Blue-Green Algae High Alert for Mannus Lake & Mannus Creek

Published on 14 December 2018

WaterNSW have issued a red level warning (high alert) for Mannus Lake and downstream Mannus Creek. This algal warning is expected to continue to move further downstream with water flow.

Snowy Valleys Council’s Acting Director Assets and Infrastructure Heinz Kausche said analytical results have confirmed high levels in the lake of a species of blue-green algae identified as potentially toxic.

“Council has erected warning signs at key recreational areas around the lake and creek which will remain in place on advice from WaterNSW, while high levels of the blue-green algae are present”, Mr Kausche said.

WaterNSW advises people not to enter the water, not to drink untreated water or bathe in water drawn from the lake or creek while this red alert level warning is in place.

“WaterNSW have identified the species of blue-green algae as potentially toxic and may cause gastroenteritis in humans if consumed and skin and eye irritations after contact. They have advised that boiling the water does not remove algal toxins”, Mr Kausche said.

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

Mr Kausche said low levels of blue-green algae are generally present in freshwater at all times.

“When a series of favourable environmental factors occur, including warm water temperatures, sunny days and an abundance of nutrients, a blue-green algae bloom can result,” Mr Kausche went onto explain.

Mannus Lake experienced it’s very first recorded severe algal bloom in late 2017, resulting in the short term loss of domestic water supply for a number of properties.

“It is not possible to predict how long the algae will remain at high levels. Council will continue to take water samples at intervals until two consecutive samples are below the required limit, where WaterNSW will lift the alert”, Mr Kausch said.

Livestock owners are reminded to continue to check stock water supplies for blue-green algae and to remove stock from these waters where surface scum is visible or blue-green algae are suspected.

Although not ordinarily responsible for the water supply to properties, Council recently resolved to provide affected households with up to 13,000 litres of domestic water per fortnight during an algal bloom outbreak in the lake and creek.

“At its meeting held on the 11 December, Council has allocated to respond quickly to applications for assistance from impacted households, if it is seen as necessary to do so,” Mr Kausche said.

“Council Officers will maintain direct communication with affected landholders keeping them up to date with the latest news via email, and phone calls where required.

“People who believe they may have been affected by blue-green algae are advised to seek medical advice”.

To apply for water assistance please download the application from Council’s website: svc.nsw.gov.au/algae-assistance

Information updates about blue-green algae blooms and red level warning areas can be obtained from the Regional Algal Coordinating Committee free-call Algal Information Hotline on 1800 999 457 or visit – www.water.nsw.gov.au