Murray–Darling basin

"Murray–Darling" redirects here. For the wine region, see Murray Darling.

Murray–Darling Basin
One of the three main rivers of the basin, the Darling, near Menindee
(click to enlarge map)
Length	3,375 km (2,097 mi)
Area	1,061,469 km2 (409,835 sq mi)
Geology
Age	69
Geography
Country	Australia
States and territories	List Queensland New South Wales Victoria South Australia, Australian Capital Territory
Rivers	List Murray Darling Murrumbidgee Warrego Lachlan Goulburn Campaspe Mitta Mitta Loddon and numerous other tributaries as listed in the table

The Murray–Darling Basin is a large geographical area in the interior of southeastern Australia, encompassing the drainage basin of the tributaries of the Murray River, Australia's longest river, and the Darling River, a right tributary of the Murray and Australia's third-longest river. The Basin, which includes six of Australia's seven longest rivers and covers around one-seventh of the Australian landmass, is one of the country's most significant agricultural areas providing one-third of Australia's food supply. Located west of the Great Dividing Range, it drains southwest into the Great Australian Bight and spans most of the states of New South Wales and Victoria, the Australian Capital Territory, and parts of the states of Queensland (the lower third) and South Australia (the southeastern corner).

The Basin is 3,375 kilometres (2,097 mi) in length, with the Murray River being 2,508 km (1,558 mi) long. Most of the 1,061,469 km² (409,835 sq mi) basin is flat, low-lying and far inland, and receives little direct rainfall. The many rivers it contains tend to be long and slow-flowing, and carry a volume of water that is large only by Australian standards.

The Snowy Mountains Scheme provides some security of water flows to the Murray–Darling Basin, providing approximately 2,100 gigalitres (7.4×10¹⁰ cu ft) of water a year to the Basin for use in Australia's irrigated agriculture industry, which is worth about A$3 billion per annum, representing more than 40% of the gross value of the nation's agricultural production.

The original inhabitants

The Basin was once home to a large number of Aboriginal people whose traditional lifestyle and cultures were gradually altered by the arrival of Europeans, while others were outright killed by the settlers. Although some tribes organised resistance, such as the Maraura, whose territory lay around the Rufus River above Renmark and the Tanganekald near The Coorong, they were eventually either killed, exiled, or succumbed to disease.

Native fauna

The Murray–Darling Basin is home to many native animal species. The true numbers may not be known, but a fairly confident estimate has been made of these animals and the current status of their population. The study found that there were:

• 80 species of mammals, with 62 extinct and 10 endangered
• 55 species of frogs, with 18 endangered
• 46 species of snakes, with five endangered
• five species of turtles, with none endangered
• 34 species of fish, with up to half of them either threatened or of conservation significance

Historical records show that the previous abundances of fish provided a reliable food source. The bountiful fish became concentrated when the early stages of a flood left shallow water across the floodplain. Today, roughly 24 native freshwater fish and another 15-25 marine and estuarine species are existent in the Basin, a very low biodiversity.

2018–2019 fish kill

Over Christmas 2018 and January 2019 there were two mass deaths of fish in the waters of the Basin, the first numbering 10,000, the second in the hundreds of thousands. Species affected were Murray cod, golden perch, silver perch and bony herring. Some blamed the draining of water from the Menindee Lakes by WaterNSW, with only 2.5% of the original water volume in the lakes being left; after the first fish kill, both the Department of Primary Industries (DPI) and WaterNSW blamed the ongoing drought affecting Australia, while the DPI blamed the second kill on a disruption of an algal bloom caused by a sudden fall in temperature.

2023 fish kill

In March 2023, millions of fish were reported dead along the Darling River at Menindee, following a heatwave. As the cleanup began, police attributed the cause to (naturally occurring) hypoxic blackwater. Initial investigations by the New South Wales Environment Protection Authority (EPA) included single water samples at six sites and were criticised as inadequate. Subsequently it was announced that the New South Wales government will treat the deaths as a "pollution incident", thus giving the EPA greater investigative powers; earlier testing was described as being primarily intended to ensure public safety.

Introduced species

Four varieties of carp were used to stock up fish dams. Since then they have made their way into the river systems, where they spread quite quickly. Human introduction, possibly by anglers using small carp illegally as live bait, has also increased their distribution. These fish are very mobile, breed rapidly and can survive in very shallow water and through long periods of very low dissolved oxygen content.

Carp are a problem because they feed by sucking gravel from the riverbed and taking all the edible material off it, before returning the rest to the water. This stirs up all the sediment, reducing the quality of the water. A project for developing daughterless carp shows promise for eliminating carp from the river system.

Cane toads have entered the upper reaches of the Darling Basin and there are several reports of individuals being found further down the system. Cane toads compete with native amphibians and are toxic to native carnivores.

Phyla canescens has invaded wetlands and floodplains with heavy clay soils in the Murray–Darling Basin, to the detriment of the native vegetation; the plant does best in habitats that are inundated occasionally, although it cannot compete with the grass Paspalum distichum and the sedge Eleocharis plana in more heavily inundated sites.

Physiography

This area is one of the physiographic provinces of the larger East Australian Basins division, and encompasses the smaller Naracoorte Platform and Encounter Shelf physiographic sections.

Total water flow in the Murray–Darling Basin 1885 to the present has averaged around 24,000 gigalitres (24,000 hm³; 19,000,000 acre⋅ft) per year. This is the lowest rate of the world's major river systems. About 6.0 percent of Australia's total rainwater falls into the Basin. In most years only half of this quantity reaches the sea and in dry years much less. Estimated total annual flows for the Basin have ranged from 5,000 gigalitres (5,000 hm³; 4,100,000 acre⋅ft) in 1902 to 57,000 gigalitres (57,000 hm³; 46,000,000 acre⋅ft) in 1956. Despite the magnitude of the Basin, the hydrology of the streams within it is quite varied.

These waters are divided into four types:

• The Darling and Lachlan basins. These have extremely variable flows from year to year, with the smallest annual flow being typically as little as 1 percent of the long-term mean and the largest often more than ten times the mean. Periods of zero flow in most rivers can extend to months and in the drier parts (Warrego, Paroo and Lower Darling Basins) to years. Flows in these rivers are not strongly seasonal. In the northern regions the majority of floods occur in the summer from monsoonal penetration. For most of the Darling and Lachlan catchments it is typical to see high or low flows begin in winter and extend to the following autumn (see El Niño). High water extraction rates for irrigation and mining have heavily compromised these rivers.
• The southwestern basins (Campaspe, Loddon, Avoca, Wimmera). These have a marked winter rainfall maximum and relatively lower precipitation variability than the Lachlan or Darling. However, the age and infertility of the soils mean that run-off ratios are exceedingly low (for comparison, around a tenth that of a European or North American catchment with a similar climate). Thus, variability of runoff is very high and most of the terminal lakes found in these basins very frequently dry up. Almost all runoff occurs in the winter and spring and, in the absence of large dams for regulation, these rivers are often seasonally dry during summer and autumn.
• A number of small catchments in South Australia, of which the largest are the Angas River flowing through Strathalbyn and the Finniss River further west, are part of the Murray–Darling Basin. These catchments lead to Lake Alexandrina, one of the lakes at the end of the Murray system. The Angas River is often dry in summer because of high levels of water extraction. The Finniss River has permanent flow into Lake Alexandrina but was cut off by a weir for several years of drought in the early 21st century.
• The Murray, Murrumbidgee and Goulburn (except the Broken River which resembles the southwestern basins) basins. Because these catchments have headwaters in alpine country with relatively young peaty soils, the runoff ratios are much higher than in other parts of the Basin. Consequently, although gross precipitation variability is no lower than in the Lachlan or Darling basins, runoff variability is markedly lower than in other parts of the Basin. Typically these rivers never cease to flow and the smallest annual flow is around 30 percent of the long-term mean and the largest around three times the mean. In most cases the flow peaks very strongly with the spring snow melt and troughs in mid-autumn.

The two principal rivers of the Basin, the Murray and Darling, bring water from the high ranges of the east and carry it west then south through long flat and dry inland areas, often resulting in alluvial channel wetlands, such as The (Great) Cumbung Swamp, at the terminus of the Lachlan and Murrumbidgee Rivers. Nevertheless, these waters are subject to major diversions for municipal drinking supplies and irrigated agriculture that began in the 1890s. Currently, 4 major reservoirs, 14 lock and weir structures, and five coastal barrages interject the water flowing down the Murray–Darling. Of the approximately 13,000 gigalitres (13,000 hm³; 10,500,000 acre⋅ft) of flow in the Basin, which studies have shown to be divertible, 11,500 gigalitres (11,500 hm³; 9,320,000 acre⋅ft) are removed for irrigation, industrial use, and domestic supply. Agricultural irrigation accounts for about 95 percent of the water removed, including for the growing of rice and cotton. This extraction is highly controversial among scientists in Australia, regarding the agriculture industry's high water use in a region extremely short of water (as much due to exceptionally low run-off coefficients as to low rainfall). These extensive irrigation systems require a reliable supply of water, not the unpredictable flows that characterise the Murray–Darling. These structures and irrigation implements were ideal when there was a steady flow of water. However, during "the Big Dry", as the early 2000s drought came to be known, Australian farmers experienced a scarcity unlike ever before. The drought was so severe that numerous rivers and streams such as the Murray–Darling stopped flowing. The Basin contains more than 30,000 wetlands. Eleven of these are protected under the Ramsar Convention of Wetlands of International Importance.

Rivers in the Murray–Darling Basin

• 
  Yarrawonga Weir on the Murray River forms Lake Mulwala, 2010
• 
  Darling River at Menindee, 2009
• 
  Warrego River at Cunnamulla, 2010
• 
  Barwon River at Collarenebri, 2008
• 
  Lake Burrendong, formed at the confluence of the Macquarie River and Cudgegong River, 1995
• 
  Macquarie River at Bathurst, 2009
• 
  Siphon irrigation of cotton on the Balonne River near St George, 2012
• 
  Maranoa River at Mitchell, 2005
• 
  Macintyre River in flood at Goondiwindi, 1921
• 
  Taemas Bridge across the Murrumbidgee River, 2011
• 
  Goodradigbee River in the valley below the Brindabella Ranges, 2005
• 
  Molonglo River at Acton in 1920, prior to the damming of the river to form Lake Burley Griffin.
• 
  Wakool River, near Kyalite, 2012
• 
  A footbridge of the Avoca River at Charlton, 2005
• 
  Goulburn River at Murchison, 2009
• 
  Ovens River at Porepunkah, 2007
• 
  Mitta Mitta River, downstream from Dartmouth Dam, 2007

The rivers listed below comprise the Murray–Darling Basin and its direct significant tributaries, with elevations of their confluence with the downstream river. The tributary with the highest elevation is Swampy Plain River that rises in the Snowy Mountains, below Mount Kosciuszko at an elevation of 2,120 metres (6,960 ft), and ends merging with the Murray River, descending 1,860 metres (6,100 ft).

The ordering of the Basin, from downstream to upstream, is:

Rivers of the Murray–Darling Basin
Catchment river							Elevation at confluence		River mouth	States	River length
	Tributary
		Tributary
			Tributary
				Tributary
					Tributary
						Tributary	m	ft			km	mi
Murray River									0	0			Southern Ocean	NSW, Vic, SA	2,375	1,476
	Darling River						35	115	Murray	NSW	1,472	915
		Paroo River					94	308	Darling	Qld, NSW	1,210	750
		Warrego River					98	322	Darling	Qld, NSW	1,380	860
			Langlo River				280	920	Warrego	Qld	440	270
			Nive River				336	1,102	Warrego	Qld	263	163
		Culgoa River					109	358	Darling	Qld, NSW	489	304
			Birrie River				115	377	Culgoa	Qld	197	122
		Barwon River (New South Wales)					110	360	Darling	NSW	700	430
			Bokhara River				113	371	Barwon	Qld, NSW	347	216
			Namoi River				130	430	Barwon	NSW	708	440
				Mooki River			264	866	Namoi	NSW	128	80
				Peel River (New South Wales)			286	938	Namoi	NSW	210	130
					Cockburn River		384	1,260	Peel	NSW	34	21
				Manilla River			349	1,145	Namoi	NSW	138	86
				Macdonald River (Bendemeer)			705	2,313	Namoi	NSW	169	105
					Cobrabald River		990	3,250	Macdonald	NSW	53	33
			Gwydir River				144	472	Barwon	NSW	488	303
				Horton River			270	890	Gwydir	NSW	128	80
				Moredun Creek			645	2,116	Gwydir	NSW	210	130
				Rocky River (New South Wales)			760	2,490	Gwydir	NSW	138	86
			Mehi River				145	476	Barwon	NSW	314	195
			Moonie River				149	489	Barwon	NSW	542	337
			Boomi River				152	499	Barwon	NSW, Qld	231	144
			Macquarie River				154	505	Barwon	NSW	960	600
				Castlereagh River			121	397	Macquarie	NSW	541	336
				Talbragar River			258	846	Macquarie	NSW	277	172
					Coolaburragundy River		271	889	Talbragar	NSW	156	97
				Little River (Dubbo)			271	889	Macquarie	NSW	122	76
				Bell River (New South Wales)			285	935	Macquarie	NSW	146	91
				Cudgegong River			342	1,122	Macquarie	NSW	250	160
				Turon River			406	1,332	Macquarie	NSW	117	73
					Crudine River		563	1,847	Turon	NSW	54	34
				Fish River (New South Wales)			668	2,192	Macquarie	NSW	119	74
					Campbells River		706	2,316	Fish	NSW	82	51
					Duckmaloi River		1,010	3,310	Fish	NSW	27	17
			Weir River (Queensland)				166	545	Barwon	Qld, NSW	197	122
			Balonne River				171	561	Barwon	Qld	479	298
				Maranoa River			207	679	Balonne	Qld	519	322
					Merivale River		401	1,316	Maranoa	Qld	205	127
				Condamine River			256	840	Balonne	Qld	657	408
			Macintyre River				224	735	Barwon	NSW, Qld	319	198
				Dumaresq River			227	745	Macintyre	NSW	214	133
					Macintyre Brook		241	791	Dumaresq	Qld	165	103
					Beardy River		354	1,161	Dumaresq	NSW	90	56
					Pike Creek (Queensland)		360	1,180	Dumaresq	Qld	117	73
					Mole River (New South Wales)		363	1,191	Dumaresq	Qld	73	45
						Deepwater River	601	1,972	Mole	NSW	84	52
						Bluff River (New South Wales)	614	2,014	Mole	NSW	13	8.1
					Severn River (Queensland)		375	1,230	Dumaresq	Qld, NSW	90	56
				Severn River (New South Wales)			284	932	Macintyre	NSW	52	32
					Beardy Waters		884	2,900	Severn (NSW)	NSW	70	43
		Bogan River					111	364	Darling	NSW	617	383
			Little River (Parkes)				305	1,001	Bogan	NSW	319	198
	Murrumbidgee River						55	180	Murray	NSW, ACT	1,488	925
		Lachlan River					68	223	Murrumbidgee	NSW	1,440	890
			Belubula River				262	860	Lachlan	NSW	165	103
			Boorowa River				301	988	Lachlan	NSW	134	83
			Abercrombie River				375	1,230	Lachlan	NSW	130	81
				Isabella River (New South Wales)			479	1,572	Abercrombie	NSW	51	32
				Bolong River			589	1,932	Abercrombie	NSW	60	37
		Tumut River					220	720	Murrumbidgee	NSW	182	113
			Goobarragandra River				272	892	Tumut	NSW	56	35
			Doubtful Creek				1,290	4,230	Tumut	NSW	15	9.3
		Yass River					345	1,132	Murrumbidgee	NSW	139	86
		Goodradigbee River					345	1,132	Murrumbidgee	NSW	105	65
		Crookwell River					430	1,410	Murrumbidgee	NSW	78	48
		Molonglo River					440	1,440	Murrumbidgee	NSW, ACT	115	71
			Jerrabomberra Creek				554	1,818	Molonglo	NSW, ACT	35	22
			Sullivans Creek				556	1,824	Molonglo	NSW, ACT	13	8.1
			Queanbeyan River				567	1,860	Molonglo	NSW, ACT	104	65
		Cotter River					460	1,510	Murrumbidgee	ACT	74	46
			Paddys River (Australian Capital Territory)				477	1,565	Cotter	ACT	28	17
				Tidbinbilla River			618	2,028	Paddys	ACT	13	8.1
				Gibraltar Creek			647	2,123	Paddys	ACT	13	8.1
		Gudgenby River					573	1,880	Murrumbidgee	ACT	35	22
			Naas River				631	2,070	Gudgenby	ACT	26	16
			Orroral River				842	2,762	Gudgenby	ACT	15	9.3
		Bredbo River					695	2,280	Murrumbidgee	NSW	52	32
			Strike-a-Light River				733	2,405	Bredbo	NSW	38	24
		Numeralla River					706	2,316	Murrumbidgee	NSW	94	58
			Big Badja River				735	2,411	Numeralla	NSW	32	20
			Kybeyan River				745	2,444	Numeralla	NSW	36	22
	Wakool River						58	190	Murray	NSW	363	226
		Niemur River					63	207	Wakool	NSW	155	96
	Edward River (an anabranch)						61	200	Murray	NSW	383	238
	Little Murray River (Victoria)						67	220	Murray	Vic	46	29
	Loddon River						71	233	Murray	Vic	392	244
	Avoca River						74	243	Murray	Vic	270	170
	Little Murray River (New South Wales)						75	246	Murray	NSW	22	14
	Goulburn River, Victoria						100	330	Murray	Vic	654	406
		Broken River (Victoria)					118	387	Goulburn	Vic	225	140
		Yea River					162	531	Goulburn	Vic	122	76
			Murrindindi River				186	610	Yea	Vic	26	16
		Acheron River					190	620	Goulburn	Vic	84	52
			Little River (Cathedral Range)				207	679	Acheron	Vic	22	14
			Steavenson River				264	866	Acheron	Vic	20	12
				Taggerty River			368	1,207	Steavenson	Vic	18	11
		Rubicon River					200	660	Goulburn	Vic	43	27
			Royston River				381	1,250	Rubicon	Vic	19	12
		Big River (Goulburn River, Victoria)					259	850	Goulburn	Vic	62	39
		Delatite River					260	850	Goulburn	Vic	83	52
		Howqua River					265	869	Goulburn	Vic	66	41
		Jamieson River					294	965	Goulburn	Vic	33	21
	Campaspe River						123	404	Murray	Vic	232	144
		Coliban River					183	600	Campaspe	Vic	89	55
			Little Coliban River				501	1,644	Coliban	Vic	12	7.5
	Ovens River						125	410	Murray	Vic	191	119
		King River, Victoria					142	466	Ovens	Vic	126	78
		Buffalo River (Victoria)					206	676	Ovens	Vic	65	40
			Dandongadale River				279	915	Buffalo	Vic	41	25
			Catherine River (Victoria)				392	1,286	Buffalo	Vic	25	16
		Buckland River (Victoria)					274	899	Ovens	Vic	38	24
	Kiewa River						156	512	Murray	Vic, NSW	109	68
	Mitta Mitta River						180	590	Murray	Vic	204	127
		Dart River (Victoria)					452	1,483	Mitta Mitta	Vic	29	18
		Big River (Mitta Mitta River, Victoria)					655	2,149	Mitta Mitta	Vic	52	32
		Cobungra River					656	2,152	Mitta Mitta	Vic	55	34
			Victoria River (Victoria)				830	2,720	Cobungra	Vic	25	16
	Tooma River						238	781	Murray	NSW	74	46
	Swampy Plain River						269	883	Murray	NSW, Vic	59	37
		Geehi River					439	1,440	Swampy Plain	Vic	47	29

Murray–Darling Basin Initiative

Background

The Basin affects five states and territory governments, which according to the Constitution, are responsible for managing water resources. The River Murray Commission was established in 1917. Under the River Murray Waters Agreement, which did not include Queensland though about a quarter of the Basin lays in the state, the commission was an advisory body with no authority for enforcement of provisions. For a long time the commission was only concerned with water quantity until salinity became a problem. This led to minor reforms in 1982 in which water quality became part of the commission's responsibilities.

However, it was soon recognised that a new organisational structure which considered the national perspective was needed for effective management. The Murray–Darling Basin Agreement was first adopted in 1985 but it wasn't until 1993 that its full legal status was enacted. The Agreement led to the creation of a number of new organisations under what is known as the Murray–Darling Basin Initiative. These included the Murray–Darling Basin Ministerial Council and the Murray–Darling Basin Commission.

Murray–Darling Basin Plan

The Murray–Darling Basin Authority (MDBA) was formed in 2008 to manage the Murray–Darling Basin in an integrated and sustainable manner. The MDBA is responsible for preparing and overseeing a legally-enforceable management plan. In October 2010, MDBA released a draft Murray–Darling Basin Plan (MDBP) for consultation. On 22nd November 2012, Tony Burke signed the Murray–Darling Basin Plan, which passed the Australian Parliament's disallowance period on 19 March 2013.

Community consultation

The MDBA's draft Murray–Darling Basin Plan, titled the Guide to the Proposed Murray–Darling Basin Plan, was released in October 2010 as the first part of a three-stage process to address the problems of the Murray–Darling Basin. The Plan was in response to the 2000s Australian drought, and designed to secure the long-term ecological health of the Murray–Darling Basin. This entailed cutting existing water allocations and tree growth environmental flows. The Basin Plan was designed to set environmentally sustainable limits on the quantities of water that may be taken from Basin water resources, to set Basin-wide environmental, water quality and salinity objectives, to develop efficient water trading regimes across the Basin, to set requirements for state water resource plans and to improve water security for all Basin users. It also intends to minimise social and economic impacts whilst achieving the plan's environmental outcomes.

With the release of the Guide to the Proposed Murray–Darling Basin Plan there have been a number of protests and voiced concerns about the plan in rural towns that the MDBA visited to present the plan to consultation meetings. More than 5,000 people attended a MDBA meeting in Griffith where Griffith Mayor, Mike Neville, said the plan would "obliterate" Murrumbidgee valley communities. Other groups also echo this feeling, such as the Victorian Farmers Federation and Wine Group Growers' Australia. Conversely, support for the Murray–Darling Basin plan has been received by various groups, including Australian Conservation Foundation, and Environment Victoria.

New legal advice from Commonwealth government lawyers is changing the plan. The Government's interpretation is that the plan must give equal weight to the environmental, social, and economic impacts of proposed cuts to irrigation.

Environmentalists and South Australian irrigators, at the end of the river in South Australia, say that the authority should stick to its original figure.

In October 2010, a parliamentary inquiry into the economic impacts of the plan was announced.

In late October 2010 the Water Minister, Tony Burke, played down the prospect of a High Court challenge to the Murray–Darling Basin plan, as confusion continued over new legal advice released by the Government. In response to community concerns that MDBA had put environmental issues first over social and economic needs, Burke released new advice on the requirements of the Water Act. Burke stated that the Act does allow for the authority to "optimise" the needs of all three areas, but constitutional lawyer, George Williams, had cast doubts over the interpretation of the laws, stating it could be subject to a legal challenge.

The MDBA announced in November 2010 that it might be forced to push back the release of its final plan for the river system until early 2012.

The then MDBA chairman, Mike Taylor, reassured the public meeting that more work is being done to look at how the proposed cuts would affect regional communities. He stated: "Importantly, we want to make sure the social and economic impacts—which under any sort of scenario is very significant—were fully teased out". Taylor resigned as he allegedly believed that the overriding principle should be the environmental outcome which was in conflict with the Gillard Government and following a period of sustained criticism of the Authority and the implementation of the proposed draft Basin plan. He was replaced by former New South Wales Planning Minister, Craig Knowles.

In late May 2012, the revised plan was forwarded to state water ministers. It did not alter the recommendation to cut 2,750 gigalitres (2.75 km³; 2,230,000 acre⋅ft) of water entitlements.

Following much negotiation between the Commonwealth and State governments and numerous submissions from interested stakeholders and the community, the Basin Plan became law in November 2012 and can now be implemented.

See also

• Climate change in Australia
• Drought in Australia
• Murray–Darling Cap
• List of drainage basins of Australia
• List of Darling River distances
• List of Murray River crossings
• List of Murray River distances
• List of Murrumbidgee River distances
• Murray Basin, the geological sedimentary basin

External links

• Murray–Darling Basin Authority
• Murray–Darling Basin Water Budget Project
• Murray Darling Freshwater Research Centre
• River Murray Water Restrictions
• Murray Outback - Guide to the major towns on the Murray and Murray Outback Region.
• Save the Murray - lobby group
• Murray Darling Basin Resources
• The Basin Plan
• Guide to the Proposed Basin Plan
• Guide to the Basin Plan, Volumes 1 - 21
• Basin Plan - lobby group

News

• "Fire, Flood and Acid Mud", Catalyst, Australian Broadcasting Corporation, archived from the original on 19 April 2016