TropWATER Research Scientist Zoe Bainbridge talks about the results of the 2020-2021 Wet season to members of the community monitoring group.

Zshkeen Kerr (left) and Norman Johnson.

TropWATER’s Zoe Bainbridge and NQ Dry Tropics Land Management Support Coordinator Rodger Walker.

Community gets results of water quality monitoring

The LDC Community Water Quality Monitoring Group is learning more about how, when and where sediment moves throughout a range of flow events. The group met in September to review water sampling results from the 2020-2021 wet season at an event held at Urannah Station.

For the past three years, landholders around Bowen and Collinsville have collected water samples during the wet season at nine sites across Burdekin tributaries and major sub-catchments, as part of the LDC project.

The data is supporting the project with information on how best to tackle gully remediation, and keep soil on the land through improved management practices, to enhance water quality.

In September, James Cook University’s TropWATER research scientists Zoe Bainbridge and Steve Lewis briefed members of the project’s Community Water Quality Monitoring Group on the results of their wet season water sampling.

They delivered the results after a less-than-average wet season at an informal gathering hosted by the Urannah Property Association on Urannah Station.

Zoe said the group’s role as water quality monitors meant they had a direct hand in building a more informed picture of sediment carried in the waterways.

The data collected by the monitoring group is used by the Queensland Government’s Paddock to Reef (P2R) program to improve modelling and help inform future investment in the region.

The 2020-2021 Wet Season Update of the LDC Water Quality Sampling results has been published and, along with the results from previous years, is available here.

TropWATER has developed a conceptual map of Burdekin fine sediment sources, transport and export based on current scientific understanding. It’s a handy reference that you can read here. 

Basin contributions to end-of-river sediment loads have been determined using the Burdekin Source Catchments model (Paddock To Reef Program (P2R) program) and TropWATER’s research conducted at catchment scale.

Garry Reed listens as TropWATER Zoe Bainbridge details some of the data gathered by the water monitoring group.

NQ Dry Tropics Land Management Support Coordinator Rodger Walker is flanked by TropWATER’s Zoe Bainbridge (left) and Charmaine Foley (UPA).

 

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.
KEQ #8

KEQ #7
KEQ #6

KEQ #5

KEQ #4

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.

KEQ #3

*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.

KEQ #1

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.

KEQ #2

*GLMWW = Grazing Land Management Wire and Water

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