Bus tour of some of the LDC gully remediation sites wraps up project
The Landholders Driving Change project (2017–2022) tackled erosion in the Bowen, Broken, Bogie (BBB) catchment by remediating 24 gullies, treating more than 11,000m of erosion, and preventing an estimated 5,500tonnes of sediment from reaching the Great Barrier Reef each year.
Fine sediment is a major threat to the Great Barrier Reef, and gully erosion is now recognised as a key source of that sediment.
Around 40–50 per cent of the fine sediment reaching the Reef comes from gullies, although this varies between regions.
To help protect the Reef, the Australian and Queensland Governments set water quality targets through the Reef 2050 Water Quality Improvement Plan.
Most of the fine sediment in areas like the BBB, comes from sub-surface sources like gully and channel erosion, with gullies being the main focus for action.
Until recently, only smaller gullies were treated using low-cost, low-tech solutions. There was little understanding of how to fix larger, more active gullies, or by how much sediment could actually be reduced.
The LDC project combined landholder knowledge with scientific expertise, using tools like LIDAR and soil sampling to assess and design site-specific interventions. Techniques ranged from large engineered earthworks to smaller landholder-led fixes.
During three years, the Gully Maintenance and Monitoring project monitored 24 gully sites annually using tools like the Land Condition Assessment Tool (LCAT). This project showed maintenance was essential, especially after large works, and working with nature and time could offer more cost-effective outcomes.
Local graziers and other stakeholders attended a field day in April to share insights on gully remediation—what worked, what didn’t, the challenges faced, and how to improve future efforts.
A key success of the project was building trust and collaboration among landholders, scientists, engineers, and the government, shifting the culture from top-down instruction to shared learning and respect.
This inclusive, adaptive approach is now informing future gully remediation and monitoring efforts.
To learn more about the work carried out at specific sites—including monitoring results, key lessons, and insights from landholders—explore these case studies.
Much of the work we’re discussing today is an expression of soil hydrology playing out across the landscape — and our efforts to engineer change to reduce sediment loss, particularly the fine sediment that eventually reaches the Great Barrier Reef.
The LDC program was driven by landholder input from the outset, with priorities largely shaped by those on the ground. One of the major early challenges was how to effectively rehabilitate large and severely eroded gullies. At that time, there was limited practical knowledge, so it became a process of trial, learning, and adaptation.
Much of the work you’ll hear about today has helped extend our collective understanding.
— Christian Roth
Former research scientist with a 40-year background in soil erosion and soil hydrology, Landholders Driving Change Project Panel member.
We can’t take a “set and forget” approach—especially not at large-scale sites. Maintenance is essential. We need to stop hoping it won’t be necessary. The amount required depends on the initial quality of work, the methods used, and uncontrollable factors like rain or drought.
Large-scale works involve major soil disturbance and loss of natural stability, so maintenance is critical to prevent further degradation. Even on smaller sites, if you’re doing earthworks—like building banks—you must plan for follow-up maintenance, with timely access to machinery to avoid bigger problems later.
For cost-effectiveness, we should work with nature where possible, even if that means a slower, staged approach. While large jobs might need heavy machinery, many situations may benefit from letting natural processes assist.
We’re still learning. Monitoring helps us apply lessons acropss similar sites, so it’s vital to record and share what we learn — just like we did today.
— Bernie Claussen
NQ Dry Tropics Soil Conservation Officer
It’s great to see real progress in the gullies—that’s why we’re there: water quality. We’ve learnt that gully remediation is complex—every site, farm, and farmer is different. There’s no one-size-fits-all, but now we’ve got data, proven techniques, and a broader, more confident toolkit to work with.
— Garlone Moulin
Mt Pleasant grazier, Landholders Driving Change Project Panel member
When we bought our place, there was so much to do that it was hard to know where to start. Working with NQ Dry Tropics made a huge difference. We began by fixing one small gully, now we’re up to our sixth. I’ve seen the benefits firsthand, and I’m 100 per cent on board. I’m keeping the soil where it belongs, on the property, not washing into the creek. We’ve brought the pasture back, and we’re managing it to keep improving. I’ve learnt so much along the way.y not at large-scale sites. Maintenance is essential. We need to stop hoping it won’t be necessary. The amount required depends on the initial quality of work, the methods used, and uncontrollable factors like rain or drought.
— Barry Collett
Grazier, Collett Excavation and Earthmoving
Ecological engineering firms Alluvium and Verterra developed the remediation technical design and managed the on-ground works at the Mt Wickham gully site.
We’re standing on one of the main rock types used in gully restoration, and transporting and placing this material is a major cost driver—sometimes the logistics cost more than the rock itself. While we used to use filter fabric, it’s mostly phased out now in dispersive soils because it can create problematic layers. Instead, we use a filter layer of mixed-sized gravel, engineered using software to suit the gully profile.
This structure is essentially a large engineered rock check dam, built at intervals to slow water and reduce erosion. It’s constructed with carefully graded rock—this one likely has a D50 of 300mm (largest rocks ~600mm, tapering down to <100mm)—so the rocks lock together and resist being moved by water. The design includes keying the structure into the gully sides and base, and sometimes a strip of geotextile is placed at the head to stop fine sediments from washing through and to promote settling.
Vegetation is re-established over and around the structure, with soil amendments added based on testing. The downstream end often includes a flat rock apron to manage the hydraulic jump—a turbulent wave created when fast water suddenly slows. These structures are designed to handle high flows up to the point of drown-out, at which point flow becomes smooth and erosion risk drops.
— Jason Carter
Principal Project Manager, Alluvium
The erosion in this paddock was severe, far beyond what I could manage on my own. When NQ Dry Tropics approached me about fixing the gully erosion, I saw it as a great opportunity. They brought technical expertise and funding, which significantly eased the financial and logistical burden. Engineers designed and implemented tailored solutions that I wouldn’t have been able to achieve alone. It’s a significant investment, and at the end of the day, all stakeholders need to understand how much it costs to restore large gullies.
— Warren Woodhouse
Grazier, Mt Wickham Station
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