According to an officer of the UN Food and Agriculture Organization, “Each of (Iraq’s) neighboring countries, whether Turkey, Iran or Syria, controls the water flow into Iraq according to its interests, needs and circumstances without adhering to any quota or consideration… The one that pays the price is always the country where the river ends—in this case Iraq.” Iran has recklessly dammed and diverted shared water sources with Iraq for hydroelectricity generation, agricultural use, and drinking water for its own people. This dynamic has had deleterious effects downstream in Iraq.

The Tigris and Euphrates Rivers account for 98 percent of all surface water in Iraq, but the flow of water to these ancient waterways is imperiled by Iran’s activities upstream. Several tributaries originating in western Iran flow to the Tigris River in Iraq, providing up to 25 percent of the Tigris’s mean annual flow. In 1975, Iran and Iraq reached an agreement governing transboundary water flows of the smallest tributaries, but no accord was ever reached on sharing the major tributaries.

With no agreement in place, Iran has set about cutting off or diverting 42 shared rivers and tributaries with Iraq, according to an Iraqi foreign ministry spokesman. Iran has built multiple dams along the Diyala River, the largest tributary feeding into the Tigris in order to divert water to the Iranian city of Kermanshah for drinking, farming, and hydroelectricity. Iran’s damming along the Diyala, as well as the Sirwan and Alwant rivers, has lowered long-term median flows to the Tigris by over 50 percent. An additional dam and inter-basinal water transfer tunnel is in the works to divert waters from tributaries feeding the Tigris to Iran’s southwestern Khuzestan province, which is projected to cut the flow of Iranian waters to the Tigris to just 22 percent of what it would be unimpeded.

The lack of water flows to the Tigris has negatively impacted agriculture and hydroelectricity generation in Iraq, leading to intermittent blackouts. Iran’s Karkheh and Karun rivers feed into Iraq’s Shatt al-Arab River (formed by the confluence of the Tigris and Euphrates), but Iran’s diversion of these tributaries through damming has shrunk the Hoor-Alazim wetlands, which run along the nations’ shared border, to one-third its previous size. The damming has also increased the salinity of the Shatt al-Arab downstream, making it no longer drinkable for Iraqis.

The situation in Basra, at the southern terminus of the Tigris and Euphrates, is especially severe due to the reduced water flows of these two rivers. The Tigris, which crosses through Basra, formerly served as the city’s primary source of drinking and agricultural water. Today, the portion of the Tigris servicing Basra has virtually dried up due to Iranian and Turkish water diversions upstream. The river’s water flow upstream of Basra is no longer sufficient to dilute chemical and industrial pollutants introduced into the stream by Iraq’s petroleum industry. Since July 2018, Basra has faced riots driven in large part by the city’s failing water infrastructure, which has caused a spike in emergency room visits due to water poisoning, skin infections, and intestinal infections.    

Experts have warned that Iran’s reckless policies are engendering drought conditions in Iraq, pointing to the clearly reduced water levels of the Tigris and Euphrates. Iraqi politicians have alleged that Iran’s policies are tantamount to a declaration of war, as they have led to the desertification of over 250,000 hectares of agricultural land and started the process of forcing Iraqis dependent on fishing and agriculture for their livelihoods to migrate from 17 impacted towns and villages. The head of the Iraqi parliament’s committee on agriculture and water has alleged that Iran benefits from undermining Iraq’s agricultural sector, as it forces Iraq to increase its food imports from Iran. Iran’s ability to control Iraq’s water supply gives Iran a key potential source of leverage in its quest to further weaken and expand Iranian influence over Iraq.

Shared river systems have contributed to growing tensions between Iran and Afghanistan as well, although in this instance, Iran is the downstream party in the dispute. Iran views Afghanistan’s growing water demands and water-infrastructure development as a threat to its drought-stricken eastern provinces and has therefore resorted to subversive measures and sabotage to secure the full flow of Afghan rivers into Iran.

Two major rivers that originate in Afghanistan and flow to Iran are the Helmand and Harirud. 96 percent of the Iranian portion of the Helmand and 61 percent of the Iranian portion of the Harirud originate in Afghanistan. A treaty reached in 1973 to ensure sufficient flows to Iran was never fully implemented, derailed by 1979’s Islamic Revolution and Soviet invasion of Afghanistan. Since the fall of the Taliban government, Afghanistan has sought to construct new dams and rehabilitate existing ones for hydroelectric power and irrigation purposes. The dam developments in the works project to drop the Helmand’s flows to Iran “by 2.7 km², equal to half of Iran’s entire water demand in the Sistan basin.” A newly inaugurated dam on the Harirud is expected to cut flows to Iran by 62–76 percent.  

Addressing an international conference in Tehran on combating sandstorms, President Rouhani opposed Afghanistan’s dam plans, warning, “We cannot remain indifferent to what is damaging our environment. The construction of several dams in Afghanistan—the Kajaki, Kamal Khan and Selma dams and other dams in the north and south of Afghanistan—impacts our Khorasan and Sistan and Baluchestan provinces.” Rouhani’s warning was not an idle threat. Iran stands accused of training and arming the Taliban, despite ideological differences, since 2006 as part of a strategy to play all sides against each other in Afghanistan to ensure that any emerging government there will be Iran-friendly, or at least too weak to threaten Tehran’s interests.

In exchange for its support, the Taliban has reportedly endeavored to obstruct dam construction and ensure free flows of water to Iran. Iran has denied such claims, insisting that it only uses diplomacy to settle water disputes with Iran. Afghan officials dispute that assertion, alleging that the IRGC has provided the Taliban with sophisticated weaponry meant to disable offending dams. Iran’s efforts to maintain Afghan water flows go beyond arming terrorist proxies. Iranian border police have repeatedly fired upon Afghan villagers along the Harirud who have sought to divert water from the river in order to ensure clean drinking water. Iranian border police have killed at least ten villagers and reportedly wounded many more.

At the international conference on sandstorms held in Tehran in 2017, former President Rouhani declared without a trace of irony, “The important region of Middle East and West Asia is a family… We must aim at having a more powerful region instead of being the most powerful country in the region.” Iran has a long-term interest in the development of stable governments in neighboring countries such as Iraq and Afghanistan. Working collaboratively through diplomatic channels on water issues could potentially defuse tensions between Tehran and its neighbors and help bring needed stability to Afghanistan and Iraq. Instead, Iran has pursued its narrow, short-term interests, adding drought conditions and water shortages to the combustible mix of problems plaguing the Afghan and Iraqi governments.