Simulation of seawater intrusion in the Nile Delta aquifer under the conditions of climate change

Abstract

The problem of seawater intrusion is encountered in almost all coastal aquifers. Because of its higher density, the seawater migrates inland into freshwater aquifers even without any pumping activities. Excessive pumping of groundwater would accelerate seawater intrusion. Climate change and sea level rise represent critical parameters affecting the rate and degree of seawater intrusion. In this paper, a coupled transient finite element model for simulation of fluid flow and solute transport in saturated and unsaturated soils (2D-FEST) is employed to study the seawater intrusion in the Nile Delta aquifer. The results of the current model are compared to results of SEAWAT for model verification. The (2D-FEST) model is used to investigate seawater intrusion considering the impacts of climate change. Three scenarios are studied: (a) rise in sea level, (b) decline of the piezometric head at the land side due to excessive pumping, and (c) combination of sea level rise and decline of the piezometric head. The results show that the rise in the sea level has a significant effect on the position of the transition zone. The third scenario represents the worst case under which the groundwater quality would deteriorate in large areas of the Nile Delta aquifer.

Hydrochemical Characteristics and Irrigation Suitability Evaluation of Groundwater with Different Degrees of Seawater Intrusion

“…So far, dozens of countries and regions have studied seawater intrusion, such as the United States, Netherlands, South Korea, Japan, China, and so on. In recent years, research on seawater intrusion has mainly focused on numerical simulation, the impact of climate change on seawater intrusion, and the prevention and control methods of seawater intrusion; for example, the authors of [19], using laboratory experiment and numerical simulation methods, studied the effect of aquifer recharge and flow barriers on seawater intrusion and found that recharging the toe of the saltwater wedge was more effective in preventing seawater intrusion; the authors of [20] studied the seawater intrusion of the Nile Delta aquifer under climate change conditions and found that the rise of sea level has a significant effect on seawater intrusion; the authors of [21] used an analytical solution to study the effect of aquifer slope on seawater intrusion and found that aquifers thin towards the sea are most susceptible to sea level rise and seawater intrusion.…”

The Issue of Groundwater Salinization in Coastal Areas of the Mediterranean Region: A Review

“…Besides the physically based density dependent numerical models that need a large number of field data to be calibrated, there has recently been a growing number of papers that have employed the surrogate models, such as non-linear regressive techniques, to describe the SWI phenomenon [160][161][162][163][164], or using simple spreadsheet macros to plot the hydrochemical facies evolution [165]. In general, numerical models have been widely used to quantify the different origins of salinization via density dependent flow and transport models [166][167][168][169][170][171][172][173][174][175]. Finally, only a few papers have been conducted involving the coupling major ions, isotope data, or geophysical investigations to achieve a multidisciplinary model construction [176,177].…”

Assessing the Fresh–Saline Groundwater Distribution in the Nile Delta Aquifer Using a 3D Variable-Density Groundwater Flow Model

“…To counteract/manage/anticipate these threats, a better understanding of the present hydrogeological conditions of the NDA is required: Its geological condition, its groundwater dynamics, its relation with the surface water system, and its current salinity concentration distribution. In recent decades, different aspects of the Nile Delta have been investigated through research on geology [7][8][9], land subsidence and SLR [10,11], geochemistry [12,13], and SWI processes in the NDA and its hydrogeology [14]. Since the 1980s, researchers have used different numerical approaches to delineate fresh and saline groundwater interfaces.…”