Algae alert downgraded at dam, added for weir
THE amber alert for the blue-green algae found at the Clarrie Hall Dam has been downgraded to green while the toxic bacteria has also been found at the Bray Park Weir.
A green alert, now also applied to the Bray Park Weir, means blue-green algae is present in low densities.
The Tweed Shire Council confirmed at these levels, the blue-green algae typically do not pose a threat to recreational activities, stock or domestic use.
Water and Wastewater Operations manager Brie Jowett said testing at the NATA-accredited Tweed Water Laboratory Centre has found no evidence of the blue-green algae species capable of producing toxin in the weir pool.
The weir pool is where the Tweed's reticulated water supply is drawn.
"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," Ms Jowlett said.
Blue-green algae occurs 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 September 25 showed 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, the 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."
The 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.