The Ennepetalsperre has a height of around 51 metres with a crown length of 320 metres and a crown width of 4.5 metres.
The quarry stone wall of the Ennepetalsperre, built according to designs by Prof. Otto Intze, was raised by around ten metres between 1909 and 1912 - shortly after it was built.
The main tributary of the dam is the Ennepe. This flows into the Volme in Hagen and four kilometres further on into the Ruhr. The Ennepetalsperre includes the Osenberg forebay and six side basins. The forebay and two side basins near Altenfeld and Altena were dredged between 2008 and 2009 as they had shrunk to less than 60 per cent of their original size over the years due to sediment deposits.
The dam wall was repaired in 1997. A tunnel boring machine was used to excavate an inspection gallery through the foundation of the dam wall. The lower half of its cross-section lies in the natural rock on which the wall stands and the other half lies in the wall. This required a great deal of technical effort, as the inspection gallery had to follow both the curvature of the wall and the profile of the valley in order to always run along the interface between the wall and the ground. The purpose of the inspection gallery is to drain seepage water that has entered between the wall and the rock and into the wall itself. This is intended to reduce the water pressure at the base of the barrier wall.
After the repairs, the crown was closed to road traffic.
The Ennepetalsperre is used for drinking water production. AVU Gevelsberg, the legal successor to the former water supply company of the Schwelm district, currently extracts nine million cubic metres of raw water per year from the dam.
A hydropower plant has also been installed at the Ennepetalsperre since the beginning of 2006. The existing flow-through turbine has a maximum capacity of 1.4 cubic metres per second. The average annual production is 1.5 million kilowatt hours, which is fed into the power grid. The hydropower plant is operated by Lister-Lenne-Kraftwerke GmbH in Olpe, a wholly owned subsidiary of the Ruhrverband.
The drinking water reservoir offers a unique refuge for flora and fauna. In order to avoid any pollution of the water through agricultural or recreational use, a water protection area ordinance applies in the catchment area with strict conditions for the use of the dam and its catchment area. This is a restriction for those seeking recreation, but offers plants and animals a valuable and undisturbed habitat.
Tasks and function
During our tours, you will learn interesting facts about the construction, water supply and operation of our dams.
The average annual production of the hydropower plant at the Ennepetalsperre dam is 1.5 million kilowatt hours, which is fed into the electricity grid.
As a drinking water reservoir, the Ennepetalsperre is not authorised for water sports.
Sport & Leisure
With a water surface area of 103 hectares, Lake Ennepe is located in the south-west of the town of Breckerfeld in the Ennepe-Ruhr district. Lake Ennepe is one of the Ruhrverband's drinking water reservoirs. It stretches over a length of 4 km and is up to 200 metres wide. At full water level, the maximum water depth is 35 metres.
You can find more detailed information about fishing at the Ennepetalsperre on our fishing website.
As a drinking water reservoir, the Ennepetalsperre is not authorised for water sports.
As a drinking water reservoir, the Ennepetalsperre is not authorised for passenger shipping.
As a drinking water reservoir, the Ennepetalsperre is not authorised for water sports.
As a drinking water reservoir, the Ennepetalsperre is not authorised for water sports.
As a drinking water reservoir, the Ennepetalsperre is not authorised for water sports.
History
History
When the Ennepetalsperre was planned at the end of the 19th century, the crude steel and steel processing industry in Ennepetal was in full bloom. In 1899, Prof Otto Intze from the Technical University of Aachen was commissioned with the planning. The clients were the owners of the Ennepe power station who, once the financing of the construction was secured, joined forces with other donors in 1901 to form the Ennepetalsperren-Genossenschaft (later the Ennepe Water Association).
The ground-breaking ceremony for the construction of the dam took place on 29 January 1902. An eight-kilometre railway line was built from Radevormwald station to the dam wall. Initially used exclusively for transporting materials, the regional council quickly granted permission for passenger transport at the request of the construction management, as the construction site was very popular with tourists. The railway line was dismantled at the end of the construction period.
Shortly after construction was completed, the dam wall was raised in 1912 as the original reservoir volume was insufficient. This made it possible to achieve an even annual discharge. The reservoir volume was increased from 10.3 million cubic metres to the current 12.6 million cubic metres.
On the night of 16th to 17th May 1943, British bombers carried out a major attack on German dams with special rolling bombs as part of Operation Chastise. The Ennepetalsperre was also one of the targets that night. However, because it was so hidden and difficult to locate, it remained undamaged, while its much larger "sisters" on the Eder and Möhne were hit with devastating consequences.
In 1997, the Ennepetalsperre was taken over by the Ruhrverband in Essen. Between 1997 and 2002, almost all areas of the dam were rehabilitated. Due to the importance of the dam for the local drinking water supply, the state of North Rhine-Westphalia subsidised the project. To guarantee the water supply, the dam remained full throughout the entire renovation work.
The dam wall of the Ennepetalsperre has an "unfavourable geometry" for earthquakes due to the subsequent increase in height by ten metres to a total of 51 metres and is therefore potentially sensitive to extremely rare, strong earthquakes. The Ruhrverband therefore operates two earthquake stations at the Sorpe dam (since December 1998) and at the Ennepetal dam (since October 2000).
A hydropower plant has been in operation at the Ennepetalsperre dam since the beginning of 2006. The through-flow turbine has a maximum capacity of 1.4 cubic metres per second. The average annual production is 1.4 million kilowatt hours, which is fed into the electricity grid. The hydropower plant is operated by Lister-Lenne-Kraftwerke GmbH in Olpe - a wholly owned subsidiary of the Ruhrverband.
From 2013 to 2015, around ten years after the completion of the extensive renovation, the so-called "in-depth inspection" of the Ennepetal dam took place. The need for an in-depth inspection arises from the state water law and can be compared to the regular MOT inspection of a car.
