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The Mesopotamian Geographic
researches..
The Properties of Iraqi Coast
" Geographical Study "
Hasan Khaleel Hasan Al-Mahmood
*
Abstract
Geographical study was carried out on the Iraqi coast of
the Arabian Gulf. The coast is located in the extreme
south of Iraq between latitude 29° 49 ´
000 ´´ and 30° 05´
012 ´´ N and longitude 48°
01 ´ 006 ´´ and 48
° 44 ´ 000 ´´ E. This
coast consists of a Coastal Sabka which extends about
(27 km) towards the north. , covering on area of (736
km2 ), the other part of the study area is
tidal flats with a gentle slope toward the Gulf. The
length of the tidal flat is 64 km and its width varies
with the sedimentation nature, it is 15000 m near the
Shatt Al-Arab estuary to 100 m a narrow strip near the
southern entrance of Khor Al-Zubair.
This study based on the information and data of field
and laboratory. The field work was carried out during
Aug. and Oct. of 2004 and Jan. and Feb. of 2005. Aerial
and image processing and admiralty charts were applied
for geomorphic zone identification, bathymetry and the
geologic development of tidal flat and the Shatt Al-Arab
Delta.
Geologic setting, climate of temperature( 36.5 °C),
relative humidity of (61%), high evaporation of 3655 mm,
precipitation less than 120 mm, and wind speed of more
than (6m/sec) produce a coastal sabkha, which was
extended due to the lack of vegetation cover, high
relief and level of chemical ions in the ground water,
in addition to the human activities.
The origin of the sediments is from the Shatt Al-Arab
and Karun Rivers, and little amount from Aeolian and
marine origin. The general means of clay, silt and sand
percentage are 30, 63 and 7 respectively. The texture is
silty to silty- clay and mixture. The chemical
properties of soil characterized by a high pH, it ranges
from 8.1 to 8.7, EC is 33-37 mmohs/cm, gypsum and
calcium carbonate are 3.27-28 and 5.42-59% respectively.
Calcium, sodium, magnesium and potassium are in the mean
0f 1925, 8449, 1057 and 262 mg/l respectively, whereas,
the chloride, sulphate and bicarbonate are 13299, 3364
and 117 mg/l respectively. The organic matter is from
0.99 to 4.1%. Moisture content, liquid and plastic
limits are 33-50, 31-48 and 20 – 28% respectively.
The chemical composition of coastal water was a high
salinity, it varies between 24.3 and 39 ppt, and
Phosphate, silicate, nitrate and nitrite are in the
range 1.5-3.2, 3.5- 41, 0.9-7.3 and 0.6-1.5 micr-gm/l
respectively. Sodium, calcium, magnesium and potassium
vary between 9200-19502, 403-429, 1134-1654, and 204-381
mg/l respectively. Chloride, sulphate and bicarbonate
are 14825-16575, 1301-2543 and 132-336 mg/l
respectively. The alkalinity is 124-184 mg/l and the
hardness is 1222-1800mg/l.
The depth of ground water varies during dry and wet
seasons between +10 cm respectively in the inner tidal
flat and 112 cm in the supra tidal flat. The salinity of
the ground water of the inner and outer tidal flat
during the dry season is 54 and 234 ppt, for the wet
season respectively. The pH is 6.6 -7.9, and the total
dissolved salts of the inner and outer tidal flats is
28595-30526 and 40005-41915 mg/l respectively.
The effects of winds, coriollis force, and river flow
are notable on the wave and tidal currents generation.
The dominant currents are the tidal and the
southeastern winds induce to increase the tide level and
water velocity, whereas, the northwestern winds
accelerate the ebb tides. The mean surface water current
of ebb in the southern entrance of Khor Abdallah is 1.07
m/sec, and it is 0.85 m/sec near the southern entrance
of khor Al-Zubair, and 1.13 m/sec near Ras Al-Bisha. The
direction of the water currents is along the axis of
khor Abdallah, for that, the sedimentation is an active
near the Shatt Al-Arab River estuary, whereas, in
balance between sedimentation and erosion in the western
coast.
The gentle slope nature of the coast allow the
arrival of direct waves, which is of failure- type. The
shallow depth affect on the height and activation of
waves and their effects on the coast. The waves are
inactive and their height is no more than 2.33m, due to
the(South-South-East) Wind, which happen during (March).
It is noted that the high sedimentation rate is related
to the shallow depth , The bigger depth no more (5 m),
and the shallow geomorphologic units appear near the
coast, whereas, the deeper under water channels appear
far from the coast. For that, the plate -form ports are
constructed in the deeper part as Al-Baker and Al-Umaya.
The area of the tidal flat in the east increases from
126 to 134 km2 between 1986 and 2004,
whereas, it is eroded by 4 km2 in the west
for the same period. The progradation of the delta is
about 3000 m. near Ras Al-Bisha. The Iraqi coast is
classified as bending and geologically stable coast, and
neutral flood coast produced from river and marine
factors, The origin of the sediments is from flooding
and identical in their asymmetrical distribution. The
development of Iraqi coast needs to support by
scientific studies, take off the marine waste and the
treatment of the sabkha and local lakes in the area.
*
A Thesis Submitted to
the Council of the College of Arts – University of
Basrah In Partial Fulfillment Of The Requirements For
The Degree. Of PhD In Physical Geography
By: Hasan Khaleel Hasan Al-Mahmood
E-mail:
[email protected]
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