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Murray–Darling Basin: Supporting information

  • Dry conditions contributed to low runoff and streamflow across the region.
  • End-of-year storage volume increased to 40% full due to high rainfall in February–April 2020.
  • 62% of the water accessible for use was taken, primarily for irrigation and agricultural purposes.

Schematic representation of the Murray–Darling Basin region. In 2019–20, runoff was 43% less than average. Storage volumes at 30 June 2020 were 40% full, higher than the previous year. 65% of the total surface water accessible for consumptive use (6,920 GL) was taken. 56% of the total groundwater accessible for consumptive use (3,015 GL) was taken.

For further information on the region's water accounting statements scroll down this page or click on the links below:

 

Water assets

Lake Eildon, Murray–Darling Basin region (Bureau of Meteorology © Paul Feikema)

 

  • Water asset volumes in the region at 30 June 2020 were 14,724 GL, around three quarters of which are surface water assets.

 

Storages

Bar graph of annual storage volume in the Murray–Darling Basin region at 30 June for the years 2010–2020. Accessible storage plus dead storage is plotted against the storage capacity to show percentage full at 30 June each year. Storages at 30 June 2020 were 40% full, higher than the previous year. Since 2010, the highest end-of-year storage volume was in 2012 when storages were 92% full, the lowest was in 2019 when storages were 32% full.
Figure S1 Total storage volume in the region at 30 June 2020 compared with the previous 10 years

 

  • Storage volumes increased from 32% full at 30 June 2019 to 40% full at 30 June 2020, the first annual increase in storage in three years.

 

Map of Murray–Darling Basin region showing the status of each storage at 30 June 2020. The storages are colour coded into nine categories of volume as a proportion of capacity. Most of the storages in the region's northeast are less than 20% full. Most of the storages in the southeast are over 30% full, including the major storages of Hume, Eildon, and Dartmouth (which was over 50% full). An inset line graph shows the time series of percentage-full storage volume between 1 July 2013–30 June 2020. Murray–Darling Basin storages at 30 June 2020 were 40% full, more than last year.
Figure S2 Percentage-full volume on 30 June 2020 for each storage and total storage volume from 2013–2020 (inset)

 

  • In early February 2020, storage levels had dropped to 27% full, the lowest level since April 2010.
  • Storage volumes increased from February 2020 for the remainder of the 2019–20 year following higher rainfall across the region during February–April 2020.
  • Percentage full volumes in major storages in the northern part of the region were generally lower than those in the southern part; many storages in the region's north were still less than 20% full at 30 June 2020.
  • Despite the overall increase in storage, much of the Basin has experienced prolonged dry conditions and by the end of June 2020 significant follow-up rainfall was still needed to replenish these water storages.
  • More detailed information on the individual storages within the region is available on the Bureau of Meteorology's Water Storage website.

 

Rivers, lakes and wetlands, and other assets

  • The volume of water in rivers at 30 June 2020 was below average, similar to last year, reflecting the very dry conditions across the region over the last two years.
  • The volume of water in the region's lakes and wetlands generally changes little from year to year.

 

Groundwater assets

Map of groundwater sustainable diversion limits in the Murray–Darling Basin region. The Goulburn–Murray sustainable diversion limit area has a groundwater asset volume of more than 400,000 ML. South Australian Murray Region, Wimmera–Mallee, Murrumbidgee Alluvium, Lachlan Alluvium, Western Porous Rock, Namoi Alluvium, and Condamine–Balonne areas have groundwater asset volumes of more than 200,000 ML. Murray Alluvium, Eastern Porous Rock, and Warrego–Paroo–Nebine areas have groundwater asset volumes of more than 100,000 ML. Eastern Mount Lofty Ranges, New South Wales Great Artesian Basin Shallow, Macquarie–Castlereagh Alluvium, New England Fractured Rock and Northern Basalts, Queensland Border Rivers–Moonie, and New South Wales Border Rivers Alluvium have groundwater asset volumes of more than 50,000 ML. Darling Alluvium, Lachlan and South Western Fractured Rock, Australian Capital Territory, and Gwydir Alluvium areas have groundwater asset volumes less than 50,000 ML.
Figure S3 Groundwater sustainable diversion limits in the Murray-Darling Basin region

 

  • The groundwater asset volume for the region represents sustainable diversion limit volumes as provided by the Murray–Darling Basin Authority.
  • The groundwater asset volume at the end of the year was the same as the previous year, reflecting no change to the region's sustainable diversion limits.

 

Water liabilities

Agricultural land use, Murray–Darling Basin region (Alison Pouliot © 2010)

 

  • Water liabilities in the Murray–Darling Basin region refer to the volume of allocation remaining on licence entitlements at the end of the 2019–20 year.

 

Table S1 Volume of surface water allocation remaining at 30 June 2020
DescriptionIndividual users (ML)Urban system (ML)Environmental purposes (ML)
 Opening balance at 1 July 20191,616,8170528,601
add Allocation3,433,054578,4291,767,856
less Allocated diversion3,122,501443,7641,975,114
less Adjustment and forfeiture8,426134,665(255,451)
 Closing balance at 30 June 20201,918,9440576,794

 

Table S2 Volume of groundwater allocation remaining at 30 June 2020
DescriptionIndividual users (ML)Urban system (ML)Salinity and water table management (ML)Environmental purposes (ML)
 Opening balance at 1 July 20191,248,9960012,937
add Allocation2,036,99280,82539,03191,285
less Allocated extraction1,427,97332,35114,0480
less Adjustment and forfeiture825,10848,47424,98391,285
 Closing balance at 30 June 20201,032,9070012,937

 

  • Water supply licences for individual users and environmental purposes have carryover provisions, which means a portion of water allocation that has not been abstracted at the end of the water year can be carried over into the next water year.
  • There are no carryover provisions for urban system supply, and salinity and water table management licences. The portion of water allocation that has not been abstracted at the end of a water year is forfeited and the allocation remaining at the end of the year is 0 ML.
  • A more detailed description of water allocations and associated water rights in the Murray–Darling Basin region is given in the Water use section below.

 

Water flows

McIntyre River near Goondiwindi, Murray–Darling Basin region (MDBA © Arthur Mostead)

 

Figure S4 Water inflows and outflows for the region's water stores during the 2019–20 year

 

  • Total surface water flows into the region's storages was 17,054 GL. The key item contributing to surface water inflows was runoff, which made up three quarters of the total surface water inflows.
  • For the third consecutive year, runoff was much lower than average (based on modelled data from 1971–2020) due to the poor rainfall across the region.
  • Outflow to sea is typically one of the larger flows but in 2019–20 it only made up 10% of the total surface water outflows. Outflow was well below average due to the dry conditions and low runoff across the region.
  • Net water taken from surface water and groundwater resources for consumptive use (not including water diverted to the environment) was 6,200 GL, more than 40% of the total outflow (see Water use section below).

 

Water availability

Bar graph of annual surface water availability in the Murray–Darling Basin region for the years 2010–2020. Accessible storage at 1 July plus estimated inflows during the year is plotted against the mean water availability (based on 19701–2020 data). Surface water available during 2019–20 was well below average, similar to the previous year. Surface water availability has been below average for 6 of the last 7 years. Water availability was well above average during 2010–11 and 2011–12.
Figure S5 Annual surface water available in the Murray–Darling Basin region, 2010–11 to 2019–20

 

  • Physical surface water availability is calculated as the sum of accessible storage at the start of the year (see Water assets) and estimated inflows into storages and rivers during the year (see Figure S4).
  • Surface water availability in the Murray–Darling Basin region in 2019–20 was well below average.
  • On average, runoff contributes almost 90% of the total inflows into the region during the year. Very low runoff over the last three years has contributed to below-average water availability in the Murray–Darling Basin region since 2017–18.
  • Water accessible for use and actual water taken are both influenced by the physical water availability. These are discussed in more detail in the Water use section below.

 

Water use

Wheat harvesting, Murray–Darling Basin region (MDBA © Arthur Mostead)

 

Figure S6 Water taken during the 2019–20 year in the region's water resource plan areas

 

  • Total net surface water taken in the region was 5,978 GL. This is the volume of surface water diverted after return flows to rivers and storages are deducted.
  • 67% of the diversions were for individual users, 7% were supplied to the urban system, and 1% was for individual users under a basic right.
  • 25% of the diversions were for environmental purposes, mainly from the SA River Murray Water Resource Plan Area.
  • Total groundwater taken in the region was 1,701 GL.
  • 84% of the extraction was for individual users and 13% was for individual users under a basic right.
  • Around 2% of the extraction was for the urban system while 1% was extracted for salinity and water table management.
  • No groundwater extractions were made for environmental purposes during the year.

 

Bar graph of annual accessible surface water and diversion for different users in the Murray–Darling Basin region from 2011–12 to 2019–20. Accessible surface water is associated with consumptive use (which includes individual users, the urban system, and water taken under basic rights) and the environment. In 2019–20, accessible surface water for consumptive use was lower than previous years. 65% of the accessible water was taken. Accessible water for the environment was higher than the previous year. 54% of the accessible water was taken.
Figure S7 Accessible surface water and diversions in the Murray–Darling Basin region for the years ending 30 June, from 2012–2020

 

  • Accessible water is the volume of water that is lawfully accessible for consumptive use. It is based on the volume of carryover of water entitlements from the previous year and announced allocations during the year.
  • 65% of the accessible surface water was taken (4,499 GL). Most of the surface water diverted was for irrigation and agricultural purposes.
  • Surface water accessible for consumptive use, as well as the actual water taken, was lower than the previous few years due to the continued dry conditions decreasing water availability, particularly during the latter part of 2019 (see Figure S5).
  • The amount of water lawfully accessible for environmental use is based on the volume of carryover of water entitlements from the previous year and announced allocations during the year, and is shown here for comparative purposes.
  • The volume of water diverted for environmental use (1,479 GL) was 25% higher than the previous year, which was influenced by the improved rainfall conditions during the early part of 2020.

 

Bar graph of annual accessible groundwater and extraction for different users in the Murray–Darling Basin region from 2011–12 to 2019–20. Accessible groundwater is associated with consumptive use (which includes individual users, the urban system, and water taken under basic rights) and the environment. In 2019–20, accessible groundwater for consumptive use was similar to the previous few years. 56% of the accessible water was taken. Accessible water for the environment was higher than the previous year. 0% of the accessible water was taken.
Figure S8 Accessible groundwater and extractions in the Murray–Darling Basin region for the years ending 30 June, from 2012–2020

 

  • 56% of the accessible groundwater was taken (1,701 GL). Most of the groundwater extracted was for irrigation supply.
  • Groundwater accessible for consumptive use was similar to the previous few years. Actual water taken was less than the previous year and similar to that taken in 2017–18.
  • The amount of water lawfully accessible for environmental use, which is based on the volume of carryover of water entitlements from the previous year and announced allocations during the year, is less than 2% of the water accessible for consumptive use.
  • There were no groundwater extractions for environmental purposes, similar to the previous few years.

 

Water restrictions

Deniliquin bowling greens, Murray–Darling Basin region (MDBA © Brayden Dykes)

 

  • Information on restrictions related to available water for New South Wales sustainable diversion limit resource units is available on the NSW Department of Industry website.
  • Information on restrictions on allocations for high- and low-reliability water shares (non-urban use) in Victorian sustainable diversion limit resource units is available in the monthly water report from the Victorian Department of Environment, Land, Water and Planning.
  • More information on current restrictions is available on the Bureau's Water Restrictions website.

 

Water market activity

Black Swans at Steamer Plain, Murray–Darling Basin region (MDBA © Keith Ward)

 

  • The Murray–Darling Basin accounts for around 90% of Australia's water allocation trade and 60% of Australia's water entitlement trade.
  • In 2019–20, water market turnover in the Murray–Darling Basin was $6.6 billion, more than 50% higher than the previous year. This increase was driven by record entitlement and allocation prices due to low water availability and high demand during the latter half of 2019.
  • Most of the water trade in the region is related to surface water. In 2019–20, 5,717 GL of surface water allocations and 1,235 GL of surface water entitlements were traded. Allocation trade was 8% higher than last year, which was influenced by the improved rainfall conditions across the region in early 2020.
  • In terms of groundwater, 290 GL of allocations and 184 GL of entitlements were traded during the year.
  • More information is available in the Australian Water Markets Report 2019–20 and on the Bureau's Water Information Dashboard.

 

Map of Murray–Darling Basin region showing interstate allocation trades. 698,016 ML of net allocation water was traded from Victoria to South Australia. 88,010 ML of net allocation water was traded from New South Wales to Victoria. 9,369 ML of net allocation water was traded from New South Wales to South Australia. 190 ML of net allocation water was traded from New South Wales to Queensland.
Figure S9 Direction and volume of interstate allocation trades in the Murray–Darling Basin in 2019–20

 

  • South Australia and Queensland were net importers of allocation water, while Victoria and New South Wales were net exporters. A similar trend of net allocation trade to South Australia was observed during the previous five years.
  • The majority of water transferred to South Australia from the other States was for environmental purposes.

 

Cultural and environmental water

Castlereagh River, Murray–Darling Basin region (Bureau of Meteorology © Malcolm Watson)

 

Cultural benefit

  • Cultural water values are considered within the region's water resource plans (see Water management note), generally as part of the environmental water provisions.
  • An important site within the region, Ranch Billabong, has been identified as a priority cultural site for rehabilitation by the Wotjobaluk Traditional Owners and Aboriginal groups. Environmental water delivered to the Ranch Billabong during 2018–19 and 2019–20 has resulted in a drop in salinity levels and increased frog and birdlife.
  • Guttrum Forest, a floodplain along the Murray River, is also an important site within the region that has cultural significance to the Barapa Barapa and Wemba Wamba Traditional Owners. Environmental water delivered to Reed Bed Swamp in Guttrum Forest during 2019–20 resulted in the returning of water birds and improved conditions of the native trees.
  • More information on the water releases to these cultural-significant sites is available on the Victorian Environmental Water Holder website.

 

Environmental benefit

  • Water for the environment in the Murray-Darling Basin region is delivered through two broad environmental water scenarios: planned environmental water and held environmental water.

 

Planned environmental water provisions

  • Planned environmental water provisions are defined in the overarching Basin Plan as well as the individual water management plans throughout the region (see Water management note).
  • In groundwater systems, water provisions to protect environmental values include annual extraction limits, trading rules, extraction restrictions based on local water level responses, and restrictions on water supply works near environmental and cultural sites.
  • In unregulated rivers, water provisions include annual diversion limits and daily access rules to maintain environmental flows and ecological values.
  • In regulated rivers, in addition to annual diversion limits, water provisions include rule-based requirements for active release of environmental flows at given locations on the rivers.

 

Map of the lower lakes near the mouth of the River Murray. The Murray Mouth is in the southwest of the Murray–Darling Basin region within 100 km of Adelaide. Lake Alexandrina and Lake Albert, located south of the town of Murray Bridge along the River Murray, discharge to the Coorong and Murray Mouth.
Figure S10 Lower lakes at the downstream end of the River Murray

 

  • Water levels in the lakes at the downstream end of the Murray–Darling river system are effected by water diversions and planning provisions across the whole region.
  • One key environmental objective in the Basin Plan is to maintain water levels in the lower lakes to ensure sufficient discharge to the Coorong and Murray Mouth, prevent river bank collapse and acidification of wetlands, and provide connection between Lakes Alexandrina and Albert (see the Basin Plan for more detail).

 

Planned environmental water outcomes

  • In 2019–20, over 1,300 GL of environmental surface water was delivered under plan provisions.
  • Planned deliveries were higher than the previous year reflecting the improved rainfall conditions and increased water availability across the region, particularly in the early part of 2020.

 

Line graph of water level in 2019–20 in Lake Alexandrina, station number LKALEX. The level is compared with the required environmental water provisions: a 95% exceedance target (0.4 m AHD) and a 100% exceedance target (0.0 m AHD). Key aspects of the water level graph are described in the text below the figure.
Figure S11 Water level in the lower lakes at the River Murray mouth during 2019–20

 

  • The Basin Plan includes an objective for the lakes at the River Murray mouth to keep water levels above 0.4 m Australian Height Datum (AHD) 95% of the time and above 0.0 mAHD 100% of the time.
  • In 2019–20, the lakes remained above both targets throughout the entire year.

 

Held environmental water provisions

  • Held environmental water refers to licensed water entitlements that are used exclusively for environmental purposes such as wetland watering or provision of environmental river flows.
  • The volume of water lawfully accessible for environmental use in 2019–20 was over 2,800 GL. Around 98% of this was for surface water sources.
  • The Commonwealth Environmental Water Holder (CEWH) held about 60% of these environmental entitlements. The remaining entitlements were held by some Basin states, the Living Murray program, and other smaller governmental programs.

 

Held environmental water outcomes

  • In 2019–20, 1,975 GL of held environmental water was delivered by environmental managers in the Murray–Darling Basin region.
  • Allowing for estimated return flows, net environmental deliveries were 1,286 GL.