raids on Hanover. Water supply The water level loses a maximum of per day through evaporation and water seepage, which equates to of water. In order to maintain a constant level, a pump station at a series of ponds in Ricklingen provides the Masch Lake with a water supply. Its three pumps send water along an pipe to the "source" of the Masch Lake. Depending on weather conditions, between of water are required per year. From November until February no pumping is carried out, so the water level sinks on average during this time. Until 1960, the water level of the Masch Lake was supplied by the Masch Lake Source pump station. Its pumping and filtering houses were one of the first building projects at the site of the lake to be put into operation in November 1935. The plant is equipped with two pumps which are capable of raising of water every second from the Leine. As the Leine is strongly contaminated with suspended sediment, the usage of this water supply meant that the Masch Lake quickly began to silt up. In 1960, the Hanover city administration therefore decided to build a new pump station at the Ricklingen Ponds, in order to supply the lake with groundwater. The old pumping house is only used today when the oxygen content of the water is too low, as this water is supplied to the lake through an open-air three-stage cascading system that raises oxygen levels. It is also put into use during the Today the old pumping house is used as a club house by the Hanover Sport Club. Leisure activities Masch Lake Festival In summer the Masch Lake Festival () is held over several weeks beside the lake, which draws around two million visitors annually. The event was first staged in 1986 to commemorate the 50th anniversary of the lake's opening. It features musical performances, cabaret, cuisine and firework displays. Boats and ships During the summer months the Hanoverian transport company üstra operates boat trips on the lake using electrically powered vessels. Surrounding the Masch Lake are numerous clubs for water sports (most popularly, rowing and sailing). During the year many diverse competitions are held on the lake, including the annual European Dragon Boat Race. Between 1952 and 1989 motor boat competitions were regularly staged on the lake, which saw four world championships contested and ten European champions crowned. Bathing