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31-543: The district was created in 1973 by merging the districts of Kehl, Lahr, Offenburg, Wolfach and the southern part of the district of Bühl. The western part of the district is located in the Upper Rhine Valley, the eastern part belongs to the northern Black Forest . The highest elevation of the district, the Hornisgrinde (1164 m), is located in the north-east of the district. The lowest elevation (124.3 m)

62-546: A 200-year flood (i.e. a flood that statistically occurs once in 200 years) of the Rhine to a discharge of 5,000 cubic metres per second (180,000 cu ft/s) at the Maxau gauge station, that is, a reduction from 5,700 cubic metres per second (200,000 cu ft/s) to 5,000 cubic metres per second (180,000 cu ft/s). For this purpose the following measures are planned and partially implemented: The effectiveness of

93-503: A fault breaks into two strands, or two faults run close to each other, crustal extension may also occur between them, as a result of differences in their motions. Both types of fault-caused extension commonly occur on a small scale, producing such features as sag ponds or landslides . Many of the world's largest lakes are located in rift valleys. Lake Baikal in Siberia , a World Heritage Site , lies in an active rift valley. Baikal

124-670: A part of the western Eistla, and possibly also Alta and Bell Regio have been interpreted by some planetary geologists as rift valleys. Some natural satellites also have prominent rift valleys. The 2,000 km long Ithaca Chasma on Tethys in the Saturn system is a prominent example. Charon's Nostromo Chasma is the first confirmed in the Pluto system, however large chasms up to 950 km wide observed on Charon have also been tentatively interpreted by some as giant rifts, and similar formations have also been noted on Pluto. A recent study suggests

155-499: A rift valley called the Ottawa-Bonnechere Graben . Þingvallavatn , Iceland's largest natural lake, is also an example of a rift lake. Rift valleys are also known to occur on other terrestrial planets and natural satellites. The 4,000 km long Valles Marineris on Mars is believed by planetary geologists to be a large rift system. Some features of Venus, most notably, the 4,000 km Devana Chasma and

186-414: Is a linear shaped lowland between several highlands or mountain ranges produced by the action of a geologic rift . Rifts are formed as a result of the pulling apart of the lithosphere due to extensional tectonics . The linear depression may subsequently be further deepened by the forces of erosion. More generally the valley is likely to be filled with sedimentary deposits derived from the rift flanks and

217-729: Is both the deepest lake in the world and, with 20% of all of the liquid freshwater on earth, has the greatest volume. Lake Tanganyika , second by both measures, is in the Albertine Rift , the westernmost arm of the active East African Rift . Lake Superior in North America , the largest freshwater lake by area, lies in the ancient and dormant Midcontinent Rift . The largest subglacial lake, Lake Vostok , may also lie in an ancient rift valley. Lake Nipissing and Lake Timiskaming in Ontario and Quebec , Canada lie inside

248-744: Is in the Rhine valley to the north. The district is named after the historical territory of the Ortenau . The district has a friendship with the Altenburger Land district in Thuringia . Offenburg district already had a city partnership with Altenburg so, after German reunification in 1990, Ortenaukreis chose to help modernize the Altenburger Land administration to the West German standard. France and Germany have created

279-732: The East African Rift , Rio Grande rift and the Baikal Rift Zone , which are currently active, as well as a fourth which may be, the West Antarctic Rift System . In these instances, not only the crust but entire tectonic plates are in the process of breaking apart forming new plates. If they continue, continental rifts will eventually become oceanic rifts. Other rift valleys are the result of bends or discontinuities in horizontally-moving (strike-slip) faults. When these bends or discontinuities are in

310-608: The Grand Canal d'Alsace on the French side, to ensure safe shipping and hydropower generation around the clock. Only when there is a large supply of water, then the old river bed will receive more water than the canal. France gained the right to do this in the 1919 Treaty of Versailles; the right applies to the segment between Basel and Neuburgweier /Lauterbourg, where the Rhine forms the border between France and Germany. The straightening (1817–76) and channeling (1928–77) reduced

341-509: The Grand Canal d'Alsace . On the left bank are the French region of Alsace and the German state of Rhineland-Palatinate; on the right bank are the German states of Baden-Württemberg and Hesse. The first few kilometres are in the Swiss city of Basel. Around 35 million years ago, a rift valley of about 300 kilometres (190 mi) long and 50 kilometres (31 mi) wide came into being between

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372-542: The Integrated Rhine Programme , a framework for designating water retention areas. to combat downstream flooding. A French-German treaty was concluded in 1982, in which the parties agreed to restore the retention capacity on the stretch below Iffezheim to the level it had before the area was developed. This means: For the stretch between Iffezheim and the mouth of the Neckar, attenuation of the apex of

403-531: The Old Rhine ( Alter Rhein ) in the Alpine Rhine Valley , where the Rhine was also straightened). The Rhine between Basel and Iffezheim is almost entirely canalised. On a stretch of 180 kilometres (110 mi), there are 10 dams , provided with hydropower stations and locks . Between Basel and Breisach , the old river bed carries hardly any water; almost all water is diverted through

434-619: The Pylon , is located 160 m (520 ft) southeast of the actual tripoint. In 1685, Louis XIV started a project to move the Upper Rhine, change its course and drain the floodplain , in order to gain land. By 1840, the river had been moved up to 1.5 kilometres (0.93 mi) to the east, taking territory away from Baden. Around 1790, large parts of the Rhine Valley were deforested, creating arable land, fields and pasture to feed

465-776: The Rhine knee in Bingen , Germany . It is surrounded by the Upper Rhine Plain ( Oberrheinische Tiefebene ). Most of its upper section marks the France–Germany border . The Upper Rhine is one of four sections of the river (the others being the High Rhine , Middle Rhine and Lower Rhine ) between Lake Constance and the North Sea. The countries and states along the Upper Rhine are Switzerland, France ( Alsace ) and

496-642: The Strasbourg-Ortenau eurodistrict straddling the Rhine and combining Ortenaukreis and Greater Strasbourg , with an overall population of 950,000. The coat of arms is identical with that of the former Offenburg, and is based on the coat of arms of the Ortenau canton of the League of Imperial Knights . It shows an imperial eagle with two heads, which also stands for the free imperial cities of Offenburg , Gengenbach and Zell . In an escutcheon on

527-685: The Tertiary , the High Rhine continued west from Basel and flowed via the Doubs and the Saône , into the Rhône . The rift diverted the Rhine into the newly formed Upper Rhine Valley . The Rhine knee at Basel marks the transition from the High Rhine to the Upper Rhine with a change of direction from West to North and a change of landscape from the relatively small-chamber high-Rhine cuesta landscape to

558-406: The water table by up to 16 metres (52 ft) and thus had a negative effect on flora and fauna . Gravel is also missing from the river, due to the dams. This has caused erosion below the dam at Iffezheim. To counter this, 173,000 cubic metres (6,100,000 cu ft) per year of a mixture of sand and gravel with an average grain diameter of 20 millimetres (0.79 in) (corresponding to

589-423: The German states of Baden-Württemberg , Rhineland-Palatinate and Hesse . The largest cities along the river are Basel, Mulhouse , Strasbourg , Karlsruhe , Mannheim , Ludwigshafen and Mainz . The Upper Rhine was straightened between 1817 and 1876 by Johann Gottfried Tulla and made navigable between 1928 and 1977. The Treaty of Versailles allows France to use the Upper Rhine for hydroelectricity in

620-458: The High Rhine. As the name suggests, it is a tri-national region comprising parts of France, Germany and Switzerland. The regional Upper Rhine Conference is a framework for future political and administrative cooperation in the area. The tripoint between France, Germany and Switzerland, called Dreiländereck , lies within the uppermost portion of the Upper Rhine. A monument in Basel, known as

651-557: The Rhine. The implementation of the proposed flood control measures on the Upper Rhine can prevent the occurrence of a 200-year-flood between Iffezheim and Bingen, with an overall economic loss estimated at around 6.2 billion euros. The floodplains between Mainz and Bingen are important for nature conservation. In this section, the so-called Island Rhine , there are many nature reserves and bird sanctuaries . 48°57′N 8°16′E  /  48.950°N 8.267°E  / 48.950; 8.267 Rift valley A rift valley

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682-610: The breast of the eagle is the patron Saint George , depicted killing the dragon. 48°25′N 8°00′E  /  48.417°N 8.000°E  / 48.417; 8.000 Upper Rhine The Upper Rhine ( German : Oberrhein [ˈoːbɐˌʁaɪn] ; French : Rhin Supérieur ; kilometres 167 to 529 of the Rhine ) is the section of the Rhine between the Middle Bridge in Basel , Switzerland , and

713-569: The flood protection measures was verified using a computer model. The State Institute for the Environment, Nature Protection and Measurements in Baden-Württemberg carried out forecast calculations with the help of a mathematical "synoptic flood progression model". The analysis of the calculations and the evaluation of the results were made on the basis of the requirements and methods set by the international Flood Study Commission for

744-785: The local sediment transport capacity) has been dumped into the river, since 1978, using two motorized barges. The Upper Rhine plays a key role in flood control on the Middle and Lower Rhine . As a result of the straightening of the Upper Rhine, floods from the Alps now reach the Middle Rhine much faster than in the past. Thus, the risk of such a peak coinciding with a flood peak of Neckar, Moselle or Main has increased. About 123 square kilometres (47 sq mi) of floodplain have been lost. Authorities in riparian states of France, Baden-Württemberg and Rhineland-Palatinate have launched

775-509: The nearest settlement to their confluence given in brackets. Left tributaties : Right tributaries : The Upper Rhine tri-national region (French: Région Métropolitaine Trinationale du Rhin Supérieur , German: Trinationale Metropolregion Oberrhein ) is a Euroregion that covers the border areas of the Upper Rhine (the northern part of the Upper Rhine valley and the Palatinate are not included as they are not border areas) and parts of

806-459: The population. The Upper Rhine was straightened between 1817 and 1876 by Johann Gottfried Tulla and changed from a relatively sluggish meandering river with major and many smaller branches into a fast flowing stream flanked by embankments. The length of the Upper Rhine was reduced by 81 kilometres (50 mi). Some cut-off river arms and ox-bows remain; they are typically called the 'Old Rhine' ( German : Altrhein ) or Gießen (similar to

837-593: The present cities of Basel and Frankfurt . This was due to tensile stresses in the Earth's crust and mantle , which resulted in lowering the earth's surface. The moat has been partially filled up again by sedimentation . On the edges we find mountain ridges, the so-called "rift flanks". On the eastern side, they are the Black Forest and Odenwald mountains, in the west the Vosges and Palatinate Forest . During

868-539: The principal rift valley geologically. The most extensive rift valley is located along the crest of the mid-ocean ridge system and is the result of sea floor spreading . Examples of this type of rift include the Mid-Atlantic Ridge and the East Pacific Rise . Many existing continental rift valleys are the result of a failed arm ( aulacogen ) of a triple junction , although there are three,

899-460: The same direction as the relative motions along the fault, extension occurs. For example, for a right lateral-moving fault, a bend to the right will result in stretching and consequent subsidence in the area of the irregularity. In the view of many geologists today, the Dead Sea lies in a rift which results from a leftward discontinuity in the left lateral-moving Dead Sea Transform fault. Where

930-407: The surrounding areas. In many cases rift lakes are formed. One of the best known examples of this process is the East African Rift . On Earth, rifts can occur at all elevations, from the sea floor to plateaus and mountain ranges in continental crust or in oceanic crust . They are often associated with a number of adjoining subsidiary or co-extensive valleys, which are typically considered part of

961-934: The wide rift zone of the Upper Rhine Rift Valley. The two largest tributaries come from the right: the Neckar in Mannheim , the Main across from Mainz . In the northwest corner of the Upper Rhine Valley, at Rhine-kilometre 529.1, near Bingen, where the Nahe flows into the Rhine, the Rhine flows into a gorge in the Rhenish Massif and thereby changes into the Middle Rhine . Tributaries are listed in direction of flow (bottom to top), with

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