An expanding water crisis in Iran that intensified over the past decade is taking its toll on transboundary water resources that lessen downstream Iraq’s share. Thirty percent of the Tigris Basin lies in Iran and the country contributes 10 percent – and according to other estimates up to 13 percent – of its annual water volume. Through a series of tributary rivers, importantly the Little Zab, Karkh, Karun, Alwand, and Diyala, water reaches Iraq. Over the course of a decade, less water has been reaching the Tigris in Iraq from the Iranian side, which is believed to be contributed to sizably by the building of a series of dams on tributary rivers. The toll of reducing water supplies to Iraq is being felt in the country’s southern provinces, several of which in the last few years have seen intensifying anti-government protests over the deteriorated quality of utility service provision.

As drought increases, coupled with a mounting need to cement food security for a growing population under backbreaking sanctions, building dams has been utilized in Iran to increase water preservation, largely an imperative for Tehran to realize strategic goals in the agricultural sector, namely self-sufficiency. There has been a notable increase in dam building on the Iranian side of tributary rivers feeding Iraq since drought increased at the beginning of the last decade. According to a report by Human Rights Watch, in the period between 2011 and 2019, it is estimated that 12 dams were built on the Sirvan river that feeds the Diyala tributary river. Between 2011 and 2017, some 5 dams were built on the Karkh tributary river. In 2012, a mega-dam, Gotvand, was built on the Karun tributary river, which is roughly responsible for 75 percent of Basra’s water consumption. Iran’s dam policy contributed to diminishing the historical marshlands in southern Iraq and of the Shatt Al-Arab river.

Iran’s southwestern province of Khuzestan is the largest contributor to Iran’s agricultural production and the magnitude of production as well as the choice of crop patterns have an impact on downstream Iraq. The agricultural output of the province has been continuously increasing since 2010-2011, rising from approximately 11.05 million tons in the 2010-2011 period to approximately 15.2 million tons in 2016-2017, only to see a decline in the next season to around 12.7 million tons. Based on this author’s calculations, aggregating statistics from Iran’s Ministry of Agriculture Jihad on provincial crop production, the five Iranian provinces bordering Iraq, which are Khuzestan, western Azerbaijan, Kermanshah, Kurdistan, and Ilam, altogether constitute approximately 29.2 percent of Iran’s total crop production.

The increase in agricultural output from provinces bordering Iraq, that produce almost one-third of Iran’s agricultural needs, was likely possible thanks to water preservation and water diversion. Also, Iran is attempting to develop more sophisticated agricultural techniques to maximize its crop production. Improvements in agricultural output overall contribute to Iranian endeavors towards self-sufficiency in food production and food security. Amid a long-term trend of water stress, an increase in agricultural output in provinces bordering Iraq is likely to correspond to less water flow to the downstream neighbor, impacting water availability for drinking and irrigation.

The amount of water Iran can utilize from tributary rivers to the Tigris and via other sources is important for Iran in its long-standing efforts to diversify the economy and increase non-oil export revenue, especially when oil export revenues are very low due to sanctions. Promoting food exports requires increasing production because the size of Iran’s population is itself increasing despite its slow growth rate (at least in the medium-term).

Iraq itself is a key market for Iran’s food exports, along with Afghanistan and the United Arab Emirates. In 2019, Iraq, Afghanistan, and the United Arab Emirates combined were the destination of 52 percent of Iran’s agricultural exports. At least since 2016, Iraq has been the destination of 35 percent of Iran’s agricultural exports, which exceed $2bn in value. Iran needs Iraq to be stable enough to ensure that its exports thrive and even continue to utilize the country as a transit route to send its products to Syria. However, Iran’s water and agricultural policies in the relatively fertile western part of the country could be contributing to the opposite in Iraq: instability.

Drought in Iran had other repercussions on Iraq in the past few years; as hydroelectric production has declined drastically since 2017 with dams storing less water in summers, Iran was not willing to give priority to exporting electricity to neighboring Iraq over covering the needs of its own population. This was the case in 2018, when Iran reduced its electricity supply, indirectly fueling unrest in Basra. It has also been speculated that Iran reduced electricity supply to Iraq in that summer because of payment problems caused by US sanctions. In any case, since 2019 increased rainfall has improved hydroelectric production in Iran and the US has so far provided Iraq with waivers to continue to import electricity from Iran until it can procure electricity domestically or from alternative external sources.

Increased rainfall across Iran and Iraq, as it has been the case since 2019, provides periods of relief that help scale down tensions over transboundary resources. Post-ISIS reconstruction in Iraq is sluggish, but water availability for the agricultural sector remains important for the country’s fast-growing population and internally displaced people (as well as displaced people from Syria). Constant political instability in Iraq hardly allows Baghdad to be in a strong position to negotiate with Tehran on shared water resources.

On the other hand, Tehran is unprecedently hard-pressed by US economic sanctions and concerned about both achieving more self-sufficiency and ramping up agricultural exports to increase non-oil export revenues. This makes it unlikely that Iran will be willing to provide concessions on water resources, at least in the short-term. Yet, Iran should not be scapegoated for all southern Iraq’s water problems and shortages in services, which other upstream neighbors and climate change largely contribute to worsening.