Steady-state semi-analytical solutions for assessing the shape of the freshwater–seawater interface induced by a finite-sized underground physical barrier and a pumping well in a sloping coastal aquifer
Abstract
Underground physical barriers are recognized as an effective engineering technology for preventing seawater intrusion into coastal aquifers. However, most previous studies have primarily considered two-dimensional barrier effects (cross‐sectional models). This study proposes steady-state semi-analytical solutions for evaluating the sharp freshwater–seawater interface caused by a finite-sized, impermeable rectangular underground physical barrier that fully penetrates a sloping coastal aquifer, with or without a pumping well. An inland boundary flow condition has been incorporated into all solutions, which allows the hydraulic gradient and the slope of the aquifer to be considered. Solutions are developed for unconfined and confined aquifer conditions and use the Method of Fundamental Solutions to solve the mathematical problem of the barrier. The linearization method used to solve the problem of the sharp freshwater–seawater interface is also discussed. The analysis of the solutions developed includes satisfactory comparisons with numerical modeling and a discussion of other theoretical examples. The results notably highlight that the maximum pumping rate of the well increases with the length of the barrier and with its distance from the coast. As the solutions are based on the Dupuit–Forchheimer assumption and the sharp-interface approximation, they constitute a first-order tool for evaluating the geometry of the freshwater–seawater interface and the maximum safe pumping rate of the well near the barrier (i.e., not influenced by seawater intrusion). They can be implemented as operational tools for the preliminary design of a barrier, thanks to their very short computation time, before more detailed modeling with a spatially distributed 3D model.
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BibTeX
@article{dewandel2026steadystate,
title = {{Steady-state semi-analytical solutions for assessing the shape of the freshwater–seawater interface induced by a finite-sized underground physical barrier and a pumping well in a sloping coastal aquifer}},
author = {Benoît Dewandel and Augustin Gouy and Nicolas Frissant},
journal = {Hydrogeology Journal},
year = {2026},
month = oct,
doi = {10.1007/s10040-026-03177-1},
url = {https://brgm.hal.science/hal-05783914v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Steady-state semi-analytical solutions for assessing the shape of the freshwater–seawater interface induced by a finite-sized underground physical barrier and a pumping well in a sloping coastal aquifer
AU - Benoît Dewandel
AU - Augustin Gouy
AU - Nicolas Frissant
PY - 2026
DA - 2026/10/03
JO - Hydrogeology Journal
DO - 10.1007/s10040-026-03177-1
UR - https://brgm.hal.science/hal-05783914v1
AB - Underground physical barriers are recognized as an effective engineering technology for preventing seawater intrusion into coastal aquifers. However, most previous studies have primarily considered two-dimensional barrier effects (cross‐sectional models). This study proposes steady-state semi-analytical solutions for evaluating the sharp freshwater–seawater interface caused by a finite-sized, impermeable rectangular underground physical barrier that fully penetrates a sloping coastal aquifer, with or without a pumping well. An inland boundary flow condition has been incorporated into all solutions, which allows the hydraulic gradient and the slope of the aquifer to be considered. Solutions are developed for unconfined and confined aquifer conditions and use the Method of Fundamental Solutions to solve the mathematical problem of the barrier. The linearization method used to solve the problem of the sharp freshwater–seawater interface is also discussed. The analysis of the solutions developed includes satisfactory comparisons with numerical modeling and a discussion of other theoretical examples. The results notably highlight that the maximum pumping rate of the well increases with the length of the barrier and with its distance from the coast. As the solutions are based on the Dupuit–Forchheimer assumption and the sharp-interface approximation, they constitute a first-order tool for evaluating the geometry of the freshwater–seawater interface and the maximum safe pumping rate of the well near the barrier (i.e., not influenced by seawater intrusion). They can be implemented as operational tools for the preliminary design of a barrier, thanks to their very short computation time, before more detailed modeling with a spatially distributed 3D model.
SN - 1431-2174
SN - 1435-0157
ER -