Wikipedia
Simoeis ( Simóeis) was a river of the Trojan plain and the name of its god in Greek mythology. Like other river-gods, Simoeis was the son of Oceanus and Tethys. Simoeis had two daughters who were married into the Trojan royal family. One daughter, Astyoche, was married to Erichthonius, and the other daughter, Hieromneme was the wife of Assaracus. When the gods took sides in the Trojan War, Simoeis supported the Trojans. Scamander, another river who also supported the Trojans, called upon Simoeis for help in his battle against Achilles:
Come to my aid with all speed, fill your streams with water from your springs, stir up all your torrents, stand high in a great wave, and rouse a mighty roar of timbers and rocks, so we can stop this savage man who in his strength is raging like the gods.
( Iliad, 21.311-15).
Before Simoeis could respond, Hephaestus was able to save Achilles by subduing Scamander with flame.