Rapids

What is the name of river next to the Magdalena in Columbia?

There are two large rivers running north-south parrallel in Colombia. One is called the magdalena, what is the other called?????????

Public Comments

1. The Cauca river http://worldatlas.com/webimage/countrys/samerica/lgcolor/cocolor.htm
2. The Cauca river
3. Cauca river