We are planning to remediate four significant streambank erosion sites along the Tully River this dry season to help reduce sediment runoff (silt and clay) and protect agricultural land.

The works are part of a six-year project to fix eroding streambanks, gullies and hillslopes across the Wet Tropics. Sites have been identified and prioritised based on risk to water quality flowing to the Great Barrier Reef.

The environmental engineering solutions being used for the Tully sites involve the construction of pile fields and the placement of rock along the streambank.

WHEN WILL WORKS COMMENCE?  

The construction period is planned for 8 July to late October.

WHAT IS BEING DONE? 

Four sites are being targeted along the Tully River in 2025. Other sites have works scheduled in over the next four years. Rock beaching is planned for two of the sites. Pile fields will be constructed at the other two sites.

The remediation works are designed to protect farmland, reduce sediment flowing to the reef and provide natural habitat for fish.

WHAT IS ROCK BEACHING?

Rock beaching is a method used to protect riverbanks from erosion. It involves placing layers of angular, quarried rock along the bank in a carefully designed way. The rocks are graded and laid to a specific thickness so that they lock together, forming a strong, stable barrier. This interlocking structure absorbs the energy of flowing water, helping to prevent further erosion and protect the surrounding landscape. Rock beaching is a reliable, long-lasting riverbank stabilisation solution for high-risk areas.

WHAT IS A PILE FIELD? 

A timber pile field is an erosion control structure used to protect vulnerable stream banks. It is multiple rows of closely spaced timber piles, driven into the streambed and banks. These piles slow the flow of water, reducing erosion and allowing sediment to settle. Over time, this trapped sediment helps to rebuild the stream bank and creates a stable environment for native vegetation to grow. Eventually, the vegetation takes over the role of protecting the bank and the timber piles naturally degrade. Timber pile fields are a sustainable, nature-based solution to restore and protect waterways.

ARE PILE FIELDS A RISK TO BOATING? 

These pile fields will be along the bank, not in the river, so they will not pose a risk to boat traffic.

A new $31 million project will reduce sediment runoff to the Great Barrier Reef from the Wet Tropics region. The six-year project is targeting eroding streambanks, gullies and hillslopes, and will prioritise and design solutions for erosion sites identified as the highest risk for water quality.

The ‘Reef 2035 Sediment Reduction Project’ is being funded by the Australian Government’s Reef Trust and managed by Far North Queensland natural resource management organisation Terrain NRM.

Terrain CEO Stewart Christie said the project is the start of the next phase of investment for reef water quality programs.

“Over the last 15 years there has been a strong focus on reducing land-based runoff, and landholders across the region have been working hard to change land management practices,’’ he said. “As a result, there has been good progress towards Australia’s Reef Water Quality 2050 targets. But there is still more work to be done.”

Mr Christie said the new program would begin with streambank and gully survey work to identify and prioritise erosion hotspots across the region, with a focus on improving the land and reducing fine sediment loads in our waterways and on the Great Barrier Reef. This would be followed by the design of engineered solutions and then the on-ground works.

“Keeping topsoil on the land is vitally important for production. Likewise, good water quality is vitally important for healthy waterways and for the Reef – it affects everything from microscopic plants to corals and barramundi,’’ he said.

“This project will focus on runoff that leads to fine sediment in our waterways, because it’s the fine sediment that reduces the amount of sunlight penetrating the water and that’s a problem for things like seagrass and corals which rely on sunlight to generate energy. Then there’s a trickle-down effect to all sea life relying on the corals and seagrass for food and shelter.”