نتایج جستجو برای: loss of fresh water resources
تعداد نتایج: 21255248 فیلتر نتایج به سال:
rivers and runoff have always been of interest to human beings. in order to make use of the proper water resources, human societies, industrial and agricultural centers, etc. have usually been established near rivers. as the time goes on, these societies developed, and therefore water resources were extracted more and more. consequently, conditions of water quality of the rivers experienced rap...
drought is transient phenomenon , slow , repetitive and integral part of the climate of each region. drought begins with a substantial reduction in precipitation over the long-term average rainfall and over time, reduced soil moisture and surface and ground water resources will continue to decrease. this phenomenon is the most important in bakhtegan basin because of its importance in strategic ...
the caspian sea contains great resources of oil and gas. the caspian sea is a 700- mile- long body of water in central asia, land located between azerbaijan, iran, kazakhstan, russia and turkmenistan. iran was challenges and opportunities in the caspian region. key question in this thesis includes three section that first question, opportunities of iran in the caspian region, second question ch...
in civil engineering concrete is a material combined of hydraulic cement, sand, gravel and water. gravel and sand compose 60 to 70 percent of concrete. these aggregates support compression force of concrete. cement paste acts as glue to stick grain together. in bushehr factories producing aggregates do not operate according to astm standards, so that fineness modulus (fm) of the produced sands ...
The collection of fog water is a simple and sustainable technology to obtain fresh water for afforestation, gardening, and as a drinking water source for human and animal consumption. In regions where fresh water is sparse and fog frequently occurs, it is feasible to set up a passive mesh system for fog water collection. The mesh is directly exposed to the atmosphere, and the foggy air is pushe...
One of the main problems experienced by the islanders of Lakshadweep is associated with the availability of fresh water for drinking purpose. The scarcity of fresh water is due to the peculiar hydrologic, geologic, geomorphic and demographic features. Proper understanding of the groundwater condition, in terms of availability, distribution and quality, is very important to meet the increasing d...
Land reclamation in coastal areas may have a significant effect on local ground water systems. Steady-state analytic solutions based on Dupuit and Ghyben-Herzberg assumptions are derived to evaluate this effect. Two situations are considered, both with ground water flow resulting from precipitation recharge: the coastal aquifer of an extensive landmass and an island. The results show that after...
With the rapidly increasing demands on water resources, fresh water shortage has become an important issue affecting the economic and social development in many countries. As one of the main technologies for producing fresh water from saline water and other wastewater sources, reverse osmosis (RO) has been widely used so far. However, a major challenge facing widespread application of RO techno...
There is a gradual decline in soil fertility due to its continue use in farming. This necessitates developing new strategies of management programs to recharge soil with nutrients. From review it has been found that reuse of industrial effluents (wastewater) in agriculture can be a good mode to conserve soil nutrients. It may offer a way to fulfill irrigation water demands also. The major chall...
There is no common understanding of the minimum per capita fresh water requirement for human health and economic and social development. Existing estimates vary between 20 and 4,654 l/c/d, however, these estimates are methodologically problematic as they consider only human consumptive and hygiene needs, or they consider economic needs but not the effects of trade. Reconsidering the components ...
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