Protection of prior and late developers of transboundary water resources in international treaty practices: a review of 416 international water agreements

The question of balancing the competing uses of prior and late developers has long been the core issue in international water law (IWL). Yet, how IWL evolves to assure the flexibility and continuing adaptability of its norms in the context of changing circumstances of water use regimes, has not been the subject of comprehensive academic research. Based on an empirical analysis of 459 international water treaties, this research reveals that equal protection of prior use and later use is becoming an emerging trend for international treaty practices, while obligations of “due diligence” emerge to redefine the “no-harm” principle; the growing concern for environmental protection challenges the basic understanding of the concepts of “harm” and “reasonableness”. To strengthen the trend for equal protection and to ensure greater flexibility and adaptability of IWL, this paper focuses on the promotion of institutional water cooperation, the forging of common understanding over the importance of transboundary environmental protection, and the development of more up-to-date global legal frameworks.