Groundwater Recharge through a Multiaquifer Shaft near a Flooding Stream

Abstract

In this study, a method has been suggested for quantification of unsteady flow into a multiaquifer shaft during passage of a flood wave in a nearby stream. The shaft penetrates two aquifers, which are separated by an aquiclude. During flood events, the water level in the stream rises, and consequently, the water level in the upper unconfined aquifer rises; as a result, the lower aquifer gets recharged through the shaft. By applying image-well theory, the finite aquifer and well system is transformed into an infinite aquifer and well system. A solution for the multiaquifer shaft and stream system for a time variant boundary condition has been obtained by applying the discrete kernel approach, which is based on Duhamel’s superposition principle. The distance of the shaft from the stream, the extent of its penetration into the aquifer to be recharged, and the radius of the shaft govern the volume of recharge for a particular hydrogeologic site.