Tigris & Euphrates Basin

Background

Beginning in 1954 the Turkish government surveyed 53 kilometres (33 miles) of the Tigris river downstream of Diyarbakır with the aim of identifying suitable locations for a hydroelectric power plant at an elevation below 550 metres (1,800 ft). Turkey's Electric Power Resources Survey and Development Administration (EIE) included 10 potential sites in its 1971 Tigris River Pre-Investigation Report. By 1975, the EIE had completed a technical and economic evaluation of the sites. Ilısu was selected as the preferred site for geological reasons. A feasibility study and final design by international consultants (1980–82) resulted in a recommendation to construct both the Ilısu Dam and the Cizre Dam downstream.

Construction

As part of early and ongoing construction, 52 km (32 mi) of roads are subject to raising and repairing work. A 110 m (361 ft) long temporary bridge was constructed upstream of the dam site which is supported by 30 sections of steel pipe. Additionally, a 250 m (820 ft) permanent steel-girder bridge with concrete supports was constructed just downstream of the dam. Construction of new Ilısu and Koçtepe villages were underway as well as the relocation of major portions of Hasankeyf. Excavations for the main body of the dam began in May 2011 and the first loads of fill were laid in January 2012. Diversion of the Tigris River began during a ceremony on 29 August 2012. As of April 2014, the project is 60% complete while the resettlement of Hasankeyf is 73% complete.

Design

The Ilısu Dam will be a 135 m (443 ft) high and 1,820 m (5,971 ft) wide rock-fill embankment dam with a structural volume of 43,900,000 m3 (35,590 acre⋅ft). It will be 15 m (49 ft) wide at its crest and 610 m (2,001 ft) wide at its base. The dam will have an overflow spillway on its right bank which will be controlled by eight radial gates which will pour into four chutes before the water reaches a plunge pool. Its power station will be above ground and will contain 6 x 200 MW Francis turbine-generators with an expected annual generation of 3,833 GWh and gross hydraulic head of 122.6 m (402 ft).

History

To ensure as many of the archeological sites were inspected before being submerged under the lake that would form behind the dam, the Iraqi government invited several foreign delegations to participate. This rescue operation included the British Archaeological Expedition to Iraq as a prominent participant. In 1985, one of their sites, Tell Deir Situn garnered an Assyrian fibula, some Hellenic oil lamps, and a Seleucid coin of Alexander Balas.

In 2010, following a massive drought, the ruins of an ancient palace were discovered in the reservoir. The palace, which is approximately 3,400 years old, is believed to have belonged to the Mitanni. The first excavation occurred in 2019 by a joint Kurdish-German team.

Project history

In 1927, when Syria was a French mandate, it was proposed to build a dam in the Euphrates near the Syria–Turkey border. After Syria became independent in 1946, the feasibility of the project was studied and shelved. In 1957, the Syrian government reached an agreement with the Soviet Union to build a dam in the Euphrates. In 1960, as part of the United Arab Republic, Syria signed an agreement with West Germany for a financing loan. In 1965, after Syria left the UAR, a new agreement was reached with the Soviet Union. A special government department was created to oversee the construction. In the early 1960s Swedish geomorphologist Åke Sundborg worked as an advisor on the dam project with the task of estimating the amount and fate of sediment entering the dam.