- Slides: 25
WATER TABLE *The water table is the upper surface of the zone of saturation. *The zone of saturation is where the pores and fractures of the ground are saturated with water. *The water table is the surface where the water pressure head is equal to the atmospheric pressure. It may be visualized as the "surface" of the subsurface materials that are saturated with groundwater in a given vicinity. * The depth to the water table varies according to factors such as the topography, geology, season and tidal effects, and the quantities of water being pumped from the aquifer
Unsaturated Zone The vadose zone, also termed the unsaturated zone, is the part of Earth between the land surface and the top of the phreatic zone, the position at which the groundwater is at atmospheric pressure. Hence, the vadose zone extends from the top of the ground surface to the water table.
Saturated Zone *The phreatic zone, or zone of saturation, is the area in an aquifer, below the water table, in which relatively all pores and fractures are saturated with water. *The phreatic zone defines the lower edge of the vadose zone. *The phreatic zone size, color, and depth may fluctuate with changes of season, and during wet and dry periods
Aquifers are typically saturated regions of the subsurface that produce an economically feasible quantity of water to a well or spring (e. g. , sand gravel or fractured bedrock often make good aquifer materials). *An aquitard is a zone within the Earth that restricts the flow of groundwater from one aquifer to another. A completely impermeable aquitard is called an aquiclude or aquifuge.
A confined aquifer is an aquifer below the land surface that is saturated with water. Layers of impermeable material are both above and below the aquifer, causing it to be under pressure so that when the aquifer is penetrated by a well, the water will rise above the top of the aquifer.
Unconfined Aquifers *Where groundwater is in direct contact with the atmosphere through the open pore spaces of the overlying soil or rock, then the aquifer is said to be unconfined. *The upper groundwater surface in an unconfined aquifer is called the water table. . *Unconfined aquifers are usually recharged by rain or streamwater infiltrating directly through the overlying soil