Blue-green algae being monitored

Date published: 28 March 2022

Recent hot and dry conditions created the perfect environment for blue-green algae growth in the Ross River Dam, prompting Townsville City Council to again remind the community about potential impact on the city’s water supply.

As the weather cools down algae numbers are reducing, but Council continues to monitor and manage the blue-green algae in the dam.

Townsville Water and Waste Committee chair Russ Cook said Council continues to learn and adapt to managing the algae.

“The latest testing indicates the level of blue-green algae in the dam has reduced down to around 75,000 cells/ml as the temperatures have cooled off over the past week,” Cr Cook said.

“Despite recent high blue-green algae levels in the dam, raw water continues to be effectively treated at the Douglas Water Treatment Plant, producing drinking water in accordance with the Australian Drinking Water Guidelines.”

Cr Cook said Council officers were working alongside industry experts on the management of blue-green algae in the dam as well as treatment process.

“Council is investigating and applying various solutions, both engineering and environmental, to minimise the impact of algae on our water supply and we will continue to keep the community informed,” he said.

Council has implemented initiatives to address possible blue-green algae blooms in the dam and their impact on the water supply including:

  • implementing catchment management initiatives
  • operating aerators in Ross River Dam to improve dissolved oxygen concentrations
  • installing powdered activated carbon (PAC) dosing at the treatment plant to mitigate taste and odour and toxin risk
  • adding pre-chlorination to all modules at DWTP to improve filtration
  • progressing the construction of two new clarifiers at the Douglas Water Treatment Plant (DWTP).

The construction of the clarifiers will require scheduled shutdowns of certain parts of the DWTP throughout the coming months to allow installation of required valves and pipework and connection to existing infrastructure.

DWTP will remain operational during this time at a reduced capacity which could lead to some temporary limitations on potable water production. Council is urging residents to be conscious of your water use and conserve water where possible.

Council will be monitoring water demand and available production capacity and the community may notice less irrigation of council managed areas as irrigation is reduced where necessary to reduce water demand.