INTRODUCTION
The Gully Maintenance and Monitoring project involved the annual inspection and maintenance of 24 remediated gully sites( 19 small-scale and five large-scale) within the Bowen, Broken, Bogie( BBB) catchment during three and a half years( 2022- 2025). A small-scale gully is defined as one with a maximum depth of 3m and is typically on hillslopes. A large-scale gully has a maximum depth greater than 3m and is typically a gully complex, lower in the landscape. The project objectives were to:
1. Monitor the gully stability and carry out critical maintenance that will provide confidence in investment and sediment savings.
2. Engage with landholders to improve their understanding of gully maintenance requirements.
3. Generate longer term learnings around time frames and maintenance costs associated with maintaining gullies in a stable condition.
Project activities included:
• evaluating the monitoring methodology and monitoring plan;
• undertaking and reporting on the annual monitoring of all sites;
• managing critical maintenance of sites as required;
• communicating with landholders regarding site condition and maintenance required; and
• producing this document, a technical report to communicate project findings.
This technical report addresses Objective 3; learnings from the project and includes results of the 24 sites; their progress towards stability, the maintenance required, maintenance costs, and overall cost effectiveness. The discussion will focus on observed patterns in the results associated with characteristics such as soil types and treatments that may help inform future gully remediation work.
BACKGROUND
THE INITIAL TREATMENT PROJECT
The 24 remediated gully sites monitored in this project were treated under the Landholders Driving Change( LDC) project( also known as the Burdekin Major Integrated Project) between 2017 and 2021. These gully remediation sites formed part of the 95 LDC practice changes completed with graziers and summarised in Year 4 Performance Report( NQ Dry Tropics, 2022). The projects saved an estimated 10,600 tonnes of fine sediment reaching the Great Barrier Reef( GBR), half of which was attributed to gully remediation treatments.
THIS MONITORING AND MAINTENANCE PROJECT
Towards the end of the project, partners recognised the need for ongoing monitoring and maintenance work to evaluate the most effective methods( and cost-effective methods) for reducing the sediment( and particulate nutrients) generated and delivered from gullies. It was decided that ongoing monitoring could enable the testing of assumptions on how long treatments would last, the required level and frequency of maintenance, and whether reduction in fine sediment exports continued. This project was funded from underspend in this Landholders Driving Change project.
NQ DRY TROPICS 3