(1996). Basic Water Requirements for Human Activities: Meeting Basic Needs. Water International: Vol. 21, No. 2, pp. 83-92.

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Basic Water Requirements for Human Activities: Meeting Basic Needs

A critical analysis of the present situation on the global water resources assessment is made. Basic data and methodological approaches used by the author for the assessment and prediction of water resources, water use and water availability on the global scale are briefly described. On the basis of data generalization of the world hydrological network new data are given on the dynamics of renewable water resources of the continents, physiographic and economic regions, selected countries as well as on the river water inflow to the world ocean. The results of the assessments for the 20th century and for the future before 2010–2025 on the water supply for municipal, industrial and agricultural needs as well as an additional evaporation from reservoirs are presented. Loads on water resources and water availability depending on socio-economic and phisiographic factors are analyzed; regions of water scarcity and water resources deficit are discovered. Possible ways of water supply improvement and elim...

http://bateni.persiangig.com/document/Water%20Resources%20(1)%20MS/Water%20International%20Volume%2025%20issue%201%202000%20%5bdoi%2010.1080_02508060008686794%5d%20Shiklomanov,%20Igor%20A.%20--%20Appraisal%20and%20Assessment%20of%20World%20Water%20Resources.pdf

Appraisal and Assessment of World Water Resources

https://www.ircwash.org/sites/default/files/Sullivan-2002-Water.pdf

Calculating a Water Poverty Index

A shortage of fresh water is one of the acute challenges facing the world today. An energy-efficient approach to converting sea water into fresh water could be of substantial benefit, but current desalination methods require high power consumption and operating costs or large-scale infrastructures, which make them difficult to implement in resource-limited settings or in disaster scenarios. Here, we report a process for converting sea water (salinity approximately 500 mM or approximately 30,000 mg l(-1)) to fresh water (salinity <10 mM or <600 mg l(-1)) in which a continuous stream of sea water is divided into desalted and concentrated streams by ion concentration polarization, a phenomenon that occurs when an ion current is passed through ion-selective membranes. During operation, both salts and larger particles (cells, viruses and microorganisms) are pushed away from the membrane (a nanochannel or nanoporous membrane), which significantly reduces the possibility of membrane fouling and salt accumulation, thus avoiding two problems that plague other membrane filtration methods. To implement this approach, a simple microfluidic device was fabricated and shown to be capable of continuous desalination of sea water (approximately 99% salt rejection at 50% recovery rate) at a power consumption of less than 3.5 Wh l(-1), which is comparable to current state-of-the-art systems. Rather than competing with larger desalination plants, the method could be used to make small- or medium-scale systems, with the possibility of battery-powered operation.

Direct seawater desalination by ion concentration polarization

Coping with Water Scarcity

This report examines the effect of population size growth distribution and consumption patterns on renewable water supplies. Even though more than 66% of this planet is covered with water fresh water makes up only 2.5% of the entire water supply and 69% of that is in the polar ice caps. These figures take on even more meaning as the population increases. The rate at which the global hydrologic cycle renews or replenishes fresh water resources determines the availability of fresh water for human use. Evaporative demand and the timing and location of precipitation contribute greatly to its availability. The greatest drain on water supplies is agriculture (69% of all use) followed by industry and energy (23%) and household use (8%). Desalination of our oceans has been hailed as a technology providing an inexhaustible water supply but extracting salt from seawater is expensive and depends on nonrenewable pollution-causing fossil fuels. Acute water shortages have already plagued some countries regions and municipalities. Europe and North America could not have industrialized had it not been for dependable sources of abundant water. Yet many developing countries do not have such access making economic development more difficult for them to achieve. Countries with less than 1700 cubic meters/person less than 1000 cubic meters/person and less than 500 cubic meters/person face water stress chronic water scarcity and absolute water scarcity respectively. The number of water-scarce countries increased from 7 in 1955 to 20 in 1990 and if population growth projections continue there will be 30-35 water-scarce countries by 2025. Deteriorating water quality caused by raw sewage and industrialized and agricultural wastes further reduces the availability of fresh water and causes numerous diseases (e.g. diarrhea). Access to potable water and sanitation is needed to achieve individual health. Water will eventually overshadow oil as a scarce and precious resource. Population stabilization water conservation and more efficient use of water are the most effective long-term strategies to manage water scarcity.

Robert Engelman

Papers

Sustaining water. Population and the future of renewable water supplies.