Usboi

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Central Asia with the Amu Darya together with the presumed ancient river bed of the Amu Darya and the Western Usboi; without Kelifer Usboi (from John Bartholomew's XXth Century Citizen's Atlas, 1903)

The Usboi ( Uzbekistan O'zbo'y , Russian Узбой ) is a flow in today's Turkmenistan , with a plurality of arms, the tributaries of the Amudarja formed and dried up in the 16th century by shifting the Amudarja. The northwestern (not continuous) arm of the river is usually shown on current maps, as it now carries water again seasonally as part of a drainage system, but most of it seeps into the desert in the Balkans. The connecting arms as historically continuous flowing water from the Amu Darya to the Caspian Sea are controversial.

Known rivers

Map of Western Usboi from 1913
Schematic representation of the current river bed of the western Usboi. The Usboi does not carry water over the entire length of the river bed.

Secured is a section of the Usboi, which led at the western end of the Kjurendag (near Serdar ) along the Great and Small Balkans to Nebit-Dag ( Balkanabat ), today's end point of the Karakum Canal . The southernmost tributary, the Kelifer Usboi, is still secured. It led the Amu Darya from Kelif to before Kerki and flowed through the Obruchev steppe to the west into the depression near Mary . The further course between these sections could not be fully reconstructed. It should roughly correspond to today's Karakum Canal, during the construction of which numerous sections of the Usboi were exposed. The Western Usboi begins at Igdi and runs in a westerly direction, where it met the original bed between the Greater and Lesser Balkans and led to Nebit-Dag. From Nebit-Dag it should have flowed south of the Balkan Bay into the Caspian Sea.

Another course of the river, which became the most important in the Holocene , is in northwestern Turkmenistan. The historically secured northern arm of the Usboi begins in the Sarykamysh Depression , where it was fed by a spring south of Lake Samykamis. It is also suspected that he might have extended the Amu Darya, which was diverted to the west, across the Kunjadarya and Daudan rivers. In this section it flows west of the Zaunguz Desert, circles the Kaplankyr Plateau east and south, until it reaches the Western Usboi east of Igdi, the southern bend of the Usboi lies directly at Igdi. The plausible continuous connection could have led the Amu Darya over the Sarykamyschsee to the Caspian Sea . The connection between Amudarja and Usboi, i.e. the tributary of the Sarykamysh lakes, was the Daryalik, the northernmost point of which is below Köneürgenç (on the map called Kone Urgenj or in German Kunja-Urgensch ). According to this, a continuous river would have resulted from the Amu Darya via Daryalik, the Sarykamysch Depression, the Usboi and Western Usboi to the Caspian Sea. Together with the northern part of the Amu Darya, which begins in the Sarykamysh Delta, this river would have been 550 km long, with all bends 775 km. The gradient to the Caspian Sea is 75 meters, 40 meters of which alone over the last 200 km. It runs through steep slopes and former waterfalls. The deepest rocks extend along the river bank. The river was 20–30 m wide and its valleys were in some places 4–6 km wide.

Since 2000, Turkmenistan has tried to drain the excess water brought in by irrigation through drainage systems in order to ward off soil salinization caused by rising groundwater. One component of this system is the sink Karaschor with the seasonal water-bearing Karakumsee or Russian Озеро Каракум where the lake of the Golden Age will be built. It is supposed to drain over the former river bed of the middle course of the Usboi, which still carries water in rainy seasons, e.g. B. Can be seen on Google Maps. The Daschogus collector, one of two tributaries of the new artificial lake, follows about half of the bed of the Usboi.

It is also assumed that an arm of the (paleo) Oxus runs through the Ungus valley roughly in the middle of the Karakum, where rivers have also been found. In the same river bed there is also an irrigation canal today, today's (non-navigable) Turkmen main irrigation canal, which is clearly visible on satellite images north of Turkmenabat in a westerly direction due to the extensive flood plains. It is not identical to the route of the main Turkmen Canal planned in the 1930s. The Oxus should have met the Western Usboi there before Igdi (see map).

history

Tectonic movements in the Pliocene raised and lowered the region around the Aral Sea. These changed the course of the rivers, mainly the Amu Darya and its tributaries, to which the Usboi belonged. The Ustyurt plateau protruded into the Aralo-Caspian lowlands as a peninsula. It first separated the Caspian Sea from the Aral Sea at Bala-İşem, then the Usboi valley and other natural connecting channels between the two lakes formed. The development of the coastlines can be modeled by examining various transitional deposits of Caspian molluscs (molluscs), salt deposits from dried-up water bodies (Sors) on the former coastlines, salt flats (Takyrs) and other prehistoric evidence. Evidence of the changes in both lakes due to changes in the amount of water and the development of irrigation have been given by researchers and historians since ancient times.

Usboi and Western Usboi

During this time, the Amu Darya flowed through the Sarykamysh Depression and from there through the Usboi, the bed of which can be detected from the southern edge of the Sarykamysch Depression in the Kaplankyr Nature Reserve , east and south around the Karaschor depression along the Great and Lesser Balkans south of the Balkan bus in the Caspian Sea. Already in ancient times it was described by Herodotus as a branch of Amu Darya and the medieval authors (Muqaddasiy, Hamdallah, Qazviniy, Hofizi Abru, Abulgʻoziy) also adopted this view.

This connection remained until the Pleistocene . Neolithic settlements and ceramics from the Bronze Age, as well as places from the 7th to 5th centuries BC, were found on the shores of Lake Sarykamysh. Discovered. Around 3000 BC BC and around 1000 BC The connection was likely to have been interrupted because the water level in the Aral Sea was particularly high at that time. After that, the Amu Darya shifted again to the east and no longer flowed into the Saryiamish Delta, but into the Aral Sea. At times (the exact period is unknown) part of the Oxus Delta (Amudarja Delta) near the Aral Sea was also flooded and bound the Aral Sea there. The bed of the Western Usboi should not have dried out. This course was investigated by Vladimir Obruchev in 1886 . He found a well south of the Samykamischsees on a road to Khiva : "200 steps to the west of Bala-ISEM fountain on the Sardar Khiva Street. Between the sandy hills, sandstone is not that important. This masterpiece, Uzboydur, has caused great controversy among scholars of the world. It has not yet been fully investigated. ”At the time, it was controversial whether the Usboi actually linked the Amu Darya with the Caspian Sea or whether the Usboj valley was“ only a product of the separation of the Aral Sea from the Caspian Sea ”.

A river culture settled on the banks of the Usboi from the 5th century BC to the 17th century AD. It is believed that the northern and western Usboi existed until the 9th century, after which a dam was built at Gurgandsch ( Köneürgenç ) for irrigation purposes and to protect the capital of the Khorezm Shahs. He must have led the Amu Darya into the Aral Sea. In addition to reports about the dam, this assumption is also supported by the fact that from the 10th century to 1310 there are no more reports about a river estuary into the Caspian Sea, but after that until 1575. In addition, a historical high at the Aral Sea was documented for 1220. The region had one of the most sophisticated irrigation systems on earth until 1221. That year, Genghis Khan had the city captured in a fierce battle and destroyed the dam. The city was flooded and the Amu Darya poured again over the Usboi into the Caspian Sea and the canal system gradually fell into disrepair. Since the Amu Darya recently shifted eastwards, it could no longer reach the Sarykamysh Depression and flowed into the Aral Basin. The Usboi fell dry and the tribes on the river gave up their settlements. The survivors led a nomadic way of life.

Tradition has it that since 1575 the Amu Darya flowed back into the Aral Sea. It was believed that the eastern Oxus broke through some hills. But dams were built again to keep the Turkmens out of water. In 1879, through the merging of older news, local tradition and the analysis of orographic conditions, evidence was obtained that the river was diverted from the Caspian Sea by human influence and not by uplifting the Aralocaspic Plain. It was thought possible to reactivate this bed as a canal not only for irrigation purposes, but also to create “a drivable waterway for Russia to the heart of its inner-Asian provinces.” In the 1950s it became part of Stalin's “Great Plan for Transformation of Nature “ planned the main Turkmen Canal , which was abandoned after Stalin's death. It was to be built from Tachia-Tasch (today Taxiatosh ) in the Sarykamysch Delta over the former bed of the Usboi to Krasnovodsk (today Turkmenbaşy). It would have been 1100 km long (see Karakum Canal # differentiation from the Turkmen Main Canal ).

Kelifer Usboi

Kelifer Usboi (Bras de Tokai) on a French map (1734)

The Kelifer Usboi marks a further course in the south to the Caspian Sea. The adjacent map from 1734 (with errors) is roughly based on the known altitude and assumes a continuous river. Individual sections could only be reconstructed with the construction of the Karakum Canal. Whether it ever flowed continuously to the Caspian Sea is still unproven. When the Amu Darya advanced further north, it is likely to have formed various oxbow lakes and, similar to Hari Rud (Tedschen) and Murgab, have dried up in this desert region today . This eastern branch was historically secured. His bed was reactivated in the 1950s from Kerki for the construction of the Karakum Canal. In the southern Karakum, various sections of the Usboi were found during canal construction. The exact historical course, however, remained unknown.

Current environmental pollution in the Usboi catchment area

At least the main branch of the Usboi, which was particularly important for the people in the Holocene, has again become important as a drainage channel due to the current environmental problems. As a result of ruthless irrigation projects along the Amu Darya, water broke through to Lake Sarykamysh in 1971, which was not stopped. At least from the 4th millennium BC to the first half of the first millennium BC. BC water seeped underground into the Caspian Sea along the Sarykamyschsee.

Due to the modern irrigation systems, the groundwater level rises again, whereby salt is washed to the surface. Around 80 percent of the agricultural land is now saline. With the start of construction of a new drainage system and two collecting canals up to the Karaschor basin in 2000, attempts were made to divert the salty groundwater before it can salty the surrounding area. In addition to the extensive dryness of the Aral Sea, there are further dangers in the fact that over-fertilization and pesticide pollution not only damage the Golden Sea, but also pollute the Caspian Sea. In addition, the peasantry asked for the salt to be flushed out of the Amu Darya with more and more water. This would then be missing in Uzbekistan and is therefore geopolitically explosive. The problem of soil salinization also affects the irrigation area around the non-concreted Karakum Canal.

Trivia

Uzboi Vallis, photographed on September 24, 2014

The Uzboi Vallis river bed on Mars was named after the Usboi. It was photographed by the 2001 Mars Odyssey orbiter on May 31, 2014 .

literature

Individual evidence

  1. ↑ cf. The new large Bertelsmann World Atlas. Wissen Media Verlag GmbH (licensed edition), Gütersloh and Munich, 2003
  2. ↑ УЗБОЙ in the Geographical Dictionary Ecosystem (Russian)
  3. ↑ a b c Amu or Amu-darja - Article in Brockhaus Konversationslexikon, FA Brockhaus in Leipzig, Berlin and Vienna, 14th edition, 1894–1896
  4. ↑ a b c The Aral Sea and South Prearalie. cawater-info.net, April 22, 2019, accessed April 22, 2019
  5. ↑ Map of the Usboi, origin: USSR - researchgate.net, accessed April 22, 2019
  6. ↑ The term "Daryalik" in the great Soviet encyclopedia.
  7. ↑ a b c d P. Tolstov S .: Po drevnim del'tam Oksa i YAksarta. M., 1962; Kes AS, Ruslo Uzboy i yego genezis ("Tr. Inta geografii AN SSSR", ML, 1939, t.30). New edition Let Me Print 2013, ISBN 978-5-458-40504-1 (Russian)
  8. ↑ a b c d A lake in the middle of the desert. The press, June 11, 2008
  9. ↑ General map of Turkmenistan: At different times in the past the Amu Darya River flowed.
  10. ↑ a b Archaeological finds provide information about earlier water levels: The mirror of the Aral Sea over time . In: Neue Zürcher Zeitung . November 22, 2006, ISSN  0376-6829 ( nzz.ch [accessed March 7, 2017]).
  11. ↑ Coordinates of Bala İşem Fountain 40 ° 15 N, 57 ° S
  12. ↑ Vladimir Obruchev: Избранные работы по географии Азии (Selected Works on the Geography of Asia). М .: Государственное издательство географической литературы, 1951. V. 1. - p. 169.
  13. ↑ a b Alexandr Ivanovitch Gloukhovsky: The Passage of the Water of the Amu Darya by its old bed into the Caspian Sea. St Petersburgh, 1893. (New edition: University Press of the Pacific, 2004. ISBN 978-1-4102-1540-6 )
  14. ^ Ryszard Kapuściński, Martin Pollack (translator): Empire: Soviet forays. AB - The Other Library. Berlin, 2015. ISBN 978-3-8477-2008-9 , ISBN 3-8477-2008-2
  15. ↑ Amu Darja - Article in Meyers Konversationslexikon. Publishing house of the Bibliographisches Institut, Leipzig and Vienna, fourth edition, 1885–1892
  16. ↑ Uzboi Vallis - ESA website, June 27, 2018 (English)