The dam wall of the Möhnesee was built in the period 1908-1913 with quarry stones and is today an imposing technical monument. The dam and the dam wall still serve the purpose of supplying water to the Ruhrgebiet. The largest wall width is 34.2 m, at the crown the wall is 6.25 m wide. The crown length is 650 m. Thus, the dam can withstand the water pressure of 134.5 million m3 of water (at full dam). During World War II, the dam was destroyed over a length of 77 m in a bombing raid on the night of May 16-17, 1943, and was rebuilt in the same year.
Against the background of environmental and climate protection, other tasks of the Möhnesee are increasingly coming into focus. The two power plants, which were integrated into the dam from the very beginning, continue to supply climate-neutral electricity today. And the Hevearm and Hevesee nature reserves are Westfalen's largest resting area and wintering grounds for waterfowl.