Köhm is a small river of North Rhine-Westphalia, Germany. It is 4.4. km long and flows into the Niers near Erkelenz-Keyenberg. Its upper course no longer exists due to lignite mining. The original source of the Köhm was in the area between Garzweiler and Kaiskorb. Here, at an altitude of 120 m above sea level, was the watershed between the Erft and the Rur/Nie…Köhm is a small river of North Rhine-Westphalia, Germany. It is 4.4. km long and flows into the Niers near Erkelenz-Keyenberg. Its upper course no longer exists due to lignite mining. The original source of the Köhm was in the area between Garzweiler and Kaiskorb. Here, at an altitude of 120 m above sea level, was the watershed between the Erft and the Rur/Niers. From here, the Köhm flowed north past Alt-Otzenrath. The area between Garzweiler and Otzenrath is now in the excavated area of the open-cast mine.