Menindee fish deaths follow up: Darling-Baaka River water tests

The Department of Planning and Environment (DPE) collected twenty-two water samples on 7, 18, 19, and 20 December 2023 at Menindee along the Darling-Baaka River, downstream along the lower Darling-Baaka River, and the Greater Darling Anabranch. 

Surface and bottom water samples were checked for nitrogen, phosphorus, total suspended solids, and ammonia. Surface water samples collected from Menindee Weir Pool on 7 December were also checked for algae and algal toxins. 

Pesticides and metals samples were not collected (see below).

Surface samples were collected at shallow sites (samples 1, 2, 3-9, 11-20). Surface and bottom samples were taken for five deep sites E1-5 (samples 3 to 7). 

The real-time data from four buoys deployed in the Darling-Baaka River by DPE under the River Health Project can be found here.

Sample locations

Water was sampled on 7 December from eight locations on the Darling-Baaka River at Menindee, and between 18 to 20 December from fourteen locations on the Darling-Baaka River at Menindee, downstream along the lower Darling-Baaka River, and along the Great Darling Anabranch. Surface samples were collected from the uppermost 50 cm of water, while bottom water was sampled from within 50 cm of the riverbed. The correlating sample identifications are given in brackets for reference to the full laboratory report data.

On 7 December 2023, eight sites in the Menindee Weir Pools in the Darling-Baaka River were sampled.

• Sample 1 (B1) (Surface only) – Lake Wetherell upstream of the Main Weir
• Sample 2 (B2) (Surface only) – Outlet of Lake Pamamaroo into Darling River
• Sample 3 (E1) (Surface and bottom water) – Upper weir pool
• Sample 4 (E2) (Surface and bottom water) – Mid weir pool
• Sample 5 (E3) (Surface and bottom water) – Menindee town
• Sample 6 (E4) (Surface and bottom water) – Downstream Menindee town
• Sample 7 (E5) (Surface and bottom water) – Lower weir pool downstream Lake Menindee inflow
• Sample 8 (B3) (Surface only) – Outlet of Lake Menindee into Darling-Baaka River

On 18 December 2023, one sample was collected from the Lower Darling-Baaka River between Weir 32 and Pooncarie.

• Sample 20 (E15) (Surface only) – Old wharf at Pooncarie

On 19 December 2023, three samples were collected from the Great Darling Anabranch region and three samples from the Lower Darling-Baaka River between Weir 32 and Pooncarie. 

• Sample 9 (B4) (Surface only) – Lake Cawndilla outlet into the Anabranch of Darling River 
• Sample 11 (E6.5) (Surface only) – Tandou Creek at Tandou Woolshed Rd (incorporating inflows from Kangaroo Lake) 
• Sample 12 (E7) (Surface only) – Tandou Creek at Packers Crossing (incorporating inflows from Packers Lake) 
• Sample 16 (E11) (Surface only) – Bindara Station Reach 
• Sample 18 (E13) (Surface only) – Coona Point Reach 
• Sample 19 (E14) (Surface only) – Mullingar Station Reach 

On 20 December 2023, three samples were collected from the Menindee Weir Pools in the Darling-Baaka River and four samples from the Lower Darling-Baaka River between Weir 32 and Pooncarie 

• Sample 1 (B1) (Surface only) – Lake Wetherell upstream of the Main Weir 
• Sample 2 (B2) (Surface only) – Outlet of Lake Pamamaroo into Darling River 
• Sample 8 (B3) (Surface only) – Outlet of Lake Menindee into Darling-Baaka River 
• Sample 13 (E8) (Surface only) – Kinchega National Park upper 
• Sample 14 (E9) (Surface only) – Kinchega National Park mid (incorporating inflows from Emu Lake) 
• Sample 15 (E10) (Surface only) – Kinchega National Park lower (upstream of Anabranch offtake) 
• Sample 17 (E12) (Surface only) – Karoola Station Reach 

Figure 1: Sample locations where samples were taken December 2023. See Figures 2 & 3 below for more detail. Note, not all locations were sampled this round.   

Figure 2: Sample locations for the Menindee Weir Pools region along the Darling-Baaka River.

Figure 3: Sample locations for the Great Darling Anabranch and lower Darling-Baaka River between Weir 32 and Pooncarie regions. Note, not all locations were sampled this round.   

More sampling

The DPE are conducting regular water quality monitoring on the Darling-Baaka River from upstream of Menindee to Pooncarie. The test results from these samples will also be published on this website. The format for reporting will be changing for samples taken from 2024 onwards. Future reports will consist of 3-monthly summaries of water quality, with test results still available on this website.

Through the River Health Project, DPE Science have installed four telemetered loggers which collect real-time data on water quality in the project area. View the real-time water quality data from the River Health Project here. 

In-field measurements – 7 December

At the time of sampling, the DPE collected in-field measurements for pH, dissolved oxygen, conductivity, temperature, and turbidity.  

pH was outside the guideline value for some samples in the Menindee and Lower Darling-Baaka regions but are consistent with previous measurements.    

All parameters were within the expected ranges. 

In-field measurements – 18 to 20 December

At the time of sampling, the DPE collected in-field measurements for pH, dissolved oxygen, conductivity, temperature, and turbidity.  

pH was outside the guideline value for some samples in the Menindee and Lower Darling-Baaka regions but are consistent with previous measurements. 

All parameters were within the expected ranges. 

Nitrogen, phosphorus and ammonia

Sample results show that total nitrogen and total phosphorous are higher than the acceptable levels given for lowland river ecosystems in NSW (ANZG 2018, which are in agreement with the regionally specific set of guideline values for the Murray-Darling outlined in the Basin Plan 2012).

For samples taken on 7 December, the total nitrogen was detected up to 2 times higher than the guideline value while total phosphorus was detected at up to 4 times higher. Total nitrogen for samples taken between the 18 to 20 December was up to 2 times higher than the guideline value while total phosphorus was detected at up to 5 times higher. Algal blooms are possible if these nutrients remain elevated.

Bacteria convert nitrogen compounds such as ammonia into nitrite and nitrate. Some of these compounds can harm aquatic organisms. The average ammonia was below the Australian and New Zealand water quality guidelines for toxicity in all samples. While the levels would not be expected to be harmful to fish, the ammonia could promote growth in algae and macrophytes. The ammonia is likely to be from river sources including rotting fish and flood organic matter rather than diffuse inputs from surrounding land.  

Nutrient data for samples 1, 13, 16, 17, 19, and 20 have been removed from analysis due to possible compromise in the sample.  

References

ANZG (2018), Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia. Available at www.waterquality.gov.au/anz-guidelines 

Basin Plan (2012), Schedule 11, Water Act 2007, Murray-Darling Basin Authority, Commonwealth of Australia  

The Department of Planning and Environment (DPE) collected seventeen water samples between 7 to 9 November 2023 at Menindee along the Darling-Baaka River, downstream along the lower Darling-Baaka River, and along the Great Darling Anabranch.

Surface and bottom water samples were checked for excess nitrogen, phosphorus, and ammonia. Surface samples were collected at shallow sites (samples 1, 2, 6-8 and 9-20). Surface and bottom samples were collected at three deep sites (samples 3 to 5).

Surface water samples were also checked for pesticides, algae and algae toxins. Samples 9 to 12 and 16 to 20 were additionally examined for algae identification.

Total metals were tested in all surface water samples at all sites and bottom water samples in Samples 3, 4, and 5.

• See the real-time data from the smart buoys deployed in the Darling-Baaka River by DPE under the River Health Project

Sample locations

On 7 November 2023, eight samples were collected from the Menindee Weir Pool. The correlating sample identifications are given in brackets for reference to the full laboratory report data. Surface samples were collected from the uppermost 50 cm of water, while bottom water samples were obtained from the layer of water situated within 50 cm above the sediment bed.

• Sample 1 (B1) (surface) – Lake Wetherell upstream of the Main Weir
• Sample 2 (B2) (surface) – Outlet of Lake Pamamaroo into Darling River
• Sample 3 (E1) (surface and bottom)– Upper weir pool
• Sample 4 (E2) (surface and bottom) – Mid weir pool
• Sample 5 (E3) (surface and bottom) – Menindee town
• Sample 6 (E4) (surface) – Downstream Menindee town
• Sample 7 (E5) (surface) – Lower weir pool downstream Lake Menindee inflow
• Sample 8 (B3) (surface) – Outlet of Lake Menindee into Darling-Baaka River

On 9 November 2023, nine samples were collected in the Great Darling Anabranch region and Lower Darling-Baaka River between Weir 32 and Pooncarie.

• Sample 9 (B4) (surface) – Lake Cawndilla outlet into the anabranch of Darling River
• Sample 10 (E6) (surface) – Redbank Creek upstream of Cawndilla Channel confluence
• Sample 11 (E6.5) (surface) – Tandou Creek at Tandou Woolshed Rd (incorporating inflows from Kangaroo Lake)
• Sample 12 (E7) (surface) – Tandou Creek at Packers Crossing (incorporating inflows from Packers Lake)
• Sample 16 (E11) (surface) – Bindara Station Reach
• Sample 17 (E12) (surface) – Karoola Station reach
• Sample 18 (E13) (surface) – Coona Point reach
• Sample 19 (E14) (surface) – Mullingar Station reach
• Sample 20 (E15) (surface) – Old wharf at Pooncarie

Figure 1: Sample locations where samples were taken between 7 and 9 November 2023. See Figures 2 and 3 below for more detail. Note, not all locations were sampled this round. 

Figure 2: Sample locations for the Menindee Weir Pools region along the Darling-Baaka River

Figure 3: Sample locations for the Great Darling Anabranch and lower Darling-Baaka river between Weir 32 and Pooncarie regions. Note, not all locations were sampled this round. 

More sampling

The DPE are conducting regular water quality monitoring on the Darling-Baaka River from upstream of Menindee to Pooncarie. The test results from these samples will also be published on this website. Through the River Health Project, DPE Science have installed four telemetered loggers which collect real-time data on water quality in the project area.

• View the real-time water quality data from the River Health Project

In-field measurements

At the time of sampling, the DPE collected in-field measurements for pH, dissolved oxygen, conductivity, temperature, and turbidity. All samples collected on the 9 November (Samples 9-12, 16-20) were impacted by a probe malfunction resulting in no pH measurement. The pH sensor was replaced for subsequent trips.

pH was outside the guideline value for some samples in the Menindee and Lower Darling-Baaka regions but results were consistent with previous sampling events.

Dissolved oxygen was low in samples collected from Redbank Ck upstream of Cawndilla Channel confluence (Sample 10 - E6), with a measurement of 2.4 mg/L.  This site had ceased flow at the time of the sampling and recorded high turbidity and chlorophyll concentrations, indicating the presence of a large algal bloom and the potential for fish harm to occur.  Under these conditions, dissolved oxygen concentrations can vary widely over a 24-hour period due to photosynthesis during the light and respiration during the dark.

 nm = not measured

Nitrogen, phosphorus and ammonia

Sample results show that total nitrogen and total phosphorus are higher than the acceptable levels given for lowland river ecosystems in NSW (ANZG 2018, which are in agreement with the regionally specific set of guideline values for the Murray-Darling outlined in the Basin Plan 2012). Total nitrogen was detected up to 3 times higher than the guideline value while total phosphorus was detected at up to 5 times higher. Algal blooms are possible if these nutrients remain elevated.

Bacteria convert nitrogen compounds such as ammonia into nitrite and nitrate. Some of these compounds can harm aquatic organisms. Ammonia was below the Australian and New Zealand water quality guidelines for toxicity. While the levels would not be expected to be harmful to fish, the ammonia could promote growth in algae and macrophytes. The ammonia is likely to be from river sources including rotting fish and flood organic matter rather than diffuse inputs from surrounding land.

Algae and algal toxins

Blue-green algae were detected in all samples, but potentially toxic blue-green algae were detected in only six of the surface water samples (samples 11 and 16 to 20). The algal toxin Cylindrospermopsin was not detected.

Pesticides

Sixteen samples were screened for more than 100 pesticides in November (Sample 1 was not tested). The herbicide atrazine was found in very low concentrations (ranging from 0.11 to 0.27 µg/L). The concentrations detected were below the ecological water quality  guideline of 0.7 µg/L set for a 99% protection level (ANZG 2018).  Atrazine is a widely used herbicide which is used to control grass and broadleaved weeds in crops.  High concentrations of atrazine can cause negative environmental effects but given the low concentrations detected in November, it is not likely to have caused biological stress.

No other pesticides or herbicides were detected.

Metals

Many metals are vital for humans and animals to stay healthy and only pose a risk if they are found at high levels in the environment. Total metals have been compared to recreational water quality guidelines and ecological water quality guidelines as per the National Health and Medical Research Council (NHMRC) recreational and Australian and New Zealand Water Quality (ANZG) guidelines, respectively. Total metals provide a more conservative estimate of exposure from recreational use. The use of total metal concentrations for ecological assessments is conservative as it’s overestimating the bioavailable fraction of the metal (the part that is toxic to organisms).

Total chromium was slightly above the level set to protect water life in the Menindee Lake outflow (sample 8; site B3) and at the site immediately downstream of the Menindee Creek junction (sample 7; site E5), as well as at sites downstream of weir 32 (samples 16-18).  Total copper was slightly above the level set to protect water life in seven of the samples with no apparent spatial trends in exceedances. All other metals were under the levels set to protect water life.  Full metal results are provided in the below table.

References

ANZG (2018), Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia. Available at www.waterquality.gov.au/anz-guidelines

Basin Plan (2012), Schedule 11, Water Act 2007, Murray-Darling Basin Authority, Commonwealth of Australia

Atrazine in freshwater and marine water (2000), Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia. Available at: Atrazine in freshwater and marine water (waterquality.gov.au)

Atrazine Chemical Review (2008) Australian Pesticides and Veterinary Medicines Authority. Available at: https://www.apvma.gov.au/chemicals-and-products/chemical-review/listing/atrazine.

NHMRC (2008), Guidelines for managing risks in recreational waters, Australian Government National Health and Medical Research Council

The Department of Planning and Environment (DPE) collected eleven water samples between 11 to 12 October 2023 at Menindee, and further downstream along the Darling-Baaka River.

Surface and bottom water samples were checked for excess nitrogen, phosphorus, and ammonia. Surface water samples were also checked for the presence of algae and algal toxins.

Surface samples were taken for shallow sites (samples 1 - 8 and 13 -14). Surface and bottom samples were taken for deep sites (samples 3 to 7).

• See the real-time data from the smart buoys deployed in the Darling-Baaka River by DPE under the River Health Project

Samples were not collected from the Great Darling Anabranch, and some of the routine locations along the Lower Darling Baaka during this sampling round (samples 9 to 12 and 16 to 20).

Sample locations

On 11 October 2023, eight samples were collected from the Menindee Weir Pools in the Darling-Baaka River. The correlating sample identifications are given in brackets for reference to the full laboratory report data. Surface samples were collected from the uppermost 50 cm of water, while bottom water samples were obtained from the layer of water situated within 50 cm above the sediment bed.

• Sample 1 (B1) – Lake Wetherell upstream of the Main Weir (Surface)
• Sample 2 (B2) – Outlet of Lake Pamamaroo into Darling River (Surface)
• Sample 3 (E1) – Upper weir pool (Surface and Bottom)
• Sample 4 (E2) – Mid weir pool (Surface and Bottom)
• Sample 5 (E3) – Menindee town (Surface and Bottom)
• Sample 6 (E4) – Downstream Menindee town (Surface and Bottom)
• Sample 7 (E5) – Lower weir pool downstream Lake Menindee inflow (Surface and Bottom)
• Sample 8 (B3) – Outlet of Lake Menindee into Darling-Baaka River (Surface)

On 12 October 2023, three samples were collected from the Lower Darling-Baaka River between Weir 32 and Pooncarie.

• Sample 13 (E8) – Kinchega National Park upper (Surface)
• Sample 14 (E9) – Kinchega National Park mid (incorporating inflows from Emu Lake) (Surface)
• Sample 15 (E10) – Kinchega National Park lower (upstream of Anabranch offtake) (Surface)

Figure 1: Sample locations where samples were taken between 11 and 12 October 2023. See Figures 2 and 3 below for more detail. Note, not all locations were sampled this round.

Figure 2: Sample locations for the Menindee Weir Pools region along the Darling-Baaka River

Figure 3: Sample locations for the Great Darling Anabranch and lower Darling-Baaka river between Weir 32 and Pooncarie regions. Note, not all locations were sampled this round.

More sampling

The DPE are conducting regular water quality monitoring on the Darling-Baaka River from upstream of Menindee to Pooncarie. The test results from these samples will also be published on this website. Through the River Health Project, DPE Science have installed four telemetered loggers which collect real-time data on water quality in the project area.

• View the real-time water quality data from the River Health Project

In-field measurements

At the time of sampling, the DPE collected in-field surface measurements for pH, dissolved oxygen, conductivity, temperature, and turbidity.

pH was outside the guideline value for some samples in the Menindee and Lower Darling-Baaka regions.

All other parameters were within the expected ranges.

Nitrogen, phosphorus, and ammonia

Sample results show that total nitrogen and total phosphorus are higher than the acceptable levels given for lowland river ecosystems in NSW (ANZG 2018, which are in agreement with the regionally specific set of guideline values for the Murray-Darling outlined in the Basin Plan 2012). Total nitrogen was detected up to 2 times higher than the guideline value while total phosphorus was detected at up to 4 times higher. Algal blooms are possible if these nutrients remain elevated.

Bacteria convert nitrogen compounds such as ammonia into nitrite and nitrate. These compounds can harm aquatic organisms. Ammonia was below the Australian and New Zealand water quality guidelines for toxicity. While the levels would not be expected to be harmful to fish, the ammonia could promote growth in algae and macrophytes. The ammonia is likely to be from river sources including rotting fish and flood organic matter rather than diffuse inputs from surrounding land.

References

ANZG (2018), Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia. Available at www.waterquality.gov.au/anz-guidelines

Basin Plan (2012), Schedule 11, Water Act 2007, Murray-Darling Basin Authority, Commonwealth of Australia

The Department of Planning and Environment (DPE) collected thirteen water samples between 13 to 14 September 2023 at Menindee, and further downstream along the lower Darling-Barka River.

Surface and bottom water samples were checked for excess nitrogen, phosphorus, and ammonia. Surface water samples were also checked for algae and algal toxins.

Surface water samples were collected at shallow sites (samples 1, 2, 8, and 16 to 20). Surface and bottom samples were collected at deep sites (samples 3 to 7).

Samples were not collected from the Great Darling Anabranch, and some of the routine locations along the Lower Darling Barka during this sampling round (samples 9 to 15).

Sample locations

On 13 to 14 September 2023, thirteen samples were collected from the Menindee Weir Pools and the lower Darling-Barka River. The correlating sample identifications are given in brackets for reference to the full laboratory report data. Surface samples were collected from the uppermost 50 cm of water, while bottom water samples were obtained from the layer of water situated within 50 cm above the sediment bed.

• Sample 1 (B1) – Lake Wetherell upstream of the Main Weir (Surface)
• Sample 2 (B2) – Outlet of Lake Pamamaroo into Darling River (Surface)
• Sample 3 (E1) – Upper weir pool (Surface and Bottom)
• Sample 4 (E2) – Mid weir pool (Surface and Bottom)
• Sample 5 (E3) – Menindee town (Surface and Bottom)
• Sample 6 (E4) – Downstream Menindee town (Surface and Bottom)
• Sample 7 (E5) – Lower weir pool downstream Lake Menindee inflow (Surface and Bottom)
• Sample 8 (B3) – Outlet of Lake Menindee into Darling-Barka River (Surface)
• Sample 16 (E11) – Bindara Station Reach (Surface)
• Sample 17 (E12) – Karoola Station Reach (Surface)
• Sample 18 (E13) – Coona Point Reach (Surface)
• Sample 19 (E14) – Mullingar Station Reach (Surface)
• Sample 20 (E15) – Old wharf at Pooncarie (Surface)

More sampling

The DPE are conducting regular water quality monitoring on the Darling-Barka River from upstream of Menindee to Pooncarie. The test results from these samples will also be published on this website. Through the River Health Project, DPE Science have installed four telemetered loggers which collect real-time data on water quality in the project area. 

• View the real-time water quality data from the River Health Project 

In-field measurements

At the time of sampling, the DPE collected surface in-field measurements for pH, dissolved oxygen, conductivity, temperature, and turbidity.

pH was outside the guideline value for some samples in the Menindee and Lower Darling-Barka regions.

All parameters were within the expected ranges.

nm = Not measured

Nitrogen, Phosphorus, and Ammonia

Surface and bottom sample results show that total nitrogen and total phosphorous are higher than the acceptable levels given for lowland river ecosystems in NSW (ANZG 2018, which are in agreement with the regionally specific set of guideline values for the Murray-Darling outlined in the Basin Plan 2012). Total nitrogen was detected up to 2.5 times higher than the guideline value while total phosphorous was detected at up to 3.5 times higher. Algal blooms are possible if these nutrients remain elevated.

Bacteria convert nitrogen compounds such as ammonia into nitrite and nitrate. These compounds can harm aquatic organisms. The ammonia was also below the Australian and New Zealand water quality guidelines for toxicity. While the levels would not be expected to be harmful to fish, the ammonia could promote growth in algae and macrophytes. The ammonia is likely to be from river sources including rotting fish and flood organic matter rather than diffuse inputs from surrounding land.

References

ANZG (2018), Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia. Available at www.waterquality.gov.au/anz-guidelines

Basin Plan (2012), Schedule 11, Water Act 2007, Murray-Darling Basin Authority, Commonwealth of Australia

The Department of Planning and Environment (DPE) collected twenty water samples between 22 to 24 August 2023 at Menindee along the Darling-Barka River, downstream along the lower Darling-Barka River, and along the Great Darling Anabranch.

Samples were checked for excess nitrogen and phosphorus, ammonia, algae and algal toxins. Surface and bottom samples were taken.

Pesticides and metals samples were not collected (see below).

Sample locations

Water was sampled between 22 and 24 August 2023 from twenty locations on the Darling-Barka River at Menindee, downstream along the lower Darling-Barka River, and along the Great Darling Anabranch. Surface samples were collected from the uppermost 50 cm of water, while bottom water samples were obtained from the layer of water situated within 50 cm above the sediment bed.

On 22 August 2023, eight samples were collected from the Menindee Weir Pools in the Darling-Barka River. The correlating sample identifications are given in brackets for reference to the full laboratory report data.

• Sample 1 (B1) – Lake Wetherell upstream of the Main Weir (surface)
• Sample 2 (B2) – Outlet of Lake Pamamaroo into Darling River (surface)
• Sample 3 (E1) – Upper weir pool (surface and bottom)
• Sample 4 (E2) – Mid weir pool (surface and bottom)
• Sample 5 (E3) – Menindee town (surface and bottom)
• Sample 6 (E4) – Downstream Menindee town (surface and bottom)
• Sample 7 (E5) – Lower weir pool downstream Lake Menindee inflow (surface and bottom)
• Sample 8 (B3) – Outlet of Lake Menindee into Darling-Barka River (surface)

On 23 August 2023, four surface samples were collected from the Great Darling Anabranch region and three surface samples from the Lower Darling-Barka River between Weir 32 and Pooncarie.

• Sample 9 (B4) – Lake Cawndilla outlet into the anabranch of Darling River
• Sample 10 (E6) – Redbank Creek upstream of Cawndilla Channel confluence
• Sample 11 (E6.5) – Tandou Creek at Tandou Woolshed Rd (incorporating inflows from Kangaroo Lake)
• Sample 12 (E7) – Tandou Creek at Packers Crossing (incorporating inflows from Packers Lake)
• Sample 13 (E8) – Kinchega National Park upper
• Sample 14 (E9) – Kinchega National Park mid (incorporating inflows from Emu Lake)
• Sample 15 (E10) – Kinchega National Park lower (upstream of Anabranch offtake)

On 24 August 2023, five surface samples were collected from the Lower Darling-Barka River between Weir 32 and Pooncarie.

• Sample 16 (E11) – Bindara Station Reach
• Sample 17 (E12) – Karoola Station reach
• Sample 18 (E13) – Coona Point reach
• Sample 19 (E14) – Mullingar Station reach
• Sample 20 (E15) – Old wharf at Pooncarie

More sampling

The DPE are conducting regular water quality monitoring on the Darling-Barka River from upstream of Menindee to Pooncarie as well as the Great Darling Anabranch. The test results from these samples will also be published on this website. Through the River Health Project, DPE Science have installed four telemetered loggers which collect real-time data on water quality in the project area.

• View the real-time water quality data from the River Health Project  

In-field measurements

At the time of sampling, the DPE collected in-field surface measurements for pH, dissolved oxygen, conductivity, temperature and turbidity.

pH was outside the guideline value for some samples in the Great Darling Anabranch and Lower Darling-Barka regions.

Dissolved oxygen at the Redbank Ck upstream of Cawndilla Channel confluence was 3.9mg/L. Native fish and other large aquatic organisms require at least 2mg/L of dissolved oxygen to survive but may begin to suffer if levels are below 4 to 5mg/L for prolonged periods.

Sample 12, collected from the Great Darling Anabranch region at Tandou Ck at Packers Crossing, was super-saturated with oxygen and had very high nutrient concentrations. When water holds as much dissolved oxygen as it can at a specific temperature, it is said to be saturated with oxygen. The oxygen saturation and nutrient load is likely due to a cyanobacteria bloom at the time. The sample location is adjacent to a complex wetland system and is prone to high variability in water quality.

All other parameters were within the expected ranges.

mm = not measured      nr = no reliable measurement

Nitrogen, Phosphorus, and Ammonia

Sample results show that total nitrogen and total phosphorous are higher than the acceptable levels given for lowland river ecosystems in NSW (ANZG 2018, which are in agreement with the regionally specific set of guideline values for the Murray-Darling outlined in the Basin Plan 2012). The average total nitrogen was detected to be up to three times higher than the guideline value while the average total phosphorous was detected at up to five times higher. Algal blooms are possible if these nutrients remain elevated.

Bacteria convert nitrogen compounds such as ammonia into nitrite and nitrate. These compounds can harm aquatic organisms. Ammonia was well below the Australian and New Zealand water quality guidelines for toxicity. While the levels would not be expected to be harmful to fish, the ammonia could promote growth in algae and macrophytes. The ammonia is likely to be from river sources including rotting fish and flood organic matter rather than diffuse inputs from surrounding land.

References

ANZG (2018), Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia. Available at www.waterquality.gov.au/anz-guidelines

Basin Plan (2012), Schedule 11, Water Act 2007, Murray-Darling Basin Authority, Commonwealth of Australia

The Department of Planning and Environment (DPE) collected 8 water and 15 sediment samples between 8 to 9 August 2023 at Menindee along the Darling-Barka River.

Samples were checked for excess nitrogen and phosphorus, ammonia, and algae. Sediment samples were checked for metals and pesticides.

The remaining 12 sites usually collected from the Great Darling Anabranch and lower Darling-Barka River were not sampled due to sampling teams being assigned to collect sediment samples at Menindee along the Darling-Barka.  The sediment sampling sites are marked in Figure 1.

Pesticide and metal analyses in water have been completed routinely between March and July 2023 with no pesticide detections, and all metals except copper measuring below levels set to protect water life. Copper has consistently measured above the level set to protect water life in various samples across the regions, yet well below the level harmful to fish. For these reasons, both pesticides and metals sampling have been reduced to occur approximately every three months. All other routine analyses will continue at the same frequency.

Sample locations

On 8 August 2023, 15 sediment samples were collected from the Menindee Weir Pools, to understand how sediment effects oxygen concentrations in the water column, and the accumulation of potential contaminants (metals, pesticides and herbicides) after the floods. Fifteen sites were sampled along the weir pool, between the outlet of Lake Pamamaroo into Darling River and Lower weir pool downstream Lake Menindee inflow. Seven of the fifteen sediment samples aligned with previous water sampling sites (samples 2-8).  Samples were analysed for sediment properties such as grain size, stable isotopes, metals and pesticides.

On 9 August 2023, eight water samples were collected from the Menindee Weir Pools in the Darling-Barka River (samples 1-8). The correlating sample identifications are given in brackets for reference to the full laboratory report data.

• Sample 1 (B1) (water only) – Lake Wetherell upstream of the Main Weir
• Sample 2 (B2) (sediment and water) – Outlet of Lake Pamamaroo into Darling River
• Sample 3 (E1) (sediment and water) – Upper weir pool
• Sample 4 (E2) (sediment and water) – Mid weir pool
• Sample 5 (E3) (sediment and water)  – Menindee town
• Sample 6 (E4) (sediment and water) – Downstream Menindee town
• Sample 7 (E5) (sediment and water) – Lower weir pool downstream Lake Menindee inflow
• Sample 8 (B3) (sediment and water) – Outlet of Lake Menindee into Darling-Barka River
• Sample 21 (P1) (sediment only) – Downstream of Menindee Main Weir
• Sample 22 (P2) (sediment only) – Upstream of upper weir sample site/li>
• Sample 23 (P3) (sediment only) – Weir pool north of Menindee Hut Waterhole
• Sample 24 (P4) (sediment only) – Northeast of Orchard Rd upstream of mid weir pool sample site
• Sample 25 (P5) (sediment only) –Northeast of Menindee golf club downstream of mid weir pool site
• Sample 26 (P6) (sediment only) – Southeast of loop road
• Sample 27 (P7) (sediment only) – Downstream and close to the outlet of Lake Menindee into the Darling-Barka River
• Sample 28 (P8) (sediment only) – In between outlet of Lake Menindee and Lower Weir Pool site

More sampling

The DPE are conducting regular water quality monitoring on the Darling-Barka River from upstream of Menindee to Pooncarie as well as the Great Darling Anabranch. The test results from these samples will also be published on this website.

Through the Darling Barka River Health Project, DPE Science have installed four telemetered loggers which collect real-time data on water quality in the project area.

• View the real-time water quality data from the River Health Project

In-field measurements

At the time of sampling, the DPE collected in-field measurements for pH, dissolved oxygen, conductivity, temperature, and turbidity.

All parameters were within the expected ranges.

nm = Not measured this round

Nitrogen, Phosphorus and Ammonia

Sample results show that total nitrogen and total phosphorous are higher than the acceptable levels given for lowland river ecosystems in NSW (ANZG 2018, which agree with the regionally specific set of guideline values for the Murray-Darling outlined in the Basin Plan 2012). Total nitrogen was detected at up to two times higher than the guideline value while total phosphorous was detected at up to seven times higher. Algal blooms are possible if these nutrients remain elevated.

Bacteria convert nitrogen compounds such as ammonia into nitrite and nitrate. These compounds can harm aquatic organisms. Ammonia was well below the Australian and New Zealand water quality guidelines for toxicity. While the levels would not be expected to be harmful to fish, the ammonia could promote growth in algae and macrophytes. The ammonia is likely to be from river sources including rotting fish and flood organic matter rather than diffuse inputs from surrounding land.

Algae

There were positive detections in all samples for blue-green algae. However, only the blue-green algae detections found in sample 3, 6 and 7 were considered potentially toxic.

Sediment Contaminants

Metals and pesticides were compared to ANZG (2018) default sediment quality guideline values (DGV) and high guideline values (GV-High).

The metals, with guidelines listed in ANZG (2018), had measured concentrations below all sediment quality guideline (DGV) threshold values except nickel. Nickel measured slightly higher than the DGV for some sites, but all these sites recorded well below the high guideline values (GV-High). This is suggesting there is a low risk of effects to the Darling-Barka aquatic ecosystem associated with post-flood deposition or localised inputs. 

Sediment carbon contents (0.1 - 2.0%) were in the low to moderate range for riverine sediments  and did not indicate excessive organic enrichment.  Sediment carbon and nitrogen stable isotopes were measured to provide an indication of organic matter sources.  Stable isotope values were not consistent with the accumulation of fish biomass, and in contrast suggested that main sources of organic matter to sediments was phytoplankton detritus and terrestrial organic matter.  

A range of pesticides were analysed in the collected sediment samples.  No pesticides were detected, therefore the risk posed by these contaminants is likely to be low, however, in some cases the detection limit exceeds the DGVs.

References

ANZG (2018), Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT (Australian Capital Territory), Australia. Available at www.waterquality.gov.au/anz-guidelines

Basin Plan (2012), Schedule 11, Water Act 2007, Murray-Darling Basin Authority, Commonwealth of Australia

The Department of Planning and Environment (DPE) collected nineteen water samples between 1 to 3 August 2023 at Menindee along the Darling-Barka River, downstream along the lower Darling-Barka River, and along the Great Darling Anabranch.

Sampling was reduced during this period following direction to investigate further reported fish deaths.  All samples were checked for ammonia, excess nitrogen and phosphorus. Samples from Menindee along the Darling-Barka River were also checked for pesticides, algae and algal toxins. Metals were unable to be reported on for this round due to a laboratory error. Future monitoring and reporting will include metals.

Pesticide and metal analyses have been completed routinely between March and July 2023 with no pesticide detections, and all metals except copper measuring below levels set to protect water life. Copper has consistently measured above the level set to protect water life in various samples across the regions, yet well below the level harmful to fish. For these reasons, both pesticides and metals analysis will continue on a less regular basis. All other routine analyses will continue at the same frequency.

One of the samples usually collected from the lower Darling-Barka region was unable to be sampled on this occasion, interrupted by road closures due to inclement weather.

Sample locations

Water was sampled between 1 and 3 August 2023 from nineteen locations on the Darling-Barka River at Menindee, downstream along the lower Darling-Barka River, and along the Great Darling Anabranch.

On 1 August 2023, eight samples were collected from the Menindee Weir Pools in the Darling-Barka River. The correlating sample identifications are given in brackets for reference to the full laboratory report data.

• Sample 1 (B1) – Lake Wetherell upstream of the Main Weir
• Sample 2 (B2) – Outlet of Lake Pamamaroo into Darling River
• Sample 3 (E1) – Upper weir pool
• Sample 4 (E2) – Mid weir pool
• Sample 5 (E3) – Menindee town
• Sample 6 (E4) – Downstream Menindee town
• Sample 7 (E5) – Lower weir pool downstream Lake Menindee inflow
• Sample 8 (B3) – Outlet of Lake Menindee into Darling-Barka River

On 2 August 2023, two samples were collected from the Great Darling Anabranch region.

• Sample 11 (E6.5) – Tandou Creek at Tandou Woolshed Rd (incorporating inflows from Kangaroo Lake)
• Sample 12 (E7) – Tandou Creek at Packers Crossing (incorporating inflows from Packers Lake)

On 3 August 2023, two samples were collected from the Great Darling Anabranch region and seven samples were collected from the Lower Darling-Barka River between Weir 32 and Pooncarie.

• Sample 9 (B4) – Lake Cawndilla outlet into the anabranch of Darling River
• Sample 10 (E6) – Redbank Creek upstream of Cawndilla Channel confluence
• Sample 13 (E8) – Kinchega National Park upper
• Sample 14 (E9) – Kinchega National Park mid (incorporating inflows from Emu Lake)
• Sample 16 (E11) – Bindara Station reach
• Sample 17 (E12) – Karoola Station reach
• Sample 18 (E13) – Coona Point reach
• Sample 19 (E14) – Mullingar Station reach
• Sample 20 (E15) – Old wharf at Pooncarie

Sample 15 (E10) Kinchega National Park lower was unable to be sampled on this occasion, due to accessibility issues following heavy rain.

More sampling

The DPE are conducting regular water quality monitoring on the Darling-Barka River from upstream of Menindee to Pooncarie as well as the Great Darling Anabranch. The test results from these samples will also be published on this website.

In-field measurements

At the time of sampling, the DPE collected in-field measurements for pH, dissolved oxygen, conductivity, temperature and turbidity.

pH was outside the guideline value for all samples in the Great Darling Anabranch region. 

All other parameters were within the expected ranges.

Nitrogen, phosphorus and ammonia

Sample results show that total nitrogen and total phosphorous are higher than the acceptable levels given for lowland river ecosystems in NSW (ANZG 2018, which are in agreement with the regionally specific set of guideline values for the Murray-Darling outlined in the Basin Plan 2012). Total nitrogen was detected at up to five times higher than the guideline value while total phosphorous was detected at up to eight times higher, with the exception of Sample 12 which was twelve times higher.  Algal blooms are possible if these nutrients remain elevated.

Bacteria convert nitrogen compounds such as ammonia into nitrite and nitrate. These compounds can harm aquatic organisms. Ammonia was well below the Australian and New Zealand water quality guidelines for toxicity. While the levels would not be expected to be harmful to fish, the ammonia could promote growth in algae and macrophytes. The ammonia is likely to be from river sources including rotting fish and flood organic matter rather than diffuse inputs from surrounding land.

Algae and algal toxins

There were positive detections in all samples for blue-green algae in the Menindee region. However, only the blue-green algae detections found in samples 3 and 8 were considered potentially toxic. The algal toxin Cylindrospermopsin was not detected in any samples from this region.

The algae levels detected fall within the ‘amber’ to ‘red’ alert levels. A red alert is in place along parts of the lower Darling-Barka River.

A red alert and amber alert is in place along at Menindee and further downstream, as of 3 November 2023. See WaterNSW for information about alerts.

Pesticides

As noted above, a pesticide screening test that scanned for over 600 pesticides was completed for samples from the Menindee region. All samples came back negative for pesticide detection.

Metals

Metals were unable to be reported on for this round due to a laboratory processing error. Future monitoring and reporting will include metals.

References

ANZG (2018), Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia. Available at www.waterquality.gov.au/anz-guidelines

Basin Plan (2012), Schedule 11, Water Act 2007, Murray-Darling Basin Authority, Commonwealth of Australia

The Department of Planning and Environment (DPE) collected eight water samples on 25 and 26 July 2023 at Menindee along the Darling-Barka River.

Samples were checked for pesticides, excess nitrogen and phosphorus, ammonia, algae and algal toxins. Metals were unable to be reported on for this round due to a laboratory error.

Routine sampling for this round was interrupted by road closures due to inclement weather. As a result, the additional twelve samples usually collected from the Great Darling Anabranch and lower Darling-Barka River were not able to be collected.

Sample locations

On 25 July 2023, eight samples were collected from the Menindee Weir Pools in the Darling-Barka River. The correlating sample identifications are given in brackets for reference to the full laboratory report data.

• Sample 1 (B1) – Lake Wetherell upstream of the Main Weir
• Sample 2 (B2) – Outlet of Lake Pamamaroo into Darling River
• Sample 3 (E1) – Upper weir pool
• Sample 4 (E2) – Mid weir pool
• Sample 5 (E3) – Menindee town
• Sample 6 (E4) – Downstream Menindee town
• Sample 7 (E5) – Lower weir pool downstream Lake Menindee inflow
• Sample 8 (B3) – Outlet of Lake Menindee into Darling-Barka River

More sampling

The DPE are conducting regular water quality monitoring on the Darling-Barka River from upstream of Menindee to Pooncarie as well as the Great Darling Anabranch. The test results from these samples will also be published on this website.

In-field measurements

At the time of sampling, the DPE collected in-field measurements for pH, dissolved oxygen, conductivity, temperature and turbidity.

All parameters were within the expected ranges.

Nitrogen, phosphorus and ammonia

Sample results show that total nitrogen and total phosphorous are higher than the acceptable levels given for lowland river ecosystems in NSW (ANZG 2018, which are in agreement with the regionally specific set of guideline values for the Murray-Darling outlined in the Basin Plan 2012). Total nitrogen was detected at up to two times higher than the guideline value while total phosphorous was detected at up to four times higher, with the exception of Sample 8 which was seven times higher.  Algal blooms are possible if these nutrients remain elevated.

Bacteria convert nitrogen compounds such as ammonia into nitrite and nitrate. These compounds can harm aquatic organisms. Ammonia was well below the Australian and New Zealand water quality guidelines for toxicity. While the levels would not be expected to be harmful to fish, the ammonia could promote growth in algae and macrophytes. The ammonia is likely to be from river sources including rotting fish and flood organic matter rather than diffuse inputs from surrounding land.

Algae and algal toxins

There were positive detections in all samples for blue-green algae. However, only the blue-green algae detections found in samples 5 and 6 were considered potentially toxic. The algal toxin Cylindrospermopsin was not detected in any samples from this region.

• See WaterNSW for information about current alerts

Pesticides

As noted above, a pesticide screening test that scanned for over 600 pesticides was completed. All samples came back negative for pesticide detection.

References

ANZG (2018), Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia. Available at www.waterquality.gov.au/anz-guidelines

Basin Plan (2012), Schedule 11, Water Act 2007, Murray-Darling Basin Authority, Commonwealth of Australia

The Department of Planning and Environment (DPE) and the NSW Environment Protection Authority (EPA) collected eight water samples on 27 June 2023 at Menindee along the Darling-Barka River.

Samples were checked for pesticides, excess nitrogen and phosphorus, ammonia, metals, algae and algal toxins.

Routine sampling for this round was interrupted by road closures due to inclement weather. As a result, the additional twelve samples usually collected from the Great Darling Anabranch and lower Darling-Barka River were not able to be collected.

Sample locations

On 27 June 2023, eight samples were collected from the Menindee Weir Pools in the Darling-Barka River. The correlating sample identifications are given in brackets for reference to the full laboratory report data.

• Sample 1 (B1) – Lake Wetherell upstream of the Main Weir
• Sample 2 (B2) – Outlet of Lake Pamamaroo into Darling River
• Sample 3 (E1) – Upper weir pool
• Sample 4 (E2) – Mid weir pool
• Sample 5 (E3) – Menindee town
• Sample 6 (E4) – Downstream Menindee town
• Sample 7 (E5) – Lower weir pool downstream Lake Menindee inflow
• Sample 8 (B3) – Outlet of Lake Menindee into Darling-Barka River

More sampling

The DPE and EPA are conducting regular water quality monitoring on the Darling-Barka River from upstream of Menindee to Pooncarie as well as the Great Darling Anabranch. The test results from these samples will also be published on this website.

In-field measurements

At the time of sampling, the EPA collected in-field measurements for pH, dissolved oxygen, conductivity, temperature and turbidity.

All parameters were within the expected ranges.

Nitrogen, phosphorus and ammonia

Sample results show that total nitrogen and total phosphorous are higher than the acceptable levels given for lowland river ecosystems in NSW (ANZG 2018, which are in agreement with the regionally specific set of guideline values for the Murray-Darling outlined in the Basin Plan 2012). Total nitrogen was detected at up to three times higher than the guideline value while total phosphorous was detected at up to eight times higher.  Algal blooms are possible if these nutrients remain elevated.

Bacteria convert nitrogen compounds such as ammonia into nitrite and nitrate. These compounds can harm aquatic organisms. Ammonia was well below the Australian and New Zealand water quality guidelines for toxicity. While the levels would not be expected to be harmful to fish, the ammonia could promote growth in algae and macrophytes. The ammonia is likely to be from river sources including rotting fish and flood organic matter rather than diffuse inputs from surrounding land.

Algae and algal toxins

There were positive detections in all samples for blue-green algae. However, only the blue-green algae detections found in sample 2, 3 and 6 were considered potentially toxic. The algal toxin Cylindrospermopsin was not detected in any samples from this region.

The algae levels detected fall within the ‘amber’ alert levels. An ‘amber alert’ is in place at Menindee and further downstream, as of 25 July 2023.

Pesticides

As noted above, a pesticide screening test that scanned for over 600 pesticides was completed for all samples. All samples came back negative for pesticide detection.

Metals

Many metals are vital for humans and animals to stay healthy and only pose a risk if they are found at high levels in the environment. Concentrations of key metals found in water are below.

Total metals have been compared to recreational water quality guidelines and dissolved metals have been compared to ecological water quality guidelines as per the National Health and Medical Research Council (NHMRC) recreational and Australian and New Zealand Water Quality (ANZG) guidelines, respectively.

Total metals provide a more conservative estimate of exposure from recreational use whereas dissolved metals are used for ecological assessments as this is the bioavailable fraction of the metal (the part that is toxic to organisms).

²NHMRC (2008) Guidelines for managing risks in recreational waters (10 x drinking water guideline value, Table 9.3)

³ANZG (2018). Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia.

References

ANZG (2018), Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia. Available at www.waterquality.gov.au/anz-guidelines

Basin Plan (2012), Schedule 11, Water Act 2007, Murray-Darling Basin Authority, Commonwealth of Australia

NHMRC (2008), Guidelines for managing risks in recreational waters, Australian Government National Health and Medical Research Council

The Department of Planning and Environment (DPE) and the NSW Environment Protection Authority (EPA) collected nineteen water samples between 20 to 22 June 2023 at Menindee along the Darling-Barka River, downstream along the lower Darling-Barka River, and along the Great Darling Anabranch.

Samples were checked for pesticides, excess nitrogen and phosphorus, ammonia, metals, algae and algal toxins.

One of the samples usually collected from the lower Darling-Barka region was unable to be sampled on this occasion, due to accessibility issues following heavy rain.

Sample locations

Water was sampled between 20 to 22 June 2023 from nineteen locations on the Darling-Barka River at Menindee, downstream along the lower Darling-Barka River, and along the Great Darling Anabranch.

On 20 June 2023, eight samples were collected from the Menindee Weir Pools in the Darling-Barka River. The correlating sample identifications are given in brackets for reference to the full laboratory report data.

• Sample 1 (B1) – Lake Wetherell upstream of the Main Weir
• Sample 2 (B2) – Outlet of Lake Pamamaroo into Darling River
• Sample 3 (E1) – Upper weir pool
• Sample 4 (E2) – Mid weir pool
• Sample 5 (E3) – Menindee town
• Sample 6 (E4) – Downstream Menindee town
• Sample 7 (E5) – Lower weir pool downstream Lake Menindee inflow
• Sample 8 (B3) – Outlet of Lake Menindee into Darling-Barka River

On 21 June 2023, four samples were collected from the Great Darling Anabranch region and four samples from the Lower Darling-Barka River between Weir 32 and Pooncarie.

• Sample 9 (B4) – Lake Cawndilla outlet into the anabranch of Darling River
• Sample 10 (E6) – Redbank Creek upstream of Cawndilla Channel confluence
• Sample 11 (E6.5) – Tandou Creek at Tandou Woolshed Rd (incorporating inflows from Kangaroo Lake)
• Sample 12 (E7) – Tandou Creek at Packers Crossing (incorporating inflows from Packers Lake)
• Sample 13 (E8) – Kinchega National Park upper
• Sample 14 (E9) – Kinchega National Park mid (incorporating inflows from Emu Lake)
• Sample 15 (E10) – Kinchega National Park lower (upstream of Anabranch offtake)
• Sample 16 (E11) – Bindara Station reach

On 22 June 2023, three samples were collected from the Lower Darling-Barka River between Weir 32 and Pooncarie.

• Sample 17 (E12) – Karoola Station reach
• Sample 19 (E14) – Mullingar Station reach
• Sample 20 (E15) – Old wharf at Pooncarie

Sample 18 (E13) “Coona Point reach” was unable to be sampled on this occasion, due to accessibility issues following heavy rain.

More sampling

The DPE and EPA are conducting regular water quality monitoring on the Darling-Barka River from upstream of Menindee to Pooncarie as well as the Great Darling Anabranch. The test results from these samples will also be published on this website.

In-field measurements

At the time of sampling, the EPA collected in-field measurements for pH, dissolved oxygen, conductivity, temperature and turbidity.

pH was outside the guideline value for all samples in the Great Darling Anabranch region. 

All other parameters were within the expected ranges.

Nitrogen, phosphorus and ammonia

Sample results show that total nitrogen and total phosphorous are higher than the acceptable levels given for lowland river ecosystems in NSW (ANZG 2018, which are in agreement with the regionally specific set of guideline values for the Murray-Darling outlined in the Basin Plan 2012). Total nitrogen was detected at up to four times higher than the guideline value while total phosphorous was detected at up to seven times higher.  Algal blooms are possible if these nutrients remain elevated.

Bacteria convert nitrogen compounds such as ammonia into nitrite and nitrate. These compounds can harm aquatic organisms. Ammonia was well below the Australian and New Zealand water quality guidelines for toxicity. While the levels would not be expected to be harmful to fish, the ammonia could promote growth in algae and macrophytes. The ammonia is likely to be from river sources including rotting fish and flood organic matter rather than diffuse inputs from surrounding land.

Algae and algal toxins

There were positive detections in all samples for blue-green algae. However, only the blue-green algae detections found in samples 1, 2, 3, 9 to 12, 14 to 17, 19 and 20 were considered potentially toxic. The algal toxin Cylindrospermopsin was detected in samples 10 to 12, 14 to 17, 19 and 20.

The algae levels detected fall within the ‘amber’ to ‘red’ alert levels. A ‘red alert’ is in place along parts of the lower Darling-Barka River. An ‘amber alert’ is in place along the Great Darling Anabranch and along the Darling-Barka River, at Menindee and further downstream, as of 31 July 2023.

Pesticides

As noted above, a pesticide screening test that scanned for over 600 pesticides was completed for samples from all three regions. All samples came back negative for pesticide detection.

Metals

Many metals are vital for humans and animals to stay healthy and only pose a risk if they are found at high levels in the environment. Concentrations of key metals found in water are below.

Total metals have been compared to recreational water quality guidelines and dissolved metals have been compared to ecological water quality guidelines as per the National Health and Medical Research Council (NHMRC) recreational and Australian and New Zealand Water Quality (ANZG) guidelines, respectively.

Total metals provide a more conservative estimate of exposure from recreational use whereas dissolved metals are used for ecological assessments as this is the bioavailable fraction of the metal (the part that is toxic to organisms).

²NHMRC (2008) Guidelines for managing risks in recreational waters (10 x drinking water guideline value, Table 9.3)

²NHMRC (2008) Guidelines for managing risks in recreational waters (10 x drinking water guideline value, Table 9.3)

²NHMRC (2008) Guidelines for managing risks in recreational waters (10 x drinking water guideline value, Table 9.3)

³ANZG (2018). Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia.

³ANZG (2018). Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia.

³ANZG (2018). Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia.

References

ANZG (2018), Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia. Available at www.waterquality.gov.au/anz-guidelines

Basin Plan (2012), Schedule 11, Water Act 2007, Murray-Darling Basin Authority, Commonwealth of Australia

NHMRC (2008), Guidelines for managing risks in recreational waters, Australian Government National Health and Medical Research Council

The Department of Planning and Environment (DPE) and the NSW Environment Protection Authority (EPA) collected eighteen water samples between 13 to 15 June 2023 at Menindee along the Darling-Barka River, downstream along the lower Darling-Barka River, and along the Great Darling Anabranch.

Samples were checked for pesticides, excess nitrogen and phosphorus, ammonia, metals, algae and algal toxins.

Two of the samples usually collected from the lower Darling-Barka region were unable to be sampled on this occasion, due to accessibility issues following heavy rain.

Sample locations

Water was sampled between 13 to 15 June 2023 from eighteen locations on the Darling-Barka River at Menindee, downstream along the lower Darling-Barka River, and along the Great Darling Anabranch.

On 13 June 2023, eight samples were collected from the Menindee Weir Pools in the Darling-Barka River. The correlating sample identifications are given in brackets for reference to the full laboratory report data.

• Sample 1 (B1) – Lake Wetherell upstream of the Main Weir
• Sample 2 (B2) – Outlet of Lake Pamamaroo into Darling River
• Sample 3 (E1) – Upper weir pool
• Sample 4 (E2) – Mid weir pool
• Sample 5 (E3) – Menindee town
• Sample 6 (E4) – Downstream Menindee town
• Sample 7 (E5) – Lower weir pool downstream Lake Menindee inflow
• Sample 8 (B3) – Outlet of Lake Menindee into Darling-Barka River

On 14 June 2023, four samples were collected from the Great Darling Anabranch region and three samples from the Lower Darling-Barka River between Weir 32 and Pooncarie.

• Sample 9 (B4) – Lake Cawndilla outlet into the anabranch of Darling River
• Sample 10 (E6) – Redbank Creek upstream of Cawndilla Channel confluence
• Sample 11 (E6.5) – Tandou Creek at Tandou Woolshed Rd (incorporating inflows from Kangaroo Lake)
• Sample 12 (E7) – Tandou Creek at Packers Crossing (incorporating inflows from Packers Lake)
• Sample 13 (E8) – Kinchega National Park upper
• Sample 14 (E9) – Kinchega National Park mid (incorporating inflows from Emu Lake)
• Sample 15 (E10) – Kinchega National Park lower (upstream of Anabranch offtake)

On 15 June 2023, three samples were collected from the Lower Darling-Barka River between Weir 32 and Pooncarie.

• Sample 17 (E12) – Karoola Station reach
• Sample 19 (E14) – Mullingar Station reach
• Sample 20 (E15) – Old wharf at Pooncarie

Sample 16 (E11) “Bindara Station reach” and Sample 18 (E13) “Coona Point reach” were unable to be sampled on this occasion, due to accessibility issues following heavy rain.

More sampling

The DPE and EPA are conducting regular water quality monitoring on the Darling-Barka River from upstream of Menindee to Pooncarie as well as the Great Darling Anabranch. The test results from these samples will also be published on this website.

In-field measurements

At the time of sampling, the EPA collected in-field measurements for pH, dissolved oxygen, conductivity, temperature and turbidity.

pH was outside the guideline value for some samples in the Great Darling Anabranch region. 

Dissolved oxygen in a few samples around Menindee town (samples 5 and 6) has dropped to levels which may begin to stress fish if they remain low for prolonged periods.

All other parameters were within the expected ranges.

Nitrogen, phosphorus and ammonia

Sample results show that total nitrogen and total phosphorous are higher than the acceptable levels given for lowland river ecosystems in NSW (ANZG 2018, which are in agreement with the regionally specific set of guideline values for the Murray-Darling outlined in the Basin Plan 2012). Total nitrogen was detected at up to eight times higher than the guideline value while total phosphorous was detected at up to nine times higher.  Algal blooms are possible if these nutrients remain elevated.

Bacteria convert nitrogen compounds such as ammonia into nitrite and nitrate. These compounds can harm aquatic organisms. Ammonia was well below the Australian and New Zealand water quality guidelines for toxicity. While the levels would not be expected to be harmful to fish, the ammonia could promote growth in algae and macrophytes. The ammonia is likely to be from river sources including rotting fish and flood organic matter rather than diffuse inputs from surrounding land.

Algae and algal toxins

There were positive detections in all samples for blue-green algae. However, only the blue-green algae detections found in samples 2, 3, 9 to 12, 14, 15, 17, 19 and 20. were considered potentially toxic. The algal toxin Cylindrospermopsin was detected in samples 10, 11, 12, 14, 15, 17, 19 and 20.

The algae levels detected fall within the ‘amber’ to ‘red’ alert levels. A ‘red alert’ is in place along parts of the lower Darling-Barka River. An ‘amber alert’ is in place along the Great Darling Anabranch and along the Darling-Barka River, at Menindee and further downstream, as of 25 July 2023.

Pesticides

As noted above, a pesticide screening test that scanned for over 600 pesticides was completed for samples from all three regions. All samples came back negative for pesticide detection.

Metals

Many metals are vital for humans and animals to stay healthy and only pose a risk if they are found at high levels in the environment. Concentrations of key metals found in water are below.

Total metals have been compared to recreational water quality guidelines and dissolved metals have been compared to ecological water quality guidelines as per the National Health and Medical Research Council (NHMRC) recreational and Australian and New Zealand Water Quality (ANZG) guidelines, respectively.

Total metals provide a more conservative estimate of exposure from recreational use whereas dissolved metals are used for ecological assessments as this is the bioavailable fraction of the metal (the part that is toxic to organisms).

²NHMRC (2008) Guidelines for managing risks in recreational waters (10 x drinking water guideline value, Table 9.3)

²NHMRC (2008) Guidelines for managing risks in recreational waters (10 x drinking water guideline value, Table 9.3)

²NHMRC (2008) Guidelines for managing risks in recreational waters (10 x drinking water guideline value, Table 9.3)

³ANZG (2018). Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia.

³ANZG (2018). Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia.

³ANZG (2018). Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia.

References

ANZG (2018), Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia. Available at www.waterquality.gov.au/anz-guidelines

Basin Plan (2012), Schedule 11, Water Act 2007, Murray-Darling Basin Authority, Commonwealth of Australia

NHMRC (2008), Guidelines for managing risks in recreational waters, Australian Government National Health and Medical Research Council

The Department of Planning and Environment (DPE) and the NSW Environment Protection Authority (EPA) collected eight water samples on 6 June 2023 at Menindee along the Darling-Barka River, downstream along the lower Darling-Barka River, and along the Great Darling Anabranch.

Samples were checked for pesticides, excess nitrogen and phosphorus, ammonia, metals, algae and algal toxins.

Routine sampling for this round was interrupted by road closures due to inclement weather. As a result, the additional twelve samples usually collected as part of the round from the Great Darling Anabranch and lower Darling-Barka River were not able to be collected.

Sample locations

On 6 June 2023, eight samples were collected from the Menindee Weir Pools in the Darling-Barka River. The correlating sample identifications are given in brackets for reference to the full laboratory report data.

• Sample 1 (B1) – Lake Wetherell upstream of the Main Weir
• Sample 2 (B2) – Outlet of Lake Pamamaroo into Darling River
• Sample 3 (E1) – Upper weir pool
• Sample 4 (E2) – Mid weir pool
• Sample 5 (E3) – Menindee town
• Sample 6 (E4) – Downstream Menindee town
• Sample 7 (E5) – Lower weir pool downstream Lake Menindee inflow
• Sample 8 (B3) – Outlet of Lake Menindee into Darling-Barka River