Image Copyright: Stefan Neuser

The Obernau Dam is the structural barrier of the 86 ha large Obernau reservoir in the southwest of the Rothaar Mountains in the district of Siegen-Wittgenstein, North-Rhine Westphalia (Germany).
The dam of the Obernau reservoir was built after plans by W. Ihssen and G. Salveter from 1967 to 1972. The lake serves as drinking water supply for villages nearby and as flood protection.
The Obernau Dam is situated in the Siegerland, around 9 km (linear distance) northeast of Siegen along the southwest talus of the Rothaar Mountains. It stretches close in the east of Brauersdorf, a northeastern district of Netphen. The lake is towered by the mountains Alte Burg (632,9 m above sea level), location of a former refuge castle and cult site from the La-Tène-time around 500 BC and the Sanktkopf (605,6 m).

Image Copyright: Stefan Neuser

To realise the Obernau Dam in the first place, the villages Obernau and Nauholz in total and parts of the Brauersdorf with altogether 365 citizens had to be relocated. To leave your home, is not an easy task. But, this way the basis for drinking water security in the region was laid.

Image Copyright: Stefan Neuser

About the history of the Obernau Dam

Already in 1931, a report was compiled, which recommended the construction of dams for the protection of drinking water in the region Siegerland-Wittgenstein.

But it took more than 20 years, until the water association was founded on the 9th of September 1953. In the same year, the first groundbreaking took place to construct the Breitenbach Dam and in1956, the first drinking water could be taken from the reservoir.

The year 1959 was an extremely dry year. It brings the truth to light, one reservoir is not enough to cater for the increasing demand of drinking water.

In 1961, the towns Siegen and Eiserfeld become members of the association. Thus, the construction of a second reservoir, the Obernau Dam is definitely needed.

1967 is the year of the first groundbreaking for the construction of the Obernau Dam.

1972, from November onwards, the Obernau Dam is being filled, in May 1973, water is being taken from the waterworks Dreis-Tiefenbach for drinking water treatment for the first time.

1979, the 'Perspective Plan Water Supply' is being submitted, the demand until the year 2020 examined and the trend proved. With that, it becomes clear, that after the Breitenbach Dam, the Obernau Dam also needs a higher capacity. Thus, in 1984, the diversion tunnel is being put into operation, which guides near Walpersdorf additional water from the Upper Sieg river into the Obernau Dam.

In the year 2002, 9 million m3 water was taken from the Obernau Dam reservoir for drinking water treatment.
200.000 people as well as businesses are being supplied with fresh, healthy drinking water every day at any time.