A legal analysis of the interinstitutional duty to cooperate in international water law

Interinstitutional interactions occur frequently and have led to important organisational developments. The purpose of this article is twofold. First, it attempts to clarify the legal basis of the interinstitutional duty to cooperate in international water law, by focusing on the river basin organisations (RBOs) of Europe and Southern Africa that coexist in the same transboundary basin. Second, it assesses the approaches used by RBOs in these two regions to operationalise the interinstitutional duty to cooperate. The article concludes that the interinstitutional duty to cooperate is far from complete and that subsequent practices of RBOs play a significant role in enriching and operationalising this duty.