Mannus Lake Blue-green Algae Monitoring

Snowy Valleys Council actively monitors Mannus Lake for blue-green algae. Alert levels are published in consultation with WaterNSW.

Blue-green algae are a common and naturally occurring component of most recreational water environments. They are a public health concern because some types produce toxins that can have a harmful effect on recreational water users.

Monitoring of recreational water is essential to identify the risk of blooms, and take into account the actual or potential accumulation of toxic algae.

The Guidelines for Managing Risks in Recreational Water provides a three-level monitoring system for alerts:

  • Blank cell - no sampling undertaken;
  • Nil - indicates levels of blue green algae are below reporting limits
  • Surveillance mode (green level) – routine sampling to measure blue-green algae levels
  • Alert mode (amber level) – Investigations into the cause of elevated levels and increase sampling to enable risks to recreational users to be more accurately assessed.
  • Action mode (red level) – Local authority and health authorities to warn the public that the water body is considered to be unsuitable for primary contact recreation.

 Click here to view the current water sampling alert results (PDF, 129KB)

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. Blue-green algae usually appear as green paint-like scums on the water, near the edges, or as greenish clumps throughout the water. It makes the water appear dirty, green or discoloured and generally has a strong musty or earthy odour.

For more information, please contact Council on 1300 ASK SVC (1300 275 782) or email [email protected]

Additional information from WaterNSW can be accessed at:

Domestic Water Assistance 

Council 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

To apply for water assistance please click here to download the application form(PDF, 181KB)