akifer

An akifer, more commonly called an aquifer in English, is a geological formation that can store, transmit, and yield groundwater in usable quantities. It consists of permeable rock or sediment—such as sand, gravel, sandstone, or fractured limestone—that holds water in pore spaces or fractures and allows it to move slowly under natural hydraulic pressure.

There are different types of aquifers. Unconfined aquifers have the water table at or near the surface and are recharged directly by infiltration from precipitation. Confined aquifers are bounded above and below by less permeable layers and can be pressurized, often yielding water under natural hydraulic head. Karst aquifers formed in soluble rocks develop conduits that enable rapid groundwater flow. Aquifers can also be formed by unconsolidated sediments like sand and gravel that store and transmit water readily.

Recharge and discharge describe the water balance of an aquifer. Recharge occurs as precipitation infiltrates or as water from rivers and lakes percolates downward. Discharge returns groundwater to streams, springs, wetlands, or is removed by wells. Groundwater typically moves slowly, with flow rates ranging from centimeters to meters per day in favorable conditions and taking years to decades to respond to changes in recharge.

Aquifers are essential sources of freshwater for drinking, irrigation, and industry. They are vulnerable to contamination from agricultural, industrial, and urban activities, and to overexploitation, which can cause declining water levels, land subsidence, and saltwater intrusion in coastal regions. Sustainable management involves monitoring, protecting recharge areas, artificial recharge where appropriate, and regulating withdrawals to maintain water security.

Globally notable examples include the Ogallala Aquifer in North America, the Great Artesian Basin in Australia, and various limestone and karst aquifers worldwide. In Turkish, the term for aquifer is akifer, used in the same sense.