Analyzing the Impact of Rapid Boundary Condition Changes on Salt and Fresh Water Interaction in Coastal Aquifers

Document Type : Research paper

Authors

1 Graduate student of Hydraulic Structures, Urmia University, Urmia, Iran

2 Professor of Hydraulic Structures, Department of Water Engineering, Urmia University, Urmia, Iran

10.22034/hydro.2023.56782.1292

Abstract

This article investigates the impact of sea level fluctuations on numerical modeling of groundwater behavior. The study employs GeoStudio, a finite element numerical model, to calibrate and validate the model using benchmark data from reliable sources. The investigation focuses on changes in saltwater levels under varying rates of increase and decrease. Results indicate that reducing saltwater levels in the numerical model does not affect the estimation of the final dimensions of the saltwater wedge. However, a sudden increase in saltwater levels results in an estimated wedge length that is 4% greater than gradual increases. Furthermore, the research reveals that the system reaches equilibrium fastest when water levels increase or decrease instantaneously. If the minimum time to reach equilibrium during a sudden decrease in water levels is denoted as TR_min, gradual changes in boundary conditions lasting less than half of this time do not impact the equilibrium time. The study also demonstrates that the time required to reach 50% of the advancing length of the saltwater wedge remains independent of the rate of change in saltwater boundary conditions. If the minimum time to reach equilibrium following an instantaneous increase in saltwater levels is denoted as TA_min, and the duration of saltwater level increase is equal to or greater than 1.4TA_min, the time to reach equilibrium of the wedge will be approximately the same as the duration of the saltwater level stabilization.

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References

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Hydrogeology
Volume 8, Issue 2
Publisher
March 2024
Pages 1-14

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