126-604: A blackwater river is a type of river with a slow-moving channel flowing through forested swamps or wetlands . Most major blackwater rivers are in the Amazon Basin and the Southern United States . The term is used in fluvial studies, geology , geography , ecology , and biology . Not all dark rivers are blackwater in that technical sense. Some rivers in temperate regions, which drain or flow through areas of dark black loam , are simply black due to
252-582: A lake , an ocean , or another river. A stream refers to water that flows in a natural channel , a geographic feature that can contain flowing water. A stream may also be referred to as a watercourse. The study of the movement of water as it occurs on Earth is called hydrology , and their effect on the landscape is covered by geomorphology . Rivers are part of the water cycle , the continuous processes by which water moves about Earth. This means that all water that flows in rivers must ultimately come from precipitation . The sides of rivers have land that
378-547: A trip hammer , and grind grains with a millstone . In the Middle Ages , water mills began to automate many aspects of manual labor , and spread rapidly. By 1300, there were at least 10,000 mills in England alone. A medieval watermill could do the work of 30–60 human workers. Water mills were often used in conjunction with dams to focus and increase the speed of the water. Water wheels continued to be used up to and through
504-740: A boat along certain stretches. In these religions, such as that of the Altai in Russia , the river is considered a living being that must be afforded respect. Rivers are some of the most sacred places in Hinduism. There is archeological evidence that mass ritual bathing in rivers at least 5,000 years ago in the Indus river valley . While most rivers in India are revered, the Ganges is most sacred. The river has
630-514: A capacity of 20 people. There was also a cabin. The minister onboard, Rev. William Bussell, doubled as captain. On 16 August 1898, Etona arrived at Renmark , where the Bishop of Adelaide , Rev. Dr. John Harmer , held services the following Sunday with the assistance of Rev H M Wylie. In September of the same year, the service due in Holder on the 18th was suspended due to the vessel grounding on
756-515: A central role in various Hindu myths, and its water is said to have properties of healing as well as absolution from sins. Hindus believe that when the cremated remains of a person is released into the Ganges, their soul is released from the mortal world. Freshwater fish make up 40% of the world's fish species, but 20% of these species are known to have gone extinct in recent years. Human uses of rivers make these species especially vulnerable. Dams and other engineered changes to rivers can block
882-413: A common outlet. Rivers have a great effect on the landscape around them. They may regularly overflow their banks and flood the surrounding area, spreading nutrients to the surrounding area. Sediment or alluvium carried by rivers shapes the landscape around it, forming deltas and islands where the flow slows down. Rivers rarely run in a straight line, instead, they bend or meander ; the locations of
1008-408: A continuous flow of water throughout the year. This may be because an arid climate is too dry depending on the season to support a stream, or because a river is seasonally frozen in the winter (such as in an area with substantial permafrost ), or in the headwaters of rivers in mountains, where snowmelt is required to fuel the river. These rivers can appear in a variety of climates, and still provide
1134-564: A habitat for aquatic life and perform other ecological functions. Subterranean rivers may flow underground through flooded caves. This can happen in karst systems, where rock dissolves to form caves. These rivers provide a habitat for diverse microorganisms and have become an important target of study by microbiologists . Other rivers and streams have been covered over or converted to run in tunnels due to human development. These rivers do not typically host any life, and are often used only for stormwater or flood control. One such example
1260-495: A large scale. This has been attributed to unusually large floods destroying infrastructure; however, there is evidence that permanent changes to climate causing higher aridity and lower river flow may have been the determining factor in what river civilizations succeeded or dissolved. Water wheels began to be used at least 2,000 years ago to harness the energy of rivers. Water wheels turn an axle that can supply rotational energy to move water into aqueducts , work metal using
1386-527: A list of birds and mammals . George "Chinese" Morrison , then aged 18, navigated the river by canoe from Wodonga to its mouth, in 65 days, completing the 1,555-mile (2,503 km) journey in January 1881. Shipping cannot enter the Murray from the sea because it does not have an estuary . However, in the 19th century the river supported a substantial commercial trade using shallow-draft paddle steamers ,
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#17327830606261512-569: A low conductivity , similar to that of rainwater. Black and white waters differ in their planktonic fauna and flora. Tables 2 and 3 compare the number of planktonic animals caught in black and white water localities only a few meters apart. The black water was not as extreme an example as the Rio Negro system. However, it can be seen that the black water held greater numbers of rotifers but fewer crustaceans and mites . These crustaceans are important foods for larval fish . The zones where
1638-402: A number of both historic paddle steamers and newer boats offering cruises ranging from half an hour to five days. 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. The first bridge to cross the Murray, which was built in 1869, is in
1764-556: A peak in the 1970s, when between two or three dams were completed every day, and has since begun to decline. New dam projects are primarily focused in China , India , and other areas in Asia . The first civilizations of Earth were born on floodplains between 5,500 and 3,500 years ago. The freshwater, fertile soil, and transportation provided by rivers helped create the conditions for complex societies to emerge. Three such civilizations were
1890-891: A ritualistic sense has been compared to the Christian ritual of baptism , famously the Baptism of Jesus in the Jordan River . Floods also appear in Norse mythology , where the world is said to emerge from a void that eleven rivers flowed into. Aboriginal Australian religion and Mesoamerican mythology also have stories of floods, some of which contain no survivors, unlike the Abrahamic flood. Along with mythological rivers, religions have also cared for specific rivers as sacred rivers. The Ancient Celtic religion saw rivers as goddesses. The Nile had many gods attached to it. The tears of
2016-425: A river can take several forms. Tidal rivers (often part of an estuary ) have their levels rise and fall with the tide . Since the levels of these rivers are often already at or near sea level, the flow of alluvium and the brackish water that flows in these rivers may be either upriver or downriver depending on the time of day. Rivers that are not tidal may form deltas that continuously deposit alluvium into
2142-1026: A river's banks can change frequently. Rivers get their alluvium from erosion , which carves rock into canyons and valleys . Rivers have sustained human and animal life for millennia, including the first human civilizations . The organisms that live around or in a river such as fish , aquatic plants , and insects have different roles, including processing organic matter and predation . Rivers have produced abundant resources for humans, including food , transportation , drinking water , and recreation. Humans have engineered rivers to prevent flooding, irrigate crops, perform work with water wheels , and produce hydroelectricity from dams. People associate rivers with life and fertility and have strong religious, political, social, and mythological attachments to them. Rivers and river ecosystems are threatened by water pollution , climate change , and human activity. The construction of dams, canals , levees , and other engineered structures has eliminated habitats, has caused
2268-426: A sandbank. During its year of launch, the boiler of Etona gave way, being replaced at a cost of £87. 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
2394-460: A section of the river behind them into a lake or reservoir. This can provide nearby cities with a predictable supply of drinking water. Hydroelectricity is desirable as a form of renewable energy that does not require any inputs beyond the river itself. Dams are very common worldwide, with at least 75,000 higher than 6 feet (1.8 m) in the U.S. Globally, reservoirs created by dams cover 193,500 square miles (501,000 km ). Dam-building reached
2520-559: A series of barrages was built near the Murray Mouth to stop seawater entering the lower part of the river during low flow periods. They are the Goolwa Barrage, with a length of 632 metres (2,073 ft); Mundoo Channel Barragel 800 metres (2,600 ft); Boundary Creek Barragel 243 metres (797 ft); Ewe Island Barrage, 853 metres (2,799 ft); and Tauwitchere Barrage, 3.6 kilometres (2.2 mi). These dams inverted
2646-521: 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
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#17327830606262772-518: 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
2898-438: A water body is that body's riparian zone . Plants in the riparian zone of a river help stabilize its banks to prevent erosion and filter alluvium deposited by the river on the shore, including processing the nitrogen and other nutrients it contains. Forests in a riparian zone also provide important animal habitats . River ecosystems have also been categorized based on the variety of aquatic life they can sustain, also known as
3024-691: A water cycle that involved precipitation. The term flumen , in planetary geology , refers to channels on Saturn 's moon Titan that may carry liquid. Titan's rivers flow with liquid methane and ethane . There are river valleys that exhibit wave erosion , seas, and oceans. Scientists hope to study these systems to see how coasts erode without the influence of human activity, something that isn't possible when studying terrestrial rivers. Murray River The Murray River (in South Australia: River Murray ) ( Ngarrindjeri : Millewa , Yorta Yorta : Dhungala ( Tongala ))
3150-445: Is a tributary , and the place they meet is a confluence . Rivers must flow to lower altitudes due to gravity . The bed of a river is typically within a river valley between hills or mountains . Rivers flowing through an impermeable section of land such as rocks will erode the slopes on the sides of the river. When a river carves a plateau or a similar high-elevation area, a canyon can form, with cliffs on either side of
3276-612: Is a river in Southeastern 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 (the Murrumbidgee , Darling , Lachlan , Warrego and Paroo Rivers ). 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
3402-761: 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 . An additional reservoir was proposed in the 1960s at Chowilla Dam , which was to have been built in South Australia and would have flooded land mostly in Victoria and New South Wales. It was cancelled in favour of building Dartmouth Dam due to costs and concerns relating to increased salinity. From 1935 to 1940
3528-504: Is also important for the lumber industry , as logs can be shipped via river. Countries with dense forests and networks of rivers like Sweden have historically benefited the most from this method of trade. The rise of highways and the automobile has made this practice less common. One of the first large canals was the Canal du Midi , connecting rivers within France to create a path from
3654-564: Is an ancient dam built on the Nile 4,500 years ago. The Ancient Roman civilization used aqueducts to transport water to urban areas . Spanish Muslims used mills and water wheels beginning in the seventh century. Between 130 and 1492, larger dams were built in Japan, Afghanistan, and India, including 20 dams higher than 15 metres (49 ft). Canals began to be cut in Egypt as early as 3000 BC, and
3780-448: Is at a higher elevation than the river itself, and in these areas, water flows downhill into the river. The headwaters of a river are the smaller streams that feed a river, and make up the river's source. These streams may be small and flow rapidly down the sides of mountains . All of the land uphill of a river that feeds it with water in this way is in that river's drainage basin or watershed. A ridge of higher elevation land
3906-405: Is because any natural impediment to the flow of the river may cause the current to deflect in a different direction. When this happens, the alluvium carried by the river can build up against this impediment, redirecting the course of the river. The flow is then directed against the opposite bank of the river, which will erode into a more concave shape to accommodate the flow. The bank will still block
Blackwater river - Misplaced Pages Continue
4032-453: Is correlated with and thus can be used to predict certain data points related to rivers, such as the size of the drainage basin (drainage area), and the length of the channel. The ecosystem of a river includes the life that lives in its water, on its banks, and in the surrounding land. The width of the channel of a river, its velocity, and how shaded it is by nearby trees. Creatures in a river ecosystem may be divided into many roles based on
4158-497: Is in part because of a projected loss of snowpack in mountains, meaning that melting snow can't replenish rivers during warm summer months, leading to lower water levels. Lower-level rivers also have warmer temperatures, threatening species like salmon that prefer colder upstream temperatures. Attempts have been made to regulate the exploitation of rivers to preserve their ecological functions. Many wetland areas have become protected from development. Water restrictions can prevent
4284-589: Is known to have sold his share in the Bungaree Station , which he founded with his brothers, and relocated alongside the Murray at a site near Moorundie . In 1852, Francis Cadell , in preparation for the launch of his steamer service, explored the river in a canvas boat, travelling 1,300 miles (2,100 km) downstream from Swan Hill . In 1858, while acting as Minister of Land and Works for New South Wales, Irish nationalist and founder of Young Ireland , Charles Gavan Duffy , founded Carlyle Township on
4410-412: 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. Ngurunderi 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
4536-402: Is part of permafrost ice caps, or trace amounts of water vapor in the atmosphere. However, there is evidence that rivers flowed on Mars for at least 100,000 years. The Hellas Planitia is a crater left behind by an impact from an asteroid. It has sedimentary rock that was formed 3.7 billion years ago, and lava fields that are 3.3 billion years old. High resolution images of the surface of
4662-633: Is rarely static, the exact location of a river border may be called into question by countries. The Rio Grande between the United States and Mexico is regulated by the International Boundary and Water Commission to manage the right to fresh water from the river, as well as mark the exact location of the border. Up to 60% of fresh water used by countries comes from rivers that cross international borders. This can cause disputes between countries that live upstream and downstream of
4788-852: Is somewhat acidic (typical pH ~6.5) and very clear with a greenish color. The main Amazonian clearwater rivers have their source in the Brazilian Plateau (such as Tapajós , Tocantins , Xingu and some right tributaries of the Madeira ), but some originate in the Guiana Shield (such as Nhamundá , Paru , and Araguari ). Other rivers in Australia may experience infrequent 'blackwater events' associated with flood waters connecting to forested floodplains and these events may be associated with hypoxic waters [low oxygen]. Examples include
4914-701: Is that of the Mississippi River , whose drainage basin covers 40% of the contiguous United States . The river was then used for shipping crops from the American Midwest and cotton from the American South to other states as well as the Atlantic Ocean. The role of urban rivers has evolved from when they were a center of trade, food, and transportation to modern times when these uses are less necessary. Rivers remain central to
5040-553: Is the Sunswick Creek in New York City, which was covered in the 1800s and now exists only as a sewer-like pipe. While rivers may flow into lakes or man-made features such as reservoirs , the water they contain will always tend to flow down toward the ocean . However, if human activity siphons too much water away from a river for other uses, the riverbed may run dry before reaching the sea. The outlets mouth of
5166-553: Is the border between New South Wales and Victoria – specifically at the top of the bank of the Victorian side of the river. In a 1980 judgement, the High Court of Australia ruled on the question as to which state had jurisdiction in the unlawful death of a man who was fishing by the river's edge on the Victorian side of the river. This boundary definition can be ambiguous, since the river changes its course over time, and some of
Blackwater river - Misplaced Pages Continue
5292-488: Is the point at which the Murray River empties into the sea, and the interaction between its shallow, shifting and variable currents and the open sea can be complex and unpredictable. During the peak period of Murray River commerce (roughly 1855 to 1920), it presented a major impediment to the passage of goods and produce between Adelaide and the Murray settlements, and many vessels foundered or were wrecked there. Since
5418-842: Is what typically separates drainage basins; water on one side of a ridge will flow into one set of rivers, and water on the other side will flow into another. One example of this is the Continental Divide of the Americas in the Rocky Mountains . Water on the western side of the divide flows into the Pacific Ocean , whereas water on the other side flows into the Atlantic Ocean . Not all precipitation flows directly into rivers; some water seeps into underground aquifers . These, in turn, can still feed rivers via
5544-509: Is widely considered Australia's most important irrigated region. 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 . From an east–west direction it turns south at Morgan for its final 315 km (196 mi), reaching
5670-599: The 2024 Summer Olympics . Another example is the restoration of the Isar in Munich from being a fully canalized channel with hard embankments to being wider with naturally sloped banks and vegetation. This has improved wildlife habitat in the Isar, and provided more opportunities for recreation in the river. As a natural barrier , rivers are often used as a border between countries , cities, and other territories . For example,
5796-487: The Atlantic Ocean to the Mediterranean Sea . The nineteenth century saw canal-building become more common, with the U.S. building 4,400 miles (7,100 km) of canals by 1830. Rivers began to be used by cargo ships at a larger scale, and these canals were used in conjunction with river engineering projects like dredging and straightening to ensure the efficient flow of goods. One of the largest such projects
5922-501: The Industrial Revolution as a source of power for textile mills and other factories, but were eventually supplanted by steam power . Rivers became more industrialized with the growth of technology and the human population . As fish and water could be brought from elsewhere, and goods and people could be transported via railways , pre-industrial river uses diminished in favor of more complex uses. This meant that
6048-791: The Lamari River in New Guinea separates the Angu and the Fore people in New Guinea. The two cultures speak different languages and rarely mix. 23% of international borders are large rivers (defined as those over 30 meters wide). The traditional northern border of the Roman Empire was the Danube , a river that today forms the border of Hungary and Slovakia . Since the flow of a river
6174-499: The Murray River , Edward River , Wakool River and Murrumbidgee River . River#Classification A river is a natural freshwater stream that flows on land or inside caves towards another body of water at a lower elevation , such as an ocean , lake , or another river. A river may run dry before reaching the end of its course if it runs out of water, or only flow during certain seasons. Rivers are regulated by
6300-525: The Nile and the Ganges . The Quran describes these four rivers as flowing with water, milk, wine, and honey, respectively. The book of Genesis also contains a story of a great flood . Similar myths are present in the Epic of Gilgamesh , Sumerian mythology, and in other cultures. In Genesis, the flood's role was to cleanse Earth of the wrongdoing of humanity. The act of water working to cleanse humans in
6426-568: The River Continuum Concept . "Shredders" are organisms that consume this organic material. The role of a "grazer" or "scraper" organism is to feed on the algae that collects on rocks and plants. "Collectors" consume the detritus of dead organisms. Lastly, predators feed on living things to survive. The river can then be modeled by the availability of resources for each creature's role. A shady area with deciduous trees might experience frequent deposits of organic matter in
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#17327830606266552-627: The River Lethe to forget their previous life. Rivers also appear in descriptions of paradise in Abrahamic religions , beginning with the story of Genesis . A river beginning in the Garden of Eden waters the garden and then splits into four rivers that flow to provide water to the world. These rivers include the Tigris and Euphrates , and two rivers that are possibly apocryphal but may refer to
6678-787: The Sumerians in the Tigris–Euphrates river system , the Ancient Egyptian civilization in the Nile, and the Indus Valley Civilization on the Indus River . The desert climates of the surrounding areas made these societies especially reliant on rivers for survival, leading to people clustering in these areas to form the first cities . It is also thought that these civilizations were the first to organize
6804-485: The climate . The alluvium carried by rivers, laden with minerals, is deposited into the floodplain when the banks spill over, providing new nutrients to the soil, allowing them to support human activity like farming as well as a host of plant and animal life. Deposited sediment from rivers can form temporary or long-lasting fluvial islands . These islands exist in almost every river. About half of all waterways on Earth are intermittent rivers , which do not always have
6930-685: The cultural identity of cities and nations. Famous examples include the River Thames 's relationship to London , the Seine to Paris , and the Hudson River to New York City . The restoration of water quality and recreation to urban rivers has been a goal of modern administrations. For example, swimming was banned in the Seine for over 100 years due to concerns about pollution and the spread of E. coli , until cleanup efforts to allow its use in
7056-484: The discharge of a river, the amount of water passing through it at a particular time. The flow of a river can act as a means of transportation for plant and animal species, as well as a barrier. For example, the Amazon River is so wide in parts that the variety of species on either side of its basin are distinct. Some fish may swim upstream to spawn as part of a seasonal migration . Species that travel from
7182-465: The extinction of some species, and lowered the amount of alluvium flowing through rivers. Decreased snowfall from climate change has resulted in less water available for rivers during the summer. Regulation of pollution, dam removal , and sewage treatment have helped to improve water quality and restore river habitats. A river is a natural flow of freshwater that flows on or through land towards another body of water downhill. This flow can be into
7308-401: The river banks have been modified. For 11 km (6.8 mi) west of the line of longitude 141°E, the border is between Victoria and South Australia, in the middle of the river. The discrepancy was caused during the 1840s, when the border was originally surveyed, by an east–west miscalculation of 3.72 kilometres (2.31 miles). West of this sector, the Murray is entirely within
7434-517: The river red gum . 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. The Murray has also flooded on occasion. The most significant was the flood of 1956 : lasting for up to six months, it inundated many towns on its lower reaches in South Australia. Between 2.5 and 0.5 million years ago,
7560-436: The sea . The sediment yield of a river is the quantity of sand per unit area within a watershed that is removed over a period of time. The monitoring of the sediment yield of a river is important for ecologists to understand the health of its ecosystems, the rate of erosion of the river's environment, and the effects of human activity. Rivers rarely run in a straight direction, instead preferring to bend or meander . This
7686-475: The water cycle , the processes by which water moves around the Earth. Water first enters rivers through precipitation , whether from rainfall, the runoff of water down a slope, the melting of glaciers or snow , or seepage from aquifers beneath the surface of the Earth. Rivers flow in channeled watercourses and merge in confluences to form drainage basins , areas where surface water eventually flows to
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#17327830606267812-521: The water table , the groundwater beneath the surface of the land stored in the soil . Water flows into rivers in places where the river's elevation is lower than that of the water table. This phenomenon is why rivers can still flow even during times of drought . Rivers are also fed by the melting of snow glaciers present in higher elevation regions. In summer months, higher temperatures melt snow and ice, causing additional water to flow into rivers. Glacier melt can supplement snow melt in times like
7938-467: The Cadell Fault. About 25,000 years ago, displacement occurred along this fault, raising its eastern edge, which runs north–south, 8 to 12 m (26 to 39 ft) above the floodplain. This created a complex series of events. A section of the original Murray River channel immediately behind the fault was rendered abandoned (it exists today as an empty channel known as Green Gully). The Goulburn River
8064-500: The Murray River, after his close friend, Scottish historian and essayist Thomas Carlyle . Included in the township were "Jane Street", named in honour of Carlyle's wife Jane Carlyle and "Stuart-Mill Street" in honour of political philosopher John Stuart Mill In 1858, the Government Zoologist , William Blandowski , together with Gerard Krefft , explored the lower reaches of the Murray and Darling rivers, compiling
8190-422: The Murray and its tributaries by destroying aquatic plants and permanently raising turbidity . Carp is the most common species, and can be found in all segments of the river. Four large reservoirs were built along the Murray. In addition to Lake Victoria (completed late 1920s), these are Lake Hume near Albury-Wodonga (completed 1936), Lake Mulwala at Yarrawonga (completed 1939), and Lake Dartmouth , which
8316-458: 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. Roonka Flat , near Blanchetown , was a site of occupation since at least 7000BC. The first Europeans to encounter the river were Hamilton Hume and William Hovell , who crossed
8442-466: The Murray short-necked turtle, broad-clawed yabbies and the large-clawed Macrobrachium shrimp, in addition to aquatic species more widely distributed through Southeastern Australia such as common long-necked turtles, common yabbies , the small claw-less paratya shrimp, water rats and platypus . The Murray crayfish , an endangered species, was able to increase its numbers thanks to scientists. The Murray also supports fringeing corridors and forests of
8568-480: The Murray terminated in a vast freshwater lake – Lake Bungunnia – formed by earth movements that blocked the river near Swan Reach . At its maximum extent, Lake Bungunnia covered 33,000 km (12,741 sq mi), extending to near the Menindee Lakes in the north and to near Boundary Bend in the south. The draining of Lake Bungunnia occurred approximately 600,000 years ago. Deep clays deposited by
8694-524: The Red Gum forests, actually travels through the Edward River channel. The Murray has not had enough flow power to naturally enlarge The Barmah Choke and The Narrows to increase the amount of water they can carry. 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. The Murray Mouth
8820-491: The advent of large-scale river regulation , the waters at the Murray Mouth are almost invariably slow and shallow. As of 2010 , the Murray River system received 58 per cent of its natural flow; the figure varies considerably. The border between Victoria and New South Wales (NSW) lies along the top of the southern or left bank of the Murray River. The Murray forms part of the 3,750 km (2,330 mi) long combined Murray–Darling river system that drains most of
8946-433: 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 led directly to the formation of the famous Barmah River Red Gum Forests. The Barmah Choke and The Narrows restrict the amount of water that can travel down this part of the Murray. In times of flood and high irrigation flows the majority of the water, in addition to flooding
9072-695: The bodies of humans and animals worldwide, as well as in the soil, with potentially negative health effects. Research into how to remove it from the environment, and how harmful exposure is, is ongoing. Fertilizer from farms can lead to a proliferation of algae on the surface of rivers and oceans, which prevents oxygen and light from dissolving into water, making it impossible for underwater life to survive in these so-called dead zones . Urban rivers are typically surrounded by impermeable surfaces like stone, asphalt , and concrete. Cities often have storm drains that direct this water to rivers. This can cause flooding risk as large amounts of water are directed into
9198-478: The color of the soil; these rivers are black mud rivers . There are also black mud estuaries . Blackwater rivers are lower in nutrients than whitewater rivers and have ionic concentrations higher than rainwater. The unique conditions lead to flora and fauna that differ from both whitewater and clearwater rivers . The classification of Amazonian rivers into black, clear, and whitewater was first proposed by Alfred Russel Wallace in 1853 based on water colour, but
9324-405: The complete draining of rivers. Limits on the construction of dams, as well as dam removal , can restore the natural habitats of river species. Regulators can also ensure regular releases of water from dams to keep animal habitats supplied with water. Limits on pollutants like pesticides can help improve water quality. Today, the surface of Mars does not have liquid water. All water on Mars
9450-581: The driest continents on Earth, the Murray has significant cultural relevance to Aboriginal Australians . According to the people 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,
9576-546: The early 2000s, dredging machines have operated at the Murray Mouth 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. Without the dredging, the mouth would silt up and close, cutting the supply of fresh sea-water into the Coorong National Park, which would then warm up, stagnate and die. Being one of the major river systems on one of
9702-707: The eastern edge of Lake Alexandrina , which fluctuates in salinity . The water then flows through several channels around Hindmarsh Island and Mundoo Island . There it is joined by lagoon water from The Coorong to the south-east before emptying into the Great Australian Bight (often referenced on Australian maps as the Southern Ocean ) through the Murray Mouth , 10 km (6.2 mi) east of Goolwa South . Despite discharging considerable volumes of water at times, particularly before
9828-436: The effect of normalizing the effects of rivers; the greatest floods are smaller and more predictable, and larger sections are open for navigation by boats and other watercraft. A major effect of river engineering has been a reduced sediment output of large rivers. For example, the Mississippi River produced 400 million tons of sediment per year. Due to the construction of reservoirs , sediment buildup in man-made levees , and
9954-499: The first trips being made by two boats from South Australia on the spring flood of 1853. The Lady Augusta , captained by Francis Cadell , reached Swan Hill while another, Mary Ann , captained by William Randell , reached 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 , Wahgunyah and Albury. The arrival of steamboat transport
10080-451: The fish zonation concept. Smaller rivers can only sustain smaller fish that can comfortably fit in its waters, whereas larger rivers can contain both small fish and large fish. This means that larger rivers can host a larger variety of species. This is analogous to the species-area relationship , the concept of larger habitats being host to more species. In this case, it is known as the species-discharge relationship, referring specifically to
10206-673: The floating of wood on rivers to transport it, was especially important. Rivers also were an important source of drinking water . For civilizations built around rivers, fish were an important part of the diet of humans. Some rivers supported fishing activities, but were ill-suited to farming, such as those in the Pacific Northwest . Other animals that live in or near rivers like frogs , mussels , and beavers could provide food and valuable goods such as fur . Humans have been building infrastructure to use rivers for thousands of years. The Sadd el-Kafara dam near Cairo , Egypt,
10332-412: The flow of the river beneath its surface. These help rivers flow straighter by increasing the speed of the water at the middle of the channel, helping to control floods. Levees are also used for this purpose. They can be thought of as dams constructed on the sides of rivers, meant to hold back water from flooding the surrounding area during periods of high rainfall. They are often constructed by building up
10458-399: The flow, causing it to reflect in the other direction. Thus, a bend in the river is created. Rivers may run through low, flat regions on their way to the sea. These places may have floodplains that are periodically flooded when there is a high level of water running through the river. These events may be referred to as "wet seasons' and "dry seasons" when the flooding is predictable due to
10584-650: The form of leaves. In this type of ecosystem, collectors and shredders will be most active. As the river becomes deeper and wider, it may move slower and receive more sunlight . This supports invertebrates and a variety of fish , as well as scrapers feeding on algae. Further downstream, the river may get most of its energy from organic matter that was already processed upstream by collectors and shredders. Predators may be more active here, including fish that feed on plants, plankton , and other fish. The flood pulse concept focuses on habitats that flood seasonally, including lakes and marshes . The land that interfaces with
10710-508: The goddess Isis were said to be the cause of the river's yearly flooding, itself personified by the goddess Hapi . Many African religions regard certain rivers as the originator of life. In Yoruba religion , Yemọja rules over the Ogun River in modern-day Nigeria and is responsible for creating all children and fish. Some sacred rivers have religious prohibitions attached to them, such as not being allowed to drink from them or ride in
10836-419: The inland of Victoria, New South Wales and the southern part of Queensland. 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. More often, a sandbar formed at the mouth and stopped the flow. The Murray
10962-491: 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 riverborne transport was already declining due to improved highway and railway systems. The disruption of the river's natural flow, run-off from agriculture, and the introduction of pest species such as the European carp has led to serious environmental damage along
11088-553: The irrigation has led to dryland salinity that now threatens the agricultural industries. In 2006, the Government of South Australia released a plan to investigate the construction of controversial Wellington Weir . Lock 1 was completed near Blanchetown in 1922. Torrumbarry weir downstream of Echuca began operating in December 1923. Of the several locks that were proposed, only thirteen were completed; Locks 1 to 11 on
11214-428: The irrigation of desert environments for growing food. Growing food at scale allowed people to specialize in other roles, form hierarchies, and organize themselves in new ways, leading to the birth of civilization. In pre-industrial society , rivers were a source of transportation and abundant resources. Many civilizations depended on what resources were local to them to survive. Shipping of commodities, especially
11340-663: 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 Bungunnia appears to have marked 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 Bungunnia; today Neoceratodus lungfish are only found in several Queensland rivers. The noted Barmah River red gum forests owe their existence to
11466-434: The late summer, when there may be less snow left to melt, helping to ensure that the rivers downstream of the glaciers have a continuous supply of water. Rivers flow downhill, with their direction determined by gravity . A common misconception holds that all or most rivers flow from North to South, but this is not true. As rivers flow downstream, they eventually merge to form larger rivers. A river that feeds into another
11592-474: The level of river branching in a drainage basin. Several systems of stream order exist, one of which is the Strahler number . In this system, the first tributaries of a river are 1st order rivers. When two 1st order rivers merge, the resulting river is 2nd order. If a river of a higher order and a lower order merge, the order is incremented from whichever of the previous rivers had the higher order. Stream order
11718-561: The local ecosystems of rivers needed less protection as humans became less reliant on them for their continued flourishing. River engineering began to develop projects that enabled industrial hydropower , canals for the more efficient movement of goods, as well as projects for flood prevention . River transportation has historically been significantly cheaper and faster than transportation by land. Rivers helped fuel urbanization as goods such as grain and fuel could be floated downriver to supply cities with resources. River transportation
11844-407: The mechanical shadoof began to be used to raise the elevation of water. Drought years harmed crop yields, and leaders of society were incentivized to ensure regular water and food availability to remain in power. Engineering projects like the shadoof and canals could help prevent these crises. Despite this, there is evidence that floodplain-based civilizations may have been abandoned occasionally at
11970-400: The migration routes of fish and destroy habitats. Rivers that flow freely from headwaters to the sea have better water quality, and also retain their ability to transport nutrient-rich alluvium and other organic material downstream, keeping the ecosystem healthy. The creation of a lake changes the habitat of that portion of water, and blocks the transportation of sediment, as well as preventing
12096-418: The more neutral white waters. The major difference is the concentrations of sodium , magnesium , calcium , and potassium ; these are very low in black waters. This has ecological implications. Some animals need more calcium than is available in blackwaters, so for example, snails , which need much calcium to build shells, are not abundant in blackwaters. The lack of dissolved ions in black waters results in
12222-399: The natural meandering of the river. Dams block the migration of fish such as salmon for which fish ladder and other bypass systems have been attempted, but these are not always effective. Pollution from factories and urban areas can also damage water quality. " Per- and polyfluoroalkyl substances (PFAS) is a widely used chemical that breaks down at a slow rate. It has been found in
12348-429: The natural terrain with soil or clay. Some levees are supplemented with floodways, channels used to redirect floodwater away from farms and populated areas. Dams restrict the flow of water through a river. They can be built for navigational purposes, providing a higher level of water upstream for boats to travel in. They may also be used for hydroelectricity , or power generation from rivers. Dams typically transform
12474-484: 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
12600-425: The plain show evidence of a river network, and even river deltas. These images reveal channels formed in the rock, recognized by geologists who study rivers on Earth as being formed by rivers, as well as "bench and slope" landforms, outcroppings of rock that show evidence of river erosion. Not only do these formations suggest that rivers once existed, but that they flowed for extensive time periods, and were part of
12726-518: The remaining length of the Murray to finally reach Lake Alexandrina and the river's mouth. The vicinity of the Murray Mouth was explored more thoroughly by Captain Collet Barker in 1831. The first three settlers on the Murray River are known to have been James Collins Hawker (explorer and surveyor) along with Edward John Eyre (explorer and later Governor of Jamaica ) plus E.B. Scott (onetime superintendent of Yatala Labour Prison ). Hawker
12852-448: The removal of natural banks replaced with revetments , this sediment output has been reduced by 60%. The most basic river projects involve the clearing of obstructions like fallen trees. This can scale up to dredging , the excavation of sediment buildup in a channel, to provide a deeper area for navigation. These activities require regular maintenance as the location of the river banks changes over time, floods bring foreign objects into
12978-536: The reverse, death and destruction, especially through floods . This power has caused rivers to have a central role in religion , ritual , and mythology . In Greek mythology , the underworld is bordered by several rivers. Ancient Greeks believed that the souls of those who perished had to be borne across the River Styx on a boat by Charon in exchange for money. Souls that were judged to be good were admitted to Elysium and permitted to drink water from
13104-426: The river channel is unusually narrow), before entering into the proper Murray River channel again. The primary result of the Cadell Fault – that the west-flowing water of the Murray River strikes the north-south fault and diverts both north and south around the fault in the two main channels (Edward and ancestral Goulburn) in addition to a fan of small streams, and regularly floods a large amount of low-lying country in
13230-645: 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
13356-696: 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
13482-595: The river's length. There are widespread concerns that the river will be unusably salty in the medium to long term – a serious problem given that the Murray supplies 40 per cent of the water supply for Adelaide . Efforts to alleviate the problems have proceeded but disagreement between various groups has hampered progress. Introduced fish species such as carp , gambusia , weather loach , redfin perch , brown trout , and rainbow trout have also had serious negative effects on native fish. The most pernicious are carp, which have contributed to environmental degradation of
13608-468: The river, and natural sediment buildup continues. Artificial channels are often constructed to "cut off" winding sections of a river with a shorter path, or to direct the flow of a river in a straighter direction. This effect, known as channelization, has made the distance required to traverse the Missouri River in 116 kilometres (72 mi) shorter. Dikes are channels built perpendicular to
13734-552: The river. Areas of a river with softer rock weather faster than areas with harder rock, causing a difference in elevation between two points of a river. This can cause the formation of a waterfall as the river's flow falls down a vertical drop. A river in a permeable area does not exhibit this behavior and may even have raised banks due to sediment. Rivers also change their landscape through their transportation of sediment , often known as alluvium when applied specifically to rivers. This debris comes from erosion performed by
13860-625: The river. A country that is downstream of another may object to the upstream country diverting too much water for agricultural uses, pollution, as well as the creation of dams that change the river's flow characteristics. For example, Egypt has an agreement with Sudan requiring a specific minimum volume of water to pass into the Nile yearly over the Aswan Dam , to maintain both countries access to water. The importance of rivers throughout human history has given them an association with life and fertility . They have also become associated with
13986-533: 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 the snags. Author E.J. Brady chronicled an eventful journey downriver in a small motor boat from Albury to the coast in 1911 in River Rovers. 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
14112-457: The rivers themselves, debris swept into rivers by rainfall, as well as erosion caused by the slow movement of glaciers. The sand in deserts and the sediment that forms bar islands is from rivers. The particle size of the debris is gradually sorted by the river, with heavier particles like rocks sinking to the bottom, and finer particles like sand or silt carried further downriver . This sediment may be deposited in river valleys or carried to
14238-412: The rivers. Due to these impermeable surfaces, these rivers often have very little alluvium carried in them, causing more erosion once the river exits the impermeable area. It has historically been common for sewage to be directed directly to rivers via sewer systems without being treated, along with pollution from industry. This has resulted in a loss of animal and plant life in urban rivers, as well as
14364-409: The sea from their mouths. Depending on the activity of waves, the strength of the river, and the strength of the tidal current, the sediment can accumulate to form new land. When viewed from above, a delta can appear to take the form of several triangular shapes as the river mouth appears to fan out from the original coastline . In hydrology , a stream order is a positive integer used to describe
14490-414: The sea to breed in freshwater rivers are anadromous. Salmon are an anadromous fish that may die in the river after spawning, contributing nutrients back to the river ecosystem. Modern river engineering involves a large-scale collection of independent river engineering structures that have the goal of flood control , improved navigation, recreation, and ecosystem management. Many of these projects have
14616-519: The spread of waterborne diseases such as cholera . In modern times, sewage treatment and controls on pollution from factories have improved the water quality of urban rivers. Climate change can change the flooding cycles and water supply available to rivers. Floods can be larger and more destructive than expected, causing damage to the surrounding areas. Floods can also wash unhealthy chemicals and sediment into rivers. Droughts can be deeper and longer, causing rivers to run dangerously low. This
14742-578: The state of South Australia. Major settlements along the course of the river, from its source to the Southern Ocean, and their populations from the 2016 Australian census are as follows. The Murray and its tributaries support a variety of river life adapted to its vagaries. This includes 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
14868-434: 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 (62 mi) long lock pool that aided irrigation pumping from Mildura and Red Cliffs . Each lock has a navigable passage next to it through
14994-524: The town of Murray Bridge, formerly called Edwards Crossing. To distinguish this bridge from the many others that span the Murray River, this bridge is known as Murray River road bridge, Murray Bridge Tolls applied on South Australian ferries until abolished in November 1961. Small-scale pumping plants began drawing water from the Murray in the 1850s and the first high-volume plant was constructed at Mildura in 1887. The introduction of pumping stations along
15120-472: The two waters mix are attractive to ostracods and young fish. These mixing zones tend to have many animals. The abundance is shown in Table 3, which compares animals in 10 litres (2.2 imp gal; 2.6 US gal) of water. Blackwater rivers resemble clearwater rivers in having a low conductivity and relatively low levels of dissolved solids , but clearwater rivers have water that often only
15246-536: The types were more clearly defined by chemistry and physics by Harald Sioli [ de ] from the 1950s to the 1980s. Although many Amazonian rivers fall clearly into one of these categories, others show a mix of characteristics and may vary depending on season and flood levels. Black and white waters differ significantly in their ionic composition, as shown in Table 1 . Black waters are more acidic , resulting in an aluminum concentration greater than that of
15372-409: The weir, which is opened during periods of high river flow, when there is 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
15498-400: The 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 said to be the remnants of his rafts; they are known as Lalangengall or the two watercraft . This story of a hunter pursuing a Murray cod that carved out
15624-610: 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's waters still flow. Then the natural dam on the Goulburn River failed, the lake drained, and the Murray changed its course to the south and started to flow through the smaller Goulburn River channel, creating "The Barmah Choke" and "The Narrows" (where
15750-428: Was launched as a mission steamer, replacing an earlier steam launch, also named Etona , which had been operating on the Murray since 1891. The vessel was based at Murray Bridge , and operated between Goolwa and the Victorian border, stopping at towns such as Mannum , Morgan and Renmark as well as isolated settlements and workcamps. The forepart of the vessel was used a chapel fitted with an altar and organ, with
15876-460: 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 steam paddleship Etona
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