نوع مقاله : مقاله مروری
نویسندگان
1 آب منطقه ای مرکزی
2 دانشگاه کردستان، گروه علوم زمین
3 شرکت آب منطقه ای مرکزی
4 علوم زمین، علوم پایه، دانشگاه کردستان، سنندج ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
The water table is used by hydrologists as a key variable in different cases. Superficially, it has a simple definition and is conventionally defined as a level where the saturated and unsaturated zones are separated in a porous media. However, a closer examination demonstrates that many theories concerning the water table are not often as simple as they are assumed to be, and there are several definitions for it based on environmental conditions. The hydraulic head is the basis for the interpretation of groundwater flow, quantification of aquifer features, and calibration of flow models that are determined based on a measurement of the water table in piezometers. This research reviews the concept of groundwater table and the phenomena effect on it. This includes perched and inverted water table, the phenomenon of gas bubbles in the saturated zone under the groundwater table, water table in media with dual and multiple porosity, the impact of barometric pressure fluctuation in water table measurement in confined and unconfined aquifers, and the effects of density and temperature on water table measurement. Moreover, the study discusses some of the methods used for water table measurement, their relative applications, and ways to avoid measurement errors. According to a review of the available resources, the water table is most accurately defined as the level where pressure is equal to atmospheric pressure, and the most significant and accurate methods of water table measurement include the use of measurement tapes and pressure transducers, although the most important measurement errors concern the thermal expansion and contraction of the steel tape and its coating and the strain arising from the weights of the tape and the plumb bob attached to it.
کلیدواژهها [English]
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