Sir Darya River

The Sir Darya River (also transliterated as Syrdarya, Sir Darya or Sirdaryo, in Kazakh: Сырдария; Tajik Сирдарё; Uzbek Sirdaryo; Arabic سيحون - Siːħuːn) is a long river in Asia Central flowing in W and NW directions through Uzbekistan, Tajikistan and Kazakhstan until it empties into the North Aral Sea. It is the Orexartes or Yaxartes of the classical Greco-Roman sources.

It rises in the extreme east of Uzbekistan, at the confluence of the Naryn and Kara Daria rivers. It has a length of 2,212 km, but, with the Naryn River, it reaches 3,078 km which places it among the 30 longest rivers on Earth. It drains a vast basin of 782,669 km², although currently barely 200,000 km² actually contributes its waters to the main stream.

History and etymology

Sir Daria at your pass through Juyant in Tajikistan.

The ancient Greeks knew him by the names Jaxartes ὁ Ιαξάρτης (this name was later transmitted to the Romans through the Greek authors) and Orexartes. He delimited the northern limit of the conquests of Alexander the Great, who would have reached its shores and would have founded in 329 a. C. the city of Alexandria Escate (literally, "the most distant from Alexandria") as a permanent garrison. In reality, he would only have renamed (and possibly enlarged) the city of Cyropolis founded by King Cyrus the Great of Persia, more than two centuries earlier. The city is now known as the name of Khujand.

The current name comes from the Persian language (سیردریا, Yakhsha Arta, meaning the "Great Pearly", a reference to the color of river water) and has long been used in the East, but it is more recent in Western literature: before the 20th century, the river was known by various versions of its ancient Greek name.

In medieval Islamic writings, the river was known as Sayhoun (سيحون), one of the four rivers of Paradise (the Amu Darya was also known as Jayhoun, the name of another of the four).

Geography

Dawn in Winter at Sir Darya (Baikonur)

This river, corresponding to the endorheic basin of the Aral Sea, has two sources in the Tian Shan mountain (in Mandarin, the «heavenly mountain»): the Naryn river (807 km), in Kyrgyzstan, and the Kara Daria river (177 km) in eastern Uzbekistan. The river runs about 2,212 kilometers through Kazakhstan, in a west and north-south direction, until it empties into the Aral Sea. Its annual flow is very modest, only about 37 km³ per year, half that of its sister river, the Amu Darya.

On the way it irrigates the most fertile cotton crops in all of Central Asia and passes through the cities of Kokand, Khujand, Kyzylorda and Turkestan.

An extensive system of canals, some built in the 18th century by the khans of Kokand, run through the regions where the river flows. The massive expansion of irrigation during the Soviet period to irrigate cotton reduced the flow of the river and was the cause of an ecological disaster in the region: the drying up of the Aral Sea. With millions of people now settled in these cotton areas, it is unclear how the situation could be rectified.

Along its course, it fills the Kayrakum Reservoir in Tajikistan, the Chardara Reservoir in Kazakhstan, and the smaller Farkhad Reservoir in Uzbekistan. On the Naryn River, its largest tributary, is the large Toktogul reservoir and the smaller Kambarata. On its other tributary, the Kara Daria River, is the Andijan Reservoir in Uzbekistan.

Ecological damage

The massive expansion of irrigation canals in Middle and Lower Sir Darya during the Soviet period to irrigate cotton and rice fields caused ecological damage in the area. The amount of water withdrawn from the river was such that at some periods of the year no water reached the Aral Sea at all. The Amu Darya in Uzbekistan and Turkmenistan faced a similar situation.

Uranium concentration of stream water increases in Tajikistan with values of 43 μg/L and 12 μg/L; the WHO guideline value for drinking water of 30 μg/L is partially exceeded. The main input of uranium occurs upstream, in Uzbekistan and Kyrgyzstan.

The fluvial investment of the North

Traced from one of the main routes proposed for the transfer of water (through a Yenisei-Ob channel, going down the Ob, going up the Irtysh and the Ishim, and then by a channel to the Aral Sea basin). The plan would include other channels (not shown) to take the water further south.

The Northern River Inversion or Siberian River Inversion was an ambitious project to divert the flow of the northern rivers of the Soviet Union, which drained "uselessly" in the Arctic Ocean, to the south, towards the populated agricultural areas of Central Asia, which lack water..

Research and planning work on the project began in the 1930s and was carried out on a large scale from the 1960s to the early 1980s. The controversial project was abandoned in 1986, mainly for environmental reasons, without that many real works were carried out.