Skip to main content
Go to search page

Murray–Darling Basin drought update

 

Our drought update includes the latest rainfall and water quality information from across the Murray–Darling Basin. It is updated fortnightly — this edition was published on 28 July 2020.

Drought update masthead image

The Murray–Darling Basin has been in drought for some time. Drought is a significant issue for the Basin and continues to impact its environment, industries and communities.

This update provides high-level information on the status of the drought in the Basin, with links to more detailed reports and external websites. The update does not replace any state government alerts and updates.

Key updates 

  • Significant rainfall on the east coast falls mostly outside of the Basin
  • Unregulated flows continue through the southern Basin
  • The latest Spotlight explores the climate driver, La Niña

Rainfall and river flows

A deep low-pressure system over the western Tasman Sea brought significant rainfall to parts of the New South Wales and Victorian coast over the first half of the fortnight. This weather extended into Alpine regions of the Murray–Darling Basin, however only light falls were recorded further inland across the central Basin.

Over the week ending 26 July significant falls occurred in some northern New South Wales catchments, with between 50–100 mm recorded in the Macquarie River region. Similar rainfall was experienced in the Border Rivers region.

Rainfall totals for weeks ending 19 and 26 July 2020
Rainfall totals for weeks ending 19 and 26 July 2020. Source: Bureau of Meteorology

Tributary inflows downstream of Hume Dam have resulted in continued elevated flows through the mid and lower Murray. Flows through the Barmah Choke have been managed to keep the level of the River Murray within channel capacity.

Further downstream, flow into South Australia averaged 12,900 megalitres per day as unregulated flows continued. The arrival of unregulated flows to the Lower Lakes has allowed around 65 gigalitres of water to be released into the Coorong. When conditions allow, additional water will be released to target environmental outcomes.

Flow in the Murrumbidgee River receded from 2,400 to 1,400 megalitres per day as upstream rain made its way through the system and into the Murray.

Downstream releases from Menindee Lakes continued at an average of around 240 megalitres per day. There are currently no significant flows forecast for the Darling River upstream of Menindee.

Temperature 

For most of the Basin minimum and maximum temperatures were around average for the week ending 25 July. Areas of southern New South Wales and the Riverland region of South Australia experienced a dip of up to 6 degrees in minimum temperatures, and the eastern ranges saw a slight increase in maximum temperatures, up by 0–2 degrees.

Maximum and minimum temperature anomalies for week ending 25 July.
Maximum and minimum temperature anomalies for week ending 25 July. Source: Bureau of Meteorology

For more information, see the BoM Climate Outlook for July to September.

Water quality

Although the Basin is still in drought, recent rainfall, changing weather conditions and cooler temperatures have eased the number of threats to water quality in the Basin. It is expected that there will be very little change in current conditions over winter, however the MDBA and state authorities will continue to monitor water quality across the Basin. For more information see the water quality page of our website.

New South Wales sites on RED alert for blue-green algae:

  • Copeton Dam (near Inverell)

Victorian sites on HIGH alert for blue-green algae:

  • Lake Eppalock (near Bendigo)
  • Lake Eildon
  • Tullaroop Reservoir (near Maryborough)

Bushfire water quality risks

Risk of rainfall-mobilised contamination in the following regions:

  • Upper Murray
  • Lake Hume
  • Ovens River

Risk of contamination will decrease as catchment vegetation recovers post-bushfires.

More information

Salinity

Except for significant reductions recorded at Goolwa Barrage, Poltalloch, Morgan and Berri, salinity levels recorded in the River Murray system remained consistent with previous reports.

Goolwa Barrage continues to report a figure significantly higher than average. This is typically caused by a combination of low water levels in Lake Alexandrina and ocean tides causing salt water incursion at the barrages.

Consistent below-average levels recorded at Burtundy are due to a lack of long-term data, following a long period of zero flow in the lower Darling River.

Map of salinity levels in the Murray-Darling Basin
Average salinity level (measured in μS/cm) for the week ending 228 July 2020 and the change compared to the average since 1 August 2019

Salinity measurement locations in River Murray system
* The +/- percentage values in the above map represents the % difference between the most recent ‘average weekly reading’ and a previous average reading. It does not show the difference between the current salinity measurement and the previously reported salinity measurement.

Salinity refers to the concentration of salts in water or soil. High salinity can reduce crop yields, affect aquatic ecosystems and vegetation, and damage infrastructure.

Salinity is measured in EC (electrical conductivity) – the unit of measure used across the Basin is generally microSiemens per centimetre (μS/cm). A salinity level below 800 μS/cm is considered low salinity, however, plant and animal tolerances can range significantly with plant levels generally up to an extreme of 5,800 μS/cm (some plants and animals can cope with higher levels of salinity). By comparison, the salinity of seawater varies although 54,000 μS/cm is an approximate value.

Salinity levels are affected by droughts and floods – high flows help to flush salt from the rivers.

More information

Water in Basin storages

Total storage in the southern Basin increased slightly to 51% as rainfall in upstream catchments continues to be captured. The 6% increase recorded at Hume Dam is being driven by a combination of upstream releases from Snowy Hydro at Khancoban, and Dartmouth Dam.

There was very little change to storage levels at Menindee Lakes, which remains at 27% of capacity. This level is expected to decline slightly over the coming weeks, with no significant inflows forecast from the Darling River.

Storages across the northern Basin remained steady, with slight increases recorded at a few dams including Burrendong and Keepit.

Water in Basin storages - updated 22 July 2020
Water in Basin storages - updated 22 July 2020

The Bureau of Meteorology provides regular water reporting summaries for Murray–Darling Basin catchments. For more information visit BoM water reporting summaries.

More information

Spotlight: La Niña watch continues, but what is it?

Australian winter spring mean rainfall deciles averaged for thirteen strong La Niña events.
Australian winter spring mean rainfall deciles averaged for thirteen strong La Niña events. Source: Bureau of Meteorology

The Bureau of Meteorology (BoM) tells us that Australia is on La Niña watch, which means there is a reasonable chance of above average rainfall in the coming months. This is good news for the Murray–Darling Basin which is still experiencing drought conditions in many areas.

With the El Niño–Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) both neutral, the chance of La Niña forming in 2020 is around 50%— twice the average likelihood. But what are these indicators and how do they work?

The term El Niño refers to the extensive warming of the central and eastern tropical Pacific Ocean which leads to a major shift in weather patterns across the Pacific. This occurs every three to eight years and is associated with drier conditions in eastern Australia. ENSO is the term used to describe the oscillation between the El Niño phase and the La Niña, or opposite, phase.

La Niña is associated with cooler than average sea surface temperatures in the central and eastern tropical Pacific Ocean. La Niña events tend to begin in autumn, mature during winter, spring and early summer, then begin to subside in late summer. The greatest impact normally occurs during the winter, spring and early summer period. La Niña events normally last for around a year, however they can be shorter, or much longer. La Niña i snormally associated with higher than average winter, spring and early summer rainfall over much of Australia.

The IOD is another key driver of Australia's climate. Indian Ocean sea surface temperatures (SSTs) can impact rainfall and temperature patterns over Australia. Warmer than average SSTs in the eastern Indian Ocean can cause changes in the tracks of weather systems to Australia's south, and provide more moisture for frontal systems and lows crossing Australia. The IOD is the difference between SSTs of the tropical western and eastern Indian Ocean.

In its latest climate driver update, the BoM tells us that both La Niña and a negative IOD typically increase the chance of above average rainfall across much of Australia during spring.  Here’s hoping.

Support services for farmers and communities

Rural Financial Counselling Service

The Rural Financial Counselling Service (1800 686 175) provides financial counselling services to farmers, including assistance with financial and business options, developing a financial action plan, accessing government assistance schemes, and referring to other service providers.

Australian Government assistance

The Australian Government provides a number of assistance measures to support farm families, farm businesses and rural communities to prepare for, manage through and recover from drought and other hardship.

The Regional Investment Corporation is offering drought loans for farmers to help them prepare for, manage through or recover from drought.​

Assistance in Queensland

The Queensland Government is offering programs to help farm families, farm businesses and farm communities affected by drought.

Assistance in New South Wales

NSW DroughtHub provides a one-stop online destination for information on a vast range of services and support available to primary producers, their families and communities to prepare for and manage drought.

Assistance in Victoria

The Victorian Government supports farmers throughout Victoria to prepare and respond to drought through technical, financial and personal support.

Assistance in South Australia

The South Australian Government provides a number of services and avenues for assistance to support farm families, farm businesses and rural communities prepare for and manage the drought conditions.

Updated: 28 Jul 2020