High levels of blue-green algae produce toxins that can affect the health of humans, animals, birds and livestock as well as harm the environment.

Blooms are common in the warmer months in Victorian rivers and lakes and can be triggered by a combination of:

  • nutrients in the water
  • low water inflows and storage levels
  • warmer weather conditions

When we become aware of an algae bloom in one of our waterways, we may issue a warning. It's important that you respect any changes to recreational activities at lakes, reservoirs, rivers and wetlands where warnings are issued.

 

Algal Alert Level Definitions

GWMWater uses the following 3-step scale to alert customers of Blue Green Algae levels:

 Green

0-0.6 mm3/L

Blue Green Algae is present in the water at low concentrations. Water is potable (drinkable) provided it is supplied through a Water Treatment Plant and is considered safe for recreational, stock and domestic use.

 
 Amber

0.6—4.0 mm3/L

Blue Green Algae is present in the water at concentrations that may pose human health risks. Water is non-potable (not drinkable), unless it is treated through a Water Treatment Plant which is designed to treat Algae, but remains suitable for recreational use. Rural pipeline customers are advised to seek veterinary advice prior to watering stock during an amber alert. Regular sampling is undertaken at this alert level.

 
 Red

>4.0 mm3/L

Blue Green Algae is present at high concentrations (bloom conditions) that may pose human health risks. Water is non-potable (not drinkable), unless treated by a Water Treatment Plant which is designed to treat Algae, and is not suitable for domestic or recreational use. Rural pipeline customers are advised to seek veterinary advice prior to watering stock during a red alert.

 

For warnings for the Murray River, refer to algal information issued by the NSW Department of Primary Industries.

 

 

How to recognise a blue-green algae bloom

Blue–green algal blooms often cause a green/red/brown discolouration of the water. Sometimes scum forms on the water surface and an earthy or musty smell may be present.

Although algae blooms can sometimes be seen, water samples need to analysed to know for sure.

If you suspect a blue-green algae bloom, contact us immediately on 1800 188 586.

 

Blue-Green Algae Regional Coordination Plan

GWMWater is the Regional Coordinator for a major blue-green algae outbreak for a number lakes, reservoirs, rivers and wetlands within our region.

More about our Blue-Green Algae Regional Coordination Plan.

 

Further information on Blue Green Algae

Department of Environment, Land, Water and Planning (DELWP) https://www.water.vic.gov.au/waterways-and-catchments/rivers-estuaries-and-waterways/blue-green-algae

Australian Drinking Water Guidelines https://nhmrc.gov.au/about-us/publications/australian-drinking-water-guidelines

Agriculture Victoria http://agriculture.vic.gov.au/agriculture/farm-management/blue-green-algae-issues/blue-green-algae-questions-and-answers 

There are currently no blue-green algae warnings