Idyll between Hagen, Herdecke and Wetter

Lake Harkort begins below the Stiftsmühle weir. The weir has four openings closed with rollers and is located under the Ruhr bridge on the B 226 in the urban area of Wetter. The power station and the lock are located approx. 800 metres further downstream and are fed by a diversion ditch (upper ditch). A near-natural fish ladder was put into operation in the area of the power station in 2004, which enables fish to ascend from the Ruhr into the Harkortsee.

Lake Harkort is used for the fine purification of the water flowing in from the Volme and the outflow from the Hagen sewage treatment plant, which is mixed with the water from the Ruhr and Lenne that has already been purified in Lake Hengstey. It also acts as an equalising reservoir for the pumped storage operation at Lake Hengstey. As much water is always released from Lake Harkort as flows into the overall system of Ruhr, Lenne and Volme.

During pumping operation, no water is released from Lake Hengstey into Lake Harkort. The water level of Lake Harkort then drops by up to 50 cm. As soon as the turbines of the Hengsteysee storage power station go into operation, Lake Hengsteysee and Lake Harkort fill up again.

After almost 70 years of operation, large parts of the lake had silted up and some of the water was less than 50 cm deep. For this reason, extensive sediment clearance was carried out between 1999 and 2003, during which around 450,000 cubic metres of sediment were removed. Parallel to the dredging, extensive ecological improvements were carried out in the surrounding area. Examples include the creation of a pike spawning water, the creation of a chain of islands as a refuge for water birds and the creation of still waters.