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It is the height of the free surface of water above a given point beneath the surface. [4] Pumping level is the level of water in the well during pumping. [8] Specific capacity is the well yield per unit of drawdown. [8] Static level is the level of water in the well when no water is being removed from the well by pumping. [8]
Cross section showing the water table varying with surface topography as well as a perched water table Cross-section of a hillslope depicting the vadose zone, capillary fringe, water table, and the phreatic or saturated zone. (Source: United States Geological Survey.) The water table is the upper surface of the zone of saturation.
Groundwater surface drawdown As the groundwater is pumped out, the effective stress changes, precipitating consolidation , which is often non-reversible. Thus, the total volume of the silts and clays is reduced, resulting in the lowering of the surface.
In geotechnical engineering, watertable control is the practice of controlling the height of the water table by drainage.Its main applications are in agricultural land (to improve the crop yield using agricultural drainage systems) and in cities to manage the extensive underground infrastructure that includes the foundations of large buildings, underground transit systems, and extensive ...
An aquifer is a collection of water underneath the surface, large enough to be useful in a spring or a well. Aquifers can be unconfined, where the top of the aquifer is defined by the water table, or confined, where the aquifer exists underneath a confining bed. [5]
[1] [2] In an unconfined aquifer (water table), this is an actual depression of the water levels. In confined aquifers , the cone of depression is a reduction in the pressure head surrounding the pumped well. When a well is pumped, the water level in the well is lowered.
As the drafting of water continues, the cone increases in radius. Extracting too much water (overdrafting) can lead to negative impacts such as a drop of the water table, land subsidence, and loss of surface water reaching the streams. In extreme cases, the supply of water that naturally recharges the aquifer is pulled directly from streams and ...
Surface-water hydrology is the sub-field of hydrology concerned with above-earth water (surface water), in contrast to groundwater hydrology that deals with water below the surface of the Earth. Its applications include rainfall and runoff , the routes that surface water takes (for example through rivers or reservoirs ), and the occurrence of ...