An aquifer is a geological formation that can store and transmit water, typically found underground. It consists of permeable materials, such as sand, gravel, or rock, that allow water to flow through them. Aquifers are crucial sources of freshwater for drinking, irrigation, and industrial use. Water enters aquifers through a process called recharge, where precipitation or surface water seeps into the ground. Aquifers can be classified into two main types: unconfined aquifers, which are directly connected to the surface, and confined aquifers, which are trapped between layers of impermeable rock. Proper management of aquifers is essential to ensure sustainable water supply.