The Sirwan (, , , ) is a

river A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of ...

and tributary of the

Tigris The Tigris ( ; see #Etymology, below) is the eastern of the two great rivers that define Mesopotamia, the other being the Euphrates. The river flows south from the mountains of the Armenian Highlands through the Syrian Desert, Syrian and Arabia ...

that originates in Iran. The Sirwan (or Sirvan) then runs mainly through eastern

Iraq Iraq, officially the Republic of Iraq, is a country in West Asia. It is bordered by Saudi Arabia to Iraq–Saudi Arabia border, the south, Turkey to Iraq–Turkey border, the north, Iran to Iran–Iraq border, the east, the Persian Gulf and ...

. It covers a total distance of .

Course

It rises near

Hamadan Hamadan ( ; , ) is a mountainous city in western Iran. It is located in the Central District of Hamadan County in Hamadan province, serving as the capital of the province, county, and district. As of the 2016 Iranian census, it had a po ...

, in the

Zagros Mountains The Zagros Mountains are a mountain range in Iran, northern Iraq, and southeastern Turkey. The mountain range has a total length of . The Zagros range begins in northwestern Iran and roughly follows Iran's western border while covering much of s ...

of Iran. Descending through the mountains, for some 32 km it forms the Iran-Iraq border. It finally feeds into the Tigris below

Baghdad Baghdad ( or ; , ) is the capital and List of largest cities of Iraq, largest city of Iraq, located along the Tigris in the central part of the country. With a population exceeding 7 million, it ranks among the List of largest cities in the A ...

. Navigation of the upper reaches of the Diyala is not possible because of its narrow defiles, but the river's valley provides an important trade route between Iran and Iraq.

History

The river is mentioned in

Herodotus Herodotus (; BC) was a Greek historian and geographer from the Greek city of Halicarnassus (now Bodrum, Turkey), under Persian control in the 5th century BC, and a later citizen of Thurii in modern Calabria, Italy. He wrote the '' Histori ...

' '' Histories'' under the name Gyndes, where it is stated that the king

Cyrus the Great Cyrus II of Persia ( ; 530 BC), commonly known as Cyrus the Great, was the founder of the Achaemenid Empire. Achaemenid dynasty (i. The clan and dynasty) Hailing from Persis, he brought the Achaemenid dynasty to power by defeating the Media ...

dispersed it by digging 360 channels as punishment after a sacred white horse perished there. The river returned to its former proportions after the channels disappeared under the sand. The Battle of Diyala River took place in 693 BC between the forces of the Assyrian empire and the Elamites of southern Iran.

Name

Its origin in Kurdish and Persian is called "Sirwan", meaning 'roaring sea' or 'shouting river', as well as being the name of an ancient city near Ilam city in Iran. In the

Sassanid The Sasanian Empire (), officially Eranshahr ( , "Empire of the Iranian peoples, Iranians"), was an List of monarchs of Iran, Iranian empire that was founded and ruled by the House of Sasan from 224 to 651. Enduring for over four centuries, th ...

and early Islamic periods, the lower course of the river formed part of the

Nahrawan Canal The Nahrawan Canal () was a major irrigation system of the Sasanian and early Islamic periods in central Iraq, along the eastern banks of the Tigris and the lower course of the Diyala River. Created in the 6th century, it reached its peak under th ...

. The

Diyala Governorate Diyala Governorate ( ) or Diyala Province is a Governorates of Iraq, governorate in northeastern Iraq. Provincial Government *Governor: Muthanna al-Tamimi *Deputy Governor: Mohammed Jassim al-Jubouri Council Geography Diyala Governorate ...

in Iraq is named after the river.

Dams

In Iran the Daryan Dam is currently under construction near Daryan in

Kermanshah Province Kermanshah province () is one of the 31 provinces of Iran, bordering Iraq. Its capital is the city of Kermanshah. According to a 2014 segmentation by the Ministry of Interior (Iran), Ministry of Interior, it is the center of Regions of Iran ...

. The purpose of the dam is to divert a significant portion of the river to Southwestern Iran for irrigation through the long Nosoud Water Conveyance Tunnel and to produce

hydroelectric Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...

power. In Iraq, the river first reaches the Darbandikhan Dam which generates hydroelectric power and stores water for irrigation. It then flows down to the Hemrin Dam for similar purposes. In the lower Diyala Valley near Baghdad the river is controlled by the Diyala Weir which controls floods and irrigates the area northeast of Baghdad. File:Lake Darbandikhan.jpg, Lake Darbandikhan File:Darbandikhan Dam Spillway USACE NWD.jpg, Darbandikhan Dam File:Diyala Weir3 USACE NWD.jpg, Diyala Weir

References

{{coord, 33.2208, N, 44.5064, E, source:kolossus-dewiki, display=title Rivers of Iraq Rivers of Iran Tributaries of the Tigris River International rivers of Asia Geography of Iraqi Kurdistan Iranian Kurdistan Iran–Iraq border Diyala Governorate Landforms of Kurdistan province Landforms of Kermanshah province