Water is an essential resource and is under increased strain year after year. Fresh water can be a difficult resource to come by, but the solution may lie in the invisible water source that surrounds us. The atmosphere contains 12.9 trillion m3 of fresh water in liquid and vapor forms. Rain and fog harvesting were the first solutions developed in ancient times, taking advantage of water that already existed in a liquid state. These technologies do not require energy input to overcome the enthalpy of condensation and thus are passive in nature. They are, however, limited to climates and regions that experience regular rainfall or 100% relative humidity (RH) for rainwater and fog harvesting, respectively. People living in areas outside of the usable range needed to look deeper for a solution. With the advent of refrigeration in the 20th century, techniques came that enabled access to the more elusive water vapor (i.e., <100% RH) that exists in the atmosphere. Refrigeration based dewing (RBD) is the most common technique of collecting water vapor from the atmosphere and was first developed in the 1930s but found greater adoption in the 1980s. RBD is the process of cooling ambient air to the dew point temperature. At this temperature water vapor in the atmosphere will begin to condense, forming liquid droplets. As the humidity ratio, or amount of water in a given quantity of air (gwater/kgdry-air) continues to decrease, RBD becomes infeasible. Below a threshold of about 3.5 gwater/kgdry-air the dewpoint temperature is below the freezing point and ice is formed during condensation in place of liquid water. Since the turn of the century, many researchers have made significant progress in developing a new wave of water harvesters capable of operating in much more arid climates than previously accessible with RBD. At lower humidity ratios more effort must be expended to produce the same amount of liquid water. Membrane and sorbent-based systems can be designed as passive or active; both aim to gather a high concentration of water vapor from the ambient, creating local regions of increased relative humidity. Sorbent-based systems utilize the intrinsic hydrophilicity of solid and liquid desiccants to capture and store water vapor from the atmosphere in either their pore structure (adsorbents) or in solution (absorbents). Membrane separators utilize a semipermeable membrane that allows water vapor to pass through but blocks the free passage of air, creating a region of much higher relative humidity than the environment. Technologies that concentrate water vapor must utilize an additional condensation step to produce liquid water. The advantage gained by these advancements is their ability to provide access to clean water for even the most arid climates around the globe, where the need for secure water is the greatest. Increased demand for water has led scientists and engineers to develop novel materials and climb the energy ladder, overcoming the energy requirements of atmospheric water harvesting. Many research groups around the world are working quickly to develop new technologies and more efficient water harvesters.
21-30 of 342 Results
Article
Review of Rain and Atmospheric Water Harvesting History and Technology
Nathan Ortiz and Sameer Rao
Article
Water as a Merit Good
Michael Hanemann and Dale Whittington
In economics, a merit good is a good which it is judged that an individual or group of individuals should have (at least up to a certain quantity) on the basis of some concept of need, rather than on the basis of ability or willingness to pay. Examples include public elementary education and free hospitals for the poor alongside access to safe, affordable, and reliable water and sanitation. Exactly how a merit good is provided can be subjected to an economic test, but not whether the merit good should be provided. While there are some overlaps in application, the concept of a merit good is distinct from other economic concepts: A merit good may or may not be a public good, and it may or may not involve an externality. However, water and sanitation infrastructure may indeed be viewed as a form of social overhead capital.
A merit good is an economic concept; the human right is an ethical concept—and, sometimes, a legal concept. That said, the concept of a merit good and the judgment that a particular item is a merit good clearly have an ethical component. If one accepts the existence of a human right to water and sanitation, that could certainly motivate a government decision to make the provision of water and sanitation a merit good.
Even if a commodity is deemed to be a merit good, that still leaves open questions: To which group of people should it be provided as a merit good? In what quantity should it be provided? At what price, if any? By whom should it be provided? And how should the cost be funded?
Article
A Review of Alternative Water Supply Systems in ASEAN
Cecilia Tortajada, Kris Hartley, Corinne Ong, and Ojasvee Arora
Climate change, water scarcity and pollution, and growing water demand across all sectors are stressing existing water supply systems, highlighting the need for alternative water supply (AWS) systems. AWS systems are those that have not typically existed in the traditional supply portfolio of a given service area but may be used to reduce the pressure on traditional water resources and potentially improve the system’s resilience. AWS systems have been used for decades, often where traditional systems are unable to maintain sufficient quantity and quality of water supply. Simpler forms of AWS systems, like rainwater harvesting, have been used for centuries. As human population and water demand have increased, AWS systems now play a larger role in the broader supply portfolio, but these systems alone are not able to fully resolve the increasingly complex mix of problems contributing to water stress. Entrenched challenges that go beyond technical issues include low institutional capacity for developing, operating, and maintaining AWS systems; monitoring water quality; more efficiently using available resources; and establishing clear responsibilities among governments, service providers, and property owners. Like traditional water supply systems, AWS systems should be developed within a sustainability-focused framework that incorporates scenario planning to account for evolving natural and institutional conditions. In ASEAN, the adoption of AWS systems varies among countries and provides context-specific lessons for water management around the world. This article provides an overview of AWS systems in the region, including rainwater harvesting, graywater recycling, wastewater reclamation, desalination, and stormwater harvesting.
Article
Ceremonial and Subsistence Water Use
Dale Whittington and Michael Hanemann
Water for cultural and religious purposes, referred to as ceremonial and subsistence (C&S) use, is a distinctive feature of many Indigenous and other communities. Whether this constitutes a legitimate claim for water for an American Indian Tribe in the United States was litigated in the context of a trial to determine the federal government’s obligation to reserve water for Indian Tribes whom it had settled on reservations during the 19th century. Following a U.S. Supreme Court ruling in 1963, the amount of water the federal government was obligated to provide was defined as the quantity of water that could be used to grow crops profitably on the reservation. In 2001, the Arizona Supreme Court adopted a new definition, for Arizona, namely the amount of water that ensured the reservation would be a permanent homeland. However, parts of this 2001 ruling were contradictory and seemed to support the profitable irrigation standard. What the Arizona Supreme Court actually meant was not put to the test until the Hopi water rights trial in 2020. The Hopi Tribe’s water rights claims included a claim for new water to replace diminishing local water supplies in order for the Tribe to continue cultivating traditional varietals of corn and other crops. Hopi agricultural practices date back at least a millennium and are a central part of Hopi culture and religion. The crops are used in cultural and religious ceremonies and are not sold commercially. The Hopi claim for water for irrigation to support C&S cultivation was opposed by the other parties to the case and was rejected by the court.
Article
Basin Development Paths: Lessons From the Colorado and Nile River Basins
Kevin Wheeler
Complex societies have developed near rivers since antiquity. As populations have expanded, the need to exploit rivers has grown to supply water for agriculture, build cities, and produce electricity. Three key aspects help to characterize development pathways that societies have taken to expand their footprint in river basins including: (a) the evolution of the information systems used to collect knowledge about a river and make informed decisions regarding how it should be managed, (b) the major infrastructure constructed to manipulate the flows of water, and (c) the institutions that have emerged to decide how water is managed and governed. By reflecting on development pathways in well-documented transboundary river basins, one can extract lessons learned to help guide the future of those basins and the future of other developing basins around the world.
Article
Ecological Water Management in Cities
Timothy Beatley
Managing water in cities presents a series of intersecting challenges. Rapid urbanization, wasteful consumption, minimal efforts at urban or ecological planning, and especially climate change have made management of urban water more difficult. Urban water management is multifaceted and interconnected: cities must at once address problems of too much water (i.e., more frequent and extreme weather events, increased riverine and coastal flooding, and rising sea levels), but also not enough water (e.g., drought and water scarcity), as well as the need to protect the quality of water and water bodies.
This article presents a comprehensive and holistic picture of water planning challenges facing cities, and the historical approaches and newer methods embraced by cities with special attention to the need to consider the special effects of climate change on these multiple aspects of water and the role of ecological planning and design in responding to them. Ecological planning represents the best and most effective approach to urban water management, and ecological planning approaches hold the most promise for achieving the best overall outcomes in cities when taking into account multiple benefits (e.g., minimizing natural hazards, securing a sustainable water supply) as well as the need to protect and restore the natural environment. There are many opportunities to build on to the history of ecological planning, and ecological planning for water is growing in importance and momentum. Ecological planning for water provides the chance to profoundly rethink and readjust mankind’s relationship to water and provides the chance also to reimagine and reshape cities of the 21st century.
Article
The Environmental History of the Antarctic
Sebastian Grevsmühl
The environmental history of the polar regions, and in particular of Antarctica, is a rather recent area of inquiry that is in many ways still in its infancy. As a truly multidisciplinary research field, environmental history draws much inspiration from a large diversity of fields of historical and social research, including economic history, diplomatic history, cultural history, the history of explorations, and science and technology studies. Although overarching book-length studies on the environmental history of Antarctica are still rare, historical scholars have already conducted many in-depth case studies related mostly to three major interrelated research topics: Antarctic governance, natural resource exploitation, and tourism. These recent historical efforts, carried out mostly by a new generation of historians, have thus far allowed the proposal of several powerful counternarratives, challenging the frequent yet erroneous assertion that environmental protection and conservation were completely absent from Antarctic affairs before the 1970s. In so doing, environmental historians started offering a much more complex and nuanced account of what is frequently referred to as the “greening” of Antarctica, going well beyond “declensionist” narratives and conservation success stories that commonly pervade not only environmental histories but also public discourse. Indeed, all recent historical studies agree that there is nothing inevitable about the “greening” of Antarctica, nor are conservation and environmental protection its natural destiny. Science, politics, imperialism, capitalism, and imaginaries all have played their part in this important history, a history that remains still largely to be written.
Article
Statistical Scaling of Randomly Fluctuating Hierarchical Variables
Shlomo P. Neuman, Monica Riva, Alberto Guadagnini, Martina Siena, and Chiara Recalcati
Environmental variables tend to fluctuate randomly and exhibit multiscale structures in space and time. Whereas random fluctuations arise from variations in environmental properties and phenomena, multiscale behavior implies that these properties and phenomena possess hierarchical structures. Understanding and quantifying such random, multiscale behavior is critical for the analysis of fluid flow as well as mass and energy transport in the environment.
The multiscale nature of randomly fluctuating variables that characterize a hierarchical environment (or process) tends to be reflected in the way their increments vary in space (or time). Quite often such increments (a) fluctuate randomly in a highly irregular fashion; (b) possess symmetric, non-Gaussian frequency distributions characterized by heavy tails, which sometimes decay with separation distance or lag; (c) exhibit nonlinear power-law scaling of sample structure functions (statistical moments of absolute increments) in a midrange of lags, with breakdown in such scaling at small and large lags; (d) show extended power-law scaling (linear relations between log structure functions of successive orders) at all lags; (e) display nonlinear scaling of power-law exponent with order of sample structure function; and (f) reveal various degrees of anisotropy in these behaviors. Similar statistical scaling is known to characterize many earth, ecological, biological, physical, astrophysical, and financial variables.
The literature has traditionally associated statistical scaling behaviors of the aforementioned kind with multifractals. This is so even though multifractal theory (a) focuses solely on statistical scaling of variable increments, unrelated to statistics of the variable itself, and (b) explains neither observed breakdown in power-law scaling at small and large lags nor extended power-law scaling of such increments. A novel Generalized sub-Gaussian scaling model is introduced that does not suffer from such deficiencies, and some of its key aspects are illustrated on microscale surface measurements of a calcite crystal fragment undergoing dissolution reaction due to contact with a fluid solution.
Article
Transcontinental Meteorology Infrastructures From Ancient Mesopotamia to the Early Modern Age
Robert-Jan Wille
The current global infrastructure of meteorology partly builds on older transcontinental structures of weather science and meteorological philosophy. For several millennia, the large belt stretching from East Asia, through mountains, silk roads, and the Indian Ocean, to the seas and river deltas where Western Eurasia and North Africa border on each other, has formed a key region. From Ancient Mesopotamia to the 16th century, a continuous and multi-site infrastructure emerged that was organized around meteorological texts, including not only scrolls, papyri, and manuscripts, but also ideas and concepts, as well as meteorological writers and readers traveling between institutions and storehouses.
Not considering the long history of orally transmitted pre-Mesopotamian weather knowledge, the first large-scale textual infrastructures were inseparable from astronomical tabulation and dynastical prognostication. In later millennia, in the city states and empires of Greece, Rome, China, and India, “meteorology” became a distinct subject, with its own language and concepts, even though it remained allied to agriculture and statecraft as knowledge practices. At the beginning of the Common Era, the first distinct meteorological instruments appeared, first in East Asia and later in the Near East and Greece.
In the 15th and 16th centuries, new regions were added to this knowledge infrastructure, with or without force, making it almost global: the Atlantic and Pacific Oceans, their Eurasian and African shores, and the Americas. This changed the power dynamics, with European empires controlling the transatlantic infrastructures of knowledge and labor. Ideas that were transcontinental in origin now became part of a Western European program to conquer the globe.
Article
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.
