Chu (river)

The Chu is formed by the confluence of the rivers Joon Aryk and Kochkor, in the Kochkor District of the Naryn Region. After approaching within a few kilometres of Lake Issyk-Kul (near Balykchy), without either flowing into the lake or draining it, it turns towards the northwest. In the 1950s an old riverbed called Ketmaldy (also Buugan) linked the Chu River and Issyk Kul. During floods part of Chu water would reach the lake, but such outflow has not been seen since the construction of the Orto-Tokoy Reservoir. After passing through the narrow Boom Gorge ({{langx|ru|Боомское ущелье}}, Boomskoye ushchelye), the river enters the comparatively flat Chüy Valley, within which lie the Kyrgyz capital Bishkek and the Kazakh city of Shu. Much of the Chu's water is diverted into a network of canals, such as the Great Chüy Canal, to irrigate the fertile black soils of the Chüy Valley for farming, on both the Kyrgyz and Kazakh sides of the river.

As the Chu flows through the Chüy Valley, it forms the border between Kyrgyzstan and Kazakhstan for more than a hundred kilometres, but then it leaves Kyrgyzstan and flows into Kazakhstan, where it flows at the northern edge of the Moiynkum Desert, with lake Kokuydynkol close to its channel. In wet years it may reach the endorheic salt lake Akzhaykyn, located among the vast solonchaks of the Ashchykol Depression.{{cite web|url=https://maps.vlasenko.net/smtm1000/l-42.jpg|title=L-42 Topographic Chart (in Russian)|access-date=8 November 2022}}

File:Syrdaryamap.png

The area of this river was originally home to the Iranian Sughds who spoke Soghdian, an Eastern Iranian language.{{cite book

|last = Barthold

|first = W.

|title = "Balāsāg̲h̲ūn or Balāsaḳūn." Encyclopaedia of Islam.

|publisher = Brill Academic Publishers

|location = Brill Online. Universiteitsbibliotheek Leiden

|url = http://www.brillonline.nl/subscriber/entry?entry=islam_SIM-1131

}}{{Dead link|date=June 2022 |bot=InternetArchiveBot |fix-attempted=yes }}

During the Middle Ages, the area was strategically important. It was the setting of Suyab, the capital of the Western Turkic Khaganate and Balasagun, the capital of the Qara Khitai (Western Liao dynasty).

The Chu River posed a risk of flooding for settlements located in the Chu Valley. In the winter of 1878, an ice gorge formed on the Chu River upstream from Tokmok, the administrative centre of Semirechye Province. This was followed by severe flooding that damaged the town and the province's capital was moved to Pishpek (Bishkek).{{cite web| url = http://www.citykr.kg/tokmok.php#ser1| title = Profile of town Tokmok (in Russian)| access-date = 2010-03-10| archive-url = https://web.archive.org/web/20100419153716/http://www.citykr.kg/tokmok.php#ser1| archive-date = 2010-04-19| url-status = dead}}

The river flow is regulated by the dam at Orto-Tokoy Reservoir in Kyrgyzstan built in 1957 and the dam at Tasotkel Reservoir in Kazakhstan built in 1974.

The Kyrgyz State Agency for Hydrometeorology and the Kazakhstan Hydrometeorological Service (Kazhydromet) operate a number of water quality monitoring stations on the Chu River and its tributaries.{{cite web

|url = http://www.meteo.ktnet.kg/unzps/unzps_voda_arch.php

|title = Kyrgyz State Agency for Hydrometeorology: water quality

|access-date = 2010-03-10

|url-status = dead

|archive-url = https://web.archive.org/web/20110722132012/http://www.meteo.ktnet.kg/unzps/unzps_voda_arch.php

|archive-date = 2011-07-22

}}

According to the Kyrgyz State Agency for Hydrometeorology, in 2004–08 the water pollution index of the Chu River in the Chu Valley ranged from 0.25 to 0.7 units, which is interpreted as Class II ("Clean water"). The only exception was a monitoring point downstream of Vasilyevka village where the water pollution index ranged from 0.4 to 1.2 units and water quality was assessed as Class II(Clean)/Class III ("Moderately polluted").

According to the Kazakhstan Hydrometeorological Service (Kazhydromet), the water pollution index of the Shu (Chu) River in the Jambyl Region of Kazakhstan amounted to 2.01 (Class III, "Moderately polluted") in 2008, and 1.83 (Class III, "Moderately polluted") in 2009. Such water quality parameters as biochemical oxygen demand, nitrites, copper, and phenols exceeded the maximum allowable concentrations.{{Cite report |title=Information Bulletin on Status of the Environment in the Republic of Kazakhstan in 2009 |url=http://www.eco.gov.kz/ekolog/buleten/bul_2009.rar |author=Department of Ecological Monitoring |year=2010 |publisher=Ministry of Environment Protection of the Republic of Kazakhstan }}{{Dead link|date=July 2019 |bot=InternetArchiveBot |fix-attempted=yes }}

In Kyrgyzstan, 4892 rivers and canals flow into Chu River.{{cite book

|title = Чүй облусу:Энциклопедия

|trans-title = Encyclopedia of Chüy Oblast

|publisher = Chief Editorial Board of Kyrgyz Encyclopedia

|language = ky, ru

|location = Bishkek

|year = 1994

|isbn = 5-89750-083-5

|pages = 718

}} The main tributaries are, from source to mouth:

• Kochkor (left)
• Joon Aryk (right)
• Chong-Kemin (right)
• Kichi-Kemin (right)
• Kara-Konguz (right)
• Shamshy (left)
• Ysyk-Ata (left)
• Alamüdün (left)
• Ala-Archa (left)
• Jylamysh (left)
• Kakpatas (right)
• Ak-Suu (left)
• Kuragaty (left)

Image:E8145-Chu-River.jpg|In the Boom Gorge

Image:balbal.jpg|A medieval balbal near Burana Tower in the Chüy Valley

Image:E8046-Chuy-Valley-Milyanfan-east.jpg|In the Chüy Valley near Milyanfan

Image:E7858-Korday-Chu.jpg|Near Korday border crossing

Image:E7840-Shu-city-river-crossing.jpg|Near Shu, Kazakhstan

• Chu-Ili Range

{{Notelist}}

{{commons category|Chu River}}

{{Rivers of Kazakhstan}}

{{Rivers of Kyrgyzstan}}

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