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In hydrogeology, an aquifer test (or a pumping test) is conducted to evaluate an aquifer by "stimulating" the aquifer through constant pumping, and observing the aquifer's "response" in observation wells. Aquifer testing is a common tool that hydrogeologists use to characterize a system of aquifers, aquitards and flow system boundaries.
Often the well efficiency is determined from this sort of test, this is a percentage indicating the fraction of total observed drawdown in a pumping well which is due to aquifer losses (as opposed to being due to flow through the well screen and inside the borehole). A perfectly efficient well, with perfect well screen and where the water flows ...
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 observation wells. [5] Cone of depression is a conically-shaped depression that is produced in a water table as a result of pumping water from a well at a given rate. [4]
Hydraulic tomography (HT) is a sequential cross-hole hydraulic test followed by inversion of all the data to map the spatial distribution of aquifer hydraulic properties. Specifically, HT involves installation of multiple wells in an aquifer, which are partitioned into several intervals along the depth using packers. A sequential aquifer test ...
The depth is selected in accordance to aquifer properties. The well filter must be placed in a permeable soil layer. The spacing can be calculated with a well spacing equation using discharge, aquifer properties, well depth and optimal depth of the water table. The determination of the optimum depth of the water table is the realm of drainage ...
The specific storage is the amount of water that a portion of an aquifer releases from storage, per unit mass or volume of the aquifer, per unit change in hydraulic head, while remaining fully saturated. Mass specific storage is the mass of water that an aquifer releases from storage, per mass of aquifer, per unit decline in hydraulic head:
When groundwater is extracted from an aquifer, a cone of depression is created around the well.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.
Most of these questions can be addressed through simulation of the hydrologic system (using numerical models or analytic equations). Accurate simulation of the aquifer system requires knowledge of the aquifer properties and boundary conditions. Therefore, a common task of the hydrogeologist is determining aquifer properties using aquifer tests.