Water Management
NSW Algal Information
Algal alerts
Algal blooms can cause waters to be unsafe for recreation in both freshwater and marine water environments. Algal alerts are issued by Regional Algal Coordinating Committees (RACCs) who are responsible for local management of algal blooms.
For information on current alerts call the NSW algae hotline on 1800 999 457 or view the media releases.
The summary report below provides the most recent algal data collated by the RACCs from across NSW. Algal blooms may be present and not reported to the RACCs. Locations identified below were experiencing algal blooms at the date of the report. This report does not contain data from water storages managed by Water Supply Authorities where there is no public access.
NSW Health advises that any domestic use (including drinking) of surface water without appropriate treatment should be avoided at all times.
Recreational “Red alert” Algal Status Report: Updated 6 October 2009
The summary below is based on the most recent algal data available from the DWE laboratory and other sources. To sort this table alphabetically click on the column heading.
| Coordination area | Location | Major use | Trend | Management action |
|---|---|---|---|---|
| North Coast | Malpas Dam (near Armidale) | Recreation Town water supply |
No change | Signs erected continuing surveillance by Armidale Dumaresq Council |
| North Coast | Clarrie Hall Dam (near Murwillumbah) | Recreation Stock water and domestic Potable |
No change | Continued surveillance by Council |
| Central West | Lake Cargelligo | Irrigation Recreation Stock water and domestic |
No change | Continued monitoring, signs erected, media release |
| Central West | Windamere Reservoir | Irrigation Recreation Stock water and domestic |
No change | Continued monitoring by State Water, signs erected, media release |
| Central West | Burrendong Reservoir | Irrigation Recreation Stock water and domestic |
No change | Continued monitoring by State Water, signs erected, media release |
| Hunter | Marine Algae - Central Coast beaches, Hawkesbury River Mouth, Broken Bay | Recreation | Increasing | Continued surveillance, media release |
Red alerts are declared where algal cell numbers exceed the triggers identified in the Guidelines for Managing Risk in Recreational Waters released by the National Health and Medical Research Council.
Marine Algal Warning Central Coast Beaches, Hawkesbury River Mouth and Broken Bay Area
People are advised to avoid collection and eating of wild shellfish in these areas due to increased numbers of toxic marine algal species being observed. People are advised to avoid swimming in areas of discoloured water or foam.
Red Alert Definition:
These alert levels represent 'bloom' conditions. The water will appear green and may have strong, musty or organically polluted odours. Blue-green algae may be visible as clumps or as scums. The 'blooms' should be considered to be toxic to humans and animals, and the water should not be used for potable water supply (without prior treatment), stock watering, or for recreation.
Amber Alert Definition:
Blue green algae may be multiplying in numbers. The water may have a green tinge and musty or organic taste and odour. The water should be considered as unsuitable for potable use and alternative supplies or prior treatment of raw water for domestic purposes should be considered. The water may also be unsuitable for stock watering. The water remains suitable for recreational use.
All blue green algae 'blooms' should be considered as potentially toxic to humans and animals, and the water should not be used for potable water supply (without prior treatment), stock watering, or for recreation. NSW Health advises that any domestic use (including drinking) of surface water without treatment should be avoided at all times.
Eutrophication and algal blooms
Eutrophication is a process whereby rivers, lakes, estuaries or marine waters receive excess nutrients, particularly phosphorus but also nitrogen, that can stimulate rapid growth of algae and aquatic weeds. This can promote blooms of algae of which some can be toxic to humans and animals, and result in fish and stock deaths, minor gastro–intestinal complaints and skin irritations in humans. Algal blooms and growth of large water weed can also reduce dissolved oxygen in water resulting in fish kills. Nutrients can come from fertilizers applied to agriculture and lawns, erosion of soil containing nutrients and sewage treatment plant discharges and urban runoff.
National Cyanobacteria Workshop 2009
The National Cyanobacterial Workshop organised by the NSW Office of Water took place on August 12 and 13 at Parramatta, with around 110 attendees representing water management organisations, government agencies and research groups from all States and Territories. The Workshop was sponsored by the NSW Office of Water, the Sydney Catchment Authority and Water Quality Research Australia. Presentations were delivered by thirty-three speakers who gave updates on recent events and issues, current research, and monitoring, testing and treatment.