The Verdon (river)
The the Verdon ( Verdoun in Occitan Provençal of Norme mistralienne) is a French Rivière which takes its source with the foot of the Head of Sestrière (altitude 2572 meters), between the Col of Ales and the Pic of the Three bishoprices (altitude 2819 meters), and is thrown in the Durance, close to the Vinon-on-Verdon, after having traversed approximately 175 kilometers.
The course of the Verdon is located essentially in the department of the Alp-of-High-Provence; however on several sections of its course it is used as border between this department and that of the Var; the very last kilometers are in the VAr, and the confluence with the Durance in the Rhone delta.
In its higher course, the Verdon with the pace of a torrent and presents an important slope: in the Saint-Andre-of-Alps, with 45 kilometers of its source, the river is already with 900 meters of altitude. Downstream from this point, gradually enlarged by its affluents, the Verdon crosses several mountainous links by imposing throats, of which several were equipped with hydroelectric stoppings. The Gorges of the Verdon are a tourist high-place. Its most interesting course, the “Large canyon”, is between Castellane and the Lac of Holy-Cross.
The green color of the Verdon is due to the Fluor and the microphone Algue S which it contains: it is probably at the origin of its name, formed starting from the Latin viridum , “place green”. However, in the lake of Holy-Cross or the reserve of Quinson, in particular, its water has a turquoise color due to the funds Argile ux.
HistoryThe Verdon, whose course is especially marked by the existence of narrow and major throats, generally played a part of border rather than of transportation route during the history, following the example Durance of which it is a Affluent. For this reason, today still the Rivière mark the limit enters the departments of the Alp-of-High-Provence and the Var. Lastly, it is notable that part of the Large canyon of the Verdon was explored only at the XXe century only.
Nevertheless, as many rivers the Verdon attracted the Man as of the Préhistoire: so traces of human occupation exist as of the Paléolithique on the low Verdon, it is especially the Neolithic which delivered in important quantities a material mainly preserved today at the Musée of the prehistory of the Gorges of the Verdon, with Quinson.
During the protohistoire, the high Verdon belongs to the alpine surface while the means and the low Verdon belong to Mediterranean space of Provence.
Some names of people of this period are known: the Gallitae or Gallites (literally “small Gallic”) with Ales (with the sources of the Verdon), are probably the Gallic ones of Cisalpine - Ombrien S -; the Suètre S populate the valley of the Verdon in Alp-of-High-Provence; the Reii , which gave their name to Riez, their “capital”, are as for them the most important Ethnie in the north of the low Verdon.
It is, indeed, especially on the course of the Colostre, affluent of the Verdon, and starting from the latter Oppidum which then seems to be itself developed an important human occupation: downstream from Laugh, the name of the village of Germany-in-Provence preserves the memory of a Gallic goddess and, not far from Saint-Martin-of-Bromines, the oppidum of Buffe-Arnaud dominates the strategic Confluent of Colostre and the Verdon. This last site was excavated at the time of the correction of the secondary road 952 in 1992 and in particular delivered a fragment of plastic bracelet laténien of style.
Riez remains an important city at the time Roman and Paléochrétienne: the ruins of a Roman temple and a octagonal Baptistère testify to the last splendor of this city which is then connected to Aix-en-Provence by the via sextiana .
With the Middle Ages, the noble families of Provence of Simiane, Pontevès and Sabran share the property of the villages of the Verdon with the bishop S of Laugh.
The Verdon is an extremely abundant river, like all the rivers resulting from the Alpine areas. Its flow was observed over one 37 years period (1969-2005), with the Vinon-on-Verdon, the level of its confluence with the Durance. The catchment area of the river is there of 1 820 km ², i.e. its totality.
Interannual medium flow or module of the river in the Vinon-on-Verdon east of 27,1 m ³ a second. For the figures which will follow, it is necessary to keep in mind which the profile of the river was modified by the series of storage dams built on its course.
The Verdon presents typical seasonal fluctuations of a hydrological mode to dominant nival. One indeed distinguishes two periods there from rising. The least important is that of high waters of autumn. The average monthly flow goes up then to 31,5 m ³ a second, in November. This period is followed of a light fall of flow up to 25,9 m ³ a second in December and 27,6 in February. A second rise of the mode follows then leading to a second top - most important - in April (39,1 m ³) and especially in May (48,2 m ³). It is due to the snow melt associated with the rains with spring. Consequently, as of June, starts fall followed of low waters of summer which is held July at September included and leads the medium flow to its plus-bas August with a monthly average of 10,4 m ³ a second, which remains very comfortable, it is true. On the whole, the seasonal oscillations appear thus not very important, since the average monthly flows are all in the fork ranging between 10 and 48 m ³, but the fluctuations much more marked are observed over moreover short periods, and also according to the years.
With the low water level, the VCN3 can fall until 0,060 m ³, in the event of dry period quinquennial, that is to say only 60 liters a second, which is extremely low. The VCN3 is the past minimal quantity or minimal flow over three days consecutive.
As for the risings, they are generally hardly important, and especially without common measurement with those of the Durance or the close Var. The river from now on is strongly regularized thanks to the series of stoppings with which it is equipped.
Thus the QJ 2 and QJ 5 or calculated daily outputs of biennial and quinquennial rising are worth respectively 110 and 160 m ³ a second. The QJ 10 or calculated daily output of decennial rising is of 200 m ³ a second, the QJ 20 of 230 m ³, while the QJ 50 is assembled to 280 m ³ a second (see note). Let us note that these flows of rising are more or less three times weaker than those of modest the Sèvre Nantes for example. That means however that, for example, every two years one must expect a rising of about 110 cubic meters, and that every five years, a rising of 160 cubic meters must statistically occur.
The recorded maximum daily output was of 668 m ³ a second on November 6th, 1994. By comparing this value on a QJ scale of the river, it appears that this rising was more twice the more important than the computed value for a rising cinquantennale, and thus highly improbable and certainly very exceptional.
On the whole, the Verdon is an abundant river, supplied with so abundant precipitations they which prevail in the area, and especially in the upper part of its basin. The Lame of water past in its catchment area is of 471 millimetres annually, which is high, largely higher than the overall average of France all confused basins, and also than the totality of the basin of the Durance. The specific Flow of the river (or Qsp) thus reached the figure of 14,9 liters a second and per square kilometer of basin.
Hydroelectric installationThe Verdon is described today as “Tower water” of the departments of the Rhone delta and the Var by Électricité de France: indeed, five stoppings were constuit on its course to feed out of water low Provence for the irrigation and the production of drinking water.
the high VerdonThe installation of the high Verdon is the first to take place: it is made gradually.
Between 1928 and 1932, the Hydroelectric Company of the Verdon (S.H.V.) is responsible for the building sites of Castillon and Chaudanne and profits for this task from the repairs which had by the Germany at the following day from the Great War. Following the bankruptcy of the company in 1932, work is stopped until 1938, date on which they begin again, initially temporarily under the crook of the Electrical energy of the Mediterranean coastline (E.E.L.M.), then definitively as from 1942.
Downstream, the dam Chaudanne, less important, is put out of water during the winter 1952 by Électricité de France (E.D.F.): located in a bolt of the solid mass of the Victoire, it is especially used to control the water flow.
the low VerdonOn the low Verdon, the phase of studies starts since 1926. The installation of the river is indissociable there of that of the Durance in which the Verdon completes its race.
In 1957, the Company of the Channel of Provence (S.C.P.) is created: as from 1963, a power station is built by E.D.F. in the Vinon-on-Verdon and a stopping is built with Gréoux-the-Baths. This stopping is thus used at the same time with the hydroelectric production, but also for the water supply of the Canal of Provence.
It gives rise to the reserve of Gréoux commonly called “lake of the Esparron-of-Verdon” and is completed in 1967.
Lastly, construction as from 1970 of the Stopping of Holy-Cross, in the throat of Baudinard: the reserve of the same name (the “Lake of Holy-Cross”) is put out of water in 1975 and covers a surface of 22 square kilometres to store 760 million cubic meters of water, of which 140 are reserved for agriculture.
Holy-cross forms the second plus artificial big lake of France (after that of Greenhouse-Ponçon) with 22 km ² and 760 million m ³ stored. Under its water are the source of Fountain-the Bishop (first source of France), many archeological sites (the results of the emergency excavations undertaken before the setting in water are visible with the Museum of the prehistory of the Gorges of the Verdon, with Quinson) and the village of the the Room-on-Verdon, rebuilt higher. 25 kilometers additional of road and two bridges had to be realized to ensure the circulation of reserve on both sides.
In 1975 also, a last stopping is completed in Quinson: it replaces preceding a 15 height meters work which had been built in 1868 to irrigate the plain of Aix-en-Provence and give rise to the reserve of Quinson, sometimes named “Lake Montpezat”. The main role of the latter is that of compensating reservoir of the stopping of Holy-Cross.
Principal affluents(of upstream downstream)
- the Issole (Right Bank, with the Saint-Andre-the-Alps)
- Jabron (left bank, with the clue of Carejuan)
- the Beam or Baou (Right Bank, with the entry of the Large canyon)
- the Artuby (left bank, in Mescla)
- the Colostre (Right Bank, little before Gréoux-the-Baths)
Principal sprinkled localities
- the Colmars-the-Alps
- the Saint-Andre-the-Alps
- the Vinon-on-Verdon
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