International Law International Watercourses
Patricia Wouters
  • LAST REVIEWED: 20 November 2020
  • LAST MODIFIED: 23 March 2012
  • DOI: 10.1093/obo/9780199796953-0064


The rules of international law governing transboundary waters are anchored in the rules and practice of public international law. The UN Charter’s provisions calling for the maintenance of international peace and security, as well as the promotion of international cooperation and the fundamental freedoms of all, have a direct bearing on the law that governs the world’s transboundary waters. Thus, a study in this particular field must begin within the context of the law of nations. International water law, used here as a catchphrase to refer to the international treaty norms and customary rules that apply to the fresh waters shared by two or more nation-states (transboundary watercourses), has evolved into an identifiable body of rules and practices over the past half-century. While early concerns related mostly to boundary delimitation and navigation, current challenges relate to development needs (including poverty alleviation and the needs of the most disadvantaged), environmental requirements, and the growing uncertainties on a number of fronts (i.e., climate change, ecosystem services, sustainability, and so forth). As with all things international, state sovereignty plays an important role, despite the fact that transboundary rivers, lakes, and aquifers, in their normal state, ignore national borders, preferring instead the calls of nature. More than three hundred major international watercourses traverse two or more sovereign states, and several important river basin and groundwater systems link entire regions, thus presenting complex challenges. This field of study is enriched by a vast and growing body of literature (from the private and public sectors), including significant contributions by the UN, which has some twenty-seven publications that deal with laws concerning water. However, at the heart of this topic is the practice of states, within and beyond their national borders, since national development policies often are linked to water resources management; consequently, national water law and policy should be reviewed as part of the transboundary watercourses research remit.

Introductory Works

There are a number of introductory works, beginning first with the Charter of the United Nations and Statute of the International Court of Justice, which provides the context for research in this field. Given the UN’s significant involvement in supporting the peaceful management of the world’s transboundary waters, consideration should be given to its relevant work, including policy statements on regional peace and security. In this regard, Annan 2005 is most useful, since it sets forth a compelling case for increased international cooperation across the barriers of state sovereignty—an approach that supports scholarship in this area. Other important UN publications include the Hashimoto Action Plans I and II, adopted by the UN Secretary-General’s Advisory Board on Water and Sanitation, and the World Water Development Report, published every three years, which presents a collective UN update on key issues in this field. United Nations 2009 offers a comprehensive examination of current water-related issues, with specific references to transboundary waters, but also provides a worldview. Locating transboundary water law within a broader context, such as the law of nations, is provided in Annan 2005; situating water law within a global policy discourse is offered in Solanes and Gonzalez-Villarreal 1999. Wouters and Hendry 2009 places the discussion within the broad domain of water law and provides a good introduction to some of the current topics in the field, showing how international water law interfaces with national water law.

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