Murray–Darling Basin
Physical information
General description
Area: 1,055,600 km2 , which is 14% of mainland Australia (Australian Bureau of Agricultural and Resource Economics and Sciences 2010)
Population: 2,190,000 (Australian Bureau of Statistics [ABS] 2011)
The Murray–Darling Basin (MDB) region is defined by the catchment areas of the Murray and Darling rivers and their many tributaries. The region covers 75% of New South Wales, more than 50% of Victoria, sections of Queensland and South Australia, and all of the Australian Capital Territory as shown in Figures P1and P2 below. It contains:
- 40,000 km of major rivers and approximately 440,000 km of rivers in total
- some 30,000 wetlands, covering an area of around 25,000 km²
- about 60,000 km² of floodplain area, which represents approximately 6% of the Murray–Darling Basin region.
Figure P1 The Murray–Darling Basin region within Australia
Sources: Australian Government Department of the Environment and Geoscience Australia (2010)
As shown in Figure P2, major rivers in the Murray–Darling Basin region include:
- Darling River, which begins in northern New South Wales and with its major tributaries (including the Culgoa, Balonne, and Condamine rivers) flows for 2,740 km southwest to its junction with the River Murray at Wentworth
- River Murray, which forms the border of Victoria and New South Wales, and flows east to west for 2,520 km
- Murrumbidgee River, which flows 1,575 km from southern New South Wales, through the Australian Capital Territory and then westwards to the River Murray
- Lachlan River, which starts in the central highlands of New South Wales and flows 1,339 km southwest to the Murrumbidgee River
- Goulburn River, which flows 654 km from central northern Victoria northwards into the River Murray (Geoscience Australia 2010).
The Murray–Darling Basin region is a complex, interconnected river system rather than a series of separate catchments; however, its diverse climate and landscape and the presence of artificial structures means not all parts of the system are connected to the same extent. For example, rivers such as the Paroo, Lachlan, only rarely and Wimmera will never contribute flows further downstream.
The Murray–Darling Basin region presents a varied landscape, from semi-arid ephemeral river systems in the north to highly regulated river systems in the south fed from the Australian Alps. To the east and south, the highlands of the Great Dividing Range form the limit of the Murray–Darling Basin region, while in the north, west, and southwest the boundaries are much less distinct. The greater proportion of the Murray–Darling Basin region is made up of extensive plains and low undulating areas; most of them are less than 200 m above sea level.
Figure P2 Contextual map of the Murray–Darling Basin region showing the major rivers and towns
Sources: Australian Government Department of the Environment and Geoscience Australia (2010)
Region definition
The Murray–Darling Basin (MDB) region is defined in Section 18A of the Australian Government Water Act 2007 (the Act). It includes all water resources within or beneath the MDB region, but does not include groundwater that forms part of the Great Artesian Basin (GAB). The GAB is not included in the MDB region as it has its own management arrangements and therefore it is specifically excluded under the Act.
The 2014 Account, adopts the geographical boundary definition as specified in S18A of the Act for Murray–Darling Basin region (see Figure P2) except:
- the areas draining into the Snowy Mountains Hydroelectric Scheme storages that are located within the geographical boundaries of the MDB as specified by the Act, and
- the towns of Port Elliot and Middleton in South Australia.
These exclusions align the National Water Account MDB region boundary to the Murray–Darling Basin Authority operational area boundary.
Further, the following elements are not included in the Murray–Darling Basin region 2014 account:
- off-channel water storages, such as landscape catchment storages (also known as farm dams and run-off dams) used to harvest runoff and floodwaters (these constitute water abstracted before it reaches the rivers or water owned by the users)
- urban water systems at utility level and private water supply systems.
Geographical representation of the Murray–Darling Basin region in the 2014 Account
The 2014 Account provides information for the entire Murray–Darling Basin region and also its two segments, the Northern Basin and the Southern Basin (see Figure P3). The Northern Basin and Southern Basin boundaries are largely determined by the physical geography of the Murray–Darling Basin, previous water management boundaries, and the level of hydrological connectivity. The hydrological boundary between the Northern Basin and the Southern Basin is located where the Darling River meets the upstream end of the Menindee Lakes.
The Northern Basin typically has less rainfall, regulation, development, and water use than the Southern Basin. Furthermore, water management in the Northern Basin is characterised by a different rules framework, fewer water storages, and highly variable hydrological connectivity when compared with water management in the Southern Basin.
The Murray–Darling Basin region is divided into 20 surface water water resource plan areas and 22 groundwater water resource plan areas (both numbers include six combined surface water and groundwater water resource plan areas) to provide information in the 2014 Account. Detailed information has been provided in the account, where data was available at sustainable diversion limit (SDL) resource unit level. Details of water resource plan areas and SDL resource units are included under Surface water and Groundwater.
Land use
Major towns and cities within the region
The major population centres of the Murray–Darling Basin region and their population include:
- Canberra–Queanbeyan: 426,000
- Toowoomba: 96,567
- Bendigo: 82,794
- Albury–Wodonga: 82,083
- Wagga Wagga: 46,913
- Shepparton: 42,741
- Tamworth: 36,131
- Orange: 34,992
- Mildura–Buronga: 33,432
- Dubbo: 32,327
- Bathurst: 31,294 (ABS 2011).
Note: The population numbers are related to urban centre / locality.
There are also a number of smaller urban centres throughout the Murray–Darling Basin region such as Griffith, Echuca, Moree, Horsham, Wangaratta, Warwick and Murray Bridge.
Land use activities
The Murray–Darling Basin region is one of the most productive food and fibre regions in Australia. It contains approximately 40% of all Australian farms (by number), which produce rice, cotton, grapes, wool, wheat, hay, fruits, products from sheep and livestock, dairy products, oilseeds, wine, and vegetables for domestic and overseas markets (Murray–Darling Basin Authority [MDBA] 2015i).
The major land use activities in the Murray–Darling Basin region are shown in Table P1. Figure P3 shows the distribution of these land uses within the Murray–Darling Basin region. Land use classifications were derived from Australian Government Department of Agriculture 2014a sources. Land use activities that are major water users in the Murray–Darling Basin region are irrigated agriculture and urban supply.
Land use activity | Area (km2) | Total area of the region (%) |
conservation and natural environments | 101,841 | 10 |
dryland agriculture | 146,740 | 14 |
forestry | 43,109 | 4 |
grazing | 704,889 | 67 |
irrigated agriculture | 28,435 | 3 |
mining | 660 | <1 |
other intensive uses | 6,913 | <1 |
urban | 11,867 | 1 |
water | 11,145 | 1 |
Total | 1,055,599 |
|
Source: Australian Government Department of Agriculture 2014b
Figure P3 Land use in the Murray–Darling Basin region
Significant aquatic ecosystems
The Murray–Darling Basin region contains 17 Ramsar-listed wetlands (Australian Government Department of the Environment 2014c) of international importance, as listed below and also shown in Figure P4.
- Banrock Station Wetland Complex (South Australia)
- Barmah Forest (Victoria)
- Blue Lake Ramsar Site (New South Wales)
- Coorong and Lakes Alexandrina and Albert (South Australia)
- Currawinya Lakes National Park (Queensland)
- Fivebough and Tuckerbil Swamps (New South Wales)
- Ginini Flats Wetland Complex (Australian Capital Territory)
- Gunbower Forest (Victoria)
- Gwydir Wetlands (New South Wales)
- Hattah–Kulkyne Lakes (Victoria)
- Kerang Wetlands (Victoria)
- Lake Albacutya (Victoria)
- Macquarie Marshes (New South Wales)
- Narran Lake Nature Reserve (New South Wales)
- NSW Central Murray State Forests (New South Wales)
- Paroo River Wetlands (New South Wales)
- Riverland (South Australia).
The Murray–Darling Basin region contains a further 30,000 wetlands in total, some of which are listed as nationally important in the Directory of Important Wetlands in Australia (Australian Government Department of the Environment 2014d).
Figure P4 Ramsar wetlands in the Murray–Darling Basin region
There are eight icon sites, which are a collection of important locations along the River Murray, selected for their high ecological value and cultural significance. The focus of The Living Murray program—a joint partnership between the MDBA, Australian Government and Basin State Governments—is to improve the environmental health of these sites through environmental watering (both planning and delivery) and monitoring, to ensure Australian communities can continue to enjoy the River Murray for years to come.
Each site is regionally and nationally significant to Aboriginal and other communities and most are recognised internationally under the Ramsar Convention—an intergovernmental treaty that provides the framework for national action and international cooperation for the conservation and wise use of wetlands and their resources.
Significant Indigenous cultural places and practices
The Murray–Darling river system has been and continues to be of high importance to Aboriginal people, and their history in the Murray–Darling Basin region extends over at least 45,000 years to the present day. There are at least 10,000 known Aboriginal sites in the Murray–Darling Basin, indicating the deep physical, economic, and spiritual dependence of Aboriginal people on its rivers, creeks, lakes, wetlands and other resources. The rivers and flood plains are of particular importance to the traditional cultural beliefs and practices of Aboriginal nations. Today there are over 40 Aboriginal nations in the Murray–Darling Basin (Murray–Darling Basin Authority 2014c).
Archaeological evidence can be found including such things as shell middens, quarries, rock shelters with archaeological deposits (e.g. stone artefacts), open campsites, rock paintings and engravings, axe grinding rocks with their grooves, burial grounds, and the sacred and ceremonial sites. The sites are dated from a range of ages:
- 9,000–13,000 years old: the Kow Swamp burial site in northern Victoria
- at least 20,000 years old: excavations indicating Aboriginal presence at Keniff Cave, at the headwaters of the Darling River
- approximately 40,000 years old: evidence of Aboriginal populations from Lake Mungo and other lakes of the Willandra system. Willandra Lakes area's historical significance was recognised with its World Heritage listing in 1981
- of more recent origin: the many carved and scarred trees from which bark canoes, shields, boomerangs and carrying dishes were cut. These trees can be found along most of the MDB's waterways.
Aboriginal people view themselves as an integral part of the land and river systems and feel a strong responsibility for the health of rivers and wetlands. The rivers have always been of great importance to the Aboriginal people, especially as sources of food. As an example, the fishtraps of the Ngemba in the Barwon River at Brewarrina illustrate how the river serves as a critical source of food. Brewarrina is well known for the 40,000 year old aboriginal fishtraps that are located just below the weir in the Brewarrina township. These traps are constructed from carefully placed rocks in a circular arrangement and are still used today.
Water resources
The water resources in the Murray–Darling Basin region are highly developed particularly in the Southern Basin, as illustrated by the following statistics:
- As a long-term average, 42% of the total surface water runoff to the Murray–Darling Basin region is diverted for consumption or environmental management purposes (Murray–Darling Basin Authority 2013b)
- Most of the surface water consumed in the Murray–Darling Basin region, 10.9 million ML/year on average, is diverted from the watercourse and used for irrigation and urban water supply. In addition, 2.7 million ML/year of runoff is intercepted by local catchment storages and forestry plantations before it reaches the watercourse (Murray–Darling Basin Authority 2011)
- Approximately 1.8 million ML of the Murray–Darling Basin's groundwater resources is consumed each year (Murray–Darling Basin Authority 2014d); however, due to the abundance of surface water resources, a lower volume has been consumed in recent years. The majority of groundwater use is centred on a small number of large alluvial aquifers in New South Wales, Queensland, Victoria, and South Australia where the groundwater is used for agricultural purposes. Elsewhere, there are areas in the Murray–Darling Basin where groundwater is the only reliable source of water for stock and domestic uses.
The Murray–Darling Basin Cap (the Cap) was established in 1995 to limit the volume of surface water that could be diverted in the Murray–Darling Basin region in any year to that based on the 1993–1994 levels of development (Murray–Darling Basin Authority 2012h). The Cap does not place a restriction on groundwater extraction; however, the Basin Plan 2012 (Murray–Darling Basin Authority 2013b) established sustainable diversion limits (SDLs) for both groundwater and surface water within the Murray–Darling Basin region. See Operating rules and constraints within the 'Water rights' section for further information on the Cap.
Surface water
The southern part of the Murray–Darling Basin region is mostly a regulated system with major storages in many rivers. The storages in the three major southern rivers—the Murrumbidgee, Murray, and Goulburn—are used to provide regulated flows downstream as far as the lower lakes in South Australia.
Although there are major storages in the rivers including Border, Gwydir, Namoi and Macquarie, the northern part of the Murray–Darling Basin region consists mostly of unregulated systems. Many of the rivers and streams in the northern Murray–Darling Basin region are ephemeral and fed by seasonal rainfall. Generally, water users in much of the northern Murray–Darling Basin region rely on collecting water during floods and storing it on-farm for later use.
The 2014 Account presents information on the volume for water resource plan areas for surface water in the Murray–Darling Basin region, as shown in Figure P5 (Murray–Darling Basin Authority 2011). Table P2 provides details of 20 water resource plan areas for surface water and 29 sustainable diversion limit (SDL) resource units.
Figure P5 Water Resource Plan areas for surface water within the Murray-Darling Basin region
A Surface water SDL resource units map is available from the MDBA website.
| Segment | Jurisdiction | Water resource plan area | Sustainable diversion limit (SDL) resource unit | River system | ||
Code | Name | Code | Name | |||
| Southern Basin | Australian Capital Territory | SW1 | Australian Capital Territory (surface water) | SS1 | ACT (surface water) | Murrumbidgee, Australian Capital Territory |
| Victoria | SW2 | Victorian Murray | SS2 | Victorian Murray | The Murray, Victoria | |
| SS3 | Kiewa | Kiewa | ||||
| Victoria | SW3 | Northern Victoria | SS4 | Ovens | Ovens | |
| SS5 | Broken | Broken | ||||
| SS6 | Goulburn | Goulburn | ||||
| SS7 | Campaspe | Campaspe | ||||
| SS8 | Loddon | Loddon | ||||
| Victoria | SW4 | Wimmera–Mallee (surface water) | SS9 | Wimmera–Mallee (surface water) | Wimmera–Mallee | |
| South Australia | SW5 | South Australian Murray Region1 | SS10 | SA Non-Prescribed Areas | SA Non-Prescribed Areas, South Australia | |
| South Australia | SW6 | South Australian River Murray | SS11 | SA Murray | The Murray, South Australia | |
| South Australia | SW7 | Eastern Mount Lofty Ranges1 | SS12 | Marne–Saunders | Marne–Saunders | |
| SS13 | Eastern Mount Lofty Ranges | Eastern Mount Lofty Ranges | ||||
| New South Wales | SW 8 | New South Wales Murray and Lower Darling | SS14 | NSW Murray | The Murray, New South Wales | |
| SS18 | Lower Darling | Darling | ||||
| New South Wales | SW9 | Murrumbidgee | SS15 | Murrumbidgee NSW | Murrumbidgee, New South Wales | |
| New South Wales | SW10 | Lachlan | SS16 | Lachlan | Lachlan | |
| Northern Basin | New South Wales | SW11 | Macquarie–Castlereagh | SS20 | Macquarie–Castlereagh | Macquarie–Castlereagh |
| New South Wales | SW12 | Barwon–Darling Watercourse | SS19 | Barwon–Darling Watercourse | Barwon–Darling | |
| New South Wales | SW13 | Intersecting Streams | SS17 | NSW Intersecting Streams | Paroo, Warrego, Culgoa, Bokhara, Narran, and Moonie | |
| New South Wales | SW14 | Namoi | SS21 | Namoi | Namoi | |
| New South Wales | SW15 | Gwydir | SS22 | Gwydir | Gwydir | |
| New South Wales | SW16 | New South Wales Border Rivers | SS23 | NSW Border Rivers | New South Wales Border Rivers | |
| Queensland | SW17 | Queensland Border Rivers1 | SS24 | Queensland Border Rivers | Queensland Border Rivers | |
| Queensland | SW18 | Moonie1 | SS25 | Moonie | Moonie | |
| Queensland | SW19 | Condamine–Balonne1 | SS26 | Condamine–Balonne | Condamine–Balonne | |
| Queensland | SW20 | Warrego–Paroo–Nebine1 | SS27 | Nebine | Nebine | |
| SS28 | Warrego | Warrego | ||||
| SS29 | Paroo | Paroo | ||||
1 Combined surface water and groundwater resource plan areas
Major storages
The total storage capacity (including dead storage) for the 55 major storages (excluding weirs not considered as storages) within the Murray–Darling Basin region for which data are available for the 2014 Account was 23,203,628 ML. A full list of these storages and their individual total storage capacities can be found in the downloadable table under Storages.
Streamflow summary
The 2014 Account includes streamflow summaries at the following gauging stations within the Murray–Darling Basin region:
- The River Murray at Doctors Point (Albury) (Station 409017) represents a regulated reach of the Murray downstream of major regulating storages (within the Southern Basin)
- The Darling River at Bourke (Station 425003) represents the unregulated Northern Basin
- Ovens River at Peechelba (Station 403241) represents a largely unregulated major river in the Southern Basin.
Figure P6 shows mean monthly rainfall and flow volumes for these three gauging stations. The locations of the gauging stations are shown in Figure P7.
Figure P6 Graph of mean monthly flows at selected gauging stations in the Murray, Darling and Ovens rivers; mean monthly rainfall for the region is also shown
Figure P7 Key streamflow gauging station locations along the main rivers within the Murray–Darling Basin region
Information on streamflow patterns, monthly flow volumes and variations for the flows at the stations are available in Streamflow in the 2014 Account 'Water overview' for Murray–Darling Basin.
Water transfers
In a number of locations, water is transferred into or out of the Murray-Darling Basin region, as well as from one catchment to another within the Murray-Darling Basin region (see Figure P8).
Figure P8 Water transfers into, out of, or between catchments within the Murray–Darling Basin region
Transfers into the MDB region are from:
- the Snowy Mountains Hydro-Electric Scheme into the Murrumbidgee and Murray rivers (see Inter-region claim on water for more details)
- the Glenelg catchment to the Wimmera system
- Perseverance, Cressbrook, and Wivenhoe reservoirs (through Cressbrook reservoir, which started in 2010) in the Brisbane valley to Toowoomba in the Condamine–Balonne region.
Transfers out of the MDB region include diversion of water from:
- the South Australian River Murray to supply metropolitan Adelaide and country towns
- the Macquarie River water sources (Fish River Scheme) to the Blue Mountains area in Sydney
- the Goulburn River system via the North–South pipeline for distribution to Melbourne
- water transfers from the Goulburn–Broken region to Ballarat (in the Barwon River basin) via the Goldfields superpipe since May 2008
- water transfers from the Goulburn–Broken region (from Silver and Wallaby creeks, which are tributaries of the Goulburn River, not shown in Figure P7) to the Melbourne urban supply system.
Channels and pipelines in the river system of the Southern Basin allow water to be moved and traded from one catchment to another. For example, the Waranga Western Channel delivers water from the Goulburn River to the Campaspe, Loddon, and Wimmera–Avoca catchments.
Groundwater
The groundwater systems of the Murray-Darling Basin region can be categorised into four distinct hydrogeological types:
- the aquifers in sedimentary deposits of the Murray Basin and the Great Artesian Basin (GAB,) within the low topographic landscapes (including the Lower Murrumbidgee and the South Australian Murray)
- the shallow aquifers of the Darling River Basin overlying the GAB (including the Lower Namoi and Gwydir)
- valley-fill alluvium (including the Mid-Murrumbidgee, Upper Namoi and Upper Lachlan) in the highlands bordering the region
- the local fractured rock aquifers of the Great Dividing Range and other areas where the basement rock outcrops.
While the GAB is a major groundwater resource under the Basin, it is not included in the 2014 Account. The boundaries of the groundwater systems do not align with those of the Murray–Darling Basin, which is defined on the basis of its surface water resources.
The different groundwater systems behave somewhat independently of each other, with only relatively small volumes of groundwater directly flowing from one system to another; however, water from different aquifer systems is transferred across boundaries as surface water base flow. Through this process, a substantial volume of groundwater enters the surface streams in the upper and middle catchments as base flow and then re-enters the groundwater systems further down through seepage from streambeds (Murray–Darling Basin Commission 1998).
The 2014 Account, provides groundwater information on 22 water resource plan areas for groundwater (Murray–Darling Basin Authority 2013b). Detailed information has been provided where data is available at the level of sustainable diversion limit (SDL) resource unit. Figure P9 and tables P3 and P4 provide details of 22 water resource plan areas for groundwater and 81 SDL resource units.
Figure P9 Water resource plan areas for groundwater within the Murray–Darling Basin region
A map of the groundwater SDL resource units is available from the MDBA website.
A map of the deep groundwater SDL resource units is available from the MDBA website.
Jurisdiction | Water resource plan area | Segment of the MDB region | Sustainable diversion limit (SDL) resource unit | ||
Code | Name | Code | Name | ||
| New South Wales | GW7 | Darling Alluvium1 | Northern Basin | GS42 | Upper Darling Alluvium |
| New South Wales | GW11 | Lachlan and South Western Fractured Rock2 | Northern Basin | GS19 | Kanmantoo Fold Belt |
| New South Wales | GW12 | Macquarie–Castlereagh Alluvium | Northern Basin | GS11 | Bell Valley Alluvium |
| GS14 | Castlereagh Alluvium | ||||
| GS15 | Collaburragundry–Talbragar Alluvium | ||||
| GS16 | Cudgegong Alluvium | ||||
| GS26 | Lower Macquarie Alluvium | ||||
| GS45 | Upper Macquarie Alluvium | ||||
| New South Wales | GW13 | New South Wales Great Artesian Basin Shallow | Northern Basin | GS34 | New South Wales Great Artesian Basin Surat Shallow |
| GS35 | New South Wales Great Artesian Basin Warrego Shallow | ||||
| GS36 | New South Wales Great Artesian Basin Central Shallow | ||||
| New South Wales | GW14 | Namoi Alluvium | Northern Basin | GS29 | Lower Namoi Alluvium |
| GS30 | Manilla Alluvium | ||||
| GS40 | Peel Valley Alluvium | ||||
| GS47 | Upper Namoi Alluvium | ||||
| GS48 | Upper Namoi Tributary Alluvium | ||||
| New South Wales | GW15 | Gwydir Alluvium | Northern Basin | GS24 | Lower Gwydir Alluvium |
| GS43 | Upper Gwydir Alluvium | ||||
| New South Wales | GW16 | Eastern Porous Rock | Northern Basin | GS17 | Gunnedah–Oxley Basin |
| GS41 | Sydney Basin | ||||
| New South Wales | GW17 | New England Fractured Rock and Northern Basalts | Northern Basin | GS18 | Inverell Basalt |
| GS22 | Liverpool Ranges Basalt | ||||
| GS37 | New England Fold Belt | ||||
| GS49 | Warrumbungle Basalt | ||||
| New South Wales | GW18 | New South Wales Border Rivers Alluvium | Northern Basin | GS32 | NSW Border Rivers Alluvium |
| GS33 | NSW Border Rivers Tributary Alluvium | ||||
| Queensland | GW19 | Queensland Border Rivers3 | Northern Basin | GS54 | Queensland Border Rivers Alluvium |
| GS55 | Queensland Border Rivers Fractured Rock | ||||
| GS57 | Sediments above the Great Artesian Basin: Border Rivers | ||||
| Queensland | GW20 | Moonie4 | Northern Basin | GS59 | Sediments above the Great Artesian Basin: Moonie |
| GS62 | St George Alluvium: Moonie | ||||
| Queensland | GW21 | Condamine–Balonne5 | Northern Basin | GS53 | Condamine Fractured Rock |
| GS56 | Queensland MDB: deep | ||||
| GS58 | Sediments above the Great Artesian Basin: Condamine–Balonne | ||||
| GS61 | St George Alluvium (deep and shallow) | ||||
| GS64 | Upper Condamine Alluvium (Central Condamine Alluvium and tributaries) | ||||
| GS65 | Upper Condamine Basalts | ||||
| Queensland | GW22 | Warrego–Paroo–Nebine6 | Northern Basin | GS60 | Sediments above the Great Artesian Basin: Warrego–Paroo–Nebine |
| GS63 | St George Alluvium: Warrego–Paroo–Nebine | ||||
| GS66 | Warrego Alluvium | ||||
1-2 Straddles both the Northern Basin and the Southern Basin
3-6 Combined surface water and groundwater resource plan areas
Jurisdiction | Water resource plan area | Segment of the MDB region | Sustainable diversion limit (SDL) resource unit | ||
Code | Name | Code | Name | ||
| ACT | GW1 | Australian Capital Territory (groundwater) | Southern Basin | GS52 | Australian Capital Territory (Groundwater) |
| Victoria | GW2 | Goulburn–Murray | Southern Basin | GS8 | Goulburn–Murray (Shepparton Irrigation Region, Sedimentary Plain, Highlands and deep) |
| Victoria | GW3 | Wimmera–Mallee (groundwater) | Southern Basin | GS9 | Wimmera–Mallee (Sedimentary Plain, Highlands and deep) |
| South Australia | GW4 | South Australian Murray Region1 | Southern Basin | GS3 | Mallee (Pliocene Sands, Murray group Limestone and Renmark group) |
| GS5 | Peake–Roby–Sherlock (confined and unconfined) | ||||
| GS6 | SA Murray | ||||
| GS7 | SA Murray Salt Interception Schemes | ||||
| South Australia | GW5 | Eastern Mount Lofty Ranges2 | Southern Basin | GS1 | Angas Bremer (Quaternary Sediments and Murray Group Limestone) |
| GS2 | Eastern Mount Lofty Ranges | ||||
| GS4 | Marne Saunders (Murray Group Limestone, Renmark Group and Fractured Rock) | ||||
| New South Wales | GW6 | Western Porous Rock | Southern Basin | GS50 | Western Porous Rock |
| New South Wales | GW7 | Darling Alluvium3 | Southern Basin | GS23 | Lower Darling Alluvium |
| New South Wales | GW8 | Murray Alluvium | Southern Basin | GS13 | Billabong Creek Alluvium |
| GS27 | Lower Murray Alluvium (deep[Renmark Group and Calivil Formation]; and shallow [Shepparton Formation]) | ||||
| GS46 | Upper Murray Alluvium | ||||
| GS38 | Oaklands Basin | ||||
| New South Wales | GW9 | Murrumbidgee Alluvium | Southern Basin | GS21 | Lake George Alluvium |
| GS28 | Lower Murrumbidgee Alluvium (deep [Renmark Group and Calivil Formation]; and shallow [Shepparton Formation]) | ||||
| GS31 | Mid–Murrumbidgee Alluvium | ||||
| New South Wales | GW10 | Lachlan Alluvium | Southern Basin | GS12 | Belubula Alluvium |
| GS25 | Lower Lachlan Alluvium | ||||
| GS44 | Upper Lachlan Alluvium | ||||
| New South Wales | GW11 | Lachlan and South Western Fractured Rock4 | Southern Basin | GS10 | Adelaide Fold Belt |
| GS20 | Lachlan Fold Belt | ||||
| GS39 | Orange Basalt | ||||
| GS51 | Young Granite | ||||
1-2 Combined surface water and groundwater resource plan areas
3-4 Straddles both the Northern Basin and the Southern Basin
The sedimentary aquifers within the region cover the main depositional areas of the Murray geological and Darling River basins including upstream reaches of other major rivers such as the Murrumbidgee and the Namoi. The major aquifers within or at the peripheries of the Murray geological basin include the Shepparton, Calivil, Parilla–Loxton Sands, Murray Limestone, and Renmark Group aquifers, and the upland alluvium of the Cowra and Lachlan formations. The important alluvial sediments of the Darling River basin include the Gunnedah and Narrabri aquifers. An example of aquifers across Southern Murray–Darling Basin is shown in Figure P10.
Figure P10 Cross-section diagram of groundwater aquifers in the Southern Murray–Darling Basin
Sedimentary and alluvial aquifers are the most important for groundwater extraction, with nearly all of the extracted groundwater (more than 95%) coming from these aquifers. They have relatively high water holding capacity and hydraulic conductivity, and therefore are suited to extraction for use in irrigation and urban water supply. Most of the groundwater reported in the 2014 Account were from these aquifers. Groundwater quality is another significant quality that typically deteriorates down the groundwater flow path, constraining groundwater use to areas with acceptable water quality (primarily determined by low salinity).
The GAB is the largest groundwater basin in Australia. It underlies about one third of the MDB (Figure P2) and extends beyond the MDB drainage basin boundary to the north and west. The GAB contains confined aquifers at depth, with confining layers that can be at or near the land surface. The GAB provides vital water resources for domestic and town water supply, for stock use by the pastoral industry and water supplies for the operations of mining and petroleum industries and associated communities. The GAB is recharged in small areas of the MDB (along the southeastern edge of the GAB) where the aquifer layers are exposed at the land surface. Groundwater extraction and leakage from the GAB to the MDB are not represented in the 2014 Account, but may be represented in future accounts as an inter-basin transfer.
Fractured rock aquifers occur in the highland areas around the peripheries of the Murray–Darling Basin region (see Figure P9). In fractured rock aquifers, groundwater is stored in the fractures, joints, bedding planes and cavities of the rock mass and due to the difficulty of obtaining high yields from most fractured rocks, the volume of groundwater extracted from any one bore and in a given area is relatively low. In most fractured rock areas of the MDB, groundwater use is limited to stock and domestic supply. It is considered that the annual change in groundwater storage and annual groundwater flow out of fractured rock areas is of low significance to regional water balance and are not estimated in the 2014 Account.
More details about the groundwater resources within the MDB region are available in the Groundwater note.
Water supply
Urban water supply
Across the Murray–Darling Basin region, many towns and urban centres abstract water and then return treated urban wastewater to the river for subsequent use downstream. For example, on the Murrumbidgee River, average returns to surface water from Canberra are more than half of the Australian Capital Territory diversions from the river.
More details for urban water supply (allocated and non-allocated) and discharge to surface water within the MDB region are provided in Surface water note. Groundwater extractions for urban water supply are provided in the Groundwater note.
Irrigation water supply
The Murray–Darling Basin contains about 40% of Australia's farms and 70% of Australia's irrigated land area (Murray–Darling Basin Authority 2015i). Based on information collected for the National Water Account 2014, approximately 95% of consumptive surface water and 80% of groundwater is used for irrigation water supply. The region is home to several major irrigation areas including Murrumbidgee, Coleambally and Murray in New South Wales and the Goulburn–Murray in Victoria. For more information on these major irrigation schemes, refer to Murrumbidgee Irrigation, Coleambally Irrigation, Murray Irrigation and Goulburn-Murray Water websites.
In addition to these major irrigation schemes, there are many, relatively minor, irrigation schemes. Figure P11 provides details of the irrigation areas within the Murray–Darling Basin region.
There is an extensive infrastructure to supply water to irrigation water users in these irrigation schemes. This infrastructure links rivers and channels with the storages designed for irrigation water supply.
More details for Irrigation water supply within the MDB region are provided in the Irrigation note.
Figure P11 Irrigated areas within the Murray-Darling Basin region
(Map sources: Geoscience Australia irrigation gazetted areas and ABARES landuse map)