Two‐dimensional flow response to tidal fluctuation in a heterogeneous aquifer‐aquitard system

Abstract

In alluvial coastal aquifers, finer sediments are preferentially deposited along the downstream direction, so the hydraulic conductivity is generally heterogeneous and changes with distance from the coastline. To investigate the influence of aquifer heterogeneity on seawater‐groundwater interaction, a new two‐dimensional model characterising groundwater flow in an aquifer‐aquitard system was developed assuming that the hydraulic conductivity of the aquifer linearly increases with the distance from the coastline along the inland direction. A closed‐form analytical solution was derived using the separation‐of‐variables method. Comparing the new solution with the numerical solution by comsol Multiphysics (Sweden) based on the finite‐element method, one can see that the new solution agreed with the numerical solution very well except at the early time. We found that both aquitard leakance and the heterogeneity factor (b) could result in the propagation bias. The propagation bias represents the inconsistency between the theoretical calculation and the observed strong attenuation and small time lag between the head and tide fluctuations. The attenuation decreased with perpendicular distance from the coastline (x‐axis), whereas the time lag increased with distance along the x‐axis. The relationship between the time lag and the distance along the x‐axis seemed to be linear when b was 0.001 m−1, whereas it obeyed a power function when b was greater than 0.01 m−1. Copyright © 2014 John Wiley & Sons, Ltd.

Groundwater response to tidal fluctuations in wedge-shaped confined aquifers

“…Basically, three types of approaches have been employed in order to study such effects. The first approach, referred to as the sub-region model, assumes that the heterogeneous aquifer can be represented by homogeneous sub-regions (Wang et al 2015). Trefry (1999) presented comprehensive solutions for an aquifer consisting of an arbitrary number of contiguous homogeneous zones subjected to sinusoidal linear boundary conditions.…”

Cl− as a Chemical Fingerprint of Solute Transport in the Aquitard-Aquifer System of the North Jiangsu Coastal Plain, China

“…Diffusing testing results were analyzed using the COM-SOL software (COMSOL 4.4, Burlington, MA, USA) [45,46] [50].…”

On River‐Aquifer Exchange Flow With Irregular and Semipervious Bank

“…Bank storage is a critical process of interactions between surface water and groundwater, as it can not only attenuate and delay the peaks of floods (Ferencz et al., 2019; Liang et al., 2018; Xie et al., 2016), but also can greatly enhance the biogeochemical processes in hyporheic zones, thus is beneficial for supporting overall health and functions of aquatic environments (Boano et al., 2014; Harvey & Gooseff, 2015). The river‐aquifer exchange during bank storage processes has been widely investigated since the 1960s, and many important models have been proposed (e.g., Cooper & Rorabaugh, 1963; Hall & Moench, 1972; Hunt, 1990; Moench et al., 1974; Pinder & Sauer, 1971; Wang et al., 2015; Zlotnik & Huang, 1999; and others). However, a common assumption of vertical banks was used in many of those studies.…”