An aquifer is an underground layer of rock that holds groundwater. Groundwater is rain or melted snow that has seeped into the ground and is held there. Aquifers are filled slowly. For this reason, aquifers can dry up when people drain them faster than they can be refilled—a process called aquifer depletion. Aquifers can be drained by man-made wells or they can flow out naturally in springs.

Noun

an underground layer of rock or earth which holds groundwater.

aquifer depletion
Noun

process by which people pump more water out of aquifers than can be replaced by rain or snow.

drain
Verb

to empty.

Noun

water found in an aquifer.

Noun

liquid precipitation.

rock
Noun

natural substance composed of solid mineral matter.

seep
Verb

to slowly flow through a border.

snow
Noun

precipitation made of ice crystals.

spring
Noun

small flow of water flowing naturally from an underground water source.

well
Noun

a hole drilled in the Earth to obtain a liquid or gaseous substance.