DoC camera helps to fight Kaimaumau peat blaze

Fire control officers pour water on to the hot spots after they have been identified by the thermal camera.

The Department of Conservation has gone high-tech in a bid to extinguish an underground peat fire burning since late last month in a 250ha conservation area at Kaimaumau, 30km north of Kaitaia.

A thermal imaging camera is being used to identify hot spots burning underground in the Lake Waikaramu conservation area, habitat to rare and protected species such as black mudfish, green geckos and native orchids.

The camera has shown peat smouldering at more than 270C underneath the reserve in hot spots that appear on the surface to be no different from other ground.

Bruce Janes, fire depot manager from Rangiora in Canterbury and one of only four DoC camera operators in the country, said hot spots like those shown up by thermal imaging can lie dormant for days before a strong wind stirs them into life.

"Then they burst into flames and re-ignite unburned fuel."

Mr Janes flew over the fireground during the weekend, picking up remaining hot areas by camera and marking them by GPS before ground crews moved in to quench them.

More than six million litres of water - most of it from the nearby Rangaunu Harbour - has been pumped into the ground under the area ravaged in a blaze that destroyed 62ha of a protected habitat area soon after it broke out on adjacent private land 12 days ago.

Ryan Banks, from Forest Protection Services, said 624,000 litres of water were pumped on one night late last week to flood a section of fireground the fire crews call "The Cauldron".

Mr Banks said this area was like a volcanic cone, with intense heat and smoke coming from underground where peat was burning at more than 2m deep.

The white-hot ground had earlier made access too dangerous for firefighters to get in with hoses and heat probes, so pumps were set up to flood the area, allowing crews to work on it.

The ground now looks like a moonscape, with craters formed in blackened earth, gumhole remnants and burned kauri stumps.

Final management of the fire was yesterday passed to the Far North District Council which has two ground crews, and one DoC unit, doing final mop-up work.

"We're on top of it now," said DoC spokesman Brett Butland. "We've certainly broken the camel's back and operations are being scaled down."

The fire is the fourth major blaze on a DoC estate north of Kaitaia since January as parts of the Far North continue to go without substantial rain.

Little more than 12mm of rain fell in Kaitaia last month - about 10 per cent of the monthly average - and parts of Doubtless Bay recorded less than 20mm compared with an April average of about six times that.

In March, Kaitaia got just 5mm and Mangonui 10mm. The Northland Regional Council said most of Northland received only 5 per cent to 30 per cent of its average monthly rainfall during March.