Река Дюранс: Истоки и течение в Альпах и Провансе.

the commune in the Lot et Garonne department
River in France
Its source is in the southwestern part of the Alps, in the Montgenèvre ski resort near Briançon; it flows southwest through the following departments and cities:
Hautes Alpes: Briançon, Embrun. Alpes de Haute Provence: Sisteron, Manosque. Vaucluse: Cavaillon, Avignon. Bouches du Rhône. The Durance's largest tributary is the Verdon. Similar names are found in the names of many rivers in the Western Alps: Dora in Italy, Dranse in Haute Savoie, and the Drôme in south eastern France. All these rivers have their sources in mountains, and are fast running. The Durance retains its name rather than either the Clarée or Guisane, even though the latter two are longer than the Durance when they each merge. The Durance is better known than the other two rivers because the Durance valley is an old and important trade route, whereas the valleys of the Clarée and Guisane are effectively dead ends.

The Durance is long from its source at the foot of Sommet des Anges, at high, above Montgenèvre, to its confluence with the Rhône. However, a longer route is traced by the Clarée Durance system with a length of Its descent is unusually rapid at 81 m/km (165 ft/mi) in its first , then 15 m/km (30 ft/mi) to its confluence with the fr, and then still nearly 8 m/km (16 ft/mi) to the confluence with the Ubaye. This descent stays relatively steep after this confluence, then shallows to approximately 0.33% in its middle course (to the Mirabeau bridge), then 0.24% in its lower course. For comparison, at approximately from its source, the Isère is at altitude and the Durance at , which contributes partially to its fast flowing nature, including in the lower part of the river. It drops from its source to Mirabeau and approximately from its source to the confluence with the Rhône.

The source of La Durance is on the northern slope of the fr, where the first small streams combine into a river. This runs near to Montgenèvre and then flows into the larger Clarée river, and then passes through Briançon before the Guisane joins it. It then continues south combining with the Gyronde  — the Écrins glacial stream — at L'Argentière la Bessée. The confluence with the Guil occurs below Guillestre and Mont Dauphin. The Durance then flows south south west and flows into the Lac de Serre Ponçon just downstream of Embrun. The confluence with the Ubaye was flooded as the lake filled.

The middle part of the Durance runs through a landscape that changes as the valley increasingly widens. The river itself becomes steeply banked by terraces, and carves a channel, sometimes a few metres deep, sometimes tens of metres deep. In its middle and lower reaches the Durance is affected by the Mediterranean climate: flooding after autumnal rains, with low water levels in summer. Just before the narrow gap in the mountains at Sisteron, the Durance joins Buëch and the Sasse. Water also flows in from the EDF Canal. Beyond Sisteron further rivers and streams join the Durance: Jabron, Vançon, Bléone near Les Mées and from the Asse (river) a few kilometres to the south of Oraison. The Verdon flows into the Durance near Cadarache. The valley widens still further into an alluvial plain several kilometres wide ( near Manosque). Here the river was diverted for the development of modern agriculture and the construction of the A51 motorway. There are several dams along the middle part of the Durance. In addition to main dam at Serre Ponçon, there are dams at Espinasses, Sisteron, L'Escale and Cadarache. There are small canals whose primary purpose is to draw water from the river into the EDF Canal which in turn feeds the hydroelectric power stations. Some of the water diverted by the dams is used for irrigation.

The valley narrows for a few kilometres until the water gap at Mirabeau, at a depth of , then widens again into an even broader plain until the confluence with the Rhône south of Avignon. Its direction changes from southerly to westerly then northwesterly, aligning with the small Provençal mountain ranges between which it flows (Alpilles and Luberon). The Durance receives only one significant tributary on this last part of its course: the Calavon, which flows around the Lubéron range to the north.

This is a list of rivers longer than that flow into the Durance. At the confluence with Ubaye, salmon used to thrive, and trout were found up as far as Sisteron, before the development of the river. Later it becomes a Mediterranean river with the characteristic morphology.

The sources of the water are a combination of melting snow and the drainage of rain from the surrounding hills and plateaux which have a Mediterranean climate. The latter's tributaries bring rain water mainly in spring, autumn and winter but little during the summer. At Serre Ponçon, its basin of can create a flow as low as and a maximum flood of (value recorded in 1957). levels reached in 1843, 1882 and 1886. At the outlet into the Lac de Serre Ponçon, the medium flow is ;). The contribution of water from the downstream tributaries is very low. The annual maximum flow generally occurs in May or June, but the most violent flash floods occur in autumn. The lowest water levels occur in winter in the upper valley, and in summer in the middle and lower part of the river.

The river is famous historically for its unstable course and violent floods. In the 12th century the Durance had swept away the town of Rama (between Briançon and Embrun, with the confluence of Biaisse)
These increased in number and force from the second half of the 16th century, though lessened in the 20th century. The period of increased flooding was not only due to the cooling starting from the 14th and until the 19th century (with increased rain and snowfall), but also because the major deforestation of the slopes of the mountains of the basin of the Durance, starting from the 16th century. Between 1832 and 1890, the Durance had 188 floods of more than (measured at the Mirabeau Bridge). The flood of 1843 carried away several newly built suspension bridges: the 1829 bridge at Remollon, the 1835 bridge at Mirabeau, the unfinished bridge at Manosque and the 1838 bridge at Les Mées. The flood of 1872 also swept away the 1847 bridge at Mallemort. The catastrophic floods of 1843, 1856, 1886 attained For comparison, the Seine flooding of 1910 was estimated at approximately Even lesser floods were devastating. The flood of 31 May and 1 June 1877 swept away the bridge of Tallard. In the 20th century, the floods were less frequent and violent thanks to the dams and the re afforestation in the Durance basin, but there were still serious floods in 1957 and 1994 with maxima measured at Mirabeau and at Sisteron of ; and this volume was increased at the confluence with the Verdon by a further .

Dams have been built since the Middle Ages to prevent flooding. At first they were often boxes of wood filled up of stones, but these do not resist the floods for long. Dams have also long been used for irrigation. The first known irrigation canal is the fr, dug in 1171 by the Marquis de Forbin. It was followed by the Adam de Craponne canal, long, dug in nine months in 1554 from fr to Arles), the canal des Alpilles, the canal de Marseille, the fr, the fr, the canal de Ventavon, and the hundreds of other smaller ones, totalling dug between the end of the 16th century and the end of the 19th century.

From 1839 to 1854, the engineer Franz Mayor de Montricher built a canal to supply the city of Marseille with drinking water. It is long with underground. The canal is made out of concrete, and the aqueducts out of stone or stone and brick. The volume of water flowing through the canal is with the slope of The width across the surface of the canal is , and at its base. The water was first abstracted near the bridge of Pertuis, at an elevation of , from Marseilles. From there the canal diverges to the west from the Durance to Le Puy Sainte Réparade. Following the construction of the large EDF canal, which follows the Durance from Serre Ponçon until Salon de Provence and the Étang de Berre, the water for the canal of Marseilles is now taken from the EDF canal, below Saint Estève Janson. From there to Marseille the canal follows an path, of which is underground. The Durance provides today two thirds of the water for the city of Marseilles.

The Durance used to have an average natural flow of and behaved like a Mediterranean river, but dams and canals have changed it considerably. When the flow is low, most of the water in the river now flows in "industrial channels" which by pass the natural course of the river to run through hydro electric power stations. These channels can take up to , so that it is only at the time of high flows that the water not diverted uses the river's natural channel.

Along the river there are many habitats of both regional and European importance that are naturally governed by the varying flow of the river. These habitats include both mountain and Mediterranean types. The river with its valley is an important biological corridor, within the national green infrastructure and the Pan European ecological network. Consequently, it is classified as a Natura 2000 protected area. Currently there are between 150 and 200 species of benthic macroinvertebrates, but with few plant species (due to the greatly changing flow of the river). Water quality is considered good in the higher valley, in spite of the number of dams, which deprive the Durance of the power needed to carry sediment away. This quality was obtained thanks to actions of clean up projects on the river itself and on the tributaries of the Luye and Calavon (also called le Coulon)). There remain some black spots in the valley (downstream from the Arkema factory at Château Arnoux, below the confluence with the Calavon. The depth variation results in significant temperature variations, from seasonally; daily temperatures have 7.5 °C (46 °F) of amplitude in the summer and 10 °C (50 °F) in the winter. These are a significant factor in the biodiversity of the river. The dams in the valley have reduced the incidence of floods and so have allowed the colonisation of alluvial space by alder and poplar in riparian forests. The banks, although less wet, still accommodate 110 species of birds during the year, plus 82 species of migratory birds, which rest, feed and sometime reproduce. One hundred ten species of animal hibernate there. The populations of algae and water plants (100 species on average) and water invertebrates (77 species) are more varied than before the dams compared with populations on the similar Asse and Buëch. Ludwigia, the primrose willow, is an invasive plant having gradually spread since 1986 in the stagnant water in dead gravel pits and ponds. There are only fourteen fish species, including some native species: souffia, south west European nase and large populations of Zingel asper and spined loach which are both endangered species of fish. But the silting and the lack of oxygen has greatly reduced the number of trout. The European brook lamprey has been seen in recent times but it may have disappeared since.

The Durance played a very important part in the history of Provence, and largely contributed to the economic growth and population of the Marseilles area, after having been an obstacle for centuries. From Antiquity until the 19th century, the Durance was famous for the difficulty of crossing it, its massive floods and an inconstant flow. The width of its bed, the force and depth of its current, and the changes of course after the floods hindered crossing by ford. The only durable fords are those of Mirabeau and Pertuis, obviously unusable in periods of floods. The changes in the flow also limited river navigation (in spite of size of the river in periods with a high flow. It sometimes needed several ferries to cross the various arms or channels. The unstable and sometimes steep banks prevented easy access to ferries. In more recent times even suspension bridges often had to be re built after floods.

In 1843, 1856, 1882 and 1886 there were catastrophic floods. The 1852 floods affected the entire basin of the Durance, from Sisteron to its confluence in Avignon. It washed away many cultivated alluvial terraces, broke dams and destroyed canals. The irrigation syndicates and the local services that maintained the roads and bridges requested exceptional help from the State. A service to monitor the river was created, the Service spécial de la Durance, in order to study the hydrology of the river, using the kilometre long divisions from 1868 between the confluence with the Verdon with that with the Rhône. This division allows surveying and mapping of the land at risk. The construction of the Marseille canal in the middle of the 19th century allowed the metropolitan area of Marseille to develop quickly.

The is a series of multi product replenishment oilers, originally designed and built for service in the French Navy.