Previous Year Question
At some places, groundwater below the water table is stored between layers of hard rocks. What is it known as?
Correct Answer: A
Detailed Solution
An aquifer is an underground permeable geological layer or formation that can store groundwater and allow it to move through it. It may consist of sand, gravel, sandstone, limestone, or fractured rock. According to the U.S. Geological Survey (USGS), permeable layers of rock, sand, or gravel that can store and transmit usable quantities of groundwater are called aquifers.
Water stored in an aquifer can be extracted through wells and tube wells. Aquifers are broadly classified into unconfined aquifers and confined aquifers. A confined aquifer may have relatively impermeable layers above and below it, causing the groundwater within it to remain under pressure.