Flood concerns as war on willows leaves major river clogged

At the bottom end of the river, where it narrows and eventually runs into the Macquarie Marshes, farmers are angry large willow rafts are altering the course of the river, creating serious erosion and even threatening a flood in Warren.

The issue was raised at the NSW Farmers conference on a number of fronts. The first concern was that the remediation work upstream is seeing willow branches and logs float down the river system. The Farmers' Warren branch wants all willow cuttings to be removed from any potential flood zone.

The other concern is once the floating timber (willow floats) arrives near Warren, nothing can be done to remove them because of laws stopping removal of fallen timber from rivers. Some fingers were pointed upstream at Molong for the dilemma but Cabonne shire says that all willows removed in remediation work are either chipped or burnt and placed away from flood zones.

Cabonne spokesman Dale Jones said "Cabonne does not allow any willows to fall in the watercourse". "We are doing extensive remediation work along Molong Creek and any willows cut down are taken away," he said.

He said there had been a case of a willow raft in the Belubula River even though no remediation work was underway.

Simon Cant, Raby Irrigation and Mumblebone, said he was concerned such was the amount of willow timber coming down the Macquarie it could eventually force the redirection of the Macquarie down Marra Creek - a deathknell for the Macquarie Marshes. The bank up of willows had helped cause serious erosion along the banks of his property at Mumblebone (see picture). A vast swathe of his paddock has been cut out by the clogged up river.

In 2016 a 800m raft of willows put Warren on flood alert and threatened its bridge (the Macquarie reached major flood level). "We had 12 or 16 government officials standing there scratching their heads when suddenly there was big crack and the willow raft split. A farmer used his digger to stop the willow logs breaking the bridge," Simon Cant said.

"At the moment we are not allowed to touch these willow logs. We understand that fallen red gums should stay as they provide habitats but we fear this build up of willow is changing the course of the Macquarie and endangering Warren when we get another flood situation. We don't want to see the river choked again."

The Farmers passed a motion for the Government to show "clearer responsibility" in managing riparian zones.

Willows, that are said to have spread from cuttings from a willow by Napoleon's grave on the Atlantic island of St Helena, and cuttings from that tree were first planted in New Zealand in 1838. Willows (there are several varieties) love conditions by the rivers and streams in southern Australia, mainly in Victoria and NSW.

It is not exactly clear when they were first introduced to Australia, but they were quickly used in colonial times to prop up banks. But although they provided shade and bank stability, their roots spread out over vast areas and choked many waterways.

The Rivers of Carbon website says that in 2011, the total area of riparian zone willows in Australia was 21,015 ha with 76 per cent in Victoria and 16 per cent in south-eastern NSW.

Councils are now busy cutting out willows all over these areas, and also Landcare groups. Landcare also a group known as Willow Warriors who pinpoint bad black willow infestations in southern NSW through kayaking adventures.

Rivers of carbon says that willows carbonise a river, making it silt up with dense roots and even strangling some watercourses, also ruining habitats of fish and water birds.

"Water movement is slowed and may be diverted around these dense thickets, causing stream bank erosion as water is diverted outside the natural stream channel," it says.

"Most willows in Australia have been classified as Weeds of National Significance because of their extensive spread and threats to stream ecology and flow. It is illegal to sell or plant willows in Australia, with the exception of Salix babylonica (Weeping Willow), Salix calodendron and Salix richardii (both sub-species of Pussy Willow)."