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Review Article
Effect of Sea Water Intrusion on Nile Delta and
Possible Suggested Solutions
Prepared by:
Mohamed Hassen Elkiki
Civil Engineering Department
Faculty of Engineering
Port Said University.
Egypt
September 2018
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
ii
Table of Contents
Table of contents
ii
List of Figures
iii
Abstract
v
1- Introduction
1
2- Causes and Types of Seatwater Intrusion
2
3- Relation between climate change and salt water intrusion
3
4- Groundwater salinization and monitoring techniques
4
5- Previous studies dealing with sea water intrusion in coastal regions
worldwide
8
6- Sea water intrusion problem in Nile Delta, Egypt
12
6.1- Introduction
12
6.2- Nile Delta Coastal Aquifer
13
6.3- Groundwater Aquifer System in the Nile Delta Region
16
6.4- Assessment of Groundwater Quality in the Nile Delta
18
6.4.1- Remediation of Contaminated Groundwater in Nile Delta
19
6.5- Groundwater Salinity in Nile Delta due to Sea Water Intrusion
20
6.6- Soil Salinization of the Nile delta due to Sea Water Intrusion
20
6.7- Effect of sea level rise (SLR) on Nile Delta coastal area
22
6.8- Effect of Ground water abstraction from Nile Delta Aquifer on
Salinity
23
6.9- Water and Salt Balance in Nile Delta Aquifer
24
6.10- Sea water intrusion in Nile Delta Aquifer
24
6.11- Mitigations and adaptations suggested for the salt water intrusion
problem in Nile Delta Aquifer
32
7- Discussion
35
8- Conclusions
37
9 - Recommendations
38
References
38
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
iii
List of Figures
Figure 1: Groundwater flow patterns and the zone of dispersion in homogeneous
coastal aquifer. Source: water.usgs.gov/ogw/gwrp/saltwater/salt.html
1
Figure 2: Movement of the saltwater interface under the increased saltwater
intrusion due to over pumping and sea level rise. (Abd-Elaty et al 2018)
3
Figure 3: Examples of different types of salinization in ground water and surface
water. (Sanchez et al. 2015)
4
Figure 4: Set up of a VES measurement at the beach. Four reels of wire are used to
connect the measurement unit (the orange device) to the current and
potential electrodes. (Sanchez et al. 2015)
5
Figure 5: The TEC probe in the field and example of a 2D profile with TEC probe
measurements. (Sanchez et al. 2015)
5
Figure 6: Examples of groundwater sampling. (Sanchez et al. 2015)
5
Figure 7: The EM-Slimflex device. (Sanchez et al. 2015)
6
Figure 8: EM 31 instrument in an agricultural field and Some results. (Sanchez et al.
2015)
6
Figure 9: Helicopter-borne frequency-domain electromagnetic (HEM) systems use a
towed installation with small transmitter and receiver coils (about 50 cm).
(Sanchez et al. 2015)
7
Figure 10: Water quality monitoring kit. (Sanchez et al. 2015)
7
Figure 11: SWAPP concept: a low-cost, portable, social, predictive, yet scientifically
sound method for indicating water salinity (and thus for optimising
agriculture a saline environments). (Sanchez et al. 2015)
7
Figure 12: Electrical Resistivity Tomography (ERT) (a) The line (array) of the
electrodes, (b) The terrameter instrument. (Lewkowicz et al. 2016)
8
Figure 13: Helicopter Conducting TDEM Survey. (Lewkowicz et al. 2016)
8
Figure 14: 3D resistivity contour plot referred to salt water (resistivity 4-15 Ωm): a)
May 2013; b) October 2013; c) May 2014. (Tarallo et al., 2014)
11
Figure 15: The Nile delta Aquifer. (Sherif and Al-Rashed, 2001)
13
Figure 16: Geomorphological map for the Nile Delta region. (Nofal, 2015)
13
Figure 17: Cross-section in middle Delta. (Sherif and Al-Rashed, 2001)
14
Figure 18: Quaternary Aquifer (Lower Aquifer) Map. (RIGW, 1992a)
15
Figure 19: Clay Layer Thickness (Upper Aquifer) Map. (Saleh, 2009)
15
Figure 20: Contour lines for the aquifer thickness. (Sherif, 1999)
16
Figure 21: Depth to groundwater of the Nile Delta region in 2008. (Al-Agha et al.,
2015)
16
Figure 22: Piezometric head of the Nile Delta region in 2008. (Al-Agha et al., 2015)
16
Figure 23: Configuration of aquifer systems in the Nile Delta region. (Sakr, 2005)
17
Figure 24: Location map of surface and groundwater samples. (Ghoraba 2009)
18
Figure 25: Areal distribution of total dissolved solids (TDS) in mg/L for
groundwater samples. (Ghoraba 2009)
19
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
iv
Figure 26: Distribution of groundwater salinity in Nile Delta. (FAO, 2009)
20
Figure 27: Categorization of the salt-affected soils in the Nile Delta. (El-Gunidy,
1989)
21
Figure 28: Drainage rates in the Nile Delta in mm/day during 1992/1993. (DRI,
1994)
21
Figure 29: Middle East and North Africa region: Population impacted. (Dasgupta,
et al., 2007)
22
Figure 30: Middle East and North Africa region: Agricultural extent impacted.
(Dasgupta, et al., 2007)
23
Figure 31: Abstraction rates versus time in Nile Delta. (RIGW, 1980, 1992b, 2003,
and 2010, Mabrouk et al., 2013)
23
Figure 32: A schematic presentation of a cross section in the middle Nile Delta
aquifer. (Sherif et al. 2012)
25
Figure 33: Vertical simulation in the Delta aquifer, Equiconcentration lines. (Sherif
and Al-Rashed, 2001)
26
Figure 34: Effect of sea level rise and additional pumping: Equiconcentration lines
under (a) Scenario-1, (b) Scenario-2, and (c) Scenario-(3). (Sherif and Al-
Rashed, 2001)
27
Figure 35: Zones of pumping in the Nile Delta. (Sherif and Al-Rashed, 2001)
27
Figure 36: Seawater intrusion in the vertical sections interpolated from the
horizontal simulations. Sherif et al. (2012)
28
Figure 37: The distance from the shoreline to the saltwater/freshwater showing the
effect of the scenarios on the long run. (Essaway, 2013)
29
Figure 38: Width of the transition zone in the Nile Delta after 50, 100 and 500 years.
(Essaway, 2013)
29
Figure 39: Areal Distribution of TDS for Combination of Three Scenarios Change
by (a) 25 %, (b) 50 % and (c) 100 %. (Abdelaty et al., 2014)
30
Figure 40: Areal view of groundwater levels in Nile Delta aquifer. (Abd-Elhamid et
al., 2016)
31
Figure 41: Horizontal distribution of TDS in Nile Delta aquifer. (Abd-Elhamid et al.,
2016)
31
Figure 42: Vertical distribution of TDS in Nile Delta aquifer. (Abd-Elhamid et al.,
2016)
31
Figure 43: (a): Total Dissolved Solids (TDS) measurements at 400 and 600 m depth
in the Nile Delta and head difference (Dh0) over the anhydrite layer,
expressed in freshwater head (b): Sketched conceptual geological cross-
section of the Nile Delta. (Engelen et al. 20018)
32
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
v
Abstract
Egypt is considered an arid country. The main and almost exclusive source of water is the River
Nile. The second source of water is groundwater whereas a variety of aquifer systems exist. The Nile
Delta aquifer in Egypt is among the largest groundwater reservoirs in the world which is mainly
replenished from irrigation activities. The aquifer is subjected to a severe seawater intrusion problem
from the Mediterranean Sea mainly due to its geometric and geological conditions, limited natural
recharge and overexploitation of the aquifer. A proper management and development of such aquifers
should be directed to satisfy water requirements. Groundwater development in the northern region is
restricted due to the risks of inland movement of saline water / fresh water interface to properly
manage groundwater in this region. To achieve the proper management of groundwater resource in this
region, it is important to understand the patterns of seawater movement and mixing between fresh and
saline groundwater. In order to understand the salinity distribution and seawater movement, the actual
heterogeneity and stratigraphy of the Nile Delta aquifer should be determined. The conventional
modeling concept of the Nile Delta aquifer had assumed the aquifer as a homogenous media of graded
sand and gravel with a clay cap at the top.
Serious environmental problems are emerging in the River Nile basin and its groundwater
resources. Recent years have brought scientific evidence of climate change and development-induced
environmental impacts globally as well as over Egypt. Some impacts are subtle, like the decline of the
Nile River water levels, others are dramatic like the salinization of all coastal land in the Nile Delta –
the agricultural engine of Egypt. These consequences have become a striking reality causing a set of
interconnected groundwater management problems. Massive population increase that overwhelmed the
Nile Delta region has amplified the problem. Many researchers have studied these problems from
different perspectives using different methodologies, following different objectives and, consequently,
arrived at different findings. However, they all confirmed that significant groundwater salinization has
affected the Nile Delta and this is likely to become worse rapidly in the future. This article attempts to
identify and analyze findings of most recent studies regarding salt water intrusion problem in coastal
areas worldwide. Different groundwater salinity monitoring techniques will be presented. Special
focus will be on the most important studies related to the saltwater intrusion problem in the Nile Delta
Aquifer in Egypt. Different modeling approaches concerning future prediction of the behavior of
saltwater intrusion phenomenon under different factors will be discussed. Mitigations and adaptations
suggested by the previous studies and the most applicable ones in Egypt will be presented. The article
recommends that future research should clearly be oriented towards development of a fully integrated
3-D variable density model for the whole Nile Delta aquifer. Continuous standardized monitoring of
the location of the saline interface and the rate of fresh water abstraction through a national integrated
project for the whole area of the Nile Delta are recommended.
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
1- Introduction
Seawater intrusion is the movement of seawater into freshwater aquifers due to natural processes
or human activities. Seawater intrusion is caused by decreases in groundwater levels or by rises in
seawater levels. When you pump out freshwater rapidly, you lower the height of the freshwater in the
aquifer forming a cone of depression. The saltwater rises 40 m for every 1 m of freshwater depression
and forms a cone of ascension as shown in Fig. 1. Intrusion can affect the quality of water not only at
the pumping well sites, but also at other well sites, and undeveloped portions of the aquifer. The
problem of aquifer contamination by seawater intrusion, together with the extent and seriousness of the
problem, is mainly conditioned by three factors: the difference between the respective densities of the
fresh and saltwater, the hydrodynamic properties of the aquifer, and the flow that the aquifer
discharges into the sea. The first two factors are intrinsic to the seawater intrusion problem regardless
of the climate in the region.
Figure 1: Groundwater flow patterns and the zone of dispersion in homogeneous coastal aquifer. Source:
water.usgs.gov/ogw/gwrp/saltwater/salt.html
According to the Integrated Coastal Zone Management (ICZM) of the European Commission,
coastal areas are of great environmental, economic, social, and cultural relevance. Therefore, the
implementation of suitable monitoring and protection actions is fundamental for the preservation and
for assuring the future use of this resource. The phenomenon has been studied extensively all over the
world during more than a century (Werner and Gallagher 2006). It is well known that sea water
intrusion is affected by both natural and anthropogenic processes.
Among all current global, environmental and social changes, climate change, as predicted by
various global climate models (IPCC, 2008), will have severe future impacts in delta areas. There is a
wide range of impacts including: sea level rise, rainfall patterns, floods and droughts frequencies,
salinization, and settlement of land. These impacts may have significant influence on natural resources,
especially water resources – either surface or groundwater. This is particularly problematic for the
Mediterranean coastal areas, and especially the northern Nile Delta Coast in Egypt, where both natural
and socio-economic resources of high value exist and are developed rapidly.
The Nile Delta in Egypt, along with its fringes, covers an area of 22 000 km2 (EGSA, 1997). It is
occupied by the most populated governorates in Egypt. About 60% of Egypt’s population lives in the
Nile Delta region (Sherif, 2001). Agriculture activities are predominant in the region (around 63% of
the total agricultural land) due to the nature of the soil (Dawoud, 2004) and an irrigation system in
place. The Nile Delta aquifer is a vast leaky aquifer that is located between Cairo and the
Mediterranean Sea. The productive aquifer is bound by an upper semi-permeable layer and lower
impermeable rocky layer. The aquifer is recharged by infiltration from excess irrigation water and the
very limited rainfall that infiltrates through the upper clay layer.
The quality of the groundwater in this area may be strongly affected by the impact of the sea level
rise combined with changes of Nile river flows, leading to an increase in the salinity levels of
groundwater (Dawoud, 2004). In addition, the current and future human activities, especially extensive
and unplanned groundwater abstraction are resulting in deterioration of the available groundwater
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
resources. Serious negative socioeconomic impacts can follow as a consequence. This situation
prompts for studying and analyzing the problem thoroughly and identifying flexible adaptation
strategies that can not only mitigate the negative effects of climate change, but also lead to capacity
development for coping with uncertain future changes.
Many water researchers have been interested in the Nile Delta, and they tackled it from different
aspects, focusing on either surface or groundwater. Different tools have been used to characterize,
classify and analyze the groundwater aquifer. Most of the studies assure that climate change is a
significant issue that should be considered with high priority (Sherif, 2001). A number of researchers
investigated the problem of current water quality status of groundwater, but such studies were always
local in nature, not covering the whole Nile Delta. Also, most of the strategies for adaptation measures
focus only on a limited area and do not take into consideration the combined effects that may become
apparent when studying the Nile Delta from regional perspective.
This article attempts to identify and analyze the findings of most recent studies regarding climate
change and development challenges that the Nile Delta faces with particular focus on its groundwater
resources. Hence, the article will focus on presenting state of art research regarding salt water intrusion
in Egypt, and its causes and effects on Nile Delta coastal areas. Finally, different suggested mitigations
and adaptations and the most appropriate ones to be implemented in Egypt will be presented and
discussed.
2- Causes and Types of Saltwater Intrusion
Coastal aquifers lie within some of the most intensively exploited areas of the world. If current
levels of population growth and industrial development are not controlled shortly, “the amount of
groundwater use will increase dramatically, to the point that the control of seawater intrusion becomes
a major challenge to future water resources management engineers. Saltwater intrusion is a serious
problem in the coastal regions all over the world. It may occur due to human activities and by natural
events such as climate change and sea level rise” (Abd-Elaty et al 2018). The main causes of saltwater
intrusion include (Bear et al., 1999):
I - Overabstraction of the aquifers;
II - Seasonal changes in natural groundwater flow;
III - Tidal effects;
IV - Barometric pressure;
V - Seismic waves;
VI - Dispersion; and
VII - Climate change – global warming and associated sea level rise
Overabstraction is considered one of the main causes of saltwater intrusion as shown in Fig. 2.
Some of the previous causes of saltwater intrusion are periodic (e.g. seasonal changes in natural
groundwater flow), some have short-term implications (tidal effects and barometric pressure), and
others have long-term implications (climate changes and artificial influences). Salinization is one of
the most widespread forms of groundwater contamination in the world. Saltwater intrusion poses a
major limitation to the utilization of groundwater resources. The intrusion of seawater should be
controlled to protect groundwater resources from depletion. To take measures to control and prevent
seawater intrusion and to get a clear understanding of the relationship between the consumption of
groundwater and seawater intrusion, in-depth study either from the theoretical point of view or from
the numerical analysis and practical point of view is required. The types of seawater intrusion can be
summarized as:
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
I. Lateral intrusion of seawater into an aquifer adjacent to the sea;
II. Downwards seepage from a saline surface waterway that overlies an aquifer;
III. Upconing of deep saline seawater that is present within an aquifer;
IV. Alteration to natural barriers between seawater and an aquifer; and
V. Increasing groundwater abstraction.
Figure 2: Movement of the saltwater interface under the increased saltwater intrusion due to
Overabstraction and sea level rise. (Abd-Elaty et al 2018)
3- Relation between climate change and sea water intrusion.
Climate is a dynamic system and is subject to natural variations at various time-scales, from years
to millennia. Like any other system, if no excitations are imposed on the climate system, the average
temperature of the globe will not change. However, the concentration of active greenhouse gases,
mainly carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4), has increased considerably
during this century. Greenhouse gases allow solar radiation to pass through the atmosphere and hit the
surface of the earth, but they intercept and store the infrared radiation emitted from the surface of the
earth (Sherif, 1995). This phenomenon warms up the atmosphere and leads to what is perceived as
global warming which is considered to be the cause of climate change. When a significant change in
climate variables from one period to another occurs, it is referred to as climate change. On the other
hand, climate variability is defined as the variation from year to year and generally occurs as a result of
natural and/or man-made activities. Thus, global warming and climate change are intertwined. Were
there no greenhouse gases in the atmosphere, the average temperature of the earth would be 30oC
cooler. Likewise, any increase in the concentration of greenhouse gases will be associated with a
corresponding increase in the average global temperature. Measurements show that the average
temperature of the earth has risen by 0.5-0.7oC since the beginning of the twentieth century. The global
temperature increase due to increasing concentrations of greenhouse gases in the atmosphere is
estimated to be 0.13 degree per decade (IPCC, 7002) and is expected to have a full range of
temperature projection of 1.1 degree to 4.6degrees by the end of this century. The range of temperature
rise is expected to lead to melting of polar caps and expansion of water in deep oceans with a
corresponding increase in the sea level. It is estimated, that a sea level rise between 18 and 88 cm will
occur by the end of this century (IPCC, 2007).
Sea level rise (SLR) has many effects on coastal regions on the long term such as increase in
coastal erosion and sea water intrusion. As a result of SLR the freshwater-saltwater interface is moving
inland causing salinization of the land and groundwater resources (Fig. 2). Salinization of groundwater
is considered a special category of pollution that threatens groundwater resources, because mixing a
small quantity (3%) of saltwater with groundwater makes freshwater unsuitable and can result in
abandonment of freshwater supply (Sherif and Singh, 2002).
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
4- Groundwater salinization and monitoring techniques
Groundwater salinization is one of the most difficult problems threatening the sustainable
groundwater resources particularly in coastal semi-arid and arid regions. In numerous coastal aquifers
across the world, the over-exploitation of groundwater has led not only to the degradation of water
quality but also to the decline of water table.
Based on the characteristics of the stresses and the hydrogeological circumstances, various types
of salinization are possible (Fig. 3): up-coning under abstraction well, salt water intrusion in
groundwater system, up-coning under low-lying areas, seepage, salt water intrusion in the surface
water (Sanchez et al., 2013), etc..
Figure 3: Examples of different types of salinization in ground water and surface water. (Sanchez et al.
2015)
- Monitoring techniques for groundwater salinity:
A number of technologies are available to monitor groundwater salinity, each of them useful
depending on the objective of the monitoring exercise. In the following paragraphs the most relevant
monitoring techniques are described:
I- Vertical Electrical Sounding (VES): A vertical electrical sounding (VES) measurement can be
performed to obtain a layer model, where each layer has its own specific resistivity. First, the
resistivity is measured with a small current electrode distance. Upon an increase of the current
electrodes, the bulk of the current will be distributed over a larger (vertical) extent. Different electrode
configurations exist, but the most appropriate and most generally applied one is the Schlumberger
configuration (Fig. 4).
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
Figure 4: Set up of a VES measurement at the beach. Four reels of wire are used to connect the
measurement unit (the orange device) to the current and potential electrodes. (Sanchez et al. 2015)
II-TEC-probe: A TEC-probe (Temperature - Electrical Conductivity) is suitable for manual 1-D
measurements of temperature and electrical conductivity (ECsoil) of soft soils like peat and clayey soils
(Fig. 5). The electrodes and temperature sensor are located at the far end of the probe. The probe has a
diameter of 22 mm and the electrode distance is 50 mm.
Figure 5: The TEC probe in the field and example of a 2D profile with TEC probe measurements.
(Sanchez et al. 2015)
III-Electric cone penetration tests (ECPT): With a ECPT, a cone is pushed at a controlled rate into the
subsurface using a heavy truck. The site should therefore allow heavy truck access. The resistance to
penetration (pressure) at the tip of the cone and the friction on a surface sleeve above the cone gives
information about the soil properties (clay or sand). With an ECPT, also the electrical resistance of the
subsurface can be determined using electrodes.
IV-Groundwater sampling: To exactly know the chloride concentration of groundwater, groundwater
samples can be analyzed precisely in the lab. This requires new or existing observation wells (Fig. 6).
For groundwater analyses at different depths so-called minifilters can be used. Automated
measurements with EC Divers are also often used nowadays.
Figure 6: Examples of groundwater sampling. (Sanchez et al. 2015)
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
V-EM-Slimflex: The EM-Slimflex is an electromagnetic induction logging tool that was developed by
Deltares in cooperation with Antares and Login (Fig. 7). The EM-Slimflex enables monitoring of the
fresh to salt water transition zone in a cost efficient way. Due to its small width (2 cm) and high
flexibility it is able to overcome deviations of the monitoring well.
Figure 7: The EM-Slimflex device. (Sanchez et al. 2015)
VI-Continuous Vertical Electrical Sounding (CVES): In a CVES measurement, a 2D technique,
multiple electrodes are used which are connected by multicore cables to a microprocessor. The
electrodes can serve as current or potential electrodes. With this microprocessor and appropriate
software, numerous electrode combinations can be used to calculate the apparent resistivity of the
subsurface. Inversion software is used to obtain a two-dimensional image of the apparent resistivity of
the subsurface.
VII-The GEONICS EM 31: The EM 31 instrument is operated by one person (Fig. 8). The instrument
consists of an extendable tube having a transmitting and a receiving coil at an inner distance of 3.6 m.
The effective exploration depth is about 6 m. The instrument is used for a quick investigation of the
lateral variability of the subsurface bulk conductivity.
Figure 8: EM 31 instrument in an agricultural field and Some results. (Sanchez et al. 2015)
VIII- Airborne geophysics: Airborne Electromagnetic (AEM) geophysical techniques can be used to
determine the resistance of the substrate in the ground, visualize a combination of geology and
groundwater salinity together (Fig. 9). In a short time, an image can be formed for entire region.
Advantages of this technique are the fast collection of data and 3D result of the resistance of the
substrate, and (with the aid of accurate 3D geologic model) a freshwater-saltwater distribution of the
groundwater.
IX- Water Quality Field Kit: The Water Quality Field Kit is a kit containing various cost-effective
monitoring techniques to measure different parameters such as electrical conductivity of water (EC),
pH, nitrate, coliform bacteria, nitrate and bicarbonate (Fig. 10).
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
Figure 9: Helicopter-borne frequency-domain electromagnetic (HEM) systems use a towed installation
with small transmitter and receiver coils (about 50 cm). (Sanchez et al. 2015)
Figure 10: Water quality monitoring kit. (Sanchez et al. 2015)
X- The smart phone application to measure salinity (SWAPP:) The SWAPP is a free App that can be
used to measure the electrical conductivity (EC) of water (Fig. 11). Based on this information the user
can decide on the usability of water. The sensor used to measure the electrical conductivity can be
hand made by the user; just little knowledge on electronics is needed. With this sensor, the user can
measure the EC of water. The combination of the sensor and the App makes it a highly cost-effective
monitoring device for measuring EC.
Figure 11: SWAPP concept: a low-cost, portable, social, predictive, yet scientifically sound method for
indicating water salinity (and thus for optimising agriculture a saline environments). (Sanchez et al. 2015)
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
XI- Electrical Resistivity Tomography (ERT): ERT is a geophysical technique in which DC electrical
current is injected into the ground between one pair of electrodes and the voltage is measured between
another pair (Fig. 12). A line (array) of electrodes is used and an instrument called a terrameter acts as
a switch box and a measuring device, sending energy to different sets of electrodes through a set
sequence. Underground resistivity can be recorded and the salinity can be concluded. It’s possible to
create a 3D image using parallel survey lines.
(a) (b)
Figure 12: Electrical Resistivity Tomography (ERT) (a) The line (array) of the electrodes, (b) The
terrameter instrument. (Lewkowicz et al. 2016)
XII- Time Domain Electromagnetic Method (TDEM): TDEM is a geophysical exploration technique
in which electric and magnetic fields are induced by transient pulses of electric current and the
subsequent decay response measured (Fig. 13). TDEM methods are generally able to determine
subsurface electrical properties, but are also sensitive to subsurface magnetic properties. TDEM
surveys are a very common surface EM technique for mineral exploration, groundwater exploration,
and for environmental mapping, used throughout the world in both onshore and offshore applications.
Figure 13: Helicopter Conducting TDEM Survey. (Lewkowicz et al. 2016)
5- Previous studies dealing with sea water intrusion in coastal regions worldwide.
Sea water intrusion is one of the most wide-spread and important processes that degrades water-
quality by raising salinity to levels exceeding acceptable drinking and irrigation water standards, and
endangers future exploitation of coastal aquifers. This problem is intensified due to population growth,
and the fact that about 70% of the world population occupies coastal plains. Human activities (e.g.,
water exploitation, including industry and agriculture, reuse of waste water) result in accelerating
water development and salinization. The explanation of the dynamic nature of the fresh-saline water
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
transition zone is of both scientific and practical interest because it reflects or controls the extent of
development or exploitation.
The source of salinity in coastal aquifers has been a subject of many studies, but in many cases is
still unclear. Seawater encroachment inland is the most commonly observed reason for the increase in
salinity, but other sources or processes can cause an increase. Custodio (1997) listed several saline
sources that can affect water quality in coastal aquifers, but which are not directly related to seawater
violation. In addition, agriculture return flows and leakage of urban sewer systems can contribute salts
to coastal aquifers. For example, Izbicki (1991) found that high levels of chloride in groundwater from
the Oxnard Plain near Los Angeles in California were derived beneath irrigation return flow
characterized by high B/CI and I/CI ratios, and not from modern seawater intrusion. Monitoring and
early detection of the origin of the salinity are crucial for water management and successful
remediation. Yet the variety of the possible salinization sources, particularly in coastal aquifers that are
sensitive to anthropogenic contamination, makes this task difficult.
In coastal aquifers a natural equilibrium exists between discharging fresh groundwater and
seawater. It is known as the sea/saltwater-freshwater interface. The position of the saline interface is
dynamic and depends on the geological formation, hydraulic gradient, topography, and the quantity of
freshwater moving through the aquifer system (Schwartz and Zhang, 2003).
The movement of fresh water can be reduced by either a reduction in groundwater recharge, or an
increase in abstraction which lead to reduction in fresh water hydraulic gradient. This can cause the
saline interface to move landwards resulting in saline intrusion and a reduction in water quality. The
chloride concentration indicative of saline intruded groundwater is 300 mg/l. As seawater has a
chloride concentration of approximately 19,000 mg/l, very little seawater is sufficient to contaminant
freshwater (McDonald et al., 1998).
Because water in aquifers is located deep underground, it is less vulnerable to pollution. As the
population growth and agricultural development in coastal areas have increased, the demand for
freshwater has increased. As a result of this demand more stress is being placed on coastal aquifers.
Saltwater intrusion is arguably the most common contamination problem in aquifers, and a major
constraint imposed on groundwater utilization (Bear et al., 1999). Saline contamination of freshwater
resources can cause significant social, economic, and environmental costs. These problems limit the
use of groundwater and create additional problems in meeting the increasing water demand.
One of the important factors affecting the salt water intrusion is well abstraction. It is important to
quantify the effects of well abstraction on both the shallow groundwater system, and the dynamics of
the saline interface. This is necessary to protect groundwater against saline intrusion in the face of an
increased number of high volume groundwater. Locating the saline/freshwater interface and
monitoring its dynamics are essential for sustainable management of coastal groundwater systems
(Essaway, 2013). The position of the saline interface, however, is not static and is likely to be a
transitional zone of changing salinity rather than a distinct boundary. Therefore it is unlikely that
discrete measurements will detect these changes (Ingham et al., 2006).
The saline interface is influenced by a number of processes forming a complex and variable
system. The density contrast between fresh groundwater and saline water leads to mixing and
convective circulation at the saline interface. The interface is thus characterized by a zone of diffusion
as the saline water mixes with the discharging freshwater. Tidal activity can induce a fluctuating water
table changing the position of the interface. Infiltration of surface waters into the sediments can also
form a surficial mixing zone (Westbrook et al., 2005).
Among the geophysical method applied for the location and movement of saltwater intrusion, best
results were obtained by electrical methods (Al-Sayed and Al-Quady, 2007; Chitea et al., 2011). Many
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
hydrological processes can be expected to provide significant contrasts in resistivity, consequently,
Electrical Resistivity Tomography (ERT) has been adopted as a tool for new research within the
hydrology field. Previous workers have demonstrated the ability of ERT to visualize hydrological
structure within laboratory cores, and monitor fluid or contaminant migration at the field scale (Daily
et al., 1992.
The utilization of the time domain electromagnetic method (TDEM) for hydrogeological
applications has dramatically increased during the last years (Kafri et al., 1997). This methodology is
based on a step-wise current flowing in a transmitting loop that produces a transient secondary
electromagnetic field in the underground. This, in turn, induces a change in voltage on a receiver coil.
The interpretation of the shape of the decay curve, related to the underground resistivity distribution,
allows us to obtain 1D resistivity models. The uncertainty of the estimation of the shallower layer parameters
can be reduced by an a priori constraint derived from geological and hydro-geological information and other
geophysical data. In this regard, combined application of D.C. and electromagnetic methods (Yang et al., 1999)
has been successfully used to study coastal aquifers.
Capizzi et al. (2010) has carried out a study of the sea intrusion phenomenon in the aquifer
between the cities of Marsala and Mazara del Vallo (south-western Sicily) using geophysical
techniques (TDEM and ERT) and geochemical analysis of well water. The aim of the research was to
optimize the acquisition techniques, data processing and data interpretation for the geometry
reconstruction of aquifers, their characterization, and the determination of concentration of pollutants.
The analysis of the geophysical results reveals the existence of very low resistivity values in
correspondence of the area from the coastline to a kilometer inland. Obviously, in this area, the sea
intrusion is more pronounced.
Javadi et al. (2013) presented a new method for optimal control of seawater intrusion. The
proposed method is based on a combination of abstraction of saline water near shoreline and recharge
of aquifer using surface ponds. The source of water for the surface pond could be treated waste water
or excess of desalinated brackish water (if any), etc. The variable density flow and solute transport
model, SUTRA, is integrated with a Genetic Algorithm optimization tool in order to investigate the
effectiveness of different scenarios of the seawater intrusion control in an unconfined costal aquifer.
The locations of the pond and the abstraction well in relation to the shoreline, depth of abstraction well
and the rates of abstraction and recharge are considered as the main decision variables of the
optimization model, which aims to minimize the costs of construction and operation of the abstraction
wells and recharge ponds as well as the salt concentrations in the aquifer. Comparison is made
between the results of the proposed method and other methods of seawater intrusion control. The
results indicate that the proposed method is efficient in controlling seawater intrusion. This proposed
strategy can be considered as a powerful tool for cost-effective management of seawater intrusion in
coastal aquifers.
Tarallo et al. (2014) conducted a 3D ERT experiment obtained in the coastal alluvial plain of the
Volturno river to assess changes in the freshwater-brine interface. The main aim was to investigate
spatial and temporal variations of groundwater salinity. Acquisitions have been carried out in the
months of May and October 2013 and in May 2014 in order to understand the extent of the
phenomenon of saltwater intrusion in time and space, resulting in qualitative and quantitative analysis
of the volume of water used. The results of this study have led to a reconstruction of a three-
dimensional model of the water bodies in different previous periods (Fig. 14).
Javadi et al. (2015) presented the results of an investigation on the efficiencies of different
management scenarios for controlling saltwater intrusion using a simulation-optimization approach. A
new methodology is proposed to control SWI in coastal aquifers. The proposed method is based on a
combination of abstraction of saline water near shoreline, desalination of the abstracted water for
domestic consumption and recharge of the aquifer by deep injection of the treated wastewater to
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
ensure the sustainability of the aquifer. The efficiency of the proposed method is investigated in terms
of water quality and capital and maintenance costs in comparison with other scenarios of groundwater
management. A multi-objective genetic algorithm based evolutionary optimization model is integrated
with the numerical simulation model to search for optimal solution of each scenario of SWI control.
The main objective is to minimize both the total cost of management process and the total salinity in
aquifer. The results indicated that the proposed method is efficient in controlling SWI as it offers the
least cost and least salinity in the aquifer.
Figure 14: 3D resistivity contour plot referred to salt water (resistivity 4-15 Ωm): a) May 2013; b)
October 2013; c) May 2014. (Tarallo et al., 2014)
Priyanka and Mahesha (2015) conducted a study to investigate the parametric analysis on
saltwater intrusion in a conceptual, coastal, unconfined aquifer considering wide range of freshwater
draft and anticipated sea level rise. The saltwater intrusion under various circumstances is simulated
through parametric studies. MODFLOW, MT3DMS and SEAWAT are used to study the effect of
freshwater draft, hydraulic conductivity of the aquifer and anticipated sea level rise due to climate
change on salt water intrusion. It may be noted that increase in recharge rate considered in the study
does not have much influence on saltwater intrusion. Effect of freshwater draft at locations beyond half
of the width of the aquifer considered has marginal effect and hence can be considered as safe zone for
freshwater withdrawals. Due to the climate change effect, the anticipated rise in sea level of 0.88 m
over a century is considered in the investigation. This causes increase in salinity intrusion by about
25%. The combined effect of sea level rise and freshwater draft considered indicated significant
increase in saltwater intrusion into coastal aquifers up to 57%.
Sanchez et al. (2015) conducted a project, SWIBANGLA – Managing salt water intrusion impacts
in Bangladesh, which is carried out by Deltares, UNESCD-IHE, and the Jahangirnagar University
under the IRG/BRAG-WASH program. In this project, the focus is on salt water intrusion in coastal
groundwater systems in the south-western coastal area of Bangladesh, as groundwater is the main
resource of drinking water in this area. The coastal region of Bangladesh covers about 20% of total
land area and over 30% of the cultivable lands of the country. A total of about 40 million people are
living in the coastal area. About 53 % of the coastal areas were affected by salinity. Since the 1960’s,
groundwater has been used extensively as the main source of drinking and irrigation water supply.
About 75% of cultivated land is irrigated by groundwater and the remaining 25% by surface water
(Zahid and Ahmed, 2006). Of the abstracted groundwater about 70-90% is used for agricultural
purposes and the rest for drinking and other water supplies. Groundwater is the main source of potable
water for nearly 98% of the population in Bangladesh.
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
The project SWIBANLGA has main objectives:
I. Create a better understanding of the process of salinization of drinking water resources in
Bangladesh.
II. Provide recommendations for monitoring.
III. Provide recommendations for adaptation to salinization and mitigation of salt water impacts.
IV. Achieve an effective knowledge transfer between the Netherlands and Bangladesh on how to
cope with salinization issues.
V. Advise on the integration of the salinization issue in Water Safety Planning (WSP).
Also, the project SWIBANLGA stated that a national groundwater salinity monitoring network can be
developed with the following steps:
I. Build capacity of the national organization for groundwater monitoring.
II. Reconcile objectives of groundwater salinity monitoring by different organizations.
III. Combine and optimize network design.
IV. Unify monitoring parameters and sampling frequency.
V. Standardize use of monitoring instruments.
VI. Develop a national database.
VII. Disseminate groundwater salinity information.
Strategies to secure safe drinking water supply in the coastal areas are proposed. These strategies
are listed as : I - Strategy for sustainability; II - Strategy for systematic monitoring; III - Strategy for
deep well injection; IV - Strategy for GO-FRESH and V - Strategy for conjunctive use.
6- Sea water intrusion problem in Nile Delta, Egypt
6.1- Introduction
Egypt lies between latitudes 22o and 32o North, and longitudes 25o and 35o East. The North
boundary of Egypt is the Mediterranean Sea, and to the East is the Red sea. The South and West are
political boundaries with Sudan and Libya, respectively. The total area of Egypt is equal to about one
million km2, about 94% of which are desert. It is located in the arid and semiarid region, where the
limited availability of renewable freshwater is the main challenge in future agriculture and urban
development. The main water resource in Egypt is the River Nile; Nile water alone is no longer
sufficient for the increasing water requirements for the different developmental activities in Egypt due
to a rapid increase in population and expected impacts of climate change especially on the agriculture
sector. The role of groundwater is steadily increasing especially in the newly reclaimed areas along the
desert fringes of the Nile Delta and Valley. Abstraction from groundwater in Egypt is dynamic in
nature as it grows rapidly with the expansion of irrigation activities, industrialization and urbanization.
Egypt's coastal zones constitute particularly important regions economically, industrially, and socially.
The Mediterranean shoreline is most vulnerable to SLR due to its relatively low elevation. This in turn
will directly affect the agricultural productivity and human settlements in coastal zones especially in
Nile Delta Zone (El-Raey, 2009). The Nile delta regions in Egypt as well as many coastal sites in the
Gulf countries and North Africa are found to be highly vulnerable. The vulnerability is not only due to
direct inundation of large areas due to SLR but also due to salt water intrusion and its potential impact
on groundwater resources and soil salinization.
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
6.2- Nile Delta Coastal Aquifer
The Nile Delta is formed in Northern Egypt where the Nile River spreads out and reaches the
Mediterranean Sea. It is one of the world’s largest river deltas, extending from 30oE to 32o30\E and
from 30oN to 31o36\16.2\\N (Fig. 15). It covers some 240 km along the Mediterranean coastline and
extends to a maximum of 160 km from north to south. The coastal area of the Nile Delta is one of the
most populated regions in Egypt. The area is commonly flat, sloping northward and eastward with
altitudes varying between 0.5 m close to El-Manzala Lake in the north and +17 m in the south,
(RIGW, 1992a). The geomorphic features of the Nile Delta region comprise the following units: The
young alluvial (fluviatile) plains; the old alluvial (fluviatile) plains; Fanglomerates; Sand dunes; and
Turtle backs, as shown in Fig. 16.
Figure 15: The Nile delta Aquifer. (Sherif and Al-Rashed, 2001)
Figure 16: Geomorphological map for the Nile Delta region. (Nofal, 2015)
The Nile Delta region lies within the temperature zone, which is a part of the great Desert belt.
The average temperatures in January and July at Cairo are 12oC and 31oC, respectively. Minimum and
maximum temperatures at Cairo are 3oC and 48oC, respectively. Rainfall over the Nile Delta is rare
and occurs in winter. Maximum average rainfall along the Mediterranean Sea shore, where most of the
rain occurs, is about 180 mm. This amount decreases very rapidly inland to about 26 mm at Cairo.
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
However, the Delta, as the case with the northernmost part of Egypt, is characterized by relatively
moderate temperatures, with highs usually not exceeding 31oC in the summer.
The ground elevation ranges between about 18 m above mean sea level (AMSL) in the south at
Qanater El-Khairia to about 5 m (AMSL) near Tanta sloping down very gently in a northward
direction by an average value of 1 m/10 Km (Saleh, 1980). Furthermore, the Nile Delta slopes from
east to west making the Damietta branch 2 meters higher than the Rosetta branch (Al-Agha et al.,
2015).
Agriculture activities are predominant in the region (around 63% of the total agricultural land) due
to the nature of the soil (Dawoud, 2004) and an irrigation system in place. The main constraint of
future agriculture is the limited availability of renewable freshwater. Nile River is the main water
resource; it is no longer sufficient for the increasing water requirements for the different
developmental activities, so the role of groundwater is steadily increasing and is expected to cover
about 20% of the total water supply in the upcoming decades especially in the newly reclaimed areas
along the desert fringes of the Nile Delta and Valley (Dawoud et al., 2005).
The Nile Delta aquifer is among the largest underground freshwater reservoirs in the world. The
hydrogeologic investigation of the Nile Delta aquifer revealed the existence of well-defined hydraulic
boundaries that delimit the aquifer geometry. As shown in Fig. 15, the aquifer is bounded by the
Mediterranean Sea in the north and the Suez Canal in the east. Ismailia Canal in the southeast is
considered as the limiting boundary of the aquifer, while in the west and southwest, Wadi El-Natrun
fault represents another distinct boundary of the aquifer (Sherif and Al-Rashed, 2001). In the vertical
dimension, the Nile Delta aquifer has variable thicknesses as shown in Fig. 17.
Figure 17: Cross-section in middle Delta. (Sherif and Al-Rashed, 2001)
There are six groundwater aquifers in Egypt, and the Nile aquifer represents 87% of the total
groundwater pumping in Egypt. However, the groundwater aquifer of the Nile Delta is not considered
as an additional or separate water resource from the Nile because it is directly connected to its river
channels. Aquifers generally are refilled by effective rainfall, lakes and rivers. This water may reach
aquifers rapidly via macro-pores or fissures or slowly through soil infiltration and permeable rocks.
The direct seepage of Nile water from drainage and irrigation systems and, moreover, irrigated and
cultivated lands are the main sources of Nile Delta aquifer recharge (Sefelnasr and Sherif, 2013; Abd-
Elhamid et al., 2016).
The quality of the groundwater in this area may be strongly affected by the impact of the sea level
rise combined with changes of Nile River flows, leading to an increase in the salinity levels of
groundwater. In addition, the current and future human activities, especially extensive and unplanned
groundwater abstraction, are resulting in deterioration of the available groundwater resources. Serious
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
negative socioeconomic impacts can follow as a consequence. In the Nile Delta, extensive
groundwater abstraction is also a very significant factor that increases seawater intrusion. Groundwater
wells which were beyond salinization zones in the past are consequently showing upconing of saline or
brackish water (Mahmoud, 2017).
The bulk of the Nile Delta aquifer consists of deltaic deposits 300-400 m thick on average. Shata
and Hefny (1995) indicated that in the Delta area, as well as its fringes, the strata of hydrological
importance belong essentially to the Quaternary and to the Tertiary (Fig.18). Of these strata, the deltaic
deposits (200-500 m thick) that belong to the Pleistocene constitute the bulk of the main aquifer. These
are dominated by unconsolidated coarse sands and gravel, with occasional clay lenses. The top
boundary of the deltaic deposits, which acts as a cap for the aquifer, is composed of semi-pervious clay
and silt layers, which varies in thickness and disappears in some places. In such places, the aquifer is
considered to be phreatic since its free water surface is subjected to atmospheric pressure. The thin
clay layer varies from 5 m in the south to 20 m in the middle and reaches 50 m in the North of the Nile
Delta (Fig. 17). The clay cap is intermeshing with the aquifer near the shore (Fig. 17, Fig. 19). The
saturated thickness of the aquifer varies from 200 m in the southern parts to about 1000 m in the
northern parts (RIGW, 1992a). Fig.20 presents the contour lines of the aquifer thickness(Sherif, 1999).
The depth to the groundwater table in the Nile Delta ranges between 1–2 m in the North, 3–4 m in
the Middle and 5 m in the South (Mabrouk et al., 2013). The depth to water decreases towards Rosetta
branch to range between 2.5 m and 5 m. Thus, the flow of groundwater movement is from southeast to
Northwest towards Rosetta branch in the central part of the Nile Delta (Al-Agha et al., 2015). A
regional contour map of the depth to groundwater and the piezometeric contour map in Nile delta
region in 2008 were drawn based on recent field observations (Fig. 21 and Fig. 22). Areas with very
shallow groundwater include the region between Damanhur and Lake Edku and the saline depressions
south of Lake Manzala, and near Ismailia.
Figure 18: Quaternary Aquifer (Lower Aquifer) Map. (RIGW, 1992a)
Figure 19: Clay Layer Thickness (Upper Aquifer) Map. (Saleh, 2009)
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
Figure 20: Contour lines for the aquifer thickness. (Sherif, 1999)
6.3- Groundwater Aquifer System in the Nile Delta Region
On the basis of geomorphology, the hydrogeological features of the Nile Delta region are divided
into three major regions which are the floodplain (area of 9,126 km2), the eastern Nile Delta fringes
(area of 10,220 km2), and the western Nile Delta fringes (area of 11,042 km2). There are different
groundwater aquifers with different importance for exploitation in the Nile Delta region. These
aquifers are the semi-confined Quaternary aquifer, phreatic sandy aquifer, Pliocene aquifer, Moghra
aquifer, and sand dune aquifer as shown in Fig. 23.
Figure 21: Depth to groundwater of the Nile Delta region in 2008. (Al-Agha et al., 2015)
Figure 22: Piezometric head of the Nile Delta region in 2008. (Al-Agha et al., 2015)
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
Figure 23: Configuration of aquifer systems in the Nile Delta region. (Sakr, 2005)
The Moghra aquifer is located in the Western Delta region. It has an area of about 50,000 km2.
The aquifer consists of Lower Miocene sand and gravel. The aquifer is found in the west of Wadi El-
Natrun and extends toward the Qattara Depression. The aquifer is phreatic south of latitude 30oN but
confined by Pliocene deposits in the northern direction. Oligocene rocks (basalts or shales) underlie the
Moghra aquifer. The base of the Moghra aquifer slopes from ground level near Cairo to 100 m below
sea level near Borg El Arab area. The saturated thickness ranges from 70 to 700 m (RIGW/IWACO,
1990). The groundwater flow in the Moghra aquifer is directed westward, toward the Qattara
Depression. Inter-aquifer flow is a minor component of recharge, which occurs from the Nile Delta
toward the Moghra and Pliocene aquifers. The groundwater salinity is good to brackish with a
maximum value of 7,000 ppm. The salinity values increase from very low in Wadi El-Farigh to high in
the north and western part. West of Wadi El-Natrun, the groundwater quality is brackish. The
potentiality of Moghra aquifer varies between low and moderate according to the Research Institute for
Groundwater (RIGW) (Sakr, 2005). The outflow of the Nile Delta aquifer also occurs toward the
Moghra aquifer along the fringes of the western Nile Delta, with a transfer estimated by
RIGW/IWACO (1990) between 50 and 100 Mm3/year.
The Pliocene aquifer is present in Wadi El-Natrun depression. The aquifer is considered a local
low productive aquifer. It is a multilayered aquifer consisting of an alternation of sand and clayey
layers belonging to the Pliocene age. The aquifer is underlain by the Moghra aquifer but separated
from it by layers of lower Pliocene age. In this area, the groundwater is discharged through a great
number of seepage zones into small lakes and ponds. Groundwater is lost by direct evaporation with an
annual rate of 70 million cubic meters according to RIGW (1998) (Sakr, 2005).
The most important regional aquifer in the Nile Delta is the Quaternary aquifer. This aquifer
consists of Pleistocene graded sand and gravel, changing to fine and clayey facies in the north. The
aquifer is found along the entire Nile Delta floodplain. The clay cap of the Nile aquifer is a semi-
confining layer and has a thickness up to 20 m. The Nile Delta aquifer is underlain by Pliocene marine
clay in the Central Delta and wedges out toward the fringes (Negm et al., 2018).
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
6.4- Assessment of Groundwater Quality in the Nile Delta
Extensive urban, agricultural and industrial expansions on the Nile Delta of Egypt have exerted
much load on the water needs and lead to groundwater quality deterioration. Documenting the spatial
variation of the groundwater quality and their controlling factors is vital to ensure sustainable water
management and safe use. A comprehensive dataset of 451 shallow groundwater samples were
collected in 2011 and 2012 (Masoud A.A. 2014). On-site field measurements of the total dissolved
solids (TDS), electric conductivity (EC), pH, temperature, as well as lab-based ionic composition of
the major and trace components were performed. Groundwater types were derived and the suitability
for irrigation use was evaluated.
Most hydrochemical parameters showed very wide ranges; TDS (201–24,400 mg/l), pH (6.72–
8.65), Na+ (28.30–7774 mg/l), and Cl− (7–12,186 mg/l) suggesting complex hydrochemical processes
of multiple sources. TDS violated the limit (1200 mg/l) of the Egyptian standards for drinking water
quality in many localities. Extreme concentrations of Fe2+, Mn2+, Zn2+, Cu2+, Ni2+, are mostly related to
their natural content in the water-bearing sediments and/or to contamination from industrial leakage.
Very high nitrate concentrations exceeding the permissible limit (50 mg/l) were potentially maximized
toward hydrologic discharge zones and related to wastewater leakage.
Three main water types; NaCl (29%), Na2SO4 (26%), and NaHCO3 (20%), formed 75% of the
groundwater dominated in the saline depressions, sloping sides of the coastal ridges of the depressions,
and in the cultivated/newly reclaimed lands intensely covered by irrigation canals, respectively. Water
suitability for irrigation use clarified that the majority of the groundwater samples (83%) had very high
to high salinity hazards. These are unsuitable for irrigation of regular crops and hence special
management practices with salt resistant plants were recommended.
Zeidan B. A. (2017) collected groundwater samples from the quaternary aquifer from selected
wells on the basis of geographical distribution. Most of the selected wells are used for irrigation and
domestic uses and their depths range from 13 to 60 m. Other samples may also be collected from the
drain and canals waters as given in Fig. 24. All the water samples were collected for chemical and
isotope analyses. Electrical conductivity (EC), bicarbonate, dissolved oxygen (DO), temperature, and
pH measurements were measured in situ.
Figure 24: Location map of surface and groundwater samples. (Ghoraba 2009)
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
The salinity map drawn from a representative set of 34 groundwater samples is shown in Fig. 25.
Total dissolved solids show large spatial variations between 320 and 6112 mg/L, while dissolved
oxygen (DO) ranges between 0.85 and 4.89 mg/L with a mean value of 2.21 mg/L.
Figure 25: Areal distribution of total dissolved solids (TDS) in mg/L for groundwater samples. (Ghoraba
2009)
The groundwater in the Nile Delta is quite vulnerable to pollution; deterioration of groundwater
indicates clearly that the human activities caused serious pollution problems in addition to seawater
intrusion. The nitrate concentrations have clear mount within the Nile Delta ammonium concentrations
of groundwater reached an alarming level and exceeded the drinking water standards (0.5 mg/L). The
potential sources of nitrogen compound pollution are: water from sewage treatment plant used for
irrigation, sludge and animal manure, septic tanks, soil nitrogen, and artificial fertilizers. Most of the
contaminant flows towards the northern-west direction. The hydraulic properties and gradient play the
major role on the contaminant transport direction.
6.4.1- Remediation of Contaminated Groundwater in Nile Delta
Remediation schemes may employ dewatering systems through selected extraction wells to pump
the contaminated groundwater out of the aquifer for treatment. The locations of wells should be chosen
towards the flow direction of contaminant. Dynamic groundwater quality monitoring network in the
Nile Delta is highly recommended to cope with increasing pollution concentrations.
On-site sanitation systems can be designed in such a way that groundwater pollution from these
sanitation systems is prevented from occurring. Detailed guidelines have been developed to estimate
safe distances to protect groundwater sources from pollution from on-site sanitation.
Portable water purification devices or “point-of-use” (POU) water treatment systems and field
water disinfection techniques can be used to remove some forms of groundwater pollution prior to
drinking, namely any fecal pollution. Many commercial portable water purification systems or
chemical additives are available which can remove pathogens, chlorine, bad taste, odors, and heavy
metals like lead and mercury. Techniques include boiling, filtration, activated charcoal absorption,
chemical disinfection, ultraviolet purification, ozone water disinfection, solar water disinfection, solar
distillation, and homemade water filters.
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
6.5- Groundwater Salinity in Nile Delta due to Sea Water Intrusion
It is worth to mention that before 1996, there was not any monitoring system for seawater
intrusion except for some shallow wells to monitor the top portion of the aquifer. The collected data
from such shallow wells indicated that the salinity distribution in the Quaternary aquifer is very
complicated to describe and raised a lot of concerns (Zeidan, 2017). The existing drainage and
irrigation systems, the return flow from irrigation, the dissolution of the salt in the clay layer
overlaying the aquifer, and the historical geologic evolution have direct impact on the salinity
distribution (RIGW, 2011). FAO, 2009 has produced groundwater salinity contour maps for the years
1960 through 2000. These maps concluded that the groundwater salinity in the Nile Delta aquifer has
been affected by the development activities. Groundwater salinity increased after the year 1980 and the
iso-salinity line of 1000 ppm moved southward indicating more saline water intrusion as shown in map
of the year 1990 as shown in Fig. 26.
Figure 26: Distribution of groundwater salinity in Nile Delta. (FAO, 2009)
The Nile Delta aquifer salinity increases northward, reflecting the effect of sea water on
groundwater. The sea water wedge was described suggesting that sea water intrusion is about 30 km
far from shoreline, whereas the points of interface is at distance of 80 km far from shoreline. The Nile
Delta aquifer is classified into three hydro-chemical zones. The southern zone is characterized by fresh
to brackish water of carbonate type and continental origin. The coastal zone is characterized by fresh to
brackish water of chloride-bicarbonate water type and mixed continental and marine origin. The
northern zone is characterized by saline to highly saline water of marine origin (Saleh, 1980).
6.6- Soil Salinization of the Nile delta due to Sea Water Intrusion
Salt-affected soils, in spite of their scattered occurrence, mainly exist in the northern part of the
Nile Delta. In the Mediterranean coastal plains and lower Delta, excessive rates of groundwater
withdrawal has resulted in a large drop in the water table and, as a consequence, seawater intruded into
the aquifers (GARE, 1992). The main reasons for soil salinity in these areas include seawater intrusion,
irrigation with low quality (saline) water as they are located at the downstream regions of the system,
and an inadequate field drainage. Fig. 27 gives a classification of salt-affected soils in the Nile Delta.
Basically, soil salinity problems related to irrigation with low quality (saline) water occur when salts
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
accumulate in the crop-root zone and, consequently, the available water in soil for the crop is reduced.
Another possibility, where a shallow groundwater table exists and as a result of upward movement of
water-containing salts, evapotranspiration leads to a salt accumulation in the top soil. This type of
secondary soil salinization is mainly attributed to poor drainage conditions. Once, proper drainage is
installed and the groundwater table is stabilized at deeper depths, either the salinity problem would be
controlled, or recognized as a problem of the first type, i.e. the applied irrigation water is too saline.
Fig. 28 indicates the range of drainage rates in the Nile Delta.
Figure 27: Categorization of the salt-affected soils in the Nile Delta. (El-Gunidy, 1989)
Figure 28: Drainage rates in the Nile Delta in mm/day during 1992/1993. (DRI, 1994)
As seas rise many areas of the coasts will be submerged, with increasingly severe and frequent
storms and wave damage, shoreline retreat will be accelerated, in addition to expected disastrous
flooding events caused by severe climate events such as heavy flooding, high tides, windstorms in
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
combination with higher seas. It is noted that Egypt is considered one of the top five countries
expected to be mostly impacted with a 1.0 m SLR in the world (Dasgupta, et al., 2007).
The general conclusion is that, apart from a few and small catchments in the Middle and South
Delta, the majority of the areas with high drainage rates (5.22±10.68 mm/day) lies along the coastal
plain. These areas are considered the last sites for water recycling before the final disposal into the
Mediterranean Sea and Terminal Lakes. The average drainage rate in Egypt is assumed to be 1
mm/day for the design of subsurface drainage system according to the above-mentioned conditions
(Abdel-Aziz, 1997). Normally, the assumed drainage rate is adequate for properly operating systems as
in the case of the South Delta. In contrast, the high drainage rates in the North Delta cause an
inadequate drainage system and result in high water tables. Moreover, the North Delta catchments may
become water-logged by the intruding sea water.
6.7- Effect of sea level rise (SLR) on Nile Delta coastal area
Egypt’s population would be most severely impacted by SLR (Fig. 29). With a 1m SLR,
approximately 10% of the Egypt’s population would be impacted. Most of this impact takes place in
the Nile Delta; it reaches 20% with a 5m SLR. Egypt’s GDP would also be significantly impacted by
SLR. This is partly explained by the impact of SLR on the Egypt’s agricultural extent. Indeed, most of
the impact of SLR on the agricultural sector of the region would take place in Egypt which would
experience a severe impact (Fig. 30). Even with a 1m SLR, approximately 12.5% of the Egypt’s
agricultural extent would be impacted; this percentage reaches 35% with a 5m SLR. The Egypt’s
agricultural sector may thus experience severe disruption as a result of SLR (Dasgupta, et al., 2007).
Several general analyses of the potential impact of SLR on the Nile delta coast have been carried
out. The high risk areas include parts of Alexandria and Beheira governorates, Port Said and Damietta
governorates, and Suez governorate. The sea level rise in three coastal cities, Alexandria, Port Said and
Suez, using five different statistical models: linear, quadratic, logarithmic, exponential and power
models, was investigated by Alam El Din and Abdel Rahmin (2009). They concluded that the sea level
rise was not uniform in the three cities. In Alexandria, the annual rate ranged between 1.94 and
2.22mm/yr, in Port Said, it was between 2.7 and 3.6 mm/yr. In Suez on the Red Sea, it ranged between
0.90 and 1.9 mm/yr. They reported that sea level rise is expected to accelerate as a function of time.
Figure 29: Middle East and North Africa region: population impacted. (Dasgupta, et al., 2007)
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
Figure 30: Middle East and North Africa region: Agricultural extent impacted. (Dasgupta, et al., 2007)
El Fishawi (1993) predicted that a 49 cm sea level rise by the year 2050 is likely to cause
salinization in the river mouth of 500–800 mg/L. El-Raey et al. (1997, 1999) studied the economic and
social impact that could be induced due to seawater intrusion. They found that the sea level rise will
lead to the loss of a large area of touristic villages and harbors that have great economic value to
Egypt, and even more than agriculture.
6.8- Effect of Ground water abstraction from Nile Delta Aquifer on Salinity
Groundwater abstraction is a major cause of sea water intrusion in coastal aquifers. Increasing
water abstraction from coastal aquifers lead to decreasing the movement of freshwater to the sea and
accordingly, increasing seawater intrusion inland. In the Nile Delta, extensive groundwater abstraction
is a very significant factor that increases seawater intrusion. Groundwater wells which were beyond
salinization zones in the past are consequently showing up-coning of saline or brackish water.
Increased abstraction leads to reduced freshwater head, which allows progression of the seawater
further in land. In Egypt extensive unplanned abstraction causes the deterioration of the Quaternary
aquifer, especially in the northern coast. Historical records show a continuous increase in the
abstraction rates over the last 30 years (during the period of 1980–2010), which is summarized in Fig.
31. It can be noticed that it increases linearly by about 0.10X109 m3 per year, except from the period of
2003 till 2010 where the abstraction increases dramatically by the rate of 0.20X109 m3 per year
(Mabrouk et al., 2013).
The salinity of groundwater is changing with changing water levels of the canals based on
analyzing the historical records. After 1984, the groundwater salinity started to increase due to
extensive abstraction and reduction in the flow of the Nile. When the Nile water flow increased in
1990, the salinity of groundwater reduced again to its former levels. However, in 2000, the salinity of
groundwater increased again due to extensive abstraction and new reclamation projects (Sakr et al.,
2004).
Figure 31: Abstraction rates versus time in Nile Delta. (RIGW, 1980, 1992b, 2003, and 2010, Mabrouk et
al., 2013)
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
6.9- Water and Salt Balance in Nile Delta Aquifer
The water influx to the Nile Delta aquifer includes the seepage from the Nile river and its two
main branches, seepage from the extensive irrigation and drainage networks, infiltration of the excess
of the irrigation water, recharge from rainfall events, and the possible replenishment from the Nile
Valley aquifer in the southern part. Saline water also intrudes the aquifer from the lower part of the
northern, seaside, boundary and rotates back to the Mediterranean sea as mixed (brackish) water
through the upper part of the sea boundary. The aquifer may also receive lateral influx from the eastern
and western boundaries. The out flux includes pumping of significant amounts of groundwater,
evaporation losses and the flow of the brackish water to the Mediterranean sea (Sherif et al. 2012).
In the southern parts of the aquifer the water table is higher than the aquifer piezometric head,
considerable amounts of freshwater can percolate downward to the groundwater. In the northern parts,
the aquifer piezometric head is higher than the free water table, hence the groundwater moves upward
through the clay cap. This water in the clay cap, either evaporates or finds its way to the drainage
system. The aquifer is also intruded through its open boundaries at the Mediterranean Sea with saline
water. Due to its greater density seawater migrates into the aquifer. A one cubic meter of seawater
contains about 35 kilograms of salts (Sherif, 2003).
The out flux of salts in the Nile Delta aquifer is encountered through:
I- the water flowing back to the sea due to the rotational character of flow at the sea side
boundary.
II- the upward flux of groundwater to the upper semi-pervious layer due to the difference between
the aquifer piezometric head and the free water table in the clay cap. Salts will either transport
with water to the drainage system or accumulate in the clay cap.
III- the water pumped from production wells. Generally small amounts of salts could be lost from
the system through pumping activities. The pumped water is mostly fresh.
IV- the water flowing out of the system through lateral boundaries.
Like all transport processes in groundwater systems, the movement of the equiconcentration lines
is very slow. Unless considered over a relatively long period, the movement of the equiconcentration
lines may not be recognized. Under normal conditions, the direction of the groundwater flow is
generally toward the Mediterranean Sea. Over-pumping may lead to a reverse seawater flux to the land
side and the intrusion process might be accelerated (Sherif et al. 2012).
The location of the interface/transition zone may vary over time depending on the distribution of
the pressure heads within the system, recharge and discharge events, and other human activities. It
should be noted that the movement of the seawater may not be consistent along the entire width of the
Nile Delta. For example, if the water levels in the two main branches (Rosetta and Damietta) of the
Nile are relatively high, the seawater wedge may retard in the vicinity of the Nile braches but not along
the entire width of the Delta. On the other hand, excessive pumping from well fields may cause local
inland seawater intrusion (Sherif et al. 2012).
6.10- Sea water intrusion in Nile Delta Aquifer
The case of the Nile Delta aquifer is unique. It is one of the largest groundwater reservoirs in the
world with a huge volume and storage capacity. It has a wide (245 km) and a deep (more than 900 m)
exposure to the Mediterranean sea. It is perhaps the only coastal aquifer in which the seawater has
migrated to a distance of more than 100 km from the shore boundary. Fig. 32 provides a schematic
presentation of the seawater intrusion problem a vertical section in the middle Delta.
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
Figure 32: A schematic presentation of a cross section in the middle Nile Delta aquifer. (Sherif et al.
2012)
Saltwater intrusion problem will cause increase in the soil salinity, as a result will cause decrease
in the land productivity and socioeconomics, migration of people due to health complications. Under
conditions of climate change, the sea water levels will rise. The rise in sea water levels will impose
additional saline water heads at the sea side and therefore more sea water intrusion is anticipated. A 50
cm rise in the Mediterranean Sea level will cause additional intrusion of 9.0 km in the Nile Delta
aquifer, also the aquifer is more endangered under the conditions of climate change and sea level rise.
Additional pumping will cause serious environmental effects in the case of the Nile Delta aquifer
(Sherif, 1999).
Many studies were conducted to simulate the seawater intrusion in the Nile Delta aquifer using
various numerical techniques. Most of which were based on the sharp interface approach, while few
accounted for the dispersion zone and density variation. Based on the numerical simulations,
equiconcentration and equipotential lines were drawn to characterize the flow pattern and salinity
distribution in the horizontal and vertical cross-section of the Delta aquifer. Field investigations and
experiences revealed the existence of a considerable dispersion zone between the aquifer freshwater
and the intruded seawater. The sharp interface assumption is therefore not justified in such an aquifer
(Sherif and Al-Rashed, 2001).
Gaame (2000) used the SUTRA model code to simulate the behavior of the transition zone of Nile
Delta under different abstraction intensities. He declared that the northern part of the Middle Delta is
more salinized than the southern part. The model tested the impact of pumping freshwater and brackish
water simultaneously which is known as the scavenger well scheme. He concluded that a unique saline
well could be used in order to control a number of four or more fresh water pumping wells at a certain
distance (circle of influence) to maintain the transition zone at its equilibrium position.
El-Didy and Darwish (2001) studied seawater intrusion in the Nile Delta aquifer under the effect
of fresh water storage in the northern lakes of Manzala and Burullus. The system was simulated using
SUTRA model and a Lake model called LAKE. They concluded that the storage of freshwater in the
lakes El-Burullus and El- Manzala can minimize the intrusion around them.
Sherif and Al-Rashed (2001) presented various simulation scenarios for the seawater intrusion
problem in the Nile Delta aquifer. Two models, 2D-FED and SUTRA, are used to simulate the
problem in the vertical and horizontal sections, respectively. The 2D-FED model is employed to
simulate the current conditions and predict the effect of the water level rise in the Mediterranean sea
under the condition of global warming.
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
To investigate the seawater intrusion under the condition of climate change three scenarios were
considered. In all scenarios, the shoreline was maintained at its current location. The effect of the
submergence of low lands by seawater was not considered. The Salinity distribution under the different
scenarios were then compared with those under the current conditions (Fig. 33).
Figure 33: Vertical simulation in the Delta aquifer, Equiconcentration lines. (Sherif and Al-Rashed, 2001)
In Scenario-1, all hydraulic and transport parameters were kept constant. The water level in the
Mediterranean was raised by 0.2 m, while the free water table was kept unchanged. Initial vertical
equipotential lines were assumed. Like the solute concentration, the piezometric head is not known a
prior; it is adjusted through the iterations according to water mass balance of the system. Under this
condition, equiconcentration line 35.0 kg/m3 (35,000 ppm) advanced slightly while equiconcentration
line 5.0 advanced by a distance of 2.0 km, measured along the bottom boundary. Equiconcentration
line 1.0 advanced inland by a distance of 2.5 km, as shown in Fig. 34a.
In Scenario-2, the seawater level was raised by 0.5 m and all other parameters were kept to their
basic values. Equiconcentration line 35.0 migrated inland by 1.5 km as compared to the current
conditions, while equiconcentration line 5.0 moved inland by a distance of 4.5 km measured along the
bottom boundary as shown in Fig. 34b. Equiconcentration line 1.0 advanced inland by a distance of
about 9.0 km. Low equiconcentartion lines were more affected by the sea level rise than the higher
ones.
In Scenario-3 the effect of the additional pumping from the Nile Delta aquifer was investigated
and the piezometric head on the land side was lowered by 0.5 m (as a result of additional pumping and
other parameters were kept unchanged. Under this scenario, equiconcentration line 35.0 advanced
inland to a distance of 6.0 km (compared to the current conditions) measured along the bottom
boundary. Equiconcentration line 5.0 intruded by a distance of 11.5 km, measured along the same
boundary. The width of the dispersion zone increased considerably, as shown in Fig. 34c. Any
additional pumping from the Nile Delta aquifer will cause a significant increase in the seawater
intrusion. The effect of additional pumping is more significant than the effect of sea level rise.
To examine the effect of pumping on seawater intrusion and define the best locations for
additional pumping, six different scenarios were selected (Sherif and Al-Rashed, 2001). The
simulation was performed using SUTRA and the results were compared in the areal view. The area of
the Nile Delta was divided into three main zones for pumping activities; the middle zone, the eastern
zone, and the western zone, as shown in Fig. 35. They concluded that any additional pumping should
be practiced in the middle Delta and pumping from the eastern and western parts should be reduced.
They confirmed that redistribution of pumping may help mitigate the intrusion migration.
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
Figure 34: Effect of sea level rise and additional pumping: Equiconcentration lines under (a)
Scenario-1, (b) Scenario-2, and (c) Scenario-(3). (Sherif and Al-Rashed, 2001)
Figure 35: Zones of pumping in the Nile Delta. (Sherif and Al-Rashed, 2001)
To investigate the effect of land use on the sea-water intrusion problem additional scenarios for
rice cultivation in the northern and southern parts of the Nile Delta were considered (Sherif, 2003)..
First, an area of 1 million fed. of rice cultivation was considered in the northern part of the Delta with
an average rate of water application of 8800 m3/fed. Second, the same area of rice cultivation was
moved to the southern part of the Delta assuming the same rate of water application. Evaporation and
evapotranspiration were evaluated and the remaining water was assumed to recharge the groundwater
system. Equiconcentration lines were presented for the two cases. In this exercise, the current pumping
activities were maintained and the simulation was conducted under the transient conditions to assess
the possible changes in the water quality due to the different scenarios of rice cultivation.
Results indicated that rice cultivation in the southern part of the Delta would contribute effectively
to the mitigation of the seawater intrusion. The clay layer in the southern Delta is not only more
permeable but also thinner. This will allow the excess irrigation water to percolate deep into the
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
aquifer and recharge the groundwater system. Cultivation of rice in the southern Delta would maintain
a steep hydraulic gradient toward the seaside.
It was also noted that reducing areas of rice cultivation and/or reducing rates of water application
in the north would help mitigate the seawater intrusion. The effect of different scenarios of rice
cultivation in the north would be momentous after several years. The average rate of the displacement
of the equiconcentration lines is in the order of 50 m/year.
An approach to study seawater intrusion problems in the Nile Delta aquifer in Egypt is presented
by Sherif et al. (2012). FEFLOW, a 3D finite element variable density model, is employed, however,
because of the lack of 3D data, and to demonstrate the proposed approach, the simulations are
performed in 2D horizontal views. After calibration against field observations, the simulations are
conducted at four horizontal sections located at different levels (100, 200, 300 and 400 m) below the
mean seawater level. The study domain is modified for the horizontal sections at 300 and 400 m,
respectively, to account for the aquifer geometry at these depths. The effect of freshwater recharge
from the Nile River on the seawater intrusion is observed in the upper layer around its two main
branches. The results of the horizontal simulations clearly demonstrate the variation of water
concentration in the vertical direction. In the middle Delta and at the mean seawater level, the model
results matches the observed results confirming the fact that the seawater intruded inland to a distance
of about 40 km, followed by a 30 km transition zone. As the depth increases, the transition zone (in
which the concentration varies from the seawater to the freshwater concentration) is shifted toward the
landside and become more extensive. At the lower levels of the Nile Delta aquifer, the seawater
migrates much further inland as compared to the shallower levels. The concept of horizontal
simulations at different levels is further developed to produce meaningful concentration distributions
in the vertical sections (Fig. 36). This approach allows for a better realization of seawater intrusion in
coastal aquifers.
Figure 36: Seawater intrusion in the vertical sections interpolated from the horizontal simulations. Sherif
et al. (2012)
Essaway (2013) developed a three-dimensional groundwater model for the whole Nile Delta
region and the density-driven flow problem associated with seawater intrusion which is solved using
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
the well-established Groundwater Modeling System (GMS) package that includes the MODFLOW,
MT3d and SEAWAT. The saltwater/freshwater interface locations in Nile Delta aquifer was
invesigated under the effect of sea level rise (three scenarios 0.2, 0.5, and 1 m) after 50 and 100 years
(Fig. 37). It is found that the range of expected sea level rise (0.2 – 1.0 m) leads to the migration of
saltwater-freshwater interface for an additional 1.0 to 4.5 km 50 years after the rise occurs and between
2.0 and 6.0 km 100 years after the rise. In general, It is concluded that the effect of sea level rise on the
saltwater intrusion in the Nile Delta aquifer does not seem to be significant.
Figure 37: The distance from the shoreline to the saltwater/freshwater showing the effect of the scenarios
on the long run. (Essaway, 2013)
Also, the average width of the transition zone for each SLR scenario was investigated (Essaway,
2013). Here, the transition zone is defined by the zone with salinity varying between 1,000 ppm and
35,000 ppm. Outside this zone there is either freshwater with salinity below 1,000 ppm or saltwater
with seawater salinity. Fig. 38 indicates the width of the transition zone does not change with the
amount of SLR. This is because the increase in sea water level pushes both interfaces of the transition
zone inland with more or less the same advancing distance leading to the same transition zone width.
The transition zones appears to grow with time where in 50 years the width of the transition zone will
be about 21 km, in 100 years it will be about 22 km and in 500 years the average width of the
transition zone will be about 24 km.
Figure 38: Width of the transition zone in the Nile Delta after 50, 100 and 500 years. (Essaway, 2013)
Sefelnasr and Sherif (2014) studied possible effects of seawater level rise in the Mediterranean
Sea accompanied with different rates of well abstraction on the seawater intrusion problem in the Nile
Delta Aquifer using FEFLOW. Six different scenarios were considered. Scenarios one, two, and three
assumed a 0.5 m seawater rise while the total pumping is reduced by 50%, maintained as per the
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
current conditions and doubled, respectively. Scenarios four, five, and six assumed a 1.0 m seawater
rise and the total pumping is changed as in the first three scenarios. They concluded that, large areas in
the coastal zone of the Nile Delta will be submerged by seawater and the coast line will shift landward
by several kilometers in the eastern and western sides of the Delta. Scenario six (sea water rise is 1.0 m
and the current rate of pumping is doubled) represents the worst case under which the volume of
freshwater will be reduced to about 513 km3 (billion m3).
Abdelaty et al. (2014) used a 3-D model (SEAWAT) to study seawater intrusion in Nile delta
aquifer considering different scenarios, the first scenario is the increase of sea level by 25, 50 and 100
cm, the second is to decrease the surface water system by 25, 50 and 100 cm, the third is to increase
the extraction rate by 25, 50 and 100 % and fourth scenario is a combination of while the three
scenarios. The results show that saltwater intrusion in East Nile delta reach 76.25 km from shore line
for base case, but reaches to 79.25 km, 79 km, 82 km and 83 km for Equiconcentration line 35 and
reaches to 92.25 km, 92 km, 91.75 km and 92.75 km for scenarios1, 2, 3 and 4 respectively after 100
year for Equiconcentration line 1.00. It is also observed that salt water intrusion in the Middle reaches
to 63.75 km from shore line for base case, but reaches to 67.75 km, 67.25 km, 65.75 km and 67.50 km
for Equiconcentration line 35 and reaches to 97 km, 97.50 km, 107.75 km and 110 km for scenarios1,
2, 3 and 4 respectively after 100 year for Equiconcentration line 1.00. It is clear that saltwater intrusion
in the West reaches to 48.00 km from shore line for base case, but reaches to 49.00 km, 48.75 km,
45.50 km and 47.75 km for Equiconcentration line 35 and reaches to 73.75 km, 74 km, 79.50 km and
79.50 km for scenarios1, 2, 3 and 4 respectively after 100 year for Equiconcentration line 1.00. Finally
increasing SLR or decreasing recharge from surface water or increasing extraction rate from wells
increases saltwater intrusion in land direction but applying combination of these scenarios will damage
large quantity of fresh water in the aquifer as shown in Fig. 39.
Figure 39: Areal Distribution of TDS for Combination of Three Scenarios Change by (a) 25 %, (b) 50 %
and (c) 100 %. (Abdelaty et al., 2014)
Abd-Elhamid et al. (2016) presented a coupled transient finite element model for simulation of
fluid flow and solute transport in saturated and unsaturated soils (2D-FEST) and employed to study
seawater intrusion in the Nile Delta aquifer. The developed model was used to investigate the problem
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
considering the possible impacts of climate change. The results were compared with SEAWAT code,
and good agreement was obtained. Figures 40, 41 and 42 show areal view of groundwater levels in
Nile Delta aquifer; horizontal and vertical distributions of TDS in Nile Delta aquifer were considered.
Three scenarios were studied, rise in sea level, a decline of the piezometric head at the land side due to
excessive pumping and the combination of sea level rise and decline of the piezometric head at the
land side. The results showed 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.
Figure 40: Areal view of groundwater levels in Nile Delta aquifer. (Abd-Elhamid et al., 2016)
Figure 41: Horizontal distribution of TDS in Nile Delta aquifer. (Abd-Elhamid et al., 2016)
Figure 42: Vertical distribution of TDS in Nile Delta aquifer. (Abd-Elhamid et al., 2016)
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
Tarabees and El-Qady 2016 conducted a research focused on the detection of sea water intrusion
in Rashid area which is located about 75 km east to Alexandria, Egypt. For this purpose, geoelectrical
survey was carried out using the Schlumberger Vertical Electric Sounding (VES) to identify freshwater
thickness, sea water intrusion and estimate subsurface lithology. Seventeen VES stations were
measured with current electrode separation (AB/2) ranging from 1.5 m to 100 m. Then, the VES data
was interpreted using 1-D and 2-D inversion schemes of DC resistivity data based on least squares
method with smoothness constrains. The inverted resistivity distribution at relatively shallow depth
shows an important low resistivity zone that probably reflects salt water alteration zone (northern
parts). Depth to the freshwater bearing layer reaches its maximum at the south and decreases towards
the north. From quantitative interpretation, invasion of salt water started at depth about 10 m at north
in the thickness of freshwater bearing layer ranging from 15 to 25 m, while at depth of about 120 m all
the layers were saturated with salt water.
Engelen et al. 20018 conducted computational analyses to assess possible origins of hypersaline
groundwater which it is three times more saline than sea water at 600 m depth using both analytical
solutions and numerical models (Fig. 43). It is concluded that the hypersaline groundwater can either
originate from Quaternary free convection systems, or from compaction-induced upward salt transport
of hypersaline groundwater that formed during the Messinian salinity crisis. The results also indicated
that with groundwater dating it is possible to discriminate between these two hypotheses. Furthermore,
it is deduced that the hydrological connection between aquifer and sea is crucial to the hydrogeological
functioning of the Nile Delta Aquifer.
Figure 43: (a): Total Dissolved Solids (TDS) measurements at 400 and 600 m depth in the Nile Delta and
head difference (Dh0) over the anhydrite layer, expressed in freshwater head (b): Sketched conceptual
geological cross-section of the Nile Delta. (Engelen et al. 20018)
6.11- Mitigations and adaptations suggested for the salt water intrusion problem in
Nile Delta Aquifer
Different measurement to control seawater intrusion and to protect the groundwater resources
have been considered in past studies. The main principle is to prevent saltwater from contaminating
groundwater sources, and to increase the volume of fresh groundwater and reduce the volume of
saltwater (Essaway, 2013). Some studies included measures such as:
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
I - Relocation of abstraction wells by moving the wells further inland and practice any additional
pumping in the middle Delta (Sherif and Al-Rashed, 2001). This method can be an effective
measure in the Nile Delta.
II - Naturally recharging the aquifer with additional surface water (Ru et al., 2001). This method
may helps pushing the saltwater front towards the sea. As we explained earlier, since the clay
layer in the southern Delta is not only more permeable but also thinner, moving rice cultivation
to the southern part of the Delta would contribute effectively to the mitigation of the seawater
intrusion. This will allow the excess irrigation water to percolate deep into the aquifer and
recharge the groundwater system. Reducing areas of rice cultivation and/or reducing rates of
water application in the north would help mitigate the seawater intrusion (Sherif, M. 2003).
III - Abstraction of saline water to reduce the volume of saltwater by extracting brackish water
from the aquifer (Sherif and Hamza, 2001). As explained later, the extracted brackish water can
be used to mitigate pollution in northern polluted lakes.
IV - Reduction of abstraction rates by reducing pumping rates and using alternative water
resources (Scholze et al., 2002). However, it may not be recommended in Egypt since the
country suffers from limited water resources compared with the dramatically increase in rate of
population. However, it could be replaced by controlling the excessive abstractions and
establishment of pumping regulations (Mabrouk et al. 2013).
V - Combining freshwater injection and saline water abstraction systems to reduce the volume of
saltwater and increase the volume of freshwater (Rastogi et al., 2004). Another approach is to
implement a system of Abstraction, Desalination and Recharge (ADR), consisting of three
steps;
a) Abstraction of brackish water from the saltwater zone.
b) Desalination of the abstracted brackish water using reverse osmosis (RO) treatment process.
c) Recharge of the treated water into the aquifer.
This method aims to reduce the volume of saltwater and to increase the volume of fresh water.
This method is usually repeated till dynamic equilibrium is reached. However, it is difficult to
be implemented in Egypt due to its high cost.
VI - Artificially recharging the aquifer to increase the groundwater levels, using surface spread for
unconfined aquifers and recharge wells for confined aquifers. The sources of water for injection
may be surface water, groundwater, treated wastewater or desalinated water (Papadopoulou et
al., 2005). Rainwater can also be used effectively in recharging the Nile Delta aquifer
especially in the area exposed to high runoff due to intensive rains (Alexandria and El Beheira
Governorates).
Another measure, that was also considered, deals with using subsurface barriers to prevent the
inflow of seawater into the groundwater basin (Harne et al., 2006). But due to its high cost it may be
not recommended. However, Shore protection works will be necessary to reduce land immersion by
sea water and protect shore line from erosion.
In case of the Nile Delta, existing studies were predominantly focused on adaptation measures.
Very few existing studies have discussed mitigation measures related to groundwater salinization.
Mitigation measures were more studied in relation to the erosion of the coastal strip of Nile Delta,
which is another problem that can increase in the future due to sea level rise and more severe weather
events. Table 1 summarizes a number of adaptation and mitigation measures proposed by different
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
researchers and their advantages and disadvantages. Generally those studies were dealing with
salinization of groundwater on different deltas around the world (Mabrouk et al., 2013).
Table (1) Different adaptation and mitigation measures for groundwater salinization in Deltas
worldwide (Mabrouk et al., 2013)
Measure
Advantages
Disadvantages
Conclusion
a) Adabtation
1 - Rice cultivation (El
gunidy et al. 1987;
Kotb et al., 2000)
Soil salinization patterns
decrease considerably.
Needs a large amount of
water which is already a
scarce resource
Not recommended as it is
uneconomic.
2 - Permitting 10 to 20 %
of the fresh water of
irrigation to leach the
soil (Abrol et al. 1988)
No salt accumulation, salt
export will match salt
import and will eventually
prevent salt infiltration to
groundwater.
This could be risky
because it might cause
salt returning to the root
zone again.
Not recommended.
3 - Cultivating salt
tolerant crops (Fao,
1985)
Tolerant crops can
withstand salt concentration
in the north.
Very limited types of
plants.
Highly recommended.
4 - Creating wetlands in
salinized areas (IPCC,
2008)
Egypt has four lakes in the
northern coast of the Nile
Delta which could be
considered as natural
adaptation.
Only applicable in low
lying deltas of the Nile
Delta.
Highly recommended in
Egypt.
5 - Extraction of saline
groundwater (Oude
Essink, 2001)
Getting rid of saline water.
Disposal of extracted
saline water could cause
another environmental
problem.
Not recommended for
shallow coastal aquifers.
6 - Increasing land
reclamation (Oude
Essink, 2001)
Increase freshwater
recharge.
Need of land and
freshwater.
It is recommended.
b) Mitigation measures
1 - Artificial recharge
(Bray and Yah, 2008;
Richard and Johnson,
2005; Luyen et al.
2011; Carrera, 2010)
Increase freshwater outlow
to the aquifer. The degree of
efficiency of this method
depends on
pumping/injection rates,
depth of the wells, the
coastal aquifer properties
and the location of the wells.
Needs a large amount of
water which is already a
scarce resource
It is recommended in case of
water abundance as it is
highly effective method.
Most of the work that has been carried out in the above proposed adaptive measures is directed
towards a specific location in the Nile Delta. The disadvantage of this is that the proposed adaptation
plan could negatively influence another region of the Nile Delta. Unfortunately most of the proposed
adaptation and/or mitigation measures in Nile Delta stop at the phase of recommendation. A
comprehensive strategy for adaptation schemes that is proposed as a result of model-based analysis
and evaluation is missing. Also, the effect of integrating two or three adaptation methods together has
not been studied. Model-based analysis of such combinations may indicate a possible way forward. In
addition, strong institutional capabilities to implement some of the proposed alternatives could be a
huge constraint in Egypt, as is the case in many developing countries.
The study concluded that expansion in rice cultivation is uneconomic because of the large amount
of water needed but it is suggested that the ministry of agriculture move some rice cultivated areas
towards areas of salinization problems to solve the problem without changing the total required water.
Cultivating salt tolerant crops and creating wetlands in salinized areas in low lying areas are very
suitable in Egypt. Although the study shows that the extraction of saline ground water is not
recommended in Egypt because the disposal of the saline water could cause another problem but the
idea can be used in areas of low land near the northern lakes and the disposal can go to the lakes. This
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
will bring two advantages, decrease the piezometric head of the salt water (drawback of the saline
interface towards the sea) and enhance the environmental situation in the lakes which suffer from high
rate of pollution due to direct and indirect waste disposal.
7- Discussion
Sea water intrusion is considered a major risk for coastal regions, in particular coastal aquifers.
The phenomenon causes salinization to a great area of the coastal regions especially the delta regions.
Delta areas in many countries all over the world especially in developing countries are considered the
backbone of the country’s economy. A great percentage of the agricultural lands are located there.
Besides, in general coastal areas are of a great environmental, economic, social and cultural relevance.
Consequently, saltwater intrusion in coastal regions was the subject of many comprehensive studies all
over the worlds for the past 30 years. However, these studies and their methodologies depend mainly
on the characteristics of each area they investigated. Mitigation and adaptation concluded from these
studies may not necessary be applicable in other regions suffer from the same problems. For example,
some mitigations are very costly (i.e. deep barriers at the shore line in order to prevent salt intrusion,
treatment of extracted brackish water by RO in order to be reused for the recharge) which some
developing/poor countries could not afford.
Many factors affect the saltwater intrusion problem; climate change, groundwater recharge and
wells abstraction are the most important ones. The saline interface will move landwards causing a
reduction of water quality due to:1- A decrease in groundwater recharge or/and an increase in
abstraction which lead to reduction in fresh water hydraulic gradient, 2-Sea level rise or sea water
flooding which lead to increase in saltwater hydraulic gradient and immersion of coastal lands.
Egypt is considered one of the top five countries expected to be mostly impacted with a 1.0 m sea
level rise (SLR) in the world. However, past research proved that the effect of SLR alone is not
significant concerning saltwater intrusion problem. The effect will be magnified if the SLR will be
accompanied with immersion of coastal land and/or extensive well extraction and/or reduction in
groundwater recharge. SLR will cause large areas in the coastal zone of the Nile Delta to be
submerged by seawater and the coast line will shift landward by several kilometers in the eastern and
western sides of the Delta. SLR of 1.0 m with doubled the current rate of pumping will cause the
reduction of volume of freshwater by 513 km3 (billion m3) (Sefelnasr and Sherif 2013). Therefore, the
implementation of a suitable standardize monitoring system for the saltwater intrusion by monitoring
groundwater salinity and locating the saline/freshwater interface and monitoring its dynamics are
essential for sustainable management of coastal groundwater systems and to seek protection actions.
There are many technologies available to monitor groundwater salinity and the saline/freshwater
interface location, each of them useful depending on the objective of the monitoring (see sec. (3)).
However, Unify monitoring parameters and sampling frequency and standardize use of monitoring
instruments are crucial for data collection accuracy. Many studies used electrical methods (Electrical
Resistivity Tomography (ERT) and time domain electromagnetic method (TDEM)) successfully to
determine the location and movement of saltwater intrusion.
Although electrical methods or chemical analyses are good tools to detect salinity in given
conditions, they are insufficient for forecasting future salinity conditions. Saltwater intrusion analysis
through the aquifer with all the hydrological dimensions is very complicated, and should be based on
prediction of future conditions that can be provided by groundwater modeling accompanied with
continuous monitoring.
Various numerical techniques were used to assess and simulate the seawater intrusion all over the
world. There are many types of models that can be used successfully in prediction of saltwater
intrusion phenomenon (i.e. FEFLOW, SUTRA, SEAWAT, 2D-FED, AQUIFEM1). Among of these
models, one of the most popular codes in recent years has been SEAWAT, which uses the concept of
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
equivalent fresh water head for simulating density dependent flows, where the flow calculations are
performed by the popular MODFLOW code and MT3D used for the solute transport. This code has
shown very good results in seawater intrusion modeling studies in several different applications
outside and inside Egypt. Consequently, SEAWAT may be a good candidate code for developing the
kind of integrated three-dimensional model of the Nile delta aquifer.
Few studies have used 3-D models, previous studies concerning saltwater intrusion and
groundwater salinity modeling in Nile Delta were mainly carried out using 2-D vertical (cross
sectional) or 2-D horizontal models. The problem with using 2-D vertical models is that the
representative cross sections should be selected carefully and that results are not transferable to other
areas of the delta. Besides, researchers used 2D model on vertical or horizontal section through Nile
Delta aquifer studied the dispersivity in one direction and ignored it in the other direction. So their
model results may not be accurate enough. Another problem, that some of these studies used the sharp
interface approach. The fact that the transition zone between salt and fresh water in this aquifer is
quite large required using the variable density approach. Furthermore, most of these studies were local
in nature. Some researchers attempt to study the whole delta region by using 2-D models in the
horizontal directions or vertical 2-D models for selected cross section. Unfortunately, these approaches
cannot visualize the full dynamics of the freshwater/seawater interaction in three dimension directions.
In fact, the fully 3-D models are rarely developed for the whole Nile Delta aquifer due to their
complexity, data needs and long computational time. However, future research should clearly be
oriented towards development of a fully 3-D variable density model of the Nile Delta aquifer that can
serve as a predictive tool for analyzing future mitigation and adaptation measures.
Many studies proposed different mitigation and adaptation measures for the problem of saltwater
intrusion and groundwater salinization. The main principle is to prevent saltwater from contaminating
groundwater sources, and to increase the volume of fresh groundwater and reduce the volume of
saltwater. Some of these measures could be implemented in Egypt. Others, due to its high cost, will be
difficult to implement. From previous studies and private suggestions, adaptation and mitigations
measures that can be implemented in the Nile Delta could be;
I- Relocation of abstraction wells by moving the wells more inland, practice any additional
pumping from the middle of the Nile Delta and reduce pumping from the eastern and western
parts,
II- Controlling the excessive abstractions and establishment of pumping regulations by
optimization of well pumping rates in order to meet irrigation/drinking water demand and to
prevent salt water intrusion,
III- Cultivation salt tolerant crops (barley, sugar beet, wheat, cotton) in area of high soil salinity in
the north,
IV- Moving crops needs large amount of water like rice to the area south of the Delta,
V- Extraction of saline water to feed north lakes to enhance their environmental pollution and to
get rid of the saline water,
VI- Artificial recharge of the aquifer by using rainwater harvesting or treated wastewater,
VII- Shore protection works to reduce land immersion by sea water.
It should be taken into consideration the complete economic and environmental feasibility
objectives for a whole set of measures and these results could then be presented to decision makers.
However, the proposed measures are studied individually and only focusing in a certain region rather
than covering the whole Nile Delta. Besides, the effects of integrating two or more
adaptation/mitigation methods together have not been studied. The disadvantage of this is that the
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
proposed measures plan could negatively influence another region of the Nile Delta. Consequently, the
adaptation and mitigation measures need to be analyzed within an integrated regional plan
accompanied with effective monitoring, evaluation and assessment system.
8- Conclusions
In this research work the following conclusions were obtained:
1 - Sea water intrusion phenomenon is considered the most hazardous problem affecting coastal
regions in particular coastal aquifers specially in Nile Delta aquifer.
2 - The phenomenon causes salinization to a great area of the Nile Delta coastal regions.
3 - Many factors affect the saltwater intrusion problem; climate change, groundwater recharge and
wells abstraction in the Delta regions are the most influential ones.
4- The implementation of suitable monitoring for the saltwater intrusion by monitoring
groundwater salinity and locating the saline/freshwater interface and monitoring its dynamics are
essential for sustainable management of the Delta coastal groundwater systems and to seek protection
actions.
5 - Unify monitoring parameters and sampling frequency and standardize use of monitoring
instruments under a national integrated project are essential for data collection accuracy and for
development of a national reliable database.
6 - Groundwater monitoring networks from different agencies should be integrated into a national
groundwater monitoring network.
7- Egypt is considered one of the top five countries expected to be mostly impacted with a 1.0 m
sea level rise (SLR) in the world.
8 - However, past research proved that the effect of SLR alone is not significant concerning
saltwater intrusion problem. The effect will be magnified if the SLR will be accompanied with
immersion of coastal land and/or extensive well extraction and/or reduction in groundwater recharge
9 - Among the mitigation and adaptation measures used to control seawater intrusion the
following measures are the most applicable in Nile Delta aquifer:
I- Well abstraction management by controlling its rate and the excessive abstractions and
relocation of abstraction wells by moving the wells further inland and practice any additional
pumping from the middle Delta only with reduction pumping from the eastern and western part
(Numerical groundwater models should be used to optimize well locations, distance between
wells, depth of wells and pumping rates);
II- Cultivation of salt tolerant crops in area of high soil salinity in the north of Delta;
III- Relocating of Rice cultivation to area south of the Delta;
IV- Extraction of saline water to feed north lakes to enhance their environmental pollution and to
get rid of the saline water;
V- Using rainwater harvesting or treated wastewater to recharge the aquifer; and
VI- Shore protection works to reduce land immersion by seawater and protect shore line from
erosion.
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
9 - Recommendations
The following are recommendations for future researches:
1 - It is recommended that future research should clearly be oriented towards development of a
fully 3-D variable density model of the Nile Delta aquifer that can serve as a predictive tool for
analyzing future mitigation and adaptation measures. The effect of integrating two or more
adaptation/mitigation methods together should be studied.
2 - Another challenge facing the Nile Delta aquifer is the fact that the aquifer is mainly recharged
by the infiltration from irrigation network and excess of irrigation water. Due to the conflict between
Egypt and the Nile basin’s countries (i.e., Ethiopia), Egypt’s share of the Nile water may probably be
decreased in the near future. This will have a great effect on the water levels in the irrigation networks
and the aquifer total natural recharge amount. As a result, saltwater intrusion problem is expected to be
widespread due to the excessive pumping rate and the reduction of the natural aquifer recharge. So, it
is recommended to concentrate the future research mostly towards development of a new techniques to
mitigate and adapt this problem.
3 - Formulation of sustainable groundwater development plan (number of wells, well locations,
pumping rates, and operation times) is crucial in order to mitigate these effects.
4 - The effect of future Nile water reduction on saltwater intrusion problem accompanied with
other explained factors (groundwater extraction and climate change) should be studied through the
most pessimistic and optimistic prediction.
5 - Several methods are available to investigate the control of saltwater intrusion into the coastal
aquifers. These methods should be tested using the numerical simulation to decide its technical
feasibility to apply to control the saltwater intrusion to the Nile Delta aquifer.
6 - Also, a comprehensive feasibility studies should be conducted before implementing any of the
technically feasible methods.
References
Abdelaty, I.M., Abd-Elhamid, H.F., Fahmy, M.R., and Abdelaal, G.M., (2014). " Investigation of some
Potential Parameters and its Impacts on Saltwater Intrusion in Nile Delta Aquifer". Journal of
Engineering Sciences, Assiut University, Faculty of Engineering, Vol. 42, No. 4, July 2014, PP
931-955
Abd-Elaty, I.M., Abd-Elhamid, H.F., and Negm, A.M., (2018), "Investigation of Saltwater Intrusion in
Coastal Aquifers". Groundwater in the Nile Delta, Hdb Env Chem, DOI 10.1007/698_2017_190,
Springer International Publishing AG 2018
Abdel-Aziz, Y., (1997), "Land drainage for water table and salinity control", Water Resources Outlook
for the 21st Century: Conflicts and Opportunities, A Special Session on Water Management under
Scarcity Conditions: The Egyptian Experience, IXth World Water Congress of IWRA
(International Water Resources Association), Montreal, Canada. pp. 69±79.
Abd-Elhamid, H., Javadi, A., Abdelaty, I., and Sherif, M., (2016), "Simulation of seawater intrusion in
the Nile Delta aquifer under the conditions of climate change". Hydrol Res 47:1198–1210.
https://doi.org/10.2166/nh.2016.157
Al-Agha, D.A., Closas, A., and Molle, F., (2015), "Survey of groundwater use in the central part of the
Nile Delta". Water and salt management in the Nile Delta: Report No. 6, Australian Center for
International Research.
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
Alam El-Din, K.A., and Abdel Rahman, S.M., (2009). "Is the rate of sea level rise accelerating along
the Egyptian coasts", Climate Change Impact in Egypt, Adaptation and Mitigation Measures
Conference, Egyptian Research Center, Alexandria, Egypt, April, 2009.
Al-Sayed E.A., El-Quady G.; (2007). "Evaluation of sea water intrusion using the electrical resistivity
and transient electromagnetic survey: case study at Fan of Wadi Feiran, Sinai; Egypt". EGM 2007
International Workshop, Italy.
Bear, J., and Cheng, A.H.-D. (1999). Introduction. In: Bear, J., et al., (eds). "Seawater intrusion in
coastal aquifers - concepts, methods and practices". Kluwer Academic Publishers, Dordrecht, 640
pp.
Capizzi, P., Cellura, D., Cosentino, P., Fiandaca, G., Martorana, R., Messina, P., Schiavone,S. and
Valenza, M. (2010). "Integrated hydrogeochemical and geophysical surveys for a study of sea-
water Intrusion". Bollettino di Geofisica Teorica ed Applicata 12/2010; 51(4-4):285-300
Chitea F., Georgescu P., and Ioane D.; (2011). "Geophysical detection of marine intrusion in black sea
coastal areas(Romania) using VES and ERT data". Geo-Eco-Marina 17/2011, pp. 95-102.
Custodio, E., (1997). "Studying, monitoring and controlling seawater intrusion in coastal aquifers," In:
Guidelines for Study, Monitoring and Control, FAO Water Reports No. 11, 7-23.
Daily W., Ramirez A., LaBrecque D., and Nitao J.; (1992). "Electrical resistivity tomography of
vadose water movement". Water Resources Research, v.28, pp. 1429-1442.
Dawoud, A.M. (2004). "Design of national groundwater quality monitoring network in Egypt", J.
Environ. Monitor. Assess., 96, 99–118.
Dawoud M.A., Darwish M.M., and El-kady M.M. (2005). "GIS-based groundwater management
model for western Nile Delta". Water Resour Manag 19:585–604. https://doi.org/10.1007/s11269-
005-5603-z
De Louw, P.G.B., Eeman, S., Siemon, B., Voortman, B.R., Gunnink, J.L., van Baaren, E.S., and Oude
E., G.H.P., (2011). "Shallow rainwater lenses in deltaic areas with saline seepage". Hydrology and
Earth System Sciences 15, 3659–3678.
Drainage Research Institute (DRI), (1994), "Drainage water in the Nile Delta". yearbook of 1992/1993,
Reuse Monitoring Programme, National Water Research Centre, Egypt.
EGSA, (1997). Egyptian General Survey and Mining: Topographical Map cover Nile Delta, scale
1:2000000.
El-Didy, S.M., and Darwish, M.M. (2001), "Studying the effect of desalination of Manzala and
Burullus". Lakes on salt water intrusion in the Nile Delta, Water science, National Water Research
Center, 2001.
El-Fishawi, N.M., (1993). "Recent sea level changes and their implications along the Nile Delta coast",
Sea level change and their consequences for Hydrology and water Management
Noordwijkerhout,the Netherlands, UNESCO, IHP-IV Project H-2-2.PP.IV.3-11, April, 1993
El-Gunidy, S., (1989). "Quality of drainage water in the Nile Delta". In: Amer, M.H., de Ridder, N.A
(Eds.), Land Drainage in Egypt, Drainage Research Institute. pp. 189-206.
El-Raey, M., Fouda, Y., and Nasr, S., (1997). "GIS Assessment of the vulnerability of the Rosetta area,
Egypt to impacts of sea rise", J. Environ. Monitor. Assess., 47, 59–77.
El-Raey, M., Frihy, O., Nasr, S.M., and Dewidar, K.H., (1999). "Vulnerability assessment of sea level
rise over Port said governorate, Egypt", Kluwer Academic Publishers, J. Environ.
Monitor.Assess., 56, 113–128.
El-Raey, M (2009). "The Cost of Coastal Vulnerability to Climate Change". Conference on climate
change and coastal cities, beaches and the Delta, Cairo,Egypt.
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
Engelen, J.V., Gualbert, H.P., Essink, O., Kooi, H., and Bierkens, M.F.P., (2018). "On the origins of
hypersaline groundwater in the Nile Delta aquifer". Journal of Hydrology 560 (2018) 301–317.
Essaway, B. (2013). "Effect of Climate Change on Sea Water Intrusion in the Nile Delta Coastal
Aquifer". A master of science in irrigation and Hydraulics, Faculty of Engineering, Cairo
University, July.
FAO, (2009), "Rapid assessment study: towards integrated planning of irrigation and drainage in
Egypt". In: Support of the integrated irrigation improvement and management.
http://www.fao.org/3/a-a0021e/a0021e09.htm
Farid, M.S. (1985). "Management of Groundwater System in the Nile Delta", Ph.D. thesis, Faculty of
Engineering, Cairo University, Egypt.
Gaame, O. M. (2000). "The behavior of the transition zone in the Nile Delta aquifer under different
pumping schemes", Ph.D. thesis, Faculty of Engineering, Cairo University, Egypt.
Ghoraba, S.A., (2009), "Ground water quality management in the Middle Delta utilizing
environmental". isotopes. PhD. Thesis, Faculty of Engineering, Tanta University, Egypt
Government of the Arab Republic of Egypt (GARE), 1992. Environmental action plan, Egypt. pp. 5-
29.
Harne, S., Chaube, U.C., Sharma, S., Sharma, P., and Parkhya, S., (2006). "Mathematical modeling of
salt water transport and its control in groundwater". Natural and science journal, Vol. 4(4): 32-39.
Intergovernmental Panel on Climate Change (IPCC) (2007). Climate Change 2007: Synthesis Report.
Contribution of Working Groups I, II and III to the Fourth Assessment Report of the
Intergovernmental Panel on Climate Change Maskell, and C.A. Johnson (eds.). Cambridge
University Press, Cambridge, United Kingdom and New York, NY, USA, 881pp.
IPCC: (2008). "Climate Change and Water". Technical Paper of the Intergovernmental Panel on
Climate Change, edited by: Bates, B. C., Kundzewicz, Z. W., Wu, S., and Palutikof, J. P.,IPCC
Secretariat, Geneva, p. 210.
Ingham, M., McConchie, J.A., Wilson, S.R. and Cozens, N. (2006). "Measuring and monitoring
saltwater intrusion in shallow unconfined coastal aquifers using direct current resistivity
traverses". Journal of Hydrology (NZ), 45(2): 89-102.
Izbicki, J.A., (1991). "Chloride sources in a California coastal aquifer," In: Peters, H. [ed.] , Ground
Water in the Pacific Rim Countries, ASCE, Irrigation Div. Proc., 71-77.
Javadi, A.A., Hussain, M.S. and Sherif, M.M., (2013). "Optimal control of seawater intrusion in
coastal aquifers". the International Conference on Computational Mechanics (CM13),Durham
University and the UK Association of Computational Mechanics in Engineering (ACME),25-27
March 2013, At Durham,UK
Javadi, A., Hussain, M., Sherif, M., and Farmani, R., (2015). "Multi-Objective Optimization of
Different Management Scenarios to Control Seawater Intrusion in Coastal Aquifers". Water
Resources Management 29(6), April 2015.
Kafri U., Goldman M. and Lang, B.; (1997). "Detection of subsurface brines, freshwater bodies and
interface configuration in-between by the time domain electromagnetic method in the Dead Sea
Rift, Israel". Environmental Geology, 31, 42-49, doi: 10.1007/s002540050162.
Lewkowicz, A., Miceli, C., Duguay, M., and Bevington, A., (2016). "Electrical Resistivity
Tomography (ERT) as an essential tool to investigate sites in discontinuous permafrost".
Department of Geography,University of Ottawa
Mabrouk, M.B., Jonoski, A., Solomatine, D., and Uhlenbrook, S., (2013). "A review of seawater
intrusion in the Nile Delta groundwater system – the basis for assessing impacts due to climate
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
changes and water resources development". Hydrol. Earth Syst. Sci. Discuss., 10, 10873–10911,
2013
Mahmoud, M.A., (2017), "Groundwater and Agriculture in the Nile Delta". A.M. Negm (ed.),
Groundwater in the Nile Delta, Hdb Env Chem, DOI 10.1007/698_2017_94, Springer
International Publishing AG 2017
Masoud, A.A., (2014), "Groundwater quality assessment of the shallow aquifers west of the Nile Delta
(Egypt) using multivariate statistical and geostatistical techniques". Journal of African Earth
Sciences, volume 95, July 2014, Pages 123-137
McDonald, R.J., Russill, N.R.W., Miliorizos, M. and Thomas, J.W. (1998). "A geophysical
investigation of saline intrusion and geological structure beneath areas of tidal coastal wetland at
Langstone Harbour, Hampshire", UK. In: Robins, N. S. (ed.) Groundwater Pollution, Aquifer
Recharge and Vulnerability. Geological Society, London, Special Publications. 130: 77-94.
Negm, A.M., Sakr, S., Abd-Elaty, I., and Abd-Elhamid, H.F., (2018), "An Overview of Groundwater
Resources in Nile Delta Aquifer". A.M. Negm (ed.), Groundwater in the Nile Delta, Hdb Env
Chem, DOI 10.1007/698_2017_193, Springer International Publishing AG 2018
Nofal, E.R., Amer, M.A., El-Didy, S.M., and Fekry, A.M., (2016). "Delineation and modeling of
seawater intrusion into the Nile DeltaAquifer: A new perspective", Science Direct, Water Science
29 (2015),pp. 156–166
Papadopoulou, M.P., Karatzas, G.P., Koukadaki, M.A., and Trichakis, Y., (2005). "Modelling the
saltwater intrusion phenomenon in coastal aquifers – A case study in the industrial zone of
Herakleio in Crete". Global NEST journal,Vol. 7 (2): 197-203.
Priyanka,b and Mahesha, A., (2015). "Parametric Studies on Saltwater Intrusion into Coastal Aquifers
for Anticipate Sea Level Rise". Aquatic Procedia 4 ( 2015 ) 103 – 108
Rastogi, A.K., Choi, G.W., Ukarande S.K., (2004). "Diffused interface model to prevent ingress of
seawater in multilayer coastal aquifers". J. special hydrology, 4(2): 1-31.
RIGW, (1980). "Project of Safe Yield Study for groundwater Aquifers in the Nile Delta and Upper
Egypt, Part 1", Ministry of Irrig., Academy of Scientific Research and Technology, and
Organization of Atomic Energy, Egypt, 1980 (in Arabic).
RIGW, (1992a). "Hydrogeological Map for The Nile Delta area". Scale 1: 500000.
RIGW, (1992b). "Groundwater Resources and Projection of Groundwater Development", Water
Security Project, (WSP), Research Inst. for Groundwater, Kanater El-Khairia, Egypt.
RIGW, (2003). "Monitoring of groundwater microbiological activities in the Nile Delta aquifer". A
study completed for the National Water Quality and Availability Management project
(NAWQAM), Kanater El-Khairia, Egypt.
RIGW, (2010). "The Annual Technical report for year 2010", Research Inst. for Groundwater, Kanater
El-Khairia, Egypt,.
RIGW, (2011), "Adaptation to the impact of sea level rise in the Nile Delta coastal zone", Egypt. J Am
Sci 10(9)
RIGW/IWACO, (1990), "Hydrological inventory and groundwater development plan western Nile
Delta region". TN77. 01300-9-02 Research Institute for Groundwater, Kanater El-Khairia
Ru, Y, Jinno, K, Hosokawa, T, Nakagawa, K, (2001). "Study on effect of subsurface dam in coastal
seawater intrusion” 1st Int. Conf. Saltwater Intrusion and Coastal Aquifers, Monitoring,
Modelling, and Management (Morocco).
Sakr, S.A., Attia, F.A., and Millette, J.A. (2004). "Vulnerability of the Nile Delta aquifer of Egypt to
seawater intrusion". International conference on water resources of arid and semi-arid regions of
Africa. Issues and challenges, Gaborone, Botswana
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
Sakr, S.A., (2005), "Impact of the possible sea level rise on the Nile delta aquifer". A study for Lake
Nasser flood and drought control project (LNFDC/ICC), Planning Sector, Ministry of Water
Resources and Irrigation
Saleh, M.F., (1980). "Some Hydrogeological and Hydrochemical Studies on the Nile Delta". M.Sc.
Thesis, Fac. of Science, Ain Shams University.
Saleh, W., (2009). "Environmental management of groundwater resources in the Nile delta region".
PhD. Thesis, Faculty of Engineering, Cairo University.
Sanchez, F., Bashar, K., Janssen, M., Vogels,M., Snel, J., Zhou, Y., Stuurman, R., and Essink , O.,
(2015). "SWIBANGLA: Managing salt water intrusion impacts in coastal groundwater systems in
Bangladesh". A technical Report for the project SWIBANGLA No: 1207671-000-BGS-0016.
Sefelnasr, A., Sherif, M., (2014), "Impacts of Seawater Rise on Seawater Intrusion in the Nile Delta
Aquifer, Egypt", National GroundWater Association. doi: 10.1111/gwat. Vol. 52, No. 2–
Groundwater–March-April 2014 : pp. 264–276
Scholze, O, Hillmer G, Schneider, W, (2002). "Protection of the groundwater resources of Metropolis
CEBU (Philippines) in consideration of saltwater intrusion into the coastal aquifer". 17th Salt
Water Intrusion Meeting, Delft, the Netherlands.
Shata, A., and Hefny, K., (1995). "Strategies for planning and management of groundwater in the Nile
Valley and Nile Delta in Egypt". Working Paper Series No. 31-1, Strategic Research Program
(SRP), NWRC-MPWWR, Cairo.
Sherif, M.M., (1995). "Global warming and groundwater quality", in European Symposium on Water
Resources Management in the Mediterranean under Drought or Water Shortage Conditions:
Economic, Technical, Environmental and Social Issues, Nicosia, Cyprus.
Sherif M.M., (1999). "The Nile Delta Aquifer in Egypt", Chapter 17 in .Seawater Intrusion in Coastal
Aquifers: Concepts, Methods and Practices. Bear, J., Cheng, A., Sorek, S.,Ouazar, D., and
Herrera, A., (eds.)., Book Series: Theory and Application of Transport in Porous Media, Vol. 14,
pp. 559-590, Kluwer Academic Publishers, The Netherlands,1999.
Sherif, M.M., (2001). "Simulation of seawater intrusions in the Nile Delta aquifer", first international
conference on saltwater intrusion and coastal aquifers monitoring, modeling and management,
Essaouira, Morocco.
Sherif, M., (2003). "Seawater intrusion in the Nile Delta Aquifer: An Overview”. aguas.igme.es
Sherif, M., and Al-Rashed, M., (2001). "Vertical and Horizontal Simulation of Seawater Intrusion in
the Nile Delta Aquifer First International Conference on Saltwater Intrusion and Coastal
Aquifers". Monitoring, Modeling, and Management. Essaouira, Morocco.
Sherif, M.M., and Hamza K.I., (2001). "Mitigation of seawater intrusion by pumping brackish water".
J. Transport in Porous Media, 43 (1): 29-44.
Sherif, M., Sefelnasr, A., and Javadi, A., (2012). "Incorporating the concept of equivalent freshwater
head in successive horizontal simulations of seawater intrusion in the Nile Delta aquifer, Egypt”
Journal of Hydrology 464–465 (2012) 186–198.
Sherif, M.M., and Singh, V.P., (2002). Effect of groundwater pumping on seawater intrusion in coastal
aquifers. Agricultural Sciences 7 (2), 61–67.
Schwartz, F.W. and Zhang, H., (2003). "Fundamentals of Groundwater". John Wiley & Sons, New
York, United States. 592p.
Tarabees, E., and El-Qady, G., (2016). "Sea Water Intrusion Modeling in Rashid Area of Nile Delta
(Egypt) via the Inversion of DC Resistivity Data". American Journal of Climate Change, 2016, 5,
147-156
Effect of Sea Water Intrusion on Nile Delta and Possible Suggested Solutions
Tarallo, D., Di Fiore, V., Cavuoto, G., Pelosi, N., Punzo, M., Giordano, L. and Marsella, E. (2014).
"4D Monitoring of sea water intrusion by Electrical Resistivity Tomography: case study in the
coastal alluvial plain of the Volturno River, Italy". Gruppo Nazionale di Geofisica della Terra
Solida (GNGTS), 25-27 novembre 2014, Bologna (Italy), Bologna, Italy; 11/2014
Werner, A.D., and M.R. Gallagher. (2006). "Characterisation of seawater intrusion in the Pioneer
Valley", Australia using hydrochemistry and three-dimensional numerical modelling.
Hydrogeology Journal 14, no. 8: 1452–1469
Westbrook, S.J., Rayner, J.L., Davis, G.B., Clement, T.P., Bjerg, P.L., Fisher,S.J. (2005). "Interaction
between shallow groundwater, saline surface water and contaminant discharge at a seasonally- and
tidally-forced estuarine boundary". Journal of Hydrology 302:255-269.
Yang C.H., Tong L.H. and Huang C.F. (1999). "Combined application of dc and TEM to sea-water
intrusion mapping". Geophysics, 64, 417-425, doi:10.1190/1.1444546.
Zahid, A., and Ahmed, S.R.U., (2006). "Groundwater Resources Development in Bangladesh:
Contribution to Irrigation for Food Security and Constraints to Sustainability", in: Sharma, B.R.,
Vilkoth, K., Sharma, K.D. (Eds.), Groundwater Research and Management: Integrating Science
into Management Decisions. Proceedings of IWMI-ITP-NIH International Workshop on “Creating
Synergy Between Groundwater Research and Management in South and Southeast Asia.”
International Water Management Institute (IWMI), pp. 27–46.
Zeidan, B.A., (2017), "Groundwater Degradation and Remediation in the Nile Delta Aquifer". A.M.
Negm (ed.), The Nile Delta, Hdb Env Chem (2017) 55: 159–232, DOI 10.1007/698_2016_128,
Springer International Publishing AG 2017, Published online: 15 March 2017
Zuurbier, K.G., Zaadnoordijk, W.J., and Stuyfzand, P.J., (2014). "How multiple partially penetrating
wells improve the freshwater recovery of coastal aquifer storage and recovery (ASR) systems": A
field and modeling study. Journal of Hydrology 509, 430–441.
