Blue-green algae alert at dam and Bray Park Weir

07 October 2020

Dam alert downgraded but caution sought

Tweed Shire Council has downgraded its blue-green algae alert at Clarrie Hall Dam from amber to green. Meanwhile, blue-green algae has been detected at Bray Park Weir, also at a green alert level.

A green alert means that blue-green algae is present but in low densities. At these levels, the blue-green algae typically do not pose a threat to recreational activities, stock or domestic use.

“Testing at our NATA-accredited Tweed Water Laboratory Centre, renowned for its expertise in blue-green algae, has found no evidence of the blue-green algae species capable of producing toxin in the weir pool – which is where the Tweed’s reticulated water supply is drawn,” Manager Water and Wastewater Operations Brie Jowett said.

“But even if this species were found, our water treatment processes remove blue-green algae from the water when blooms occur so our water would still be perfectly safe to drink.”

Blue-green algae occur naturally and can reproduce quickly in still or slow-flowing water when it is warm and sunny and there are sufficient levels of nutrients in the water body.

Testing during the amber alert issued for Clarrie Hall Dam on Friday 25 September 2020 showed that the algae species did have the gene capable of producing toxin, but there was no evidence that any toxin had been produced.

“Knowing that the gene capable of producing toxin had been present, together with the continuing favourable conditions for blooms, Council is taking a precautionary approach and continuing to restrict recreational activities at the dam,” Ms Jowett said.

“Warning signs at the dam wall and Crams Farm will stay in place until we are confident there is no risk to recreational kayakers or fishers coming into contact with the water,” she said.

Council will continue to test the water at the dam, in the river and at Bray Park Weir pool.

Water affected by blue-green algae appears to have a green paint-like scum on the water, near the edges, or greenish clumps throughout the water.

Anyone who thinks they may have been in contact with blue-green algal water is advised to seek medical advice if symptoms appear.

For the latest, visit Council’s website www.tweed.nsw.gov.au/WaterAndWastewater