Tide-induced fluctuations of salinity and groundwater level in unconfined aquifers – Field measurements and numerical model

•We examine the tidal effect on salinity and water table in coastal aquifers.•Field and numerical model results are analyzed and time-lag of head and salinity is calculated.•Time-lag of salinity in the fresh-saline interface is similar to the water table.•Time-lag of salinity is larger than that of the hydraulic head at the same place.•Field and model results validate the conceptual mechanism suggested by Levanon et al. (2016).