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30-417: The Lake Machattie Area is a 909 km tract of land comprising Lakes Machattie, Mipia and Koolivoo, with the surrounding Georgina River and Eyre Creek floodplains , in the arid Channel Country of western Queensland , Australia . The area is important as a breeding site for waterbirds . The floodplains are seasonally flooded and contain several freshwater lakes which continue to hold water well after

60-597: A tripoint . Various examples are found in the list below. A number of major cities, such as Chongqing , St. Louis , and Khartoum , arose at confluences; further examples appear in the list. Within a city, a confluence often forms a visually prominent point, so that confluences are sometimes chosen as the site of prominent public buildings or monuments, as in Koblenz , Lyon , and Winnipeg . Cities also often build parks at confluences, sometimes as projects of municipal improvement, as at Portland and Pittsburgh . In other cases,

90-414: A confluence can be divided into six distinct features which are commonly called confluence flow zones (CFZ). These include The broader field of engineering encompasses a vast assortment of subjects which concern confluences. In hydraulic civil engineering , where two or more underground culverted / artificially buried watercourses intersect, great attention should be paid to the hydrodynamic aspects of

120-619: A confluence is an industrial site, as in Philadelphia or Mannheim . Often a confluence lies in the shared floodplain of the two rivers and nothing is built on it, for example at Manaus , described below. One other way that confluences may be exploited by humans is as sacred places in religions . Rogers suggests that for the ancient peoples of the Iron Age in northwest Europe, watery locations were often sacred, especially sources and confluences. Pre-Christian Slavic peoples chose confluences as

150-482: A corresponding shift in habitat characteristics." Another science relevant to the study of confluences is chemistry , because sometimes the mixing of the waters of two streams triggers a chemical reaction, particularly in a polluted stream. The United States Geological Survey gives an example: "chemical changes occur when a stream contaminated with acid mine drainage combines with a stream with near-neutral pH water; these reactions happen very rapidly and influence

180-575: A small part of the Macdonnell Ranges drains into the Georgina, most of the catchment is a flat as the Diamantina , though low ranges are very prominent in the north-west of the basin. This western part of the basin has sandy soils that are too infertile to provide nutritious fodder for cattle or sheep and a large proportion is an Aboriginal reserve . The eastern part of the Georgina catchment near Boulia

210-443: A variety of sciences. Hydrology studies the characteristic flow patterns of confluences and how they give rise to patterns of erosion, bars, and scour pools. The water flows and their consequences are often studied with mathematical models . Confluences are relevant to the distribution of living organisms (i.e., ecology ) as well; "the general pattern [downstream of confluences] of increasing stream flow and decreasing slopes drives

240-717: Is 168 mm. The site has been identified by BirdLife International as an Important Bird Area (IBA) because it has supported over 300,000 waterbirds, including over 1% of the world populations of freckled and pink-eared ducks , Australian pelicans , straw-necked ibises , royal spoonbills , little black cormorants , red-necked avocets and sharp-tailed sandpipers . It also supports Australian bustards and grey grasswrens . Large numbers of Australian pratincoles , black-tailed godwits and flock bronzewings have been recorded. 24°49′25″S 139°33′52″E  /  24.82361°S 139.56444°E  / -24.82361; 139.56444 This Queensland location article

270-578: Is 417 metres (1,368 ft) long and is accompanied by a 5.6-kilometre (3.5 mi) highway deviation west from Camooweal. The bridge uses an unusual arch design to avoid placing pylons into the river bed which is culturally significant to the local Dugalunji people, who call the new bridge Ilaga Thuwani meaning The Camping Ground of the Rainbow Serpent . 23°30′S 139°47′E  /  23.500°S 139.783°E  / -23.500; 139.783 Confluence Confluences are studied in

300-635: Is a stub . You can help Misplaced Pages by expanding it . Georgina River The Georgina River is the north-westernmost of the three major rivers of the Channel Country in Central West Queensland , that also flows through a portion of the Northern Territory , in central Australia . Part of the Lake Eyre basin , the Georgina flows in extremely wet years into Lake Eyre . The river

330-675: Is named in honour of Georgina Mildred Kennedy, the daughter of Queensland governor Arthur Kennedy . The river was originally called the Herbert River before being given its current name in 1890 to avoid confusion with the other river in Queensland that bears that name. With its headwaters rising in the Barkly Tableland , north of Camooweal in Queensland, and in the extreme east of the Northern Territory beyond Tennant Creek and to

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360-471: Is only about 0.7 km (570,000 acre⋅ft). There is such extreme variation that — although streamgauging records are too poor to prove it conclusively — meteorological records leave no doubt that there have been many years of zero runoff in the entire basin (1905, 1928 and 1961 would without doubt fit into this category), whilst in very wet years such as 1974, 1977 and 2000, runoff can be as high as 6.28 km (5,090,000 acre⋅ft) or more. Although

390-735: Is used to describe the meeting of tidal or other non-riverine bodies of water, such as two canals or a canal and a lake. A one-mile (1.6 km) portion of the Industrial Canal in New Orleans accommodates the Gulf Intracoastal Waterway and the Mississippi River-Gulf Outlet Canal ; therefore those three waterways are confluent there. The term confluence can also apply to the process of merging or flowing together of other substance. For example, it may refer to

420-589: Is very similar to the Diamantina and Cooper basins, being grassy plains with heavy cracking clay soils that are quite fertile and provide very good feed in wet years for livestock. The Lake Machattie Area is an important breeding site for waterbirds. Climatically, the Georgina catchment tends to be somewhat drier than the Diamantina or Cooper, with average annual rainfall ranging from around 400 millimetres (16 in) north of Camooweal to around 225 millimetres (8.9 in) at Bedourie . Extremely dry years can give

450-702: The Barkly Highway (the only sealed road between Queensland and the Northern Territory), a longstanding problem was the flooding of the Georgina River immediately west of Camooweal in Queensland. As the water levels in the Georgina River vary enormously from being completely dry to flooding, the Barkly Highway bridge over the Georgina River was often unusable for many days due to flooding, with road trains and other heavy vehicles having to wait weeks before it

480-567: The Georgina flows south into the Channel Country, it reaches a confluence with Eyre Creek that, in times of peak flow, empties into the Warburton River and ultimately into Lake Eyre. The basin of the Georgina totals around 232,000 square kilometres (90,000 sq mi), or about the same size as the Australian state of Victoria . Because it is so arid, however, its mean annual flow

510-462: The River rising over 23 feet (7 m), the highest level in over 36 years. The lower reaches flooded in 1950 and again in 1953 following heavy rain events further north. The 1953 flood was 6 inches (152 mm) higher at Glengyle Station compared to the 1950 event. The Diamantina River was also in flood and the waters were expected to make it to Lake Eyre . Moderate flooding was experienced along

540-472: The catchment can receive as much as 350 millimetres (14 in) in a month or 150 millimetres (5.9 in) in a day or two. Temperatures are generally hot, with most areas having maxima of over 30 °C (86 °F) on over 225 days per year. Frosts are rare but have been reported on occasions in all areas of the basin – however even in June and July maxima are around 25 °C (77 °F). During severe floods

570-573: The course of a month. The Georgina River and the Diamatina Rivers both were flooded and the Sandringham station was submerged. The upper watershed in the Northern Territory were subjected to severe flooding in 1901 when Lake Nash Station experienced over 10 inches (254 mm) of rain in a single day, with the Georgina River running at almost record high levels. The surrounding areas received over 4 inches (102 mm) of rain in 1953 resulting in

600-410: The entire basin less than 100 millimetres (3.9 in) whilst in 1974, 1977 and 2000 many areas had over 800 millimetres (31 in) and some as much as 1,000 millimetres (39 in). Almost all of this rain falls in the summer, and it is quite normal for the period from May to September to not record any measurable falls at all. In extremely wet summer months such as January 1974 or March 1950, most of

630-539: The floods have receded. Lakes Mipia and Koolivoo are inundated annually, with Mipia often retaining water until the following flood season, but Koolivoo usually dries up by early summer. Lake Machattie is flooded about once in three years. The three lakes are fresh when filled by floods but become increasingly saline as they dry out. The floodplains are characterised by anastomosing channels and waterholes lined with open coolibah woodland, surrounded by grasslands , forblands , samphire and lignum . Average annual rainfall

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660-587: The form of structural bracing. The velocities and hydraulic efficiencies should be meticulously calculated and can be altered by integrating different combinations of geometries, components such a gradients, cascades and an adequate junction angle which is sympathetic to the direction of the watercourse’s flow to minimise turbulent flow, maximise evacuation velocity and to ultimately maximise hydraulic efficiency. Since rivers often serve as political boundaries, confluences sometimes demarcate three abutting political entities, such as nations, states, or provinces, forming

690-462: The late 1960s in rainfall over the Northern Territory and pastoral areas of South and Western Australia that have not been duplicated over Queensland do suggest an enhanced greenhouse effect in the Medieval Warm Period may have caused the Georgina to regularly fill Lake Eyre. However, far too little evidence exists for any certainty of this. Given the economic importance of transport on

720-514: The river can be as wide as 15 to 20 kilometres (9.3 to 12.4 mi) in the upper reaches and in the lower reaches from 25 to 30 kilometres (16 to 19 mi) wide. Inundation can last for months at a time, which can disrupt road and rail transport in the area. The highest recorded flood occurred in January 1974. Flooding occurred at Glenormiston Station in 1885 when somewhere between 12 inches (305 mm) and 17 inches (432 mm) of rain fell over

750-602: The river, including Glenormiston Station, in 2010 following heavy rains locally and further north in the Georgina catchment. Although it is the driest of the three main rivers of the Lake Eyre Basin, there is evidence that the Georgina has, in the past, actually reached the lake more frequently than either the Diamantina or Cooper. Some wave built shingle terraces suggest that during the Medieval Warm Period Lake Eyre held permanent water. Large increases since

780-448: The sites for fortified triangular temples, where they practiced human sacrifice and other sacred rites. In Hinduism , the confluence of two sacred rivers often is a pilgrimage site for ritual bathing. In Pittsburgh, a number of adherents to Mayanism consider their city's confluence to be sacred. Mississippi basin Atlantic watersheds Pacific watersheds Occasionally, "confluence"

810-519: The south draining the northern slopes of the Macdonnell Ranges , the Georgina is formed from several smaller streams over a wide area of north-western Queensland and the eastern Northern Territory. From source to mouth , the Georgina is joined by more than 35 tributaries including the Buckley, Templeton, Burke , Hamilton, Herbert, Ranken, and Sandover rivers; and flows through 26 billabongs . As

840-613: The subsequent transport of metals downstream of the mixing zone." A natural phenomenon at confluences that is obvious even to casual observers is a difference in color between the two streams; see images in this article for several examples. According to Lynch, "the color of each river is determined by many things: type and amount of vegetation in the watershed, geological properties, dissolved chemicals, sediments and biologic content – usually algae ." Lynch also notes that color differences can persist for miles downstream before they finally blend completely. Hydrodynamic behaviour of flow in

870-401: The system to ensure the longevity and efficiency of the structure. Engineers have to design these systems whilst considering a list of factors that ensure the discharge point is structurally stable as the entrance of the lateral culvert into the main structure may compromise the stability of the structure due to the lack of support at the discharge, this often constitutes additional supports in

900-537: Was safe to cross. To alleviate these problems, the Georgina River Bridge was officially opened on 20 December 2002 by Senator Ron Boswell and Steve Breadhauer , Minister for Transport in the Queensland Government . It replaced the previous bridge which was approximately 50 metres (160 ft) south, and is both higher and longer so traffic on the highway can continue to cross during floods. The bridge

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