The Dyke Ditch is the longest artificial ditch in the Upper Harz in central Germany. Its purpose was to collect surface runoff for the operation of the Upper Harz mining industry from precipitation-heavy regions a long way away (particularly from the Bruchberg and parts of the Brocken massif). It was laid in 1732 and continually extended eastwards until 1827. Its original length was about 25 km; this was successively shortened by water tunnels between 1820 and 1861 to around 19 km.
It is a central component of the Upper Harz Water Regale. Its takes its name from the Sperberhai Dyke which is, in fact, an embankment on top of which the Dyke Ditch runs in an aqueduct in order to cross a depression. During its middle years the Dyke Ditch could carry up to 13 million cubic metres of water per year over the Sperberhai Dyke to the Clausthal Plateau. That made it one of the most important lifelines in the Upper Harz mining region.