This scenario is adapted from the 1994 ILC Draft Articles on the Law of International Watercourses and Commentaries thereto, paragraph 96.
|States A and B, whose common border is the River X, agree that each may divert 50 per cent of the river flow for domestic consumption, manufacturing and irrigation purposes at a point 25 miles upstream from state C, through which River X flows upon leaving states A and B. The total amount of water available to state C from the river, including return flow in states A and B, will be reduced as a result of the diversion, by 25 percent from what would have been available without diversion. Downstream state C relies extensively on aquaculture (especially salmon farming) on the section of the River X which flows through its territory and is concerned that the reduced flow will have an impact upon salmon migration upstream to breeding grounds.
Does state C have the right to join in consultations and negotiations, as a prospective party to any agreement, with regard to the proposed action by states A and B?
The answer is yes, state C has the right to join consultation and negotiation, but the right is qualified to the extent that it must appear that the proposed water use by State A and B will have a significant effect on state C. What constitutes ‘a significant effect’ is something greater than an ‘adverse effect’. State C must be likely to suffer from a real impairment of use, with a detrimental impact of the proposed diversion by states A and B, upon the environment or the socioeconomic development of the harmed state (e.g. public health, industry, property, and agriculture). If state C can prove objectively that the diversion will create a real impairment of use to its salmon industry, then it will be entitled to participate in consultations and negotiations relating to the agreement, and potentially to become a party thereto. If state C is not significantly affected by the proposed agreement between states A and B, regarding diversion of part of the River X, the physical unity of the river does not of itself require that state C have these rights. In these circumstances states A and B are legally entitled to enter into such an agreement without state C.
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