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Topic Review
Water Stress and Water Footprint
Physical water stress and scarcity are often used interchangeably, or the exact nature of the underlying data is not clearly defined or justified (e.g., water use versus consumption versus withdrawal). A number of authors have noted that there is no widely accepted definition for physical water stress and scarcity.   Comparing different definitions of water stress and scarcity, they seem to be converging on the definition given by the CEO Water Mandate (A NGO affiliated with the United Nations), who defines water scarcity as lack of physical abundance of freshwater resources without considering whether water is suitable for use, and water stress as lack of ability to meet human and ecological demand for freshwater, in terms of water quantity and quality and accessibility to water.
  • 917
  • 01 Feb 2022
Topic Review
Water Splitting by MnOx/Na2CO3 Reversible Redox Reactions
Hydrogen is referred to as a secondary energy carrier, made from a primary energy source (nowadays, ~95% from fossil fuels). The global transition to hydrogen as an energy carrier accompanies the rise in required “green” energy. The H2 production by the different MnOx/Na2CO3 reactants was repeated in the solar reactor. Temperatures of the outer reactor wall were limited to below ~1000 °C (strength limitation of the Incoloy construction material). Due to the inertia of the heliostat focusing, temperatures in the bed varied between about 760 and 790 °C (average 775 °C) and between 815 and 835 °C (average 825 °C). Mostly, the first H2 production cycle was investigated. For the cold mix Mn3O4/Na2CO3, the reactants after H2 production were regenerated for 6 h at an average 825 °C using pure CO2.
  • 305
  • 06 Jul 2022
Topic Review
Water Service Provision
The controversy between the performance of public and private ownership of water and wastewater services is common worldwide. In most cases, this discussion is biased due to ideological issues or insufficiency or inconsistency of information. This study aims to compare the performance of private water utilities with that of public water utilities, using rich, robust, and audited information from Portuguese operators. The benchmarking exercise focuses on three distinct areas, namely, the efficiency and effectiveness of the investments made, the quality of service provided, and the tariffs and prices implemented. From the analysis performed, it is concluded that, on average, the performance of private water utilities exceeds that of public water utilities, and prejudice in most cases is unjustified regarding private ownership. Anyway, water, as an essential service, should always be provided, regardless of utility ownership.
  • 1.2K
  • 27 Oct 2020
Topic Review
Water Scarcity
Water scarcity, defined as long-term water imbalances occurring when the level of water demand exceeds natural water availability and supply capacity, is expected to pose high risks to both societies and economies in the next decade.
  • 1.2K
  • 03 Feb 2022
Topic Review
Water Reuse Treatment Technologies
Treating water for water reuse typically involves treating wastewater in several steps consisting of preliminary treatment, primary treatment, and secondary treatment. Tertiary treatment and advanced treatment may be needed for water reuse purposes. 
  • 1.0K
  • 18 May 2023
Topic Review
Water Reuse
Wastewater treatment and reuse has passed through different development stages with time. Based on archeological evidence and time records, the awareness of the Greeks regarding land disposal, irrigation, and water reuse is highlighted. The latter has evolved into a plethora of applications, with Direct Potable Reuse (DPR) representing one of the last modern frontiers.
  • 229
  • 25 Sep 2023
Topic Review
Water Retention on Mathematical Surfaces
Water retention on mathematical surfaces is the catching of water in ponds on a surface of cells of various heights on a regular array such as a square lattice, where water is rained down on every cell in the system. The boundaries of the system are open and allow water to flow out. Water will be trapped in ponds, and eventually all ponds will fill to their maximum height, with any additional water flowing over spillways and out the boundaries of the system. The problem is to find the amount of water trapped or retained for a given surface. This has been studied extensively for two mathematical surfaces: magic squares and random surfaces. The model can also be applied to the triangular grid.
  • 613
  • 01 Nov 2022
Topic Review
Water Resources Research in the Souss-Massa Basin, Morocco
Most recent studies confirm a decreasing trend in water resources availability in the northern African region; the high competition between the sectors that use this vital resource, and the changing climate are considered as the main factors behind this situation. Under such very dynamic interactions between the natural resources, climate and the socioeconomic sectors, scientists from different perspectives have a challenging task to provide up-to-date and reliable insights to guide potential sustainable management strategies. Through the case of the Souss-Massa, the present research provides state of the art scientific research on water resources. The maps of publications analyzed showed that researchers working in the area focus more on the study of the quality, chemical processing and the impacts of climate change on the availability of water resources. The results showed that Souss-Massa is a region where an important amount of research on climate and water has been carried out. Hence, to keep up with the rapid evolution of land use and other anthropogenic actions in the basin there remain several gaps in knowledge and constraints to address.
  • 755
  • 07 May 2022
Topic Review
Water Resource Management
Water resource management is the activity of planning, developing, distributing and managing the optimum use of water resources. It is an aspect of water cycle management. Water is essential for our survival. The field of water resources management will have to continue to adapt to the current and future issues facing the allocation of water. With the growing uncertainties of global climate change and the long-term impacts of past management actions, this decision-making will be even more difficult. It is likely that ongoing climate change will lead to situations that have not been encountered. As a result, alternative management strategies, including participatory approaches and adaptive capacity are increasingly being used to strengthen water decision-making. Ideally, water resource management planning has regard to all the competing demands for water and seeks to allocate water on an equitable basis to satisfy all uses and demands. As with other resource management, this is rarely possible in practice so decision-makers must prioritise issues of sustainability, equity and factor optimisation (in that order!) to achieve acceptable outcomes. One of the biggest concerns for our water-based resources in the future is the sustainability of the current and future water resource allocation. As water becomes scarce, the importance of water management grows vastly—finding a balance between humans' needs and the essential step of water resources sustainability in the environment.
  • 1.4K
  • 03 Nov 2022
Topic Review
Water Resilience
Analyze from a holistic and comprehensive perspective the water resource in the water cycle context and its relationships in the various environments for the strategic approach to resilience as a way to sustainability.
  • 877
  • 03 Feb 2022
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