Aquifer recharge is the process by which water enters and replenishes an aquifer, a natural underground layer that holds water. This can occur through various methods, including rainfall, surface water infiltration, and artificial recharge techniques like injection wells or basins. Proper aquifer recharge is essential for maintaining groundwater levels, supporting ecosystems, and providing water for human use. It helps ensure a sustainable supply of fresh water, especially in areas where groundwater is heavily relied upon for drinking, irrigation, and industrial purposes.