International water law (IWL) providing an underlying legal framework that enables countries to cooperate peacefully and use water resources in a way that maximises shared socio-economic and environmental benefits. IWL comprises international treaties, bilateral and multilateral basin agreements, and principles. This Tool introduces the key universal legal frameworks on transboundary waters, discusses the main governing principles of IWL, and highlights the key mechanisms for facilitating cooperation and dispute settlement.
The use of transboundary water resources requires a legal framework which allows to prevent conflicts, maximise socio-economic benefits, and protect ecosystems. International water law comprises agreements, manifested in rules, treaties and principles (Tool A2.01), that were created to foster cooperation among states sharing freshwater resources. Despite primarily governing inter-State relations, international water law is also relevant and produces impacts on the national legal level. International conventions should be ratified and implemented at the domestic level in order to ensure the compliance of States with norms and principles of international law embodied in such conventions.
Sources of international water law include customary law (Tool A2.03), bi- or multilateral treaties, regional framework treaties and treaties with universal scope of application. There are more than 400 agreements that govern international cooperation on freshwater resources (OSU International Freshwater Treaties Database). The following instruments are considered the universal legal frameworks on transboundary waters:
- Helsinki Rules: One of the first comprehensive codification of the law of international watercourses were the 1966 Helsinki Rules on the Uses of Water of International Rivers (Helsinki Rules), adopted by the International Law Association and regulating “the use of water of an international drainage basin”.
- UN Watercourses Convention: Among the treaties with universal scope of application, the 1997 United Nations Convention on the Law of the Non-Navigational Uses of International Watercourses (UN Watercourses Convention) was the first global convention, which codified international law on transboundary water resources. Despite being adopted in 1997, the Convention entered into force only in 2014, due to due to slow process of ratification.
- UNECE Water Convention: Another framework treaty, the Water Convention on the Protection and Use of Transboundary Watercourses and International Lakes, was adopted in 1992 and entered into force in 1996. Although originally adopted as a regional instrument in pan-European region, it has been opened for accession to all UN Member States in 2016.