The Waiho River (bailey) Bridge from the northern bank with existing rock protection. Photo: Local Democracy Reporting/ Greymouth Star - Brendon McMahon
The rapid retreat of Franz Josef Glacier and the subsequent "huge" volume of riverbed material crawling down the Waiho Valley is a growing problem for the area.
That was a stark warning to the West Coast Conservation Board in a presentation from glaciologist Dr Brian Anderson.
Anderson said as the exposed glacial valley walls collapse, "a huge amount of sediment" was making its way into the Waiho valley and its river system.
The problem was most obvious in the rapidly aggrading Waiho riverbed.
Over time, a lot of the sediment from the glacial retreat would move down the river bed during "more intense" rainfalls, Dr Anderson said.
This would be exacerbated markedly for every degree the temperature rose in the future, and the South Westland glaciers were a barometer of what was happening with the climate, he said.
Department of Conservation Western South Island director Mark Davies said the West Coast Regional Council had statutory responsibility for management of the river.
But input on infrastructure management in the park was also needed from Westland District and the NZ Transport Agency.
With access to the glacier areas getting harder and harder, the idea of building a gondola in the Franz Josef valley was put to Dr Anderson.
He said he had no immediate opinion.
"I guess the question [is whether] to build ... an amenity area in National Park to allow access?
"A good idea or not? ...We've lost a lot of glaciers and it's getting harder to get into the mountains. What to do?"
Conservation board chair Mike Legge noted the idea of a gondola versus helicopter access had come up during the previous Westland Tai Poutini National Park plan process.
Local helicopter operators were in favour of the gondola as it would help secure the area as a visitor location.
In relation to that, Dr Anderson raised New Zealand's commitment to cut its emissions by 50 percent by 2030. "That seems to me to be the crucial question."
Davies said the gondola idea had never progressed beyond a third party proposal into a formal application.
Last year a review of the Franz Josef Special Purpose Road for the department by engineering firm WSP found the protection of it was "average to very poor" and the maintenance cost far exceeded the current funding to the Department of Conservation.
The WSP report for DoC was released to the Greymouth Star in July under the Official Information Act.
It noted the need for "a more strategic approach" to future proof it to 2040 or beyond.
Local Democracy Reporting is Public Interest Journalism funded through NZ On Air