International water law is the system of laws that regulate the use and management of water resources, primarily rivers, which cross boundaries between countries — known as transboundary resources. Several different international organizations create and arbitrate different aspects of international water policies. Many, but not all, of the worlds 263 transboundary rivers are governed by some type of international water law.
Several branches of the United Nations (UN) have considered international water law since the organization's formation. The UN General Assembly passed several resolutions on shared natural resources during the 1970s. A water conference and a conference on the human environment were held by the UN during the same time period. More recently, the United Nations Conference on Environment and Development considered how to develop and manage transboundary water resources to protect quality and supply.
The Convention on the Law of the Non-navigational Uses of International Watercourses, which took place in 1997 and was adopted by the UN General Assembly, is probably the most comprehensive agreement in international water law. This convention considered surface water and groundwater bodies shared by two or more countries. The convention required "equitable and reasonable utilization and participation" from the countries involved, and also specified obligations to cooperate, not cause significant harm, and share data about the transboundary resources. It also gave countries sharing a watercourse joint responsibility in controlling pollution and protecting the environment.
Recommendations on pollution and other environmental concerns in transboundary waters have also been put forth by the Organization for Economic Co-operation and Development (OECD). The International Conference of Water and the Environment, held in 1992, considered methods for resolving conflicts arising due to transboundary water resources. There are also several regional inter-governmental organizations that consider transboundary waters in their respective regions, such as the Council of Europe, the Pan-American Union, and the Asian-African Legal Consultative Committee.
Non-governmental international law associations also consider the various difficulties arising from transboundary water resources. The International Law Association adopted a set of rules, called The Helsinki Rules on the Uses of the Waters of International Rivers, in 1966, and has periodically added rules and articles to The Helsinki Rules since that time. Resolutions and regulations concerning navigation and pollution of international waters have been made by the Institute of International Law. The International Association for Water Law and the Inter-American Bar Association have also made recommendations concerning transboundary waters.
A few international courts are responsible for the resolution of disputes concerning transboundary waters. The Permanent Court of International Justice and the International Court of Justice have ruled on international water law cases. An arbitral tribunal is responsible for settling cases involving arbitral awards.