The Dyke Ditch () is the longest artificial

ditch A ditch is a small to moderate trench created to channel water. A ditch can be used for drainage, to drain water from low-lying areas, alongside roadways or fields, or to channel water from a more distant source for plant irrigation. Ditches ...

in the

Upper Harz The Upper Harz (, ) is the northwestern and higher part of the Harz mountain range in Germany. The exact boundaries of this geographical region may be defined differently depending on the context. In its traditional sense, the term Upper Harz cover ...

in central Germany. Its purpose was to collect

surface runoff Surface runoff (also known as overland flow or terrestrial runoff) is the unconfined flow of water over the ground surface, in contrast to ''channel runoff'' (or ''stream flow''). It occurs when excess rainwater, stormwater, meltwater, or other ...

for the operation of the Upper Harz mining industry from precipitation-heavy regions a long way away (particularly from the

Bruchberg At , the Bruchberg in the Upper Harz is the second highest mountain in Lower Saxony and the third highest in the Harz mountains in North Germany. It lies between Altenau and Torfhaus in the middle of the Harz National Park. The Bruchberg is more ...

and parts of the

Brocken The Brocken, also sometimes referred to as the Blocksberg, is a mountain near Schierke in the German state of Saxony-Anhalt, between the rivers Weser River, Weser and Elbe. The highest peak in the Harz mountain range, and in Northern Germany, ...

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 Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...

between 1820 and 1861 to around 19 km. It is a central component of the

Upper Harz Water Regale The Upper Harz Water Regale (, ) is a system of dams, reservoirs, ditches and other structures, much of which was built from the 16th to 19th centuries to divert and store the water that drove the water wheels of the mines in the Upper Harz region ...

. 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.

History

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

and the western

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. In the middle of the 19th century work was carried out to optimise water flow in area of the 10 km long section between Sperberhai Dyke and Clausthal. By cutting tunnels, several ditch detours around mountains were able to be shortened considerably. In addition to clear advantages in the maintenance overhead and winter operations, the increase in incline (the same drop being covered in a shorter distance) played an important role in increasing the hydraulic capacity. The water tunnels, built around 1850, were the Rothenberg, Coventhai, Dietrichsberg and Bielenwiese Tunnels. 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. Following the closure of the mines the Dyke Ditch supplied water up to about 1978 for the generation of electricity in Kaiser Wilhelm Shaft. Since 1978 the water of the Dyke Ditch has been led to the Mönch valley of the Oker Reservoir at the end of the Dyke Ditch, where it still drives turbines for the generation of electricity and is then made available for the drinking water supplies of the

Harzwasserwerke The Harzwasserwerke GmbH (; English: Harz Water Works Limited) is a major German water company and dam operator based in Hildesheim, located within the German federal state of Lower Saxony. History Founded in 1928, the Harzwasserwerke were task ...

. Until about 2000, the Dyke Ditch also provided drinking water to the mining town of

Altenau Altenau () is a town and a former municipality in the district of Goslar, in Lower Saxony, Germany. Since 1 January 2015 it is part of the town Clausthal-Zellerfeld. It is situated in the middle of the Harz mountains, between Clausthal-Zellerf ...

. This has since been withdrawn because the natural water supply was very unreliable, especially in winter and the quality of the water could also change very quickly. The operator of the Dyke Ditch today is the ''

''.

Catchment area

The Dyke Ditch draws its water from the region of six Harz rivers: *

Söse Söse () is a river of Lower Saxony, Germany. It is a right tributary of the river Rhume and long. Geography The Söse rises on the plateau of ''Auf dem Acker'' in the district of Göttingen in the southwestern part of the Harz Mountains in ...

over the Morgenbrodstal Ditch (1715–1718; length 3,970 m) * Sieber over the Clausthal Flood Ditch (also called the Rotenbeeke Ditch) (1797; length 3,900 m) *

Oder The Oder ( ; Czech and ) is a river in Central Europe. It is Poland's second-longest river and third-longest within its borders after the Vistula and its largest tributary the Warta. The Oder rises in the Czech Republic and flows through wes ...

over the Clausthal Flood Ditch and the Flörichshai Ditch (1826; length 1,050 m) *

Ecker The Ecker is a , right-hand, southeast tributary of the Oker which runs mainly through the Harz mountains in the German states of Saxony-Anhalt and Lower Saxony. Course From its source to Abbenrode the Ecker is a border river, today running b ...

over the Abbe Ditch (1827; length 1,540 m) *

Radau Radau is a river of Lower Saxony, Germany. It is right tributary of the Oker. It rises in the Harz range, leaves the mountains at Bad Harzburg, and discharges into the Oker near Vienenburg. Course The river rises at around in the Upper Harz re ...

over the Abbe Ditch *

Oker The Oker () is a river in Lower Saxony, Germany, that has historically formed an important political boundary. It is a left tributary of the River Aller (Germany), Aller, in length and runs in a generally northerly direction. Origin and meanin ...

over the Dam Ditch (1725–1840; length 14,690 m) The Dyke Ditch system crosses several

watershed Watershed may refer to: Hydrology * Drainage divide, the line that separates neighbouring drainage basins * Drainage basin, an area of land where surface water converges (North American usage) Music * Watershed Music Festival, an annual country ...

s as a result.

Statistics

The Dyke Ditch today is 19 km long. 15.4 km of that are open ditches and 3.6 km are underground water tunnels. Depending on how they are counted, its associated ditch system has an overall length of 49 km. On most routes the water descends by around 60 m. Its flow rate reaches a maximum of about 1 m³/s.

Footpath

A footpath from Osterode to

Thale Thale () is a town in the Harz (district), Harz district in Saxony-Anhalt in central Germany. Located at the steep northeastern rim of the Harz mountain range, it is known for the scenic Bode Gorge stretching above the town centre. Geography The ...

, the

Harzer Hexenstieg The Harz Witches' Trail () is a footpath, just under 100 km long, in Germany that runs from Osterode through the Harz mountains and over its highest peak, the Brocken, to Thale. It is a project by the Harz Transport Association and Harz ...

("Harz Witches' Climb"), runs along the Dam Ditch.

Sources

* * {{Coord, 51, 48, 10, N, 10, 30, 12, E, type:waterbody_elevation:640_region:DE-NI, display=title Upper Harz Water Regale Clausthal-Zellerfeld Kunstgraben CDammgraben CDyke Ditch