Recharge: Water added to a groundwater aquifer. For example, when rainwater seeps into the ground. Recharge may occur naturally through precipitation or surface water or artificially through injection wells or by spreading water over groundwater reservoirs.
Image Source: Dept. of Water and Environmental Regulation, Government of Western Australia,http://www.water.wa.gov.au/urban-water/water-recycling-efficiencies/managed-aquifer-recharge