Longman Dictionary of Contemporary English
The Collaborative International Dictionary
Water table \Wa"ter ta"ble\
(Arch.) A molding, or other projection, in the wall of a building, to throw off the water, -- generally used in the United States for the first table above the surface of the ground (see Table, n., 9), that is, for the table at the top of the foundation and the beginning of the upper wall.
(Hydraulic Engin.) The upper limit of the portion of the ground wholly saturated with water. The water table may be within a few inches of the surface or many feet below it.
Wiktionary
n. (context geology English) The level, underground, below which the ground is saturated with water
WordNet
n. underground surface below which the ground is wholly saturated with water; "spring rains had raised the water table" [syn: water level, groundwater level]
Wikipedia
The water table is the surface where the water pressure head is equal to the atmospheric pressure (where gauge pressure = 0). It may be conveniently visualized as the "surface" of the subsurface materials that are saturated with groundwater in a given vicinity. However, saturated conditions may extend above the water table as surface tension holds water in some pores below atmospheric pressure. Individual points on the water table are typically measured as the elevation that the water rises to in a well screened in the shallow groundwater.
The groundwater may be from infiltrating precipitation or from groundwater flowing into the aquifer. In areas with sufficient precipitation, water infiltrates through pore spaces in the soil, passing through the unsaturated zone. At increasing depths water fills in more of the pore spaces in the soils, until the zone of saturation is reached. In permeable or porous materials, such as sands and well fractured bedrock, the water table forms a relatively horizontal plane. Below the water table, in the phreatic zone, permeable units that yield groundwater are called aquifers. The ability of the aquifer to store groundwater is dependent on the primary and secondary porosity and permeability of the rock or soil. In less permeable soils, such as tight bedrock formations and historic lakebed deposits, the water table may be more difficult to define.
The water table should not be confused with the water level in a deeper well. If a deeper aquifer has a lower permeable unit that confines the upward flow, then the water level in a well screened in this aquifer may rise to a level that is greater or less than the elevation of the actual water table. The elevation of the water in this deeper well is dependent upon the pressure in the deeper aquifer and is referred to as the potentiometric surface, not the water table.
A water table is a masonry architectural feature that consists of a projecting course that deflects water running down the face of a building away from lower courses or the foundation. A water table may be found near the base of a wall or at a transition between materials, such as from stone to brick.
A water table is a projection of lower masonry on the outside of the wall slightly above the ground. Often a damp course is placed at the level of the water table to prevent upward penetration of ground water.
Usage examples of "water table".
There was perhaps two feet of water in the ditch, due to natural seepage from the high water table.
Maybe the water that passed through the system was itself pumped up from some deeper water table by the motive power of the steam.
They don't want to be underground 'cause the water table's so high where I come from.
It didn't look like the tree roots went deep, which implied the water table was close to the surface, especially with the recent rainfall.
In the desert, water was in the water table under the valley floor.
It was not as deep, but when she tried to dig it out, she found the water table was higher.
The water table lies just eighteen inches below New Orleansthere are no graves in the earth for that reason.