Waterways - Mannus Lake Blue-green Algae Monitoring

 Alert Level

14 December 2018, 5.28pm  - 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. 

Water Monitoring 

Snowy Valleys Council is actively monitoring 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:

  • 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.

Current alert levels are provided below:   


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

Additional information from WaterNSW can be accessed at:

Domestic Water Assistance 

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 over the 2018/19 Summer Season.

To apply for water assistance please click here to download the application form(PDF, 209KB)