Remedial works for eroding riverbank

AN INNOVATIVE technique implemented by NQ Dry Tropics will prevent more than 5000 tonnes of fine sediment a year from impacting the Great Barrier Reef Lagoon.

The work, which will begin this month, aims to remediate an eroding river bank on the Burdekin River west of Home Hill.

Using the “timber pile field” technique that is new to the region but common throughout Australia, multiple rows of timber piles will be driven into the riverbed and bank, to effectively rebuild the natural riverbank over time.

Timber pile fields slow down water to better protect eroding or at-risk riverbanks, and also trap sediment, helping to build the area up to support vegetation that can eventually replace the piles as the bank’s protection.

NQ Dry Tropics Civil Works project manager Peter Gibson said the site was determined following a thorough investigation that prioritised five erosion sites from an initial list of 13.

“The final project site, spanning five hectares, was selected in consultation with the Burdekin Shire Rivers Improvement Trust,” Mr Gibson said.

“Neilly Group undertook the design using advanced modelling techniques, and has also been appointed to undertake the construction.

“Preventing this amount of fine sediment reaching the reef will improve water quality and reduce turbidity — supporting corals and seagrasses to get the sunlight they need to thrive,” he said.

According to NQ Dry Tropics, the Burdekin catchment is the largest contributor of fine sediment to the Great Barrier Reef.

Much of this is caused by erosion from grazing lands and stream banks entering the Burdekin River, where it is either deposited in the channel, on the floodplain, or transported out to sea. Fine sediment is a problem because it makes water turbid, reducing the amount of light that seagrasses and corals need to grow and thrive.

The Streambank Remediation in the Burdekin Catchments project was funded by the Australian Government’s Reef Trust.