Analytical approximation for tidal dynamics in coastal aquifers

Recently, considerable effort has been devoted to the studies of water-table fluctuations in coastal aquifers. However, most previous investigations have been based on one-dimensional models that describe the processes in the cross-shore direction alone, assuming negligible along shore variability. A recent study proposed a two-dimensional approximation for tide-induced water table fluctuations that took into account coastline variations. In this study, we further develop this approximation in two ways, by extending the approximation to second-order and by taking into account capillary effects. Our results demonstrate that both effects can markedly influence water table fluctuations. In particular, with the first-order approximation, the tide-induced water table fluctuations could be subject to sizable errors