What are Blue-Green Algae?
Blue-green algae are naturally occurring bacteria often found in Chifley Dam. In small numbers, the blue-green algae are of little concern. However, under some conditions blue-green algae can form large colonies. Blooms can appear quickly and may last hours, days or weeks. They decrease water quality and can pose a risk to human and livestock health through the release of toxins.
Sunlight, warm temperatures, and water high in nutrients create conditions favourable for growth.
What are the risks to human health?
Some species produce toxins that can cause irritation of the skin and eyes, vomiting, diarrhoea, and dizziness.
Exposure to the toxins produced by some blue-green algae species can lead to long-term health issues such as cancer, liver damage and other chronic diseases.
Stay out of the water if you see scums or changes in water colour. If in doubt stay out!
Council's Monitoring Program
Council closely monitors the water quality at Chifley Dam in accordance with accepted guidelines. Council staff collect water samples from a number of locations in the water storage. These are sent to a NATA (National Association of Testing Authorities) accredited laboratory for analysis. As the risk of blue-green algae blooms increases, Council adjusts the frequency and type of monitoring to match the current conditions.
Recreational Alerts
Council closely monitors the water quality at the dam and follows the three recreational alert levels set by WaterNSW:
RED
This alert level represents bloom conditions. The water looks green and the blue-green algae may be seen as clumps or scums (blooms). There may be a strong odour or musty smell. These blooms should be considered toxic to both humans and animals. All contact with the water should be avoided. Water should not be used for drinking, cooking, stock watering, or recreational purposes. At this alert level, Chifley Dam is closed to all water-based recreation. Two subsequent results (from samples each taken at least a week apart) below the red alert level must be received before the alert is adjusted.
AMBER
Blue-green algae may be multiplying. The water may have a green tinge with a musty taste or odour. The water is generally suitable for recreational use, but people should use caution and avoid areas where the water appears to have a green tinge.
GREEN
Potentially toxic blue-green algae are detected at low levels. The blue-green algae do not pose a threat to recreational use.
Livestock Alerts
A High Alert for livestock drinking water is separate to the system of recreational alerts. It is put in place when there are high levels of potentially toxic blue-green algae that could affect livestock health.
During High Alerts, stock owners should seek alternative supplies of livestock drinking water.
More Information
General information on blue-green algae is available at WaterNSW.
Details on blue-green algae alerts is available at WaterNSW.