Toxic Algae Alerts

The alert level is based on an assessment of the percentage of river bed that a cyanobacteria mat covers at each site. Other factors may indicate an increased risk of toxic cyanobacteria, such as the contribution of cyanobacteria from further upstream or sections of river where floating mats may accumulate. 

Alert level Health Risk
exposure to cyanobacteria toxins
Extent of cyanobacteria cover Action
Surveillance Low Zero to 20% Most parts of rivers will not have cyanobacteria. Take usual care and be aware of cyanobacteria and risks
Alert Low to moderate 20-50% Take extra care to avoid contact with cyanobacteria when entering rivers. Check weekly council monitoring and alert updates
Action High 50%+ Avoid entering rivers that council has identified. Check weekly council monitoring and alert updates for any change in status

Information about what to do during the different alert levels can be found in the Frequently Asked Questions.