Protecting the River’s neck

The North Johnstone River is threatening to change course across a narrow neck of land on a farm in Far North Queensland potentially affecting water quality and availability of productive land over a large area. A low cost solution is being attempted to tackle what could be a large and expensive problem.

Not only is one of the paddocks under threat, but the breakthrough of the river could cause erosion and bank slumping for kilometres upstream. Weeds are trapping sediment and pushing water towards the erosion face which is enhancing the likelihood of the breakthrough.

hanrahans_bendTablelands Regional Council (TRC) was awarded $150,000 by the Department of Natural Resources and Mines through Terrain under the Environmental Line of Recovery Project to support the landholders in addressing the problem.

The project will trial two new methods aimed at preventing a breakthrough.

TRC’s Kirsty Lamperd said, “Work has commenced on lowering a series of point bars in the vicinity of the erosion to help deflect flows away from the neck. That involves spraying the weeds, lowering some bars with machinery and depositing waste material on adjacent land. Bars will be revegetated with native tree species to shade out weeds in future.

“Bottle brush are being planted at the toe of the eroding bank to slow it down and rocks are being placed on the top of the narrow neck of land to prevent it eroding downwards.”

Alan Dunne from Bob’s Agricultural Service who is providing support and advice said, “We will also be trialling other plants such as she-oaks and lomandra at the toe of the bank in what I expect will become a “battle of the species” to see which is best. The learnings from this planting will be applied in other projects.”

Terrain’s Waterways Coordinator, Errol Colman said, “If these lower cost bar stripping and revegetation methods prove to be successful at a difficult site like Hanrahan’s Bend they could save a lot of money in stabilising erosion at other sites. We will certainly be monitoring this project with great interest.”

Terrain and Bob’s Agricultural Services continue to provide technical support to the Council and the landholder.