Çoruh

The Çoruh is a river that rises in the Mescit Mountains in north-eastern Turkey, flows through the cities of Bayburt, İspir, Yusufeli, and Artvin, along the Kelkit-Çoruh Fault, before flowing into Georgia, where it reaches the Black Sea just south of Batumi and a few kilometers north of the Turkish-Georgian border.

In Arrian's Periplus Ponti Euxini, it is called the Acampsis ; Pliny may have confused it with the Bathys. Procopius writes that it was called Acampsis because it was impossible to force a way through it after it has entered the sea, since it discharges its stream with such force and swiftness, causing a great disturbance of the water before it, that it goes out for a very great distance into the sea and makes it impossible to coast along at that point.

Wikipedia