intensive land reshaping and soil amelioration is deemed not cost-effective. The small-scale gullies in Sodosol soils proved difficult to remediate with bare areas slow to revegetate. In contrast, gullies in Vertosol soil healed more readily. The catchments of Sodosol gullies may stabilise within three years whilst those in the Downs country Vertosol soils may take only two years.
The costs of maintenance for the large-scale sites was relatively low and within a generally acceptable proportion of initial costs( 1.7-9.9 per cent). In contrast, the cost of maintenance works at small-scale sites was high, often more than half the cost of the initial works.
Recommendations from this project include:
• Sufficient time is spent in the early stages of planning to understand the erosion processes occurring at a site to ensure the efficacy of remediation works.
• Remediation plans are informed by a sitespecific risk assessment / s that provides logic to the approach taken, suggests the duration of monitoring and outlines the likely issues to monitor.
• Suitably qualified people are available to plan, supervise implementation and oversee the monitoring and maintenance of engineered structures and revegetation( e. g. five-10 years).
• Monitoring, maintenance and grazing schedules are worked out collaboratively, involve grazing specialists and are documented.
• The requirements of the landholder with regard to protecting the revegetation, monitoring and maintenance responsibilities are clearly understood, and are formally agreed to by all parties.
• Low impact remediation methods are considered for improved cost-effectiveness or when the risk assessment indicates that it is pertinent to do so.
• The revegetation approach could be improved by planting native pasture species and trait-specific plants, using biological ameliorants, irrigating and mulching.
• Rock chutes installed in gullies with dispersive soils are likely to require ongoing maintenance even when they are designed and installed following best practices.
As a consequence the planning stage is likely to take longer and require more collaboration, but is likely to achieve better remediation outcomes and greater cost-effectiveness.
2 GULLY MAINTENANCE AND MONITORING TECHNICAL REPORT