Algae is a natural part of the aquatic ecosystem, with most species safe or non-toxic. However, blue-green algae can produce toxins that may be damaging to humans, domestic animals and livestock that come in contact with the water.

In normal conditions, blue-green algae exist in low numbers and are part of a healthy ecosystem. However, under certain conditions, the algae can grow rapidly, producing an algal bloom. Blooms tend to be more common in the warmer months due to high levels of sunlight, low rainfall and high nutrients in waterways.

Council undertakes routine blue-green algae monitoring at a number of local waterbodies, including the Nepean River, over the warmer months and notifies the community if a red alert occurs. Residents and their pets should not come into physical contact with water in waterways signposted with blue-green algae warning signs.

To view current blue-green algae alerts, please refer to the Water Quality Map below:

Identifying Blue-Green Algae

There are many species of naturally occurring blue-green algae with some known to be potentially toxin producing. A blue-green algae bloom may be occurring in a waterbody if there are small green, red or brown flecks well-spaced or as a thick scum, with a green cloudiness/colour to the water and musty odour.

Some examples of blue-green algae in the Camden area are shown here:

It is easy to mistake harmless, free-floating aquatic plants for blue-green algae. Some of these common, native plants are featured in the Our Waterways webpage.

Council’s Water Quality Monitoring Program covers 19 environmental and recreational sites across the Local Government Area.

This includes four Nepean River sites, five creeks in different sub-catchments, and ten lakes in urban catchments. The monitoring program collects physical, chemical, microbiological and biological data from our waterways to monitor trends over time and identify the suitability of local waterways for recreational uses and environmental health. The water quality data also helps Council prioritise water quality improvement programs and waterway projects.

The water quality results can be viewed in the Our Waterway Health report which is updated every year.

Council also has five automatic water quality sensors which were installed as a trial of this new technology through the Western Parkland City Sensor project to monitor the effect of development and urban growth in the upper Wianamatta South Creek catchment. The project was delivered via matched grant funding through the Australian Government’s Smart Cities and Suburbs Program. Data collected from these sensors can be viewed on the Camden Data Portal.