News / Community / 15th July 2020
Rare phenomenon destroys Pilliga Forest roads
It is estimated that it will cost several hundred thousand dollars to repair an unprecedented number of deep cracks in the road network throughout the Pilliga Forest, following drought-busting rain.
The hollow fissures have damaged many access roads crucial for fire fighting in the Pilliga West State Conservation Area and Merriwindi State Forest, north of Baradine.
Measuring more than a metre deep and several metres long, the cracks have appeared due to a combination of the geology and weather conditions.
Damage has been found throughout the area including National Parks, State Forests and private property.
“The drought we experienced over the past few years completely dried out the soil profile, leaving some sections of top soil very hard and an underlaying soil layer susceptible to erosion,” said a National Parks and Wildlife Services (NPWS) spokesperson.
“We have had several large rainfall events, one with more than 60 millimetres in just one day, first in early 2018, again in early 2019 and again this year.
“This caused water to flow through cracks in the hard top layer into the underlying dispersible soils, which eroded away in tunnels and gullies.”
The NPWS spokesperson said it had counted and mapped over 350 holes, ranging from 1.5 metres to less than 20 centimetres deep.
“Even though some of the cracks are quite large, they are not easily seen until you are quite close, and we have had a few instances of the ground giving way under heavy machinery. It is very dangerous so we have closed most of the roads in the area.
“Local residents have told us that they have seen this before, but only on a small scale of perhaps one or two cracks; hundreds of cracks like this are unprecedented.
“Reconstruction of the Western Way, Brumby Road and Wangan Road has already been completed by NPWS and NSW Forestry Corporation. However, most roads still remain closed.
“We have made minor repairs, enough for a 4WD to get through in the areas we plan to conduct hazard reduction burns.”
Well-known Baradine ‘birdo’, David Johnston had a personal experience with the hazardous fissures, when his vehicle broke through a seemingly intact road surface and became stuck in an underground space where the soil had been washed away.
“The cracks had been taped off and roads were closed, but there was a small hole about a metre wide that I did not see when I pulled up to check the name of a road,” Mr Johnston said.
“I drove into it and one of the back wheels left the ground.
“The vehicle was completely stuck and if it had not been for the amazing satellite rescue system I might still be there! The ambulance had a winch and pulled me out of the hole.
“It could have been a different story if I had run into the hole travelling at 20 kilometres per hour. There is a lot of luck in life.”