Oderteich
Encyclopedia
The Oderteich is an historic reservoir
about seven kilometres northeast of Sankt Andreasberg
in the Upper Harz
in central Germany
. It was built by miners from St. Andreasberg in the years 1715 to 1722 and, today, is an important component of the water supply network known as the Upper Harz Water Regale
(Oberharzer Wasserregal). Moreover, for 170 years, from the time it was completed to the end of the 19th century, the Oderteich had the largest dam in Germany
. The dam
lies at a height of by the B 242
federal highway, about a kilometre west of its intersection with the B 4
.
s of the St. Andreasberg mine
via the Rehberg Ditch, even during times of drought. Its capacity of 1.7 million cubic metres was, far and away, the largest of all the Upper Harz reservoirs at that time and was enough to cope with periods of low precipitation of up to three months.
Today the water of the Oderteich still drives several hydropower
stations within its own valley, at the Samson Pit
and in the Sperrlutter
valley.
The dam also serves to prevent the regular flooding that happened each year in spring before the dam was built.
and bringing it to St. Andreasberg. This was initially a great improvement in the supply of water power for the mines there, but the Oder could still not deliver enough water during a period of extended drought. So the call for a water reservoir quickly became shrill.
A glance at the Upper Harz 'ponds' (Teiche) near Clausthal-Zellerfeld and Hahnenklee suggested a solution. At that time there must have been 50 to 60 small reservoirs in operation. Their design, however, could not simply be copied, because there was nowhere in the vicinity of the Oderteich to cut grass sods like those used to seal the dams of the Upper Harz reservoirs.
In the meantime, the Rehberg Ditch, which had initially only been made of wooden channels (Holzgefludern), was being 'walled'; in other words the wooden conduits were being replaced by a considerably more durable artificial ditch made of earth embankments and dry stone walls. In doing so it was realised that the sand resulting from the weathering of granite, so-called granitgrus, if it was thoroughly tramped down, produced a very good seal.
In 1712, the deputy chief miner (Vizebergmeister), Caspar Dannenberger, wrote two letters to the Clausthal Mining Office, in which he proposed the construction of the Oderteich dam, sealed with granitic sand, as well as two embankments made of granite blocks. This proposal was duly taken up, but Caspar Dannenberger, the father of the Oderteich dams, did not survive to see it completed. He died on23 April 1713.
Planning was carried out in 1714 and, on 14 September, King George Louis
authorised the construction of the Oderteich dam in a most gracious special decree and made the available the sum estimated for the project: a total of 3048 thaler
s and 27 gl.
The construction phase actually started in early 1715. Initially a core trench was excavated into which the dam was embedded. The building material for this was excavated from the land earmarked for the future reservoir. Granite blocks needed for the up- and downstream sides of the dam were cut from small quarries; this also provided a supply of granitic sand. The mining of material for the dam enabled the future reservoir capacity to be further enlarged.
The work took until 1722. Because excess water could neither be drained through the relatively small bottom outlet during the construction period nor be impounded, a spillway
had to be continuously available whilst the dam was being built. This spillway had to be laid higher and higher as the dam grew in size.
Shortly after work on the dam had started there were discussions about raising it even higher than originally planned. In 1717 it was agreed to increase its height from the initial seven Lachter
to nine Lachter (roughly equating to just under 18 metres). This resulted in an increase in the dam volume of around 55 percent and a doubling of the reservoir capacity to 1.67 million cubic metres.
The cost of construction rose considerably during the build phase, not just as a result of the increase in dam height, but also other factors: in the end the Oderteich dam cost around 11,700 Reichstalers, almost four times the originally estimated and approved cost. Because the structure was so convincing, however, subsequent requests and approvals for the additional extra funding were not a problem. The three chief miners (Bergmeister) and excavation engineers (Grabensteiger) were rewarded in 1724 with bonuses ranging from 12 to 100 Talers.
The Sankt Andreasberg mine ground to a standstill in 1913. From then on the water of the Oderteich was used to generate electricity instead. It was now routed to Sankt Andreasberg itself, where it was used in several power stations and especially the Samson Pit. The water is still used for this purpose today and guarantees the economic operation and maintenance of the Oderteich and Rehberg Ditch.
In the late 1920s the Harzwasserwerke
planned a further significant increase in the height of the Oderteich Dam. The dam and the geology of the surrounding area were thoroughly examined. Digging exposed the seal of granitgrus and it was confirmed that this could not easily be worked with clay picks. These plans were later shelved for reasons that are not clear, although it is likely that the project was not seen as economical.
made of large blocks of granite with a slope of 1:0.5. On the downstream side the dam measures about from its base.
The dam wall has proved to be a very durable structure and, like the entire reservoir, is still virtually in its original condition.
Fundamentally it is not quite clear whether the Oderteich dam structure is an earth-fill dam or a masonry dam
. It is probably a combination of the two.
which ensures that even under conditions of exceptionally high water, the water does not rise to an uncontrollably high level, possibly even pouring over the dam crest. On the Oderteich the spillway is located at the left hand (eastern) end of the dam.
In the reservoir in front of the outlet are several stone columns, like standing stones
in appearance, about 2.50 metres high and made of granite. They serve to keep ice floes away from the spillway, because these could jam the channel. The old outlet is clearly identifiable by a weir, which was built in 1895 by the Royal Central Smithy in Clausthal Königlichen Centralschmiede Clausthal. This weir enables the maximum storage level to be raised by a metre or so.
Originally the spillway ran for almost a 100 metres in a straight line southwards before the water dropped into the valley. This course is still visible in the terrain to the experienced eye. But when towards the end of the construction phase in there were still not enough stones to complete the dam wall, a steep, 80 metre-long Große Ausflut ("large spillway") was blasted out of the rock roughly 60 metres below the weir at right angles to the original spillway. Perhaps it was hoped that this would increase the hydraulic capacity
of the outlet. The channel carved out of the rock is very impressive especially on the spillway.
To begin with the spillway was not large enough: in December 1760 water overspilled the dam during a period of exceptional high water. Damage was limited, which said something, especially about the stable design of the dam. In response to this incident the dam was raised by about a metre, which has probably merely compensated for the subsidence of the dam since that time.
In 1886/87, however it appears that the conclusion was reached that the capacity of the spillway needed to be increased. To achieve this another spillway was built a few metres east of the existing one. It had an inlet breadth of 12 metres and its crest was about a metre higher than that of the old, main spillway. This outlet crosses under the B 242 parallel to the main one and merges with the main spillway shortly before the high water marker and its adjoining chute (Schussrinne). This additional spillway enables the discharge capacity during times of flood to be increased by about 50 %.
The surcharge capacity of the Oderteich is very small. Its reservoir can only store 14 % of its annual discharge. This results in unusually high fluctuations in the water level of the reservoir, which can even change from being largely empty to overflowing within a few hours. This explains why the Oderteich overflows several times a year.
. Humic acid also causes its brown coloration. In addition, it reduces surface tension
, something which causes conspicuous white horses such as occur in the turbulence at the intakes and outlets of the reservoir.
, DIN 19700-11. What is true is that from its completion in 1722 to the end of the 19th century, a period of 170 years, it had the largest dam in Germany. Not until the Eschbach Dam in the Bergisches Land
was finished in 1891 with a height of was there a higher dam than the Oderteich.
, laid out a waterside footpath (the WasserWanderWeg) as an educational trail. This runs along the dam crest to the two spillways, past the two additional basins and via the overspill marker then downhill alongside the Großer Ausflut and its chute to the downstream foot of the dam, from where there is an impressive view of the stonework on this side of the dam and where the bottom outlet and start of the Rehberg Ditch can be seen. Information boards along the path explain the various structures.
. Swimming is allowed in the southern third of the reservoir and in the vicinity of the dam. The northern area is barred to swimmers in the summer by a chain and is meant to be exclusively reserved as a biotope
. There is a roughly 4.5 km long circular walk around the reservoir, for which good walking boots are recommended. This path is routed along board walks in places because of the terrain which resembles that of a raised bog.
Winter sports, such as skating, on the reservoir in winter are not recommended, because the large variations in the water level make the formation of a stable ice surface difficult, especially near the shores.
Reservoir
A reservoir , artificial lake or dam is used to store water.Reservoirs may be created in river valleys by the construction of a dam or may be built by excavation in the ground or by conventional construction techniques such as brickwork or cast concrete.The term reservoir may also be used to...
about seven kilometres northeast of Sankt Andreasberg
Sankt Andreasberg
Sankt Andreasberg is a town and a former municipality in the district of Goslar, in Lower Saxony, Germany. Since 1 November 2011, it is part of the town Braunlage. It is situated in the Harz, approximately 7 km west of Braunlage proper, and 20 km east of Osterode am Harz.- History :Sankt...
in the Upper Harz
Upper Harz
The Upper Harz refers to the western and higher part of the Harz mountain range in central Germany. Much of the Upper Harz is over , but at its eastern edge in the High Harz it climbs to over on the Brocken massif.- Geography :...
in central Germany
Central Germany (geography)
In geography, central Germany describes the areas surrounding the central point of modern-day Germany.The town of Niederdorla, in the state of Thuringia, claims to be the most central town in Germany...
. It was built by miners from St. Andreasberg in the years 1715 to 1722 and, today, is an important component of the water supply network known as the Upper Harz Water Regale
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 of Germany...
(Oberharzer Wasserregal). Moreover, for 170 years, from the time it was completed to the end of the 19th century, the Oderteich had the largest dam in Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
. The dam
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...
lies at a height of by the B 242
Bundesstraße 242
- Route :The B 242, also known as the Harz High Road , runs right across the Harz mountains in central Germany. From Seesen on the northwestern edge of the Harz near the A 7 motorway it runs through the Upper Harz past Clausthal-Zellerfeld, the High Harz, where it is combined for several kilometres...
federal highway, about a kilometre west of its intersection with the B 4
Bundesstraße 4
The Bundesstraße 4 is a German federal highway running in a northwesterly to southly direction from the state of Schleswig-Holstein to Bavaria...
.
Purpose
The Oderteich was built in order to be able to deliver a reliable supply of water to the water wheelWater wheel
A water wheel is a machine for converting the energy of free-flowing or falling water into useful forms of power. A water wheel consists of a large wooden or metal wheel, with a number of blades or buckets arranged on the outside rim forming the driving surface...
s of the St. Andreasberg mine
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
via the Rehberg Ditch, even during times of drought. Its capacity of 1.7 million cubic metres was, far and away, the largest of all the Upper Harz reservoirs at that time and was enough to cope with periods of low precipitation of up to three months.
Today the water of the Oderteich still drives several hydropower
Hydropower
Hydropower, hydraulic power, hydrokinetic power or water power is power that is derived from the force or energy of falling water, which may be harnessed for useful purposes. Since ancient times, hydropower has been used for irrigation and the operation of various mechanical devices, such as...
stations within its own valley, at the Samson Pit
Samson Pit
The Samson Pit or Samson Mine is an historic silver mine in Sankt Andreasberg in the Upper Harz region of central Germany.The pit has one of the oldest man engines in the world still working and it can be seen in operation during guided tours. The man engine, installed in the Samson Pit in 1837,...
and in the Sperrlutter
Sperrlutter
The Sperrlutter is a roughly long tributary of the Oder between Sankt Andreasberg and Bad Lauterberg in the Harz Mountains. It rises at about 700 m in the vicinity of the Glückaufklippen. It flows initially south through the village of Silberhütte and the Sperrlutter valley...
valley.
The dam also serves to prevent the regular flooding that happened each year in spring before the dam was built.
History
In 1703 the new Rehberg Ditch was completed, diverting water from the river OderOder (Harz)
The Oder is a 56 km long river in Lower Saxony, Germany. It is a right tributary of the Rhume. Its source is in the Harz mountains, near Sankt Andreasberg. It flows southwest through Bad Lauterberg, Pöhlde and Hattorf am Harz...
and bringing it to St. Andreasberg. This was initially a great improvement in the supply of water power for the mines there, but the Oder could still not deliver enough water during a period of extended drought. So the call for a water reservoir quickly became shrill.
A glance at the Upper Harz 'ponds' (Teiche) near Clausthal-Zellerfeld and Hahnenklee suggested a solution. At that time there must have been 50 to 60 small reservoirs in operation. Their design, however, could not simply be copied, because there was nowhere in the vicinity of the Oderteich to cut grass sods like those used to seal the dams of the Upper Harz reservoirs.
In the meantime, the Rehberg Ditch, which had initially only been made of wooden channels (Holzgefludern), was being 'walled'; in other words the wooden conduits were being replaced by a considerably more durable artificial ditch made of earth embankments and dry stone walls. In doing so it was realised that the sand resulting from the weathering of granite, so-called granitgrus, if it was thoroughly tramped down, produced a very good seal.
In 1712, the deputy chief miner (Vizebergmeister), Caspar Dannenberger, wrote two letters to the Clausthal Mining Office, in which he proposed the construction of the Oderteich dam, sealed with granitic sand, as well as two embankments made of granite blocks. This proposal was duly taken up, but Caspar Dannenberger, the father of the Oderteich dams, did not survive to see it completed. He died on23 April 1713.
Planning was carried out in 1714 and, on 14 September, King George Louis
George I of Great Britain
George I was King of Great Britain and Ireland from 1 August 1714 until his death, and ruler of the Duchy and Electorate of Brunswick-Lüneburg in the Holy Roman Empire from 1698....
authorised the construction of the Oderteich dam in a most gracious special decree and made the available the sum estimated for the project: a total of 3048 thaler
Thaler
The Thaler was a silver coin used throughout Europe for almost four hundred years. Its name lives on in various currencies as the dollar or tolar. Etymologically, "Thaler" is an abbreviation of "Joachimsthaler", a coin type from the city of Joachimsthal in Bohemia, where some of the first such...
s and 27 gl.
The construction phase actually started in early 1715. Initially a core trench was excavated into which the dam was embedded. The building material for this was excavated from the land earmarked for the future reservoir. Granite blocks needed for the up- and downstream sides of the dam were cut from small quarries; this also provided a supply of granitic sand. The mining of material for the dam enabled the future reservoir capacity to be further enlarged.
The work took until 1722. Because excess water could neither be drained through the relatively small bottom outlet during the construction period nor be impounded, a spillway
Spillway
A spillway is a structure used to provide the controlled release of flows from a dam or levee into a downstream area, typically being the river that was dammed. In the UK they may be known as overflow channels. Spillways release floods so that the water does not overtop and damage or even destroy...
had to be continuously available whilst the dam was being built. This spillway had to be laid higher and higher as the dam grew in size.
Shortly after work on the dam had started there were discussions about raising it even higher than originally planned. In 1717 it was agreed to increase its height from the initial seven Lachter
Lachter
The Lachter was a common unit of length used in the mining industry in Europe, usually to measure depth, tunnel driving and the size of mining fields; it was also used for contract work...
to nine Lachter (roughly equating to just under 18 metres). This resulted in an increase in the dam volume of around 55 percent and a doubling of the reservoir capacity to 1.67 million cubic metres.
The cost of construction rose considerably during the build phase, not just as a result of the increase in dam height, but also other factors: in the end the Oderteich dam cost around 11,700 Reichstalers, almost four times the originally estimated and approved cost. Because the structure was so convincing, however, subsequent requests and approvals for the additional extra funding were not a problem. The three chief miners (Bergmeister) and excavation engineers (Grabensteiger) were rewarded in 1724 with bonuses ranging from 12 to 100 Talers.
The Sankt Andreasberg mine ground to a standstill in 1913. From then on the water of the Oderteich was used to generate electricity instead. It was now routed to Sankt Andreasberg itself, where it was used in several power stations and especially the Samson Pit. The water is still used for this purpose today and guarantees the economic operation and maintenance of the Oderteich and Rehberg Ditch.
In the late 1920s the Harzwasserwerke
Harzwasserwerke
The Harzwasserwerke is a German water company and dam operator with the primary tasks of supplying drinking water, generating electrical power, flood protection and the maintenance of the Upper Harz Water Regale...
planned a further significant increase in the height of the Oderteich Dam. The dam and the geology of the surrounding area were thoroughly examined. Digging exposed the seal of granitgrus and it was confirmed that this could not easily be worked with clay picks. These plans were later shelved for reasons that are not clear, although it is likely that the project was not seen as economical.
Design
The dam on the Oderteich differs considerably from the other dams in the Upper Harz Water Regale. The structure is clearly higher and the reservoir capacity just under three times the volume of the largest ponds around Clausthal-Zellerfeld and Hahnenklee. In addition completely different construction materials were employed.Dam structure
In the middle of the dam is a core, up to 11.5 metres thick, made of firmly tamped down, granitic sand. Left and right of that apparently 'normal' dam fill material was used. The up- and downstream sides were given cyclopean stonework wallsCyclopean masonry
Cyclopean masonry is a type of stonework found in Mycenaean architecture, built with huge limestone boulders, roughly fitted together with minimal clearance between adjacent stones and no use of mortar...
made of large blocks of granite with a slope of 1:0.5. On the downstream side the dam measures about from its base.
The dam wall has proved to be a very durable structure and, like the entire reservoir, is still virtually in its original condition.
Fundamentally it is not quite clear whether the Oderteich dam structure is an earth-fill dam or a masonry dam
Masonry dam
Masonry dams are dams made out of masonry; mainly stone and brick. They are either the gravity or the arch type.The largest masonry dam of the world is Nagarjunasagar Dam in India....
. It is probably a combination of the two.
Outlet
The tendency, for the Oderteich to use particularly long-lasting materials is best demonstrated in the design of the bottom outlet. At the lowest point in the valley a shaft was let into the dam, that had a cross-section of about 1.10 x 1.20 m. This shaft is edged with large, hewn granite blocks and descends to the natural floor of the valley. From the bottom of the shaft runs a tunnel, 0.75 metres wide and 0.90 metres high into the reservoir. This tunnel enables the water in the reservoir to equalise with the water level in the shaft. From the bottom of the shaft two wooden chutes (Holzgerenne) lead to the downstream side of the dam base. These chutes, made of oak, have a right-angled cross-section of about 25 x 25 cm and feature a valve on the bottom of the shaft that operates in a similar way to the type of bathplug that is closed from below. This valve can be pushed up or pulled shut using a rod operated from the control hut or Striegelhaus positioned above the shaft. The oak chute is designed in such as way that, even when the valve is shut, it remains submerged in water and so does not rot. This explains why the oak chutes fitted in 1715 are still being used. The entire bottom outlet design is known in the Upper Harz as a Striegel.Spillway
Every reservoir needs a spillwaySpillway
A spillway is a structure used to provide the controlled release of flows from a dam or levee into a downstream area, typically being the river that was dammed. In the UK they may be known as overflow channels. Spillways release floods so that the water does not overtop and damage or even destroy...
which ensures that even under conditions of exceptionally high water, the water does not rise to an uncontrollably high level, possibly even pouring over the dam crest. On the Oderteich the spillway is located at the left hand (eastern) end of the dam.
In the reservoir in front of the outlet are several stone columns, like standing stones
Menhir
A menhir is a large upright standing stone. Menhirs may be found singly as monoliths, or as part of a group of similar stones. Their size can vary considerably; but their shape is generally uneven and squared, often tapering towards the top...
in appearance, about 2.50 metres high and made of granite. They serve to keep ice floes away from the spillway, because these could jam the channel. The old outlet is clearly identifiable by a weir, which was built in 1895 by the Royal Central Smithy in Clausthal Königlichen Centralschmiede Clausthal. This weir enables the maximum storage level to be raised by a metre or so.
Originally the spillway ran for almost a 100 metres in a straight line southwards before the water dropped into the valley. This course is still visible in the terrain to the experienced eye. But when towards the end of the construction phase in there were still not enough stones to complete the dam wall, a steep, 80 metre-long Große Ausflut ("large spillway") was blasted out of the rock roughly 60 metres below the weir at right angles to the original spillway. Perhaps it was hoped that this would increase the hydraulic capacity
Volumetric flow rate
The volumetric flow rate in fluid dynamics and hydrometry, is the volume of fluid which passes through a given surface per unit time...
of the outlet. The channel carved out of the rock is very impressive especially on the spillway.
To begin with the spillway was not large enough: in December 1760 water overspilled the dam during a period of exceptional high water. Damage was limited, which said something, especially about the stable design of the dam. In response to this incident the dam was raised by about a metre, which has probably merely compensated for the subsidence of the dam since that time.
In 1886/87, however it appears that the conclusion was reached that the capacity of the spillway needed to be increased. To achieve this another spillway was built a few metres east of the existing one. It had an inlet breadth of 12 metres and its crest was about a metre higher than that of the old, main spillway. This outlet crosses under the B 242 parallel to the main one and merges with the main spillway shortly before the high water marker and its adjoining chute (Schussrinne). This additional spillway enables the discharge capacity during times of flood to be increased by about 50 %.
Coffer dam in the reservoir
When the Oderteich is fully emptied the remains of coffer dam can be seen about 200 metres above the main dam. This was built in 1898 when the Oderteich Reservoir was empty in order to reduce the water flow whilst repairs were carried out to the bottom outlet. The coffer dam must have been demolished immediately after this repair had been completed.Capacity
As a result of the use of water for electricity generation the Rehberg Ditch drew 200 to 300 litres of water per second continuously from the Oderteich. When the inflow of water is less than its outflow, the water level in the reservoir drops. If there are several months of drought in succession, the reservoir can become empty. This happens about every five to ten years, the last occasions being in 1991, 1999 and 2003.The surcharge capacity of the Oderteich is very small. Its reservoir can only store 14 % of its annual discharge. This results in unusually high fluctuations in the water level of the reservoir, which can even change from being largely empty to overflowing within a few hours. This explains why the Oderteich overflows several times a year.
Water quality
There is no fishway at the Oderteich. The relatively acidic condition of the water is probably not a good habitat for fish. Most of the water comes from areas of raised bog and is rich in humic acidHumic acid
Humic acid is a principal component of humic substances, which are the major organic constituents of soil , peat, coal, many upland streams, dystrophic lakes, and ocean water. It is produced by biodegradation of dead organic matter...
. Humic acid also causes its brown coloration. In addition, it reduces surface tension
Surface tension
Surface tension is a property of the surface of a liquid that allows it to resist an external force. It is revealed, for example, in floating of some objects on the surface of water, even though they are denser than water, and in the ability of some insects to run on the water surface...
, something which causes conspicuous white horses such as occur in the turbulence at the intakes and outlets of the reservoir.
Largest dam in Germany
The Oderteich is frequently reported as the "oldest dam and reservoir in Germany". This accolade is disputed, however, because in the early 18th century in the area of Clausthal-Zellerfeld, Buntenbock and Hahnenklee there was already a large number of 'reservoirs' (Talsperren) as defined by the German industrial normDin
DIN or Din or din can have several meanings:* A din is a loud noise.* Dīn, an Arabic term meaning "religion" or "way of life".* Din is one of the ten aspects of the Ein Sof in Kabbalah ....
, DIN 19700-11. What is true is that from its completion in 1722 to the end of the 19th century, a period of 170 years, it had the largest dam in Germany. Not until the Eschbach Dam in the Bergisches Land
Bergisches Land
The Bergisches Land is a low mountain range region within the state of Nordrhein-Westfalen, Germany, east of Rhine river, south of the Ruhr. The landscape is shaped by woods, meadows, rivers and creeks and contains over 20 artificial lakes...
was finished in 1891 with a height of was there a higher dam than the Oderteich.
Waterside footpath
In the middle of the 1990s, the operators of the Oderteich, the HarzwasserwerkeHarzwasserwerke
The Harzwasserwerke is a German water company and dam operator with the primary tasks of supplying drinking water, generating electrical power, flood protection and the maintenance of the Upper Harz Water Regale...
, laid out a waterside footpath (the WasserWanderWeg) as an educational trail. This runs along the dam crest to the two spillways, past the two additional basins and via the overspill marker then downhill alongside the Großer Ausflut and its chute to the downstream foot of the dam, from where there is an impressive view of the stonework on this side of the dam and where the bottom outlet and start of the Rehberg Ditch can be seen. Information boards along the path explain the various structures.
Other recreational uses
The Oderteich lies in the centre of the Harz National ParkHarz National Park
The Harz National Park is a nature reserve in the German federal states of Lower Saxony and Saxony-Anhalt. It comprises large portions of the western Harz mountain range, extending from Herzberg and Bad Lauterberg at the southern edge to Bad Harzburg and Ilsenburg on the northern slopes...
. Swimming is allowed in the southern third of the reservoir and in the vicinity of the dam. The northern area is barred to swimmers in the summer by a chain and is meant to be exclusively reserved as a biotope
Biotope
Biotope is an area of uniform environmental conditions providing a living place for a specific assemblage of plants and animals. Biotope is almost synonymous with the term habitat, but while the subject of a habitat is a species or a population, the subject of a biotope is a biological community.It...
. There is a roughly 4.5 km long circular walk around the reservoir, for which good walking boots are recommended. This path is routed along board walks in places because of the terrain which resembles that of a raised bog.
Winter sports, such as skating, on the reservoir in winter are not recommended, because the large variations in the water level make the formation of a stable ice surface difficult, especially near the shores.