Conceptualization and simulation of an integrated pump & treat and Aquifer Storage and Recovery (ASR) pilot scheme in a saline aquifer

Managed Aquifer Recharge (MAR) is an increasingly used technique for water storage, for the improvement of groundwater quality and/or the reduction of seawater intrusion in an aquifer (Bouwer 2002). In many European countries and the circum-Mediterranean, a number of MAR plants, of several scales, have been developed in order to enhance reuse and storage of the existing freshwater resources (Sprenger et al. 2017; García-Menéndez et al. 2018). A pilot-scale Aquifer Storage and Recovery (ASR) unit was constructed in the alluvial saline aquifer of Marathon plain (at the NE coast of Attica, Greece), in order to detect the rehabilitation ability of the aquifer in terms of seawater intrusion and freshwater storage. The MAR scheme was developed in accordance with innovative and practical concepts, called Subsurface Water Solutions or Technologies (SWS or SWT) that were generated especially for coastal areas suffering from seawater intrusion and freshwater resources deficiency (subsol.org; Zuurbier et al. 2017). After the unit was constructed, different experiments were conducted to explore any improvements in the salinity and the piezometry of the groundwater. The simulation of the experimental unit, using MODFLOW-2005 USGS code is presented along with several scenarios that were produced, in ModelMuse 3.10 platform, in order to determine the best water injectionabstraction scheme.