Monitoring and maintenance on BBB gullies

The Landholders Driving Change (LDC) project successfully remediated 24 gullies — 19 small-scale and five large-scale — across the Bowen-Bogie-Broken (BBB) catchment area between 2017 and 2022.

These efforts collectively addressed more than 11,000 linear metres of gully erosion originating from 54 gully heads, resulting in an estimated annual reduction of 5,536 tonnes of fine sediment reaching the Great Barrier Reef each year.

Since 2022, annual monitoring has been conducted to assess the effectiveness of these remediation works and to identify maintenance needs.

Monitoring showed eight sites — comprising five small-scale and three large-scale gullies — required minor maintenance, including repairs to diversion bank walls, rock chutes, check dams, and the management of rill erosion and invasive weeds.

The project is scheduled to conclude in mid-2025, at which point a comprehensive technical report will be produced.

This report will detail the monitoring framework, maintenance prioritisation processes, site characteristics, and the outcomes and lessons learnt from each site. 

Additionally, it will provide insights into the timeframes and costs associated with maintaining gully stability in the long term, thereby providing confidence in investment and sediment reduction strategies.

Graziers in the BBB catchment are actively collaborating with NQ Dry Tropics as part of the Burdekin Major Integrated Project – Gully Maintenance and Monitoring project, to develop a shared understanding of gully erosion, its causes, how to fix it, and the ongoing maintenance required to ensure long-term success.

SMALL-SCALE GULLIES

Many graziers, including Scottville grazier Barry Collett, have been hands-on in addressing small-scale erosion issues, taking the initiative to implement sustainable grazing practices.

These practices aim to reduce grazing pressure, allowing vegetation to re-establish on previously eroded areas.

Graziers have played a vital role in observing the outcomes of rehabilitation efforts over consecutive years.

Their firsthand experiences provide valuable insights into what strategies have worked and what needs improvement, as they work toward finding maintenance solutions that are both effective and sustainable.

By partnering with NQ Dry Tropics, graziers like Barry Collett have shared their experiences, particularly the challenges of dealing with sodic soils and identifying long-term solutions to prevent sediment runoff, thereby protecting the land and local waterways.

LARGE-SCALE GULLIES

Burdekin grazier Paul Fry has witnessed firsthand the complexities of large-scale gully remediation at Strathmore Station, where significant efforts were made to address soil erosion and prevent the loss of fine sediment into nearby waterways.

The Strathmore Station rehabilitation project focused on ground intervention to reduce erosion, establish vegetation, and reduce the export of sediment.

Unlike typical gully rehabilitation projects, which target more defined trunk gullies, the Strathmore site featured a vast amphitheatre of erosion, with wide gully floors and substantial topsoil loss across large areas. 

The remediation work primarily involved revegetating the catchments above the gullies to prevent further expansion of the eroded areas.

Paul said soil had been washing away from the catchment for an extended period and fixing the area was essential. However, he also noted the significant challenges involved in addressing large-scale gullies.

“It’s a huge undertaking to fix large gullies,” Paul said. “It costs millions of dollars… bulldozers, machinery, operators—it all adds up.”

Paul highlighted the importance of cost-effectiveness and the necessity of long-term maintenance, saying that without ongoing maintenance, the investment in gully remediation would be wasted.

He also emphasised the need for a skilled, local workforce to take part in the process, ensuring local people understood different rehabilitation techniques and took ownership of the projects.

He recognised that while heavy machinery like bulldozers could be beneficial, a lighter touch, such as using hay bales, constructing bund walls, and installing rock chutes, had proven effective in certain sections of the Strathmore gullies. This approach would need to be monitored to see how well it holds up.

Ultimately, Paul stressed that managing the land effectively — by being mindful of stock numbers, spelling paddocks, implementing weed management, and ensuring the correct placement of infrastructure like fencing and water points — is key to long-term success in landscape repair.

Grit editions

Also in this edition