Ecostani: India walking out of the Indus Waters Treaty and its hydrological impact

Climate change has already reduced water flow in Indus; suspension of the Treaty would hit at least three big hydro projects and agriculture in Pakistan.

In 1995, World Bank vice president Ismail Serageldin warned that “wars of the next century will be fought over water.” Thirty years later, his prediction has almost come true in one of the world’s most volatile regions — Kashmir.

The Baglihar Hydroelectric Power Project built on the Chenab river. (ANI Photo)

On April 24, 2025, India announced that it would downgrade diplomatic ties with Pakistan over an attack by terrorists in Pahalgam in Kashmir that killed 26 tourists and suspended the Indus Waters Treaty – a decades-old agreement that allowed both countries to share water use from the rivers that flow from India into Pakistan.

Pakistan has promised reciprocal moves and warned that any disruption to its water supply would be considered “an act of war.” Pakistan has decided to suspend the Simla agreement that provided for border management between the two countries.

The Indus River has supported life for thousands of years since the Harappan civilisation, which flourished around 2600 to 1900 BCE in what is now Pakistan and northwest India. After the partition of India in 1947, control of the Indus River system became a major source of tension between India and Pakistan.

Disputes arose almost immediately, particularly when India temporarily halted water flow to Pakistan in 1948, prompting fears of the collapse of the farm sector.

These early confrontations led to years of negotiations, culminating in the signing of the Indus Waters Treaty in 1960, brokered by the World Bank. The agreement divided the Indus Basin between the two countries, giving India control over the eastern rivers – Ravi, Beas and Sutlej – and Pakistan control over the western rivers: Indus, Jhelum and Chenab, the three rivers mainly flowing from Kashmir.

When the agreement was signed, India’s population was 436 million, and Pakistan’s was 46 million. Today, those numbers have surged to over 1.4 billion and 240 million, respectively. The increase in population has increased pressure on the precious water source even though the water flow in the rivers is unstable on the account of reduction in the annual snowfall and erratic monsoon rains.

The World Meteorological Organisation reported that 2024 was globally the driest year in over three decades and International Centre for Integrated Mountain Development (ICIMOD) studies have found that Hindu Kush-Karakoram-Himalayan glaciers — main water source for Indus — melted 65% faster in 2011–2020 compared with the previous decade.

In April 2025, ICIMOD said that the Hindu Kush-Karakoram-Himalayan including mountains that feed water into Indus rivers had lowest snow persistence — fraction of time snow is on the round after snowfall — of 16.9% in the previous winter, lowest in the past 13 years.

“Carbon emissions have already locked in an irreversible course of recurrent snow anomalies in the HKH,” said ICIMOD director general, Pema Gyamtsho. The ICIMOD studies have shown slowing down of annual snowfall in the region since 2016.

According to studies, the upper Indus carries about 110 cubic km — slightly less than half the total supply of water in the Indus river system. The Jhelum and Chenab combined carry roughly one-fourth, and the Ravi, Beas, and Sutlej combined constitute the remainder of the total supply of the system.

Almost one-fourth of the annual water the rivers in the Indus basin receives is from snow melt and rests from rains, mostly during monsoon from July to September. In summers, the snow melt accounts for 60-70% of water flow into the Indus rivers.

ICIMOD said that deficit of seasonal meltwater, in general, means lesser river runoffs and early-summer water stress, especially for downstream communities, already reeling under premature and intensifying heat spells across the region.

The annual rainfall in the basin ranges between 110 mm to 500 mm and most areas in basin, especially in Pakistan are very dry, and Indus water is the main source of water for living and agriculture.

Heavy deforestation in several provinces in Pakistan such as Punjab and Sindh have led to increase in desertification even though Punjab province has a good network of irrigation canals.

Extensive use of ground water that accounts for nearly about 48% of the water withdrawals in the Indus Basin has led to a drop in groundwater levels and a further loss of vegetation with natural forest replaced with thorn forests of open acacia and bush and undergrowth of poppies, vetch, thistles, and chickweed, studies have shown. Apart from sustaining agriculture, the Indus rivers are also source of fish varieties such as Hilsa and Himalayan Trout.

Following promulgation of the 1960 treaty, the Pakistan Water and Power Development Authority built several linking canals and barrages to divert water from its western rivers to areas in the east lacking water.

The biggest of those canals is the Chashma-Jhelum link joining the Indus river with the Jhelum River, with a discharge capacity of some 21,700 cubic feet (615 cubic meters) per second. Water from that canal feeds the Haveli Canal and Trimmu-Sidhnai-Mailsi-Bahawal link canal systems, which provide irrigation to areas in southern Punjab province.

The Indus Waters Treaty also made provision for the construction of two major dams in Pakistan. The Mangla Dam on the Jhelum River near the town of Jhelum is one of the largest rolled earth-fill dams in the world. Mangla Reservoir, created by the dam, is 64 km long and has a surface area of 260 square km.

The second gigantic project is the Tarbela Dam on the Indus, 80 km northwest of Rawalpindi. The dam’s electricity generating capacity is some three times that of the Mangla Dam, and its total potential is considerably greater.

A third major structure, completed in 2004, is the Ghazi Barotha hydroelectric project, located below Tarbela. The Indus is partially diverted there to a powerhouse that can generate 1,450 megawatts.

Experts said that India’s suspension of the Indus Water Treaty would impact all major hydro projects in Pakistan apart from reducing water flow into the country, impacting its agriculture as it happened in 1948.

On the other hand, they said it could improve Kashmir’s agriculture and hydrological potential as the treaty restricts use of water resources of rivers flowing from the state of Jammu and Kashmir. Only 19.8% of the hydrological potential of western flowing Indus rivers in India has been utilised, according to a study by Jal Shakti ministry.

India’s hydropower projects in Kashmir — such as the Baglihar and Kishanganga dams — have been a major point of contention. Pakistan has repeatedly raised concerns that these projects could alter water flows, particularly during crucial agricultural seasons. The Kishanganga and Ratle dam disputes, now under arbitration in The Hague.

In September 2024, India formally called for a review of the Indus Waters Treaty, citing demographic shifts, energy needs and security concerns over Kashmir. The World Bank had admitted India’s petition and agreed to hear its concerns despite protest by Pakistan.

The suspension of the treat is subject to decisions of the Permanent Court of Arbitration (PCA) or International Court of Justice, which can be long drawn process. If the verdict comes in India’s favour, walking out of the treat would be a win-win situation for northwestern India.