Clash over mudflow threat

By JO-MARIE BROWN

The Conservation Minister and local authorities governing land around Mt Ruapehu have clashed over how best to prepare for a big volcanic mudslide expected by 2006.

The torrent of mud, ash and water - known as a lahar - would overflow from the volcano's crater lake and threaten everything in its path.

But preparations to deal with the next lahar have hit a snag.

The area's regional council, horizons.mw, and the Ruapehu District Council are objecting to the Government's decision not to do engineering work at the crater rim to drain the lake before a lahar occurs.

Instead, a $300,000 early-warning alarm system has been installed and a stop-bank built at the base of the mountain to stop a lahar from going into the Tongariro River and towards the Desert Road.

But the councils, who will be responsible for evacuating people from the area when a lahar occurs and cleaning up afterwards, say they do not have the resources for the job.

Council representatives met Conservation Minister Chris Carter to urge that engineering work at the top of the mountain be reconsidered.

"We came away pretty disappointed," regional council chairman Chris Lester said.

"If the lahar is left to occur on its own volition then the real environmental and infrastructural impact will occur outside the National Park, which is fine from the minister's perspective but not so fine from ours."

A spokesman for Mr Carter yesterday said the conflict had arisen because of "a fundamental difference of opinion" over whether work should be done at the top or the bottom of the mountain.

The Government had decided to intervene at the bottom of the mountain because "intervention at the top is just a one-off - it only fixes this lahar," the spokesman said.

Instead of looking to drain the crater lake, the Government was considering raising and strengthening road and rail bridges so lahars would flow underneath them.

The spokesman also said the Government would "look sympathetically" at requests from the councils for money to help them carry out the evacuation and clean-up.

But Mr Lester said he wanted the Government to indemnify both councils against damage or loss of life.

"We are being prevented from taking mitigating measures to ensure that that doesn't happen so we are being left exposed."

What is a lahar?:


* A mudflow made up mostly of volcanic debris.

* In 1953, a Ruapehu lahar destroyed the Tangiwai rail bridge, and 151 people died when an express train plunged into the Whangaehu River.

* Scientists say about 60 lahars have come down the side of Ruapehu in the past 150 years.