Murray Mouth

Murray mouth
Murray mouth
	The narrow Murray Mouth in the background as viewed from Hindmarsh Island, November 2006
	Murray mouth
Location	Australia
Coordinates	Coordinates: 35°35′00″S138°53′00″E / 35.583333°S 138.883333°E
River sources	Murray River
Basin countries	Australia
Average depth	2.4 m (7.9 ft) as of 1985

Last updated February 22, 2022

Murray Mouth is the point at which the River Murray meets the Southern Ocean. The Murray Mouth's location is changeable. Historical records show that the channel out to sea moves along the sand dunes over time. At times of greater river flow and rough seas, the two bodies of water would erode the sand dunes to create a new channel leaving the old one to silt and disappear.

Description

The mouth of the Murray River is about 10 kilometres (6.2 miles) south east of Goolwa and about 75 kilometres (47 miles) south-south-east of the Adelaide city centre in the gazetted localities of Coorong and Goolwa South.^[2] The mouth is an opening in the coastal dune system which separates the river system from the ocean and which extends from near Goolwa in a south-easterly direction along the continental coastline for about 145 kilometres (90 miles). The mouth divides the dune system into two peninsulas. The peninsula on the west side is Sir Richard Peninsula which terminates at the mouth with a point named Pullen Spit. The peninsula on the east side is Younghusband Peninsula which terminates at the mouth with a point known in some sources as Sleepy Hollow.^[1]^[3]^[4]^[5]^[6]^[7]

Water flows throughout the mouth from two directions. Firstly, the flow from the west passes along a passage known as the Goolwa Channel which is bounded by Hindmarsh Island to its north side. Secondly, the flow from the east passes along a passage known as the Coorong Channel. The Coorong Channel itself is fed by the Mundoo Channel which passes between Hindmarsh Island and Mundoo Island to the north, and by the Tauwitchere Channel to the east.^[3]^[5]

Natural history

From the Pleistocene about 2.5 million years ago, the Murray River terminated in a freshwater lake called Lake Bungunnia which included the area now occupied by the South Australia/New South Wales border. The lake drained less than a million years ago, creating the current course.^[8] It was suggested that the Murray may have taken a different course to the ocean, via Burra, South Australia and emptied into the Spencer Gulf,^[9] before being 'defeated' by the rise of the Mt Lofty Ranges. This has been studied by analysing the uplift date of the Mt Lofty Ranges and other geological data and found that this was not likely to be the case.^[10]

History

European discovery and use

During expeditions in 1829–30, Charles Sturt explored the Murray and its westward-flowing tributaries, finding that the mouth of the Murray was barely navigable to shipping.^[11] During the later 19th century with the discovery of gold, and the development of sheep and wheat farming along the Murray and its tributaries, the river became a major thoroughfare for the carriage of goods and produce. During the peak period of Murray River commerce (roughly 1855 to 1920) and before the development of rail and road transport, the Murray Mouth with its complex and unpredictable interaction between shallow, shifting and variable currents and the open sea, presented a major impediment to traffic between Adelaide and the Murray settlements, and many vessels foundered or were wrecked there.

Water flow

River Murray water is used by farmers for irrigation in four of Australia's states, as well as supplying water to most towns along the river, and many further away through various pipelines. It has been widely accepted that too much water is being extracted; however business and political concerns make it difficult to remedy the problem. A visible symptom of the over-extraction of river water is the closing of the Murray Mouth.

From October 2002 until 2010 dredging machines operated at the Murray Mouth.^[12] Between 2002 and 2006, two machines operated moving sand from the channel to maintain a minimal flow from the sea and into the Coorong's lagoon system.^[12] Without the 24-hour dredging, the mouth was at risk of becoming silted and closing, cutting the supply of fresh seawater into the Coorong, which would then warm up, stagnate and die.^[12]

In mid-2006 the dredging was scaled back as a result of the improved conditions at the mouth. Now only one dredging machine operates, and permission was granted to one commercial operator to navigate the channel between Goolwa and the Coorong, passing the mouth. This operation finished in 2010.^[12]

Dredging was scheduled to resume in January 2015.^[12]

Dredging continues at a cost between $3m to $6m annually.

Protected area status and other arrangements

Australian government

The Murray Mouth is immediately adjoined on its northern and eastern sides by the boundary of the Coorong and Lakes Alexandrina and Albert Wetland Ramsar site.^[13]

South Australian government

The Murray Mouth is located within a special purpose area within the Encounter Marine Park and is immediately adjoined on its northern and eastern sides by the boundary of the Coorong National Park.^[14]^[15]

Non-statutory arrangements

The Murray Mouth is adjoined on its northern and eastern sides by the boundary of the Coorong Important Bird Area which is an area considered by Birdlife International to be a place of ‘international significance for the conservation of birds and other biodiversity.’^[16]^[17]

Citations and references

Notes

1 2 DMH, 1985, Chart 8
↑ "Search result for "Murray Mouth (Estuary) " (Record no. SA0048047) with the following layers selected - "Suburbs and Localities" and " Place names (gazetteer)"". Property Location Browser. Government of South Australia. Archived from the original on 12 October 2016. Retrieved 22 June 2016.
1 2 BIA, 2005, page 27
↑ DMH, 1985, Chart 7
1 2 DMH, 1985, Chart 9
↑ "Pullen Spit". Gazetteer of Australia online. Geoscience Australia, Australian Government.
↑ "Sleepy Hollow". Gazetteer of Australia online. Geoscience Australia, Australian Government.
↑ "Murray River's natural history dates back 130 million years". Discover Murray River. Retrieved 25 July 2016.
↑ Williams and Goode, 1978, Possible western outlet for an ancient Murray River in South Australia, Search, 9 442-447
↑ Stevenson and Brown, 1989, "The ancient Murray River system", Journal of Australian Geology and Geophysics, 11, 387–395
↑ Gibbney, H.J. (1967). "Sturt, Charles (1795–1869)". Australian Dictionary of Biography . Melbourne University Press. ISSN 1833-7538 . Retrieved 4 April 2010– via National Centre of Biography, Australian National University.
1 2 3 4 5 http://www.naturalresources.sa.gov.au/samurraydarlingbasin/projects/all-projects-map/keeping-the-murray-mouth-open ^{[ dead link ]}
↑ "Coorong and Lakes Alexandrina and Albert Wetland Ramsar site" (PDF). Department of Environment Water and Natural Resources. 28 January 2014. Retrieved 19 January 2015.
↑ DEWNR, 2012, page 2 of 6
↑ "Coorong National Park - Goolwa Barrage to Long Point Map" (PDF). Department of Environment, Water and Natural Resources. Retrieved 29 July 2015.
↑ "Important Bird Areas factsheet: Coorong". BirdLife International. Retrieved 19 January 2015.
↑ "Sites - Important Bird and Biodiversity Areas (IBAs)". BirdLife International. Retrieved 19 January 2015.

Related Research Articles

The Murray River is a river in south-eastern Australia. It is Australia's longest river at 2,508 km (1,558 mi) extent. Its tributaries include five of the next six longest rivers of Australia. Together with that of the Murray, the catchments of these rivers form the Murray–Darling basin, which covers about one-seventh the area of Australia. It is widely considered Australia's most important irrigated region.

Coorong National Park Protected area in South Australia

Coorong National Park is a protected area located in South Australia about 156 kilometres (97 mi) south-east of Adelaide, that predominantly covers a coastal lagoon ecosystem officially known as The Coorong and the Younghusband Peninsula on the Coorong's southern side. The western end of the Coorong lagoon is at the Murray Mouth near Hindmarsh Island and the Sir Richard Peninsula, and it extends about 130 kilometres (81 mi) south-eastwards. Road access is from Meningie. The beach on the coastal side of the peninsula, the longest in Australia, is also commonly called The Coorong.

Lake Alexandrina is a coastal freshwater lake located between the Fleurieu and Kangaroo Island and Murray and Mallee regions of South Australia, about 100 kilometres (62 mi) south-east of Adelaide. The lake adjoins the smaller Lake Albert and a coastal lagoon called The Coorong to its southeast, before draining into the Great Australian Bight via a short, narrow opening known as Murray Mouth.

Lake Albert, also known by its Ngarrindjeri name, Yarli, is a notionally fresh water lake near the mouth of the Murray River in South Australia. It is filled by water flowing in from the larger Lake Alexandrina at its mouth near Narrung. It is separated on the south by the Narrung Peninsula from the salt-water Coorong. The only major town on the lake is Meningie. Lakes Alexandrina and Albert are together known as the Lower Lakes.

Encounter Bay, once known as Ramong to the Ramindjeri people, is a bay in the Australian state of South Australia located on the state's south central coast about 100 kilometres (62 mi) south of the state capital of Adelaide. It was named by Matthew Flinders after his encounter on 8 April 1802 with Nicolas Baudin, the commander of the Baudin expedition of 1800–03. It is the site of both the mouth of the River Murray and the regional city of Victor Harbor. It is one of four "historic bays" located on the South Australian coast.

Hindmarsh Island is an inland river island located in the lower Murray River near the town of Goolwa, South Australia.

Goolwa is a historic river port on the Murray River near the Murray Mouth in South Australia, and joined by a bridge to Hindmarsh Island. The name "Goolwa" means "elbow" in Ngarrindjeri, the local Aboriginal language, and the area was known as "The Elbow" to the early settlers.

Currency Creek is a township and locality in South Australia on the western shore of Lake Alexandrina about 6 km north of Goolwa, beside a seasonal stream bearing the same name - Currency Creek - which flows into Lake Alexandrina. The locality includes the headland named Finniss Point which separates the mouths of Currency Creek and the Finniss River.

Coorong is a locality in the Australian state of South Australia which is associated with the lagoon known as the Coorong in the south-east of the state and which overlooks the continental coastline from the mouth of the Murray River about 80 kilometres south-east of the state capital of Adelaide to the immediate north of the town of Kingston SE extending for a distance of at least 140 kilometres (87 mi).

Younghusband Peninsula Place in South Australia

Younghusband Peninsula is a long narrow peninsula in South Australia. It separates the Coorong Channel, the Tauwitchere Channel and the Coorong which are part of the estuary of the River Murray from the Southern Ocean which including water bodies such as Encounter and Lacepede Bays. It lies entirely within the Coorong National Park. The peninsula is over 110 kilometres (68 mi) long, but less than 3 kilometres (1.9 mi) wide at its widest point. Its narrowest point is less than 350 metres (1,150 ft) wide. The Younghusband Peninsula, together with the Sir Richard Peninsula on the western side of the Murray Mouth, are the coastal dune system that forms the continental coastline from near Goolwa in the north west to about 35 kilometres north of Kingston SE in the south east. Younghusband Peninsula was named after William Younghusband, M.P.

Wellington Weir was a weir proposed for the River Murray several kilometres south of the town of Wellington, South Australia, immediately upstream from where the river enters Lake Alexandrina.

Clayton Bay is a town in South Australia located on Lake Alexandrina and the Lower Lakes, north of the north-east tip of Hindmarsh Island about 87 kilometres (54 mi) by road from Adelaide and 12 kilometres (7 mi) upstream from Goolwa and the Murray Mouth.

The Goolwa Barrages comprise five barrage structures in the channels separating Lake Alexandrina from the sea at the mouth of the River Murray and the Coorong in South Australia. They were constructed principally to reduce salinity levels in the lower reaches of the River Murray, Lake Alexandrina and Lake Albert, but also to stabilise the river level, for both upstream irrigation and pumping.

Water Witch was a single-masted vessel rigged as a cutter built during 1835 in Van Diemen's Land and sunk in 1842 whilst moored in the River Murray at Moorundie, south of Blanchetown in South Australia (SA). Her wreck site was discovered in 1982 and received statutory protection as a historic shipwreck in 1983. The wreck site was the subject of an underwater survey in March 1984. She was the first European vessel to enter the River Murray via its mouth, her role in the charting of the lower reaches of the River Murray including Lake Alexandrina whilst under the command of William Pullen and her association with Edward John Eyre.

Mud Islands Game Reserve is a protected area in South Australia covering ten islands at the southern side of Lake Alexandrina about 19 kilometres south-east of Goolwa. The game reserve is described as providing ‘an ideal habitat for water birds, particularly waterfowl’ and that ‘duck shooting is permitted during open season.’ Since 2000, the game reserve has been located within the boundaries of the gazetted locality, Coorong.

Goolwa South is a locality in the Australian state of South Australia located about 67 kilometres south of the state capital of Adelaide on both on the southern continental coastline and the south-western coast of Lake Alexandrina. It occupies the full extent of the Sir Richard Peninsula, land to the immediate west and part of the Goolwa Channel in the lake system to its north.

Goolwa North is a locality in the Australian state of South Australia located about 66 kilometres south of the state capital of Adelaide and 2.5 kilometres northeast of the centre of the municipal seat of Goolwa overlooking the following water bodies in the Murray River system - Currency Creek to the north and the channel known as Goolwa or the Lower Murray to the south-east.

Mundoo Island is a locality in the Australian state of South Australia located on Mundoo Island and some adjoining water at the southern end of Lake Alexandrina about 87 kilometres (54 mi) south-east of the state capital of Adelaide.

The Finniss River drains part of the east side of Fleurieu Peninsula into Lake Alexandrina in South Australia. It is part of the Murray–Darling basin.

References

Boating Industry Association of South Australia (BIA); South Australia. Department for Environment and Heritage (2005), South Australia's waters an atlas & guide, Boating Industry Association of South Australia, ISBN 978-1-86254-680-6
South Australia. Department of Marine and Harbors (DMH) (1985), The Waters of South Australia a series of charts, sailing notes and coastal photographs, Dept. of Marine and Harbors, South Australia, ISBN 978-0-7243-7603-2
"Encounter Marine Park Management plan summary" (PDF). Department of Environment, Water and Natural Resources (DEWNR). 2012. Retrieved 17 June 2014.