The UN Watercourses Convention is a global international treaty (specifically, a framework convention) titled the Convention on the Law of the Non-Navigational Uses of International Watercourses. It was adopted by the United Nations on 21 May 1997 and entered into force on 17 August 2014, seventeen years later, to provide a universal legal framework for managing shared freshwater resources. It addresses the problem that over half of the world’s available freshwater is shared by multiple nations, aiming to promote cooperation and prevent conflicts.
The Convention works by establishing a set of principles for states sharing an international watercourse, which is defined to include both surface and groundwater. Its cornerstone is the principle of equitable and reasonable utilization and participation (Article 5), which requires a state to use the watercourse in a manner that is fair and reasonable vis-à-vis other sharing states. This is balanced by the second key principle: the obligation not to cause significant harm (Article 7) to other watercourse states. The mechanism also requires states to exchange data and information and provide prior notification of planned measures.
The Convention connects to the regional UNECE Water Convention (adopted in 1992) and has influenced international jurisprudence, notably the International Court of Justice's judgment in the Gabčíkovo-Nagymaros Project case (1997). India, which shares several major rivers, abstained from the vote and has not ratified the Convention. India’s objection partly stems from the concern that Article 3, which allows for watercourse agreements, could conflict with its domestic law where water is constitutionally a state subject. The Convention itself has not been replaced or amended since its adoption.