the Advanced LCAT collates site data, including erosion, puts some measurement around land condition, it was not designed to assess gully stability, rather land condition is used as a proxy for gully stability.“ The LCAT is designed as a simple, fit-for-purpose science-based method, to determine ABCD grazing land condition; indicate potential hazards related to ecological processes or grazing land management principles; and to provide land condition data for analysis. It is not intended to replace quantitative or more rigorous assessment methods”( Hassett, 2020, p. 4).
The advanced LCAT includes in the assessment the standard components, such as plant diversity, plant density, desirable or undesirable species, soil condition, feral animals and grazing pressure, in addition to indicators of woody vegetation health( understorey and overstorey) and details on the nature of soil erosion at the site. LCAT results are presented in four main ways: A score out of 100, an A, B, C, D rating, environmental risk alerts levels and, important to this study, a list of the key drivers that informed the result( i. e. that reduced the land condition score).
This report concentrates on changes in LCAT scores at sites during the three years of monitoring and notes the key drivers of land condition. This data was used to inform and verify field observations regarding sites’ progress towards no erosion( stability). As the sites were remediated in 2019 and 2020, and this monitoring project began in 2022, the first two or three years following remediation are not tracked. In the absence of LCAT scores before the works were done, control sites were established where possible. In addition, a CSIRO study investigated the effectiveness of remediation activities in gullies from 2017- 2024. Three of the CSIRO sites were also monitored in this project- Sites 1, 2 and 24. In addition to collecting and analysing runoff and suspended sediment, the CSIRO study assessed a number of vegetation measures, including ground cover and biomass to evaluate vegetation recovery. This data helps to inform this report, particularly to understand changes in stability prior to 2022.
The GMT application was developed by the Department of Primary Industries( DPI) following the Gully and Stream Bank Toolbox recommendations for monitoring gullies( Wilkinson et al., 2022, Pp. 71-74). Information captured in this app includes photographs, rating the integrity of structures, ground cover and plant species immediately upslope of structures.
MAINTENANCE METHODS
Between 2022-2024 there were two lots of maintenance organised and funded through the project. Cluster 1 occurred in the dry season of 2023 and Cluster 2 in 2024. Important factors considered in prioritising sites for maintenance work included: the risk to the initial investment if maintenance wasn’ t undertaken and the associated sediment saving, the cost of the initial investment, and the amount of work required. Three of the small-scale sites had some modifications done to the initial design as part of maintenance, to improve the chances of success.
Maintenance works took three different pathways. For the five large-scale sites the engineering contractor who undertook the initial construction project managed the maintenance. The project funded the maintenance of large-scale gullies after maintenance budgets from the initial project were expended. For the 19 small-scale projects, two landholders did earthworks maintenance on their site( in-kind) as necessary after the first rains. For five other sites maintenance was managed by NQ Dry Tropics and funded by the project.
RESULTS
STABILITY OF SITES OVERVIEW
The results of the monitoring and maintenance of the 24 sites is summarised in Table 3. This table retains some columns from Table 2 and maintains the same order of the projects and colour coding to ease cross-referencing. All 24 gully sites were assigned a stability rating in January 2025: stable, mostly stable, partly stable or unstable. All available data collected from the time of construction to January 2025 was used to make this judgement on the stability of the gully erosion. Refer to Appendix 2 for further details on results of the land condition assessments.
NQ DRY TROPICS 13