The Alwand or Halwan River ( ar, نهر حلوان, ku, Çemê Elwen ,چەم ئەڵوەن, fa, رود الوند) is a river in eastern

Iraq Iraq,; ku, عێراق, translit=Êraq officially the Republic of Iraq, '; ku, کۆماری عێراق, translit=Komarî Êraq is a country in Western Asia. It is bordered by Turkey to Iraq–Turkey border, the north, Iran to Iran–Iraq ...

and western

Iran Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...

. It rises in the

Zagros Mountains The Zagros Mountains ( ar, جبال زاغروس, translit=Jibal Zaghrus; fa, کوه‌های زاگرس, Kuh hā-ye Zāgros; ku, چیاکانی زاگرۆس, translit=Çiyakani Zagros; Turkish: ''Zagros Dağları''; Luri: ''Kuh hā-ye Zāgro ...

in Iran. The river flows west from the mountains to the city of

Qasr-e Shirin Qasr-e Shirin ( fa, قصرشيرين; also Romanized as Qaşr-e Shīrīn and Qasr-ī-Shīrīn; also known as Ghasr-ī-shīrīn and Ghasr-shīrīn, Kurdish: قەسری شیرین) is a city and capital of Qasr-e Shirin County, Kermanshah Province, ...

, where it turns south and crosses the border with Iraq. It then divides the city of

Khanaqin Khanaqin ( ar, خانقين; ku, خانەقین, translit=Xaneqîn) is the central city of Khanaqin District in Diyala Governorate, Iraq, near the Iranian border (8 km) on the Alwand tributary of the Diyala River. The town is populated ...

in two parts. It has played a significant role in land cultivation and in establishment of a strong rural society in the area, and is considered by the people of Khanaqin as a symbol for their unity and Kurdish identity. The river joins the Diyala River at Zengabadh.

Name

According to

Vladimir Minorsky Vladimir Fyodorovich Minorsky (russian: Владимир Фёдорович Минорский; – March 25, 1966) was a Russian Orientalist best known for his contributions to the study of Persian, Lurish and Kurdish history, geography, ...

, the name "Alwand" is related to the name of the historical city of

Hulwan Hulwan ( fa, حلوان) was an ancient town on the Zagros Mountains in western Iran, located on the entrance of the Paytak Pass, nowadays identified with the town of Sarpol-e Zahab. History Later Arab tradition, as recorded by al-Tabari, co ...

, which lay on the river near the present-day city of

Sarpol-e Zahab Sarpol-e Zahab ( fa, سرپل ذهاب, ''Sarpole Zahâb''; ku, Serpêllî Zehaw, ; also romanized as Sarpol-e Z̄ahāb, Sar-e Pol-e Z̄ahāb, and Sar-ī-Pūl Zūhāb; also known as Pol-e Z̄ahāb, Sarpole-Zahab, Pol-e Z̄ohāb, Sarī-Pūl, and ...

Geography

The Alwand basin is located on the western side of the Zagros and covers an area of about 2,700 km². The climate of this region is semiarid to Mediterranean, with cool winters and dry summers. It receives an average of about 530 mm of rainfall per year. The region is characterized by

karst Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathering-resistant ro ...

terrain, and there are about 35

karst spring A karst spring or karstic spring is a spring (outflow of groundwater) that is part of a karst hydrological system. Description Because of their often conical or inverted bowl shape, karst springs are also known in German-speaking lands as a ''Top ...

s in the Alwand basin (12 major and 23 minor).

Geology

The Alwand basin features seven main

anticline In structural geology, an anticline is a type of fold that is an arch-like shape and has its oldest beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex up in which the hinge or crest is the ...

s, which are separated from each other by

syncline In structural geology, a syncline is a fold with younger layers closer to the center of the structure, whereas an anticline is the inverse of a syncline. A synclinorium (plural synclinoriums or synclinoria) is a large syncline with superimpose ...

s. About 36% of the basin is made up of

carbonate A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonate g ...

formations, primarily the

Asmari Formation The Asmari Formation is a geological formation in western Iran. Located in the western Zagros Mountains, it is a carbonate formation that largely consists of limestone, dolomitic limestone, dolomite, and marly limestone. There are also smaller am ...

. The Asmari Formation, which makes up the main body of the anticlines, consists of Tertiary dolomitic limestone and dolomite. Above it lie layers of the

marl Marl is an earthy material rich in carbonate minerals, clays, and silt. When hardened into rock, this becomes marlstone. It is formed in marine or freshwater environments, often through the activities of algae. Marl makes up the lower part o ...

-and-

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...

Aghajari Formation or the

gypsum Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and drywall. ...

-and-marl Gachasaran Formation. Below it is the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

Pabdeh-Gurpi Formation, which consists of marl and

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...

. Another carbonate formation, the Cretaceous Ilam Formation, is made of limestone and is only exposed in the Patagh anticline. The Asmari Formation, confined beneath the impermeable Aghajari and Gachasaran Formations, is the main

aquifer An aquifer is an underground layer of water-bearing, permeable rock, rock fractures, or unconsolidated materials (gravel, sand, or silt). Groundwater from aquifers can be extracted using a water well. Aquifers vary greatly in their characterist ...

in the Alwand basin.

References

Rivers of Kermanshah Province Rivers of Iraq Landforms of Kermanshah Province Khanaqin {{Iran-river-stub

Name

Geography

Geology

See also

References