Aquifer!
An aquifer is a porous, water-saturated layer of sand, gravel, or bedrock through which groundwater flows. At some point, there is usually a layer of ground that resists water penetration known as the confining bed. This layer is typically either finer textured and denser than the above layers of soil; or a consolidated rock (Rock that contains very few holes or cracks for water to get through).
When confining layers exist both above and below an aquifer, it is termed as "confined aquifer".
Wells can be drilled into the aquifers and water can be pumped out to help meet various human needs.
When the water table of an aquifer is higher than the ground surface and there is sufficient pressure, water is forced out of the ground at a weak point which gives birth to a "spring".
A confined aquifer that has pressure built up inside which forces water out of a well without the need for pumping is known as an "artesian aquifer".
Precipitation eventually adds water into the porous rock of the aquifer in a process known as recharging.
