Water marketing and property right reform are intertwined. Water markets are advocated as a solution for water scarcity, but changes in water rights are often required if the scope of water marketing is to expand. This is true in many countries, including (but not limited to) the United States and Australia. The focus here is on the United States. So far, water marketing in the Western United States is not producing long-run reallocation on the scale expected. The chief impediment is the complexities in existing water rights. An important distinction is between a property right to extract water and put it to use versus a contractual right to receive water from a supply organization. In the United States, the property right to water is a unique form of property. Unlike land, it is a right of use, not ownership; the quantity afforded by the right is incompletely specified; and the ability to transfer it is constrained by the obligation to avoid harm through the externality of return flows and also by unreliable historical records of rights. These constraints are often relaxed for short-term transfers (leases) of a property right lasting only a year or two. Also, these constraints generally do not apply to a contract right to receive water. Thus, most of the surface water transferred in the United States is either contract water moving within supply system boundaries or short-term leases of appropriative rights. These transfers tend to provide short-run flexibility for water users rather than long-run reallocation. For more significant long-run reallocation of water, some modification of the property right to water is essential. Devising a politically acceptable way to make the needed changes is the ultimate constraint on water marketing.
The Problem of Water Markets
Rethinking Water Markets
Rupert Quentin Grafton, James Horne, and Sarah A. Wheeler
Global water extractions from streams, rivers, lakes, and aquifers are continuously increasing, yet some four billion people already face severe water scarcity for at least one month per year. Deteriorating water security will, in the absence in how water is governed, get worse with climate change, as modeling projections indicate that much of the world’s arid and semiarid locations will receive less rainfall into the future. Concomitant with climate change is a growing world population, expected to be about 10 billion by 2050, that will greatly increase the global food demand, but this demand cannot be met without increased food production that depends on an adequate supply of water for agriculture. This poses a global challenge: How to ensure immediate and priority needs (such as safe drinking water) are satisfied without compromising future water security and the long-term sustainability of freshwater ecosystems? An effective and sustainable response must resolve the “who gets what water and when” water allocation problem and promote water justice. Many decision makers, however, act as if gross inequities in water access can be managed by “business as usual” and upgrades in water infrastructure alone. But much more is needed if the world is to achieve its Sustainable Development Goal of “water and sanitation for all” by 2030. Transformational change is required such that the price paid for water by users includes the economic costs of supply and use and the multiple values of water. Water markets in relation to physical volumes of water offer one approach, among others, that can potentially deliver transformational change by: (a) providing economic incentives to promote water conservation and (b) allowing water to be voluntarily transferred among competing users and uses (including non-uses for the environment and uses that support cultural values) to increase the total economic value from water. Realizing the full potential of water markets, however, is a challenge, and formal water markets require adequate regulatory oversight. Such oversight, at a minimum, must ensure: (a) the metering, monitoring, and compliance of water users and catchment-scale water auditing; (b) active compliance to protect both buyers and sellers from market manipulations; and (c) a judiciary system that supports the regulatory rules and punishes noncompliance. In many countries, the institutional and water governance framework is not yet sufficiently developed for water markets. In some countries, such as Australia, China, Spain, and the United States, the conditions do exist for successful water markets, but ongoing improvements are still needed as circumstances change in relation to water users and uses, institutions, and the environment. Importantly, into the future, water markets must be designed and redesigned to promote both water security and water justice. Without a paradigm shift in how water is governed, and that includes rethinking water markets to support efficiency and equitable access, billions of people will face increasing risks to their livelihoods and lives and many fresh-water environments will face the risk of catastrophic decline.
Politics of Local Community Engagement in Transboundary Water Negotiations
Isabela Espindola and Pilar Villar
The sharing of transboundary water resources, whether surface or groundwater, is a significant challenge, both in theory and practice. Countries in situations of sharing these natural resources are predisposed to interact with each other. These interactions, here called transboundary water interactions, are characterized by the coexistence of cooperation and conflict, which can arise at different governance levels. However, negotiations around transboundary water resources primarily occur between diplomats and high government members from riparian countries and river basin organization (RBO) managers. Transboundary water negotiations are usually considered high-level political discussions, given the complexity and scale of the water challenges. Consequently, decision-making processes incorporate only a limited number of participants, who make decisions capable of impacting the entire population that depend on the shared waters. Over the last 20 years, there has been a need for greater transparency and a participatory process in transboundary water negotiations, especially for local community engagement and collaboration in these processes. Many of the negotiation processes around transboundary water resources need the participation of municipalities and local populations, concomitant with the involvement of RBOs, to carry out decisions to manage transboundary waters in an integrated manner. There are several reasons for this demand, including negotiation effectiveness, contestation prevention, data sharing, ensuring continuing participation and collaboration, and promoting public awareness related to water resources. Discussing social participation, particularly in the management of transboundary water resources, requires attention to the historical context and its constraints. Considering the enormous challenge, the experiences of local community engagement in transboundary water negotiations in South America, especially from the Guarani Aquifer and the La Plata Basin, are good examples for improving this discussion around transboundary water interactions and local community engagement. The La Plata Basin is the second-largest transboundary basin in the continent, shared by Argentina, Bolivia, Brazil, Uruguay, and Paraguay, while the Guarani Aquifer is one of the largest reservoirs of freshwater worldwide, shared by Argentina, Brazil, Paraguay, and Uruguay. Even with both having cooperation agreements in place between the riparian states, there are still great difficulties with regard to the participation of local communities in transboundary water negotiations.
Claudia Sadoff, David Grey, and Edoardo Borgomeo
Water security has emerged in the 21st century as a powerful construct to frame the water objectives and goals of human society and to support and guide local to global water policy and management. Water security can be described as the fundamental societal goal of water policy and management. This article reviews the concept of water security, explaining the differences between water security and other approaches used to conceptualize the water-related challenges facing society and ecosystems and describing some of the actions needed to achieve water security. Achieving water security requires addressing two fundamental challenges at all scales: enhancing water’s productive contributions to human and ecosystems’ well-being, livelihoods and development, and minimizing water’s destructive impacts on societies, economies, and ecosystems resulting, for example, from too much (flood), too little (drought) or poor quality (polluted) water.
Manuel Pulido-Velazquez and Amaury Tilmant
The management of water resources systems involves influencing and improving the interaction among three subsystems: natural (biophysical), economic, and legal-institutional frameworks. In this sense, hydroeconomic models have the advantage of analyzing water management problems through models that explicitly represent these interactions. The combination of economic, engineering, and environmental aspects of management provides better-informed results for decision making in the complex environment in which water management operates. Hydroeconomic models (HEMs) are spatially distributed management models of a river basin or system in which both water supply and demands are economically and hydrologically characterized. This definition is sometimes relaxed to refer in general to water resources management models that include the economic component. In HEMs, the management and allocation of water is either driven by the economic value of water or economically assessed, which contributes to policy analysis and reveals opportunities for better economic management. The traditional view of water demand as a fixed requirement to be satisfied is modified by a view of demand that adapts to the changes in the scarcity of water. The integration of economics in HEMs allows the identification of the best combination of water supply and demand management options within a consistent framework. As water scarcity increases worldwide, water managers will increasingly turn to tools that reveal solutions to increase efficiency in water use, fostering improved economic development through better-informed policy choices.
Smart Cities and Water Infrastructure
Water infrastructure is the system of physical (both built and environmental), social (e.g., governance), and technological elements that move water into, throughout, and out of human communities. It includes, but is not limited to, water supply infrastructure (e.g., pipe systems, water treatment facilities), drainage and flood infrastructure (e.g., storm sewers, green infrastructure systems, levees), and wastewater treatment infrastructure (e.g., pipe systems, wastewater treatment plants, reclaimed water facilities). Smart city approaches to water infrastructure emphasize integration of information and communication technologies with urban water infrastructure and services, usually with the goal of increasing efficiency and human well-being. Smart water meters, smart water grids, and other water-related information and communication technologies have the potential to improve overall infrastructure efficiency, to reduce water use, to match new water supplies with appropriate water uses, to innovate wastewater treatment, and to protect residents from floods and other water-related climate events. However, without stronger attention to issues of equity, social systems, governance, ecology, and place, a smart city approach to water infrastructure may achieve efficiencies but fail to generate broader socioecological values or to contribute toward climate adaptation.
Decision-Making in a Water Crisis: Lessons From the Cape Town Drought for Urban Water Policy
Johanna Brühl, Leonard le Roux, Martine Visser, and Gunnar Köhlin
The water crisis that gripped Cape Town over the 2016–2018 period gained global attention. For a brief period of time in early 2018, it looked as if the legislative capital of South Africa would become the first major city in the world to run out of water. The case of Cape Town has broad implications for how we think about water management in a rapidly urbanizing world. Cities in the global South, especially, where often under-capacitated urban utilities need to cope with rapid demographic changes, climate change, and numerous competing demands on their tight budgets, can learn from Cape Town’s experience. The case of Cape Town draws attention to the types of decisions policymakers and water utilities face in times of crisis. It illustrates how these decisions, while being unavoidable in the short term, are often sub-optimal in the long run. The Cape Town drought highlights the importance of infrastructure diversification, better groundwater management, and communication and information transparency to build trust with the public. It also shows what governance and institutional changes need to be made to ensure long-term water security and efficient water management. The implementation of all of these policies needs to address the increased variability of water supplies due to increasingly erratic rainfall and rapidly growing urban populations in many countries. This necessitates a long-term planning horizon.
Global Climate Change and the Reallocation of Water
Rhett B. Larson
Increased water variability is one of the most pressing challenges presented by global climate change. A warmer atmosphere will hold more water and will result in more frequent and more intense El Niño events. Domestic and international water rights regimes must adapt to the more extreme drought and flood cycles resulting from these phenomena. Laws that allocate rights to water, both at the domestic level between water users and at the international level between nations sharing transboundary water sources, are frequently rigid governance systems ill-suited to adapt to a changing climate. Often, water laws allocate a fixed quantity of water for a certain type of use. At the domestic level, such rights may be considered legally protected private property rights or guaranteed human rights. At the international level, such water allocation regimes may also be dictated by human rights, as well as concerns for national sovereignty. These legal considerations may ossify water governance and inhibit water managers’ abilities to alter water allocations in response to changing water supplies. To respond to water variability arising from climate change, such laws must be reformed or reinterpreted to enhance their adaptive capacity. Such adaptation should consider both intra-generational equity and inter-generational equity. One potential approach to reinterpreting such water rights regimes is a stronger emphasis on the public trust doctrine. In many nations, water is a public trust resource, owned by the state and held in trust for the benefit of all citizens. Rights to water under this doctrine are merely usufructuary—a right to make a limited use of a specified quantity of water subject to governmental approval. The recognition and enforcement of the fiduciary obligation of water governance institutions to equitably manage the resource, and characterization of water rights as usufructuary, could introduce needed adaptive capacity into domestic water allocation laws. The public trust doctrine has been influential even at the international level, and that influence could be enhanced by recognizing a comparable fiduciary obligation for inter-jurisdictional institutions governing international transboundary waters. Legal reforms to facilitate water markets may also introduce greater adaptive capacity into otherwise rigid water allocation regimes. Water markets are frequently inefficient for several reasons, including lack of clarity in water rights, externalities inherent in a resource that ignores political boundaries, high transaction costs arising from differing economic and cultural valuations of water, and limited competition when water utilities are frequently natural monopolies. Legal reforms that clarify property rights in water, specify the minimum quantity, quality, and affordability of water to meet basic human needs and environmental flows, and mandate participatory and transparent water pricing and contracting could allow greater flexibility in water allocations through more efficient and equitable water markets.
Integrated Water Resource Management as an Organizing Concept
Mohamed Ait-Kadi and Melvyn Kay
This is an immersive journey through different water management concepts. The conceptual attractiveness of concepts is not enough; they must be applicable in the real and fast-changing world. Thus, beyond the concepts, our long-standing challenge remains increasing water security. This is about stewardship of water resources for the greatest good of societies and the environment. It is a public responsibility requiring dynamic, adaptable, participatory, and balanced planning. It is all about coordination and sharing. Multi-sectoral approaches are needed to adequately address the threats and opportunities relating to water resources management in the context of climate change, rapid urbanization, and growing disparities. The processes involved are many and need consistency and long-term commitment to succeed. Climate change is closely related to the problems of water security, food security, energy security and environment sustainability. These interconnections are often ignored when policy-makers devise partial responses to individual problems. They call for broader public policy planning tools with the capacity to encourage legitimate public/collective clarification of the trade-offs and the assessment of the potential of multiple uses of water to facilitate development and growth. We need to avoid mental silos and to overcome the current piecemeal approach to solving the water problems. This requires a major shift in practice for organizations (governmental as well as donor organizations) accustomed to segregating water problems by subsectors. Our experience with integration tells us that (1) we need to invest in understanding the political economy of different sectors; (2) we need new institutional arrangements that function within increasing complexity, cutting across sectoral silos and sovereign boundaries; (3) top down approaches for resources management will not succeed without bottom-up efforts to help people improve their livelihoods and their capacity to adapt to increasing resource scarcity as well as to reduce unsustainable modes of production. Political will, as well as political skill, need visionary and strong leadership to bring opposing interests into balance to inform policy- making with scientific understanding, and to negotiate decisions that are socially accepted. Managing water effectively across a vast set of concerns requires equally vast coordination. Strong partnerships and knowledge creation and sharing are essential. Human civilization – we know- is a response to challenge. Certainly, water scarcity can be a source of conflict among competing users, particularly when combined with other factors of political or cultural tension. But it can also be an inducement to cooperation even in high tension areas. We believe that human civilization can find itself the resources to respond successfully to the many water challenges, and in the process make water a learning ground for building the expanded sense of community and sharing necessary to an increasingly interconnected world.
Desalination Technology and Advancement
P.S. Goh, A.F. Ismail, and N. Hilal
Water scarcity as an outcome of global population expansion, climate change, and industrialization calls for new and innovative technologies to provide sustainable solutions to address this alarming issue. Seawater and brackish water are abundantly available on earth for drinking water and industrial use, and desalination is a promising approach to resolving this global challenge. Recently, the considerable reduction in the cost of desalination has contributed to the growing capacity for global desalination. The desalination technologies that have been deployed worldwide for clean water production can be categorized into two main types: membrane-based and thermal-based. Technological advancement in this field has focused on the reduction of capital and operating cost, particularly the energy consumption of the systems. Seawater and brackish desalination technologies are promising solutions for water shortages.
Agricultural Nitrogen and Phosphorus Pollution in Surface Waters
Marianne Bechmann and Per Stålnacke
Nutrient pollution can have a negative impact on the aquatic environment, with loss of biodiversity, toxic algal blooms, and a deficiency in dissolved oxygen in surface waters. Agricultural production is one of the main contributors to these problems; this article provides an overview of and background for the main biogeochemical processes causing agricultural nutrient pollution of surface waters. It discusses the main features of the agricultural impact on nutrient loads to surface waters, focusing on nitrogen and phosphorus, and describes some of the main characteristics of agricultural management, including processes and pathways from soil to surface waters. An overview of mitigation measures to reduce pollution, retention in the landscape, and challenges regarding quantification of nutrient losses are also dealt with. Examples are presented from different spatial scales, from field and catchment to river basin scale.
Water Federalism in the United States of America
Rebecca F.A. Bernat and Sharon B. Megdal
Water governance in the United States has followed a water federalism system, in which government functions are shared between federal and state authorities. Water federalism is the sharing of governance across different levels of government over freshwater quantity (water quantity federalism) and quality (water quality federalism). These terms have evolved throughout different eras of U.S. history. Initially, water federalism involved water quantity federalism only, and both state and federal governments had management prerogatives. The 1922 Colorado River Compact and the 1944 U.S. and Mexico Treaty are examples of a combination of horizontal and vertical federalisms. Then, the 1970s marked significant changes in water federalism. First, states regained control over water resources management. Second, water quality federalism arose as a subset of, and at the same time as, environmental federalism. The 1972 Clean Water Act is an example of cooperative federalism, which was commonly used to refer to environmental federalism. In the 21st century, a variety of environmental federalism frameworks have been offered to address the negative effects of climate change on water resources as well as other environmental issues. The contemporary literature on environmental federalism encompasses water quantity and water quality federalism. Throughout history, the role of American Indian tribal primacy has been overlooked in the water federalism literature. Another layer of government, the American Indian tribal government, should be included in discussing states versus federal water management prerogatives. Overall, new water quality and water quantity federalisms must be developed using institutional, sociocultural, and economic principles of good governance that foster a more inclusive, participatory, democratic, and engaged form of federalism.
Smart One Water: An Integrated Approach for the Next Generation of Sustainable and Resilient Water Systems
Sunil K. Sinha, Meghna Babbar-Sebens, David Dzombak, Paolo Gardoni, Bevlee Watford, Glenda Scales, Neil Grigg, Edgar Westerhof, Kenneth Thompson, and Melissa Meeker
Quality of life for all people and communities is directly linked to the availability of clean and abundant water. Natural and built water systems are threatened by crumbling infrastructure, floods, drought, storms, wildfires, sea-level rise, population growth, cybersecurity breaches, and pollution, often in combination. Marginalized communities feel the worst impacts, and responses are hampered by fragmented and antiquated governance and management practices. A standing grand challenge for the water sector is transitioning society to a future where current silos are transformed into a significantly more efficient, effective, and equitable One Water system-of-systems paradigm—in other words, a future where communities are able to integrate the governance and management of natural and engineered water systems at all scales of decision-making in a river basin. Innovation in digital technologies that connect data, people, and organizations can be game changers in addressing this societal grand challenge. It is envisioned that advancing digital capabilities in the water sector will require a Smart One Water approach, one that builds upon new technologies and research advancements in multiple disciplines, including those in engineering, computer science, and social science. However, several fundamental knowledge gaps at the nexus of physical, social, and cyber sciences currently exist on how a nationwide Smart One Water approach can be created, operationalized, and maintained. Convergent research is needed to investigate these gaps and improve our current understanding of Smart One Water approaches, including the costs, risks, and benefits to diverse communities in the rural-to-urban continuum. At its core, implementing the Smart One Water approach requires a science-based, stakeholder-driven, and artificial intelligence (AI)–enabled cyberinfrastructure platform, one that can provide a robust framework to support networks of river-basin collaborations. We refer to this envisioned cyberinfrastructure foundation as the digital research and operational platform (DROP). DROP is envisioned to exploit advances in data analytics, machine learning, information, communication, and decision support technologies for the management of One Water systems via AI-enabled digital twins of river-basin systems. Deploying DROP at a large-basin scale requires an understanding of (a) physical water systems (natural and engineered) at the basin scale, which interact with each other in a dynamic environment affected by climate change and other societal trends and whose data, functions, and processes must be integrated to create digital twins of river basins; (b) the social aspects of One Water systems by understanding the values and perspectives of stakeholders, costs and benefits of water management practices and decisions, and the specific needs of disadvantaged populations in river basin communities; (c) approaches for developing and deploying the digital technologies, analytics, and AI required to efficiently operate and manage Smart One Water systems in small to large communities; (d) strategies for training and advancing the next-generation workforce who have expertise on cyber, physical, and social aspects of One Water systems; and (e) lessons learned from testing and evaluating DROP in diverse testbeds. The article describes a strategic plan for operationalizing Smart One Water management and governance in the United States. The plan is based on five foundational pillars: (a) river-basin scale governance, (b) workforce development, (c) innovation ecosystem, (d) diversity and inclusion, and (e) stakeholder engagement. Workshops were conducted for each foundational pillar among diverse stakeholders representing federal, state, and local governments; utilities; industry; nongovernmental organizations; academics; and the general public. The workshops confirmed the strong desire of water communities to embrace, integrate, and grow the Smart One Water approach. Recommendations were generated for using the foundational pillars to guide strategic plans to implement a national-scale Smart One Water program and facilitate its adoption by communities in the United States, with global applications to follow.
The Street-Level Bureaucracy at the Intersection of Formal and Informal Water Provision
Street-level bureaucrats (SLBs) interact directly with users and play a key role in providing services. In the Global South, and specifically in India, the work practices of frontline public workers—technical staff, field engineers, desk officers, and social workers—reflect their understanding of urban water reforms. The introduction of technology-driven solutions and new public management instruments, such as benchmarking, e-governance, and evaluation procedures, has transformed the nature of frontline staff’s responsibilities but has not solved the structural constraints they face. In regard to implementing solutions to improve access in poor neighborhoods, SLBs continue to play a key role in the making of formal and informal provision. Their daily practices are ambivalent. They can be both predatory and benevolent, which explains the contingent impacts on service improvement and the difficulty in generalizing reform experiments. Nevertheless, the discretionary power of SLBs can be a source of flexibility and adaptation to complex social settings.
Optimal and Real-Time Control of Water Infrastructures
Ronald van Nooijen, Demetris Koutsoyiannis, and Alla Kolechkina
Humanity has been modifying the natural water cycle by building large-scale water infrastructure for millennia. For most of that time, the principles of hydraulics and control theory were only imperfectly known. Moreover, the feedback from the artificial system to the natural system was not taken into account, either because it was too small to notice or took too long to appear. In the 21st century, humanity is all too aware of the effects of our adaptation of the environment to our needs on the planetary system as a whole. It is necessary to see the environment, both natural and hman-made as one integrated system. Moreover, due to the legacy of the past, the behaviour of the man-madeparts of this system needs to be adapted in a way that leads to a sustainable ecosystem. The water cycle plays a central role in that ecosystem. It is therefore essential that the behaviour of existing and planned water infrastructure fits into the natural system and contributes to its well-being. At the same time, it must serve the purpose for which it was constructed. As there are no natural feedbacks to govern its behaviour, it will be necessary to create such feedbacks, possibly in the form of real-time control systems. To do so, it would be beneficial if all persons involved in the decision process that establishes the desired system behaviour understand the basics of control systems in general and their application to different water systems in particular. This article contains a discussion of the prerequisites for and early development of automatic control of water systems, an introduction to the basics of control theory with examples, a short description of optimal control theory in general, a discussion of model predictive control in water resource management, an overview of key aspects of automatic control in water resource management, and different types of applications. Finally, some challenges faced by practitioners are mentioned.
The Basic Systems of Surface Water Allocation
Joseph W. Dellapenna
From earliest times, at least in arid and semi-arid regions, law has been used to allocate water to particular users, at particular locations, and for particular uses, as well as to regulate the uses of water. In the early 21st century, such laws are found everywhere in the world. While the details of such systems of water law are specific to each culture, these systems, in general terms, conform to one of three basic patterns, or to some combination thereof. The three patterns can be understood as a system of common property, a system of private property, or a system of public property. In a common property system, each person is free to use water as he or she chooses so long as the person has lawful access to the water source and does not unreasonably interfere with other lawful users. Such systems were common in humid regions where generally there was enough water available for all uses, but these break down when demand begins to outstrip supply frequently. Private property systems, more common in arid and semi-arid regions, where water is generally not available to meet all demand on the water sources, is a system that allocates specific amounts of water from an identified water source, for a particular water use at a particular location, and with a definite priority relative to other uses. The problem with such private property systems is their rigidity, with transfers of existing water allocations to new uses or new locations proving difficult in practice. In Australia, the specified claim on a water source is defined not as a quantity, but as a percentage of the available flow. Despite the praise heaped upon this system, it has proven difficult to implement without heavy government intervention, benefiting only large irrigators without adequately addressing the public values that water sources must serve. In part, the problems arise because cheating is easier in the absence of clear volumetric entitlements. The public property systems, which has roots dating back centuries but is largely an artifact of the 20th century, treats water as subject to active public management, whether through collaborative decision-making by stakeholders (a situation that is also sometimes called “common property” but is actually very different from the concept of common property used here), or through governmental institutions. Public property systems seek to avoid the deficiencies of the other two systems (particularly by avoiding the incessant conflicts characteristic of common property systems as demand approaches supply and the rigidity characteristics of actual private property systems), but at the cost of introducing bureaucratized decision making. In the late 20th century, many stakeholders, governments, and international institutions turned to market systems—usually linked to a revived or new private property system—as the supposed optimum means to allocate and re-allocate water to particular uses, users, and locations. Before the late 20th century, markets were rare and small, but institutions like the World Bank set about to make them the primary mechanism for water allocation. Markets, however, proved difficult to implement, at least without transferring wealth from relatively poor users to more prosperous users, and therefore produced a backlash in the form of support for a human right to water that would trump the private property claims central to water markets. The protection of public values, such as ecological or navigational flows, also proved difficult to maintain in the face of the demands of the marketplace. Each of these systems has proven useful in particular settings, but none of them can be universally applied.
Francesca Greco, Martin Keulertz, and David Dent
Virtual water is the water contained in food, understood not only as the physical amount within the product but also as the amount of water required to generate it over time, from planting to final harvest. Despite Tony Allan defined virtual water in the context of the water needed to produce agricultural commodities, the concept has been subsequently expanded to include the water needed to produce non-agricultural commodities and industrial goods by Arjen Hoekstra, the creator of the water footprint indicator. Virtual water is a revolutionary concept because it describes something never conceptualized before: the water “embedded” in a product. Allan used virtual water “food water” and “embedded water” as interchangeable terms. Virtual water “trade” is the result of food trade: where agricultural goods are traded across countries, the water needed to produce that product in country A is, in fact, consumed in country B. Country B is therefore not consuming its own local resources when consuming imported food. Allan believed that this mechanism could alleviate irrigation water needs in water-scarce areas when food imports are in place. The virtual water content of a product (measured in liters per kilo) is provided not only by the sum of the irrigation water that has been withdrawn from surface and underground sources in order to grow crops—called “blue water.” Virtual water is also composed of the rainwater consumed by plants and persisting in agricultural soil moisture, which does not percolate down to the aquifers or go back to rivers and lakes. This second component is called “green water.” The green- and blue-water components form the total amount of water embedded in crops, and they are the two components of virtual water. Allan borrowed the concepts of green and blue water from the work of Malin Falkenmark. Virtual water and virtual water “trade” have been largely explored and studied at both local and global levels, becoming the subjects of thousands of papers between 1993 and 2022, which helped uncover global appropriation of a local resource that is unevenly distributed by nature and very often unequally “traded” by humans: water.
Economics of Water Scarcity in China
Water scarcity has long been recognized as a key issue challenging China’s water security and sustainable development. Economically, China’s water scarcity can be characterized by the uneven distribution of limited water resources across space and time in hydrological cycles that are inconsistent with the rising demand for a sufficient, stable water supply from rapid socioeconomic development coupled with a big, growing population. The limited water availability or scarcity has led to trade-offs in water use and management across sectors and space, while negatively affecting economic growth and the environment. Meanwhile, inefficiency and unsustainability prevail in China’s water use, attributable to government failure to account for the socioeconomic nature of water and its scarcity beyond hydrology. China’s water supply comes mainly from surface water and groundwater. The nontraditional sources, wastewater reclamation and reuse in particular, have been increasingly contributing to water supply but are less explored. Modern advancement in solar and nuclear power development may help improve the potential and competitiveness of seawater desalination as an alternative water source. Nonetheless, technological measures to augment water supply can only play a limited role in addressing water scarcity, highlighting the necessity and importance of nontechnological measures and “soft” approaches for managing water. Water conservation, including improving water use efficiency, particularly in the agriculture sector, represents a reasonable strategy that has much potential but requires careful policy design. China’s water management has started to pay greater attention to market-based approaches, such as tradable water rights and water pricing, accompanied by management reforms. In the past, these approaches have largely been treated as command-and-control tools for regulation rather than as economic instruments following economic design principles. While progress has been made in promoting the market-based approaches, the institutional aspect needs to be further improved to create supporting and enabling conditions. For water markets, developing regulations and institutions, combined with clearly defining water use rights, is needed to facilitate market trading of water rights. For water pricing, appropriate design based on the full cost of water supply needs to be strengthened, and policy implementation must be enforced. An integrated approach is particularly relevant and greatly needed for China’s water management. This approach emphasizes integration and holistic consideration of water in relation to other resource management, development opportunities, and other policies across scales and sectors to achieve synergy, cost-effectiveness, multiple benefits, and eventually economic efficiency. Integrated water management has been increasingly applied, as exemplified by a national policy initiative to promote urban water resilience and sustainability. While economics can play a critical role in helping evaluate and compare alternative measures or design scenarios and in identifying multiple benefits, there is a need for economic or social cost–benefit analysis of China’s water policy or management that incorporates nonmarket costs and benefits.
Water User Associations and Collective Action in Irrigation and Drainage
If there is too little or too much water, farmers may be able to work together to control water and grow more food. Even before the rise of cities and states, people living in ancient settlements cooperated to create better growing conditions for useful plants and animals by diverting, retaining, or draining water. Local collective action by farmers continued to play a major role in managing water for agriculture, including in later times and places when rulers sometimes also organized construction of dams, dikes, and canals. Comparative research on long-lasting irrigation communities and local governance of natural resources has found immense diversity in management rules tailored to the variety of local conditions. Within this diversity, Elinor Ostrom identified shared principles of institutional design: clear social and physical boundaries; fit between rules and local conditions, including proportionality in sharing costs and benefits; user participation in modifying rules; monitoring by users or those accountable to them; graduated sanctions to enforce rules; low-cost conflict resolution; government tolerance or support for self-governance; and nested organizations. During the 19th and 20th centuries, centralized bureaucracies constructed many large irrigation schemes. Farmers were typically expected to handle local operation and maintenance and comply with centralized management. Postcolonial international development finance for irrigation and drainage systems usually flowed through national bureaucracies, strengthening top-down control of infrastructure and water management. Pilot projects in the 1970s in the Philippines and Sri Lanka inspired internationally funded efforts to promote participatory irrigation management in many countries. More ambitious reforms for transfer of irrigation management to water user associations (WUAs) drew on examples in Colombia, Mexico, Turkey, and elsewhere. These reforms have shown the feasibility in some cases of changing policies and practices to involve irrigators more closely in decisions about design, construction, and some aspects of operation and maintenance, including cooperation in scheme-level co-management. However, WUAs and associated institutional reforms are clearly not panaceas and have diverse results depending on context and on contingencies of implementation. Areas of mixed or limited impact and for potential improvement include performance in delivering water; maintaining infrastructure; mobilizing local resources; sustaining organizations after project interventions; and enhancing social inclusion and equity in terms of multiple uses of water, gender, age, ethnicity, poverty, land tenure, and other social differences. Cooperation in managing water for agriculture can contribute to coping with present and future challenges, including growing more food to meet rising demand; competition for water between agriculture, industry, cities, and the environment; increasing drought, flood, and temperatures due to climate change; social and economic shifts in rural areas, including outmigration and diversification of livelihoods; and the pursuit of environmental sustainability.
Historical Development of the Global Water Cycle as a Science Framework
Richard G. Lawford and Sushel Unninayar
The global water cycle concept has its roots in the ancient understanding of nature. Indeed, the Greeks and Hebrews documented some of the most some important hydrological processes. Furthermore, Africa, Sri Lanka, and China all have archaeological evidence to show the sophisticated nature of water management that took place thousands of years ago. During the 20th century, a broader perspective was taken and the hydrological cycle was used to describe the terrestrial and freshwater component of the global water cycle. Data analysis systems and modeling protocols were developed to provide the information needed to efficiently manage water resources. These advances were helpful in defining the water in the soil and the movement of water between stores of water over land surfaces. Atmospheric inputs to these balances were also monitored, but the measurements were much more reliable over countries with dense networks of precipitation gauges and radiosonde observations. By the 1960s, early satellites began to provide images that gave a new perception of Earth processes, including a more complete realization that water cycle components and processes were continuous in space and could not be fully understood through analyses partitioned by geopolitical or topographical boundaries. In the 1970s, satellites delivered quantitative radiometric measurements that allowed for the estimation of a number of variables such as precipitation and soil moisture. In the United States, by the late 1970s, plans were made to launch the Earth System Science program, led by the National Aeronautics and Space Agency (NASA). The water component of this program integrated terrestrial and atmospheric components and provided linkages with the oceanic component so that a truly global perspective of the water cycle could be developed. At the same time, the role of regional and local hydrological processes within the integrated “global water cycle” began to be understood. Benefits of this approach were immediate. The connections between the water and energy cycles gave rise to the Global Energy and Water Cycle Experiment (GEWEX)1 as part of the World Climate Research Programme (WCRP). This integrated approach has improved our understanding of the coupled global water/energy system, leading to improved prediction models and more accurate assessments of climate variability and change. The global water cycle has also provided incentives and a framework for further improvements in the measurement of variables such as soil moisture, evapotranspiration, and precipitation. In the past two decades, groundwater has been added to the suite of water cycle variables that can be measured from space. New studies are testing innovative space-based technologies for high-resolution surface water level measurements. While many benefits have followed from the application of the global water cycle concept, its potential is still being developed. Increasingly, the global water cycle is assisting in understanding broad linkages with other global biogeochemical cycles, such as the nitrogen and carbon cycles. Applications of this concept to emerging program priorities, including the Sustainable Development Goals (SDGs) and the Water-Energy-Food (W-E-F) Nexus, are also yielding societal benefits.