In the Chuy Valley below Tokmok
|Native name||Чу, Чүй, Шу|
|Source||confluence of Joon Aryk and Kochkor River|
|- location||Kochkor District, Naryn Region, Kyrgyzstan|
|- elevation||1,802 m (5,912 ft)|
|Mouth||Akjaykyn system of lakes|
|South Kazakhstan Region, Kazakhstan|
|135 m (443 ft)|
|Length||1,067 km (663 mi)|
|Basin size||67,500 km2 (26,100 sq mi)|
|- left||Ala-Archa River, Kara-Balta River, Ysyk-Ata River, Alamudun River, Ak-Suu River|
|- right||Chong-Kemin River, Kichi-Kemin River|
The Chu (Shu or Chui, Chuy) (Kazakh: Шу/Şuw, شۋ; Kyrgyz: Чүй, Çüy, چۉي; Dungan: Чў, Çw (from 楚 chǔ); Russian: Чу) is a river in northern Kyrgyzstan and southern Kazakhstan. Of its total length of approximately 1 067 kilometres (663 miles), the first 115 kilometres are in Kyrgyzystan, then for 221 kilometres the river is the border between Kyrgyzystan and Kazakhstan, and the last 731 kilometres are in Kazakhstan. It is one of the longest rivers in Kyrgyzstan and in Kazakhstan.
The Chuy Region, the northernmost and most populous administrative region of Kyrgyzstan, is named after the river; so are Chuy Avenue, the main street of Bishkek, and the city of Shu in Kazakhstan's Jambyl Region.
The Chu River 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 (Russian: Боомское ущелье, Boomskoye ushchelye), the river enters the comparatively flat Chuy Valley, within which lie the Kyrgyz capital of 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 Chuy Valley for farming, on both the Kyrgyz and Kazakh sides of the river.
As the Chu flows through the Chuy 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, like many other rivers and streams that drain northern Kyrgyzstan it eventually disappears in the steppe, short of reaching the Syr Darya, although it has sometimes reached that river in wet years.
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).
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.
Ecology and environment
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.
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.
In Kyrgyzstan, 4892 rivers and canals flow into Chu River. The list of the major tributaries include:
- Chong-Kemin River
- Kichi-Kemin River
- Kara-Konuz River
- Shamshy River
- Ysyk-Ata River
- Alamudun River
- Ala-Archa River
- Jylamysh River
- Ak-Suu River
- Kara-Balta River
In the Boom Gorge
In the Chuy Valley near Milyanfan
Near Korday border crossing
Near Shu, Kazakhstan
- Great Soviet Encyclopedia
- Barthold, W. "Balāsāg̲h̲ūn or Balāsaḳūn." Encyclopaedia of Islam. Brill Online. Universiteitsbibliotheek Leiden: Brill Academic Publishers.
- "Profile of town Tokmok (in Russian)". Retrieved 2010-03-10.
- "Kyrgyz State Agency for Hydrometeorology: water quality". Archived from the original on 2011-07-22. Retrieved 2010-03-10.
- Department of Ecological Monitoring (2010). Information Bulletin on Status of the Environment in the Republic of Kazakhstan in 2009 (Report). Ministry of Environment Protection of the Republic of Kazakhstan.
- Чүй облусу:Энциклопедия [Encyclopedia of Chuy Oblast] (in Kyrgyz and Russian). Bishkek: Chief Editorial Board of Kyrgyz Encyclopedia. 1994. p. 718. ISBN 5-89750-083-5.
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