Water scarcity, accelerated by climate change, affects water availability and may threaten peace and security. This role of water, as a contributing factor for triggering wars, sheds light on the significance of the protection of water during armed conflict. Keeping water out of war not only contributes to preserving an indispensable natural resource for life but also serves as a tool for the hostile parties to start negotiations, building trust and peace.

The no-harm principle is at the heart of the several international conventions focusing on the uses, allocation, management and protection of transboundary water resources. However, in the framework of these agreements, the meaning of “no-harm” remains rather vague. Through an analysis of six emblematic cases brought before the International Court of Justice and arbitration tribunals, we elucidate the various facets of this principle. In doing so, the paper identifies four facets. The first is characterized by concerns related to the protection of territorial integrity rather than those related to the protection of the environment. The second facet focuses on the principle of equitable and reasonable use of water, which testifies to the willingness to anticipate possible harms and to define conditions for cooperation between neighbouring countries. The third facet explores the use of three instruments and emphasizes their importance to clarify the very nature of harm: the conduct of environmental impact assessment, the consultation of local populations and the insurance of minimum environmental flows. The fourth facet develops a preventive perspective on harm by unravelling the duty to take appropriate measures to prevent and mitigate risks deriving from the obligations of notification and consultation.

Riparian states of the Senegal and Niger watersheds have developed specific techniques for the management of water infrastructure. A common feature in both watersheds is the sharing of benefits from water facilities. Niger River basin states are still at the beginning of a shared vision process for jointly managed infrastructure and equitable benefit sharing, while Senegal River basin states have led the way in innovative forms of shared ownership and governance. Environmental protection and public participation are increasingly included in the development of joint infrastructure, but more could be done to strengthen these aspects of river governance.

On 26 July 2010, the United Nations General Assembly formally recognized a human right to water and sanitation. The damages that an armed conflict causes to water infrastructure and sanitation services stand as great obstacles to the realization of this right. Taking a rights-based approach in post-conflict settings can benefit the water sector by providing international standards to which political and economic decisions may refer in the creation of water policies and decisions. International criminal tribunals and human rights courts also provide potential avenues to redress violations of the right to water and sanitation during an armed conflict.

Water is the lifeblood of human beings and society, but threats to water, such as the pollution of rivers, cyber crimes, and attacks against water infrastructure, are increasing. In green criminology, scholars have relied on domestic criminal law to develop the concept of crimes against water. This paper argues that international law could provide several frameworks for addressing these crimes. A number of international treaties and customary rules deal directly or indirectly with crimes against water, and the United Nations Security Council has also dealt with crimes against water committed by terrorist groups and parties to armed conflict. Crimes against water may represent violations not only of domestic criminal laws but also of international humanitarian law and human rights law.

Quasi-judicial bodies have flourished in various areas of international law in the last few decades. These bodies have a mandate to monitor compliance with a body of norms, settle disputes involving those norms, or make factual determinations on the basis of investigations, yet they are not empowered to issue final, binding decisions on questions of international law. This chapter argues that quasi-judicial bodies can be viewed as international lawmakers. They act as procedural rule-makers and are developing a shared collection of principles structuring their procedures. The chapter further suggests that quasi-judicial bodies also act as lawmakers on substantive issues by influencing the interpretation, clarification and refinement of State duties and responsibilities. Quasi-judicial bodies have proved influential in the interpretation of State responsibilities by both national and international courts. Like judicial bodies, they foster compliance with international law and resolve potential conflicts.