulldozers wading into the surf to rake a breach – and everyone showing up for the resulting whitebait run.

"It was ferocious. You needed to tie yourself by a rope to a tractor. Although my father did it without and got hit by a big wave – lost his net and gumboots, but was more concerned about the tin of whitebait around his waist."

Brown says – as the abundant wildlife at Fishermans Point shows – Waihora might be mucky, even ill, however it is not biologically dead as some were labelling it in the early 2000s when the lake tipped over into its current pea-green and hyper-trophic state.

You can certainly eat the fish. And Waihora remains a world-class biodiversity hotspot with 165 types of bird and 45 fish species.

The "dead" tag is a dangerous perception – an excuse some might use to write the lake off as not worth saving, let alone visiting.

Yet you can see the future possibilities if Waihora gets its rail trails and wetland boardwalks – a reputation for being a healthy place. It could be the tourist eco-attraction, the economic contribution, the V5 competition flagged.

Certainly Taumutu sees itself at the start of a revival, says Brown.

The rūnanga is forging ahead with local native planting and stream restoration projects. It is even planning for possible housing growth, pushing for infrastructure in Selwyn's district plan.

"We need appropriate sewage, better cellphone coverage, and roading, so that more of our whānau can come back, live and even work, in the area."

So what about the rūnanga's rejection of the Te Ao Hou canal scheme, I ask? Was Te Taumutu actually considering the future of the lake there?

Brown replies the primary issue was about preserving Waihora's established character.

JOHN MCCRONE/STUFF Taumutu's Liz Brown: The brackish water of Te Waihora/Lake Ellesmere is central to its character.

Waihora has become something tricky – neither a saltwater lagoon nor a freshwater lake. Officially, it is classed as something precisely in-between – an ICOLL, or Intermittently Closed and Open Lake and Lagoon.

Brown says Wairewa/Lake Forsyth, is different. It has become fully land-locked with the continued thickening of Kaitorete Spit. The canal works with that because it allows fish and eel free passage without waves pushing saltwater back in.

However Waihora is traditionally mixed. "That's what makes it unique. Particularly along the spit, it is in the vicinity of 20 per cent saline." This is why flounder abound. Replace the ocean breaches with a canal and it would turn Waihora fresh.

This might have its advantages, like encouraging the macrophyte growth which would suck up the nutrients and help the water column clear. Yet it would be a conscious change to the lake's existing ecology.

But Brown agrees that shifting the location of the ocean opening is also a cultural issue. Ngāi Tahu's history matters when it comes to governance of the lake.

Waihora was a shared resource for the tribe. The other local rūnanga had their spots around its edge, she says. "They would come over and have their temporary sites – their wakawaka, or designated areas."

Although of course, Brown adds, that was before Pākehā settlers drained Waihora down to its present 1m or so to reclaim farmland. The shoreline used to be much closer to Christchurch.

Tai Tapu – the sacred shore – was called that for a reason. "The lake was 4m high then. So Lincoln was probably under water. And Motukārara – motu means island."

Anyway, the customary position of the opening at Taumutu is something basic to the rūnanga's identity even within its own iwi. So yes, it does count.

And besides – getting back to the science – Te Ao Hou was never the magic bullet solution some are making it out to be, Brown says. At best, it was only ever part of a package of possible clean-up measures.

But go talk to ECan, she says. They will be better placed to explain the technicalities of that.

ECAN'S POSSIBLE SOLUTIONS

At ECan, the very mention of Te Ao Hou produces a slight impression of panic stations. A flurry of texts and emails fly in all directions. Clearly it is a touchy subject.

DAVID HALLETT/STUFF ECan chair Steve Lowndes: A ticklish subject, but why shouldn't the Te Ao Hou scheme be open to debate?

However ECan's Lowndes – who is also co-chair of the Co-Governors of Te Waihora/Lake Ellesmere – agrees to meet, along with Dr Tim Davie, ECan's chief scientist and resident Waihora expert.

They are conflicted. Eager to explain the possible benefits of Te Ao Hou, nervous about saying why it isn't actually on the table for debate.

Lowndes admits he thinks it probably ought to be. "But when I've asked questions about this, I've just been told … good luck."

Davie starts by saying Brown is correct from an environmental point of view. Waihora's problems are complex, so the solutions will be too.

An easy misconception is that the purpose of a permanent canal opening is simply to "drain off all the bad water", solve its nutrient build-up that way.

However the phosphorous in Waihora sits in the thick sediment of the lakebed. A canal won't change that, Davie says.

And the nitrate leaches into the lake from its intensively farmed catchment that stretches all the way back to Hororata and the Canterbury foothills.

Given the time it takes for this to seep through the groundwater, it will be arriving at Waihora for decades.

"There's stuff in the post. The legacy of the last 150 years is still working its way through," Davie says.

So the main advantage of a controlled lake outlet would be that Waihora could be safely maintained at a greater height.

Its surface is a vast sun trap. Deeper water would keep it cooler. From there, the lake ecology could tip back towards the lake weed rather than algae, and even the toxic cyanobacteria blooms.

Davie admits ECan would like a controlled outlet for health and safety reasons too. The current business of bulldozers ploughing a break in the surf is a management nightmare.

Then ECan is also responsible for the flood concerns. In the winter of 2013, heavy rain saw Waihora rise. But for a week, the southerly made it impossible to open the lake for relief. "We had a lot of criticism over it because people's paddocks were flooded."

Environment Canterbury Diggers break through a shingle bar to open Lake Ellesmere to the sea.

Davie says people have tried and failed to create a permanent opening at Taumutu. However the exposed shingle gives no anchorage.

"There was a trial at one stage of having a concrete culvert. But it soon got smashed to pieces."

Hence why Te Ao Hou was welcomed as the clever alternative. The Wairewa outlet is stabilised by the rocky outcrops at the start of Banks Peninsula.

Yet Davie says running a higher lake is only one possible measure. If the long-term focus is the health of the lake, there are many other things to think about spending public money on.

One step often suggested is dredging. Simply suck out the phosphorous silt. But Davie says get out in the middle, appreciate how vast an area it actually is, and it becomes obvious that would be prohibitively expensive.

Another answer is to cap the sediment with a layer of a binding mineral like alum. A dusting on the lakebed would keep the phosphorous locked.

But while it has worked for small lakes of about 2 hectares, it would take investigation to show it could be effective for Waihora, says Davie.

The big project that is being trialled is using floating booms to encourage the return of the lake weed.

SUPPLIED/ECAN Wave barrier: One funded project is these floating booms to stop wind churning the lake, letting the weed regrow.

Two 100m-long barriers made of floating logs have been constructed. The idea is that these will stop the waves churning the shallow water, giving the weed a better chance to establish.

Davie says it is too soon to tell how well these will work.

Then, he says, there is the nitrate issue to remember. Here, wetlands look a large part of the answer.

When the co-governance plan for Waihora was drawn up in 2011, it included grants for many localised wetland restoration projects. Nitrates could be intercepted, turned into plant growth, before making it into the lake.

A next step would be to expand this all around the lake by getting farmers to retire land at its edge, or buying it back with public money if necessary.

Davie says if the future is bike paths, eco-walkways and bird look-outs – why not an extension of the Little River rail trail right around Waihora? – then the pay-back of this starts to look more reasonable.

Lowndes says ECan wants to put a greater emphasis on Canterbury's biodiversity values. That would be another reason for funding a larger wetlands programme.

So if there is the will, it needn't take generations before Waihora sees some real improvements, he says.

THE PLAN MAY YET LIVE

But back to the ticklish subject. Shouldn't Te Ao Hou have at least been studied? Again the conversation turns careful.

Davie says it is worth remembering that bicultural co-governance is still a new and evolving thing.

He notes the original rūnanga-level management board has now been disbanded – at Ngāi Tahu's own initiative – and replaced by a stakeholders body, the Te Waihora Co-Governance Group.

The iwi-appointed representatives, like Liz Brown, share the table with ECan and the local other councils. So there has been a strengthening of structures, Davie says.

It is also a fact the V5 competition happened just before the earthquakes, he says. That was another reason Te Ao Hou ended up on the back-burner. Too much else was going on.

However Davie says cultural values are recognised under the RMA. They are a legitimate part of the co-governance arrangements.

And more than that, ECan's general ethos has been to make a shift towards local-level decision-making within a framework of regional-level goals.

The water zone committees are exactly like that when it comes to irrigation decisions. A farming community such as Ashburton can say it has a cultural character to protect too. "It's all about local involvement and working collaboratively with people."

SUPPLIED/ECAN Raking a breach: The bulldozers in action at Taumutu, carving a channel to the sea.

So this gives another dimension to biculturalism, Davie says. Co-governance doesn't just halt with Ngāi Tahu's iwi-level view of Waihora. It has to get right down to deal with the concerns of the rūnangas. And if Taumutu says Te Ao Hou is out, those wishes count.

"Te Ao Hou is an interesting thing to look at. But it's not just a water quality issue. It's not just an engineering project."

Lowndes says management of the lake does have to reflect a balance of interests.

"And the brackish nature of the water, control of the opening, fish passage – these things are very real for Taumutu. They would find losing those elements of their mana over the lake very difficult to cope with."

So that is that? Well maybe, Lowndes grins.

In fact the first phase of the Whakaora Te Waihora programme, with its funded projects, ended in 2017. The next phase – which will be seeking money from a hopefully more receptive government – is just getting going with its workshop planning, he says.

And ECan now has a computer model of Waihora – its lake chemistry and water flows. It is going to be much easier to plug in the various control steps and see what produces the most bang for buck.

Lowndes says cultural sensitivities would probably still rule Te Ao Hou out. But who knows? More of a case might emerge for it.

"It sounds like something which should be brought up. Throw it in and see what happens," Lowndes says.

The opportunity of a public discussion is arising again. Maybe watch this space after all.