A weir / w ɪər / or low-head dam is a barrier across the width of a river that alters the flow characteristics of water and usually results in a change in the height of the river level. Weirs are also used to control the flow of water for outlets of lakes, ponds, and reservoirs. There are many weir designs, but commonly water flows freely over the top of the weir crest before cascading down to a lower level. There is no single definition as to what constitutes a weir.
121-705: The Ural , also known as the Yaik / ˈ j aɪ k / , is a river flowing through Russia and Kazakhstan in the continental border between Europe and Asia . It originates in the southern Ural Mountains and discharges into the Caspian Sea . At 2,428 kilometres (1,509 mi), it is the third-longest river in Europe after the Volga and the Danube , and the 18th-longest river in Asia . The Ural
242-574: A communist-led revolution in Afghanistan, Soviet forces invaded the country, ultimately starting the Soviet–Afghan War . In May 1988, the Soviets started to withdraw from Afghanistan , due to international opposition, persistent anti-Soviet guerrilla warfare, and a lack of support by Soviet citizens. From 1985 onwards, the last Soviet leader Mikhail Gorbachev , who sought to enact liberal reforms in
363-626: A troika was designated to take charge. Eventually Joseph Stalin , the General Secretary of the Communist Party , managed to suppress all opposition factions and consolidate power in his hands to become the country's dictator by the 1930s. Leon Trotsky , the main proponent of world revolution , was exiled from the Soviet Union in 1929, and Stalin's idea of Socialism in One Country became
484-595: A Varangian from the Rus' people , named Rurik , was elected ruler of Novgorod in 862. In 882, his successor Oleg ventured south and conquered Kiev , which had been previously paying tribute to the Khazars . Rurik's son Igor and Igor's son Sviatoslav subsequently subdued all local East Slavic tribes to Kievan rule, destroyed the Khazar Khaganate, and launched several military expeditions to Byzantium and Persia . In
605-512: A broad flat plain until it reaches the Caspian a few kilometers below Atyrau , where it forms a fine 'digitate' (tree-like) delta . The river was called Δάϊκος (Daïkos) by Ptolemy in the 2nd century AD. Yulian Kulakovsky reads this as Turkic " Jajyk " or "Яик" and on this basis identifies the Huns as Turkic speakers. However, Gerard Clauson disputes that the name could be of Turkic origin as early as
726-501: A crisis. By 1991, economic and political turmoil began to boil over as the Baltic states chose to secede from the Soviet Union. On 17 March, a referendum was held, in which the vast majority of participating citizens voted in favour of changing the Soviet Union into a renewed federation . In June 1991, Boris Yeltsin became the first directly elected President in Russian history when he
847-442: A dam is designed specifically to impound water behind a wall, whilst a weir is designed to alter the river flow characteristics. A common distinction between dams and weirs is that water flows over the top (crest) of a weir or underneath it for at least some of its length. Accordingly, the crest of an overflow spillway on a large dam may therefore be referred to as a weir. Weirs can vary in size both horizontally and vertically, with
968-979: A deep pit. The climate is continental with frequent and strong winds. Typical annual precipitation is 530 millimetres (21 in). The wetlands at and near the delta of the Ural River are especially important to migrating birds as an important stop-over along the Asian flyway. They host many endemic and endangered species, such as great white pelican , Dalmatian pelican , pygmy cormorant , cattle egret , little egret , greater flamingo , white-headed duck , ferruginous duck , Eurasian spoonbill , glossy ibis , houbara bustard , great black-headed gull , slender-billed gull , squacco heron , common crane , demoiselle crane , slender-billed curlew , black stork , red-breasted goose , lesser white-fronted goose , lesser kestrel , whooper swan , tundra swan , osprey , pallid harrier , short-toed eagle and many others. The pygmy cormorant
1089-406: A derivative of the root of the verb werian, meaning "to defend, dam". The German cognate is Wehr , which means the same as English weir. Commonly, weirs are used to prevent flooding , measure water discharge, and help render rivers more navigable by boat. In some locations, the terms dam and weir are synonymous, but normally there is a clear distinction made between the structures. Usually,
1210-639: A global superpower. After World War II, according to the Potsdam Conference , the Red Army occupied parts of Eastern and Central Europe, including East Germany and the eastern regions of Austria . Dependent communist governments were installed in the Eastern Bloc satellite states. After becoming the world's second nuclear power , the Soviet Union established the Warsaw Pact alliance, and entered into
1331-778: A large confederacy, which was subsequently taken over by the Cumans and the Kipchaks . The ancestors of Russians are among the Slavic tribes that separated from the Proto-Indo-Europeans, who appeared in the northeastern part of Europe c. 1500 years ago. The East Slavs gradually settled western Russia (approximately between modern Moscow and Saint-Petersburg ) in two waves: one moving from Kiev towards present-day Suzdal and Murom and another from Polotsk towards Novgorod and Rostov . Prior to Slavic migration, that territory
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#17330852254891452-401: A large number of Cossacks with pike poles were gathering on the shore; after a signal was given, they rushed on the ice, broke it with their poles, and speared and pulled the fish. Another fishing technique was constructing a weir , known as the uchug ( учуг ) across the river, to catch fish going upstream to spawn. Until 1918, an uchug was set up in the summer and autumn near Uralsk, so that
1573-482: A negative effect on fish species that migrate as part of their breeding cycle (e.g., salmonids ), but it also can be useful as a method of preventing invasive species moving upstream. For example, weirs in the Great Lakes region have helped to prevent invasive sea lamprey from colonising farther upstream. Mill ponds are created by a weir that impounds water that then flows over the structure. The energy created by
1694-415: A range of biota , including poor swimmers. Even though the water around weirs can often appear relatively calm, they can be extremely dangerous places to boat, swim, or wade, as the circulation patterns on the downstream side—typically called a hydraulic jump —can submerge a person indefinitely. This phenomenon is so well known to canoeists, kayakers, and others who spend time on rivers that they even have
1815-416: A rueful name for weirs: "drowning machines". The Ohio DNR recommends that a victim should "tuck the chin down, draw the knees up to the chest with arms wrapped around them. Hopefully, conditions will be such that the current will push the victim along the bed of the river until swept beyond the boil line and released by the hydraulic." The Pennsylvania State Police also recommends to victims, "curl up, dive to
1936-618: A secret protocol within the Molotov–Ribbentrop Pact with Nazi Germany . The Soviet Union later invaded Finland , and occupied and annexed the Baltic states , as well as parts of Romania . On 22 June 1941, Germany invaded the Soviet Union , opening the Eastern Front , the largest theater of World War II. Eventually, some 5 million Red Army troops were captured by the Nazis;
2057-508: A struggle for global dominance, known as the Cold War , with the rivalling United States and NATO . After Stalin's death in 1953 and a short period of collective rule , the new leader Nikita Khrushchev denounced Stalin and launched the policy of de-Stalinization , releasing many political prisoners from the Gulag labour camps. The general easement of repressive policies became known later as
2178-491: A typical mountain river. It then falls into the Yaik Swamp and after exiting it widens up to 5 kilometres (3 mi). Below Verkhneuralsk , its flow is characteristic of a flatland river; there it enters Chelyabinsk and Orenburg Oblasts . From Magnitogorsk to Orsk its banks are steep and rocky and the bottom has many rifts. After Orsk, the river abruptly turns west and flows through a 45-kilometre (28 mi) long canyon in
2299-449: A weir is broad-crested for much of its length, but has a section where the weir stops or is 'open' so that small boats and fish can traverse the structure. A notch weir is any weir where the physical barrier is significantly higher than the water level except for a specific notch (often V-shaped) cut into the panel. At times of normal flow all the water must pass through the notch, simplifying flow volume calculations, and at times of flood
2420-564: Is Moscow . Saint Petersburg is Russia's second-largest city and its cultural capital . The East Slavs emerged as a recognised group in Europe between the 3rd and 8th centuries CE. The first East Slavic state, Kievan Rus' , arose in the 9th century, and in 988, it adopted Orthodox Christianity from the Byzantine Empire . Kievan Rus' ultimately disintegrated; the Grand Duchy of Moscow led
2541-405: Is a flat-crested structure, where the water passes over a crest that covers much or all of the channel width. This is one of the most common types of weir found worldwide. A compound weir is any weir that comprises several different designs into one structure. They are commonly seen in locations where a river has multiple users who may need to bypass the structure. A common design would be one where
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#17330852254892662-473: Is a generic relationship and specific calculations are available for the many different types of weir. Flow measurement weirs must be well maintained if they are to remain accurate. The flow over a V-notch weir (in ft /s) is given by the Kindsvater–Shen equation: where As weirs are a physical barrier, they can impede the longitudinal movement of fish and other animals up and down a river. This can have
2783-509: Is at times included in European political and sports organizations. The river is mostly fed by melting snow (60–70%); the contribution of precipitation is relatively minor. Most of its annual discharge (65%) occurs during the spring floods, which occur in March and April near the mouth and in late April through June upstream; 30% drain during the summer and autumn and 5% in winter. During the floods,
2904-623: Is conventionally considered part of the boundary between the continents of Europe and Asia. The Ural rises near Mount Kruglaya in the Ural Mountains, flows south parallel and west of the north-flowing Tobol , through Magnitogorsk , and around the southern end of the Urals, through Orsk where it turns west for about 300 kilometres (190 mi), to Orenburg , where the river Sakmara joins. From Orenburg it continues west, passing into Kazakhstan, then turning south again at Oral , and meandering through
3025-822: Is deeper and is navigable. Ural River has a spectacular tree-like (or "digitate") shape of the delta (see image). This type of delta forms naturally in the slow rivers which deliver a great deal of sediments and flow into a quiet sea. In the delta, 13.5 kilometres (8.4 mi) from the mouth of the Zolotoy distributary lies Shalyga Island, which is 2.5 kilometres (1.6 mi) long, with heights of 1 to 2 metres (3 to 7 ft) and maximum widths of 0.3 kilometres (980 ft). The tributaries, in order going upstream, are Kushum, Derkul, Chagan , Irtek, Utva , Ilek (major, left), Bolshaya Chobda, Kindel, Sakmara , Tanalyk (major, right), Salmys, Or (major, left) and Suunduk. The Kushum and Bagyrlai are distributaries . The entire length of
3146-547: Is navigated up to Uralsk and there is a port in Atyrau. Fishery is well developed; the commercial fish species include sturgeon , perch , herring , bream , carp and catfish . The delta of Ural River accounts for about half of the fish catchment in Kazakhstan. Also widespread is agriculture, especially growth of melons and watermelons. The city of Atyrau is a major oil producing center of Kazakhstan. Russia Russia , or
3267-543: The Battle of Kursk in the summer of 1943. Another German failure was the Siege of Leningrad , in which the city was fully blockaded on land between 1941 and 1944 by German and Finnish forces, and suffered starvation and more than a million deaths, but never surrendered. Soviet forces steamrolled through Eastern and Central Europe in 1944–1945 and captured Berlin in May 1945. In August 1945,
3388-731: The Brusilov Offensive of the Imperial Russian Army almost completely destroyed the Austro-Hungarian Army . However, the already-existing public distrust of the regime was deepened by the rising costs of war, high casualties , and rumors of corruption and treason. All this formed the climate for the Russian Revolution of 1917, carried out in two major acts. In early 1917, Nicholas II was forced to abdicate ; he and his family were imprisoned and later executed during
3509-470: The Congress of Vienna , which defined the map of post-Napoleonic Europe. The officers who pursued Napoleon into Western Europe brought ideas of liberalism back to Russia, and attempted to curtail the tsar's powers during the abortive Decembrist revolt of 1825. At the end of the conservative reign of Nicholas I (1825–1855), a zenith period of Russia's power and influence in Europe, was disrupted by defeat in
3630-677: The Crimean War . Nicholas's successor Alexander II (1855–1881) enacted significant changes throughout the country, including the emancipation reform of 1861 . These reforms spurred industrialisation, and modernised the Imperial Russian Army, which liberated much of the Balkans from Ottoman rule in the aftermath of the 1877–1878 Russo-Turkish War . During most of the 19th and early 20th century, Russia and Britain colluded over Afghanistan and its neighbouring territories in Central and South Asia;
3751-521: The Eastern Front . With the onset of the Cold War , it competed with the United States for ideological dominance and international influence . The Soviet era of the 20th century saw some of the most significant Russian technological achievements , including the first human-made satellite and the first human expedition into outer space . In 1991, the Russian SFSR emerged from the dissolution of
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3872-600: The Great Northern War (1700–1721), securing Russia's access to the sea and sea trade. In 1703, on the Baltic Sea, Peter founded Saint Petersburg as Russia's new capital. Throughout his rule, sweeping reforms were made , which brought significant Western European cultural influences to Russia. He was succeeded by Catherine I (1725–1727), followed by Peter II (1727–1730), and Anna . The reign of Peter I's daughter Elizabeth in 1741–1762 saw Russia's participation in
3993-672: The Khrushchev Thaw . At the same time, Cold War tensions reached its peak when the two rivals clashed over the deployment of the United States Jupiter missiles in Turkey and Soviet missiles in Cuba . In 1957, the Soviet Union launched the world's first artificial satellite , Sputnik 1 , thus starting the Space Age . Russian cosmonaut Yuri Gagarin became the first human to orbit
4114-681: The Oldowan period in the early Lower Paleolithic . About 2 million years ago, representatives of Homo erectus migrated to the Taman Peninsula in southern Russia. Flint tools, some 1.5 million years old, have been discovered in the North Caucasus . Radiocarbon dated specimens from Denisova Cave in the Altai Mountains estimate the oldest Denisovan specimen lived 195–122,700 years ago. Fossils of Denny , an archaic human hybrid that
4235-556: The Rurik dynasty that ruled Kievan Rus' collectively. Kiev's dominance waned, to the benefit of Vladimir-Suzdal in the north-east, the Novgorod Republic in the north, and Galicia-Volhynia in the south-west. By the 12th century, Kiev lost its pre-eminence and Kievan Rus' had fragmented into different principalities. Prince Andrey Bogolyubsky sacked Kiev in 1169 and made Vladimir his base, leading to political power being shifted to
4356-786: The Russian Civil War . The monarchy was replaced by a shaky coalition of political parties that declared itself the Provisional Government , and proclaimed the Russian Republic . On 19 January [ O.S. 6 January], 1918, the Russian Constituent Assembly declared Russia a democratic federal republic (thus ratifying the Provisional Government's decision). The next day the Constituent Assembly
4477-501: The Russian Federation , is a country spanning Eastern Europe and North Asia . It is the largest country in the world by area , extending across eleven time zones and sharing land borders with fourteen countries . It is the world's ninth-most populous country and Europe's most populous country . Russia is a highly urbanised country including 16 population centres with over a million inhabitants. Its capital and largest city
4598-667: The Russian SFSR —the world's first constitutionally socialist state . Following the Russian Civil War , the Russian SFSR established the Soviet Union with three other Soviet republics , within which it was the largest and principal constituent. At the expense of millions of lives , the Soviet Union underwent rapid industrialisation in the 1930s and later played a decisive role for the Allies in World War II by leading large-scale efforts on
4719-611: The Seven Years' War (1756–1763). During the conflict, Russian troops overran East Prussia , reaching Berlin. However, upon Elizabeth's death, all these conquests were returned to the Kingdom of Prussia by pro-Prussian Peter III of Russia . Catherine II ("the Great"), who ruled in 1762–1796, presided over the Russian Age of Enlightenment . She extended Russian political control over
4840-759: The Siberian River Routes , and by the mid-17th century, there were Russian settlements in eastern Siberia, on the Chukchi Peninsula , along the Amur River , and on the coast of the Pacific Ocean. In 1648, Semyon Dezhnyov became the first European to navigate through the Bering Strait . Under Peter the Great , Russia was proclaimed an empire in 1721, and established itself as one of the European great powers. Ruling from 1682 to 1725, Peter defeated Sweden in
4961-739: The Snowmelt , a levee sheltering the city of Orsk broke. A flood in Orenburg sets over 10.000 houses under water. Also parts of Kazakhstan are concerned. The river begins on the slopes of the Kruglaya Mountain of the Uraltau mountain ridge in South Ural, on the territory of the Uchalinsky District of Bashkortostan . There it has an average width of 60 to 80 metres (200 to 260 ft) and flows as
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5082-412: The Soviet Union , by joining the Russian SFSR into a single state with the Byelorussian , Transcaucasian , and Ukrainian republics. Eventually internal border changes and annexations during World War II created a union of 15 republics ; the largest in size and population being the Russian SFSR, which dominated the union politically, culturally, and economically. Following Lenin's death in 1924,
5203-414: The largest stockpile of nuclear weapons and has the third-highest military expenditure . Russia is generally considered a great power and is a regional power . Internationally, Russia ranks very low in measurements of democracy , human rights and freedom of the press ; the country also has high levels of perceived corruption . As of 2024, Russia has a high-income economy which ranks eleventh in
5324-494: The 10th to 11th centuries, Kievan Rus' became one of the largest and most prosperous states in Europe. The reigns of Vladimir the Great (980–1015) and his son Yaroslav the Wise (1019–1054) constitute the Golden Age of Kiev, which saw the acceptance of Orthodox Christianity from Byzantium , and the creation of the first East Slavic written legal code , the Russkaya Pravda . The age of feudalism and decentralisation had come, marked by constant in-fighting between members of
5445-462: The 11th century and frequently in 12th-century British sources, in turn derived from Russi , 'the Russians' and the suffix -ia . In modern historiography, this state is usually denoted as Kievan Rus' after its capital city. Another Medieval Latin name for Rus' was Ruthenia . In Russian, the current name of the country, Россия ( Rossiya ), comes from the Byzantine Greek name for Rus', Ρωσία ( Rosía ). A new form of
5566-448: The 16th century, Russia expanded east of the Ural Mountains . However, the Tsardom was weakened by the long and unsuccessful Livonian War against the coalition of the Kingdom of Poland and the Grand Duchy of Lithuania (later the united Polish–Lithuanian Commonwealth ), the Kingdom of Sweden , and Denmark–Norway for access to the Baltic coast and sea trade. In 1572, an invading army of Crimean Tatars were thoroughly defeated in
5687-515: The 2nd century, and instead attributes it to Sarmatian origin. Also, the version of origin from the ancient Finno-Ugric and subsequent adaptation by other language groups has not been sufficiently studied (the river originates in the alleged ancestral home of the Finno-Ugric languages ). In modern Finno-Ugric, the closest surviving forms are found: "joki" (Finnish), "jogi" (Karelian), "jā" (Mansi), "ju" (Komi) – river, "jəŋk" (Khanty) – water. Also, hypothetically Finno-Ugric titles may have tributaries of
5808-428: The Byzantine double-headed eagle his own, and eventually Russia's, coat-of-arms. Vasili III united all of Russia by annexing the last few independent Russian states in the early 16th century. In development of the Third Rome ideas, the grand duke Ivan IV ("the Terrible") was officially crowned the first tsar of Russia in 1547. The tsar promulgated a new code of laws ( Sudebnik of 1550 ), established
5929-448: The Caspian Sea which visit its delta and migrate upstream for spawning. In the lower reaches of the river there are 47 species from 13 families. The family Cyprinidae account for 40%, sturgeon and herring make up 11%, perch and herring 9% and salmon 4.4%. The main commercial species are sturgeon , roach , bream , perch , carp , asp and Wels catfish . The rare species include Caspian salmon , sterlet , white salmon and kutum . In
6050-406: The Earth, aboard the Vostok 1 crewed spacecraft on 12 April 1961 . Following the ousting of Khrushchev in 1964, another period of collective rule ensued, until Leonid Brezhnev became the leader. The era of the 1970s and the early 1980s was later designated as the Era of Stagnation . The 1965 Kosygin reform aimed for partial decentralisation of the Soviet economy . In 1979, after
6171-572: The Great changed the name of the state from Tsardom of Russia ( Russian : Русское царство , romanized : Russkoye tsarstvo ) or Tsardom of Muscovy ( Russian : Московское царство , romanized : Moskovskoye tsarstvo ) to Russian Empire ( Rossiiskaia imperiia ). There are several words in Russian which translate to "Russians" in English. The noun and adjective русский , russkiy refers to ethnic Russians . The adjective российский , rossiiskiy denotes Russian citizens regardless of ethnicity. The same applies to
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#17330852254896292-412: The Guberlinsk Mountains. After Uralsk , it flows from north to south, through the territory of West Kazakhstan Region and Atyrau Region of Kazakhstan. There, the river widens and has many lakes and ducts. Near the mouth, it splits into the Yaik and Zolotoy distributaries and forms vast wetlands. The Yaik distributary is shallow, with almost no trees on the shores, and is rich in fish; whereas Zolotoy
6413-406: The Kushum village, which is 76.5 kilometres (47.5 mi) from the mouth. The maximum discharge is 14,000 cubic metres per second (490,000 cu ft/s) and the minimum is 1.62 cubic metres per second (57 cu ft/s). Average turbidity is 280 grams per cubic metre (0.47 lb/cu yd) at Orenburg and 290 grams per cubic metre (0.49 lb/cu yd) near Kushum. The river freezes at
6534-415: The Polish–Lithuanian Commonwealth and annexed most of its territories into Russia , making it the most populous country in Europe. In the south, after the successful Russo-Turkish Wars against the Ottoman Empire , Catherine advanced Russia's boundary to the Black Sea, by dissolving the Crimean Khanate , and annexing Crimea . As a result of victories over Qajar Iran through the Russo-Persian Wars , by
6655-692: The Provisional Government and gave full governing power to the soviets, leading to the creation of the world's first socialist state . The Russian Civil War broke out between the anti-communist White movement and the Bolsheviks with its Red Army . In the aftermath of signing the Treaty of Brest-Litovsk that concluded hostilities with the Central Powers of World War I ; Bolshevist Russia surrendered most of its western territories, which hosted 34% of its population, 54% of its industries, 32% of its agricultural land, and roughly 90% of its coal mines. The Allied powers launched an unsuccessful military intervention in support of anti-communist forces. In
6776-406: The Red Army invaded Manchuria and ousted the Japanese from Northeast Asia, contributing to the Allied victory over Japan. The 1941–1945 period of World War II is known in Russia as the Great Patriotic War . The Soviet Union, along with the United States, the United Kingdom and China were considered the Big Four of Allied powers in World War II, and later became the Four Policemen , which
6897-403: The Russian autocratic state. The destruction of Kievan Rus' saw the eventual rise of the Grand Duchy of Moscow , initially a part of Vladimir-Suzdal . While still under the domain of the Mongol - Tatars and with their connivance, Moscow began to assert its influence in the region in the early 14th century, gradually becoming the leading force in the "gathering of the Russian lands". When
7018-399: The Russian chronicle of 1140 as Yaik. The river was renamed Ural in the Russian language in 1775, by Catherine II of Russia . In the 10th to 16th centuries, the city of Saray-Jük (or Saraichik, meaning "small Sarai") on the Ural River (now in Atyrau Province of Kazakhstan) was an important trade center on the Silk Road . In the 13th century, it became a stronghold of the Golden Horde . It
7139-476: The Russian parliament culminated in a constitutional crisis which ended violently through military force. During the crisis, Yeltsin was backed by Western governments, and over 100 people were killed. In December, a referendum was held and approved, which introduced a new constitution, giving the president enormous powers. The 1990s were plagued by armed conflicts in the North Caucasus , both local ethnic skirmishes and separatist Islamist insurrections. From
7260-554: The Soviet Union as the Russian Federation. A new constitution was adopted, which established a federal semi-presidential system . Since the turn of the century, Russia's political system has been dominated by Vladimir Putin , under whom the country has experienced democratic backsliding and become an authoritarian dictatorship . Russia has been militarily involved in a number of conflicts in former Soviet states and other countries , including its war with Georgia in 2008 and its war with Ukraine since 2014, which has involved
7381-408: The Soviet Union led Russia into a deep and prolonged depression. During and after the disintegration of the Soviet Union, wide-ranging reforms including privatisation and market and trade liberalisation were undertaken, including radical changes along the lines of " shock therapy ". The privatisation largely shifted control of enterprises from state agencies to individuals with inside connections in
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#17330852254897502-523: The Soviet Union. The transitional disorganisation of the country's agriculture, combined with the harsh state policies and a drought, led to the Soviet famine of 1932–1933 ; which killed 5.7 to 8.7 million, 3.3 million of them in the Russian SFSR. The Soviet Union, ultimately, made the costly transformation from a largely agrarian economy to a major industrial powerhouse within a short span of time. The Soviet Union entered World War II on 17 September 1939 with its invasion of Poland , in accordance with
7623-406: The Soviet system, introduced the policies of glasnost (openness) and perestroika (restructuring) in an attempt to end the period of economic stagnation and to democratise the government . This, however, led to the rise of strong nationalist and separatist movements across the country. Prior to 1991, the Soviet economy was the world's second-largest, but during its final years, it went into
7744-493: The Ukrainian leader, Bohdan Khmelnytsky , offered to place Ukraine under the protection of the Russian tsar, Alexis ; whose acceptance of this offer led to another Russo-Polish War . Ultimately, Ukraine was split along the Dnieper , leaving the eastern part, ( Left-bank Ukraine and Kiev ) under Russian rule. In the east, the rapid Russian exploration and colonisation of vast Siberia continued, hunting for valuable furs and ivory. Russian explorers pushed eastward primarily along
7865-438: The Ural River is considered the Europe-Asia boundary by most authoritative sources. Rarely, the smaller, shorter Emba River is claimed as the continental boundary, but that pushes "Europe" much further into "Central Asian" Kazakhstan . The Ural River bridge in Orenburg is even labeled with permanent monuments carved with the word "Europe" on one side, "Asia" on the other. Regardless, Kazakhstan has some European territory and
7986-542: The Ural River. It might be extinct from that region. The reptiles are represented by bog turtles , common water snakes , rat snakes and sand lizard . Bog turtles are found in all waters. Common water snakes live on the banks of canals. Rat snakes and sand lizards are few and inhabit relatively high areas of land. Two more reptiles, Caspian whipsnake and Coluber spinalis , are extremely rare. Among amphibians common are lake frog and green frog. With an estimated 5,000 to 10,000 species, insects exceed all other animals of
8107-440: The Ural, but much of south-eastern Russia, and resulted in a loss of the government control there. After its suppression, Empress Catherine issued a decree of 15 January 1775 to rename most of the places involved in the revolt, in order to erase the memory of it. Thus the Yaik River and the city of Yaitsk were renamed to the Ural River and Uralsk , respectively, and the Yaik Cossacks became the Ural Cossacks. On 6 April 2024, during
8228-516: The Volga-Dnieper region of southern Russia and Ukraine as the urheimat of the Proto-Indo-Europeans . Early Indo-European migrations from the Pontic–Caspian steppe of Ukraine and Russia spread Yamnaya ancestry and Indo-European languages across large parts of Eurasia. Nomadic pastoralism developed in the Pontic–Caspian steppe beginning in the Chalcolithic . Remnants of these steppe civilizations were discovered in places such as Ipatovo , Sintashta , Arkaim , and Pazyryk , which bear
8349-427: The Yaik River, for example Ilek (Erzya "Ilyk" – strength) and Utva (Komi "Ytva" – spring water). In the 10th-Century work De Administrando Imperio , Byzantine Emperor Constantine VII Porphyrogenitus referred to the Ural River as the "Geich." The name Яйыҡ (Yayıq) is currently used in the Bashkir language and Жайық (Zhayıq) in Kazakhstan. In later European texts it is sometimes mentioned as Rhymnus fluvius and in
8470-502: The bottom, and swim or crawl downstream". As the hydraulic jump entrains air, the buoyancy of the water between the dam and boil line will be reduced by upward of 30%, and if a victim is unable to float, escape at the base of the dam may be the only option for survival. There are many different types of weirs and they can vary from a simple stone structure that is barely noticeable, to elaborate and very large structures that require extensive management and maintenance. A broad-crested weir
8591-423: The capital Moscow. In 1612, the Poles were forced to retreat by the Russian volunteer corps, led by merchant Kuzma Minin and prince Dmitry Pozharsky . The Romanov dynasty acceded to the throne in 1613 by the decision of the Zemsky Sobor, and the country started its gradual recovery from the crisis. Russia continued its territorial growth through the 17th century, which was the age of the Cossacks . In 1654,
8712-501: The change in height of the water can then be used to power waterwheels and power sawmills, grinding wheels, and other equipment. Weirs are commonly used to control the flow rates of rivers during periods of high discharge. Sluice gates (or in some cases the height of the weir crest) can be altered to increase or decrease the volume of water flowing downstream. Weirs for this purpose are commonly found upstream of towns and villages and can either be automated or manually operated. By slowing
8833-530: The control of the Golden Horde and consolidated the whole of northern Rus' under Moscow's dominion, and was the first Russian ruler to take the title "Grand Duke of all Rus'". After the fall of Constantinople in 1453, Moscow claimed succession to the legacy of the Eastern Roman Empire . Ivan III married Sophia Palaiologina , the niece of the last Byzantine emperor Constantine XI , and made
8954-446: The crucial Battle of Molodi . The death of Ivan's sons marked the end of the ancient Rurik dynasty in 1598, and in combination with the disastrous famine of 1601–1603 , led to a civil war, the rule of pretenders, and foreign intervention during the Time of Troubles in the early 17th century. The Polish–Lithuanian Commonwealth , taking advantage, occupied parts of Russia, extending into
9075-614: The delta of the river and nearby regions live about 48 animal species belonging to 7 orders ; most common are rodents (21 species) and predators (12). Among them, Bobrinski's serotine and marbled polecat are endemic. Key species are raccoon dog , muskrat (appeared recently), European hare , house mouse , brown rat , and wild boar . Wild boars had a density of 1.2–2.5 per hectare in 2000 and are hunted commercially. Others include elk , fox, wolf, dwarf fat-tailed jerboa , great gerbil , northern mole vole and saiga antelope . The Turkmenian kulan ( Equus hemionus kulan ) used to live at
9196-414: The design of a weir that ensure that fish can bypass the barriers and access upstream habitats. Unlike dams, weirs do not usually prevent downstream fish migration (as water flows over the top and allows fish to bypass the structure in that water), although they can create flow conditions that injure juvenile fish. Recent studies suggest that navigation locks have also potential to provide increased access for
9317-559: The earliest known traces of horses in warfare . The genetic makeup of speakers of the Uralic language family in northern Europe was shaped by migration from Siberia that began at least 3,500 years ago. In the 3rd to 4th centuries CE, the Gothic kingdom of Oium existed in southern Russia, which was later overrun by Huns . Between the 3rd and 6th centuries CE, the Bosporan Kingdom , which
9438-474: The first Europeans to reach and colonise Alaska . In 1803–1806, the first Russian circumnavigation was made. In 1820, a Russian expedition discovered the continent of Antarctica . During the Napoleonic Wars , Russia joined alliances with various European powers, and fought against France. The French invasion of Russia at the height of Napoleon's power in 1812 reached Moscow, but eventually failed as
9559-502: The first Russian feudal representative body (the Zemsky Sobor ), revamped the military, curbed the influence of the clergy, and reorganised local government. During his long reign, Ivan nearly doubled the already large Russian territory by annexing the three Tatar khanates: Kazan and Astrakhan along the Volga , and the Khanate of Sibir in southwestern Siberia. Ultimately, by the end of
9680-571: The first half of the 19th century, Russia also conquered the Caucasus . Catherine's successor, her son Paul , was unstable and focused predominantly on domestic issues . Following his short reign, Catherine's strategy was continued with Alexander I's (1801–1825) wresting of Finland from the weakened Sweden in 1809, and of Bessarabia from the Ottomans in 1812. In North America, the Russians became
9801-655: The fish would not go upstream beyond the Cossacks' land. While the uchug weirs were also known in the Volga Delta , the bagrenye was thought to be a uniquely Ural technique. The Ural Cossacks (known originally as the Yaik Cossacks) resented the attempts by the central government to impose rules and regulations on them, and on occasions rose in rebellions. The largest rebellion, the Pugachev's Rebellion of 1773–75, involved not only
9922-485: The government, which led to the rise of Russian oligarchs . Many of the newly rich moved billions in cash and assets outside of the country in an enormous capital flight . The depression of the economy led to the collapse of social services—the birth rate plummeted while the death rate skyrocketed, and millions plunged into poverty; while extreme corruption, as well as criminal gangs and organised crime rose significantly. In late 1993, tensions between Yeltsin and
10043-533: The internationally unrecognised annexations of Ukrainian territory including Crimea in 2014 and four other regions in 2022 during an ongoing invasion . Russia is a permanent member of the United Nations Security Council ; a member state of the G20 , SCO , BRICS , APEC , OSCE , and WTO ; and the leading member state of post-Soviet organisations such as CIS , CSTO , and EAEU/EEU . It possesses
10164-525: The latter deliberately starved to death or otherwise killed 3.3 million Soviet POWs , and a vast number of civilians, as the " Hunger Plan " sought to fulfil Generalplan Ost . Although the Wehrmacht had considerable early success, their attack was halted in the Battle of Moscow . Subsequently, the Germans were dealt major defeats first at the Battle of Stalingrad in the winter of 1942–1943, and then in
10285-423: The maximum height a species can jump or creates flow conditions that cannot be bypassed (e.g., due to excessive water velocity) effectively limits the maximum point upstream that fish can migrate. In some cases this can mean that huge lengths of breeding habitat are lost, and over time this can have a significant impact on fish populations. In many countries, it is now a legal requirement to build fish ladders into
10406-669: The meantime, both the Bolsheviks and White movement carried out campaigns of deportations and executions against each other, known respectively as the Red Terror and White Terror . By the end of the violent civil war, Russia's economy and infrastructure were heavily damaged, and as many as 10 million perished during the war, mostly civilians. Millions became White émigrés , and the Russian famine of 1921–1922 claimed up to five million victims. On 30 December 1922, Lenin and his aides formed
10527-596: The more recently coined noun россиянин , rossiianyn , "Russian" in the sense of citizen of the Russian state. According to the Primary Chronicle , the word Rus' is derived from the Rus' people , who were a Swedish tribe, and where the three original members of the Rurikid dynasty came from. The Finnish word for Swedes, ruotsi , has the same origin. Later archeological studies mostly confirmed this theory. The first human settlement on Russia dates back to
10648-533: The name Rus ' , Росия ( Rosiya ), was borrowed from the Greek term and first attested in 1387. The name Rossiia appeared in Russian sources in the late 15th century, but until the end of the 17th century the country was more often referred to by its inhabitants as Rus ' , the Russian land ( Russkaia zemlia ), or the Muscovite state ( Moskovskoe gosudarstvo ), among other variations. In 1721, Peter
10769-625: The north-east. Led by Prince Alexander Nevsky , Novgorodians repelled the invading Swedes in the Battle of the Neva in 1240, as well as the Germanic crusaders in the Battle on the Ice in 1242. Kievan Rus' finally fell to the Mongol invasion of 1237–1240, which resulted in the sacking of Kiev and other cities, as well as the death of a major part of the population. The invaders, later known as Tatars , formed
10890-601: The obstinate resistance in combination with the bitterly cold Russian winter led to a disastrous defeat of invaders, in which the pan-European Grande Armée faced utter destruction. Led by Mikhail Kutuzov and Michael Andreas Barclay de Tolly , the Imperial Russian Army ousted Napoleon and drove throughout Europe in the War of the Sixth Coalition , ultimately entering Paris. Alexander I controlled Russia's delegation at
11011-643: The official line. The continued internal struggle in the Bolshevik party culminated in the Great Purge . Under Stalin's leadership, the government launched a command economy , industrialisation of the largely rural country , and collectivisation of its agriculture . During this period of rapid economic and social change, millions of people were sent to penal labour camps , including many political convicts for their suspected or real opposition to Stalin's rule; and millions were deported and exiled to remote areas of
11132-456: The prominent Magnitogorsk ( Magnitogorsk Iron and Steel Works , built in the early 1930s) and Orsk-Khalilovsk metallurgical plants, and the low reaches are used for irrigation. Two reservoirs were created near Magnitogorsk, and there is a hydroelectric plant near the village of Iriklinskaya with the corresponding reservoir. Below Uralsk, there is another reservoir and the Kushumsky channel. The river
11253-413: The rate at which water moves downstream even slightly, a disproportionate effect can be had on the likelihood of flooding. On larger rivers, a weir can also alter the flow characteristics of the waterway to the point that vessels are able to navigate areas previously inaccessible due to extreme currents or eddies . Many larger weirs will have construction features that allow boats and river users to "shoot
11374-412: The region by diversity and biomass. Terrestrial and aquatic insects make up a significant proportion of the diet of birds. Many species are parasitic on birds and transmit infection. Other dominating inhabitants of the river are protozoa , rotifers , Cladocera and copepods . Mollusks are mostly represented by gastropods and bivalves . Water from the upper reaches of the Ural River is used to supply
11495-405: The right and 0.19 km/km in the left side of the basin. The right-side tributaries are typical mountain rivers whereas the left-side tributaries have flatland character. About 200 kilometres (120 mi) from the mouth there is a dangerous spot for shipping called Kruglovskaya prorva ( Russian : Кругловская прорва meaning Kruglovsk abyss). Here the river narrows and creates a strong vortex over
11616-573: The rivalry between the two major European empires came to be known as the Great Game . The late 19th century saw the rise of various socialist movements in Russia. Alexander II was assassinated in 1881 by revolutionary terrorists. The reign of his son Alexander III (1881–1894) was less liberal but more peaceful. Under last Russian emperor, Nicholas II (1894–1917), the Revolution of 1905
11737-427: The river bottom) that reduces the water oxygen content and smothers invertebrate habitat and fish spawning sites. The oxygen content typically returns to normal once water has passed over the weir crest (although it can be hyper-oxygenated), although increased river velocity can scour the river bed causing erosion and habitat loss. Weirs can have a significant effect on fish migration . Any weir that exceeds either
11858-527: The river widens to above 10 kilometres (6 mi) near Uralsk and to several tens of kilometers near the mouth. Water level is highest in later April upstream and in May downstream. Its fluctuation is 3 to 4 metres (10 to 13 ft) in the upper stream, 9 to 10 metres (30 to 33 ft) in the middle of the river and about 3 metres (10 ft) in the delta. The average water discharge is 104 cubic metres per second (3,700 cu ft/s) near Orenburg, and 400 cubic metres per second (14,000 cu ft/s) at
11979-427: The rouble. High budget deficits coupled with increasing capital flight and inability to pay back debts, caused the 1998 Russian financial crisis , which resulted in a further GDP decline. Weir Weir can also refer to the skimmer found in most in-ground swimming pools, which controls the flow of water pulled into the filtering system. The word likely originated from Middle English were , Old English wer ,
12100-845: The seat of the Metropolitan of the Russian Orthodox Church moved to Moscow in 1325, its influence increased. Moscow's last rival, the Novgorod Republic , prospered as the chief fur trade centre and the easternmost port of the Hanseatic League . Led by Prince Dmitry Donskoy of Moscow, the united army of Russian principalities inflicted a milestone defeat on the Mongol-Tatars in the Battle of Kulikovo in 1380. Moscow gradually absorbed its parent duchy and surrounding principalities, including formerly strong rivals such as Tver and Novgorod . Ivan III ("the Great") threw off
12221-422: The smallest being only a few centimetres in height whilst the largest may be many metres tall and hundreds of metres long. Some common weir purposes are outlined below. Weirs allow hydrologists and engineers a simple method of measuring the volumetric flow rate in small to medium-sized streams/rivers or in industrial discharge locations. Since the geometry of the top of the weir is known and all water flows over
12342-402: The source in early November and in the middle and lower reaches in late November. It opens in the lower reaches in late March and in early April in the upper reaches. The ice drift is relatively short. The average depth is 1 to 1.5 metres (3 to 5 ft) near the source, and it increases in the middle reaches and especially near the mouth. The density of underwater vegetation also increases from
12463-408: The source to the mouth, so does the richness of the fauna. The bottom in the upper stream is rocky, with pebble and sand; it changes to silt-sand and occasionally clay downstream. The basin is asymmetrical – its left side from the river is 2.1 times larger in area than the right side; however, the right side is more important for feeding the river. The density of the tributaries is 0.29 km/km in
12584-575: The state of the Golden Horde , which ruled over Russia for the next two centuries. Only the Novgorod Republic escaped foreign occupation after it agreed to pay tribute to the Mongols. Galicia-Volhynia would later be absorbed by Lithuania and Poland , while the Novgorod Republic continued to prosper in the north. In the northeast, the Byzantine-Slavic traditions of Kievan Rus' were adapted to form
12705-523: The time Chechen separatists declared independence in the early 1990s, an intermittent guerrilla war was fought between the rebel groups and Russian forces. Terrorist attacks against civilians were carried out by Chechen separatists, claiming the lives of thousands of Russian civilians. After the dissolution of the Soviet Union, Russia assumed responsibility for settling the latter's external debts. In 1992, most consumer price controls were eliminated, causing extreme inflation and significantly devaluing
12826-401: The true sturgeon, starry sturgeon , and beluga ) in the Ural River and the Caspian. A great variety of fishing techniques existed; the most famous of them was bagrenye ( Russian : багренье , from bagor Russian : багор , meaning pike pole ): spearing hibernating sturgeons in their underwater lairs in mid-winter. The bagrenye was allowed only on one day of the year. On the appointed day,
12947-532: The unification of Russian lands, leading to the proclamation of the Tsardom of Russia in 1547. By the early 18th century, Russia had vastly expanded through conquest, annexation, and the efforts of Russian explorers , developing into the Russian Empire , which remains the third-largest empire in history . However, with the Russian Revolution in 1917, Russia's monarchic rule was abolished and eventually replaced by
13068-515: The water level can rise and submerge the weir without any alterations made to the structure. A polynomial weir is a weir that has a geometry defined by a polynomial equation of any order n . In practice, most weirs are low-order polynomial weirs. The standard rectangular weir is, for example, a polynomial weir of order zero. The triangular (V-notch) and trapezoidal weirs are of order one. High-order polynomial weirs are providing wider range of Head-Discharge relationships, and hence better control of
13189-540: The weir" and navigate by passing up or down stream without having to exit the river. Weirs constructed for this purpose are especially common on the River Thames , and most are situated near each of the river's 45 locks . Because a weir impounds water behind it and alters the flow regime of the river, it can have an effect on the local ecology . Typically, the reduced river velocity upstream can lead to increased siltation (deposition of fine particles of silt and clay on
13310-532: The weir, the depth of water behind the weir can be converted to a rate of flow. However, this can only be achieved in locations where all water flows over the top of the weir crest (as opposed to around the sides or through conduits or sluices) and at locations where the water that flows over the crest is carried away from the structure. If these conditions are not met, it can make flow measurement complicated, inaccurate, or even impossible. The discharge calculation can be summarised as where However, this calculation
13431-528: The world by nominal GDP and fourth at purchasing power parity , relying on its vast mineral and energy resources ; the world's second-largest for oil production and natural gas production . Russia is home to 32 UNESCO World Heritage Sites . According to the Oxford English Dictionary , the English name Russia first appeared in the 14th century, borrowed from Medieval Latin : Russia , used in
13552-449: Was elected President of the Russian SFSR. In August 1991, a coup d'état attempt by members of Gorbachev's government, directed against Gorbachev and aimed at preserving the Soviet Union, instead led to the end of the Communist Party of the Soviet Union. On 25 December 1991, following the dissolution of the Soviet Union , along with contemporary Russia, fourteen other post-Soviet states emerged. The economic and political collapse of
13673-566: Was a Hellenistic polity that succeeded the Greek colonies, was also overwhelmed by nomadic invasions led by warlike tribes such as the Huns and Eurasian Avars . The Khazars , who were of Turkic origin , ruled the steppes between the Caucasus in the south, to the east past the Volga river basin, and west as far as Kyiv on the Dnieper river until the 10th century. After them came the Pechenegs who created
13794-577: Was destroyed in 1395 by the army of Timur but then rebuilt to become the capital of Nogai Horde in the 15th and 16th centuries. It was finally reduced to a village in 1580 by the Ural Cossacks . After the Russian conquest of the Ural basin in the late 16th century, the shores of the Ural became home to the Yaik Cossacks . One of their main activities was fishing for the sturgeon and related fishes (including
13915-639: Was dissolved by the All-Russian Central Executive Committee . An alternative socialist establishment co-existed, the Petrograd Soviet , wielding power through the democratically elected councils of workers and peasants, called soviets . The rule of the new authorities only aggravated the crisis in the country instead of resolving it, and eventually, the October Revolution , led by Bolshevik leader Vladimir Lenin , overthrew
14036-507: Was found at Kostyonki–Borshchyovo , and at Sungir , dating back to 34,600 years ago—both in western Russia . Humans reached Arctic Russia at least 40,000 years ago, in Mamontovaya Kurya . Ancient North Eurasian populations from Siberia genetically similar to Mal'ta–Buret' culture and Afontova Gora were an important genetic contributor to Ancient Native Americans and Eastern Hunter-Gatherers . The Kurgan hypothesis places
14157-568: Was half Neanderthal and half Denisovan, and lived some 90,000 years ago, was also found within the latter cave. Russia was home to some of the last surviving Neanderthals, from about 45,000 years ago, found in Mezmaiskaya cave . The first trace of an early modern human in Russia dates back to 45,000 years, in Western Siberia . The discovery of high concentration cultural remains of anatomically modern humans , from at least 40,000 years ago,
14278-432: Was observed sporadically before 1999 and more regularly after that. Cattle egret is observed since 1990 between April and September (as most other migratory birds in this area), with the total population of several dozen couples. It feeds on frogs, mollusks and small fish. Upstream, there are more of the resident bird species, such as grouse , wild pigeon and partridge . Ural River is also important for many fish species of
14399-567: Was populated by Finno-Ugrian peoples. From the 7th century onwards, the incoming East Slavs slowly assimilated the native Finno-Ugrians. The establishment of the first East Slavic states in the 9th century coincided with the arrival of Varangians , the Vikings who ventured along the waterways extending from the eastern Baltic to the Black and Caspian Seas. According to the Primary Chronicle ,
14520-522: Was the foundation of the United Nations Security Council . During the war, Soviet civilian and military death were about 26–27 million , accounting for about half of all World War II casualties . The Soviet economy and infrastructure suffered massive devastation, which caused the Soviet famine of 1946–1947 . However, at the expense of a large sacrifice, the Soviet Union emerged as
14641-681: Was triggered by the humiliating failure of the Russo-Japanese War . The uprising was put down, but the government was forced to concede major reforms ( Russian Constitution of 1906 ), including granting freedoms of speech and assembly , the legalisation of political parties, and the creation of an elected legislative body, the State Duma . In 1914, Russia entered World War I in response to Austria-Hungary 's declaration of war on Russia's ally Serbia , and fought across multiple fronts while isolated from its Triple Entente allies. In 1916,
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