Search results
Results from the WOW.Com Content Network
For a confined aquifer or aquitard, storativity is the vertically integrated specific storage value. Specific storage is the volume of water released from one unit volume of the aquifer under one unit decline in head. This is related to both the compressibility of the aquifer and the compressibility of the water itself.
A cone of depression is a circular area surrounding a well where groundwater levels are reduced from pumping. [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.
A horizontal water balance is applied to a long vertical column with area extending from the aquifer base to the unsaturated surface. This distance is referred to as the saturated thickness , b . In a confined aquifer , the saturated thickness is determined by the height of the aquifer, H , and the pressure head is non-zero everywhere.
For groundwater "potentiometric surface" is a synonym of "piezometric surface" which is an imaginary surface that defines the level to which water in a confined aquifer would rise were it completely pierced with wells. [1] If the potentiometric surface lies above the ground surface, a flowing artesian well results.
Groundwater discharge is the volumetric flow rate of groundwater through an aquifer. Total groundwater discharge, as reported through a specified area, is similarly expressed as: = where Q is the total groundwater discharge ([L 3 ·T −1]; m 3 /s), K is the hydraulic conductivity of the aquifer ([L·T −1]; m/s),
Aquifer is an underground layer of permeable rock or sand, that hold or transmit groundwater below the water table that yield a significant supply of water to a well. [ 4 ] Aquifer test (or a pumping test) is a field experiment in which a well is pumped at a controlled rate and the aquifer's response (drawdown) is measured in one or more ...
An unconfined aquifer has no impermeable barrier immediately above it, such that the water level can rise in response to recharge. A confined aquifer has an overlying impermeable barrier that prevents the water level in the aquifer from rising any higher. An aquifer in the same geologic unit may be confined in one area and unconfined in another.
The fraction of water held back in the aquifer is known as specific retention. Thus it can be said that porosity is the sum of specific yield and specific retention. Specific yield of soils differ from each other in the sense that some soil types have strong molecular attraction with the water held in their pores while others have less.