The Grane Dam (german: Granetalsperre) is a

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use ...

above the village of Astfeld/Herzog-Juliushütte in the borough of

Langelsheim Langelsheim is a town in the district of Goslar in Lower Saxony, Germany. Geography The municipality is situated between the river Innerste and its tributary Grane, on the northern edge of the Harz mountain range and the Harz National Park, loc ...

in the Lower Saxon part of the

Harz The Harz () is a highland area in northern Germany. It has the highest elevations for that region, and its rugged terrain extends across parts of Lower Saxony, Saxony-Anhalt, and Thuringia. The name ''Harz'' derives from the Middle High German ...

mountains.

Dam system

It is the newest dam in the Harz, built in 1969 in the Grane valley. Because the river Grane itself does not deliver enough water for the 3 km long

reservoir A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including contro ...

, a 7.4 km long diversion channel was built from the

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, in length and runs in a generally northerly direction. Origin and meaning of the name The ...

river below the

Oker Dam The Oker Dam (german: Okertalsperre) is a dam in the Harz mountains in Lower Saxony, Germany. It is fed by the River Oker. Technology The dam is in the shape of an arch (see arch-gravity dam). It is 75 m high, 260 m long, can impo ...

. This also collects water from the

Gose Gose () is a warm fermented beer that originated in Goslar, Germany. It is usually brewed with at least 50% of the grain bill being malted wheat. Dominant flavours in gose include a lemon sourness, a herbal characteristic, and a strong salti ...

on the way. A further 4.8 km long diversion runs from the

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 ...

to the Großer Romke and thus into the Oker-Grane Tunnel as well. Likewise there is a 4.6 km long tunnel to the

Innerste Dam The Innerste Dam (german: Innerstetalsperre) is a dam on the Innerste river, which lies near Langelsheim and Wolfshagen in the Harz mountains. It was built between 1963 and 1966 and belongs to the ''Harzwasserwerke''. Its purposes are the su ...

. The operator of the Grane Dam, as well as its associated diversion systems and waterworks is 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. Founded in 1928, the Harzwasserwerke were tasked with sup ...

''. The barrage is an

earth dam An embankment dam is a large artificial dam. It is typically created by the placement and compaction of a complex semi-plastic mound of various compositions of soil or rock. It has a semi-pervious waterproof natural covering for its surface an ...

with asphaltic concrete lining.

Reservoir

The Grane

Reservoir A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including contro ...

(''Granestausee'') supplies

drinking water Drinking water is water that is used in drink or food preparation; potable water is water that is safe to be used as drinking water. The amount of drinking water required to maintain good health varies, and depends on physical activity level, a ...

, acts as

flood protection Flood control methods are used to reduce or prevent the detrimental effects of flood waters."Flood Control", MSN Encarta, 2008 (see below: Further reading). Flood relief methods are used to reduce the effects of flood waters or high water level ...

, water regulation and

electricity generation Electricity generation is the process of generating electric power from sources of primary energy. For electric utility, utilities in the electric power industry, it is the stage prior to its Electricity delivery, delivery (Electric power transmi ...

. The

hydro-electric power station Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined an ...

has a power output of 180 kW. The waterworks for drinking water lies higher up on the northern slope. The water from the reservoir is pumped up into a compensating storage basin of 60,000 m³ capacity, from where it flows to the waterworks. The Grane Dam has an average annual discharge of 55 million m³. Because the reservoir provides drinking water,

water sports Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a s ...

are not allowed. Even motor traffic is kept away from it. A track for maintenance was laid around the reservoir, which is also open to walkers and cyclists and is about 17 km long. There is a checkpoint (no. 110) in the

Harzer Wandernadel The Harzer Wandernadel is a system of hiking awards in the Harz mountains in central Germany. The hiker (or mountain biker) can earn awards at different levels of challenge by walking to the various checkpoints in the network and stamping his or ...

hiking network by the reservoir known as ''Granestausee''.

Notes

* {{citation, surname1=Peter Franke, surname2=Wolfgang Frey, title=Talsperren in der Bundesrepublik Deutschland , publisher=Systemdruck, publication-place=Berlin, isbn=3-926520-00-0, date= 1987, language=German

External links

Harzwasserwerke.de
with link to current dam data Dams in Lower Saxony Dams in the Harz Dams completed in 1969

Dam system

Reservoir

See also

Notes

External links