Groundwater storage is the difference between recharge and discharge over the time frames that these prcesses occur, ranging from days to thousands of years. Changes to both groundwater and surface-water levels may ultimately alter the interaction between groundwater and surface water and the interaction between natural and societal water supply and demand.
Artificial recharge has been cnsidered to enhance groundwater storage. Specifically, Managed Aquifer Recharge (MAR) is used in worldwide environments to replenish groundwater to provide a secure and sustainable supply of potable and non-potable water. It relies on natural treatment processes within aquifers.
Retention slows down the lateral flow of groundwater. This helps pond up groundwater and create a large wet buffer in the subsoil. Under such conditions, it is easier to retrieve and circulate water. Retention makes it possible to extend the chain of water uses. With retention, the groundwater table is heightened. A form of groundwater retention is controlled drainage whereby the groundwater tables are increased and decreased depending on the seasonal requirements for flood storage, agricultural or other uses.