Most of the rivers of Turkey flow into the seas surrounding the country. The Fyrat (Euphrates) and Dicle (Tigris) join together in Iraq and flow into the Persian Gulf. Turkey's largest rivers, the Kyzylyrmak, Yeşilırmak and Sakarya, flow into the Black Sea. The Susurluk, Biga and Gönen pour into the Sea of Marmara, the Gediz, Küçük Menderes, Büyük Menderes, and Meriç into the Aegean and the Seyhan, Ceyhan and Göksu into the Mediterranean.
Rivers and Lakes : Turkey has many rivers and lakes. A large number of these rivers are used to generate energy. The rivers generally pour into the seas which surround Turkey, and some reach other seas after leaving Turkeys borders. There are long rivers like the Euphrates, Tigris, Kura, Aras and Çoruh, which originate in Turkey, but pour into the seas in neighboring countries. Kızılırmak, which is 1.355 km., is the longest river stretching completely within Turkeys borders. The Sakarya, which is 824 km., is the second longest. The Tigris, which is 1.263 km. and the Euphrates, 523 km., are the longest rivers that originate in Anatolia. These two rivers, which largely flow to other countries, pour into the Persian Gulf. The Yeşilırmak, Kızılırmak and Sakarya rivers in Central Anatolia flow into the Black Sea; the Susurluk, Biga and Gönen streams in the west flow into the Marmara Sea; and the Gediz, Büyük Menderes and Küçük Menderes flow into the Aegean Sea. The main waterways that flow into the Mediterranean are the Seyhan, Ceyhan and Göksu rivers and the Dalaman and Eşen streams. Eleven percent of Turkeys total area consists of lakes and swamps. Lake Van, located in Eastern Anatolia is the largest of the natural lakes in the country. It has an area of 3,713 km2 and is 451 m. deep. There are many lakes in the Lakes District located in the Western Taurus Mountains The biggest are the Beyşehir and Eğirdir lakes and the Burdur and Acıgöl lakes with brackish water. The lakes around the Marmara Sea are the Sapanca, İznik, Ulubat, Manyas, Terkos, Küçük Çekmece and Büyük Çekmece lakes. Central Anatolia's lakes are shallow and very salty. The Salt Lake which is 1,500 km2 is the second largest lake in Turkey and is located in this region along with the Akşehir and Eber Lakes.