When Rivers Run Thin: Why Shared Water Is Becoming a Security Question

In August 2022, satellite images showed the Indus River in Pakistan swelling to more than ten times its normal width, submerging a third of the country. Less than two years later, in early 2024, the same river system was running far below its seasonal average in its upper reaches, triggering emergency irrigation cuts in Punjab. Flood and drought extremes that once defined different eras are now defining the same decade. For the nearly 40 percent of humanity that lives in river basins shared by two or more countries, this volatility is turning a development issue into a security issue.

Water has always been political, but climate change is making it less predictable and less abundant at the moments when it is most needed. Three basins the Indus, the Nile, and the Mekong illustrate how historical treaties, new infrastructure, and a warming climate are converging to test whether water can be managed as a shared resource or will become a source of sustained confrontation.

The Indus: A Treaty Under Strain

The Indus Waters Treaty, signed in 1960 and brokered by the World Bank, is often cited as one of the most durable water-sharing agreements in the world. It survived two wars and multiple crises between India and Pakistan. Under its terms, the three eastern rivers Ravi, Beas, and Sutlej were allocated to India, and the three western rivers Indus, Jhelum, and Chenab to Pakistan, with limited rights for India to develop run-of-the-river hydropower upstream.

The treaty was designed for a different hydrological and political reality. It divides water volumes based on historical flows, with no explicit mechanism for climate adaptation. It also established a complex dispute resolution process involving a Neutral Expert and a Court of Arbitration.

Tensions have centered on India’s hydropower projects in Jammu and Kashmir, such as Kishenganga and Ratle. Pakistan argues that the design of these projects particularly pondage capacity and spillway gates violates treaty restrictions and could give India control over the timing of flows that are critical for Pakistani agriculture, which supports more than 80 percent of the country’s irrigated agriculture and employs a large portion of its workforce. India argues that the projects are within treaty allowances, are necessary for its own energy security and development, and that it has never interfered with Pakistan’s share.

Both governments have sought recourse through the treaty’s mechanisms simultaneously in recent years, leading to parallel proceedings that have raised questions about the treaty’s procedural resilience. Experts note that the underlying driver is not just engineering, but scarcity: glacier retreat in the Hindu Kush-Himalaya, altered monsoon patterns, and rising demand from growing populations on both sides are reducing the margin for error that allowed the treaty to function for six decades.

The Nile: Sovereignty Versus Survival

No river illustrates the clash between national development and downstream vulnerability more starkly than the Nile.

Ethiopia, where about 85 percent of the Nile’s water reaching Egypt originates from the Blue Nile, began construction of the Grand Ethiopian Renaissance Dam, GERD, in 2011. With a capacity of over 5,000 megawatts, the dam is central to Ethiopia’s plan to expand electricity access still below 50 percent in rural areas at the start of construction and to become a regional power exporter. For Addis Ababa, the dam is a matter of sovereignty and economic transformation, financed domestically and built without external funding.

For Egypt, which depends on the Nile for approximately 90 percent of its freshwater, the dam is viewed as an existential risk. A reduction in flow during the multi-year filling period, or during future droughts if filling and operating rules are not agreed, could directly affect agriculture in the Nile Delta and drinking water for over 100 million people. Egypt has therefore insisted on a legally binding agreement on filling and long-term operation, including drought mitigation mechanisms.

Sudan sits between the two, potentially benefiting from regulated flows and cheap electricity, but also concerned about dam safety and its own water needs.

More than a decade of negotiations mediated by the African Union, the United States, and others have failed to produce a binding deal. Ethiopia has proceeded with filling the reservoir, arguing that this is a natural consequence of exercising its right to develop resources within its borders under the principle of equitable and reasonable utilization. Egypt has argued for the principle of no significant harm and historical rights. International water law, primarily the 1997 UN Watercourses Convention, contains both principles, but leaves their balancing to negotiation.

The dispute has remained diplomatic rather than military, despite inflammatory rhetoric at times, and has spurred renewed discussion about benefit-sharing for example, linking power trade to water security rather than zero-sum volume allocation.

The Mekong: Upstream Control

In Southeast Asia, the Mekong River supports the food security of more than 60 million people. Its annual flood pulse drives one of the world’s most productive inland fisheries in the Tonle Sap lake in Cambodia and sustains rice cultivation in Vietnam’s Mekong Delta, which produces roughly half of Vietnam’s rice.

The construction of eleven large hydropower dams on the mainstream of the upper Mekong in China where the river is called Lancang and more than 100 tributary dams downstream, principally in Laos, has fundamentally altered that pulse. Data from the Mekong River Commission, an intergovernmental body of Cambodia, Laos, Thailand, and Vietnam, shows changes in seasonal water levels, sediment transport, and fisheries.

China, which is not a full member of the Commission but a dialogue partner, argues that its dams provide flood control and dry-season flow augmentation, and are essential for its clean energy transition. Data sharing has improved in recent years, with Beijing providing year-round water level and rainfall data.

Downstream countries offer a different perspective. Thailand and Cambodia have raised concerns about unpredictable releases affecting navigation and farming. Vietnam is particularly vulnerable: reduced sediment flow scientists estimate that dams have trapped more than half of the sediment that once reached the delta combined with sea-level rise and groundwater extraction, is accelerating saltwater intrusion and subsidence in the delta. Laos, meanwhile, sees hydropower exports as a core development strategy, often described as the “battery of Southeast Asia.”

The Mekong case highlights a broader institutional gap. Unlike the Indus, it has no comprehensive treaty allocating water among all riparian states. Governance is fragmented between the Mekong River Commission, bilateral deals, and Chinese-led platforms like the Lancang-Mekong Cooperation.

A Changing Climate, A Shared Challenge

Across all three basins, climate change acts as a threat multiplier. The Intergovernmental Panel on Climate Change projects increased variability in the South Asian monsoon, reduced snowpack in the upper Indus and upper Mekong, and higher evaporation rates in the Nile basin. Demand is rising in all three due to population growth, urbanization, and energy needs.

Historians of water conflict note that outright “water wars” interstate wars fought primarily over water remain rare. The more common pattern is subnational conflict, political leverage, and prolonged diplomatic stalemate. The risk is not that water alone causes war, but that it intensifies existing rivalries and makes cooperation harder to sustain.

What makes the current moment different is the scale of infrastructure and the speed of environmental change. The treaties that prevented conflict in the 20th century were based on stationarity the idea that future flows would resemble past flows. That assumption no longer holds.

Preventing water from becoming a security crisis will require updating that legal and institutional infrastructure: more transparent, real-time data sharing; agreements that allocate benefits such as power and flood control rather than just volumes; drought contingency rules that are triggered automatically; and inclusion of local communities who are often the first to experience scarcity.

Rivers do not respect borders. Whether they become fault lines or lifelines will depend on whether countries that share them can agree on rules that are as adaptable as the climate they now face.

*An accomplished jurist with profound acumen in constitutional and corporate jurisprudence, advising both public institutions and private enterprises, and shaping contemporary legal and policy thought.