29.2.1 Hypothetical scenario - Application of the UN Convention and protection of international watercourses during armed conflict

How does the Convention and other international law apply during armed conflict where an international watercourse may be potentially affected by such warfare? The example below demonstrates that both the laws of international watercourses (the 1997 UN Watercourses Convention) and the laws of armed conflict will apply to maintain the protection and prevention of significant harm to an international watercourse and to a non-belligerent (neutral) state’s use of the international watercourse during a time of armed conflict.430

State A is a non-riparian state sharing an international border with upstream riparian state B who is sharing international watercourse X with downstream riparian state C. State A conducts an armed attack against state B. This armed conflict may cause significant harm to the international watercourse X and to the non-belligerent downstream riparian State C’s use of watercourse X.

What obligations do states A and B owe to state C? The law of international watercourses will continue to apply to govern the relationship between belligerent state B and neutral state C despite the fact that state B is in conflict with state A. State B is still under an obligation under Article 7, Article 20 and Article 28 of the Convention to take all appropriate measures to prevent harm occurring to neutral state C. It is also argued that, due to the law of neutrality and the law of state responsibility, state A could also be under an obligation not to hinder state B in its ability to prevent or mitigate harm to state C.431 What obligations do states A and B owe to each other?

The law of armed conflict will apply directly to govern this particular circumstance of armed conflict. The general rules on the protection and use of international watercourses under the UN Watercourses Convention will also apply in providing for the obligations between states A and B. Although the relevant HR law contains more detailed provisions to deal specifically with this particular situation, this does not imply a need to balance HR law with the UN Convention as they do not conflict. A summary of the relevant instruments and rules which would apply to states A and B are as described in Figure 6.2. One important effect of these rules is that state A is generally prohibited from manipulating the international watercourse as a means of warfare.432 State A is also prohibited from attacking drinking water installations and supplies and irrigation works as well as works or installations containing dangerous forces, such as dams and dykes, but only ‘if such attack may cause the release of dangerous forces and consequent severe losses among the civilian population’ of State B.433 It is also argued that the 2004 Berlin Rules Chapter X, as a reflection of customary international law, would apply to support this general outcome.434

430 Scenario adapted from detailed commentary in Tanzi and Arcari, The United Nations Convention on the Law of International Watercourses: A Framework for Sharing at 70.

431 The principle of the law of neutrality relevant for this purpose is Art 1 of the 1907 Hague Convention No V on Respecting the Rights and Duties of Neutral Powers and Persons in Case of War on Land, which provides that ‘[t]he territory of neutral Powers is inviolable.’ Reprinted in A Roberts and R Guelff, Documents on the Laws of War (Oxford 2003). For extensive commentary on Article 29 see Tanzi and Arcari, The United Nations Convention on the Law of International Watercourses: A Framework for Sharing at 71.

432 Art 1 ENMOD.

433 Protocol II Arts 54 (2) and 56 (1).

434 Wouters, Vinogradov and Magsig, ‘Water Security, Hydrosolidarity and International Law: A River Runs through It …’ (2009) at 126.