When a bushfire tore through Cobrico in Victoria’s south-west igniting the peat bog underneath, toxic levels of carbon monoxide caused the temporary relocation of 20% of residents and those in surrounding areas. Peatlands cover about 5% of the earth’s surface and when ignited require trained and experienced firefighters to extinguish them due to the challenges of dealing with underground combustible material. Flooding is the only workable solution.
The fire that tore through Cobrico, a small dairy town in Victoria’s south-west, burned over 15,000 hectares of land in a peat bog. Made up of organic matter such as leaves, grass and root systems decaying over thousands of years, once ignited, peat burns similarly to briquettes; it burns at a high heat releasing smoke and unseen toxic fumes. Fine particles, water vapour, and gases including carbon monoxide and nitrogen oxides are just some of the by-products of peat fires. They are a challenge to manage as they require a significant amount of water running continuously through them to extinguish effectively. If left to burn, they can burn for months or even years spreading through the organic matter up to 10m below the surface, potentially damaging prime farming land.
Bringing water to the peat fire
Firefighters worked day and night using fire trucks, helicopters and bulldozers to try to contain the expansive and unrelenting fire. After more than a week using these traditional but futile methods, a decision was made by the local authorities to flood the area using large volumes of water. In consultation with the State Emergency Management Victoria, a plan was devised.
The then State Emergency Management Commissioner Craig Lapsley said, that with no decent rainfall on the horizon, an above-ground temporary pipeline was deemed the only feasible way to get a constant and significant amount of water onto the peat fires in a short time. ‘One of those is to put above-ground piping to bring [water] from a major reticulation main – it’s quite extensive but necessary without rain,’ Mr. Lapsley said. After careful consideration of the pipeline options available to bring in this water, large-diameter layflat fire-hose was chosen as the most efficient and economical option.
Installing the solution
The temporary pipeline was assembled using flexible layflat hose from Crusader Hose, which was supplied on reels of 200m plus some shorts. The prime contractor was Agmek from Ballarat who had the hose and pumps available. Mike Jones and his team had the hose and reel systems rapidly and efficiently transported to site in only three truckloads. Due to its compactness, the full 4km of hose was unrolled and in situ within one and a half days. The water was soon flowing through at 50 litres per second at 10 bar pressure and this rapidly contained the fire behind an inactive edge. One expert said such a feat using traditional rigid pipes would ordinarily take weeks. It is understood to be the first time such a method has been used to fight a peat fire in Victoria
The 8in layflat hose was easily connected to a valve in the Major Ottway Pipeline 4km away and this brought water to the peat fire in just 48 hours. Water was being pumped 24 hours a day alongside roadsides and across paddocks until it reached two dams dug at the edge of the peat fire at Lake Cobrico. Irrigation pumps from the dams then fed water cannons which directly attacked the fire. The water was also used to flood a trench which acted as a fire break.
Once the layflat hose and pump were installed, roads were reopened without obstacles as the hose had been placed in culverts at crossings and ran alongside. The layflat hose was deployed with minimal environmental impact and a soft footprint. Residents were permitted to return with health risks significantly reduced.
Francois Steverlynck, Managing Director of the Australian-made Crusader Hose, said, ‘We also manufacture 12in layflat and this is used by the open-cut iron ore mines in Western Australia. They use it to rapidly deploy after the cyclones fill in the pit, so the water can be pumped out and mining operations resume with minimal downtime.’
Mike Jones, the prime contractor added, ‘The key to handling large diameter hose is to have a good reeling system. Fortunately, we had the reels and drive unit in our yard so we could respond immediately. Once the fire had been extinguished, we were able to easily roll up the hose back onto the reels, ready for our next pumping project. The hose and reel system built by Crusader Hose is a great showcase of Aussie engineering!’
In conclusion, Francois suggested that this capability could also have been used for the Hazelwood coal mine fire as conditions were similar.
For more information, go to www.crusaderhose.com.au