The Hasper dam or Haspertalsperre is a dam that was built from 1901 to 1904 to plans by Otto Intze by the city of Haspe (now district of Hagen) in the Ruhr area (North Rhine-Westphalia) for drinking water. It is one of 14 dams in the river system of the Ruhr. The inauguration took place on October 11, 1904.
The dam wall of the Haspertalsperre is a curved gravity dam made of quarry stone masonry according to the Intze principle. The jammed water is the Hasper brook. The Haspertalsperre has a pre-basin, the Schöpplenberger pond.
In the years 1991 to 1994, the dam was renovated and reinforced with a superior sealing shell. She was also increased by 40 cm. It belongs to the Mark-E Aktiengesellschaft.
The two turrets of the dam were originally located in the middle, but have now been moved outward to the wall end. In the original locations, two steering wheels are reminiscent of the towers. There is also a circa five kilometer round trail around the dam.
Originally located near the dam was the breakpoint Hasper dam of the Kleinbahn Haspe-Voerde-Breckerfeld, later tram line 11, which was often the starting point for walks around the dam. Today, the so-called Plessen Viaduct recalls the narrow gauge railway, which was used to cross the valley. The later bus traffic to the dam was set on May 22, 1977, so that the lock is now only accessible on foot or by car.