Literature Review on Managed Aquifer Recharge in the Context of Water and Soil Restoration Methods

Abstract

Aquifer recharge occurs naturally through infiltration mechanisms. However, due to changes in the vegetation cover and increasing soil erosion, infiltration rates tend to decrease. The recharge of an aquifer can be managed by facilitating natural infiltration processes and/or by the construction of structures that maintain recharge artificially. Several methods are available to enhance the recharge of an aquifer. The implementation of aquifer recharge schemes can massively increase groundwater levels, which are the best possible long-term storage. Recharge can also help to address objectives such as: improvement of source water quality, recovering of yields, creation of barriers to prevent saline intrusion and/or other contaminants, prevention of land subsidence and the reduction of potentially harmful runoff. Alternatives to recover natural infiltration can be the application of ecosystembased adaptation (EbA) measures or agricultural practices with permanent vegetation cover, such as permaculture. Artificial recharge methods, also called Managed Aquifer Recharge (MAR), can be broadly categorised into in-channel modifications, well, shaft and borehole recharge, induced bank infiltration and rainwater harvesting. The method of recharge depends strongly on the survey of the site. Two key issues have to be considered: the hydrogeological properties of the aquifer and the source of water. Recharge through living topsoil, as in swales, also provides treatment and is by far preferable. In addition, it should not be forgotten that humus rich soil with adequate vegetation cover provides retention and recharge without any technical intervention. However, the techniques described below are often needed to get restoration started at all.