29.1.1 The Convention and international law applicable in armed conflict
While international watercourses have never been the sole reason of an international armed confrontation, international watercourses and related facilities continue to be used in many instances as a military target, tool, or object.417 Article 29 of the Convention does not lay down any new rule; it simply addresses the relationship between the law of international watercourses and the rules of international law applicable during international and internal armed conflict which involves an international watercourse and its installations.418 The legal effect of Article 29 is that states will be obligated to protect and use international watercourses in accordance with the rules and principles of the Convention during times of armed conflict. However, where armed conflict affects an international watercourse including its facilities – the rules and principles of international law governing international and non-international armed conflict will also apply (see Figure 6.2).419 There are numerous prominent examples of where the destruction of a regional water supply as a result of armed conflict has resulted in widespread suffering for the local population and therefore it is important to clarify the protection afforded by this body of international law.420
It is noteworthy that unlike other provisions of the UN Watercourses Convention, Article 29 is addressed to all states, not just watercourse states, while a state not party to the Convention would not be bound by this provision, non-watercourse states are included within Article 29 because of the importance of the subject.
A further proviso to this point is that the principles and rules of armed conflicts that are ‘applicable’ in a particular case are those that are binding on the states concerned. Article 29 does not extend the applicability of any international instrument to states not parties to that instrument. Of course even with these exceptions - in cases not covered by specific international agreements, civilians and combatants will still remain under the protection and authority of the principles of customary and conventional international law governing armed conflict.421