World Scientific Handbook of Transboundary Water Management

The following sections are included:

• Preface
• About the Editors
• About the Contributors
• Contents

International water law (IWL) comprises the legal regime that governs the relations of nations over their freshwater resources. It provides a framework for the conduct of states in relation to the regulation, allocation, management, and protection of transboundary freshwater bodies, including rivers, lakes, wetlands, and aquifers. It also provides a set of legal tools that nations can utilize when seeking cooperation and addressing disputes over internationally shared freshwater resources (Wouters, 2005). From the substantive norms of equitable and reasonable utilization and of no significant harm to the procedural principles of prior notification and exchange of information, these tools have evolved and been applied in various contexts to address growing water challenges around the world. Among others, these include rising demand, dwindling supplies, inequitable distribution, and environmental changes due to climatic and other phenomena, as well as the need to meet emerging ecological, cultural, and other priorities…

The development of international water law can be traced back to early civilizations that settled around the banks of rivers and lakes around the world. As they expanded their efforts to domesticate crops, build fluvial trade routes, and provide clean water to their populations, these communities developed complex rules for the navigation, allocation, and use of waters that cross political frontiers. This, in turn, sparked the development of what we now call international water law. Over time, as these fluvial civilizations grew and evolved, so did the law. It was adapted and modified in relation to changes in societal values, technological and political developments, and even environmental pressures. And in the past few hundred years, it was adapted to fit the new international legal order in which nation-states functioned as the main subjects of international law, and sovereignty became their mainstay.

This chapter provides a historical overview of the development and evolution of international water law. It briefly reviews the early navigation-focusing eras and then concentrates on the more modern permutations of the law and its emphasis on non-navigational uses, such as for irrigation, energy production, manufacturing, drinking water, and the environment. It also considers how the law has expanded and adapted in response to new priorities and discoveries, such as wetlands and unconventional freshwater sources, as well as how the regime interacts with other international legal regimes, including international environmental law, human rights, and the sustainable development goals.

While international water law plays a key role in managing transboundary water resources and ensuring that conflicts that could arise from the use of these resources by different actors are prevented or mitigated and that cooperation with all its benefits is being institutionalized, it is facing severe challenges. International water law has therefore received criticism — from academics and practitioners alike — that regards international water law as toothless, inefficient, or unable to deal with newly emerging challenges. This chapter critically investigates the role that international water law has played and currently plays in preventing or mitigating disagreements over shared water resources and whether and how it will be able to continue to do so under a changing climate and in light of the various other challenges emerging. It concludes that in spite of persistent shortcomings that often lie beyond the legal regime itself, international water law provides an important framework that guides states’ behavior when sharing water resources and thus prevents or mitigates disputes.

Cooperation is a fundamental principle for regulating shared watercourses. All substantive and procedural principles of international water law enjoy support of principle of cooperation for both expression and application. Since riparians must agree to cooperate and cannot cooperate in a vacuum, instruments like water treaties and agreements have become the principal medium for expression of this obligation. Current water regimes reflect cooperation by stressing institutional cooperation or by obligating riparians to cooperate. Africa in particular has progressed tremendously in managing its shared water resources through consistent emphases on the principle of cooperation though based on regional-specific approaches. Early colonial water treaties of the continent were founded largely on the desire of European colonists to cooperate over the use of shared watercourses for navigation and irrigation. Later, other early post-independent water regimes added other non-navigational uses. Current water treaties in Africa are influenced by principle of cooperation enunciated in global water treaties like the UN Watercourses Convention and UNECE Water Convention and have also evolved peculiar patterns of cooperation for managing transboundary watercourses in the regions. Principles like common works and public participation have become major drivers of cooperation particularly among riparians in West Africa, while regional instruments in South and Central Africa primarily reflect provisions of the global water treaties. In contrast, the Nile Basin states of East and North Africa, which lack a basin-wide treaty, launched the “Nile Basin Initiative” to achieve degree of cooperation that had previously eluded the region. Despite challenges of regional conflicts, paucity of funds, and climate change-related problems that confront shared watercourse management in Africa, basin states in the different regions of the continent have evolved strategies to address these challenges and achieve resilience and sustainability in both using and managing transboundary watercourses. Nevertheless, Africa and its nations could still benefit from a more coherent and progressive pattern of transboundary watercourse cooperation in order to meet the requirements of SDG Goal 6.

There are over 300 transboundary surface water basins worldwide and more than 450 known transboundary aquifer systems. Each of these has the potential for conflict if not managed properly. International water agreements can promote regional peace and security and encourage economic growth; however, states must account for their current and future uses within the natural ecosystem to ensure the best use of the water. Water divisions are often numerical and motivated by politics. With few advocates for specific water allocations for flora and fauna, nature can be entirely omitted from international water agreements and, if included, is often not addressed directly. Neglecting to include environmental considerations is harmful to the environment and can threaten the sustainability of participating states. Economic success and social sustainability are intricately tied to natural systems. Failure to consider ecosystem and watershed dynamics can undermine a shared use agreement and the communities it is meant to assist. This chapter advocates for the inclusion of environmental flow provisions in international water treaties and agreements. Inclusion of explicit environmental flow provisions better represents the economic and human health-related aspects related to existing ecosystems. To support this premise, this chapter reviews the history of international water law and existing international agreements to demonstrate that the environment has taken a backseat to water delivery obligations. This chapter also presents the science of environmental flows and the benefits ecosystem services can provide for the participating states. International water law, international law, and domestic laws are cited to provide precedent and guidance for how water should be expressly set aside for nature. Finally, this chapter proposes some specific parameters that should be included in international water negotiations to better capture environmental factors.

Historically, challenges to international water security have primarily been associated with transboundary surface waters. While water wars are rare, examples from practice and research show that there is a link between transboundary freshwater resources and international security, where disputes and conflicts related to the use, allocation, or protection of transboundary waters have seriously challenged water security. However, there are also examples of cooperation, namely over shared surface waters. While groundwater, especially in a transboundary context, has yet to be fully exploited around the world, the volume of water available to mankind from underground sources substantially exceeds the amount of water found in all of the freshwater lakes, rivers, and other surface water bodies. As the pressure on this vital source of freshwater increases, transboundary aquifers will also become the focus of water security challenges as they relate to their use, management, and conservation. The central hypothesis of this chapter is that development of international law applicable to transboundary groundwater resources can help improve global water security and prevent future conflicts. This chapter first describes the concept of water security and analyzes the link between freshwater resources and international security. It also provides examples of both water-related disputes and conflicts and successful cooperative mechanisms. The history of successful international agreements, though mostly related to surface waters, indicates that a preventative effect can be achieved especially if states conclude context-specific accords. Thus, the chapter argues that international water law can address challenges to water security and contribute to the mitigation of disputes and conflicts related to transboundary freshwater resources. More specifically, it maintains that this conclusion is similarly applicable to transboundary groundwater resources. Since international agreements addressing transboundary groundwater are generally rare, states should more intensively seek to conclude context-specific agreements on the management and allocation of shared groundwater to prevent future or mitigate already existing disputes and challenges to water security. In addition, international customary law applicable to transboundary groundwater needs to be explored in order to identify principles and trends in the law that can be used by nations for such agreements. International customary law can also fill legal gaps where states are reluctant to conclude international agreements.

International Water Law (IWL) provides a framework for cooperation on transboundary watercourses, but it may fall short of providing solutions to certain complex issues involving competing uses of water. In this context, the water–energy–food nexus approach has been developed to overcome the “siloed thinking” that has traditionally characterized water, energy, and food sectors to avoid trade-offs and promote synergies. This work explores how the nexus approach can be of support to the application of IWL’s core principles of “equitable and reasonable use,” “no harm,” and the “duty to cooperate.” To illustrate the argument, the chapter presents the case of the Aral Sea basin and analyses how its highly integrated regional hydrologic system lacks the necessary level of cooperation. The conclusion drawn is that the nexus approach incentivizes cooperation on transboundary water resources while providing grounds for the interpretation and application of the substantive principles of IWL.

This chapter aims to analyze the application of international water law, especially the principle of equitable and reasonable utilization, in light of the rights of Indigenous Peoples developed by the Inter-American Court of Human Rights (IACtHR). In this regard, the research presents the framework of the principle of equitable and reasonable utilization and the criteria for water allocation, as well as the concept of vital human needs, as established by the Convention on the Law of the Non-Navigational Uses of International Watercourses. Second, the paper presents the consolidated jurisprudence of the IACtHR on the right to water of Indigenous Peoples. Lastly, these normative elements are interpreted in a systemic approach to address the possibilities of convergence of the principle of equitable and reasonable utilization and the rights of Indigenous Peoples. The paper concludes that the principle of equitable and reasonable utilization should be interpreted in consonance with the states’ human rights obligations toward Indigenous Peoples, while the states must comply with special measures in their due diligence processes when there is a risk of affecting the groups concerned.

On June 6, 2016, the Republic of Chile initiated proceedings against the Plurinational State of Bolivia before the International Court of Justice (ICJ), to settle a dispute concerning the status and use of the waters of the Silala. On December 1, 2022, the Court delivered its judgment on the merits. Since use was made of a classic inter-state dispute settlement mechanism, the rights, and interests of local actors have been overshadowed. To ensure a meaningful role of the local actors in negotiations on future uses of the Silala, the present chapter analyzes the participatory rights of local actors in the governance of the Silala in the politically tense situation between the two states, which has led to politicization of the dispute.

Compared with international law applicable to surface water, international groundwater law has seen slower development. This has resulted in groundwater playing a secondary role in international water conventions and the adoption of fewer groundwater basin agreements. This chapter examines three main factors affecting cooperation over transboundary groundwater from a legal perspective. These factors are (1) the hidden nature of this resource, (2) lack of scientific understanding in the past and present, and (3) the potential impact of current scientific developments on the adoption of water agreements. These factors will be examined in the context of a case study, the Nubian Sandstone Aquifer System, shared among Libya, Egypt, Chad, and Sudan. Based on the analysis, recommendations are made on how these factors can strengthen the adoption and implementation of a new aquifer agreement.

Although the availability of water in South Asia is high, due to myriad problems of governance, access remains a major challenge. The size as well as the economic strength of riparians influence their treaty-making and implementing practice, compelling them to focus more on “unequal partnerships” syndromes while observing the applicable international norms and principles. Given their hydro-interdependency, the riparians deal with their problems by strategically taking an integrated or a fragmented approach, and adapting, in their unique way, to the principles of “no harm,” “equitable and reasonable use,” “notification,” and “data sharing” for water governance.

With assistance from UNESCO and the Swiss Government, cooperation among the countries sharing, respectively, the Stampriet Transboundary Aquifer System (Botswana, Namibia, and South Africa) and the Ocotepeque-Citalá Transboundary Aquifer (El Salvador and Honduras), unfolded in a familiar pattern seen elsewhere. Cooperation among the concerned countries has progressed from trust and confidence-building in the course of data collection and exchange, which generated a reliable knowledge base of the aquifers, to articulating a science-inspired multi-country response in pursuit of cooperation among the countries concerned, beyond the life of the assistance provided by external organizations. The implications of these two case examples on the evolution of international groundwater law crystallized in the UN Draft Articles on the Law of Transboundary Aquifers are illustrated and analyzed, by reference more specifically to norms related to cooperation and to joint institutions, and to the contribution of “soft law” instruments in the pursuit of cooperation. Conversely, the role of international groundwater law crystallized in the UN Draft Articles on the Law of Transboundary Aquifers, as a driver and a source of guidance for the past and continuing development of these two case scenarios is also illustrated and analyzed, by reference to the process and modalities of cooperation in regard to scientific knowledge and aquifer characterization, and to the kinds of instruments that capped that process eventually. The relevance of the two cooperation examples to the achievement of Sustainable Development Goal No. 6 is also considered.

The following section is included:

• Index