The main European watershed is the drainage divide ("watershed") which separates the basins of the rivers that empty into the Atlantic Ocean, the North Sea and the Baltic Sea from those that feed the Mediterranean Sea, the Adriatic Sea and the Black Sea. It stretches from the tip of the Iberian Peninsula at Gibraltar in the southwest to the endorheic basin of the Caspian Sea in Russia in the northeast.
The Watershed runs northwards through Spain in the Iberian Peninsula towards the Bay of Biscay along the basins of the Guadalquivir, [1] Guadiana, Tagus and Douro in the west to the sources of the Ebro in Cantabria. [2] [3] [4] [5] It then follows the main ridge of the Pyrenees eastwards up to Andorra, where it again turns to the north through France along the catchment areas of the Garonne (with the summit of the Canal du Midi at Seuil de Naurouze), Loire and Seine in the west and that of the Rhone in the east, marked by the Cévennes mountain range between the sources of the Allier and Ardèche tributaries. The European watershed meets the Atlantic-North Sea Continental Divide at the triple point between the Atlantic, North Sea and Mediterranean Sea at Mount Piémont in Northeast France. [6]
At the Belfort Gap south of the Vosges Mountains it separates the Rhone basin in the southwest from the drainage of the Meuse and Rhine in the northeast, turns southwards to the Swiss Jura Mountains and passes between Lake Geneva and Lake Neuchâtel. It reaches the Bernese Alps where it crosses the Jungfrau and the Finsteraarhorn, at 4,274 m the high point of the watershed, before dropping to the Grimselpass, rising to the Dammastock before crossing the Furkapass and joining the Alpine divide near the Witenwasserenstock, the triple watershed of the Rhone, Rhine and Po rivers. East of here it crosses the Gotthard Pass and runs along the Adula Alps until it reaches the triple point of the Rhine, Po and Danube basins at the "roof of Europe" near Piz Lunghin west of the Maloja Pass. [7]
The divide continues northwards along the Albula Alps to Julier Pass, Albula Pass and Flüela Pass south of Davos, between the catchment area of the Rhine, which empties into the North Sea via the Netherlands, and the Danube, which flows eastward emptying into the Black Sea. It enters Austria at Piz Buin in the Silvretta Alps, running along the Arlberg massif and forming the border between the states of Tyrol and Vorarlberg. It reaches Bavaria, Germany, via the crest of the Allgäu Alps and leaves the High Alps at the Adelegg range near Kempten. [7]
Within the Alpine foothills it runs north of the Schussen catchment area of Lake Constance towards the sources of the Brigach and Breg headwaters of the Danube in the Black Forest. It then follows the main ridge of the Swabian and Franconian Jura with the crossing of the Rhine–Main–Danube Canal northeastwards up to the Fichtel Mountains and southeastwards along the Bohemian Forest, forming the border between Germany and the Austrian Mühlviertel and Waldviertel regions with the Czech Republic, where the large Bohemian basin is drained by the Elbe River. [8] [9] It again turns northeastwards along the Javořice Highlands to the Králický Sněžník Mountains of the Eastern Sudetes at the border with Poland, where the triple point of the Orlice, Elbe (North Sea); Morava, Danube (Black Sea); and Eastern Neisse, Oder (Baltic Sea) is located at the peak of Klepáč (Trójmorski Wierch). At this point, the European Watershed connects to the North Sea–Baltic Sea Continental Divide. [10]
The Watershed continues in an eastern direction along the Jeseníky Mountains down to the Moravian Gate and uphill into the Beskids, with the Oder and Vistula basins in the north, reaching the triple point of Poland with Slovakia and Ukraine in the Bieszczady Mountains. [11] Then, the Watershed goes northeast near the Poland–Ukraine border, passes through the city of Lviv and, via Volyn, enters Belarus. Then it runs east-northeast along the Belarusian Ridge and continues to the Smolensk Oblast of Russia, ending at the triple point with the Caspian drainage basin in the Sychyovsky District, near the midpoint between the Western Russian cities of Smolensk and Tver. [12]
The watershed is not a clearly defined divide.
For example, tectonics in the area which is now the Upper Rhine Plain created the river Rhine. The Rhine's sharper altitude gradient on its much shorter way to the North Sea causes much stronger headward erosion than that of the much older River Danube (see the Danube upper river geology). Therefore the Rhine and its tributaries intrude deeper into phreatic zones of the Swabian Karst and even capture the upper Danube and its surface tributaries. [13] It is expected that the Danube's upper course will one day disappear entirely in favour of the Rhine ("stream capture").
The Rhine is one of the major European rivers. The river begins in the Swiss canton of Graubünden in the southeastern Swiss Alps. It forms part of the Swiss-Liechtenstein, Swiss-Austrian, and Swiss-German borders. After that the Rhine defines much of the Franco-German border, after which it flows in a mostly northerly direction through the German Rhineland. Finally in Germany, the Rhine turns into a predominantly westerly direction and flows into the Netherlands where it eventually empties into the North Sea. It drains an area of 9,973 km2 and its name derives from the Celtic Rēnos. There are also two German states named after the river, North Rhine-Westphalia and Rhineland-Palatinate.
Austria is a predominantly mountainous country in Central Europe, approximately between Germany, Italy and Hungary. It has a total area of 83,871 square kilometres (32,383 sq mi).
The main chain of the Alps, also called the Alpine divide is the central line of mountains that forms the drainage divide of the range. Main chains of mountain ranges are traditionally designated in this way, and generally include the highest peaks of a range. The Alps are something of an unusual case in that several significant groups of mountains are separated from the main chain by sizable distances. Among these groups are the Dauphine Alps, the Eastern and Western Graians, the entire Bernese Alps, the Tödi, Albula and Silvretta groups, the Ortler and Adamello ranges, and the Dolomites of South Tyrol, as well as the lower Alps of Vorarlberg, Bavaria, and Salzburg.
The Continental Divide of the Americas is the principal, and largely mountainous, hydrological divide of the Americas. The Continental Divide extends from the Bering Strait to the Strait of Magellan, and separates the watersheds that drain into the Pacific Ocean from those river systems that drain into the Atlantic and Arctic Ocean, including those that drain into the Gulf of Mexico, the Caribbean Sea, and Hudson Bay.
A drainage basin is an area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, the drainage divide, made up of a succession of elevated features, such as ridges and hills. A basin may consist of smaller basins that merge at river confluences, forming a hierarchical pattern.
The Eastern Continental Divide, Eastern Divide or Appalachian Divide is a hydrological divide in eastern North America that separates the easterly Atlantic Seaboard watershed from the westerly Gulf of Mexico watershed. The divide nearly spans the United States from south of Lake Ontario through the Florida peninsula, and consists of raised terrain including the Appalachian Mountains to the north, the southern Piedmont Plateau and lowland ridges in the Atlantic Coastal Plain to the south. Water including rainfall and snowfall, lakes, streams and rivers on the eastern/southern side of the divide drains to the Atlantic Ocean; water on the western/northern side of the divide drains to the Gulf of Mexico. The ECD is one of six continental hydrological divides of North America which define several drainage basins, each of which drains to a particular body of water.
The Julier Pass is a mountain pass in Switzerland, in the Albula Alps. It connects the Engadin valley with central Graubünden, the nearest inhabited localities on its approaches being Silvaplana and Bivio. At its summit, the pass crosses the watershed / drainage divide between the basins of the rivers Rhine and Danube. The Julier Pass lies between Piz Lagrev and Piz Julier. A few metres south of the summit is the small lake Lej da las Culuonnas.
Europe is traditionally defined as one of seven continents. Physiographically, it is the northwestern peninsula of the larger landmass known as Eurasia ; Asia occupies the centre and east of this continuous landmass. Europe's eastern frontier is usually delineated by the Ural Mountains in Russia, which is the largest country by land area in the continent. The southeast boundary with Asia is not universally defined, but the modern definition is generally the Ural River or, less commonly, the Emba River. The boundary continues to the Caspian Sea, the crest of the Caucasus Mountains, and on to the Black Sea. The Bosporus, the Sea of Marmara, and the Dardanelles conclude the Asian boundary. The Mediterranean Sea to the south separates Europe from Africa. The western boundary is the Atlantic Ocean. Iceland is usually included in Europe because it is over twice as close to mainland Europe as mainland North America. There is ongoing debate on where the geographical centre of Europe falls.
The Flüela Pass is a high mountain pass of the Swiss Alps in Graubünden. Traditionally considered the boundary between the Albula and Silvretta Alps, the pass crosses the watershed / drainage divide between the basins of the rivers Rhine and Danube. The pass is overlooked by the Flüela Schwarzhorn and the Flüela Wisshorn. The summit of the pass lies between the lakes Lai da la Scotta and Lai Nair.
A drainage divide, water divide, ridgeline, watershed, water parting or height of land is elevated terrain that separates neighboring drainage basins. On rugged land, the divide lies along topographical ridges, and may be in the form of a single range of hills or mountains, known as a dividing range. On flat terrain, especially where the ground is marshy, the divide may be difficult to discern.
The Alps form a large mountain range dominating Central Europe, including parts of Italy, France, Switzerland, Liechtenstein, Austria, Slovenia, Germany and Hungary.
Piz Kesch (German) or Piz d'Es-cha (Rumantsch) is a peak in the Albula Alps of the Rhaetian Alps in Switzerland. At 3,418 metres (11,214 ft), it is the highest peak in the Albula Alps and the municipality of Bergün, Grisons.
Piz Lunghin is a mountain in the Swiss canton of Graubünden, located in the Albula range, overlooking the Maloja Pass. It is considered as the "roof of Europe" as the peak is nearby the triple watershed of the Lunghin pass. Water running off this mountain can head towards the Mediterranean, the North Sea and the Black Sea, respectively by the rivers Po, Rhein, and Danube.
A continental divide is a drainage divide on a continent such that the drainage basin on one side of the divide feeds into one ocean or sea, and the basin on the other side either feeds into a different ocean or sea, or else is endorheic, not connected to the open sea. Every continent on earth except Antarctica has at least one continental drainage divide; islands, even small ones like Killiniq Island on the Labrador Sea in Canada, may also host part of a continental divide or have their own island-spanning divide. The endpoints of a continental divide may be coastlines of gulfs, seas or oceans, the boundary of an endorheic basin, or another continental divide. One case, the Great Basin Divide, is a closed loop around an endorheic basin. The endpoints where a continental divide meets the coast are not always definite since the exact border between adjacent bodies of water is usually not clearly defined. The International Hydrographic Organization's publication Limits of Oceans and Seas defines exact boundaries of oceans, but it is not universally recognized. Where a continental divide meets an endorheic basin, such as the Great Divide Basin of Wyoming, the continental divide splits and encircles the basin. Where two divides intersect, they form a triple divide, or a tripoint, a junction where three watersheds meet.
The Witenwasserenstock is a peak between the Swiss cantons of Valais and Uri, located in the Lepontine Alps. Close to the summit lies the tripoint border between the cantons of Valais, Uri and Ticino and the triple watershed of the Rhine, Po and Rhône basins.
The Danube is the second-longest river in Europe, after the Volga in Russia. It flows through Central and Southeastern Europe, from the Black Forest south into the Black Sea. A large and historically important river, it was once a frontier of the Roman Empire. In the 21st century, it connects ten European countries, running through their territories or marking a border. Originating in Germany, the Danube flows southeast for 2,850 km (1,770 mi), passing through or bordering Austria, Slovakia, Hungary, Croatia, Serbia, Romania, Bulgaria, Moldova, and Ukraine. Among the many cities on the river are four national capitals: Vienna, Bratislava, Budapest, and Belgrade. Its drainage basin amounts to 817,000 km² and extends into nine more countries.
Hydrology is the science which studies the water cycle as a whole, hence the water exchanges between soil and atmosphere but also between the soil and sub ground (groundwater).
A triple divide or triple watershed is a point on Earth's surface where three drainage basins meet. A triple divide results from the intersection of two drainage divides. Triple divides range from prominent mountain peaks to minor side peaks, down to simple slope changes on a ridge which are otherwise unremarkable. The elevation of a triple divide can be thousands of meters to barely above sea level. Triple divides are a common hydrographic feature of any terrain that has rivers, streams and/or lakes.
The Italian geographic region, Italian physical region or Italian region is a geographical region of Southern Europe delimited to the north by the mountain chains of the Alps. This subregion is composed of a peninsular and continental part and an insular part. Located between the Balkan Peninsula and the Iberian Peninsula, it protrudes into the centre of the Mediterranean Sea and overlooks the Adriatic Sea, the Ionian Sea, the Ligurian Sea, the Sardinian Channel, the Sea of Corsica, the Sea of Sardinia, the Strait of Sicily, and the Tyrrhenian Sea.
The Ebro Hydrographic Confederation is the organization that manages, regulates and maintains the water and irrigation of the Ebro hydrographic basin. The organization's headquarters are in Zaragoza and it was the first institution created in the world with the objective of managing an entire river basin in a unitary manner.