Shortly after it enters the plain, roughly halfway through its course, the creek Seegraben flows into it from the east.

Like Schwarzbach, Seegraben also originates along Switzerland's northern border in the southern hills of Klettgau, near the Swiss village of Osterfingen and the valley Wangental.

[2] The main route along the plain of Klettgau is Bundesstraße 34, which accompanies the Kotbach and Schwarzbach in their lower reaches.

From Geißlingen, Landesstraße 163 follows the course of the Schwarzbach and passes through its valley, to finally connect to Bundesstraße 27 in Jetstetten.

The ruins of Burg Neu-Krenkingen, one of the castles of the nobile family of Krenkingen, lie above the stream.