Everything about The Murray River totally explained
The
Murray River, or
River Murray and sometimes informally referred to as the "Mighty Murray", is
Australia's largest
river in its own right. At 2,575
kilometres (1,600
miles) in length, the Murray rises in the
Australian Alps, draining the western side of Australia's highest mountains and, for most of its length, meanders across Australia's inland plains, forming the border between
New South Wales and
Victoria as it flows to the northwest, before turning south for its final 500 kilometres or so into
South Australia
then ends at the mouth at
Lake Alexandrina.
The waters of the Murray flow through several lakes that fluctuate in
salinity (and were often fresh until recent decades) including
Lake Alexandrina and
The Coorong before emptying through the
Murray Mouth into the southeastern portion of the
Indian Ocean, often referenced on Australian maps as the
Southern Ocean, near
Goolwa. The draining of Lake Bungunia approximately 0.5 million years ago must have been a dramatic event. Deep clays deposited by the lake are evident in cliffs around Chowilla in
South Australia. Considerably higher rainfall would have been required to keep such a lake full; the draining of Lake Bungunia appears to mark the end of a wet phase in the history of the
Murray-Darling Basin and the onset of widespread arid conditions similar to today. A species of
Neoceratodus lungfish existed in Lake Bungunia (McKay & Eastburn, 1990); today
Neoceratodus lungfish are only found in several
Queensland rivers.
Cadell Fault and formation of the Barmah Red Gum Forests
The famous Barmah Red Gum Forests owe their existence to the Cadell Fault. About 25,000 years BP, displacement occurred along the Cadell fault, raising the eastern edge of the fault (which runs north-south) 8-12 metres above the floodplain. This created a complex series of events. A section of the original Murray River channel immediately behind the fault was abandoned, and exists today as an empty channel known as Green Gully. The Goulburn River was dammed by the southern end of the fault to create a natural lake. The Murray River flowed to the north around the Cadell Fault, creating the channel of the
Edward River which exists today and through which much of the Murray River's waters still flow. Then the natural dam on the Goulburn River failed, the lake drained, and the Murray River avulsed to the south and started to flow through the smaller Goulburn River channel, creating "The Barmah Choke" and "The Narrows" (where the river channel is unusually narrow), before entering into the proper Murray River channel again.
This complex series of events however divert attention from the primary result of the Cadell Fault. The primary result of the Cadell Fault is that the west-flowing water of the Murray River strikes the north-south running fault and diverts both north and south around the fault in the two main channels (Edward and ancestral Goulburn) as well as a fan of small streams, and regularly floods a large amount of low-lying country in the area. These conditions are perfect for River Red Gums, which rapidly formed forests in the area. Thus the displacement of the Cadell Fault 25,000 BP lead directly to the formation of the famous Barmah River Red Gum Forests
The Barmah Choke and The Narrows mean the amount of water that can travel down this part of the Murray River is restricted. In times of flood and high irrigation flows the majority of the water, in addition to flooding the Red Gum forests, actually travels through the Edward River channel. The Murray River hasn't had enough flow power to naturally enlarge The Barmah Choke and The Narrows to increase the amount of water they can carry.
The town of
Barmah, Victoria is unusual in that it's north of part of New South Wales, although everywhere else Victoria is south of New South Wales. Echuca on the map above is very close to Barmah.
The Cadell Fault is quite noticeable as a continuous, low, earthen embankment as one drives into Barmah from the west, although to the untrained eye it may appear man-made.
Murray Mouth
The Murray Mouth is the point at which the Murray River empties into the sea. Since the early
2000s,
dredging machines have operated at the Murray Mouth, moving sand from the channel to maintain a minimal flow from the sea and into the
Coorong's lagoon system. Without the 24 hour dredging, the Mouth would silt up and close, cutting the supply of fresh sea-water into the
Coorong, which would then warm up, stagnate and die.
Mythology
Being one of the major river systems in one of the driest continents of Earth, the Murray has significant cultural relevance to
Indigenous Australians. According to the peoples of
Lake Alexandrina, the Murray was created by the tracks of the Great Ancestor,
Ngurunderi, as he pursued
Pondi, the
Murray Cod. The chase originated in the interior of New South Wales. Ngurunderi pursued the fish (who, like many totem animals in Aboriginal myths, is often portrayed as a man) on rafts (or
lala) made from
red gums and continually launched spears at his target. But Pondi was a wily prey and carved a weaving path, carving out the river's various tributaries. Ngurundi was forced to beach his rafts, and often create new ones as he changed from reach to reach of the river.
At Kobathatang, Ngurunderi finally got lucky, and struck Pondi in the tail with a spear. However, the shock to the fish was so great it launched him forward in a straight line to a place called Peindjalang, near
Tailem Bend. Eager to rectify his failure to catch his prey, the hunter and his two wives (sometimes the escaped sibling wives of
Waku and Kanu) hurried on, and took positions high on the cliff on which Tailem Bend now stands. They sprung an ambush on Pondi only to fail again. Ngurunderi set off in pursuit again, but lost his prey as Pondi dived into Lake Alexandrina. Ngurunderi and his women settled on the shore, only to suffer bad luck with fishing, being plagued by a water fiend known as
Muldjewangk. They later moved to a more suitable spot at the site of present-day
Ashville. The twin summits of
Mount Misery are supposed to be the remnants of his rafts, they're known as
Lalangengall or
the two watercraft.
Remarkably, this story of a hunter pursuing a
Murray cod that carved out the Murray persists in numerous forms in various language groups that inhabit the enormous area spanned by the Murray system. The
Wotojobaluk people of Victoria tell of
Totyerguil from the area now known as
Swan Hill who ran out of spears while chasing
Otchtout the cod.
Exploration
The first Europeans to explore the river were
Hamilton Hume and William Hovell, who crossed the river where
Albury now stands in
1824:
Hume named it the
Hume River after his father. In
1830 Captain Charles Sturt reached the river after travelling down its tributary the
Murrumbidgee River and named it the
Murray River in honour of the then British
Secretary of State for War and the Colonies Sir
George Murray, not realising it was the same river that Hume and Hovell had encountered further upstream. Sturt continued down the remaining length of the Murray to finally reach
Lake Alexandrina and the river's mouth. The area of the
Murray Mouth was explored more thoroughly by Captain
Collet Barker in
1831. In 1852
Francis Cadell built a canoe and set off to become the first European to travel the whole length of the river.
In
1858 the Government
Zoologist,
William Blandowski, along with
Gerard Krefft, explored the lower reaches of the Murray and Darling rivers, compiling a list of
birds and
mammals. During the
expedition they accumulated 17,400 specimens and described several new species.
River transport
The lack of an
estuary means that shipping can't enter the Murray from the sea. However in the
19th century the river used to support a substantial commercial trade using shallow-draft
steamboats, the first trips being made by two boats from South Australia on the spring flood of
1853. One vessel,
Lady Augusta reached
Swan Hill while another,
Mary Ann made it as far as
Moama (near
Echuca). In
1855 a steamer carrying gold-mining supplies reached Albury but Echuca was the usual turn-around point though small boats continued to link with up-river ports such as
Tocumwal,
Wahgunya and Albury.
The arrival of steamboat transport was welcomed by pastoralists who had been suffering from a shortage of transport due to the demands of the gold fields. By
1860 a dozen steamers were operating in the high water season along the Murray and its tributaries. Once the
railway reached Echuca in
1864, the bulk of the
woolclip from the
Riverina was transported via river to Echuca and then south to Melbourne. The Murray was plagued by "snags", fallen trees submerged in the water, and considerable efforts were made to clear the river of these threats to shipping by using
barges equipped with steam-driven
winches. In recent times, efforts have been made to restore many of these "snags" by placing dead gum trees back into the river. The primary purpose of this is to provide habitat for fish species whose breeding grounds and shelter were eradicated by the removal of "snags".
The volume and value of river trade made Echuca Victoria's second port and in the decade from
1874 it underwent considerable expansion. By this time up to thirty steamers and a similar number of barges were working the river in season. River transport began to decline once the railways touched the Murray at numerous points. The unreliable levels made it impossible for boats to compete with the rail and later
road transport. However, the river still carries pleasure boats along its entire length.
Today, most traffic on the river is recreational. Small private boats are used for
water skiing and fishing.
Houseboats are common, both commercial for hire and privately owned. There are a number of both historic
paddle steamers and newer boats offering cruises ranging from a half-hour to 5 days.
River crossings
The Murray River has been a significant barrier to land-based travel and trade. Many of the ports for transport of goods along the Murray have also developed as places to cross the river, either by bridge or ferry.
Water storage and irrigation
Small-scale pumping plants began drawing water from the Murray in the
1850s and the first large-volume plant was constructed at Mildura in
1887. The introduction of pumping stations along the river promoted an expansion of
farming and led ultimately to the development of
irrigation areas (including the
Murrumbidgee Irrigation Area). In
1915 the three Murray states — New South Wales, Victoria and South Australia — signed the River Murray Agreement which proposed the construction of storage reservoirs in the river's headwaters as well as at
Lake Victoria near the South Australian border. Along the intervening stretch of the river a series of
locks and
weirs were built. These were originally proposed to support navigation even in times of low water, but river-borne transport was already declining due to improved road and rail systems.
In 2006 the state government of
South Australia revealed their plan to investigate the construction of the controversial
Wellington Weir.
Locks
Lock 1 was completed near
Blanchetown in
1922.
Torrumbarry Weir downstream of
Echuca began operating in December
1923. Of the numerous locks that were proposed, only thirteen were completed; Locks 1 to 11 on the stretch downstream of
Mildura, Lock 15 at
Euston and Lock 26 at Torrumbarry. Construction of the remaining weirs purely for navigation purposes was abandoned in
1934. The last lock to be completed was Lock 15, in
1937.
Lock 11, just downstream of Mildura, creates a 100
kilometre long lock pool which aided irrigation pumping from Mildura and
Red Cliffs. Each lock has a navigable passage next to it through the weir, which is opened during periods of high river flow, when there's too much water for the lock. The weirs can be completely removed, and the locks completely covered by water during flood conditions. Lock 11 is unique in that the lock was built inside a bend of the river, with the weir in the bend itself. A Channel was dug to the lock, creating an island between it and the weir. The weir is also of a different design, being dragged out of the river during high flow, rather than lifted out.
Four large reservoirs were built along the Murray; in addition to Lake Victoria (completed late
1920s) is
Lake Hume near
Albury-Wodonga (completed
1936),
Lake Mulwala at
Yarrawonga (completed
1939) and
Lake Dartmouth, which is actually on the
Mitta Mitta River upstream of Lake Hume (completed
1979). The Murray also receives water from the complex dam and pipeline system of the
Snowy Mountains Scheme.
These dams inverted the patterns of the river's natural flow from the original winter-spring flood and summer-autumn dry to the present low level through winter and higher during summer. These changes ensured the availability of water for irrigation and made the Murray Valley Australia's most productive agricultural region, but have seriously disrupted the life cycles of many ecosystems both inside and outside the river, and the irrigation has led to
dryland salinity that now threatens the agricultural industries.
The disruption of the river's natural flow, run-off from
agriculture, and the introduction of pest species like the
European Carp has led to serious environmental damage along the river's length and to concerns that the river will be unusably salty in the medium to long term — a serious problem given that the Murray supplies 40% of
Adelaide's domestic water. Efforts to alleviate the problems proceed but disagreement between interested groups stalls progress.
Further Information
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