Water quality sampling tracks sediment from the source
Each wet season, a group of committed graziers across the Bowen, Broken and Bogie (BBB) catchment roll up their sleeves and collect water quality samples to help scientists understand how sediment moves through the landscape — and ultimately, how much of it ends up in the Great Barrier Reef lagoon.
Now in its sixth year, the Landholders Driving Change (LDC) Community Water Quality Monitoring Group is helping build a clearer picture of where sediment is coming from. Made up of landholders from nine properties, the group works closely with scientists from TropWATER, James Cook University, who trained them to collect and store water samples to research standards.
During the 2024–2025 wet season, 42 water samples were collected from five sites across the Little Bowen River, Broken River, Bogie River, and Pelican Creek waterways. It takes a lot of coordination and kilometres to get these samples from the paddock to the TropWATER lab in Townsville.
It’s also a great chance for NQ Dry Tropics field officers to connect with graziers and hear what’s happening on the ground.
This collaborative effort, backed by the Great Barrier Reef Foundation for five wet seasons, has resulted in more than 300 water samples being analysed, with more than 190 of those collected directly by local graziers.
The data is already making a difference. Since sampling began in 2018–2019, monitoring has revealed that the Little Bowen River and Rosella Creek sub-catchments contribute about 41 per cent of the total annual average fine sediment load exported by the Bowen River, roughly 739,000 tonnes per year. In contrast, the Broken River contributes just 1 per cent (18,000 tonnes). The highest sediment concentration recorded was 11,000 mg/L (11 g/L) at two Little Bowen River sites, while the lowest was 3 mg/L at the Broken River.
This data is helping improve the accuracy of the Paddock to Reef Integrated Monitoring, Modelling and Reporting Program and is guiding future investment in erosion control.
Erosion is complex, and it comes from hillslopes, streambanks, and gullies. The LDC project is working with graziers to tackle it on all fronts, rehabilitating erosion hotspots, improving land condition through better grazing practices, and encouraging other land managers (like local councils and mining companies) to apply best practices.
Together, this local knowledge and science-based approach is making real progress in reducing sediment runoff and protecting the Reef.
Since its inception in 2018, The LDC Community Water Quality Monitoring Group has been funded by the Queensland Government and through the partnership between the Australian Government’s Reef Trust and the Great Barrier Reef Foundation.
