The Sirwan (, , , ) is a river and tributary of the Tigris that originates in Iran. The Sirwan (or Sirvan) then runs mainly through eastern Iraq. It covers a total distance of .
Course
It rises near
Hamadan, in the
Zagros Mountains of Iran. Descending through the mountains, for some 32 km it forms the Iran-Iraq border. It finally feeds into the Tigris below
Baghdad. 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'
Histories under the name Gyndes, where it is stated that the king Cyrus the Great 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. Upon its confluence with the
Tanjaro river in
Darbandikhan Dam in the Sulaymaniyah Governorate of Northern Iraq, its name changes to
Diyala River. In the
Sassanid and early Islamic periods, the lower course of the river formed part of the
Nahrawan Canal. The Diyala Governorate in Iraq is named after the river.
Dams
In Iran the
Daryan Dam is currently under construction near Daryan in Kermanshah Province. 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 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.
