Kaipara Harbour as seen from nearby Shelly Beach.
Photo: RNZ / Peter de Graaf

An ambitious project to clean up New Zealand’s biggest harbour is just weeks away from cracking the milestone of planting its two-millionth tree.

Kaipara Harbour Remediation (KMR) is a project of dizzying numbers – a total budget of around $200 million, of which $100m is from government coffers; 1,880,000 trees planted as of the end of June; 800km of waterways fenced off; and more than 700 private landowners involved so far with another 300 keen to get on board.

The Kaipara Harbour’s sprawling 600,000-hectare catchment reaches almost as far north as the Bay of Islands and south into the fringes of West Auckland. It’s a key nursery for snapper, a hugely important species for both commercial and recreational fishers.

But some of the other numbers make grim reading, in particular the 700,000 tonnes of sediment washed off the hills and into the harbour each year.

That’s an estimated seven times higher than before the Kaipara’s great kauri forests were cleared, and equates to a ten-tonne dump truck of dirt tipped into the harbour every eight minutes.

Parts of the harbour routinely fail water quality tests and locals are increasingly concerned about “zombie fish”, their nickname for snapper with mysterious symptoms that include lethargy, sunken eyes and wasted flesh.

Ross and Eleanore Webber, who run a 200-hectare beef farm at South Head, north of Helensville, are among hundreds of landowners already making a difference to the harbour’s health.

They have so far protected 30 hectares with QEII Covenants, a figure that will soon rise to 50ha, and planted along streams, in wetlands and steep gullies.

The QEII Trust has helped pay for deer fences to stop South Head’s infamous herds of feral deer mowing down freshly planted trees and regenerating forest.

Ross Webber said his original motivation for protecting the remaining pockets of bush on his farm was economic, not environmental.

“Initially it was to stop my cattle heading off into the bush in the afternoon and defecating there in the shade. The subsidies had come off fertiliser and it had become prohibitively expensive. I had this realisation that I was losing so much nutrient out of my paddocks, so I started fencing off the waterways about 30 years ago to keep that nutrient where I wanted it,” he said.

Landowner Ross Webber
Photo: RNZ / Peter de Graaf

It didn’t take long before the bush started regenerating and birdlife returned.

“When I saw the rewards from protecting those areas it became, honestly, an enjoyment thing as much as anything.”

Like anyone who’s lived beside the Kaipara for decades, Webber has seen the harbour’s decline.

“When I was a young man, you didn’t have to go far for a feed of snapper. I grew up with stories about how the snapper would be right up the creeks to Helensville, they’d have their tails out of the water just ferreting out cockles and pipis along the mud banks. But gradually, as I grew up, there was a huge decline in the snapper fishery within the harbour. You had to go further and further to get a good feed.”

Webber said he was now seeing snapper return to the harbour’s furthest reaches. He believed waterway planting was one factor; another was a rule protecting māui dolphins that had forced trawlers to stay four nautical miles off the Kaipara coast.

“The fishing’s done a full circle over the 60 so years that I’ve been around here. That’s a really pleasing aspect of it. The Kaipara Harbour is a nursery for 90-plus percent of the snapper fishery, so its importance to the whole of New Zealand economically is huge.”

Restoration of the waterways and hillsides on the Webbers’ farm is ongoing, with thousands more trees, shrubs and grasses put in the ground during two community planting days late last month.

Photo: RNZ / Peter de Graaf

‘It’s inspiring’

Many of those taking part had answered a call from Conservation Volunteers New Zealand. They included churchgoers, international students, and individuals from as far away as South Auckland.

Endre Wasbo, an engineering student from Norway, said he wanted to “give something back” to New Zealand.

“It’s inspiring to me seeing all these people volunteering and coming together, and also that the landowner is wanting to do this. It’s a great thing, really.”

Seiaiga Asiata, from Manurewa, signed up for the planting day on the Volunteering New Zealand website, and was surprised by how much she enjoyed it.

“I didn’t think I’d be getting down and dirty like this in the weekend, because usually I’d just be at home. But this is such a nice change for me, and it’s a great way to give back to our environment and our country. I feel so proud of myself because I’ve never gardened in my entire life,” she said.

Nathan Burns, of Conservation Volunteers New Zealand, with kohekohe seedlings ready for planting.
Photo: RNZ / Peter de Graaf

Dillon Blair, a coordinator for Conservation Volunteers New Zealand, said the planting focused on pioneer species such as mānuka, kānuka and tī kōuka (cabbage trees), with secondary species such as kohekohe and pūriri to add diversity as well as food for fruit eaters such as the kererū.

He said the strengths of KMR included its focus on private land, and the way it brought so many different players together.

“It’s private landowners, it’s hapū and iwi groups, it’s organisations like ours that are able to connect the wider Tāmaki Makaurau population to get out in places they might not have seen before. A lot of people haven’t been to South Head and seen the crazy, beautiful landscape here, or had a chance to grow a forest that will outlive them and their children,” Blair said.

Auckland University history student Emily Lloyd at work on the Webber farm.
Photo: RNZ / Peter de Graaf

Restoring the mauri

KMR pou tātaki (chief executive) Justine Daw said the project, the biggest harbour restoration ever attempted in New Zealand, was set up in 2020 by the Ministry for the Environment, Northland Regional Council and Auckland Council, along with iwi groups Ngā Maunga Whakahii o Kaipara, Te Rūnanga o Ngāti Whātua and Te Uri o Hau.

Kaipara Moana Remediation pou tātaki (chief executive) Justine Daw.
Photo: RNZ / Peter de Graaf

Its aim was to restore the mauri, or life force, of the harbour.

“It’s a really special place. It’s the largest natural harbour in the Southern Hemisphere and one of the largest harbours in the world. Everyone’s in this together to protect and restore this wonderful harbour.”

The largest share of KMR’s funding, $100m, came from the government’s Jobs for Nature Fund, with $10m from each of the two councils, and $80m from landowners, conservation groups, philanthropic and commercial partners, and “anyone and everyone who wants to support the project”.

Despite a change of government since the project started, Daw said funding was secure through to February 2031.

“We’re really grateful for that ongoing support. It’s important mahi that we’re doing here.”

Seiaiga Asiata, from Manurewa.
Photo: RNZ / Peter de Graaf

Initially KMR focused on restoring wetlands, and fencing and planting along waterways.

“There’s about 8000 kilometres of tributary flowing into the moana so that was a good place to start. But this winter, we’ve scaled up across the whole landscape. Now we co-invest in other projects like assisted native regeneration – basically fencing off areas, retiring very steep eroding hillsides, and allowing them to come back into native bush. We also plant up on eroding hillsides, to keep those precious soils where they should be. Ultimately, the goal is to keep sediment out.”

While sediment had always washed into the Kaipara, it was currently occurring at seven times the natural rate.

“That’s 700,000 tonnes a year of sediment flowing into the waterways and into the moana. It’s too much. It’s already having quite a significant impact. If our waterways are degraded, we can’t play in them, we can’t swim in them, we can’t drink from them, we can’t collect food from them. And that’s a problem for anyone who lives in the Kaipara Moana catchment.”

KMR’s goal was to halve the amount of sediment washing into the harbour within 10 years.

Daw described sediment as a “master contaminant”, because when soil washed off the land it carried other pollutants such as heavy metals, nitrates and phosphates.

“But it also just smothers life. Suspended sediments stop light getting into the waterways, and that means no food for our fish, our sea grass meadows, and the many special species that can’t survive without it. So it’s essentially starving the ecosystem.”

Daw said the Webbers, who had planted more than 20,000 trees this winter alone, were doing “an amazing job” – not just by transforming their own land, but also by bringing their neighbours on board with the KMR kaupapa.

She said 700 out of the estimated 1500 landowners in the Kaipara catchment were already actively involved, and in June the 1000th landowner had made contact to find out about joining up.

She expected the number of trees planted would reach 2,000,000 this month.

Webber said seeing the changes on his farm were “very gratifying”.

“It’s a win-win for the farmer, the land and the harbour. If you’re going to look after the Kaipara, you don’t start at the harbour’s edge. You start up these catchments right at the head of the valleys, and work your way down. And that’s happening. It’s awesome.”