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A Mahlbusen is the extension of a receiving water in front of a pumping station in the form of a (small) lake that collects and temporarily stores water.

  • A receiving waterway is a larger drainage ditch or river which, in accordance with DIN 4045, allows water or sewage to flow away through a natural gradient or artificial uplift.
  • Pumping stations ensure the permanent or temporary outflow from flowing or standing water, which is permanently or temporarily lacking a natural receiving water, usually installed at the lowest point of the polder with upstream grinding bays.
  • Permanent pumping stations convey the entire inflow from an area that has no natural receiving water.
  • Flood pumping stations only support when natural receiving water is insufficient.

A side effect of the Mahlbusen is the retention of mud, sand and other sediments by interrupting the flow.

Finkenrieker Mahlbusen in Hamburg-Wilhelmsburg

Finkenrieker Mahlbusen with the confluence of the southern Wilhelmsburger Wetter

53 ° 28 ′ 32 ″ N, 10 ° 0 ′ 36 ″ E
Although the Elbe island of Wilhelmsburg is around 100 km from the North Sea, it is by definition a polder , i.e. a land protected by dykes or drained by dykes. Polders are usually better known from the North Sea coast.

On this low-lying river island, which is protected by about 8 m high dykes , there is a small lake between the streets König-Georg-Deich, Finkenrieker Deichweg and Finkenrieker Hauptdeich (which is a lake dike), into which all drainage ditches from the south Wilhelmsburg flow. The trenches in Wilhelmsburg, locally called “ Wetter ” in local dialect , have the task of collecting water in the polder and delivering it to sluices or pumping stations. However, without additional measures, they only have a draining effect when the receiving water is free.

The small lake described here is the Finkenrieker Mahlbusen. The (rain) water that has collected in the Mahlbusen is to be disposed of in the Süderelbe . At normal water levels on the Elbe, the water flows off through the natural gradient, as the water level of the Mahlbusen is then higher than that of the Elbe. This is a classic flood pumping station, the work of which is only necessary if the receiving water is insufficient. In the case of high water levels in the Elbe (e.g. during storm surges such as 1962 and 1976 ) pumps must be used in pumping stations to transport the water collected in the Mahlbusen into the Elbe which is then higher up. If this facility did not exist and there was both Elbe flooding and continuous rain, the permissible inland water level in Wilhelmsburg would be exceeded with corresponding consequences, such as areas under water, streets, cellars, etc.

Mahlbusen on the Kuckuckshorn (Hamburg-Wilhelmsburg)

53 ° 29 ′ 32 ″ N, 9 ° 59 ′ 42 ″
E Another Mahlbusen is located in the middle of the diked Hamburg-Wilhelmsburg on the Kuckuckshorn. The associated pumping station drains water through a pressure pipe into the Reiherstieg, around 800 meters further west.

Wremer Mahlbusen

Wremer Mahlbusen (left) with barrage (background) in the receiving water, which drains to the right towards the dike

53 ° 39 ′ 5 ″ N, 8 ° 29 ′ 56 ″
E The Mahlbusen in Wremen has an additional function. It not only improves the drainage of the interior, but also serves to flush the Wremer Prielhafen, which tends to silt up, especially when there is little rainfall. For this purpose, the Wremer Mahlbusen can be specifically filled with seawater at high tide. A barrage in the receiving water behind the Mahlbusen prevents further penetration of salt water into the interior. When the tide is out, the water from the Mahlbusen is available to flush out the Wremer Prielhafen.

More grinding breasts

Another example of a Mahlbusen is the bay at the end of the Knockster Tief near Emden. 53 ° 20 ′ 25 ″ N, 7 ° 2 ′ 1 ″ E In Lower Bavaria there is a grinding bosom at the Alte Kinsach pumping station on the Danube near the town of Bogen .