The Oker () is a

river A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of ...

Lower Saxony Lower Saxony is a States of Germany, German state (') in Northern Germany, northwestern Germany. It is the second-largest state by land area, with , and fourth-largest in population (8 million in 2021) among the 16 ' of the Germany, Federal Re ...

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

, 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's name was recorded around 830 as ''Obacra'' and, later, as ''Ovokare'' und ''Ovakara''.H. Blume: ''Oker, Schunter, Wabe.'' In: ''Braunschweigisches Jahrbuch für Landesgeschichte'', vol. 86, 2005, p. 14 sqq. The origin of the name is derived from the

root In vascular plants, the roots are the plant organ, organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often bel ...

s ''ov-'' and ''-akara'' meaning “upper” (cf.

New High German New High German (NHG; ) is the term used for the most recent period in the history of the German language, starting in the 17th century. It is a loan translation of the German (). The most important characteristic of the period is the developme ...

''ober-'') and “onward rushing” (rendered in German as “Vorwärtsdrängende”) as distinct from its tributary, the Ecker, whose name means only “onward rushing”.

Course

The Oker rises at about 910 metres in the

Harz National Park Harz National Park is a nature reserve in the Germany, German federal states of Lower Saxony and Saxony-Anhalt. It comprises portions of the western Harz mountain range, extending from Herzberg am Harz, Herzberg and Bad Lauterberg at the southern ...

in a boggy area on 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 ...

in the

Harz The Harz (), also called the Harz Mountains, 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'' der ...

mountains of central Germany. This early section is known as the ''Große Oker'' ("Great Oker") and it is impounded below

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 ...

by the

Oker Dam The Oker Dam () is a dam in the Harz mountains in Lower Saxony, Germany. It is fed by the River Oker. Technology The dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dam ...

. From the dam wall to the former village of

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 ...

, which is today part of

Goslar Goslar (; Eastphalian dialect, Eastphalian: ''Goslär'') is a historic town in Lower Saxony, Germany. It is the administrative centre of the Goslar (district), district of Goslar and is located on the northwestern wikt:slope, slopes of the Harz ...

, the Oker is on certain occasions suitable for

canoeing Canoeing is an activity which involves paddling a canoe with a single-bladed paddle. In some parts of Europe, canoeing refers to both canoeing and kayaking, with a canoe being called an 'open canoe' or Canadian. A few of the recreational ...

. This section, often called the "Oker Valley" (''Okertal''), includes the Romkerhall Waterfall. Here the ''Romke'' stream drops about in height over a

waterfall A waterfall is any point in a river or stream where water flows over a vertical drop or a series of steep drops. Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf. Waterfalls can be formed in seve ...

laid out in 1863 into the Oker. Downstream in the river's fast-flowing waters, the ''Verlobungsinsel'' ("Betrothal Island") is to be found. Left and right of the Oker in this area are many

crag Crag may refer to: * Crag (climbing), a cliff or group of cliffs, in any location, which is or may be suitable for climbing * Crag (dice game), a dice game played with three dice * Crag, Arizona, US * Crag, West Virginia, US * Crag and tail, a ...

s that are popular with climbers. In the Goslar vicinity of Oker the river is seriously polluted with heavy metals from the

slag heap A spoil tip (also called a boney pile, culm bank, gob pile, waste tip or bing) is a pile built of accumulated ''spoil'' – waste material removed during mining. Spoil tips are not formed of slag, but in some areas, such as England and Wales, ...

s as well as

groundwater Groundwater is the water present beneath Earth's surface in rock and Pore space in soil, soil pore spaces and in the fractures of stratum, rock formations. About 30 percent of all readily available fresh water in the world is groundwater. A unit ...

and

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 ...

from the metal

smelter Smelting is a process of applying heat and a chemical reducing agent to an ore to extract a desired base metal product. It is a form of extractive metallurgy that is used to obtain many metals such as iron, copper, silver, tin, lead and zin ...

s there.

From the village of Oker the River Oker flows away in a northeasterly direction to

Vienenburg Vienenburg is a borough of Goslar, capital of the Goslar district, in Lower Saxony, Germany. The former independent municipality was incorporated in Goslar on 1 January 2014. Geography It is situated in the north of the Harz mountain range and eas ...

, where it is joined from the south by the Radau and then from the southeast by the Ecker. After these two confluences the river continues southeast past the Harly Forest, after which it bends north to flow through

Schladen Schladen is a village and a former municipality in the district of Wolfenbüttel, in Lower Saxony, Germany. Since 1 November 2013, it is part of the municipality Schladen-Werla. It is situated on the river Oker, approx. 15 km south of Wolfen ...

and

Wolfenbüttel Wolfenbüttel (; ) is a town in Lower Saxony, Germany, the administrative capital of Wolfenbüttel District Wolfenbüttel (; ) is a town in Lower Saxony, Germany, the administrative capital of Wolfenbüttel (district), Wolfenbüttel Distri ...

Braunschweig Braunschweig () or Brunswick ( ; from Low German , local dialect: ) is a List of cities and towns in Germany, city in Lower Saxony, Germany, north of the Harz Mountains at the farthest navigable point of the river Oker, which connects it to the ...

. In south Braunschweig the Oker is dammed by the Eisenbüttel Weir. In the ''Bürgerpark'' shortly before Braunschweig's

old town In a city or town, the old town is its historic or original core. Although the city is usually larger in its present form, many cities have redesignated this part of the city to commemorate its origins. In some cases, newer developments on t ...

the Oker divides into the western and eastern bypass channels (''Umflutgraben'') which circumnavigate the historic city centre at a slightly higher level. These channels were laid in the 16th century as the external moats of the town's defences. The actual course of the Oker through the centre of the town was covered and, today, runs through pipes emerging again north of the old town. The water level in the city area is controlled by the St. Peter's Gate Weir (''Petritorwehr'') in the western and the "

Wends Wends is a historical name for Slavs who inhabited present-day northeast Germany. It refers not to a homogeneous people, but to various people, tribes or groups depending on where and when it was used. In the modern day, communities identifying ...

Weir" (''Wendenwehr'') in the eastern ditch. Following the merger of the two channels northwest of the city centre the Oker runs north of the district of in a

culvert A culvert is a structure that channels water past an obstacle or to a subterranean waterway. Typically embedded so as to be surrounded by soil, a culvert may be made from a pipe (fluid conveyance), pipe, reinforced concrete or other materia ...

under the

Mittelland Canal The Mittelland Canal, also known as the Midland Canal, (, ) is a major canal in central Germany. It forms an important link in the waterway network of the country, providing the principal east-west inland waterway connection. Its significanc ...

before it is joined by the

Schunter Schunter () is a river in Lower Saxony, Germany. It has a length of and is a right tributary of the Oker. Etymology The river was first mentioned as ''Schuntra'' in a 781 deed. The name may be of Slavic languages, Slavic origin as ''sukątora'' ...

from the east near Groß Schwülper. It then flows down to its mouth into the River Aller, which is located between

Gifhorn Gifhorn () is a town and capital of the district of Gifhorn (district), Gifhorn in the east of Lower Saxony, Germany. It has a population of about 42,000 and is mainly influenced by the small distance to the more industrial and commercially import ...

and

Celle Celle () is a town and capital of the district of Celle (district), Celle in Lower Saxony, in north-central Germany. The town is situated on the banks of the river Aller (Germany), Aller, a tributary of the Weser, and has a population of about ...

at Müden.

The Oker as border river

Since the early ninth century the middle Oker river has formed the

diocesan In church governance, a diocese or bishopric is the ecclesiastical district under the jurisdiction of a bishop. History In the later organization of the Roman Empire, the increasingly subdivided provinces were administratively associated ...

boundary between the bishoprics of Halberstadt and

Hildesheim Hildesheim (; or ; ) is a city in Lower Saxony, in north-central Germany with 101,693 inhabitants. It is in the district of Hildesheim (district), Hildesheim, about southeast of Hanover on the banks of the Innerste River, a small tributary of t ...

, established by Emperor

Charlemagne Charlemagne ( ; 2 April 748 – 28 January 814) was List of Frankish kings, King of the Franks from 768, List of kings of the Lombards, King of the Lombards from 774, and Holy Roman Emperor, Emperor of what is now known as the Carolingian ...

and his son

Louis the Pious Louis the Pious (; ; ; 16 April 778 – 20 June 840), also called the Fair and the Debonaire, was King of the Franks and Holy Roman Emperor, co-emperor with his father, Charlemagne, from 813. He was also King of Aquitaine from 781. As the only ...

in the

Duchy of Saxony The Duchy of Saxony () was originally the area settled by the Saxons in the late Early Middle Ages, when they were subdued by Charlemagne during the Saxon Wars from 772 CE and incorporated into the Carolingian Empire (Francia) by 804. Upon the 84 ...

. North of Schladen the royal palace (''

Königspfalz The term ''Kaiserpfalz'' (, "imperial palace") or ''Königspfalz'' (, "royal palace", from Middle High German ''phal ne'' to Old High German ''phalanza'' from Middle Latin ''palatia'' luralto Latin ''palatium'' "palace") refers to a num ...

'') of Werla was established on the banks about above the river bed. From the High Middle Ages the Oker between the villages of Ohrum and Börßum formed the eastern boundary of the Prince-Bishopric of Hildesheim with the Duchy of Brunswick-Wolfenbüttel, and further south to Wiedelah (today part of

) with the Prince-Bishopric of Halberstadt, which became the Prussian

Principality of Halberstadt The Principality of Halberstadt () was a state of the Holy Roman Empire ruled by Brandenburg-Prussia. It replaced the Bishopric of Halberstadt after its secularization in 1648. Its capital was Halberstadt. In 1807, the principality was made a ...

following its

secularization In sociology, secularization () is a multilayered concept that generally denotes "a transition from a religious to a more worldly level." There are many types of secularization and most do not lead to atheism or irreligion, nor are they automatica ...

in 1648. The Bishopric of Halberstadt was likewise mediatised in 1803, and according to the Final Act of the 1815

Vienna Congress The Congress of Vienna of 1814–1815 was a series of international diplomatic meetings to discuss and agree upon a possible new layout of the European political and constitutional order after the downfall of the French Emperor Napoleon, Napol ...

, the Oker was the eastern border of the

Kingdom of Hanover The Kingdom of Hanover () was established in October 1814 by the Congress of Vienna, with the restoration of George III to his Hanoverian territories after the Napoleonic Wars, Napoleonic era. It succeeded the former Electorate of Hanover, and j ...

with the

Duchy of Brunswick The Duchy of Brunswick () was a historical German state that ceased to exist in 1918. Its capital city, capital was the city of Braunschweig, Brunswick (). It was established as the successor state of the Principality of Brunswick-Wolfenbüttel ...

and the Prussian

Province of Saxony The Province of Saxony (), also known as Prussian Saxony (), was a province of the Kingdom of Prussia and later the Free State of Prussia from 1816 until 1944. Its capital was Magdeburg. It was formed by the merger of various territories ceded ...

. When the

Kingdom of Prussia The Kingdom of Prussia (, ) was a German state that existed from 1701 to 1918.Marriott, J. A. R., and Charles Grant Robertson. ''The Evolution of Prussia, the Making of an Empire''. Rev. ed. Oxford: Clarendon Press, 1946. It played a signif ...

annexed Hanover in 1866, it became the inner Prussian border between the provinces of Hanover and

Saxony Saxony, officially the Free State of Saxony, is a landlocked state of Germany, bordering the states of Brandenburg, Saxony-Anhalt, Thuringia, and Bavaria, as well as the countries of Poland and the Czech Republic. Its capital is Dresden, and ...

as well as the border, north of Börßum to Ohrum between the Province of Hanover in the west and the Duchy of Brunswick in the east. From 1945 to 1990 the

Inner German border The inner German border ( or ''deutsch–deutsche Grenze''; initially also , zonal boundary) was the frontier between the East Germany, German Democratic Republic (GDR, East Germany) and the West Germany, Federal Republic of Germany (FRG, West ...

between

East East is one of the four cardinal directions or points of the compass. It is the opposite direction from west and is the direction from which the Sun rises on the Earth. Etymology As in other languages, the word is formed from the fact that ea ...

and

West Germany West Germany was the common English name for the Federal Republic of Germany (FRG) from its formation on 23 May 1949 until German reunification, its reunification with East Germany on 3 October 1990. It is sometimes known as the Bonn Republi ...

ran down the centre of the Oker between Wiedelah and Schladen, today between the German

states State most commonly refers to: * State (polity), a centralized political organization that regulates law and society within a territory **Sovereign state, a sovereign polity in international law, commonly referred to as a country **Nation state, a ...

Saxony-Anhalt Saxony-Anhalt ( ; ) is a States of Germany, state of Germany, bordering the states of Brandenburg, Saxony, Thuringia and Lower Saxony. It covers an area of and has a population of 2.17 million inhabitants, making it the List of German states ...

and

. Since the

Expo 2000 Expo 2000 was a World Expo held in Hanover, Germany from 1 June to 31 October 2000. It was located on the Hanover Fairground (Messegelände Hannover), which is the largest exhibition ground in the world. Initially, some 40 million people were ...

bridges over the Oker in Braunschweig and its surrounding area were artistically designed; after 2004 this was carried out as part of the ''Okerlicht'' project.

Tributaries

References

External links

Heavy metal pollution of the Oker

Description of white water canoe section between Kraftwerk and Nachstaubecken with many photos