The Anatolian peninsula is the westernmost point of Asia, divided from Europe by the Bosphorus and anakkale straits. Examination of Turkey's topographic structure on a physical map of the world shows clearly the country's high elevation in comparison to its neighbours, half of the land area being higher than 1000 meters and two thirds higher than 800 meters. Mountain ranges extend in an east-west direction parallel to the north and south coasts, and these are a principal factor in determining ecological conditions. This also means that apart from the Asi river in Anatolia and the Meri in Thracian Turkey all Turkey's rivers have their sources within its borders and flow into the sea, into neighboring countries or into interior drainages.
Turkey has seven river basins.
The principal rivers in the Black Sea basin being the Sakarya, Kizilirmak Yesilirmak and oruh. There are also several rivers with short courses but high water flows in the Eastern Black Sea region, such as the Ikizdere, Hursit ayi and Firtina. The highest waterfall in Turkey is on the Totum river here. The K k Menderes, B y k Menderes and Gediz rivers in the Aegean basin lend their names to the plains which they water. In the Mediterranean basin the principal rivers are the Aksu, K pr ay, Manavgat, G ksu, Ceyhan and Seyhan.