Lac de l'Abbaye
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The Lac de l' Abbaye is a lake in the French Jura, in the Jura, 8 km west of Morez and about 40 kilometers north- west of Geneva. It is situated in 879 m above sea level. M. on the ground community of Grande -Rivière and occupies an area of approximately 0.9 square kilometers. Located on a peninsula on the northeastern shore is the Abbey of Grandvaux.
Geography
The lake is 2.1 km long, up to 600 m wide and extends in a southwest-northeast direction according to the general strike of the Jura range in this section of the Central Mountains. It lies on the edge of the wide valley of the Grandvaux in the high Jura. In the southeast of Lac de l' Abbaye is flanked by the wooded ridge of the Forêt de la Joux Devant. The other riverside areas are flat and in some cases show a swamp belt on ( bog Les Touvières in the north). The greatest depth of the lake is 19.5 m. The Lac de l' Abbaye is fed by two short streams and probably several sources below the water surface. Because of the low flows the water has a relatively long mean residence time from an estimated two years. The drainage of the Lac de l' Abbaye is happening underground. The water seeps into the area below the hamlet Sur le Moulin. Labeling experiments have shown that the water in the karst spring Source de l' Enragé in an air distance of 21 km in the south-southwest at Molinges outcrops in the valley of Bienne only again. The Seezirkulation performed according to the dimictic type. In many winters of Lac de l' Abbaye freezes completely because of his high position in a basin (formation of a cold air lake ).
Geology
In structural geological terms, the Lac de l' Abbaye is located in a synclinorium of the Jura Mountains. The Syncline Grandvaux forms a broad depression between the ridge of the Forêt de la Joux Devant in the southeast and Forêt de la Joux Derriere in the northwest. The pending in the basin marly rock layers date from the Upper Cretaceous. During high stages of the various ice ages, the pool was lined by the Jura glaciers with marl and clay, which abdichteten the otherwise permeable subsoil so far that could arise in the valleys Moore and lakes.