Agger Dam

Agger Dam is a dam in the Agger valley near Gummersbach that holds back the river water and creates a large lake for water supply and recreation. The wall crosses the valley and forms a sharp line between forested slopes.

Planning began around 1900, but construction only took place between 1927 and 1929 to meet rising energy demands and provide flood protection. This gap shows the long preparations and political negotiations before such large projects.

The name comes from the Agger River, whose waters now gather behind the wall to form a calm body of water. Sailors and rowers use the lake regularly, while divers descend at designated spots to explore the submerged landscape.

Hiking trails run around the water and offer access to different viewpoints along the shores. On warm days it is worth visiting early in the morning or evening to avoid crowds and enjoy the quiet by the water.

In 1967 the entire reservoir had to be drained so that workers could repair cracks in the concrete foundation. The measures included new sealing layers of bitumen and additional concrete to secure the structure for the long term.

Elevation above the sea: 284 m

GPS coordinates: 51.03639,7.63333

Latest update: December 5, 2025 22:29