New Zealand's large, fragile mountains face twin threats

Monday, 8 August 2016

A tourist takes a photo of Aoraki/Mt Cook.

They may look like colossal slabs of rock, but experts say New Zealand's tallest mountains are in a fragile state.

Record-droves of tourists don't pay an entry fee, but leave waste that has to be removed by helicopter, while an increase in rockfall avalanches has caused house-sized boulders to tumble from the Southern Alps.

Department of Conservation director-general Lou Sanson addressing the Sustainable Summits conference.

The country's top conservation boss said the threat of an earthquake beneath the mountains kept him awake at night.

The risk of irreversible damage to the Southern Alps was discussed at the Sustainable Summits conference at Mt Cook on Monday.

* 4.5 million international visitors by 2022

* DOC may charge visitors to enter national parks

* Half a million visitors to Aoraki/Mt Cook

* National parks feeling ill-effects from tourism boom

* Mt Cook conference to help reduce user impact on NZ's mountains**

Speakers concluded there were serious pressures facing the mountains on various fronts.

Department of Conservation (DOC) director-general Lou Sanson said his organisation faced many challenges in the years ahead, but chief among them was the likelihood of a large earthquake from the alpine fault, which snakes beneath the spine of the Southern Alps.

With a 30 per cent chance of a large earthquake in the next 50 years, it presented both an ecological and economic threat.

'The issue for DOC is that most of our tourism and most of our mountains are centred along the fault. The failure will be catastrophic,' Sanson said.

'You've got to think aftershocks, massive slip events in the mountains, loss of huts, swing bridges . . . We've got to think how we work as a country to deal with this.'

The communities that would be most affected by an earthquake, such as Franz Josef, were too small to finance the costs, he said.

It could also accelerate another recent phenomenon in the alps: rockfall avalanches stripping debris from the faces of the mountains.

Principal scientist at GNS Science Dr Simon Cox said the frequency of rockfalls on the alps had increased 'exponentially' in recent years. It was not clear why, but it appeared to be a natural process.

Boulders the size of houses had fallen from the mountains, and some DOC huts were threatened by future slips, including the popular Mueller Hut at Mt Cook, which had 3000 visitors a year.

'We've had a massive increase in rock avalanches, but they're occurring naturally,' he said.

'The question is, if you hit it with a big earthquake, what's going to happen?

'It'll give the alps a hell of a rattle, and it will knock a lot of them down.'

This year, it took two hours for the DOC huts on Milford Track to become fully booked for all of January.

Aoraki/Mt Cook National Park will soon have 500,000 visitors a year, up 233 per cent from 150,000 two decades ago.

Sanson said that a few years ago, DOC did not reference tourism in any of its planning documents, but now considered itself at the core of the multi-billion dollar industry.

The rapid increase in tourists visiting once secluded parts of New Zealand presented challenges, he said.

'We've got to find this balance between our wilderness values and increasing tourism, and the predictions of New Zealand going to 5.5 million tourists [each year] by 2025.'

New Zealand was one of the few countries that did not charge for access to national parks, which was part of its heritage, he said.

He favoured a differential charge – in which New Zealanders would get a large discount for access to national parks – but said it was a political question for the Government to decide.

The 3000-kilometre Te Araroa trail, which runs the length of New Zealand, was an example of how cheaply visitors could access New Zealand's native areas.

'There are 500 people walking through New Zealand on a $90 hut pass, and we're having to face the costs of flying out all the human waste – it really doesn't stack up,' Sanson said.

'The walkers are paying on average about $3 a night. We've got to work out how we deal with these models.'