MENA Water Review · Visual story
Iraq’s Shrinking Lifelines: How Dams and Drought Are Drying the Tigris and Euphrates
The Tigris and Euphrates watered some of the world’s first cities, its earliest known law codes and some of its oldest irrigated fields. Six thousand years later, the rivers that made civilisation possible are carrying less and less water.
Four countries share the two rivers. There is no agreement between them all.
Two rivers rise in the mountains of eastern Turkey. They run south on either side of a single flood plain before meeting in southern Iraq, where they form the Shatt al-Arab and empty into the Gulf. Between them lies Mesopotamia, a Greek name meaning “the land between the rivers”. This is the plain where some of the first cities and the first writing system emerged.
The Euphrates is the longer of the two rivers. The Tigris is shorter, less meandering and carries more water. About 89% of the Euphrates’ flow is generated in Turkey. The Tigris draws more evenly on tributaries in Iraq and Iran. This geography determines the modern story of the rivers: the water is generated in the mountains and used on the plain.
Most of the water rises in the mountains, and most of those mountains are in Turkey.
In a 1987 protocol, Turkey undertook to release an annual average of at least 500 cubic metres per second across the Syrian border. In 1990, Syria and Iraq agreed to divide the river, with 42% going to Syria and 58% to Iraq. But no agreement binds all the riparian states. The pledged annual average, about 16 billion cubic metres a year, is roughly half the 30 billion that crossed the border before 1973. As less water arrives from upstream, the Shatt al-Arab can no longer hold back the sea. Salt water therefore intrudes up the river towards Basra.
Interactive: choose a step, or use the arrows, to change the figure
The Euphrates rises in Turkey and crosses Syria; the Tigris rises in Turkey, follows part of the Syrian-Turkish border, and joins the Euphrates in southern Iraq to form the Shatt al-Arab.
About 89% of the Euphrates’ flow is generated on Turkish soil, which is why a dam near the source is felt in Basra. The Tigris draws more evenly on tributaries in Iraq and Iran.
Turkey’s GAP project was planned around 22 dams across the headwaters of both rivers. Syria dammed the Euphrates at Tabqa, Iraq built the Samarra barrage, and Iran dammed Tigris tributaries.
Less water now crosses the border than before 1973, and the weakened Shatt al-Arab cannot hold back seawater coming up the estuary towards Basra.
Notes
Map: country borders from Natural Earth; river lines from the free-flowing rivers network of Grill et al. (2019); dam and city positions from the MENA Water Review country map kit. The shaded area in step 2 is Türkiye, where about 89% of the Euphrates’ flow is generated. The Diyala marker shows the river’s headwaters in Iran rather than a single dam.
Share of each river’s water that originates in Turkey
Notes
Estimates. Measured water-balance data are lacking for the Tigris, so the range is wide, and the balance comes from tributaries in Iraq and Iran.
Hammurabi’s Code already fixed who must keep which dam in repair.
For the people who first settled beside them, the two rivers were part of religious belief as well as agriculture. Cuneiform texts show how the marshes where the rivers meet shaped the region’s religious beliefs, rituals and literature. The Book of Genesis describes a river flowing out of Eden and dividing into four branches. It names two of them as the Hiddekel, meaning the Tigris, and the Euphrates. On this same flood-prone plain, Babylonian scribes recorded some of the oldest surviving stories of a great deluge. The flood story also appears in the eleventh tablet of the Epic of Gilgamesh.
The rivers flooded violently and unpredictably, but they also carried fertile silt. Watered by canals and properly drained, the fertile soil of the south could feed a large population. Achieving this collectively and at scale was arguably a founding act of civilisation, and it required rules. Hammurabi’s Code, set down in Babylon under a king who reigned from 1792 to 1750 BCE, already specified who had to keep which dam in repair and who owed whom compensation for a flooded field.
Downstream, in the wetlands where the rivers braid together, the Ma‘dan, the Marsh Arabs, build villages on islands of reed and mud. They live from fish, rice and water buffalo in marshes that people have inhabited for more than five millennia.
- c. 5000 BCE
The first canals
At Choga Mami, on the plain’s eastern edge, farmers of the Samarra culture dig irrigation ditches, probably fed by a canal from the foothills. Large-scale irrigation later sustains the cities of Sumer, among them Uruk, Ur and Eridu.
- c. 1750 BCE
Water, written into law
Hammurabi’s Code sets penalties for neglecting a dam and for flooding a neighbour’s field.
- for 5,000 years
The Marsh Arabs
People have lived in the marshes for more than five millennia; the Ma‘dan build reed houses on artificial islands. About half a million live there in the 1950s.
- 1950s–70s
The age of the barrage
Iraq diverts Tigris floodwater at Samarra from 1954, and Turkey’s Keban Dam (1974) and Syria’s Tabqa Dam (1975) follow on the Euphrates. Regulation flattens the rivers’ natural seasonal flood.
- 1977–1992
The GAP transforms the headwaters
Turkey launches its Southeastern Anatolia Project across the sources of both rivers in 1977. The Atatürk Dam on the Euphrates, its centrepiece, is completed in 1992.
- 2020
Ilısu at full power
Turkey’s Ilısu Dam on the Tigris reaches full generating capacity. It sits at the heart of a planned reservoir system to regulate the second river.
In 2018, 118,000 people or more were hospitalised in Basra as a result of the water crisis.
Upstream in Turkey, the GAP project was planned around 22 dams and 19 hydropower plants across the headwaters of both rivers. Syria dammed the Euphrates at Tabqa, while Iran dammed Tigris tributaries such as the headwaters of the Diyala. The states above the plain now store, measure and release the water. The plain no longer controls how much water reaches it.
The consequences are felt at the bottom of the system. In 2018, reduced flows from upstream raised the levels of sewage, pollution and salt in the water, and 118,000 people or more were hospitalised in Basra. A city at the mouth of two great rivers could not supply its own population with water that was safe to drink.
The marshes shrank from as much as 20,000 square kilometres to a small fraction, then partly came back.
The consequences are most evident in the wetlands at the end of the system. After the Gulf War and the unrest of 1991, a massive engineering programme by the Iraqi government drained the marshes, on top of the effects of upstream damming. By 2000, the Central and Al Hammar marshes had lost more than nine-tenths of their land cover to bare earth and salt crust. The Ma‘dan population fell from about half a million in the 1950s to around 20,000. UNEP called the loss one of the world’s greatest environmental disasters.
After 2003, the water returned. Iraqis broke open the dikes and canals that had drained the marshes. By 2006, a UNEP assessment found that about 58% of the mid-1970s marsh area had been restored, judged by standing water for part of the year and fairly dense vegetation. Separate field research by Iraqi and American scientists found fish and birds re-establishing. Many Marsh Arabs returned too. UNESCO inscribed the Ahwar of Southern Iraq as a World Heritage site in 2016.
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The marshes covered an estimated 15,000 to 20,000 square kilometres in 1970, fed by the seasonal flood of both rivers.
Drainage works and upstream damming reduced the Central Marshes to 3% of their 1973 to 1976 extent and Al Hammar to 6%, leaving bare earth and salt crust.
Iraqis broke open the dikes and canals, and water flowed back into the basins.
A UNEP assessment found about 58% of the mid-1970s area restored. Satellite records show major losses of water and vegetation again in 2022 and 2023, linked to upstream drought, dam operations and water policies.
Notes
Rivers and borders are mapped; the marshes are not. Each marsh is drawn as a simple shape centred on its published position (Ramsar site 2241 for the Central Marshes; between the West and East Hammar Key Biodiversity Areas for Al Hammar), and its area, not its width, carries the share. The dashed outline is the mid-1970s extent. Marsh extent varies with river inflows, which are affected by upstream precipitation and water management.
The recovery is fragile because the water that refills the marshes is the same water that everyone upstream now wants. Satellite records show major losses of water and vegetation again in 2022 and 2023, linked to upstream drought, dam operations and water policies. Restoration here is therefore not a one-off achievement; it has to be secured again in every dry season.
Mesopotamian marshland, share of the mid-1970s extent
Notes
The first bar is the 1973 to 1976 mapped extent of the marsh units; the 15,000 to 20,000 km² often given is the estimate for 1970. The 2000 figures compare each marsh with its 1973 to 1976 extent; the 2006 figure is UNEP’s assessment of restored area across all the marshes.
The room to manoeuvre is no longer in the volume of water. It is in how it is used.
There is still no agreement binding Turkey, Syria, Iraq and Iran to a shared allocation of the two rivers. There are bilateral protocols, as well as discussion of a joint technical committee that goes back to 1964. Iraq and Turkey signed a Water Cooperation Framework Agreement on 22 April 2024 and, on 2 November 2025, a financing mechanism under which Turkish companies are to build Iraqi water projects, paid for through a system based on Iraqi oil sales. Climate change has already made multi-year drought in the basin more severe.
Agriculture took 92% of Iraq’s water withdrawals in 1990 and still about three-quarters in 2022. The World Bank found that Iraq’s irrigation was built around flooding fields. Perhaps half of the diverted water was actually used by crops, and possibly as little as a quarter. The World Bank called better irrigation efficiency the least expensive way for Iraq to increase supply, and it is within Iraq’s own control.
More efficient irrigation could extend the remaining supply considerably. So could a basin-wide agreement among all four riparian states. No such agreement yet exists.
Images via Wikimedia Commons: Mesopotamian marshes near Nasiriyah © Montzr (CC BY-SA 4.0); Great Ziggurat of Ur © Alli Khalil (CC BY-SA 4.0, cropped); Atatürk Dam © Bernard Gagnon (CC BY-SA 3.0).
Sources
26 references
Ancient dates are approximate, and river and marsh figures vary from year to year. The rivers and borders on both maps are mapped; the marsh shapes are symbols, not mapped outlines.
- UNESCO World Heritage Centre, The Ahwar of Southern Iraq, inscribed 2016 (archived listing).
- Encyclopaedia Britannica, “Cuneiform law” (archived August 2019).
- Oriental Institute, University of Chicago, “Excavations at Choga Mami, Iraq”, Annual Report 1967–68 (archived; the institute’s live copy has been withdrawn).
- UN-ESCWA and BGR (2013), Inventory of Shared Water Resources in Western Asia, chapter 1: Euphrates River Basin.
- UN-ESCWA and BGR (2013), Inventory of Shared Water Resources in Western Asia, chapter 3: Tigris River Basin.
- Encyclopaedia Britannica, “History of Mesopotamia” (archived January 2023).
- Southeastern Anatolia Project (GAP), official project website, retrieved September 2026.
- Human Rights Watch (2019), Basra is Thirsty: Iraq’s Failure to Manage the Water Crisis, 22 July 2019.
- UN-ESCWA and BGR (2013), Inventory of Shared Water Resources in Western Asia, chapter 4: Shared Tributaries of the Tigris.
- Natural Earth, 1:10m cultural vectors, admin-0 countries (public domain): country borders on both maps.
- Grill, G., Lehner, B., Thieme, M. et al. (2019), “Mapping the world’s free-flowing rivers”, Nature 569: 215–221, dataset doi:10.6084/m9.figshare.7688801 (CC BY 4.0): river lines on both maps.
- Genesis 2:10–14, Hebrew text and English translation via Sefaria.
- Center for Online Judaic Studies, “Gilgamesh Epic: The Flood Story”, retrieved September 2026.
- Partow, H. (2001), The Mesopotamian Marshlands: Demise of an Ecosystem, UNEP DEWA/GRID-Geneva.
- Musée du Louvre, collection record: Code de Hammurabi stele.
- Avalon Project, Yale Law School, The Code of Hammurabi, translated by L. W. King.
- UN Environment Programme, “Crunch time for Iraqi marshlands”, Nairobi, 28 June 2016.
- Daily Sabah, “Turkey’s Ilısu Dam on Tigris starts generating energy at full capacity”, 24 December 2020.
- Alqaraghuli, A. et al. (2026), “The impact of climate factors and surface water management on the Mesopotamian Marshes for the period 2000–2023”, Scientific Reports 16, 32083, doi:10.1038/s41598-026-61808-9, published 15 July 2026.
- NASA Earth Observatory, World of Change: Mesopotamia Marshes, retrieved September 2026.
- Ramsar Sites Information Service, Central Marshes, site no. 2241, coordinates 31°10′34″N 46°59′E, retrieved October 2026.
- Key Biodiversity Areas, site factsheets West Hammar (32102) and East Hammar (32099), retrieved October 2026.
- Altun, T. and Solmaz, F.Z., Anadolu Agency, “Türkiye, Iraq sign financing mechanism to advance water cooperation projects”, 2 November 2025.
- World Weather Attribution, “Human-induced climate change compounded by socio-economic water stressors increased severity of 5-year drought in Iran and Euphrates and Tigris basin”, 21 November 2025.
- World Bank (2006), Iraq: Country Water Resource Assistance Strategy, Report No. 36297-IQ, 30 June 2006.
- World Bank, World Development Indicators, Annual freshwater withdrawals, agriculture (% of total freshwater withdrawal), Iraq (ER.H2O.FWAG.ZS, from FAO AQUASTAT), retrieved October 2026.
Every figure and claim in this story rests on the references above. The stories list them here rather than marking them in the text; the country reports and hubs keep their inline markers.