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.”

A Mossman farm has become a demonstration site for Zuni bowls – a solution to gully erosion.

Landholders, engineers, council officers and contractors are visiting the property to learn how to build the structures, where they work best and how they can be used more widely to fight erosion in Tropical North Queensland.

Terrain NRM’s Ruginia Duffy said two Zuni bowls had been built on the farm.

“They are a smaller-scale, cost-effective way for landholders to stop erosion from advancing,” Ms Duffy said. “These bowls follow on from work on an Atherton Tablelands farm last year, where smaller bowls were built and have settled into the landscape.”

Zuni bowls are a lining of rocks built into gully heads where there are abrupt vertical drops. They take their name from the Native American Pueblo people from the Zuni River Valley, who first developed and used the structures.

“These days, work starts with a bobcat and ends with shovels and crowbars,’’ Ms Duffy said. “The structures are carefully designed to prevent water from disturbing the soil any further. They work with the natural landscape – by mimicking the kind of forms found in creeks.”

The latest bowls are part of a larger project repairing flood damage in the Mossman region. Other parts of the project have included more traditional earthworks, rock work and tree-planting to stabilise creekbanks that bore the brunt of floods in the 2018-19 wet season.

The Mossman Integrated Catchment Repair Project is funded by the Queensland Government’s Natural Resources Investment Program.

Rock work and grasses are replacing erosion on a cattle property near Innisfail as part of a $2.3 million project to improve the land and better protect the Great Barrier Reef.

More than 200 tonnes of rock has transformed two sites on the Loudon family’s East Palmerston farm, where changes to cattle and pasture practices are also making a difference.

Stuart Loudon said the property, on Berner and Fishers Creek, had been farmed by the family since the 1960s. “It’s hilly land and when it’s wet, it’s really wet,’’ he said. “We’ve been working on improving the soil, our pastures and the land so it can better handle our cattle and the wet seasons.”

The third-generation grazier has welcomed recent earth and rock work by Terrain NRM at a creek crossing and on an eroded hillside.

“The crossing area had eroded over time because of a natural spring bubbling up out of the ground above the creek in the wet season and the ongoing cattle and farm vehicle traffic,” Terrain’s Vanessa Drysdale said. “It’s the only way to access another section of the farm so we’ve laid a rock bed that’ll get cattle and traffic over soft ground without causing more erosion.”

Ms Drysdale said a gully head was forming beside a sloping pasture on another section of land where cattle once moved between paddocks. “Water was running down the cattle pads in the wet season and being funnelled into the rainforest at a gateway, causing more and more gully erosion,’’ she said. “We’ve created a bowl-shaped area and a bund so that the water spreads out over a much wider area on its way to natural waterways and doesn’t make its way to the gully head anymore.”

Mr Loudon is following up with more fencing, to keep cattle off creek banks and create another paddock for rotational grazing. He said a shift to more natural pasture enhancers was also helping to improve the land.

“We don’t use a lot of fertiliser here anymore – we’re applying a fair bit of fish emulsion and worm juice,’’ he said. “We’ve been doing that for about four years and we’re seeing healthier soil and thicker grass.”