الفهرس 
GEOMORPHOLOGY AND HYDROMORPHOLOGIC FEATURESOnly 14 pages are availabe for public view
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Abstract
The sediments along the studied locality may be affected by the water currents as well as
hydro-morphologic features. The studied locality can be· divided into two main geographic parts
(southern and northern). The southern geographic part is characterized by its sinuosity,
relatively narrow width, shallow depth and narrow cross sectional area. However, the
northern geographic part is characterized by its low sinuosity, wide surface, deep bottom and its
large cross sectional area.
The western bank mostly slopes gently relative to the eastern bank. The deepest points along the
studied locality mainly exist in the eastern side. There is a wide spread of rocky irregularities
and ridges along the northern part.
The width increases northward from 360 m at profile 23 to reach about· 9800 mat profile 22. The
depth gradually increased from 10.5 mat profile 23 to reach 36 m at profile 22. The profile areas
increased northward from 2940 m2 to
reach about 217200 m2 at profile 22.
The interaction between sediments and water is mainly controlled by temperature, current regime,
pH, total dissolved salts and the dissolved nutrient salts concentration. The air temperature was
higher than the water temperature. Along the southern part, there was no variation in water
temperature and total dissolved salts between the surface and the bottom, (i.e.) one water mass.
Whereas, the downward decrease in temperature was established along the northern part that may be
referred to the width of the channel as well as the depth.
Along the studied locality, the current velocity decreases with increasing the profile area.
Therefore, it decreased northward from values reached 87 em/sec at profile 23 to values as low as 2
em/sec at profile 22. The pH values varied between 7.33 (slightly alkaline) and 8.55 (moderately
alkaline). Along. the southern geographic part, the pH values slightly increased northward from
7.43 at profile 23, to 7.72 at proflle 19 with nearly no vertical variation. North of profile 19,
there was nearly no change in pH values till the end ofthis part. Along the northern geographic
part, the vertical variation in pH values was established, whereas the average pH values increased
northward from 7.74 to reach 8.2. The electrical conductivity mainly tends to increase northward
due to evaporation, consequently, increases the total dissolved salts. The total dissolved
salts ranged between 131 mg/1 and 169 mg/1 with corresponding electrical conductivity values ranged
between 204 and 264 Jlmohs/cm respectively. Along the southern geographic part, the average values
of total dissolved salts tended to decrease northward ranging between 131 mg/1 and 156 mg/1. Along
the northern geographic part, the average values of total dissolved salts increased northward to
reach 165 mg/1 at proflle 22. The factors controlled total dissolved salts are the hydromorphologic
features as will as the nutrient· salts concentration. The nutrient salts are
represented by Silicates (Si02)
Phosphates (P04) Nitrates (N03-) and Nitrites (N02) where silicates formed the
main constituent. The total nutrient salts tended to decrease northward ranging between 7.71 mg/1
and 20 mg/1.
Water as a medium transports sediments from the upstream to the lake and from adjacent territories.
Recent sediments in the studied locality include two main constituents, the suspended matter and
the sediments laden on the bottom. The suspended matters increased downward, as well, it
intensively decreased northward from 915 mg/1 to reach 7 mg/1.
On the bases of the average distnbution of the suspended matters, the area
under investigation may be divided into two main enviromnents, riverine and. lacustrine. The
riverine environment located between lat. 21° i 55.35” and 21°
1 11
Q 1 tl 0 I
II
17 01.41 and long. 30 38 54.65 and 30 47 12.99, along which, the average
suspended matters increased northward from 439 mg/1 to reach 642 mg/1. The lacustrine environment
located between lat. 21° 1i 01.4( and 21° 57’ 13.26”
and long. 30° 47’ 12.99” and 31° 18’ 32.99”, may be differentiated into two main
geographic parts, southern and northern. Along the southern part of lacustrine environment, the
average suspended matters showed nearly no change. Along the northern part of lacustrine
enviromnent, the average suspended matters decreased northward to reach 13 mg/1.
The main factor affecting the suspended matters are the total dissolved salts, and the
current velocities. Along the riverine environment, there was no distinct relation between
suspended matters and total dissolved salts, whereas, along the southern part of the lacustrine
environment, the suspended matters decreased with decreasing the total dissolved salts. However,
along the northern part of lacustrine environment, the total dissolved salts may
assist the suspended matters to settle due to coagulation, so, the suspended matters
decreased with increasing the total dissolved salts. Along the studied locality, the suspended
matters decreased with increasing each of the profiles width, . depth and area. Along the
riverine enviromnent, although, the current velocity decreased northward, suspended matter
increased. Whereas, along the lacustrine environment, the suspended matter decreased with
decreasing the current velocity.
The riverine environment characterized by sand, silty sand, sandy clay silt,· clay silt and
silty clay sediments, whereas, the lacustrine enviromnent is characterized by silty clay and
clay sediments. Sand was found to be restricted
to riverine environment in which it decreased gradually northward. Silt content
ranged between 1% and 60% with an average 23%. Along the riverine environment, the average silt
content increased northward from 22% to 52% with an average 38%. Along the lacustrine environment,
the average silt content decreased northward to reach 12% with an average 19%. The clay content
ranged between zero % and 78% with an average 60%. The average clay content regionally increased
northward. Along the riverine environment, the average clay content increased northward from 11% to
39% with an average 25%. Along the lacustrine environment, the average clay content continued to
increase northward to reach 73% with an average 69%. The colloidal materials ranged between 0% and
19% with an average 11%. The average colloidal materials regionally increased northward (i.e.)
reflecting its relation to clay. Along the riverine environment, the average colloid co tent
increased from 1% to 6% with an average 4%. Along the lacustrine environment, the average content
increased to reach 15% with an average 12%.
The median diameter (Md0) ranges between 2.080 (fine sand) and 11.400 (very fme clay) with an
average 9.460 (medium clay). Along the riverine environment, the average values of Md0
increased northward from 3.860 (very. fine sand) to 7.680 (very fine silt) with an average 5.80
(medium silt). Along the lacustrine environment, the values continued to increase northward to
reach 10.920 (fme clay). It has an average 10.370 (fme clay). The mean size (Mz0) ranged between
2.110 (fme sand) and 11.260 (very fme clay) with an average
9.270 (medium clay). Along the riverine environment, the average values of Mz0 increased northward
from 4.060 (coarse silt) to 8.090 (coarse clay) with an average 6.140 (fine silt). Along the
lacustrine environment, the average values of Mz0 continued to increase northward reaching 10.490
(fme clay) with an average 10.050 (fine clay). In the riverine environment, the mean size Mz0 exceeded the median diameter Md0 whereas the median diameter Md0 exceeded the mean size Mz0 in
the lacustrine environment. The inclusive sorting o1 ranged between 0.62 (moderately sorted)
and 3.39 (very poorly sorted) with an average 1.91 (poorly sorted). Along the riverine
environment, the average value of inclusive sorting o1 increased northward from 1.3 (poorly sorted)
to 2.55 (very poorly sorted) with an average 2.16 (very poorly sorted).
Along the lacustrine environment, the average values of the inclusive sorting 01. decreased
northward to reach 1.71 (poorly sorted) with an average 1.85 (poorly sorted). The skewness
Sk1 ranged between -0.45 (strongly coarse skewed) and
0.39 (strongly fme skewed) with an average -0.18 (coarse skewed). Along the
riverine environment, the average value of skewness Sk1 is slightly increased northward, (i.e.),
the sediments tend to skewed toward the fme fraction. Along the lacustrine environment, the
average values of skewness decreased northward (i.e.) the sediments tend to skewed towards
the coarse fraction. The Kurtosis KG ranged between 0.66 (very platykurtic) and
1.60 (very Leptokurtic) with an average 0.96 (mesokurtic): Along the riverine
environment, the average values of Kurtosis KG decreased northward from 0.91 (mesokurtic) to 0.73
(platykurtic) with an average 0.88 (platykurtic). Along the lacustrine environment, the average
values Kurtosis KG increased northward to reach 1.26 (leptokurtic) with an average 0.98
(mesokurtic).
The main factor affecting the sediments distribution along the studied··
locality is the current velocity (especially along the lacustrine environment) that, in
turn, affected with the hydromorphologic features.
Along the studied locality, there are two main mechanisms of deposition,
river processes (in the riverine environment) and slow depositional processes from quiet water (in
the lacustrine environment).
The orgaruc matter content m bottom sediments increased northward
where it ranged between 1.26% and 12.78% with an average 9.71%. Along the studied locality, the
organic matter content increased with decreasing the grain size of the sediments. i.e., the area
under investigation is characterized by tme grain sediments contained organic matter, concentrated
in the lacustrine environment.
The carbonate content ranged between 5.05 %and 8.02% with an average
6.54 %. Along the riverine environment, the average distribution of carbonate content increased
northward, whereas, it decreased along the southern part of the lacustrine environment. Along the
northern part of the lacustrine environment, the carbonate content increased northward.
Along each of the riverine environment and the northern part of the lacustrine environment, the
carbonate content increases with decreasing each of the grain size and organic matter content.
Wherever, there was a reverse relation along the southern part of the lacustrine environment.
Along the studied locality, the carbonate content increases in the sediments with increasing the pH
of water.
X-ray diffraction analysis reflected that the bottom sediments composed mainly of clay minerals
including Momtmorillonite, Kaolinite and Illite in· addition to Quartz, Feldspar,
Calcite and Hematite. Quartz showed its maximum content at the riverine environment. Along
the southern part of the lacustrine environment, the quartz content decreased northward.
Along the northern part of the lacustrine environment, the quartz content showed nearly no
change. The feldspar showed its maximum content at the riverine environment, whereas,
there is no change in its content along the lacustrine environment. The calcite content showed
relatively lower values along the riverine environment compared with the southern part
of the lacustrine
environment. Along the northern part of the lacustrine environment, the calcite content increased
northward. The hematite shows its maximum content in the riverine environment, whereas, it
decreased northward along the lacustrine . environment.
Montmorillonite is the most abundant clay mineral followed by kaolinite,
whereas illite has a relatively low abundance. The abundance of montrnorilonite and kaolinite
increased northward along the studied locality, whereas, illite increased northward till reached
its maximum at profile D, then decreased farther north.
from the above mentioned discussion. the following conclusion are reached:
The area under investigation can be distinguished into two mam environments (riverine and
lacustrine) each of which has its own hydromorphologic, hydrographic and sediments
characteristics. The riverine
environment located between lat. 21° i 55.35” and 21° 17’ Ol.4t” and long. 30°
38’ 54.65” and 300 47’ 12.99...
The riverine environment characterized by its sinuosity in addition to its relatively narrow width
shallow depth and narrow cross sectional area. The eastern bank mostly slops gently relative to
the western bank.
Along the riverine environment, as the profile area increased northward,
the current velocity decreased, whereas, pH, electric. conductivity and total dissolved salts
(including nutrient salts) increased. The nutrient salts mainly included silicates (increased
northward) and phosphates (decreased northward) in addition to small amounts of nitrates (increased
northward) and nitrites (decreased northward).
Along the riverine environment, as the suspended sediments increased
northward, the bottom sediments characterized by relatively coarse grain (very
fine silt to very fine sand), where the mean siZe Mz0 exceeded median diameter Md0.
The northward decrease in the grain size accompanied by the change from poorly to very
poorly sorted and from mesokurtic to platykurtic giving rise for the sediment to be skewed
towards the fine fraction. Along this enviromnent, the river processes are the dominant
mechanism of deposition. The organic matter and carbonate contents were found in a
relatively low· abundance and increases in percentages northward. In the riverine environment,
quartz, feldspar and hematite showed its maximum content, whereas, calcite and clay
minerals including montmorillonite, kaolinite and illite, showed there minimum abundance.
The lacustrine enviromnent located between lat. 21° 1i 0 1.4I” and 21° 57’
13.26” and long. 30° 47’ 12.99” and 31° 18’ 32.99”. It may be differentiated into two main
geographic parts, southern and northern. The southern geographic part is characterized by its
sinuosity and its shallow depths, whereas, its profiles became wider and larger in area than that
characterizes the riverine enviromnent. In addition, the western bank slobs gently relative to the
eastern bank.
Along the southern part of the lacustrine environment, as the profile area continued to increase
northward, the current velocity, continued to decrease, whereas, electric conductivity and total
dissolved salts (including nutrient salts) decreased, however, the pH nearly did not change.
Along the southern part of the lacustrine environment, as the suspended sediments did not change,
the bottom sediments tended to be fme grained (fme to medium clay) where the median diameter Md0
exceeded mean size Mz0. The northward decrease in the grain size accompanied by the change from
very poorly to poorly sorted and from platykurtic to leptokurtic, whereas, it slightly skewed
towards coarse fraction. However, the slow deposition from quite water
was the prevailing mechanism of deposition. The organic matter content increased northward,
whereas carbonate content decreased. As the quartz and feldspar content decreased northward, the
calcite, hematite and clay minerals content including montmorillonite, kaolinite and illite,
increased.
The northern part of the lacustrine environment characterized by its low sinuosity, wide surface,
deep bottom and large cross sectional areas. In addition, the western bank slobs gently relative to
the eastern bank, whereas, there is a wide spread of the rocky irregularities and ridges.
Along the northern part of the lacustrine environment, as the profile area largely increased
northward, the current velocity rapidly decreased, whereas, pH, electric conductivity and total
dissolved salts (including nutrient salts) rapidly increased.
Along the northern part of the lacustrine environment, as the suspended
sediments rapidly decreased northward, the bottom sediments tended to be fme . grained (fine
clay) where the median diameter Md0 continued to exceeded mean size Mz0. Along this
part of lacustrine environment as the grain size changed in a very narrow range, the
sediments restricted to be poorly sorted, leptokurtic and strongly coarse skewed. Along this
part; the organic matter and. carbonate contents were found in a relatively high abundance
and increased in percentages northward. As the feldspar and hematite content continued
to decrease northward, the quartz showed nearly no change, whereas, the calcite and clay
minerals content including montmorillonite, kaolinite and illite, continued to
increase.