When trapped water in an aquifer is surrounded by layers of impermeable rock or clay, which apply positive pressure to the water, it is known as:
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. artesian aquifer.
An artesian aquifer is a type of confined aquifer where water is trapped between layers of impermeable rock or clay. These surrounding layers exert positive pressure on the water, causing it to rise above the aquifer level when tapped by a well, sometimes even flowing naturally to the surface.
Other options:
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Unconfined aquifer: Has no overlying impermeable layer; water seeps directly from the surface.
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Unsaturated aquifer: Contains both air and water; not fully saturated.
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Perched aquifer: Forms above the main water table due to a localised impermeable layer.