I couldn't find any evidence that the Phoenicians used the Tigris and Euphrates Rivers.
Ancient Egyptians used the water from the Nile to grow crops, and they planted these crops in the rich soil left by the annual floods. Of course, the Nile also provided transportation.
How did the Phoenicians use the Tigris and Euphrates River?
How did the Ancient Egyptians use the Nile River?
3 answers
Then what river did the Phoenicians use?
They didn't use rivers much. They sailed all over the Mediterranean Sea.
https://en.wikipedia.org/wiki/Phoenicia#/media/File:PhoenicianTrade.png
https://en.wikipedia.org/wiki/Phoenicia#/media/File:PhoenicianTrade.png