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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 3 June 2020.

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. This update does not replace any state government alerts and updates.

Key updates 

  • Moderate rainfall across the Basin decreased over the past fortnight
  • Threats to water quality have decreased due to cooler temperatures and higher river flows
  • Southern Basin storage levels continued to increase as inflows from recent heavy rain are captured
  • ‘A likely wet winter’ is the subject of the latest Spotlight

Rainfall and river flows

Early in the last fortnight a frontal system moved across south-eastern Australia, bringing rainfall to most of Victoria and snowfall to Alpine regions. A surface trough stretching through Queensland into New South Wales brought modest rainfall to the northern Basin, with slightly higher falls in the Paroo, Warrego and Gwydir catchments.

Rainfall then receded over the past week, with no rain recorded in most northern catchments and minor to moderate rainfall across the remaining areas, including southern regions of Victoria and South Australia.

Rainfall totals for weeks ending 25 May and 1 June 2020

Rainfall totals for weeks ending 25 May and 1 June 2020. Source: Bureau of Meteorology

Flows in the Bogan River peaked on 23 May following previous rainfall in that catchment. Overall flows in the northern Basin rivers continued to recede from peaks recorded in March, and flow at Bourke is now around 1,100 megalitres per day. According to WaterNSW, Menindee Lakes inflow forecast is now between 565 and 580 gigalitres. With downstream releases taken into account, the total volume held in the lakes is estimated to eventually be around 480 gigalitres.

In the south, flows in the Murray system are mostly being driven by recent rainfall in upper catchments, which have also contributed to increasing levels in major storages. Regulators in the Barmah–Millewa Forest that were opened in May to manage high flows, were progressively closed as the flow rate through the Barmah Choke returned to within channel capacity.

Further downstream, flows to South Australia increased as inflows from upstream catchments travelled through the system. Increased flow across the border was also a result of managing maximum inflows to Lake Victoria.

At the Lower Lakes, water was released into the Coorong through fishways and Tauwitchere barrage. More information on barrage releases is available in the South Australian Department for Environment and Water Weekly River Murray Flow Report.

Temperature 

The approach of winter combined with a cold front to produce below average maximum temperatures to almost the entire Basin through May, excluding a small region near the Queensland border. Minimum temperatures ranged between average in the east, to below average in southern and western catchments.

Temperature deciles for May 2020

Maximum and minimum temperature deciles for May 2020. Source: Bureau of Meteorology

More information

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:

  • Windamere Dam
  • Chifley Dam
  • Pindari Dam
  • Lake Albert (Wagga Wagga)
  • Wyangala Dam – Abercrombie River arm

Victorian sites on HIGH alert for blue-green algae:

  • Lake Eppalock (near Bendigo)
  • National Channel #2 (Torrumbarry Irrigation Area)

Bushfire water quality risks - Upper Murray & Lake Hume:

  • Potential water quality risks to Upper Murray and Lake Hume areas from bushfire contamination, as mobilised by rainfall events exceeding 20–30 mm.

More information

Salinity

Salinity levels throughout the Murray system have not significantly changed when compared to the previous fortnight, with most sites recording levels around the long-term average.

Goolwa Barrage is reporting 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 barrage.

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.

The following map shows the average salinity level (measured in μS/cm) for the week ending 27 May 2020 and the change compared to the average since 1 August 2019.

Map of salinity levels in the Murray-Darling Basin

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 river system

More information

Water in Basin storages

In the northern Basin there were only minor changes (<1%) to many storage levels over the past fortnight, mostly due to a combination of lower inflows and decreasing demand leading into winter. Overall storage levels for the region remain at 17%, which is equal to the previous drought update.

Inflows in the upper catchments of the southern Basin continue to increase storage levels in many key storages—particularly Hume Dam on the Murray River, and Burrinjuck on the Murrumbidgee River. Some of the higher flows through the mid-Murray were diverted into Lake Victoria, increasing the storage level by 17%.

Despite recent rain in the south, and significant rainfall across many Basin catchments so far in 2020, the overall storage level in the Basin remains low, at 35% of capacity.

Water storage levels in the Murray-Darling Basin
Water in Basin storages as reported at 27 May 2020.
The Bureau of Meteorology provides regular water reporting summaries for Murray-Darling Basin catchments. For more information visit http://www.bom.gov.au/water/nrtwreporting/

More information

Spotlight – winter likely to be a wet one

The latest climate outlook from the Bureau of Meteorology (28 May) forecasts a wetter than average winter for most of the Basin, with most catchments showing a 70 to 80 % chance of receiving rainfall above the median between June and August.

Chance of rainfall exceeding median for June to August 2020

Chance of rainfall exceeding median for June to August 2020. Source: Bureau of Meteorology

Most of this rainfall is expected to occur in July/August, while June will be slightly drier than average.

Some catchments (particularly those in the north-west) are forecast to receive less rain (25–100mm, while heavier falls are likely over the Victorian and southern New South Wales ranges, with between 400 and 600 millimetres falling over alpine regions.

Anticipated rainfall would contribute to streamflow in many areas, with hope that south-eastern storages in particular will benefit from likely high flows.

Rainfall totals with 75% chance of occurring from June to August 2020

Rainfall—totals that have a 75% chance of occurring for June to August. Source: Bureau of Meteorology

Above average rainfall will likely be accompanied by warmer than average daytime temperatures around the eastern ranges. Overnight temperatures are very likely to be warmer than average throughout the Basin (more than 80% chance for most regions).

Increasing rainfall and warmer temperatures are being driven by a warmer than average eastern Indian Ocean, linked to a neutral Indian Ocean Dipole and neutral The El Niño–Southern Oscillation (ENSO). The Bureau notes that a La Niña phase is possible by the end of winter, which would bring cooler maximum temperatures and a shift in temperature extremes, among other weather variables.

For more information, see the BoM Climate Outlook video below, or their website:
http://www.bom.gov.au/climate/outlooks/#/overview/summary

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: 03 Jun 2020