Blue Lake (Dorsten)
|Geographical location||North Rhine-Westphalia , Germany|
|Places on the shore||Dorsten|
The Blue Lake is an artificially created lake in the Dorsten district of Holsterhausen . It has an area of around 15 hectares, is up to eight meters deep, holds 280,000 cubic meters of water and is used as a process water storage facility by RWW Rheinisch-Westfälische Wasserwerkgesellschaft mbH.
The Westphalian sand and clay works Dr. Müller & Co., now Euroquarz GmbH, has been operating a sand mine in the area west of the confluence of the Hammbach and Wienbach streams since the beginning of the 20th century . The sand was extracted by wet mining using a floating shovel excavator, as the pit was filled with groundwater.
After the dismantling was stopped, the blue lake with its white sandy beach and clear "blue" water now also attracted bathers despite the official bathing ban. After the Second World War , crowds also came from neighboring towns in the summer to swim in the Blue Lake. The community-owned, chargeable lido in the immediate vicinity, which had existed since the 1920s, was finally closed due to a lack of visitors.
In 1955, RWW acquired the former sand mine. The sand pit, which was filled with groundwater, was to serve as a reservoir for process water from then on , thereby relieving the pressure on the drinking water works in Dorsten-Holsterhausen. The largest buyers are industrial companies and power plants in the area. The Scholven power plant, for example, draws its cooling water primarily from the Blue Lake. Until it was closed, the Fürst Leopold colliery , which used the water for steam engines , to bind coal dust underground and as cooling water, was another major customer. RWW had the shores of the lake planted and laid out a circular path around the lake. In 1976 the so-called lake water works was expanded.
The lake is fed with water through three entrances: The largest part is taken from the Hammbach by means of a free slope and discharged on the north side. If there is an increased demand, Hammbach water is also supplied to the lake on the south side by means of pumps. In addition, a pumping station operated by the Lippeverband discharges 40,000 cubic meters of groundwater into the lake from the Marienviertel residential area affected by subsidence .
On the east bank are the two extraction devices that feed up to 50,000 cubic meters of water into the pumping station directly on the lake. Currently, around 11 million cubic meters are removed each year. The control and monitoring of inflows and outflows takes place from the central control room of the RWW in the Mülheim-Styrum waterworks.
In the Dorsten-Holsterhausen waterworks , however, drinking water is obtained from well galleries along the Lippe and in the Üfter Mark.
On the Blue Lake is found mainly waterfowl such as mallards , coots and grebes . In autumn, up to 200 cormorants can also be found . The occurrence of bio-indicators such as crayfish , river fleas , caddis-fly larvae and some types of mussels indicate high water quality.
- Rheinisch-Westfälische Wasserwerkgesellschaft mbH (Ed.): 75 years of water supply. 1912-1987. [Mülheim an der Ruhr] 1987
- Walter Biermann: Bathing pleasure. In: Ecumenical history circle Holsterhausen an der Lippe (Hrsg.): Holsterhausen stories. [Dorsten] 1999 p. 105f