Murray River

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Lore & Background

The Murray rises in the Australian Alps, draining the western side of Australia's highest mountains, then meanders northwest across Australia's inland plains, forming the border between the states of New South Wales and Victoria as it flows into South Australia. The border lies along the top of the southern or left bank of the Murray River, meaning the entire river—including the water and the riverbed—falls entirely within New South Wales until it enters South Australia. From an east–west direction it turns south at Morgan for its final 315 km (196 mi), reaching the eastern edge of Lake Alexandrina. The water then flows through several channels around Hindmarsh Island and Mundoo Island, joined by lagoon water from The Coorong before emptying into Encounter Bay through the Murray Mouth, 10 km (6.2 mi) east of Goolwa South. As of 2010, the Murray River system received just 58 per cent of its natural flow, though this figure varies considerably. The Murray carries only a small fraction of the water of comparably sized rivers in other parts of the world, and with great annual variability of its flow. It has dried up completely during extreme droughts on three occasions since official record-keeping began. The Murray and its tributaries support native fish such as the famous Murray cod, trout cod, golden perch, Macquarie perch, silver perch, eel-tailed catfish, Australian smelt and western carp gudgeon, as well as other aquatic species such as the Murray short-necked turtle, broad-clawed yabbies, water rats and platypus. The health of the Murray has declined significantly since European settlement, particularly through regulation of its flows. Extreme droughts between 2000 and 2007 put significant stress on river red gum forests, leading to mounting concern over their long-term survival. Ancient history includes Lake Bungunnia, a vast freshwater lake that existed between 2.5 and 0.5 million years ago, covering 33,000 km² (12,741 sq mi). The draining of Lake Bungunnia occurred approximately 600,000 years ago. About 25,000 years ago, displacement occurred along the Cadell Fault, raising its eastern edge 8 to 12 m (26 to 39 ft) above the floodplain. This created a complex series of events that led to the formation of the famous Barmah river red gum forests. The Murray Mouth has been dredged since the early 2000s, with machines operating for 24 hours a day moving sand from the channel to maintain a minimal flow from the sea and into the Coorong's lagoon system.

Reader's Guide

The Murray River is central to Australia's geography, economy, and ecology. As the longest river in Australia, spanning 2,508 km (1,558 mi), it forms the backbone of the Murray–Darling basin, which covers about one-seventh of the continent and is widely considered Australia's most important irrigated region. Its waters support agriculture, settlements, and unique ecosystems, including the iconic river red gum forests and native fish like the famous Murray cod. The river's flow has been heavily regulated, with only 58% of its natural flow remaining as of 2010, leading to ecological decline and concerns over the survival of forests during extreme droughts between 2000 and 2007. The river also has a complex legal role, defining the border between New South Wales and Victoria along the top of the southern bank, a boundary that was subject to a 1980 High Court of Australia judgement regarding jurisdiction in the unlawful death of a man fishing on the Victorian side. The Murray Mouth has historically been a major impediment to commerce between roughly 1855 and 1920, and dredging has been required since the early 2000s to keep it open. The river's ancient past includes Lake Bungunnia, which covered 33,000 km² between 2.5 and 0.5 million years ago, and the Cadell Fault displacement about 25,000 years ago that shaped the current landscape and led to the formation of the Barmah river red gum forests. The Murray remains a vital resource, facing challenges of water management, drought, and environmental sustainability.

Did You Know?

• The Murray River has dried up completely during extreme droughts on three occasions since official record-keeping began.
• The border between Victoria and New South Wales lies along the top of the southern bank of the Murray River, meaning the entire river and riverbed falls within New South Wales until it enters South Australia.
• Between 2.5 and 0.5 million years ago, the Murray terminated in a vast freshwater lake called Lake Bungunnia, which covered 33,000 km².
• About 25,000 years ago, displacement along the Cadell Fault raised its eastern edge 8 to 12 m above the floodplain, leading to the formation of the Barmah river red gum forests.
• Since the early 2000s, dredging machines have operated at the Murray Mouth for 24 hours a day to prevent the mouth from silting up and closing.

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