What is an aquifer?

An aquifer is a layer of underground rock, sand, or gravel that is saturated with water and can yield usable amounts of water when wells are drilled into it. These underground water-bearing layers are capable of supplying water to wells, springs, and other surface water sources. Aquifers are an important source of freshwater for human consumption, irrigation, and industrial uses. They can be replenished naturally by rainfall and other forms of precipitation, or artificially through processes such as injection of water into the ground or recharge through infiltration basins. However, excessive withdrawal of water from an aquifer can lead to depletion and eventually drying up of the aquifer.