Water quality

Murrumbidgee Irrigation (MI) operates under a Combined Water Supply Work Approval and Water Use Approval 40CA403245 (Combined Approval) issued by the Department of Primary Industries,Water (DPI Water) and an Environmental Protection Licence 4651 (EPL 4651) issued by NSW EPA.

MI are required to monitor five licence discharge sites that have the potential to discharge waters to the Murrumbidgee River and Mirrool Creek Floodway. EPL 4651 provides a list of parameters and scheduled chemicals that are required to be monitored for each site during a discharge event. Water quality monitoring is carried out using applicable Australian standards and best practices.

Water quality samples are analysed by calibrated field monitoring equipment and/or a NATA accredited laboratory for data integrity.

We encourage all landholders to follow the manufacturer’s instructions for storage, use, transport and disposal of chemicals. Chemicals can be dangerous to humans and our environment. Store chemicals in a safe place and don’t mix or store chemicals in an unlabelled container. Please remember to notify any spills that may occur that could potentially cause harm to our environment.

Within the past financial year, the table below summaries the exceedances of notification and/or action levels under our EPL - 4651. Information for previous financial years can be found in the Annual Compliance Reports.





Level Triggered

 5/6/2024 LAG  Diuron   4.73  Action
 3/6/2024  LAG Diuron  24.5  Action
 31/5/2024  LAG  Diuron  1.06 Action 
 31/5/2024  LAG  Simazine  3.75 Notification
 17/5/2024 LAG  Diuron 2.04 Action
 10/5/2024  LAG  Diuron  1.14 Action 
 2/5/2024  LAG  Diuron  0.308  Notification
 29/4/2024  LAG  Simazine  6.73  Notification
 29/4/2024  LAG  Diuron  15.7  Action
 11/04/2024  LAG Diuron   67.9  Action
 03/01/2024  GMSRR Diuron  2.47 Action
 03/01/2024  GMSRR Metolachlor 0.696 Notification
 19/12/2023  GMSRR Diuron  18.5*  Action
 11/12/2023  LAG Diuron 0.311 Notification
 01/12/2023  GMSRR Diuron 1.46 Action
 03/10/2023  GMSRR Metolachlor 2.15 Notification
 26/09/2023  LAG Metolachlor  1.52  Notification
 25/09/2023  LAG Metolachlor  0.464  Notification
 07/07/2023  LAG Diuron  1.58   Action
 07/07/2023  LAG Metolachlor  0.816  Notification
 05/07/2023  LAG  Diuron  0.542  Notification
*Please note that the result is unreliable due to a breach in holding time.


Water quality test results for each licenced site can be viewed here: 

Blue-green algae 

Blue-green algae (BGA) is a photosynthetic organism that can produce poisons which harm humans and animals, with algal blooms most common during the warmer months.

MI proactively monitors BGA at key locations within our water supply system and relevant customers are notified of serious issues affecting water quality.

This monitoring program is in accordance with the contingency strategy developed by the NSW Government’s Murrumbidgee Regional Algal Coordinating Committee (RACC), and the information we provide on water use suitability meets the guidelines outlined by the NSW Department of Primary Industries.

Water samples are collected regularly from September to May each year, and the table below is immediately updated with the results. If the results indicate that water is not suitable for stock watering or domestic use (human contact), a ‘Stock Alert’ or ‘Domestic Alert’ is issued and all customers downstream of the detection points are notified of the alert via SMS or phonecall. Customers are also notified when the alert is lifted.

BGA results from monitoring points are an indication of BGA levels only, as BGA levels can change significantly during short time periods, particularly when temperatures increase and water movement is minimal.

Customers are advised to obtain independent advice regarding the suitability of their water for each intended purpose. 

Please note that regardless of the presence of BGA, water supplied by MI is not fit for human consumption.

For further information about blue-green algae, visit the NSW Department of Industries website.

Blue Green Algae test results

Location Stock Recreational Sample datE
Active Cell - Barren Box No Alert No Alert 10/07/2024
Intermediate Cell - Barren Box No Alert Amber Alert 10/07/2024
Wah Wah Main (Barden's Regulator) No Alert
Green Alert 10/07/2024
 Bray's Dam Storage  No Alert  No Alert


General information from NSW Department of Primary Industries (DPI) for blue-green algae can be accessed on their website www.dpi.nsw.gov.au. 

NSW DPI fact sheets for irrigation with blue-green algae affected water and treatment of algae can be accessed from the links below:

Stock Alert

Blue green algae results may not be suitable for stock watering. Customers downstream of the detection point will be notified of this 'Stock Alert' via SMS or phone.

Red Alert - Recreational (Domestic)
Blue green algae levels may not be suitable for recreational use, farm domestic use is not advised. Customers downstream of the detection point will be notified of a 'Domestic Alert' via SMS or phone.

Amber Alert - Recreational (Domestic)
Blue-green algae may be multiplying in numbers. This Alert does not restrict domestic or stock water use.

Green Alert - Recreational (Domestic)
Blue green algae are first detected in the water. This Alert does not restrict domestic or stock water use.

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General Enquiries

Phone: (02) 6962 0200
Email: info@mirrigation.com.au
Postal: Locked Bag 6010 Griffith NSW 2680

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