Insights from our 2023 Waterways Report Card: Water quality
1. Most freshwater sub-basins within the Ross and Black catchments receive ‘good’ or ‘very good’ grades for water quality in this year’s Report Card.
Townsville’s favourite swimming holes — Crystal, Rollingstone, and Alligator Creeks — all receive ‘good’ grades for both water quality and habitat.
2. However, for the fourth Report Card in a row, high levels of nutrients have been found in Townsville’s Bohle River freshwater sub-basin.
Total phosphorus levels remain ‘very poor’ and grades for dissolved inorganic nitrogen have declined since the last report, resulting in an overall ‘poor’ grade for this basin.
According to our Technical Report, activities within the Bohle River basin that may be contributing to the sustained high levels of nutrients include suburban runoff, turf and chicken farming, aquaculture, a golf course, ongoing residential development, the Condon Sewage Treatment Plant, and road infrastructure upgrades.
These potential sources of nutrients, along with ongoing residential development and road infrastructure upgrades, may account for the ‘poor’ scores for Bohle River.
“Every time we water our gardens, and every time it storms, we’re washing pollutants into our river basins. Fertilisers, grass clippings, garden chemicals, dog poo, litter, oils from under the car — it all matters far more than we realise,” Kara says.
Excess nutrients entering our waterways can lead to overgrowth of weeds and algae, resulting in reduced water quality, oxygen depletion, and loss of biodiversity.
Champions of the Bohle — #BackTheBohle
The Bohle basin is very large and takes in Little Bohle and Middle Bohle rivers and Stoney, Saunders, Louisa, and Three Mile creeks – all flowing through the vast Town Common wetlands and ultimately, to the Reef.
“Many partners of the Dry Tropics Partnership for Healthy Waters are already working on a raft of projects to bring the Bohle back into balance,” says our Executive Officer, Kara-Mae Coulter-Atkins. There are many people in the Bohle with their sleeves rolled up for Bohle basin rivers and creekside vegetation, and our Partnership applauds these efforts.”
3. The Report Card also shows that most estuaries get good grades for water quality, but not everywhere
In estuaries of both the Ross and Black Basins, 9 of 13 monitored watercourses received a grade of ‘good’ or ‘very good’ for both nutrient levels and physical-chemical properties.
Camp Oven Creek and Crystal Creek estuaries showed unusually low scores for turbidity, while Althaus Creek continued to show high turbidity. Louisa Creek continues to show low scores for dissolved oxygen and total phosphorus.
‘Turbidity’ measures suspended particles in waterways, such as sediment, silt, organic matter, and microorganisms, and can affect the way sunlight is filtered through water. Insufficient levels of dissolved oxygen in water can lead to stress or even death for many aquatic organisms, including fish, invertebrates, and plants.