Open Eng. 2015; 5:465–477 Research Article Open Access Nadhir Al-Ansari*, Ammar A. Ali, Qusay Al-Suhail, and Sven Knutsson Flow of River Tigris and its Effect on the Bed Sediment within Baghdad, Iraq DOI 10.1515/eng-2015-0054 Received Jan 22, 2015; accepted Oct 08, 2015 1 Introduction Abstract: River Tigris is a major river in Iraq. Sediment at Iraq is part of the Middle East and North Africa (MENA) the bed of the river within a reach of about 18 km from region. It covers an area of 433,970 km2 and is populated the center of Baghdad upstream was investigated. Sixty by about 32 million inhabitants (Figure 1). Baghdad City, five cross sections were surveyed, and 46 sediment sam- the capital of Iraq, is bisected into two areas from the north ples were collected and analyzed. It was noticed that fine to the southeast by the Tigris River for a distance of 60 km, sand was dominant in the bed (90.74%). The average me- 50 km of which are located within the urban areas, and the dian size within the reach was 2.49 phi (0.177 mm), while rest is in rural parts (Figure 2). the mean size was 2.58 phi (0.16 mm). In addition, the Within Baghdad, the Tigris River has a single channel sediments were moderately sorted, fine skewed and lep- characterized by compound meanders. Thirteen bridges tokurtic. The size of the bed sediment decreased relative have been installed along this reach to join the western to previous investigations due to the construction of the and eastern parts of the city. A series of small meanders Adhaim dam on tributary, which used to be the main sedi- are noticed within the northern part of the river, which is ment supplier to the Tigris River before entering Baghdad. located upstream from the center of Baghdad (Sarai Bagh- Furthermore, the discharge of the Tigris River for the pe- dad), and the banks of the river are protected by stones and riod 1983–2013 (715 m3/s) decreased by about 40% and cement mortar (Figure 2) [1, 2]. The southern part of the 30% since 1983 when compared with the periods 1931–1956 river is characterized by large meanders and about half of (1208 m3/s) and 1956–1980 (1015 m3/s), respectively, due this river portion has it banks protected [1, 2]. to climate change and construction of dams upstream from Tigris River has 10 islands and 17 side and point bars Baghdad. This has decreased the capacity and the compe- along its reach inside Baghdad City (Figure 2) [1, 2]. These tence of the river. The bed elevation has increased com- islands and bars are affecting the hydraulic performance pared to previous surveys. It was noticed that dredging op- of the river; this includes changing of the river cross sec- erations and obstructions (e.g. fallen bridges and islands) tions, which reduces the flooding capacity of the river, have disturbed the flow of the river and sediment charac- and decreasing water depth at the intakes of water pump- teristics in several sites. ing stations, approaching the river bed from the intake mouths. In addition, there is the impossibility of navi- Keywords: Bed sediment; Regulated Flow; Tigris River; gation along the whole reach and limitation to discrete Baghdad; Iraq zones, and the threating of the banks’ protection stabil- ity at some locations due to deep eroding incisions in the river bed. Furthermore, these obstacles are also affecting *Corresponding Author: Nadhir Al-Ansari: Department of Civil, the environment and aesthetic characteristics, such as in- Environmental and Natural Resources Engineering, Lulea University creasing the turbidity, growing of reeds, water hyacinth of Technology, Lulea, Sweden; Email: [email protected] and ceratophyllum demersum at stagnant locations, as Ammar A. Ali: Department of Civil, Environmental and Natural well as the disfiguration of aesthetic view over the river Resources Engineering, Lulea University of Technology, Lulea, Swe- and its banks [1, 2]. This has led Iraqi Ministry of Water Re- den; Email: [email protected]; Department of Water Resources, sources [3] to dredge parts of the river to attempt to over- College of Engineering, Baghdad University, Baghdad, Iraq; Email: [email protected] come these impacts [2]. Qusay Al-Suhail: Department of Earth Sciences, College of Science, Three surveys have been conducted along Tigris River Baghdad University, Baghdad, Iraq; Email: [email protected] in the city of Baghdad. The first was conducted in 1976 by Sven Knutsson: Department of Civil, Environmental and Natural Geohydraulique [4], followed by University of Technology Resources Engineering, Lulea University of Technology, Lulea, Swe- in 1991 [5], and finally by IMoWR in 2008 [3]. It is notewor- den; Email: [email protected] © 2015 N. Al-Ansari et al., published by De Gruyter Open. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License. 466 Ë N. Al-Ansari et al. FigureFigure 1. 1: Map of of Iraq Iraq with Figurewith focusing focusing on 1. Baghdad Map on CityofBaghdad [6,Iraq 7]. with City focusing[6, 7] on Baghdad City [6, 7] thy to mention that none of these surveys studied the sed- N iment characteristics of theN river in details. In this research, sediment samples from the bed of the Al-Muthana Bridge River Tigris at a reach extending from the center of Bagh- Al-Muthana Bridge dad at Sarai Baghdad gauging station to about Muthana Bridge in the north were been analyzed for their charac- Sarai Baghdad teristics. The breadth of the river within this reach ranges Saraifrom Baghdad 150 to 360 m. 2 River Tigris The catchment area of the river is 473,103 km2 and is dis- tributed between Turkey, Syria, Iran and Iraq (Table 1) [8– 11]. River Tigris enters Iraq four kilometers north of Diyala Fieshkhabur, near Zakho city (Figure 3). The Tigris is River joined by its first tributary inside Iraq, which is known as Khabur River. This tributary is 100 km long; its catchment area is 6,268 km2 withDiyala an average discharge of 68 m3/s. The Tigris River runs southRiver for about 188 km in a hilly area to reach Mosul city. At Mosul the average, maxi- 3 mum and minimum discharges of the river are 668 m /s, Figure 2. River Tigris within Baghdad City (islands and sandbars border7,740 by m 3red)/s (on [2]. 2/5/1972) and 85 m3/s (in October, 1935), re- Figure 2: River Tigris within Baghdad City (islands and sandbars border by red) [2]. spectively. The elevation of the channel bed is 225 m above sea level [8, 9, 11]. Figure 2. River Tigris within Baghdad City (islands and sandbars border by red) [2]. Bed sediment of R.Tigris at Baghdad Ë 467 Iraq–Turkey Border Khabour ure 3). Its total length is 437 km with a mean discharge of Al Khazir Al 3 Tigris River 450 m /s. It supplies 28.7% of the Tigris water [8, 9, 11]. Duhok The Tigris River runs south and the Lesser Zab tribu- Mosul tary joins the river Tigris (Figure 3). The total catchment area of this tributary is 22,250 km2. The total length of the Greater Zab tributary is 456 km with a mean discharge of 227 m3/s. Mosul About 30 km downstream of this confluence the Tigris River crosses Fatha gorge. The river Tigris mean, maximum Sharqat Lesser Zab River 3 Dokan Dibs and minimum discharges at Fatha gorge are 1,349 m /s, Fatha/Baji 16,380 m3/s (on 3/4/1969) and 200 m3/s (in October 1930), Flood Escape Channel Iraq –Iran Border Samarra respectively [8, 9, 11]. Tharthar Al Adhaim Adhaim River Lake River Tigris The Adhaim tributary joins the Tigris 68 km south of Tharthar Main Regulator Sammara Barrage (Figure 3). The tributary drains an area of 13,000 km2 lying within Iraq. Its length is 330 km. The Baghdad 3 Diyala River Hemrin Derbend-i mean daily discharge is 25.5 m /s. The banks of the river Khan Diyala Tigris south of its confluence with the Adhaim tributary are Al-Gharaf Iraq –Iran Border below the maximum flood peak level by 3 m from the left, Dujaila and by 1.8 m from the right [8, 9, 11]. Kut Further to the south, the river reaches Baghdad. At Kut Showaija Pond Baghdad, the mean, maximum and minimum discharges Tigris River Tigris are 1,140 m3/s, 7,640 m3/s (on 12/2/1941) and 163 m3/s (in Chabab October 1955), respectively. The slope of the channel is very Sanaf low, i.e. 6.9 cm/km. It is noteworthy to mention that since Pond 1990 the flow of the River Tigris at Baghdad is completely controlled by the regulating scheme at Sammara and the Karkah River Amarah Adhaim dam. Amarah About 31 km south of Baghdad, the last main tributary Haweza Marsh “Diyala” joins the Tigris (Figure 3). Diyala’s drainage basin Iraq –Iran Border 2 3 Kasara is 31,896 km with a mean daily discharge of 182 m /s [8, Euphrates River Qurna City Al-Sweeb Dam 9, 11]. Barrage Downstream of the confluence of the Tigris–Diyala Basra Natural River Karoon River Channel or wady rivers, the Tigris channel is characterized by its large num- Shat Al-Arab Border ber of meanders. In addition, the river discharge steadily Gulf of Arabia decreases downstream due to losses. These losses include Figure 3. Schematic diagram of Tigris River and its tributaries hydrologicalevaporation, scheme [12] infiltration, and mainly water withdrawal Figure 3: Schematic diagram of Tigris River and its tributaries hydro- through irrigation canals.