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==Characteristics of the dam and the reservoir== |
==Characteristics of the dam and the reservoir== |
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The Tabqa dam is located on a spot where rocky outcrops on each side of the Euphrates Valley are less than 5 km apart. The |
The Tabqa dam is located on a spot where rocky outcrops on each side of the Euphrates Valley are less than 5 km apart. The dam is an earth-fill dam that is 4,500 m long, 60 m high from the riverbed (307 m above sea-level), 512 m wide at its base and 19 m at the top.<ref name=bourgey149>{{harvnb|Bourgey|1974|p=349}}</ref> The hydroelectric power station is located on the southern end of the dam and contains eight [[Kaplan turbine|Kaplan turbines]]. The turbines' rotation speed is 125 rounds/minute, and they can potentially generate 103 MW each.<ref>{{harvnb|Bourgey|1974|p=351}}</ref> Lake Assad behind the dam is 80 km long and on average 8 km wide.<ref name=collelo></ref> The reservoir can potentially hold 11.7 km³ of water, at which size its surface area would be 610 km².<ref name=altinbilek21></ref> Annual [[evaporation]] is 1.3 km³ due to the high average summer temperature in northern Syria.<ref name=Elhadj>{{harvnb|Elhadj|2008}}</ref> This is high compared to reservoirs upstream from Lake Assad. For example, the evaporation at [[Keban Dam|Lake Keban]] is 0.48 km³/year at roughly the same surface area.<ref name=kalpakian108></ref> |
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Neither the Tabqa Dam nor Lake Assad are currently used to their full economic potential. Although the lake can potentially hold 11.7 km³, actual capacity is 9.6 km³ with a surface area of 447 km².<ref>{{harvnb|Jones|Sultan|Yan|Milewski|2008|p=62}}</ref> The proposed irrigation scheme suffered from a number of problems, including the high [[gypsum]] content in the reclaimed soils around Lake Assad, [[salinization|soil salinization]], and the collapse of canals that distributed the water from Lake Assad. As a result, only 60,000 ha were irrigated from Lake Assad in 1984.<ref name=collelo></ref> In 2000, the irrigated surface had risen to 124,000 ha, which is 19% of the projected 640,000 ha.<ref name=Elhadj></ref> Due to lower than expected water flow from Turkey, as well as lack of maintenance, the dam generates only 150 MW instead of 800 MW.<ref name=shapland110></ref> Through a pipeline between Lake Assad and Aleppo, 0.8 km³ of drinking water is provided to the city each year.<ref name=shapland110></ref> The lake currently also supports a modest fishing industry.<ref>{{harvnb|Krouma|2006}}</ref> |
Neither the Tabqa Dam nor Lake Assad are currently used to their full economic potential. Although the lake can potentially hold 11.7 km³, actual capacity is 9.6 km³ with a surface area of 447 km².<ref>{{harvnb|Jones|Sultan|Yan|Milewski|2008|p=62}}</ref> The proposed irrigation scheme suffered from a number of problems, including the high [[gypsum]] content in the reclaimed soils around Lake Assad, [[salinization|soil salinization]], and the collapse of canals that distributed the water from Lake Assad. As a result, only 60,000 ha were irrigated from Lake Assad in 1984.<ref name=collelo></ref> In 2000, the irrigated surface had risen to 124,000 ha, which is 19% of the projected 640,000 ha.<ref name=Elhadj></ref> Due to lower than expected water flow from Turkey, as well as lack of maintenance, the dam generates only 150 MW instead of 800 MW.<ref name=shapland110></ref> Through a pipeline between Lake Assad and Aleppo, 0.8 km³ of drinking water is provided to the city each year.<ref name=shapland110></ref> The lake currently also supports a modest fishing industry.<ref>{{harvnb|Krouma|2006}}</ref> |
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The Tabqa Dam, or al-Thawra Dam as it is also named (Arabic: سد الثورة, literally the dam of the revolution), is an earth-fill dam on the Euphrates, located 40 km upstream from the city of Ar-RaqqahinAr-Raqqah Governorate, Syria. The dam is 60 m high and 4.5 km long and is the largest dam in Syria.[1] Its construction led to the creation of Lake Assad, Syria's largest water reservoir. The dam was constructed between 1968 and 1973 with help from the Soviet Union. At the same time, an international effort was made to excavate and document as many archaeological remains in the area of the future lake before they would be flooded by the rising water. When the flow of the Euphrates was reduced in 1975 to fill the lake behind the dam, a dispute broke out between Syria and Iraq that was settled by intervention from Saudi Arabia and the Soviet Union.[2] The dam was originally built to generate hydroelectric power, as well as irrigate lands on both sides of the Euphrates. The dam has not reached its full potential in either of these objectives.[3]
Originally, the Tabqa Dam was conceived as a dual-purpose dam. The dam would include a hydroelectric power station with eight turbines capable of producing 832 MW in total, and would irrigate an area of 640,000 ha on both sides of the Euphrates.[3][4] Construction of the dam lasted between 1968 and 1973, while the accompanying power station was finished in 1977, and was partially financed by a loan from the Soviet Union. The Soviet Union also provided technical expertise.[5] Total cost of the dam was US$340 million of which US$100 million in the form of a loan by the Soviet Union.[4] During construction, up to 12 thousand Syrians and 900 Russian technicians worked on the dam.[6] They were housed in the greatly expanded town near the construction site, which was subsequently renamed Al-Thawra.[1] To facilitate this project, as well as the construction of irrigation works on the Khabur, the national railway system (Chemins de Fer Syriens) was extended from Aleppo to the dam, Ar-Raqqa, Deir ez-Zor, and eventually Al-Qamishli.[7]
In 1975, Syria started to fill the lake behind the dam by reducing the flow of the Euphrates. Slightly earlier, Turkey had started filling the reservoir of the newly construceted Keban Dam, and at the same time the area was also hit by significant drought.[8] As a result, Iraq received significantly less water from the Euphrates than normal, and complained that annual Euphrates flow had dropped from 15.3 km³ in 1973 to 9.4 km³ in 1975.[9][10] Iraq asked the Arab League to intervene but Syria argued that it received less water from Turkey as well and refused to cooperate.[11] As a result, tensions rose and Iraq and Syria sent troops to their shared border.[2] Iraq also threatened to bomb the Tabqa Dam.[2][12] Eventually, an agreement was reached in 1975 by mediation of Saudi Arabia and the Soviet Union whereby Syria immediately increased the flow from the dam and reportedly henceforth agreed to let 60% of the Euphrates water flow into Iraq.[2][11] In 1987, Turkey, Syria and Iraq signed an agreement by which was Turkey was committed to maintain an average Euphrates flow of 500 m³/s into Syria, which translates into 16 km³ of water per year.[13]
The upper part of the Syrian Euphrates valley has been intensively occupied at least since the Late Natufian period (10,800-9500 BC).[14][15] Nineteenth- and early twentieth century European travellers had already noted the presence of numerous archaeological sites in the area that would be flooded by the new reservoir.[16] In order to preserve or at least document as many of these remains as possible, an extensive archaeological rescue programme was initiated.[17]
Between 1963 and 1965, archaeological sites and remains were located with the help of aerial photographs, and a ground survey was carried out as well to determine the periods that were present at each site.[18] Between 1965 and 1970, foreign archaeological missions carried out systematic excavations at the sites of Mureybet (United States), Tell Qannas (Belgium), Habuba Kabira, Mumbaqa (Germany), Selenkahiye (Netherlands), and Emar (France). With help from UNESCO, two minarets at Mureybet and Meskene were photogrammetrically measured, and a protective glacis was built around the castle Qal'at Ja'bar. The castle was located on a hilltop that would not be flooded, but the lake would turn it in an island.[19] The castle is now connected to the shore by a causeway.
In 1971, with support from UNESCO, Syria appealed to the international community to participate in the efforts to salvage as many archaeological remains as possible before the area would disappear under the rising water of Lake Assad. For this purpose, the Syrian antiquities law was modified so that foreign missions had the right to claim a part of the artefacts that were found during excavation. As a result, between 1971 and 1974, numerous excavations were carried out in the Lake Assad area by Syrian as well as foreign missions. The excavated sites are: Tell al-'Abd, Tell Fray, Dibsi Faraj 'Anab al-Safinah, Tell Sheikh Hassan, Qal'at Ja'bar (Syria), Mureybet, Emar (France), Tell al-Hajj (Switzerland), Tell Ta'as, Hadidi, Jebel 'Aruda, Selenkahiye (Netherlands), Abu Hureyra, Tell es-Sweyhat (Great Britain), Tell Fray, Shams ed-Din-Tannira Dibsi Faraj (United States), Tell Fray (Italy) and Tell Roumeila (Japan). In addition, the minarets of Mureybet and Meskene were moved to higher locations, and Qal'at Ja'bar was further reinforced and restored.[20]
After the completion of the Tabqa Dam, Syria built two more dams in the Euphrates, both of which were functionally related to the Tabqa Dam. The Baath Dam, located 18 km downstream from the Tabqa Dam, was completed in 1988 and functions as a floodwater control to manage the irregular output of the Tabqa Dam and as a hydroelectric power station. The Tishreen Dam, which functions primarily as a hydroelectric power station, has been constructed 80 km south from the Syro-Turkish border and filling of the reservoir started in 1999.[21] Its construction was partly motivated by the disappointing performance of the Tabqa Dam.[22] The implementation of a fourth dam between Ar-Raqqa and Deir ez-Zor has recently been initiated with an appeal to archaeologists to excavate sites that will be flooded by the new reservoir.[23]
The Tabqa dam is located on a spot where rocky outcrops on each side of the Euphrates Valley are less than 5 km apart. The dam is an earth-fill dam that is 4,500 m long, 60 m high from the riverbed (307 m above sea-level), 512 m wide at its base and 19 m at the top.[24] The hydroelectric power station is located on the southern end of the dam and contains eight Kaplan turbines. The turbines' rotation speed is 125 rounds/minute, and they can potentially generate 103 MW each.[25] Lake Assad behind the dam is 80 km long and on average 8 km wide.[22] The reservoir can potentially hold 11.7 km³ of water, at which size its surface area would be 610 km².[21] Annual evaporation is 1.3 km³ due to the high average summer temperature in northern Syria.[26] This is high compared to reservoirs upstream from Lake Assad. For example, the evaporation at Lake Keban is 0.48 km³/year at roughly the same surface area.[8]
Neither the Tabqa Dam nor Lake Assad are currently used to their full economic potential. Although the lake can potentially hold 11.7 km³, actual capacity is 9.6 km³ with a surface area of 447 km².[27] The proposed irrigation scheme suffered from a number of problems, including the high gypsum content in the reclaimed soils around Lake Assad, soil salinization, and the collapse of canals that distributed the water from Lake Assad. As a result, only 60,000 ha were irrigated from Lake Assad in 1984.[22] In 2000, the irrigated surface had risen to 124,000 ha, which is 19% of the projected 640,000 ha.[26] Due to lower than expected water flow from Turkey, as well as lack of maintenance, the dam generates only 150 MW instead of 800 MW.[3] Through a pipeline between Lake Assad and Aleppo, 0.8 km³ of drinking water is provided to the city each year.[3] The lake currently also supports a modest fishing industry.[28]
Research indicates that the salinity of the Euphrates water in Iraq has increased considerably since the nearly simultaneous construction of the Keban Dam in Turkey and the Tabqa Dam in Syria. This increase can, among other things, be related to the lower discharge of the Euphrates as a result of the construction of the Keban Dam and the dams of the Southeastern Anatolia Project (GAP) in Turkey, and to a lesser degree of the Tabqa Dam in Syria. Highly saline water is less useful for domestic and irrigation purposes.[29]
The western shore of the lake has developed into an important marshland area with reeds. On the southeastern shore, some areas have been reforested with evergreen trees including the Aleppo pine and the Euphrates poplar. Lake Assad is an important wintering location for migratory birds and the government has recently undertaken measures to protect small areas along the shores of Lake Assad from hunters by downgrading access roads. The island of Jazirat al-Thawra has been designated a nature reserve.[30]
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