Shared Water Resources in Turkey

Turkey has five transboundary river basins. From north to south, they are the Çoruh River Basin, Aras and Kura River Basin, Euphrates-Tigris River Basin, Asi (Orontes) River Basin, and in the west, the Meriç (Maritza) River Basin. These basins occupy an important position in Turkey’s international relations because of their transboundary characteristics. Just over 36% of Turkey’s water potential is composed of transboundary waters.[1]

Euphrates-Tigris River Basin

The Euphrates-Tigris River Basin is among the most important river basins in Turkey and the Middle East. The combined average annual discharge of the Euphrates and Tigris rivers is 84 BCM, which is comparable to the average annual flow of the River Nile. The Euphrates provides 90% of its water from Turkey, with an average annual flow of 32 BCM. The remaining 10% comes from Syria. The average annual flow of the Tigris is 52 BCM, with the average annual flow of the Tigris at the Cizre gauging station near Turkey’s border with Iraq is 16.2 BCM.

The Euphrates-Tigris River Basin is a vital source of energy, food and drinking water for Turkey, Syria and Iraq, which are the main riparians to the basin. Turkey considers the Euphrates-Tigris River Basin as a single basin whereas Syria and Iraq treat the two rivers separately. The riparians have been working on developing the basin waters since the 1950s.[2] In this period, the DSİ built the Keban, Karakaya and Atatürk dams respectively on the Euphrates. Several dam projects were then constructed in Syria on the Euphrates and Asi (Orontes) rivers, two of the country’s most important water resources. Tabqa, Syria’s largest dam, was built in 1968.[3]

During the filling of the Keban and Tabqa dams and the construction of the Atatürk Dam, a dispute broke out between Turkey, Syria and Iraq. Iraq reacted strongly to Syria reducing the water flow into Iraq. While basin states maintained their water projects, Turkey and Iraq established a Joint Technical Committee (JTC) in 1981 to use waters effectively, wisely and fairly. Syria participated in the JTC in 1983. Negotiations were suspended after the 16th meeting of JTC in 1992. Nevertheless, tripartite meetings were held again in 2007 at a technical and political level. Turkey agreed to release 500 m3 of water per second until final agreement among the three riparian countries as stipulated in the protocol signed between Turkey and Syria in 1987. Turkey has fulfilled this commitment for 35 years.[4]

The Adana Accord signed between Turkey and Syria in 1998 provided a basis for cooperation in many fields including tourism and trade. In this context, a cooperation protocol concerning water resources was signed in 2001 between the GAP Regional Development Administration and the General Organization of Land Development.[5]

Turkey signed a memorandum of understanding (MoU) with Syria in 2009. The agreement included monitoring of water resources, joint projects and protocols, and climate change mitigation. One of the protocols between the countries envisages the construction of the joint Friendship Dam on the Asi River. Construction began in February 2011, but the Syrian uprising that began the following month has set the project back.[6]

On 15 October 2009, Turkey and Iraq signed 48 MoUs, including one related to water, with explicit references to water resources management, irrigation system upgrades, and hydrological and meteorological data exchange. Given the demand pressures and increasing climate conditions, the water-related MoU also recognized the necessity for an urgent evaluation of water supplies. Following these measures, Turkey and Iraq organized the second meeting of the High-level Strategic Cooperation Council in 2014, as a result of which the two countries updated the 2009 MoU, which entered into force in 2021.[7]

Asi (Orontes) River Basin

Unlike the Euphrates and Tigris, Turkey is a downstream country on the Asi River. The Asi originates in the Bekaa Valley in Lebanon and enters Syria after about 40 km. There is no definitive information either on the length of the river or its flow. Different sources quote the length of the river as anything from 248 km to 571 km, while annual flow varies from 1.2 BCM, according to Turkish data, to 2,751 BCM according to Syrian data.[8]

Çoruh River Basin

The overall length of this river is 431 km. After it leaves Turkey, it flows through Georgia for 21 km before emptying into the Black Sea at Batum. The river’s water potential is 6.4 BCM. Turkey has planned ten dams and hydroelectric stations on the river, which will generate 10.5 billion kWh annually. Once completed, these projects are expected to provide 6% of Turkey’s overall hydroelectric potential.[9]

Aras and Kura River Basin

The Aras and Kura rivers originate in Turkey. The Aras provides 45% of the total water flow of the basin while the remaining 55% is provided by the Kura. The Kura flows for 210 km in Turkey before crossing into Georgia and flowing another 390 km there. The Kura River Basin, with a length of 1,364 km, covers an area of 88,000 km2. The Aras flows for approximately 300 km in Turkey and then forms the border between Turkey, Armenia, Azerbaijan and Iran. On the border between Azerbaijan and Iran, the Aras joins the Kura, and they reach the Caspian Sea together in Azerbaijan. The estimated average flow of the Aras is 3.3 BCM/yr. Agriculture and animal husbandry are the main economic activities in the Turkish part of the basin.[10]

Meriç (Maritza) River Basin

The Meriç River originates in the Rila Mountains in Bulgaria. According to the Meriç Bridge gauging station in Turkey, the average flow of the river, whose basin is 53,000 km2, is 147 m3/s. The river flows for 320 km through Bulgaria then runs for 240 km along the border between Turkey and Greece before emptying into the Aegean Sea. Besides its main reach, the Meriç River merges with four other reaches. These are Arda, Tunca, Kızıldeli Su (Erythropotamos) and Ergene. The main problems facing the Meriç River Basin are flooding and pollution, although during the summer months it can also experience droughts. Turkey, Greece and Bulgaria have signed separate agreements with each other to improve flood protection. However, there is no agreement related to the Meriç River waters among these countries.[11]