"An aquifer is a body of rock and/or sediment that holds groundwater. Groundwater is the word used to describe precipitation that has infiltrated the soil beyond the surface and collected in empty spaces underground.
There are two general types of aquifers: confined and unconfined. Confined aquifers have a layer of impenetrable rock or clay above them, while unconfined aquifers lie below a permeable layer of soil.
Many different types of sediments and rocks can form aquifers, including gravel, sandstone, conglomerates, and fractured limestone. Aquifers are sometimes categorized according to the type of rock or sediments of which they are composed.
A common misconception about aquifers is that they are underground rivers or lakes. While groundwater can seep into or out of aquifers due to their porous nature, it cannot move fast enough to flow like a river. The rate at which groundwater moves through an aquifer varies depending on the rock’s permeability."
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Suwannee limestone exposure (Florida)
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Physical Aquifer Model
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Aquifer at Aurangabad Caves (India)
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Aquifer with construction rubble in Planegg (Munich)
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Kaminka (Ukraine)
The water may be recharged by local rainfall and/or travel long distances underground - up to thousands of kilometers. There are aquifers in lowland south Asia, such as Bengal and Bangladesh, which originate from the Himalayas, and the long periods underground in certain soil types lead to the problem of arsenic in groundwater.
External links[edit | edit source]
National Geographic - Aquifers