Polsterberg Pumphouse
The Polsterberg Pumphouse () is a pumping station above the Dyke Ditch in the Upper Harz in central Germany which is used today as a forest restaurant. As part of the Upper Harz Water Regale it was built in the 18th century and was used to lift the water needed in Clausthal for the mining industry from the Dyke Ditch (Dammgraben) to the level of the highest pond, the Hirschler Pond. Aside from this water hoist, the Dyke Ditch supplied, and still supplies, water over ditches and tunnels to the Hausherzberg Ponds and the Lower Peacock Pond (Unterer Pfauenteich). The problem was however, that, as it happened, the most productive silver mines in the Upper Harz mining region, the Caroline Pit and the Dorothea Pit, were high up in the mountains and could only be supplied with water power from the Hirschler Pond. The motive force for the wooden piston pumps was won in the Polster valley below by two water wheels. The headrace for these water wheels was brought via the Heller Valley Ditch (Hellertal Graben) from the Heller valley and from the Fortune Pond over its Bottom Ditch (Grundgraben), but frictional losses and poor efficiencies meant that a