Dyke Ditch

The Dyke Ditch (German: Dammgraben) 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.

The history of the Dyke Ditch was initially closely related to the history of the Sperberhai Dyke. Not until the completion of the dyke in 1734 could large watercourses east of Clausthal be tapped into: the streams of the Großer and Kleiner Gerlachsbach. In the years that followed, the Dyke Ditch was continually extended eastwards. In 1736 it was extended as far as the Kleiner Oker. In 1742, a neighbouring ditch, the Morgenbrodtstal Ditch, was built to carry water from the Große and Kleine Söse rivers to the Dyke Ditch. In 1774, it was lengthened as far as the so-called Wiege ("scales") on the Dyke Ditch and in 1820, after the two Kellwasser tunnels had been driven and the Blochschleife Ditch laid, the Kellwasser and the Blochschleife were connected to the Dyke Ditch system. The last addition was made in 1827, when the Clausthal Flood Ditch, the Flörichshai Ditch and Abbe Ditch enabled water from east of the Bruchberg and the western Brocken to be made available for the Upper Harz mines. Yet another extension would have been possible but was no longer discussed. Now, attempts were made to fundamentally solve the energy problem in the Upper Harz mines by building deeper drainage adits (such as the Ernst August Adit). In addition from the second half of the 19th century other forms of energy (steam engines) were brought into operation, initially alongside water power.

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