site. Of course, there are other likely influences, particularly rainfall; 2022( first year of monitoring) was a wetter year than 2023. This project was not a scientific research project; isolating the effect of grazing of the Sodosol sites from other factors is not possible. However, there does seem to be broad, not-unexpected patterns in the relationship between the level of stability / success of remediation and the land manager’ s‘ Focus on improving land condition’. This is displayed in Figures 17 and 18.
Catchment remediation is more likely to achieve a high stability rating despite the grazing land management, particularly on flat terrain( Figure 17). In contrast, remediation works in gullies are likely to do better under management that focuses on improving land condition, but this does not guarantee success e. g. achieving stability within five years( Figures 18 and 15). This concurs with the advice of many erosion management practitioners— exercise caution when planning to remediate gullies in erodible soils( e. g. Sodosols), and vegetation( ground cover, biomass, plant diversity) is essential for long-term stability( Carey et al., 2015, Ch. 13 p. 21; Wilkinson et al., 2022; Landloch Pty Ltd, 2024, p. 2). For gully sites that are fenced out, a forage budget will likely reveal that grazing the recommended 10 per cent of the standing dry matter is unlikely to have a significant production benefit.
What changes to planning, design and implementation are recommended to improve small-scale gully remediation?
Plan for tropical deluges, limited infiltration and high runoff
The BBB is in the topics and, therefore, most of the rain falls in summer with a lot being delivered during high intensity events( Table 1). Consequently, most of the rainfall is likely to become overland flow rather than infiltrate into the soil. Furthermore, Hawdon et al.( 2025, p. 2) found that, while sediment was reduced through effective remediation works, runoff was not significantly reduced at the four sites which included Sites 1, 2 and 24. This challenges a commonly held assumption that remediation works, together with the establishment of deep resilient vegetation, will reduce the quantity of runoff that flows into channels, gullies and creeks.
Consequently, structures need to be designed to an appropriate intensity of rainfall event( with little or no discounting for assumed improved infiltration) and most structures should aim to spread flow rather than concentrate it. Furthermore, it is the ground cover( vegetation) that is driving the sediment reduction so, for long-term success, structures need to be supported with revegetation and this needs to be carefully managed, including protection from grazing pressure( Hawdon et al., 2025, p. 37).
Adhere to the plan
Of the 19 sites, nine are deemed to have underperformed; they either required maintenance or failed to stabilise. For two thirds of these sites( 6 / 9) the deficiencies can be attributed to not following best practice when implementing the plan. Inadequate site supervision was common and there were relatively small, but significant departures from plans. There were no documented post-construction surveys. This is an identified area needing improvement for both small and large-scale sites( Landloch Pty Ltd, 2024, p. 3) and reflects the general lack of suitably qualified people in the sector.
Understand the soil and plan accordingly
Catchment works are low risk and can be an important first step in managing gully erosion. However, as for the gullies themselves, the soil in the catchment needs to be well understood to plan appropriate catchment works. Important soil characteristics to investigate are infiltration rate, stability( stable, slaking or dispersive), depth of topsoil and the fertility( structural and chemical) of the subsoil. Diversion banks, stick lines and shallow ripping to slow runoff need to be justified and cost-effective, and should only be considered after changes in grazing land management have been explored. Sometimes mechanical intervention is not warranted; land condition can be improved sufficiently through exclusion or resting in the wet season. If ripping is implemented, the depth of the effective soil for the desired plants needs to be known; there is little benefit in ripping into a subsoil that the roots of pasture plants cannot penetrate or survive in. This is usually the case for the Sodosols of Box country; the most common soil type amongst the small-scale gullies monitored in this project.
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