The historic water tank played an important role in the water supply of the Einbeck grain mills and was built in the Middle Ages. It is known as the place where "one water leads over the other".
early 15th century A municipal mill ditch was built, the so-called Mill Canal, which branched off at the Village of Hullersen from the Ilme, flowed along the Walkemühle as well as at the Upper, Middle and Lower Mill The Upper Mill is located at the Diekturm, the Middle Mill was located opposite the present fire station, and the Lower Mill was at the end of Baustraße, opposite the KAYSER Filtertech Group. Finally, it crossed the city wall and the city moat. It flowed over the Krummen Wasser streambed at the bridge and into the Ilme, continuing into Towards Salzderhelden.
Thefour municipal mills Walkemühle, Obere, Mittlere and Niedere Mühle could powered by this water channel However, this required the mill canal to be diverted over the Krumme Wasser and under the city wall. For this purpose, the wooden water tank, from the 1824 as well as a steel construction The passage under the wall, which can be seen today, was, according to inscriptions 1559 either erected or repaired and expanded in 1573.