It is located near Hasselfelde in the state of Saxony-Anhalt and impounds the waters of the Hassel, the eastern of the two headwaters of the Rappbode Reservoir.

The purpose of the auxiliary dam is to pre-clean water mechanically and biologically before it flows into the main reservoir.

The bedrock consists mostly of grauwacke, but with some thinly laminated argillaceous shale as well.

There is a circular path around the Hassel Auxiliary Dam.

The crest of the dam is accessible to pedestrians and the lake may be fished provided permission is obtained.