الفهرس 
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Abstract
The present work is an attempt to evaluate the groundwater
potentiality ofthe Quaternary aquifer in the middle part of EI-Qaa plain,
which lies parallel to the Gulf of Suez in the western part of Sinai
Peninsula. The importance of EI-Qaa plain lies in the fact that it is one of
the most promising areas in Sinai Peninsula for integrated development
due to its even surface, easy access, presence of groundwater resources
and strategic location.
The main objective ofthe present study is to recognize in detail the
characterstics of the Quaternary aquifer. This is important because most
of the previous studies carried out in the area was on a regional scale for
the whole area of EI-Qaa plain which is much larger than the area studied
here. Besides, these studies were not as integrated as is regarded here.
To fulfil this objective, a geoelectrical survey was carried out in the
area to reveal the subsurface succession including the water-bearing
formation, define the aquifer geometry (depth, thickness and extension)
and determine the approximate water quality in the different parts of the
aquifer. The Transverse Unit Resistance and Average Transverse
resistivity were correlated with the two corresponding hydraulic
parameters; namely the aquifer Transmissivity and Hydraulic
conductivity calculated from pumping test data. Chemical analysis were
applied to water samples obtained from several wells in the area to
determined the water salinity, hardness, and type, concentrations of the
different chemical elements and suitability of water for different
purposes. Comparison was made between the distribution of the water
quality as concluded from the actual chemical analysis and that concluded
from the geoelectrical survey.
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The geoelectrical survey involved carrying out 39 Vertical
Electrical Soundings (YES), Jell distributed across the area along nine
profiles. Six of these soundings were carried out at the locations of wells
of known lithologic logs to correlate geoelectrical and geological data.
Using the Schlumberger electrode arrangement during field
measurements, the spacing of the current electrodes was varied from 2m
to 2000m at each sounding station.
The qualitative and quantitative interpretation of the sounding
curves using the methods of Velpan (1988) and Zohdy (1989) indicated
that the subsurface of the area down to the investigated depth consists
mainly off our geoelectricallayers as follows from top downwards:-
I-A surface layer varying inthicklless from few meters to 12m,
characterized by a wide range of resistivity (20-15122 Ohm.m.). This
layer consists of sand, gravel and boulders drived to the plain from the
surrounded highlands.
2-A dry layer consists of sand and gravel but with a relatively narrower
range of resistivity (12-329 Ohm.m). The thickness of this layer varies
from 2 to 52m.
3-A water-bearing layer with a thickness of 3D-86m.’ and a narrow range
of resistivity of 3-89 Ohm.m. This layer consist also of sands and
gravel with some clay intercalation.
4-A water-bearing layer, which represents actually the downward
extension of the overlying layer as it is more or less similar in its
lithologic composition. However, the water quality of this layer is
lower as it is characterized by both low and narrow range of electrical
resiustivity (1-23 Ohm.m). The thickness of this last layer was not
determined because of the principle of the D. C. electrical exploration
itself and regarding the great thickness of the Quaternary aquifer.
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However, the thickness ofthis layer-within the present explored depthis
expected to be not less than 50m.
The interpretation of the electrical soundings indicated also that the
water-bearing formation extends across the whole studied area with its
top at a depth of 3.2 -65m from the ground surface.
The resistivity distribution of the water-bearing formation indicated
that the middle and eastern parts of the area have the relatively best water
quality while the western and southwestern parts have the least water
quality. This was confirmed later by the chemical analysis of water
samples.
The results reached from the geoelectrical measurements and
interpretation are illustrated in the form of graphs, contour maps vertical
section and cross sections.
The analysis and interpretation of the pumping test data using the
methods of Theis (1935), Jacob (1947) and the recovery test curves
together with rather recent computer programs indicated that the
hydraulic conductivity of the aquifer ranges between 1.26 and 71.5 m/day
and its transmissivity ranges between 100 and 1900 m2/day. This points
out to an aquifer of good potentiality. The reached parameter values were
found to be in agreement with the values determined before by
conventional computation methods.
The comparison of the hydraulic parameters with the
corresponding geoelectrical parameters indicated that the two groups of
parameters are directly proportional to each other in such a way that from
the measured geoelectrical parameters it would be possible to expect the
behavior of the corresponding hydraulic parameters in the different parts
of the area and consequentlyjudge upon the aquifer potential before the
drilling of the water wells.
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The chemical analyses of water samples carried out by the author
indicated that the aquifer water is chemically favorable for human
drinking purposes except water samples No.5, 12,15,22 and 23 according
to international standards. As to irrigation and water use by livestock and
poultry, the water of all parts of the aquifer are acceptable except sample
No.23 due to high salt concentration and high Sodium Adsorption Ratio.
The concentrations of each of the determined chemical elements
present in the aquifer across the area are given in the form of contour
maps, tables and diagrams.
According to the results and conclusions reached from this study,
the following recommendations can be presented: -
1- For future drilling of groundwater in the area, the middle parts of the
study area are recommended as they are characterized by the
following:-
a- appropriate depth to top of the aquifer (20-30m.).
b- Good water quality as the total water salinity is less than in the other
parts of the study area.
c- Relatively higher values of Transmissivity and Hydraulic conductivity
of the aquifer.
d- Relatively greater thickness of the upper part of the aquifer where the
water quality is better.
2- The total depth of any of the water wells to be drilled in the area in
future should be in the range of 75 - 125 m according to the
topography of the area and thickness of the upper part of the aquifer
where fresh water is present.
3- The present pumping rates of wells Nos.9, 25, 27 and 28 should be
reduced to allow for higher well Specific Capacity and well efficiency
and lower well loss and aquifer loss.
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4- Use could be made of the ”Transverse Unit Resistance” and” average
Transverse Resistivity” calculated from the electrical sounding curves
in differentiating between areas having high and low values of the
aquifer Transmissivity and hydraulic conductivity prior to well drilling.
5- The use of water derived from wells Nos. 5, 12, 15, 22 and 23 for
drinking purposes should be re-considered as the chemical contents of
this water don’t agree with international standers. Similarly, water
derived from well No. 23 should be avoided as drinking water for
livestock and poultry for its high salt content and high sodium
adsorption ratio (SAR).
It has to be mentioned here that the geophysical study carried out
in the present work was able to yield more successful picture about the
characteristics of the Quaternary aquifer when it was linked to a
complementary hydraulic investigations and chemical analyses.