EROSION CONTROL
Weetalaba landscape rehydration: intense rainstorm leads to maintenance
LANDSCAPE REMEDIATION
EROSION CONTROL
Erosion control works at Havilah Station were delivered in two stages during early 2022 and 2023. The works involved reshaping eroded areas, stabilising steep and unstable banks, and installing rock structures to help slow water flow and prevent further damage.
A review by an independent expert in late 2023 confirmed the approach was well-suited to the site’ s challenging soils. However, it also highlighted that recovery would be a long-term process, requiring continued monitoring and maintenance to ensure lasting results.
In mid-2024, NQ Dry Tropics contracted Civil IQ to address areas
where water was causing erosion, including water building up behind raised rock structures, breaking out of its path, and carving into the soil. In some places, cracks and tunnels had formed.
Maintenance included reshaping and stabilising the damaged areas, improving drainage to guide water safely through the site, and reinforcing key points with rock to prevent further washouts. These follow-up works were aimed at protecting the earlier investment and keeping the landscape recovery moving in the right direction.
The Havilah gully site was selected as a priority project based on the work completed by the Griffith University project team as part of the Landholders Driving Change project to characterise and prioritise gully remediation across the BBB catchment. The works consisted of two main gully systems covering 110ha. The majority of the site is on Havilah Station, with a portion to the east on Gattonvale Station. The partnership between the two properties meant the effort on one property to halt the gully expansion, would benefit both.
Weetalaba landscape rehydration: intense rainstorm leads to maintenance
A landscape rehydration project on Weetalaba faced a setback shortly after its completion due to an intense rain event that dropped 170mm of rainfall across several days. This rainstorm, occurring before groundcover had established, led to the need for maintenance of the project’ s structures.
Remediation included constructing grade control rock chutes that complied with the Accepted Development Requirements( ADR) for waterway barriers, as the site sat along a Department of Primary Industries-mapped green waterway.
Works also involved extending the rehydration banks and using rock armouring in key spots, particularly where the banks met the ground, to stop erosion. Small channels and washouts were filled in, and rock check dams were built where water flowed faster and caused damage.
In areas where the ground had sunk, gypsum was added to help stop underground erosion before backfilling with gravel and bigger rocks for strength.
Neilly Group Engineering, and local contractors Colls Earthmoving and Strathdickie Plant Hire undertook this work,( see the three photos at left). Stock has been excluded from the site until revegetation has been established.
Mulloon Consulting, a subsidiary of The Mulloon Institute, designed the project.
The treated erosion site was an incised alluvial fan that had diverted flow directly to Rosella Creek, with active black soil gullies feeding into it and threatening a nearby crop. Naturalmaterial interventions were used to lift and spread water higher in the landscape, aiming to restore an older flow path that ran parallel to the creek for about six kilometres before rejoining it. Rehydration banks were constructed above the gully heads to hold water in the landscape for longer, aiming to slow water movement across the landscape, and to promote infiltration rates instead of running into the gully system. A rock chute was designed to withstand and pass large flows. Slowing water movement reduces erosion and increases pasture yields, generating economic and environmental rewards.
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