A turnkey contract for the construction of the 670-MW Deriner dam on the Coruh river in the northeast, was signed by a consortium led by Switzerland's ABB Power Generation on 4 November. The dam is the first and largest of a series of hydroelectric dams planned in the Coruh river basin by the client State Hydraulic Works (DSI - MEED 12:9:97).

The consortium also includes Sulzer, Hydro Vevey and Stucky, all of Switzerland, Russia's Technostroyexport and the local ERG. Financing valued at about $350 million will be arranged by the Swiss Banking Corporation.

The $711 million project, which will take about seven years to build, is also the largest project signed up by DSI within the last

10 years, its sources say. Work is expected to start by the end of the year or early 1998 after the contract is registered with the court of accounts, say the sources. The dam will be a double-curvature, concrete belt structure impounding a reservoir of about 3.5 million cubic metres of water.

DSI also expects to start negotiations in early 1998 after the receipt of technical tenders for another four large dams which are part of a series planned for the Coruh basin. DSI hopes to finalise the negotiations in about a year for construction to start in early 1999. The dams and their consortia are:

the 540-MW Yusufeli dam and the 332-MW Artvin dam, being negotiated by a consortium led by France's Spie Batignolles. The consortium also includes Cegelec, GEC Alsthom Electromechanique, Spie Enertrans, all of France, and the local Dogus.

The Yusufeli dam will have a height of 270 metres from its foundation, a crest length of 410 metres, and will impound a reservoir of 20.24 million cubic metres of water. The Artvin dam will have a height of 180 metres from its foundation, a crest length of 278 metres, and will impound a reservoir of 950,000 cubic metres of water. The dams will take about eight years to build.

the 300-MW Borcka dam and the 115-MW Muratli dam, being negotiated by a consortium led by Austria's Elin Union. The consortium also includes Voest Alpine Industrieanlagenbau, JM Voith and Verbund Plan, all of Austria, and the local Yuksel and Temelsu Uluslararasi Muhendislik.

Built from an embankment of rockfill and alluvium, the 86-metre-high Borcka dam will have a crest length of 728 metres, and will impound a volume of 6.25 million cubic metres. Also an embankment of concrete and asphalt coated rockfill and alluvium, the Muratli dam will have a height of 44 metres, a crest length of 483 metres, and will impound a reservoir of 2 million cubic metres. The dams will take about six years to build.