Transboundary water disputes are common among states that share the same sources of water. The relationship between Afghanistan and Iran over the decades is plagued by many factors, one of them being the clash over the division of the Helmand(or Hirmand) River. The River is 1,150 km long, which originates in the mountains of the Hindu Kush near Kabul, the capital of Afghanistan. It travels southwest and enters into Sistan Depression on the Iran-Afghan border before reaching the Hamoun Lake.

It holds significant importance for both the neighbors as its basin irrigates 80 percent and 90 percent of the land in southeastern Afghanistan and Sistan-Baluchistan, respectively. In May 2023, the military tension escalated when both sides exchanged heavy fire, leading to the killing of two Iranian and one Afghan guard, with many injured. The incident was the result of the exchange of hostile statements between the leadership of two countries over the water issue.

“Iran will have to provide oil in exchange for water from Afghanistan,” President Ashraf Ghani declared at Kamal Khan Dam’s inauguration.

The former Iranian President Ibrahim Raisi had warned the Taliban government during a visit to the Sunni majority province of Sistan-Balochistan that Afghanistan should not withhold the water rights of the people of Iran. He emphasized that the Iranians should be provided with their due share of Helmand River water. In response, the Taliban government said that the Iranian leadership needs to choose their words wisely. In the following week after the exchange of these statements, the military tension was built up with the potential of transforming into full-scale war. In the past, the two neighbors have exchanged such statements over the water issue. However, this time it was also accompanied by a military standoff.

The water issue between the two countries can be traced back to the 19^th century. The political tension between the Persian Empire and Afghanistan escalated when 440 km of land of Afghanistan, located at the borderline of the Helmand River, was occupied by the Persians. The King of Afghanistan, Sher Ali Khan, placed the request before the British Empire to resolve the situation. The British officer General Frederic Goldsmid drew the boundary line between the two countries in 1872. Following this division, the water tension between both countries has resulted in sour bilateral ties. In the year 1939, a treaty was finalized to resolve the water issue.

However, it was never ratified by the Afghan government. The issue intensified when Afghanistan started building dams on the Helmand River in the 1950s, Arghandab and Kajaki, funded by the United States. A long period of negotiations over the years resulted in the ratification of the Helmand Treaty in 1973 by Iran and Afghanistan. According to the treaty, Afghanistan is bound to provide Iran with 26 cubic meters of water per second in a normal water year. However, both sides have accused each other of not honoring the treaty. The River holds immense importance for both countries. More than 80 percent of the land water requirement for both southeastern Afghanistan and Iran’s Sistan-Baluchistan province is fulfilled by the Helmand River basin.

The period following the 1973 treaty was accompanied by war, displacement, mismanagement of water allocation, droughts, and climate change, which further complicated the issue. It is argued that Iran took advantage of turmoil and unrest due to the Soviet invasion in Afghanistan and built an extensive system of irrigation, including dams, reservoirs, canals, and water pumps to store water on the lower part of the Helmand River. On the other hand, Afghanistan also started the construction of the Kamal Khan dam in 1974, which was completed in March 2021. President Ashraf Ghani made the completion of the dam project a priority in his regime. In the inauguration speech of the dam, he declared that Iran would have to provide oil in exchange for water from Afghanistan.

The Helmand River irrigates 80% of southeastern Afghanistan and 90% of Iran’s Sistan-Baluchistan province.

The construction of water structures by both countries has been perceived as a violation of the treaty by the other. The Hamoun wetland, located in Sistan-Baluchistan, irrigated by the Helmand river, is of utmost importance to the local communities as their livelihoods, including agriculture, animal husbandry, and fishing, depend on water provided by natural resources. However, over the years, due to droughts, climate change, and population increase, the wetlands have significantly dried up.

The desertification of the wetlands has raised concerns for local communities, for which Iran blames the construction of the Kamal Khan dam in Afghanistan. It is alleged that Afghanistan has built the dam to divert flow to the Gowd-e-Zeran wetlands instead of providing Iran with its due water share. The transboundary water problem of Iran and Afghanistan is a matter of sustainable development, which should be resolved via cooperation. Unfortunately, the national interests of both states have turned this matter into a political issue.

The border clashes between the two countries are very common. Both neighbors blame each other for starting the escalation, but the matter eventually settles down. Following the same pattern, the two neighbors exchanged heavy gunfire on May 27 at the frontier of Afghanistan’s Nimroz province, which was eventually resolved through diplomatic means. Tension escalated so much that tanks were deployed at the border by Afghanistan. Meanwhile, Iran also closed the Milak-Zaranj border post, which is an important point for commercial crossing.

The standoff was the result of verbal sparring between the leadership of both countries in the week preceding the clash. In response to the late President Raisi’s statement urging the Taliban to give Iranian citizens their due share of water, a Taliban commander shared a video mocking the President with a bucket in his hand, saying that the Taliban are not afraid of attack from Iran. The resulting military standoff was followed by a phone call between Iranian Foreign Minister Hussain Ameer Abdullahian and the acting Foreign Minister of the Taliban government, Amir Khan Muttaqi. During the conversation, the Iranian minister asked his Afghan counterpart to open the Kajaki dam. Meanwhile, Muttaqi claimed that even if the dam is opened, there is not enough water that would be sufficient for both countries.

In May 2023, border clashes killed guards on both sides following hostile statements over water access.

The Taliban and Iran had bitter-sweet relations in the past. Iran is accused of providing intelligence to the United States about the location of the Taliban in Afghanistan. Later, the Taliban were used as a proxy group by the Iranian government to help destroy water structures in Afghanistan. From 1998 to 2001, during the first government of the Taliban in Afghanistan, the sluices of Kajaki dam were closed, hindering the free flow of water to Iran. In the Taliban’s second government, the clashes continue, as well as the war of rhetoric between the two countries.

On Jun 10, 2025, the Iranian officials accused the Taliban of not making any efforts to meet their obligations under the Helmand treaty. The Taliban, on the other hand, maintain that they have been fulfilling their “obligations within the framework of regional norms and international law.” The mutual stakes have forced the two to maintain cooperative relations over the years. One such stake is the threat of hardliner terrorist group Daesh Khorasan, also known as Islamic State of Khorasan Province(ISKP), which is a common enemy to both Iran and the Taliban. The return of Afghan refugees to the country has put more pressure on the country’s economy and natural resources.

As far as the question of winning and losing is concerned, there is no clear answer. In the border clash of May 2023 between Iran and Afghanistan, there were military and civilian casualties on both sides. Moreover, people have been dying due to drought and water scarcity in both countries. At least 90 percent of the population of Iran is already suffering from drought. The combination of dust storms and floods has also made living unbearable in Sistan-Baluchistan Province.

The recurring droughts in Afghanistan have also forced thousands of people to migrate and leave their homes in search of clean water. According to an estimate, only 42 percent of the population in Afghanistan can access safe water. The increasing climate change, combined with the mismanagement of water in Afghanistan, is impacting not only Afghans but also Iranians. Moreover, Iran, to build pressure on the Afghan Taliban, has threatened to send back the refugees who fled the war and social unrest in Afghanistan. In the war of rhetoric between the countries, it is the common people who are ultimately suffering.

The border clash of May 27 was eventually resolved through diplomatic talks. Since then, there has been no significant military escalation. However, the two neighbors continue to exchange spiteful rhetoric over the water issue. Iranian authorities still claim that there is no flow of water from Afghanistan to Iran. Meanwhile, the de facto Taliban government reasserts that there is no water available to share with the neighbors due to the climate crisis and drought.

In the past and even today, the Iranian government requests that Afghanistan grant permission to send an inspection team to measure the water level in the Helmand River, which Afghanistan continuously denies. In January 2024, Iran closed its borders with Afghanistan as well as Pakistan after a terror attack was conducted by ISKP in the southeastern city of Iran, which claimed the lives of 89 people. The trust crisis between the two countries continues to impact the relationship and hinders cooperation.

The water issue between Afghanistan and Iran is one and a half centuries old. However, its coinciding with a military escalation is a matter of grave concern for the two neighbors as well as the whole region.  Iran and Afghanistan should sit together to solve the matter. There is a dire need to revise the Helmand Treaty of 1973 according to the current water level in the river.

Iran continues to request inspection access to Helmand River water levels, which the Taliban government denies.

A joint water commission should be developed to oversee the distribution of water in accordance with the revised treaty. The most important factor that needs to be addressed is climate change, which cannot be resolved without cooperation. The failure of the Helmand Treaty lies in the fact that both sides lack the political will due to the trust deficit in the other party. For this particular reason, mediation by a third party might be more reliable to resolve the issue.

Disclaimer: The opinions expressed in this article are solely those of the author. They do not represent the views, beliefs, or policies of the Stratheia.