Stream of consciousness

It could be said that nothing sustains life in Nelson like the Maitai River. In the first of a two-part series, Sally Kidson looks at its history and its place in the city.

A tiny silver fish with a luminescent strip down its side darts through my spotlight's beam.

"Catch that one," my guide for the evening, Martin Rutledge, says. "They smell of cucumber."

The fish is too fast, and flits off into the darkness, so we continue to wade through the Maitai's warm, gentle flow further upstream.

Our spotlight picks up a black and white speckled fish, about 20 centimetres long, nestled on the rocks.

"That's a giant bully, and a decent sized one, too," Mr Rutledge says, taking a photo of the native fish.

It's a balmy summer night and in its deeper spots the Maitai looks like slick, dark molasses flowing to the sea. Apart from the odd splash from ducks, there's nothing to suggest too much is going on below its surface.

But a spotlight reveals communities of life in the river not normally seen during the day. Mr Rutledge, a freshwater technical support officer for the Conservation Department, had previously told me it was at night time that the river "really comes alive". He wasn't exaggerating.

Even though we are in the urban area around the Trafalgar St bridge, the breadth of river life is surprising. Eels and elvers snake along the river bottom. Small shoals of juvenile yellow-eyed mullet hang out near the surface, and translucent salt water shrimp – their eyes shining like cat's-eye reflectors – lurch around near the bottom.

Native black-and-white bullies cling sluggishly to the rocks, and kokopu (a species of whitebait) can also be seen.

Shining the spotlight into some of the river's deeper pools reveals trout of different size.

And eventually we capture one of the tiny silver fish, a smelt, which, surprisingly, does smell strongly of cucumber.

Further upstream, out of the saltwater reaches, we see fresh water shrimp and the beautifully marked red-finned bullies.

We are so close to the city and it's reassuring there is so much life to see in the Maitai – one of Nelson city's most important natural features and deeply loved by its citizens.

Back in 2005 when the Nelson City Council reported on the recreational use of the Maitai River and valley, it said Nelsonians' affection "could not be over-emphasised".

"Time and time again interviewees described the Maitai as a `jewel in Nelson's crown'," the report said.

So just how healthy is this precious asset that meanders through our city?

Mr Rutledge pauses before answering the question. He is one of the many I talk to about the Maitai who say that while the river's health and water quality has declined, it is still pretty good being so close to a city.

But while the Maitai still flows between relatively natural banks to the sea, it is greatly different from the river that both Maori and early European settlers would have seen.

The native bush that graced its banks has largely gone, and pine plantations now cover much of the catchment.

Over the past 160 years the river's path, in its lower, urban reaches, has been controlled and straightened. The work is most visible in the area downstream of the Nile St Bridge, where the river channel has been narrowed and the banks made steeper to allow people to build near it. While it is mostly gentle – city council data shows its mean flow is about two cubic metres of water a second (cumecs) – it has been recorded carrying 200 cumecs.

The Maitai's mouth has also shifted progressively east as an estimated 200 hectares of the Haven has been reclaimed to create Port Nelson.

Mr Rutledge explains something else that has changed. The river's lower reaches were once rich swampy wetlands and its biodiversity now is a shadow of pre-European times.

Evoking images of exotic rainforests, he tells of a river packed with fat eels and other native fish. The valley would have been teeming with birds; at night, bats would have flitted and darted along its banks.

An early settler, quoted in an 1897 article in The Colonist newspaper, described the Maitai valley in the 1840s "as a thing to be remembered".

"On the left bank – going up stream – after crossing the Nile St bridge, was a virgin forest of large trees, and at night time one had to be wary lest he fell into one of the many sawpits."

Another early settler described the path to Pelorus through the Maitai, once the main route to Marlborough, as cutting through dense primeval forest. The scenery, he wrote, was "truly outstanding".

Fat kereru, kakapo, tui, bellbird, weka, kakariki and kaka lived in the valley. Blue duck were on the river in large numbers and kea would also have been prolific in higher altitudes.

Mr Rutledge says that at night the area would have been teeming with native bats.

The arrival of the Europeans, who introduced predators and placed bounties on some birds such as kea and shags, had a dramatic affect on native birdlife.

The valley's birds and extensive tracks of aruhe (bracken fern) and harakeke (flax) were important resources for Maori, and the river's and Haven's fish stocks were also important food sources.

But it wasn't just the rich food stocks that drew Maori to the Maitai. The hard dark stone known as argillite, or pakohe, was an important prize the valley yielded.

Resource management consultant Dean Walker says pakohe tools from Nelson have been found throughout archeological sites in the South Island and central North Island and the stone was a valuable trading commodity.

Maori worked pakohe at quarry sites along Nelson's mineral belt, and the large quarry site known as the Rush Pools is accessed through the Maitai's south branch.

How Maori shaped the stone at the quarries, using big hammer stones weighing anything from 25 kilograms to 100kg, lugged from the Boulder Bank, makes fascinating reading.

The Maitai Valley also contained the main te ara, or walking tracks, to Marlborough and Wakapuaka. Early settlers used the track to Pelorus over the Maungatapu as the main thoroughfare to Marlborough, which meant that for long periods the Maitai Valley was a main route in and out of Nelson.

Ngati Kuia resource management spokeswoman Chris Hemi says several tribes had sites in the vicinity of Nelson.

Her Ngati Kuia ancestors had more or less permanently occupied a site at Miller's Acre.Matangi Awhio, or the area now known as Auckland Point, was also a favoured site, established by chief Pohea in the 15th century.

Ngati Koata had a small village at Punawai near Richardson St, Ngati Rarua had an encampment on Haulashore Island and Te Atiawa had a camp near the Maitai mouth.

Mrs Hemi won't comment on whether the river will play a part in the upcoming Treaty of Waitangi Settlement for the region: "That's politics" she says.

But the Maitai is one of 12 rivers the Crown has offered local iwi in the future agreement.

It is the river most Nelson Maori use in their mihi (the speech used to identify themselves during a powhiri) as their awa, or river, Dean Walker says.

Or as Chris Hemi says, while sitting in the Oasis cafe on the edge of the river, keeping an eye on her grandchildren clambering on the banks: "There is no other, really."

European settlers quickly came to appreciate the river as well; there are numerous records of its place in Nelson life (including where many school children learned to swim). Several families, including my father's, owned basic baches or whares (which they pronounced "worries"), up the Maitai Valley where they enjoyed the river and its lush surrounds.

The Kidson's wooden whare was in lush beech forest not far up the Maitai's north branch. It has long since vanished under the water of the dam.

While the growth of the city has impacted on the river's health, it is the damming of the river in the 1980s to provide water for the city's growing population that has had the most dramatic effect.

Numerous people with long-term connections to the river tell of how the dam has damaged the river, making it less attractive for both swimming and fish.

Long-time Maitai resident Gwyneth Venner wrote in her book on the Maitai and its people: "There are no `crawlers' and no trout, except in the town area. It is impossible to find `tiddlers and cockabullies' or any fauna on upturned stones. The whole river is brown, not as it was, a lovely aqua-green colour with every stone to be clearly viewed from the roadway."

Research organisation Cawthron Institute has done a lot of work investigating the state of the river for the Nelson City Council. Fresh water ecologist Roger Young says the Maitai is still relatively healthy.

"There aren't too many urban rivers around that you would think about swimming in," he says.

Dr Young says the water quality and river health in the Maitai headwaters are very good, and the water quality and the clarity of the river is relatively good below the dam. But the health of the river does decline as it winds down stream.

Dr Young says one of the "mysteries" of the river is the lack of sensitive macroinvertebrates, or tiny critters like boatmen and mayflies, downstream from the golf course.

These little creepy crawlies are sensitive to pollution and are a good indication of a river's health. They also provide food for wildlife, so higher numbers correspond with healthier populations of fish and birds.

Dr Young says the water quality in that part of the Maitai is at a level where high numbers of sensitive invertebrates would be expected, but they aren't there in the anticipated numbers.

Several factors could be contributing to their absence, but monitoring has not been going on long enough to provide conclusive answers, he says.

Concerns have also been raised for the past four to five years about the levels of faecal contamination from the Riverside Pool down. The Cawthron has done trace tests of this material and has determined it is from human sources, and does not originate from stock up the valley, he says.

Nelson City Council environmental monitoring co-ordinator Paul Sheldon says a lot of work has been done in the past 18 months to clean up the lower reaches of the Maitai.

He says the problem is thought to lie largely with the old sewerage infrastructure, some dating to the 1880s, in the Trafalgar St-Collingwood St area.

"Fingers crossed, it is going to be better, but the reality is we're are in the middle of an urban area."

That largely sums up the situation: the Maitai has long been a defining feature running through Nelson and, hopefully, with careful management, it can stay that way. But there are many unknowns about the next chapter.

As development pressure creeps up the valley, the threats to the river can only increase.

One thing is certain, as a swimming trip to the Maitai with English friends reinforced this week – how much can be lost in a short time. As we looked at the river from the shallows, my friends commented they couldn't believe how clear the Maitai was.

"This is what I remember the river being like on our farm when I was a kid [15 to 20 years ago]," one said.

"But, it's all brown and dirty, and no one goes swimming there now."

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