Throughout history, water has always been a very important element for man in the development of his environment, for agricultural and industrial production, and for transportation. Therefore people prefer to live close to or in areas served by rivers.
520 billion cubic m / 680 billion cubic yards of water (rain, snow, etc.) fall annually in Turkey and 32% of this amount forms rivers. Although this is a very large volume of water, not many of the rivers are very long. They are plentiful in number due to the existence of many hills, ranges of mountains, plateaus and plains in the country.
Generally, rivers originate from heights of 1,000-2,000 m / 3,280-6,560 ft and flow into the sea after 700-800 km / 435-500 miles which is a comparatively short distance. Consequently their speed is fast and they carry large amounts of alluviums. These alluviums have contributed to some of the geological formations over the centuries. The harbors of some ancient cities such as Ephesus, Priene or Troy, which once graced shorelines, are present day ruins located a few kilometers inland due to silting up of shores. The lakes of Bafa and Sapanca were once bays before their entrances became closed by alluvium deposits.
In spring, especially in April, the rivers carry the maximum amount of water which is muddy in color because it carries a lot of soil. The season in which the minimum water is carried is the autumn, especially September.
The majority of the rivers in Anatolia are not navigable, having irregular, shallow beds and seasonal depth changes.
Often many rivers are named according to their colors; Kizilirmak (red river), Aksu (white water), Bozcay (gray river), sometimes with the names of places or surrounding things; Degirmendere (mill river), Koprucay (bridge river), or with some adjectives describing the nature of the river; Delicay (crazy river), Cehennemdere (hell river), Ikizdere(twin rivers).
Most Turkish rivers originate within the country's borders, a feature which gives Turkey a strategic power because there is no risk of water limitation by its neighbors.

Rivers of Anatolia
The Euphrates and Tigris join together in Iraq and flow into the Persian Gulf. Less than half of the Euphrates and one third of the Tigris are within Anatolia today.
The Kizilirmak (Halys) is the longest river originating and flowing within the borders of Turkey; 1,355 km / 842 miles.
Yesilirmak and Sakarya are the longest rivers after the Kizilirmak, and flow into the Black Sea.
The Aras and Kurucay flow beyond Turkey’s borders into the Caspian Sea in western Asia.
The Susurluk, Biga and Gonen flow into the Marmara Sea.
The Gediz, Buyuk Menderes, Kucuk Menderes and Meric flow into the Aegean Sea.
The Seyhan, Ceyhan and Goksu flow into the Mediterranean Sea