The ponds of the Lower Harz Pond and Ditch System in Germany consist of around 20 small and larger reservoirs. Most were laid out roughly from the beginning of the 17th century between the Upper Lude, Großer Auerberg, Straßberg, Neudorf and Silberhütte. Several of the pond barrages are classified as dams. The dam of the Gräfiggründer Teich is also the second oldest reservoir in Germany.