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Far West Algal Reporting: Background

Algae populations in the Barwon-Darling river system are routinely monitored at thirteen locations (shown below) between Mungindi to Menindee through the Barwon-Darling Riverwatch Project.

Riverwatch sampling sites in Far Western NSW
(click on image for larger view)

Sample collection is managed by the Department and is conducted by departmental staff and those from some Shire councils as well as a community volunteer.

The primary objective of Riverwatch is to monitor algae and provide early warning of algal development. Increased sampling frequency and information collection and dissemination is triggered when a blue-green algal bloom occurs.

When a medium, high or very high alert is registered, users are advised to avoid waters in these areas. Landholders are advised to keep stock away from any affected areas, as blue-green algae are potentially toxic. NSW Health advises that any domestic use of surface water, including drinking, without treatment should be avoided. Blue-green algae levels may cause problems for recreational water use.
MANAGEMENT OF BLOOMS

What is Department’s role in blue-green algal management?

The Department, in conjunction with landholders and council staff, routinely monitors water supplies for blue-green algae, and other algal presence. The Department provides water testing and analysis services, as well as advice for landholders and other water users in the event of algal blooms in public waters.
Where can I get advice on managing blooms in my farm dam?

On-farm water supplies are the responsibility of NSW Department of Agriculture where they relate to farm business. Water quality testing is available for irrigation, stock and domestic purposes from the Department of Agriculture's Diagnostic and Analytical Services for a fee (Ring 02 6391 3800 for further details).

Local councils may be able to help with domestic supply management. Some commercial product suppliers offer solutions for farm water supplies affected by blue-green algae. The Department will provide telephone advice only but does not routinely inspect private properties.
CAUSES AND PREVENTION OF BLOOMS

What causes an algal bloom?

There is no single factor that causes an algal bloom. A combination of optimum factors such as the presence of good nutrients, warm temperatures and lots of light all encourage the natural increase in numbers of blue-green algae in our waterways.

Nature mostly takes care of the temperature and light, but the increased presence of nutrients such as phosphorous is largely due to poor farming practices such as high use of fertilisers and presence of livestock near water supplies, as well as effluent and run-off from towns and cities near waterways.

The ponding of water and reducing river flow rates tends to improve the light and sometimes the nutrient environment for algal growth making water turbulence a major factor in bloom development.

Pesticides and other chemicals may affect the natural grazers who would otherwise control algal growth and their presence increases the risk of blooms.
How can I prevent an algal bloom?

Algae need three things for optimal growth: light, nutrients and high temperatures.

Lowering the nutrients, light and temperature available to the blue-green algae in the water supply will help reduce algal growth. The speed at which water is flowing and mixing is important in controlling light and nutrient availability to algal cells.

Some prevention methods include keeping stock away from the farm dam or water supply; avoiding run-off into water supply from fertilisers and pesticides; taking some water treatment measures BEFORE a bloom starts; and if practical - changing mixing patterns or covering the dam/water supply to screen out light.

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© NSW Department of Natural Resources 2005

Caring for our Natural Resources Water Rural Water Management Search: [ HOME ]		Far West Algal Reporting: Background Algae populations in the Barwon-Darling river system are routinely monitored at thirteen locations (shown below) between Mungindi to Menindee through the Barwon-Darling Riverwatch Project. Riverwatch sampling sites in Far Western NSW (click on image for larger view) Sample collection is managed by the Department and is conducted by departmental staff and those from some Shire councils as well as a community volunteer. The primary objective of Riverwatch is to monitor algae and provide early warning of algal development. Increased sampling frequency and information collection and dissemination is triggered when a blue-green algal bloom occurs. When a medium, high or very high alert is registered, users are advised to avoid waters in these areas. Landholders are advised to keep stock away from any affected areas, as blue-green algae are potentially toxic. NSW Health advises that any domestic use of surface water, including drinking, without treatment should be avoided. Blue-green algae levels may cause problems for recreational water use. MANAGEMENT OF BLOOMS What is Department’s role in blue-green algal management? The Department, in conjunction with landholders and council staff, routinely monitors water supplies for blue-green algae, and other algal presence. The Department provides water testing and analysis services, as well as advice for landholders and other water users in the event of algal blooms in public waters. Where can I get advice on managing blooms in my farm dam? On-farm water supplies are the responsibility of NSW Department of Agriculture where they relate to farm business. Water quality testing is available for irrigation, stock and domestic purposes from the Department of Agriculture's Diagnostic and Analytical Services for a fee (Ring 02 6391 3800 for further details). Local councils may be able to help with domestic supply management. Some commercial product suppliers offer solutions for farm water supplies affected by blue-green algae. The Department will provide telephone advice only but does not routinely inspect private properties. CAUSES AND PREVENTION OF BLOOMS What causes an algal bloom? There is no single factor that causes an algal bloom. A combination of optimum factors such as the presence of good nutrients, warm temperatures and lots of light all encourage the natural increase in numbers of blue-green algae in our waterways. Nature mostly takes care of the temperature and light, but the increased presence of nutrients such as phosphorous is largely due to poor farming practices such as high use of fertilisers and presence of livestock near water supplies, as well as effluent and run-off from towns and cities near waterways. The ponding of water and reducing river flow rates tends to improve the light and sometimes the nutrient environment for algal growth making water turbulence a major factor in bloom development. Pesticides and other chemicals may affect the natural grazers who would otherwise control algal growth and their presence increases the risk of blooms. How can I prevent an algal bloom? Algae need three things for optimal growth: light, nutrients and high temperatures. Lowering the nutrients, light and temperature available to the blue-green algae in the water supply will help reduce algal growth. The speed at which water is flowing and mixing is important in controlling light and nutrient availability to algal cells. Some prevention methods include keeping stock away from the farm dam or water supply; avoiding run-off into water supply from fertilisers and pesticides; taking some water treatment measures BEFORE a bloom starts; and if practical - changing mixing patterns or covering the dam/water supply to screen out light.

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	© NSW Department of Natural Resources 2005