Strathmore gully | Landholders Driving Change

Initial site assessment.

Work due to begin on fourth large-scale gully

Work is expected to start soon on LDC’s fourth large-scale gully remediation site.

It’s on Strathmore Station near the Bowen River rodeo grounds, 1.3km from the Bowen River bridge.

Site investigations and design plans will progress during the next couple of months with construction expected to start in September. 

Discussions are also being held with landholders about the management of the site and how to best return it into usable pastoral land. 

The location was selected by the Griffith University project team as a high-value site to reduce fine sediments entering to the Great Barrier Reef lagoon.

Remediation will focus on a number of the highly-active gullies on a small right-hand tributary to Red Hill Creek, which joins Red Hill Creek about 2km upstream from the confluence of the creek and Bowen River. 

Initial investigations showed the gullies had eroded to bedrock at their base, but there was still a significant amount of sediment eroding horizontally. 

Remediation has previously been attempted in the area with some improvements to the sediment yield. 

With support from the LDC project, these efforts can be improved by implementing effective solutions that have been tried and tested on other LDC remediation sites.

Local designers and contractors will be involved as they have in other LDC landscape remediation projects.

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Figure 1. Total fine sediment reduction by project type and erosion source. Inset shows the proportion of the total project area for each project type.

These estimates have been calculated using two methods: 

1) The pollutant reduction component of the Alluvium/Great Barrier Reef Foundation (GBRF) investment tool for hillslope and streambank erosion management projects; 

2) The Reef Trust Gully Toolbox method for gully erosion management projects. The LDC Water Quality Report 2020 (Waterhouse et al., 2020) highlights that a number of assumptions underlay these calculations, therefore these figures should be treated as the best available estimate of sediment reductions to date.

Preventing sediment from reaching the Great Barrier Reef

Each wet season sediment is washed into local waterways and out to the Great Barrier Reef (GBR). 

Most sediment is very fine, and can stay suspended for a long time and can travel great distances. Valuable topsoil is lost from production, and increased concentrations on the reef can be harmful to seagrasses and corals. 

Landholders in the BBB have completed 69 on-ground water quality practice changes, and it is estimated that these have contributed a fine sediment reduction of 6,154 tonnes per year from reaching the GBR. 

Of this, approximately half of the sediment savings are attributable to grazing land management changes on hillslopes and streambanks, and the other half as a result of gully remediation treatments across a broad range of scales, as shown in the graphs above. 

The table below also highlights the relatively small area of intervention in the gully management projects compared to the large sediment savings that these can achieve - 60 per cent of the sediment savings over only 4 per cent of the project area.

Table 1. Estimated sediment reductions (tonnes) from projects completed in the LDC Project to date.

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*GLMWW = Grazing Land Management Wire and Water

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*The Exploring New Incentives activity area has provided an opportunity for graziers to adopt improved land management practices through a range of activities. For some of these properties, it was the first time they signed contracts for on-ground works.

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The LDC project monitors four gully sites (represented in this table) with gold standard equipment and analysis, carried out by CSIRO.

Results have been compiled in a preliminary report from Bartley et al (2020), with the final report expected to be released by the end of 2020. The preliminary report shows all four sites have indicators of improvements, notably the Strathbogie and Mt Wickham sites.

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Reef regulations - grazing, standard conditions

  1. For land in good or fair condition (more than 50 per cent ground cover at 30 September), continue using measures to maintain land condition.
  2. For land in poor condition (less than 50 per cent ground cover at 30 September), steps must be taken to improve land condition.
  3. For land in degraded condition (less than 20 per cent ground cover at 30 September), steps must be taken to improve land condition OR prevent areas from further degrading or expanding.
  4. Keep records of measures taken and also of agricultural chemicals, fertiliser and mill mud or mill ash applied to land.
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