Blue-green algae amber alert at Clarrie Hall Dam

25 September 2020

Tweed Shire reticulated water not affected

Treated water from the Tweed mains supply is not affected by an amber alert for blue-green algae being issued for Clarrie Hall Dam.

Currently the Tweed’s reticulated water supply is being drawn entirely from the Tweed River without any releases from Clarrie Hall Dam, isolating the amber alert to the dam water.

“Customers can be assured that the drinking water from the town supply is perfectly safe for human consumption because none of our water is currently coming from the dam and the dam is not spilling water to the river,” Manager Water and Wastewater Operations Brie Jowett said.

“Our treatment processes are designed to make sure we are able to treat such events when they do naturally occur in the river.”

Blue-green algae occur naturally and can reproduce quickly in favourable environmental conditions, such as where there is still or slow-flowing water, abundant sunlight and warm weather as well as sufficient levels of nutrients.

Council’s testing has confirmed that the blue-green algae species within the dam has the toxin gene (mcyE) responsible for toxin production. That is, it has the ability to produce toxins but at this stage there is no evidence that it has produced toxins.

As a precaution, Council has placed signs at the dam wall and Crams Farm to warn the public. These will stay in place while the high levels of blue-green algae remain.

“All recreational users of the dam and visitors to Crams Farm and the dam wall are advised to stay away from the water and definitely do not drink it,” Ms Jowett said.

The amber alert for Clarrie Hall Dam also means the water in the dam and its upstream and downstream tributaries could potentially be unsafe for livestock.

Council has ramped up its water testing regime to monitor the situation at the dam and be prepared for any future blue-green algae outbreak in the river and weir pools.

“Our water laboratory has scientists who lead the field in identifying and testing blue-green algae, so we can assure our customers that they are in safe hands when it comes to our drinking water,” she said.

Affected water 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.

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Caption: Treated water from the Tweed mains supply is not affected by an amber alert for blue-green algae being issued for Clarrie Hall Dam.