Tigris

Overview

The Tigris is a major river of Southwest Asia, approximately 1,850 kilometers long. It rises in Turkey and flows through the heart of Iraq. Together with the Euphrates, it shaped the fertile plains and civilizations of ancient Mesopotamia. The two rivers join before their waters reach the Persian Gulf. Their continued flow supports agriculture, cities and water supplies across Iraq.

Geography

The Tigris crosses northern and central Iraq, passing through Mosul and onward toward Baghdad. Mosul occupies both banks; its historic Old City stands on the western bank. Tributaries add substantial water to the main river. The Little Zab joins the Tigris in Kirkuk Governorate, while the Sirwan joins it south of Baghdad. Together, those tributaries contribute roughly one quarter of the Tigris’s annual flow in Iraq. Their importance extends beyond the places where they meet the river: reduced flows affect agriculture and water quality throughout the basin, including areas near Baghdad.

Farther south, the Tigris and Euphrates converge near Basra. Their combined waters flow through the Shaṭṭ al-Arab to the Persian Gulf. Basra’s position near that outlet makes the condition and volume of upstream water especially consequential for the city. Contaminated water has harmed its residents, while reduced river flows have added pressure to its supply.

Ancient and biblical history

Mesopotamia came to denote the land between the Tigris and Euphrates. Limited rainfall made irrigation from both rivers essential to agriculture, and Iraq’s earliest civilizations developed around the water they supplied. Ancient Babylonia lay between the rivers, approximately within modern Iraq. The Tigris served as a route and a geographic boundary as cities and states developed along its banks. Seleucus I founded Seleucia on the Tigris, and the city grew at Babylon’s expense. In 275 BCE, Antiochus I transferred a substantial Semitic population from Babylon to Seleucia. Mithridates I reached Seleucia in 141 BCE during Parthian expansion.

The river’s ancient names record its place in several languages: Sumerian Idigna, Akkadian Idiglat and Aramaic Diglat. Its Arabic name is Dijla. In Hebrew it is Ḥiddekel. Genesis 2:14 names the Tigris as one of four rivers associated with the Garden of Eden and describes it as flowing east of Ashur. The Tigris and Euphrates are identifiable rivers, but the location of Eden and the identification of all four rivers remain unresolved. Daniel 10:4 places Daniel’s major vision beside the Tigris.

Jewish history

The Targum and Talmud call the river Diglat. Rabbi Ashi interpreted Ḥiddekel homiletically as meaning “sharp and quick.” Talmudic tradition regarded Tigris water as beneficial to body and mind. Because the river appears in the account of creation, a Talmudic ruling instructed Jews who saw it to recite the blessing over the work of creation. In Talmudic times, stretches of the Tigris from Baghdad to Apamea marked a boundary of Babylonia. These references place the river in Jewish biblical interpretation, religious practice and the historical geography of Jewish life in Mesopotamia.

Modern history

The Tigris continued to serve as a geographic reference in modern political plans. The 1920 Treaty of Sèvres used stretches and bends of the river to describe a proposed boundary with Syria. In Iraq, the river remained a defining feature of Mosul and the lands downstream. During the June 2014 crisis in Mosul, Peshmerga forces secured areas east of the Tigris. Islamic State’s seizure of Mosul made the river’s bridges and banks central to the later campaign to recover the city.

Security

During the 2016–2017 battle for Mosul, the Tigris divided the eastern and western fronts. Islamic State, a terrorist organization, used boats to move personnel and equipment between the banks when bridges were unavailable. Iraqi security forces advanced through eastern neighborhoods and seized bridges linking the two sides. On January 15, 2017, the Iraqi Army announced control of 90 percent of the river’s eastern bank in Mosul.

As Iraqi forces approached the end of the eastern operation in January, Islamic State operatives retreated toward a northern Tigris bridge, intending to cross to the western side. US forces destroyed ten Islamic State boats on the river to prevent crossings. Fighting then shifted toward western Mosul and its Old City. In March, Iraqi forces took the Badush area and its dam on the Tigris from Islamic State. Badush Dam regulates Mosul’s water supply. On May 27, Iraqi forces attacked the Old City and three adjoining areas near the river’s western bank. The city’s layout made control of crossings, boats and riverfront neighborhoods consequential throughout the battle.

Present day

Iraq’s water security depends on flows from upstream countries as well as management within Iraq. Turkey’s GAP program includes 22 dams and 19 power plants. Its Ilisu Dam gives Ankara significant control over Tigris water reaching Iraq. Dams in Iran have also reduced flows through major tributaries. Seeking greater releases from Turkey addresses only part of the pressure: the Sirwan and Little Zab are important to the basin, while inefficient irrigation and limited storage compound shortages within Iraq. Reduced Tigris and Euphrates flows associated with Ilisu have added pressure to Basra’s water supply.

The Kurdistan Regional Government operates Dukan Dam on the Little Zab and Darbandikhan Dam on the Sirwan. Iraq’s federal government operates Hemrin Dam on the Sirwan. Steady tributary flows matter to those reservoirs and to agricultural areas farther downstream. Iraq’s environmental organization Humat Dijlah, whose name means “defenders of the Tigris,” has campaigned on the country’s environmental problems. The river also remains a focus of cultural memory for Iraq’s communities, linking the contemporary water crisis with a landscape that has sustained settlement for millennia.