Kerspe Dam

Unfortunately, the dam cannot be accessed by bike. But below the wall begins a beautiful path towards Rönsahl / Marienheide.

The Kerspe dam serves to produce drinking water for the cities of Wuppertal, Wipperfürth and Remscheid. The gravity dam built from processed quarry stone between 1908 and 1912 dams the Kerspe. The barrier structure was designed by Otto Intze, Aachen. Until December 31, 2015, the dam operator of the facility, which was commissioned in 1913, was the Wuppertaler Stadtwerke (WSW). On January 1, 2016, the dam became the property of the Wupper Association. Storage volume 20 million cbm, annual removal around 27 million cbm. The dam was renovated and reinforced in the 1990s. You got a control passage and a front cut-off wall. (Wikipedia)
The dam is part of a comprehensive water supply system with a number of dams, pipelines and treatment plants to supply the Bergische cities including an emergency line to Düsseldorf.
Because of water protection zone 1, the dam is completely fenced.

even if everything is fenced it is worth it