The fringes of some Canterbury rivers have been absorbed into expanding farms, resulting in the loss of thousands of hectares of public land to private development.

The issue – known as "agricultural encroachment" – has happened incrementally over several decades, and is adding to the many pressures facing the region's internationally significant braided rivers and the rare ecosystems they host.

Environment Canterbury (ECan) research found that nearly 12,000 hectares of Canterbury's river margins had been taken over by intensive farming between 1990 and 2012.

SUPPLIED Intensive farming moving closer to the upper reaches of the Waimakariri River in the high country.

About 60 per cent of that land was developed through private land sales, but nearly one-quarter was public reserve land effectively privatised and developed.

Authorities in charge of public land all acknowledged that land had been taken and developed without permission.

None of them were able to quantify how much, and in some cases, the encroacher was allowed to keep the land after meeting certain conditions.

LINZ/SUPPLIED Development near the floodplain of the Rakaia River.

Development on the floodplain of the Waiau River.

The result had been a "massive transformation of riverbed margins" in Canterbury's lowlands, a problem now starting to spread into the high country, said Forest & Bird's Canterbury conservation manager Jen Miller.

"Forest & Bird has become increasingly concerned over what appears to be an increasing land grab of our public land in the high country for private economic use," she said



"Further, it is exacerbated by the failure of agencies such as DOC and LINZ, charged with managing this land, to act when they become aware of the illegal development occurring."

SUPPLIED A development on the Selwyn Riverbed. A local dairy farmer was served an abatement notice.

A ROAD ON THE SELWYN

Late last year, structures started appearing in the Selwyn River bed.

Among them was a makeshift road about two kilometres long, a long stopbank, land cleared for pasture, and pivot irrigators placed into the ground.

LINZ/SUPPLIED Development on the edge of the Selwyn River. The dots are cows.

After a local complained to ECan – the development was clearly visible from the road – it was traced to nearby dairy farmer Mike Dewhirst, who had allegedly expanded his farm into the riverbed, which is dry for much of the year.

After a complaint, ECan ordered Dewhirst to stop with an abatement notice. It said the work was not authorised and an investigation was ongoing.

Dewhirst did not return a request for comment.

IAIN MCGREGOR/FAIRFAX NZ The Waimakariri River after snowfall.

It shone a light on a process which has happened for decades.

While not a braided river, ECan's data showed the Selwyn had lost 400 hectares of margin land since 1990.

Collectively, the Rakaia, the Rangitata and the Waiau rivers lost around 7000 hectares, or the equivalent of 40 Hagley Parks, to development.

Encroachment into Rakaia River floodplain.

It has happened with the full knowledge of authorities, who in some case have allowed encroachers to keep using the land they took.

TAMING THE BEAST

Braided rivers are internationally rare, typically found in remote places such as rural Alaska and the Himalayas.

The majority of New Zealand's 300 braided rivers are in Canterbury, where they have become iconic, spectacular blue ribbons sweeping across the stony plains.

What makes Canterbury's braided rivers unique are their populations of endemic species, some of which exist nowhere else.

Developing the northern margin of the Waitaki River.

Among them are the kaki (black stilt), wrybill, black-billed gull and the banded dotterel, which are all threatened.

Although the margins often look scruffy, dominated by exotic plants such as gorse and broom, they are home to ecosystems of their own; Rare lizard, bug and plant species can be found on the floodplains.

Encroachment tames braided rivers, which have a notorious tendency to change course: The Waimakariri River, for example, once flowed into Lake Ellesmere, but now drains to sea near Kaipoi.

By hemming them in, the rivers start to lose their natural character, which has an impact on biodiversity.

"To maintain this diversity of habitats, the river must be allowed room to move back and forth over its braidplain, destroying and creating habitat as it goes," ECan's report said.

"When braidplain extent is constrained or otherwise modified by agricultural encroachment or engineering works, natural character is reduced, with associated reduction of habitat diversity, habitat quality and biodiversity."

Decades of encroachment has slowed by necessity. In the lowlands, there were barely any river margins left to develop.



"To some extent, this slow-down probably reflects that there is now little undeveloped river margin land left over much of the region's low plains, but some development is still continuing," ECan's report said.

It was starting to happen in the high country, where the water was still pure and the last refuges of native species lived.

Recent photos from the upper reaches of the Waimakaririri River, not far from Arthur's Pass, appear to show a farm developing right up to the river's margins.

"Most of the river margins on the lowlands that can be developed have been," Jen Miller said.

"The most urgent issue is the development that is occurring in the upper catchments of our braided rivers, which still have good quality and intact biodiversity."

Protecting the braided rivers had been a major focus for ECan, programme manager Don Chittock said.

"Braided rivers are dynamic systems that are constantly changing; the bed widens and constricts, flows change regularly and channels change course.

"Anything that affects these natural processes will have an influence on its natural character. Our challenge is to not allow degradation of this character."

ECan had taken enforcement action, including prosecutions, against people for illegally taking public land, he said.

The protection of braided rivers had its own chapter in the Canterbury Water Management Strategy (CWMS), and new rules introduced last year gave further protections, Chittock said.

"We need to be particularly aware of how land use change may impact stretches of our braided rivers in the high country, where we see a higher degree of natural character."

Ashburton farmer Chris Allen, who is Federated Farmers' environment spokesman, said it was in both farmers' and the community's interest to protect river margins from encroachment.

"Most farmers that I'm aware of respect that and they know that they need a marginal strip," he said.

"The last thing they want is a braided river to come out and destroy your land."

His own farm had modern plantings separating it from the braided Ashburton river, he said.

There were cases where volatile rivers changed course and moved closer to farms, which was why natural margins were important

"When [farmers] see the previous owners haven't developed up to the edge of the river, there's usually a reason they haven't done that - it's because they value the protection that riparian strip gives, and the rest of the community values that.

"It's in our interest to look after those because it keeps the river in a certain confines but lets it do what braided rivers do. So when it gets out we can sort of manage the damage it does to our property.

"It makes adjoining landowners quite nervous when they see certain river plantings challenged."

'FORMALISING THE OCCUPANCY'

The authorities who manage public land acknowledge cases where land had been taken without permission.

In some instances, those who privatised public land were retroactively given approval after they'd done it.

Land Information New Zealand (LINZ), which manages several million hectares of Crown land, said it was aware of situations where landowners had taken its land without permission.

In some cases the encroacher would be allowed to "formalise their occupancy," typically by being granted a licence to occupy for up to five years, with conditions attached.

"The [licence] would typically contain restrictions on use of the land, setbacks from the water courses and fencing requirements," said Acting Group Manager of Crown Property Trevor Knowles.

"If we become aware of an unauthorised occupancy, we don't allow it to continue."

All land had an associated report that identified possible uses, including lease opportunities to neighbours, he said.

The Department of Conservation (DOC), which manages nearly nine million hectares of public land, also said it was aware of its land being taken.

"DOC takes the illegal grazing or modification of public conservation land very seriously," said Eastern South Island Operations Director Andy Roberts.

"Usually the department works with the party in question to restore a modified site or come to another workable solution."

That may include setting up a lease for the activity, or even eventual ownership by the encroacher, "provided the appropriate processes have been followed," he said.

PRESSURES

It comes at a time of ongoing pressures on braided rivers, particularly the rare species that live in them.

Community groups have been tasked with contributing to their protection, supported by authorities.

The scale of the issues – including encroachment, introduced predators, high demand for water extraction, and human disturbance – is a lot to bear for groups that are largely volunteer driven.

BRaid, a community group dedicated to the protection of braided river ecosystems, helps coordinate river care groups across the region.

Because the groups are largely volunteer-driven, they often don't work as needed, BRaid chairman Nick Ledgard said.

"In many cases, those groups don't coalesce into anything more than just keen individuals," he said.

"There was one starting to tick over quite nicely in the Waiau, driven by a very capable lady, but she moved on and the thing no longer exists.

"Just having people going I'll give you a hand when I've got time ... there's no long-term continuity to that."

While improvements had been made in areas with strong river care groups, such as on the Ashley River, other braided systems were declining.

"On the Ashley River, we're in a position where we've been able to gather data for about 15 years, and therefore we can start looking at trends. What we're seeing there is an improvement.

"We suspect, or in some cases we know, it's a declining trend [on other rivers] but we don't have that continuity of long term data to put figures alongside it."

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