A general solution for groundwater flow in an estuarine's leaky aquifer system after considering aquifer anisotropy

Abstract

This paper presents an analytical model for describing the tidal effects in a two‐dimensional leaky confined aquifer system in an estuarine delta where ocean and river meet. This system has an unconfined aquifer on top and a confined aquifer on the bottom with an aquitard in between the two. The unconfined and confined aquifers interact with each other through leakage. It was assumed that the aquitard storage was negligible and that the leakage was linearly proportional to the head difference between the unconfined and confined aquifers. This model's solution was based on the separation of variables method. Two existing solutions that deal with the head fluctuation in one‐dimensional or two‐dimensional leaky confined aquifers are shown as special cases in the present solution. Based on this new solution, the dynamic effect of the water table's fluctuations can be clearly explored, as well as the influence of leakage on the behaviour of fluctuations in groundwater levels in the leaky aquifer system. Copyright © 2015 John Wiley & Sons, Ltd.

A general solution for tide‐induced groundwater fluctuation in an estuarine‐coastal confined and unconfined aquifer system

“…The most obvious difference between a confined and unconfined aquifer is that in the unconfined aquifer, when L i and L o are greater, the amplitude of the head fluctuation decays faster than during smaller leakage. The head fluctuations with different tidal‐river and inland aquitard leakage in an unconfined aquifer all propagate more than 500 m and diminish exponentially along the inland direction (Chen et al, ).…”

“…The effects of the anisotropy of confined and unconfined aquifers have a major influence on the tide‐induced head fluctuations in an aquifer system. Chen et al () derived an analytical model for tidal effects in a two‐dimensional leaky confined aquifer system and showed that high anisotropy allowed the tidal wave to propagate further in the unconfined and confined aquifers. Figure a indicates that the larger the transmissivity T x , the stronger the wave damping effect on the head fluctuation along the x‐axis.…”

“…In recent decades, a number of studies have been conducted on tide‐induced head fluctuations in coastal and estuarine areas (e.g., Jacob, ; Carr & van der Kamp, ; Parlange, Stagnitti, Starr, & Braddock, ; Sun, ; Li, Barry, Cunningham, Stagnitti, & Parlange, ), aquifers with L‐shaped boundaries (Li & Jiao, ; Li, Jiao, Luk, & Cheung, ), a U‐shaped coastal aquifer (Huang, Chuang, Wang, & Yeh, ), and coastal leaky confined aquifer systems (e.g., Jiao & Tang, ; Li & Jiao, , , , ; Chuang & Yeh, , ; Li, Barry, & Jeng, ; Li, Li, Cheng, & Boufadel, ; Xia et al, ; Asadi‐Aghbolaghi, Chuang, & Yeh, , ; Chen, Chuang, Tan, & Ma, ). Jacob () derived an analytical solution for a one‐dimensional coastal aquifer system to describe the tide‐induced groundwater head fluctuation.…”

“…The confined aquifer extended over a finite distance under the sea and terminated with an outlet capping. Chen et al () extended the research of Jiao and Tang (, ) and Jeng, Li, and Barry () to an analytical model to describe the tidal effects in a two‐dimensional leaky confined aquifer system in an estuarine delta where the ocean and river meet. Their solution also discussed the impact factors of head fluctuations, such as anisotropy and leakage.…”

Modeling Tide–induced Groundwater Response in a Coastal Confined Aquifer Using the Spacetime Collocation Approach

“…Figure 5 shows the correctness for the SCA. The MAE associated with the SCA is of the order of -16 10 8.9 × . It is obvious that the SCA may acquire highly accurate results.…”