Southeastern Anatolia Project (GAP) region in Turkey is rich in water for irrigation and hydroelectric power. The Euphrates and Tigris rivers represent over 28% of the nation's water supply by rivers, and the economically irrigable areas in the region make up 20% of those for the entry country. On the other hand, 85% of the total hydro capacity in operation has been developed by DSI, corresponding to 9931 MW (49 hydro plants) and 35,795 GWhiyear respectively. The largest and most comprehensive regional development project ever implemented by DSI in Turkey is "The Southeast Anatolian (GAP) Project", which is located in the region of Southeast Anatolia on the Euprates and Tigris rivers and their tributaries, which originate in Turkey. The energy potential of the Tigris and Euphrates is estimated as 12,000 GWh and 35,000 GWh, respectively. These two rivers constitute 10% and 30% of the total hydroelectric energy potential. The GAP region will be an important electric power producer with 1000 MW installed capacity from the Karakaya dam, 2400 MW installed capacity from the Ataturk dam and 1360 MW installed capacity from the Keban dam. The GAP region has a 22% share of the country's total hydroelectric potential, with plans for 22 dams and 19 hydroelectric power plants. Once completed, 27 billion kWh of electricity will be generated annually. (C) 2011 Elsevier Ltd. All rights reserved.