Page 366
environmental matters. The problems of balancing the opposing interests of upstream and
downstream states, including issues raised by human intervention, such as building dams, have been
especially acute.
Convention on the Law of the Non-Navigational Uses of International Watercourses
54
Based on a draft prepared by the ILC, the Convention was adopted by the UN General Assembly in
1997.
55
It covers non-navigational uses of, and measures of protection, preservation and
management related to, international watercourses and their waters. The Convention defines
‘watercourse’ as ‘a system of surface waters and groundwaters constituting by virtue of their
physical relationship a unitary whole [so including rivers, lakes, aquifers, glaciers, reservoirs and
canals that are interrelated with one another], and normally flowing into a common terminus’, and
‘international watercourse’ as ‘a watercourse, parts of which are situated in different states’. Since
the problems are specific to each watercourse, the Convention does not affect existing treaties.
56
The parties can conclude treaties which apply or adjust the provisions of the Convention to the
characteristics and uses of a particular watercourse, provided it does not adversely affect to a
significant extent the use by another party without its express consent (Article 3). An international
watercourse must be used in an equitable and reasonable manner. The aim is to attain optimal and
sustainable utilisation, taking into account the interests of the watercourse states concerned,
consistent with adequate protection of the watercourse (Article 5). The Convention is therefore a
framework of general and residual principles within which the parties can work to produce a regime
suited to a particular watercourse. The ICJ has already endorsed the basic principles of the
Convention.
57
So far, only fourteen states have ratified the Convention. Since it will enter into force only when
thirty-five states have ratified, it is not likely to do so for many years, if ever. But a state concerned
with a particular watercourse, whether or not it is a party to the Convention, may prefer
54. See S. McCaffrey, The Law of International Watercourses, Oxford, 2001.
55. ILM (1997) 719. For the text, the ILC final draft Articles and commentary, and a useful introduction,
see A. Watts, The International Law Commission 1949–1998, Oxford, 1999, vol. , pp. 1331–446.
56. As to which, see Birnie and Boyle, International Law and the Environment, 2nd edn, Oxford, 2002, pp.
323–9.
57. Case concerning the Gabcíkovo-Nagymaros Project (Hungary/Slovakia), ICJ Reports (1997), p. 7,
para. 85; ILM (1998) 162; 116 ILR 1.