Regulation of transboundary impacts arising from the development of hydropower resources on international rivers

Situated against the backdrop of intensifying climate change and the ongoing “greening” of international water law, this paper examines the current patterns of hydropower development on international rivers and the resulting transboundary ecological and socio-economic impacts. Drawing on doctrinal analysis and selected cases, it analyzes the legal and environmental challenges associated with such projects, with particular emphasis on the principles of equitable and reasonable utilization and the obligation not to cause significant harm. These principles are assessed as core normative frameworks for both impact prevention and the allocation of responsibility. Their implementation is constrained by power asymmetries, fragmented assessment arrangements, and evidentiary barriers. The paper argues that states should subject activities posing a risk of significant transboundary harm to prior assessment procedures and undertake timely notification and consultation with potentially affected states. Achieving an equitable balance between upstream development interests and downstream protection requires a contextual evaluation of environmental risks, the significance of the proposed activity, and available mitigation measures. The analysis also distinguishes responsibility for breaches of international obligations from the conditions governing compensation for resulting environmental damage. To manage and resolve transboundary disputes, the paper highlights the complementary roles of negotiation, consultation, institutionalized international cooperation, regional governance mechanisms, and, where necessary, judicial settlement.