Overall Geomorphology of the Tigrea-Euphrates Catchment - Term Paper Example

NAME: STUDENT NUMBER: UNIT: INSTITUTION: INSTRUCTOR: TOPIC: A DESCRIPTION OF THE OVERALL GEOMORPHOLOGY OF THE TIGRIS-EUPHRATES CATCHMENT. DATE: See UNEP/GRID Arendal Maps and Graphics Library, Regulation of the Tigris and Euphrates rivers, http://maps.grida.no/go/graphic/regulation_of_the_tigris_and_euphrates_rivers (Optional description here) (as of Jul. 21, 2009, 09:38 UTC). INTRODUCTION River systems are by their very nature extremely complex systems and a catchment system will normally contain a vast amount of varied landforms. These will often vary according to the position in the river system and the nature of the river itself (Lesschen: 2002:2). The Tigris and Euphrates Tigris Rivers rise in the mountains of eastern Turkey then converge into the sea at the head of the Persian Gulf. The catchment spans from the Syrian region of Karkamisk through Turkey into Cizre then enters Iraq at Faysh Khabur. From here, it acquires various tributaries such as the Adhaim, the Greater Zap, the Lesser Zap as well as the Diyala from the Zagros Mountains to the east where the Tigris and Euphrates finally join together near Qurna in Iraq (Kaya, 1998). The Tigris-Euphrates catchment system is undoubtedly one of the world's main ecosystems and is rightfully considered to be the cradle of civilization. As such, it has long been a focus of historical and scientific research. Consequently, a wealth of information has been obtained concerning the soils, environment, fauna, flora, settlement patterns, artifactual history and land use through the use of archaeological, hydrologic, and geomorphologic research. A full assessment of tectonic movement, sea-level oscillation, alluviation, river shifts, and long-term patterns of climatic change has been hampered by a lack of data from Iraq, although important information on some of these processes has been obtained by studying the Persian Gulf. The following discussion will thus focus on providing an overview of this Tigris- Euphrates catchment system by analyzing the various landform types that are contained within it; the geomorphological processes that characterize it; as well as the man made features that have altered its landscape among other things. This will be critical in creating an understanding as to the importance of this prominent, historical river catchment system. A). A SUBDIVISION OF THE CATCHMENT INTO LANDFORM TYPES 1. Alluvial Plains: Due to the fact that the waters are greatly silt- laden and the consistent deposition of sediment in the Tigris- Euphrates catchment over several centuries, there are many alluvial plains that do the basin. There is the Mesopotamian Plain) which is a central flood plain covered by flat lying alluvium deposited by the interacting Tigris and Euphrates. The plain is surrounded by the alluvial fans resulting from Jezira in the NW, the Hemrin- Pesh- e- Kuh range in the NE and the desert plateau in the SW (Jassim and Goff, 2006: 253). Apart from the Mesopotamian plain, various other alluvial plains dot the basin. These include several in the Diyālá region which is North- East of Baghdad, the Khūzestān plain of Iran which borders Iraq, the alluvial plain south of Samarra and Al- Ramadi as well as the southern alluvial plain. Within all these alluvial plains, there exists The 7,000 years of irrigation farming on the alluvium have created a complex landscape of natural levees, fossil meanders, abandoned canal systems, and thousands of ancient settlement sites (Al- Uzaym, 2009).   2. Gorges: As with most river catchment systems, gorges are a prominent feature due to the fast- flowing stream of both the Tigris and Euphrates that result in deep cutting erosion. Consequently, there are many gorges in the system. For instance, near Elaz at the Keban Dam there is a very deep gorge. Another notable example of a prominent gorge is the Rū Kuchūk gorge which is located north- east of Barzan and was formed by the heavy dissecting action of the Diyala, Great Zab, Little Zab and Uzaym streams as well as the Bekma gorge which is towards the west of Rawāndūz (Al- Uzaym. 2009). These are among the most prominent gorges in the basin. 3. Terraces: There exist terrace deposits in the system with the largest number of terraces found in western Iraq. This is particularly so in the vicinity where the Euphrates leaves the uplands of the Arabian Platform. In most areas, there are no more than six terraces though a lot of them have been classified as being multiple terraces. (Demir, 2007) These terraces were formed due to the transportation of gravel from Anatolia as a result of regional uplift. In addition, in the north of this Arabian Platform in the Diyarbakır area which is in the South East of Turkey there are several staircases of terraces while approximately nine terraces in the Tigris which are very prominent, the highest being 200m in (Springer Berlin, 2007). 4. Deltas: Deltas are yet another example of features in the Tigris- Euphrates river catchment system. The Shatt al Arab delta is most notable and is formed when the Euphrates merges with the Tigris to form the Shatt al Arab delta. (Jassim and Goff, 2006: 253). It is a 193 km long delta and flows South East to the Persian Gulf to form part of the Iraq-Iran border. It is a wide, swampy delta, but the marshlands were drained in the early 1990s so as to increase government control over the Arab Shiites who were the inhabitants. (The Columbia Encyclopaedia, 2008). . Shatt al Arab. Wikimedia Commons (Public Domain) 5. Foot slopes: Foot slopes also characterize the Tigris- Euphrates system. The main foot-slopes are at the Jabal Hamrin and also at the Zagros Mountains. 6. Mountain Ranges: Being in a mountainous region, it thus follows that there would likewise be various mountain regions in this system. The main ones are the Taurus and Zagros mountains. The Zagros Mountains are located on the East of the Tigris- Euphrates catchment and they appear as an abrupt wall hanging over the lowlands in the south below Baghdad and the main Zagros summits over 3000m in height. The Taurus complex is divided into four mountain ranges namely: in the western point, the Beydaglari mountain range whose highest peak is Mt. Kizlarsivrisi; in the south east the Bolkar mountain range whose highest peak is Mt. Medetsiz; in the central area the Aladaglar mountain range whose highest peak is Mt. Demirkazik; and in the north east, the Munzur mountain range, whose highest peak is Mt. Akbaba. The highest point in the Zagros Mountains is Zard Kuh while Mt. Demirkazik is the highest point in the Taurus Mountains. The mountain range ends at the Straits of Hormuz (Dean, 2004: 443). 7. Plateaus: The entire surrounding region, particularly in Turkey and Syria, is characterized by plateaus therefore it follows that the basin would likewise consist of this landform. Towards the west of the river valley, the land rises progressively into a plateau and this plateau progresses further towards Saudi Arabia, Jordan and then Syria. It has a peak height of 1000m which it attains is Iraq (World Wildlife, 2001). Towards the East of the Munzur and Anti Taurus Mountains, there is the Upper Euphrates high plateau and it has a height of about 800 to 1,500 m. In effect, the upper Euphrates has two branches that rise on the Armenian plateau thus expanding the reach of this plateau landform. B). CLIMATE TYPE AND RAINFALL DIFFERENTIATION OVER THE CATCHMENT AND HOW THIS RELATES TO GEOMORPHOLOGY To understand how landforms are formed in river basins, it is imperative that one is aware of the factors that affect geomorphological processes. In order to do so, an understanding of the river basin itself is crucial. The Tigris- Euphrates river catchment system is a vast system whereby in the upper courses the rivers lie 1,800 to 3,000 metres in altitude, rise to 370 metres in the middle courses at the foot of the Kurdish Escarpment and descend to 50 metres at which they empty onto the plain of central Iraq (Jassim and Goff, 2006: 253). In terms of location, the Euphrates River is found at (Latitude: 31° 0' 0 N, Longitude: 47° 25' 0 E) as shown in a world map while the Tigris River is to be found at (Latitude: 31° 0' 0 N, Longitude: 47° 25' 0 E). In totality, the river basin is about 1,200 feet wide and 30 feet deep (Bell, 2002). Evidently, The Tigris- Euphrates river catchment system is truly an expansive catchment system. As such, several aforementioned landforms characterize it basin. Such landforms, though characteristic of all catchments, vary from catchment to catchment depending on among several other factors, rainfall differentiation throughout the catchment area as well a the overall climate of the area. According to Conacher (2002), water movements cause the integration of catchments. In other words, water is responsible for pedological and geomorphic responses as it causes the movement of sediments in addition to the translocation of materials. In terms of rainfall, the Tigris- Euphrates catchment experiences varying precipitation rates. In the Tigris basin in South East Turkey, the height of the basin reaches maximum levels of 4,200 m and it is here that the majority river flow to the basin is generated with annual precipitation exceeding 1,000 mm (Beaumont, 2001). Most of the precipitation is experienced during winter from around October up until April. Consequently, most of the precipitation received is in the form of snow on the uplands causing the water to be constrained in a solid state on the mountain slopes until spring time and early summer when the temperatures rise. This greatly inhibits geomorphological processes such as erosion. Nevertheless, land shaping processes do occur during winter and are quite effective in shaping land forms. As ice gradually moves down a valley, it results in the plucking and abrasion of the underlying rock. Consequently, glacial flour (very fine sediments) are formed which is then subsequently transported and this process eventually causes the landscape to change. This is glacial erosion and occurs only during winter. This clearly shows that changes in climate over the basin result in differences in geomorphological process with glacial erosion occurring during winter whereas ordinary erosion occurs during the rest of the year. In fact, leading climatologists have begun to identify and explain the various existing modes of climatic variability that appear to be vital components of geomorphological processes. Of greatest geomorphological importance are climate oscillations both on an interannual basis and over century scales. The geomorphological impacts of such oscillations in climate include mass movement frequencies, alterations in stream flow and sediment yield as well as coastal erosion (Viles and Goudie, 2002). In the Tigris- Euphrates catchment come into play due to such climatic oscillations. The general climate in this basin is subtropical, arid and hot with mean temperatures exceeding 32 °C during the summer and below 10 °C during the winter together with great diurnal variations (Encyclopaedia Britannica Article, 2007). Evidently, great climate oscillations are experienced in this basin leading to varying geomorphological processes over the basin. This results in diversity with regards to the landforms that are formed on an annual basis as well as over the centuries whereby the former low temperatures of earlier centuries favoured glacial erosion as opposed to the rise in temperatures in the modern age that have caused a shift towards greater water movements and erosion. Changes in seasonal climate like summer wetness/ dryness and winter severity (Higgitt and Lee, 2001:12). C). THE DISTINCTION BETWEEN SEDIMENTARY AND EROSIONAL LANDSCAPES. Geomorphological processes differ according to the amount of rainfall as well as the prevailing climate. As such, different types of landscapes are formed. Two such different landscapes are sedimentary and erosional landscapes. These two types of landscapes vary in many ways. For one, sedimentary landscapes are caused due to the compression of the layered sediments while on erosional landscapes are formed due to the weathering effects of wind, temperature and water.  In addition, sedimentary landscapes are more aesthetically appealing than erosional landscapes. Undoubtedly, these landscapes have a very attractive scenic quality and this is mainly due to the arrangements of the layered strata. The strata lies in a horizontal position but is usually inclined by earth movements forming pleasing and marked contrasts characterized by graceful undulations, heavy massing of igneous rocks as well as the sharp pointed summits of the lavas (Old and Sold, 2009). The beds reveal a wide range of texture and tint to produce spectacles of enormous grandeur and beauty and. In fact, these landscapes appear to be the products of actual masonry as they have the tendency of cleaving vertically and in the process often form remarkable cliffs lying in unbroken beds through a great area. When many such properly-defined strata cleave vertically with one end sagging below another through faulting, the resulting effect is striking, scenic and varied. Several volcanic and granitic landscapes are multicoloured in places through accidental beds of sedimentary rock that furnish the landscape with the colours resulting from mineral dyes dissolved out of rocks (Old and Sold, 2009). Erosional landscapes on the other hand are often very dreary and drab, giving an appearance of infertility and want. This is because of the weathering of top layers and the revealing of underlying layers that can be quite unsightly and unattractive Thus, sedimentary landscapes are often beautiful and multi- coloured while erosional landscapes are drab and uninspiring. Another distinction is that erosional landscapes are relatively infertile when compared to sedimentary landscapes. This is due to the loss of fertile topsoil as a result of weathering and gullying. As a result, erosional landscapes are not favoured when it comes to agricultural pursuits. Most farmers, if given an option, would choose sedimentary landscapes over erosional landscapes. Apart from just farming, sedimentary landscapes are also useful for grazing and forestry purposes. Yet another distinction is that sedimentary landscapes are more prone to salinity than erosional landscapes. This is because water erosion has the positive effect of diluting the salinity wile sedimentation simply consolidates the amount of salinity of the soil. Furthermore, soil texture and the restriction of water flow at a change of slope common in sedimentary landscapes can contribute to the rise of water tables leading to a marked increase in salinity. This negatively impacts on agriculture, forestry and grazing. Furthermore, sedimentary landscapes are resistant to weathering due to the lack of cracks, faults or joints. Erosional landscapes, on the other hand, are highly susceptible to weathering (Grant, 2000). As a result, sedimentary landscapes are more permanent and long standing than erosional landscapes which take a short time to evolve. With each weathering action of water, wind or ice, an erosional landscape will undergo some for of transformation but sedimentary landscapes are highly resistant to external pressures and thus remain relatively unchanged for longer period of time. D). THE MAIN MAN-MADE FEATURES THAT HAVE ALTERED THE GEOMORPHOLOGY OF THE TIGRIS- EUPHRATES CATCHMENT. The Tigris- Euphrates catchment has been in existence for several years and has inevitably undergone various changes to its landscape. Human activity has been the greatest factor towards its drastic transformation over the centuries and the state it was back then has dramatically changed to something completely different than its original state. Since many people depend on the catchment for survival, they have exploited and transformed it to suit their needs. Several man-made features dot the landscape as a result and these include: Irrigation Canals: most people in this are grow crops that are dependent on irrigation due to the insufficient and irregular rainfall experienced. (Encyclopaedia Britannica Article, 2007). Extremely intensive irrigation has been used for several centuries and has led to the alteration of the basin and surrounding areas as well as the gradual damage of the soil through salinization (Campbell, 1999). In use are three different types of canals. These types are controlled canals, uncontrolled canals and raised concrete flumes that use pumps. Drainage systems: Since river water contains salt as opposed to rain water, the irrigated fields in the area are susceptible to becoming waterlogged with salty water that are detrimental to the growth of crops. To counter this, people construct drainage systems to remove the salt and excess water and in the process, contribute to the further alteration of the catchment. Dams: Various engineering projects have been in initiated in the Tigris- Euphrates catchment to enhance better water management for residents. Dams are a product of these projects and are numerous in the catchment. To its great detriment, the Tigris-Euphrates catchment has for the past thirty years seen the construction of more than 60 engineering projects which saw the diminishing of seasonal floods and natural flow. Examples of major dams were constructed in Tabqa, Haditha, Keban, Karakaya, Hamrin, Mosul, and Ataturk. (Jones, 2002). While these dams have been important for catering to the fresh water needs of the people, the Tigris- Euphrates environment has been adversely affected in the process. CONCLUSION At the onset of this discussion, the objective was to analyze the various landform types that are contained within the Tigris- Euphrates system; the geomorphological processes that characterize it; as well as the man made features that have altered its landscape among other things. During the course of the discussion, landforms such as gorges, plateaus; terraces, among many others were identified as being prominent within the catchment. Factors such as rainfall differentiation and climate wee discovered to have a major impact on the geomorphology of the area. Thereafter, man- made features such as irrigation canals and dams were identified as factors responsible for the transformation of the catchment. These discoveries were crucial in shedding light concerning this great catchment system and further geomorphological studies into this area are required to ensure that it remains prominent and viable; both for the present time and for the future generations as well. REFERENCES Al- Uzaym. 2009. Encyclopaedia Britannica. Encyclopaedia Britannica Online. Accessed on the 25th of July 25, 2009 http://www.britannica.com/EBchecked/topic/621016/Al-Uzaym Beaumont, Peter. 2001. Restructuring of Water Usage in the Tigris- Euphrates Basin: The Impact of Modern Water Management Policies. University of Wales, Lampeter. Accessed on the 24th of July 25, 2009 from http://environment.research.yale.edu/documents/downloads/0-9/103beaumont.pdf Bell, James W. 2002. Ancient Sumeria: The Tigris River. Accessed on the 25th of July 25, 2009 http://www.jameswbell.com/a008thetigrisriver.html Campbell, Robert Wellman. 1999. Irrigating in Mesopotamia. Earth shots: Satellite Images of Environmental Change. U.S. Geological Survey. Accessed on the 24th of July 25, 2009 from http://earthshots.usgs.gov/Iraq/Iraq Conacher, Arthur. A Role for Geomorphology in Integrated Catchment Management. 2002. Australian Geographical Studies Vol 40 No: 2 Pp: 179-195. Accessed on the 24th of July 25, 2009 from http://dx.doi.org/10.1111/1467-8470.00173 Dean, Lucy. 2004. The Middle East and North Africa. Taylor & Francis Group: London. Accessed on the 25th of July 25, 2009 from http://books.google.co.ke/books?id=pP315Mw3S9EC&pg=PA443&lpg=PA443&dq=PHYSICAL+FEATURES+IN+THE+TIGRIS+EUPHRATES+SYSTEM&source=bl&ots=_3esa5kx3M&sig=NLS6kKbyHUNqj3Gcl0_Cqkk8Fvs&hl=en&ei=RJ1lSv6SFc7I-QbPmMxe&sa=X&oi=book_result&ct=result&resnum=3 Demir, Tuncer. 2007. Terrace staircases of the River Euphrates in southeast Turkey, northern Syria and western Iraq: evidence for regional surface uplift. Science Direct. Quaternary Science Reviews, 26 (22-24), pp. 2844-2863. Accessed on the 25th of July 25, 2009 from http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VBC-4R05VC2-4&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=963484425&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=237813a2d0548614793d5f94e61ac762 Encyclopaedia Britannica Article. 2007. Tigris-Euphrates river system. Accessed on the 23rd of July 25, 2009 from http://www.enwiki.net/wiki/eb/2251 Grant, C. 2000. Rock Landforms of Australia & NZ. Accessed on the 24th of July 25, 2009 from http://www.vnc.qld.edu.au/enviro/landform/landf-sg.htm Higgitt, David L and E. Mark Lee. 2001. Geomorphological processes and landscape change. Oxford: Wiley- Blackwell.  Jassim, Saad Z and Goff, Jeremy C. 2006. Geology of Iraq. Dolin Publishers: Czech Republic. Jones, C. 2002. Hydrologic impacts of engineering projects on the Tigris-Euphrates system and its marshlands. Department of Geosciences, Western Michigan University. Accessed on the 24th of July 25, 2009 from http://cat.inist.fr/?aModele=afficheN&cpsidt=20283261 Kaya, Ibrahim. 1998. The Euphrates-Tigris basin: An overview and opportunities for cooperation under international law. Arid Lands Newsletter. Accessed on the 20th of July, 2009 from http://ag.arizona.edu/OALS/ALN/aln44/kaya.html Lesschen, Jan Peter. 2002. ISRIC. Major Landforms in Alluvial Landforms. Accessed on the 20th of July, 2009 from http://www.isric.org/ISRIC/webdocs/docs/major_soils_of_the_world/set4/alluvial.pdf Old and Sold. 2009. On Sedimentary Rock In Scenery. Accessed on the 24th of July 25, 2009 from http://www.oldandsold.com/articles14/national-parks-44.shtml Springer Berlin. 2007. Late Cenozoic surface uplift, basaltic volcanism, and incision by the River Tigris around Diyarbakır, SE Turkey. International Journal of Earth Sciences. Vol 98, Number 3. The Columbia Encyclopaedia, Sixth Edition. 2008. Encyclopedia.com. Accessed on the 25th of July 25, 2009 from http://www.encyclopedia.com Viles, H. A. and Goudie, A. S. 2002. Interannual, Decadal and Multidecadal Scale Climatic Variability and Geomorphology. Accessed on the 24th of July 25, 2009 from http://linkinghub.elsevier.com/retrieve/pii/S0012825202001137 World Wildlife. 2001. Eastern Anatolian deciduous forests. Accessed on the 24th of July 25, 2009 from http://www.worldwildlife.org/wildworld/profiles/terrestrial/pa/pa0420_full.html Read More