The Water Table or Phreatic Surface

The pores within the zone of saturation are filled with water, generally referred to as phreatic water. The upper surface of this zone is therefore known as the phreatic surface but is more commonly termed the water table. Above the zone of saturation is the zone of aeration 

A perched water table is one that forms above a discontinuous impermeable layer such as a lens of clay in a formation of sand, the clay impounding a water mound. 

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The water table (or phreatic surface) is not a boundary separating zones where seepage and pore pressures exist from those where they don t exist it is simply a line of zero pore pressure. 

Shallow wells are those that are less than 100 ft deep. Such wells are not particularly desirable for municipal supplies because the aquifers they tap are likely to fluctuate considerably in depth, making the yield somewhat uncertain. Municipal wells in such aquifers cause a reduction in the water table (or phreatic surface) that affects nearby private wells, which are more likely to utilize shallow strata. Such interference with private wells may result in damage suits against the community. Shallow wells may be dug, bored, or driven ... 

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