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Geomatic study of Shatt Al-Arab delta , southern

Sahar T. Al-Mulla Ali K. Al-Ali

University of Basrah , College of science , Department of Geology

[email protected] [email protected]

Abstract The present research aims to monitoring the environmental changes in shatt Al-Arab delta area southern Iraq . Remote sensing and Geographic information system (GIS) were used to achieve the objectives of this study . Satellite images of Landsat were used to study the coastal landforms for the years of 1972 , 1985 , 2006 and 2014 . Change detection is the main approach in this study were the differences in area are calculated . The result showed the shores of the delta is gradually Changed, perhaps because of the decline in river discharges of and , and thus a decline in volumes of suspended deposits that contribute for construction the beaches and deltaic marine barriers . the study showed a progress in areas of marine sabkhas and supratidal flats. as shown in satellite Images there is widening in cross section of the Shatt al- Arab channel with gradual drift towards the Iraqi beaches.

Keywords : Geomatic , Delta geomorphology , Change detection , Shatt Al-Arab

1. Introduction continuously . It is result from natural balance of the processes that The term "Delta" refers to one of interact with each other near river the most complicated sedimentary mouth . The Shatt Al-Arab delta is environments due to geological and considered as a part of Arabian gulf physical variables that belong to its within Iraqi border and it has creation(Ana et.al,2009) .As it is coordinates of ( 48° 21′ 0″ ) to (48° known , the delta characterized of 45′ 0″) longitude and (92 °45 0′ high sedimentation rates which make 0″) to (30°0′ 0″) latitude ,fig.(1) the form of delta is changed MARSH BULLETIN 10(1) 2015 | P a g e 37

Fig( 1), bathymetric map of Arabian Gulf

southeast trending Zagros fold belt. The river is formed by the The most controlling factors of the confluence of the Tigris and delta of Shatt Al-Arab are tidal Euphrates Rivers, which flow currents ,waves and winds , in through central and eastern Iraq. A addition to the physiography of the third river, the Karun River, which area . Delta is also affected by fluvial flows in west-central Iran and drains upstream suspended and bed loads . the Zagros mountains joins the Shatt this type of delta is characterized by el Arab waterway just north of the the longitudinal sediment bars , modern delta, With a total length of which are deposited in the channel 192 km, the Shatt al Arab widens near the river estuary . The only over its course, expanding from a tributary of Shatt al-Arab river is width of 250-300 m near the Karun river , and most of the former Euphrates-Tigris confluence to sediments are supplied from the local almost 700 m near the city of Basrah sites (Albadran,2005) and more than 800 m as it approaches the river mouth. An area Geologic setting of 45,190 km² drains directly to the Shatt al Arab region downstream of The Shatt Al Arab river flows in the Euphrates-Tigris confluence the Tertiary and Mesozoic northwest- (excluding the Euphrates and Tigris MARSH BULLETIN 10(1) 2015 | P a g e 37

Basin areas). Several tributaries join Tigris and the Euphrates Rivers has the Shatt al Arab during its course, been significantly reduced for the last most importantly the Karun Rivers. 50 years. Figure (3) shows the annual The Shatt al Arab Delta area is water discharge of the Two Rivers classified as estuarine-deltaic into the Mesopotamian marshlands because the river’s sediment seeps from 1940 to 2007. The regression into a shallow, narrow part of the line shows the graduate reduction of Arabian Gulf, ( Bundesanstalt ,2013) the Two Rivers’ water discharge . The Tigris and Euphrates Basin , during the recorded period. the Arabian Gulf, occupies a zone of Generally, the figure indicates two subsidence depression surrounding periods of water discharge reduction. by mountains and desert,fig (2),This The first period was during the elongate depression was formed 1970’s, in which many dams were during an era of mountain building constructed at the Tow Rivers’ initiated early in the Tertiary that upstream in Turkey . The second continues with the movement of the period was late 1990’s, when the Arabian plate against the stable Iraqi government started drains the landmass of Asia. The drainage basin marshlands. During the pre-dam, the of these three rivers covers an area of annual water discharge of the Two 793,600 sq km. The average annual Rivers into the Mesopotamian river discharge is 1,966 cu m/sec marshlands from 1940 to 1970 was with a maximum of 3,299 cu m/sec about 84.6 × 109 m3. After this and a minimum of 849 cu m/sec The period until 1990’s, the main channel is some 2,658 km long Mesopotamian marshlands lost more and debouches into the Arabian Gulf, than 30% of their annual water (Oscar K. Huh, James M. Coleman, discharge. The situation of water 2004) . Different estimates have been shortage become more complicated provided by several authors for the overtimes, unfortunately, the current yearly averaged transport of this annual water discharges of the two group of rivers: from 160 m3/s to Rivers are still decreasing, and its 3150 m3/s . a value of 1400 m3/s is average value from early inundation usually retained for this average in 2003 to 2007 was about 13.8 × transport. Furthermore, the transport 109 m3. This indicate that is quite variable with seasons (from the Mesopotamian marshland have 700 m3/s in October to 5700 m3/s in lost more than 80% from their April) . Along the Iranian coast, historical water input. This situation rivers Hendijan, Hilleh and Mand is dramatically affecting the current would carry 2034 m3/s . this should hydrological conditions of the re- be confirmed and their variability flooded marshes. This also indicates should be determined, so that further that the existing quantity of water in studies could take them into account. the Two Rivers is not enough to re- For the moment ( Pous et.al ,2013). cover the historical Mesopotamian’s The annual water discharge of the MARSH BULLETIN 10(1) 2015 | P a g e 37 size. On the other hand ( AlMaarofi et.al ,2012)(Purser,1973)( fig , 3).

fig 2, multispectral satellite image of study area & surrounds

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Fig 3. Annual water discharge of the Tigris and the Euphrates Rivers ( AlMaarofi , Douabul , and Al-Saad , 2012)

Climate northwesterly with an annual mean of 5 m/s. This dominant wind is The climate in the Shatt al Arab called Shamal and it blows regularly region is hot and arid. Based on data in summer, while wind bursts can from the city of Basrah, average occur in winter. These bursts are temperatures in the Shatt al Arab preceded by episodes of southerly region vary from 9°C to 41°C; winds called Kaus. The precipitation temperature lows occur in January, rate is very weak in the Gulf: it highs in July. Annual precipitation amounts to 7 cm/year for the whole rates range from 100 mm in the , which is 4 times western part of the delta to about 200 smaller than the river discharge . mm in the east. The city of Basrah Evaporation is very strong but its has a mean annual precipitation of estimates are quite variable, from about 100 mm.By contrast, cold 144 to 500 cm/year . a value of 200 winters and mild summers are the cm/year has been used in recent work norm in the northern, more . The deficit in freshwater for the mountainous areas. Temperatures whole Persian Gulf is therefore on across the basin vary from a the order of 416 km3/year which minimum of -25°C in winter to a confers characteristics of an maximum of 50°C in summer ,( evaporation basin to this gulf. , ( Bundesanstalt,2013). Winds over the UNEP,2011). Arabian Gulf are dominantly MARSH BULLETIN 10(1) 2015 | P a g e 37

Tides larger than 10 cm/s, along the coasts and in shallow areas of the In the western part of the Gulf, the southeastern part of the Gulf (where surface current is mostly depths are smaller than 30 m). southeastward in the shallow areas Bottom currents are weaker than near the coasts and northwestward in their surface counterparts and do not the deeper area (fig ,4 ).This forms a exceed a few cm/s. Close to the double gyre system. In the eastern coasts and in shallow areas, the part of the Gulf, the cyclonic gyre bottom currents are southeastward or becomes dominant. A southeastward eastward (like the surface currents), current exists along the Iranian coast and in the central, deeper, part of the despite the presence of this cyclonic Gulf, , ( Pous et.al ,2013). structure. This circulation is controlled by the wind, by bottom topography and by the shape of the basin. The current is surface- intensified, with maximal amplitudes

Fig (4 ) the surface circulation in the Arabian Gulf , (Reynolds,1993)

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Delta morphology devoid of extensive vegetation where salts are deposited (fig 5). The alluvial valley of each of the Dark gray areas that border the bell- three rivers are fairly well defined shaped river mouths and tidal and the channels display a channels correspond to new fine- meandering tendency, with grained sediment deposits that stretches of braiding where periodically experience tidal tributaries enter the main channels.. inundations. They support a growth controlled mainly by topographic of salt-tolerant vegetation (mainly variations outside the delta. The blue-green algal mats). Freshwater Shatt el Arab delta is located at the wetlands just north of the active northern end of an elongate shallow delta support fresh water sea where semidiurnal tidal vegetation. and this area is actively variations reach about 2.5 m. subsiding, but receives a large Although much of the delta is made percentage of the sediments of the up of broad marshes and associated Tigris and Euphrates Rivers forming lowlands that are valuable as delta morphology , (Goddard earth agricultural lands, most coastal science data,2009). regions are tidal flats and sabkhas

Fig (5) multispectral scene 2,5,7 for Shatt Alarab and surrounds MARSH BULLETIN 10(1) 2015 | P a g e 78

Delta characteristics systems lie along the dominate the prograding delta front. average wave The shatt Alarab delta has only two power being 0.014 x 107 ergs/sec/m active distributaries, and in its lower coast and the average leading edge course, the natural levees are of the delta. Mudflats and sandbars covered with mangrove vegetation. dissected by tidal channels root The inter distributary areas consist mean square wave height is 0.99 m predominantly of salt flats. The delta ,).the main tidal range 2.5 meter Due area is some 18,497 sq km in area , to Where seawater is trapped during (fig 6 ). much of the modern delta very high (storm) tides, salt pans plain is inactive or abandoned. develop. White areas in the scene Immediately to the north of the are barren regions of salt deposition modern delta is a large tidal basin along with gypsum/anhydrite. displaying intricate tidal channels Offshore from the river mouth are and broad unvegetated tidal flats. broad elongate subaqueous tidal The delta depths ranging between ( ridges that form in response to tidal , 1) - (-15)meter.The wave energy (Oscar et.al 2004). along the delta shoreline is extremely low, the low wave energy, figs ( 7,8, 9,10) shows the main only narrow beaches and small dune deltaic

Fig(6) Shatt Alarab Delta & Arabian gulf bathymetry by (Zhao et.al ,2014) MARSH BULLETIN 10(1) 2015 | P a g e 78

Fig ( 7 ) illustrate the main delta wave height properties compare with other deltas in the worlds, (Oscar et.al 2004).

Fig ( 8 ) illustrate the main Delta Shatt Al-Arabs´ tidal range properties compare with other deltas in the worlds, (Oscar et.al ,2004). MARSH BULLETIN 10(1) 2015 | P a g e 78

Fig ( 9 ) illustrate the Delta Shatt Alarabs´ shoreline length/ width compare with other deltas in the worlds, (Oscar et.al ,2004).

Fig ( 10 ) illustrate the main delta Shatt Al-Arabs´ Delta area properties compare with other deltas in the worlds, (Oscar et.al ,2004).

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Methodology surface landforms . The data used for delta monitoring were acquired by Remote sensing data are mainly landsat from the time period of 1972 used in this study for land cover , 1985 , 2006 and 2014 , Table(1). monitoring of both surface and sub

Table(1) Satellite images criteria

No. Date Sensor Resolution 1 1972 MSS 60m 2 1985 MSS 60m 3 2006 TM 30m 4 2014 OLI 30m

1.1 Data processing ;landsat OLI as R,G,B format were used to enhanced the objects and By using Erdas Imagine 9.1 recognized clearly between software , a land cover maps were vegetation , mud , clay , soil and classified using un supervised water . The files of bathymetric classification (Maximum Likelihood analysis maps were interpolated in method) . The extent area for each shape file format using Arc tool box item in land cover maps were of Arc Gis 9.3 software (Idw calculated . The composite image method).fig (11 ) and by quantities 7,5,2 bands in landsat ETM+ , 3,5,7 charts ( 12,13,14 ).

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Fig(11) Idw interpolation method for the shatt alarab bathymetry by arcgis 9.1

Fig ( 12 ) illustrate the main shatt alarab delta coastal properties by arcgis 9.3 MARSH BULLETIN 10(1) 2015 | P a g e 77

Fig ( 13 ) shatt alarab delta coastal properties compare with other world’s major delta

Fig ( 14 ) shatt alarab delta coastal properties compare with other world’s major delta MARSH BULLETIN 10(1) 2015 | P a g e 77

Change detection and Image classification for the successive classifications years show there is an openings at the entrance of Shatt al-Arab Four photo maps of land channel in gulf side clearly in cover and sub surface landforms satellites of the period from were created using un 2006 to 2014 and the decline in supervised classification . The the areas and area of each object were calculated for the years of 1972 , extensions of murkats Abadan in 1985 , 2006 and 2014 the east and Khawr Abd Allah respectively , concluded in westward , with the clear coastal Table(2) fig.( 16,17, 18, 19). The erosion of longitudinal barriers results of the digital and the islands that were classification of satellites Images adjacent to two murkats in the clearly showed a decline in channel entrance in the satellite wetted tidal flats areas (the images of the period from 1972 intertidal flats and subtidal flats ) to 1985. slowly curvature also with an increase in the areas of showed clearly in outer limits of subratidal flats tide and coastal delta murkats as a result of sabkas This is a sign of affected waves erosion, with slowly of Delta Shatt al-Arab with the creep of Murkat Abadan environmental and hydrological westward. Table (2),figs changes in the Upper Delta, as (15,16,17,18). well as the results of

Table(2) Results of Digital classification (area in km2)

Salt Supratid Intertida Subtidal Deep Year sabkas basins pans al flats l flats flats water

1972 54.328 141.48 193.547 160.355 251.687 437.905 1233.52

5891 1.659 163.944 427.542 328.1 809.09 504.886 425.144

1085.97 85.964 145.033 393.61 108.2 63.017 487.256 6002 3

1757.05 6.629 86.876 335.54 178.767 184.305 220.029 6052 8 MARSH BULLETIN 10(1) 2015 | P a g e 73

Fig(15) unsupervised classification of Shatt Al-Arab delta for 1972

Fig(16)unsupervised classification of Shatt Al-Arab delta for 1985 MARSH BULLETIN 10(1) 2015 | P a g e 77

Fig(17)unsupervised classification of Shatt Al-Arab delta for 2006

Fig(18)unsupervised classification of Shatt Al-Arab delta for 2014

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Digital Change detection of sedimentation, especially in flats of Khawr Abd Allah, as well as the Another digital method is for breadth of areas of Marqat Abadan monitoring the changes in study area, and Marqat Khawr Abd Allah that by convert the Raster files to make up the main wings of the Shatt polygons in Arc GiS program in al-Arab Delta. The same thing order to statement the changes in the applies to the period between years boundaries and areas of the coastal 2006-2014, as shown gradual units in a successive periods of time. widening in delta Marqats For example, for the period between mentioned above , as well as years 1972 and 1985 as well as increasing in drift of Shatt al-Arab between the years 2006-2014 . The channel to the West toward Iraqi comparison between the time coast. It is interesting to consider the visualizations for digital image Narrowed that has occurred in cross- process showed that the most section of the Shatt al-Arab channel important changes in the region was in the lower part of it in a year 2014 in the expansion in the cross-section compared to year 2006, Due to the of the Shatt al-Arab channel, as well low volume of river discharges as it’s the advance and changes in across the Tigris , Euphrates and the channel direction that have Karun in recent years and increased occurred in it . the digital change the fluvial sedimentation process detections showed the intensification .figs (19, 20).

Fig(19) change detection in delta coasts & areas of years 1972- 1980 MARSH BULLETIN 10(1) 2015 | P a g e 78

Fig(20) change detection in delta coasts & areas of years 2006- 2014

Conclusions because of the decline in river discharges of Tigris and Euphrates , Delta Shatt al-Arab subject to and thus a decline in volumes of numerous operations contributed to suspended deposits that contribute the formation . the most important for construction the beaches and factors , tides, coastal currents , river deltaic marine barriers with advances discharges and gradual slopes of the in areas of marine sabkhas and Mesopotamian Continental shelf , supratidal flats. as shown satellite Through digital interpretation of Images there is widening in cross satellite Images for a successive section of the Shatt al-Arab channel years observed the shores of the delta with deviation gradually towards the is gradually declining, perhaps Iraqi beaches.

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References Department of oceanography and coastal science , Louisiana state  Albadran(2005),Delta of Shatt Al- university. Arab Delta –south of Iraq-  Pous,s.;carton,x. and sedimentological study,Marina Lazure,p.(2013),A process study of Mesopotamia the wind induced circulation in the  AlMaarofi,s.;Douabil,A.and Al- Persian gulf;open journal of marine Saad,H.(2012),Marine science;vol.3,no.1. Environmetal Chemistry, Marine  Purser,B.H(1973),The Persian Gulf , science centre publications , Holocene carbonate sedimentation University of Basrah. ,springer , 471p.  Ana,R.E. , Sridhar,M.K. and  Reynolds,R.M.(1993), Physical Emerole,G.o.(2009),A comparative Oceanography of the Persian Gulf, assessment of soil pollution in Niger Strait of Hormuz, and the Gulf of Delta , Nigeria African Journal 3(3). Oman , Marine Pollution Bulletin,  Bundesanstalt,F.G.(2013),Shatt Al- Pergamon Press, London. Arab , Karkheh and Karun Rivers ,  UNEP(2011),Environmental United nations economic and social Assessment of ogoniland , United committee for western Asia , Nation Environmental Program Inventory of shared water resources  Zhao,j.;Temimi,M.;Ghedira,H. and in western asia,Beirut. Hu,c. (2014),Exploring the potential  Goddard earth science of optical remote sensing for oil data(2009),Shatt Al-Arab Delta , spill detection in shallow coastal IRAQ. water a case study in Arabian  Oscar,k.H. ; James,M.C. and gulf,optics express,vol.22,issue Dewitt,B.(2004),Coastal studies, 11,pp,13755-13772.

دراسة جيومعلوماتية لدلتا شط العرب جنوبي العراق

سحر طارق المال علي خالد العلي

جامعة البصرة – كلية العلوم – قسم علم االرض

المستخلص

هذا البحث هو دراسة جيومعلوماتية لمنطقة دلتا شط العرب، يهدف إلى رصد التغيرات البيئية في منطقة الدلتا جنوب العراق. استخدمت تقنيتي االستشعار عن بعد ونظم المعلومات الجغرافية (GIS) لتحقيق أهداف هذه الدراسة. تم استخدام صور األقمار الصناعية االميركية الندسات بمتحسساتها ) MSS,ETM+,OLI) لدراسة التضاريس الساحلية للدلتا لسنوات متتابعة من 8738 و 8777 و 8887 و 8887. كشف التغيير الرقمي يمثل المنهج الرئيسي المعتمد في هذه الدراسة لحساب التغييرات البيئية . أظهرت النتائح حدوث تغيرا تدريجيا لشواطئ الدلتا ومسطحاتها المدية ، يعود السبب الى تدني التصاريف النهرية لنهري دجلة والفرات وانقطاع مياه نهر الكارون عن شط العرب ، وبالتالي انخفاض في حجم المياه والرسوبيات مع التي تسهم في بناء الشواطئ والحواجز البحرية الدلتا. وأظهرت الدراسة تقدما في مجاالت السبخات البحرية ومسحات اعالي المد والجزر .كما بينت مرئيات األقمار الصناعية ان هناك اتساع في المقطع العرضي لقناة شط العرب عند مصبه في الخليج العربي.

الكلمات المفتاحية: الجيومعلوماتية , جيومورفولوجية الدلتا , رصد التغير , شط العرب