Lake Aiguebelette

The Lake Aiguebelette , which means” beautiful small water”, is a natural lake of the Savoyard Avant-Pays, in the the French Alps.

Located at approximately 10 kilometers of Chambéry (Savoy) as the crow flies, the Lake Aiguebelette, with a surface of: 545 hectares, is the fifth French natural lake, after the Lac Léman, the Lac of Hourtin and Yokes, the Lac of Le Bourget and the Lac of Annecy. Bordered in the east by the Chaîne of the Spine which culminates with the Mount Hails with: 1425 meters and in the west by the Mount Tournier, its maximum depth is of 71 meters. With the first glance, it is characterized by its often green color, whereas the Annecy Lake is more blue and the lake of Le Bourget more often gray steel.

The banks of the lake are divided between five bordering communes: Aiguebelette, Lépin-the-Lake, Saint-Alban-with-Montbel, Novalaise and Nances. In the southern part of the lake two islands surrounded by Roselière S. are.

Geography

On the chart opposite, one distinguishes the three pits well from the lake:

  • the northern pit, close to the locality " Combe" (50 meters);
  • the south-eastern pit (71 meters), not far from the Port of Aiguebelette;
  • the south-western pit, between the islands and Lépin.

Volume of water: 166 million cubic meters.

The lake has cold completion at the time of the winters 1909, 1929, 1941, 1942 and 1956.

Geological formation

According to Michel Tissut, the mechanism of formation of the Lake Aiguebelette is very comparable with that of the lake of Le Bourget:
  1. With the secondary era (Jurassic and Cretaceous inferior), of the enormous masses of sediments settles in seamen circle.
  2. With the tertiary era, the reliefs starts to leave the sea. In the pit of Novalaise, not very deep Lagoon, the Molasse settles, crumpling brings the mountain of the Spine and the chain of the Mount Tournier (anticlines) at their current altitude.
  3. With the quaternary era, the glacier würmien surcreuse a basin with the foot of the great fault of the anticline of the chain of the Spine. At that time, the ice reaches an altitude of more than thousand meters, thus planing the reliefs and working the collars of Lépine and the Crucifix.
  4. With the cast iron of the ices, the lake fills. The moraine, in north, the molassic hills in the south, the anticlines, in the east and the west, delimit the basin. Water will run out by the point low, which is a zone of Faille in the anticline of the Tournier Mount.

History of the men

Piles inserted in not very major zones, on the commune of Lépin, vestiges of dwellings on Piloti S, or “palafittes”, attest of a human presence as of the time of the Neolithic and the Bronze Age. It is in the middle of the 19th century that archeologists discovered the existence of these quoted lake.

Thereafter, the area of the Lake Aiguebelette was sometimes a west-east crossing point, sometimes a country in margin. A Roman way passed by southern bank of the Lake before climbing the coast of the collar Saint-Michel and going down again on Chambéry which was called then Lemencum . This route, direct, but escarpé, was competed with by other ways in north (collar of the Cat) and in the south (Scales), undoubtedly more attended if one believes of it the poverty of the Roman archaeological vestiges found in Lépin compared with those which one finds towards Saint-Pierre-of-Genebroz and who correspond to the road of the Scales.

According to Andre Charvet, the route of the collar Saint-Michel remained by far more attended to join Chambéry until the end of the 17th century. At the beginning of the 17th century, for a quarter of ecu, carriers help the travellers to cross the coll the lord of Villamont, which borrows the passage in 1588 estimates that it is sufficiently well kept to protect the traveller “from the bears and other wild beasts” which one finds in wood. Starting from 1665, under the reign of Charles-Emmanuel II, duke of Savoy, great work were initiated to arrange the road Scales which had the great advantage of borrowing the collar of Couz, 300 meters lower than the collar Saint-Michel. From now on Aiguebelette will not be any more one crossing point.

Before 1860 indeed, the Lake Aiguebelette is not in France, but in Savoy, with some fifteen kilometers of the border with France, delimited by Guiers. At the 18th century, the smugglers are numerous, and most known is Mandrin. One can imagine that a certain number of the companions of Chuck were originating in banks of the lake, but this is not attested.

With the Middle Ages, according to Yvonne Coudurier, the mountain of the Spine belongs to the stronghold of the lords of Montbel who dominated the major part of the Savoyard Avant-Pays, whereas Lépin, Aiguebelette and the lake belonged to the stronghold of the lords of Aiguebelle who had their castle at the village of Aiguebelette. The name of Aiguebelette would come thus from Aiguebelle.

Although starting from the end of the 17th century, the whole of the west-east traffic was diverted on the way of the Scales, the direct way by southern banks of the lake forever be abandoned and the old Roman way become “Sardinian Way” remained maintained. During two centuries, the communes of the south of the lake, Lépin and Aiguebelette thus know only one relative insulation which is broken in 1884 by the opening of the railway line Lyon-Chambéry. A tunnel of: 3310 meters had been bored between Aiguebelette and Saint-Cassin-the-cascades. Whereas before, the circumferences of the lake were a strictly agricultural area, the arrival of the railroad supports the development of a small tourist activity: the hotel-pension-restaurants multiply. The Lyoneses form a large part of the customers. One sees also appearing a certain number of second home. After the Second world war, the tourist activities are dominated by the camp-site and the caravanning and of many camps is installed around the lake, with Netherlander customers faithful from July to August.

In the Years 1960, the trunk road RN  6 is blocked at the peak periods by terrible stoppers with the tunnel of the Scales. To solve the problem, in 1974, one opens with circulation the highway A43 which very connects Lyon to Chambéry while passing close to northern bank of the lake before being inserted in a new tunnel dug under the mountain of the Spine. This highway allows an easier access to the lake, but it generates a series of threats for the ecological balance of the lake: discharge of salts of thawing of ice and residues of tires.

By putting the bordering communes of the lake at less than 15 kilometers of the agglomeration chambérienne, the highway transforms this one into zone périurbaine. At the beginning of the 21e century, the population of the communes which had known a constant decrease corresponding to the Rural migration sets out again with the growth. It is a phenomenon of Rurbanisation which results in the construction of many principal residences in the bordering communes.

Fauna and flora

Poisson

The presence of various fish species in the lake results at the same time from natural balances and the activity predatory of the fishermen and from that, compensation, of the angling club which reconstitutes each year the reserves of Alevin S (Alevinage). The most current fish of the lake are the white fish (Ablette, Gardon (fish), Rotengle, Bremen, Carpe, Tanche), the Perches, the Brochet S, the Lotte S and the Salmonidé S (Omble, Truite and Lavaret).

Dice the arrival of the cold, the Ablette S of the lake probably gather in benches which move towards the Gua or the outfall or the port of Aiguebelette, because water is less cold there and less rare food. Not only the bleaks must ensure their survival, but they must be kept of their two large predatory, the Brochet S and the fishermen. Fortunately for the safeguarding of the species, their capacity of reproduction can be very strong under favorable conditions, but it is nevertheless the stocking with fish which ensures the strong representation of the species in the lake.

Whereas the pike drives out out of not very deep water, near the roselières, the Truite, which feeds especially from night competes with pike little because it drives out out of deeper water. In the lake, one finds Rainbow trouts]], recently introduced and trouts of lake, living discreetly out of deep water, with the shelter of the lines of the fishermen.

The poles, very required by the fishermen, are at the same time in competition with the lavarets, the burbots and pikes.

The Omble knight was introduced into the lake only in the years 1970. Their reproduction which must take place with more than fifty meters of depth is possible in the large pits of the lake.

The Lavaret, only saw him in-depth, out of sufficiently oxygenated water, except at the time of the spawning time or it goes up on the surface. Enough abundant in the lake, it represents a catch of choice for the experienced fishermen of the Lake Aiguebelette.

The Burbot, much rarer, is practically not fished with the line. It is a basic fish whose some specimens only are caught with the basic line.

Birds

  • the Foulque macroule is abundant on banks of the lake, except during the winter;
  • the crested Grèbe, is the most visible bird of the lake;
  • the Canard mallard was formerly the bird more represented on the lake, but it becomes rare.

Plants of the wetland

Ecological problems

The study of a lake concerns a discipline that one calls the Limnologie, founded at the end of the XIXeme century by François-Alphonse Forel.

Stratification and oxygenisation of water of the lake

, Aiguebelette Lake is laminated in December the April, in two layers, the épilimnion, ten, surfacing meters of depth, and representing approximately one the third of the total volume of the lake, and the Hypolimnion which is in lower part. These two layers carry out few exchanges between them.

In spring and in summer, the épilimnion whose temperature rises under the action of solar light becomes the seat of an activity of the Phytoplancton, microscopic plants which use solar light to make Photosynthèse and to thus give a green color to certain zones of the lake. Studies showed the presence of 93 species different of phytoplankton. In addition to the phytoplankton, the épilimnion is also inhabited by Zooplancton, animals microscopic, and fish. The whole of these living beings consumes oxygen. At the beautiful season, there is more oxygen generated by photosynthesis than of oxygen consumed by the living beings.

The hypolimnion which does not receive light remains all the year at a very low temperature (5à 6 degrees). During the beautiful season, the zooplancton which lives there consumes oxygen as well as the organic sediments which oxidize. Certain particular fish species like the Corégone S and the ombles knights also live in the hypolimnion.

So that the hypolimnion is not impoverished completely oxygenates some, it is thus necessary that water of the two layers mixes. For the Lake Aiguebelette, this occurs normally in winter when the temperature of the épilimnion goes down sufficiently low so that both to reach that of the hypolimnion. At equal temperature, water of the two layers can mix. The mixture is also supported by the storms and the risings of the brooks which are thrown in the lake, the emissary.

It is considered that the lake is in good health, or Oligotrophe when the two layers are well oxygenated and that consequently the various plant species and animal can live there as well surfaces some as out of deep water. If not, one speaks about a process of Eutrophisation. Y-a it risks eutrophication for the Lake Aiguebelette?

Risk eutrophication

1. Phosphates

Since the years 1970, a rather strict regulation imposed the installation of sewers all around the lake. Of this fact the pollution of human origin was considerably reduced, and agriculture is the major source of phosphate discharge in water of the lake. The Phosphate S support the production of vegetable organizations: A little phosphate is necessary for the production of phytoplankton and, therefore, of the oxygenisation of water, but too many phosphates make possible the production of such a quantity of phytoplankton and algae which the transparency of water is deteriorated by it and which the light is stopped on the surface. Moreover, part of the algae and plankton which develop are toxic.

So that a lake does not become eutrophic, one admits, according to Michel Tissut, a limit of 0.01mg/l for the content of water phosphates. In the Lake Aiguebelette, this content was into 1974-76 of 0.02 mg/l. It was gone down again to 0.01 mg/l in 1984. As comparison, in the Lake of Le Bourget, the content was assembled to 0.4 mg/l in 1978. Phosphate pollution was thus less important than elsewhere in the Lake Aiguebelette. Nevertheless, it is located nevertheless near to the threshold of eutrophication.

2. Salts of thawing of ice

Since 1974, date of opening of the highway A43, the content of the lake chlorides passes from 3-5 mg/l to 8-9 mg/l. In first approach, it is not necessary to consider that such a concentration could have detrimental effects on the potability of water or ecological balances, but one observed, in 1984, the starter of the formation of a " under-couche" located, whose chloride concentration reached the 10 mg/l. According to Michel Tissut, the durable establishment of an underlayer denser than the average of the lake could limit the mixing of water to the roadbase and would have fatal consequences for the oxygenisation of the bottom.

Threats on the roselières

Most of banks of the lake is occupied by Roselière S. the two islands, in particular, are completely surrounded by these roselières. The reeds are propagated by budding of the rhizomes. The base of the stems is immersed at a shallow depth. The tangle of the rhizomes and the roots constitutes the natural habitat of crayfish. The pikes come to clear there. The reeds have a purifying role, this is why their destruction is prohibited. Nevertheless, the development of the camp-sites and the search for new accesses to the lake involve each year the destruction of new roselières.

Tourist activities and sporting

Many fishermen, occasional or more regular devote themselves to their favorite occupation - as amateurs only, because the trade of fish of the lake is prohibited.

The calm the reigning the majority of time, lake, unsuitable dish with the practice of the sports of veil, is equipped with a base of oar, created in 1981, in the place of the old villa of the writer Frederic Dard/San-Antonio, where come to involve high level teams. The lake was selected for the championships of the world of Aviron of 1997. An order of the prefect of 1976 interdict the use of motor boats on the lake.

The chain of the Spine, on northern bank of the lake, was equipped with a Via ferrata known as Of the head of horse , prohibited access since 2005 for safety reasons. The parapente is very present, with a takeoff of the peak of the Spine, the parapentists being able to come to be posed close to the lake.

Literature

The Lake Aiguebelette inspired some writers:

  • Henry Bordeaux, writer of Savoyard origin, elected to the French Academy in 1919, spent the holidays to Aiguebelette and located at it the framework of the one of its novels, the white Peacock .

  • Frederic Dard, originating in Bourgouin, which had a villa at the edge of the lake, locates part of the action of Tango Chink (1965), signed San-Antonio.

Sources of the article

  • Michel Tissut, For the love of a lake , published by the FAPLA, 1987
  • Andre Charvet, countries of Guiers , 1984
  • Yvonne Coudurier, the Lake Aiguebelette , 1986

See too

External bonds

  • geological Page of Geol-Alp on the area of the Lake Aiguebelette
  • Tourist office of the lake
  • Federations of Associations of Protection of the Lake Aiguebelette (FAPLA)

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