نتایج جستجو برای: water table level
تعداد نتایج: 1673385 فیلتر نتایج به سال:
it is over two decades that groundwater flow models are routinely implemented for better management of groundwater resources.modeling groundwater flow with the help of the ground water modeling system (gms) in the damghan plain aquifer in northern iran,which experiences declining levels and numerous environmental hazards, has demonstrated that, (a) in the worst case scenario theaquifer will fac...
introduction: better use of water and soil resources in paddy fields, increase in rice production and farmer's income, installation of subsurface drainage system is necessary. the main goalof these systems, are aeration conditions improvement prevention of water logging, yield increase, land use increase and multiuse of the land. in different countries, installation of subsurface drainage cause...
iran is among the world’s arid and semi-arid regions and its demand for water has been increased due topopulation growth, urbanization and the development the economic sectors (industrial and agricultural). inmany of these regions, the lack of planning and the unauthorized use of resources have led to excessiveexploitation and a lower level of groundwater. the usable groundwater for the country...
Floristic studies indicate the abundance of microalgae in northern boreal peatlands, but we know relatively little about their ecology or how they will respond to changes in environmental conditions expected in this region as climate changes. We examined changes in algal community structure at sites exposed to a long-term water-table manipulation, including drought (lowered water-table treatmen...
the planning of water resources is based on the volume of water extracted from the aquifer and accurate estimate of this volume considerably helps to development. in this study, the bayesian networks model using continues and clustering structures was used to simulate the groundwater level of birjand aquifer. bayesian networks was calibrated with five input variables of aquifer recharge, water ...
[1] Areas with a relatively shallow water table are environments where the groundwater plays a key role on the ecosystem function, and important interactions exist between hydrology and ecosystem processes. We propose here an analytical model to study the interactions between rainfall, water table, and vegetation in groundwater-dependent ecosystems. The water table dynamics are studied as a ran...
the impact of meteorological and hydrological drought on groundwater resources in coastal deserts in the south of iran was investigated during 1991-2011, using standardized precipitation index (spi), standardized runoff index (sri), and groundwater resources index (gri). the results indicated that wet and drought spells governed the area in the first and second decades, respectively, which was ...
[1] Water-level increase after rainfall is usually indicative of rainfall recharge to groundwater. This, however, may not be true if the Lisse effect occurs. This effect represents the water-level increase in a well driven by airflow induced by an advancing wetting front during highly intensive rains. The rainwater, which may behave like a lowpermeability lid, seals the ground surface so that t...
The clearing of natural vegetation and irrigation for farming have resulted in rises in the level of groundwater. The rising water table brings salt previously stored deep in the soil profile to the surface, leading to secondary salinisation. Whilst many ecosystems are affected by secondary salinisation, wetlands are considered to be particularly vulnerable because of their low-lying position i...
An analytical one-dimensional model for vertical transmission of barometric pressure in soil unsaturated zone has been developed to examine the effect of free boundary caused by water table. The model is applicable to a special case in which the water table moves in according to the pressure with high barometric efficiency. Ambient sinusoidal pressure fluctuation is assumed at the soil surface....
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