The duty to take appropriate measures to prevent significant transboundary harm and private companies: insights from transboundary hydropower projects

Recognition that hydropower plays a role in fostering sustainable development and helping countries move away from fossil fuels has led to a resurgence of planned projects on transboundary rivers around the world. Whilst these projects offer clear benefits, they are not without their socio-ecological impacts. An added feature of hydropower projects is that they tend to involve a wide range of actors that are responsible for their financing, planning, construction and operation (international and domestic; private and State). This begs the question, if it is ultimately the responsibility of States to ensure that these projects are in accordance with international law obligations, what does that responsibility entail when much of the activity is conducted by private companies? International law has a long tradition of placing States under an obligation to regulate the conduct of non-State activities so as to prevent transboundary harm. However, a closer review of the law relating to transboundary hydropower projects reveals that more could be done to guide States as to the appropriate measures that they might put in place to ensure that any hydropower projects involving private actors are implemented in an equitable and sustainable manner.