Lac de Pérolles
Oldest gravity dam in Europe
The Perolles Lake (French Lac de Perolles ) is a Swiss reservoir in the canton of Fribourg at the foot of the city of Freiburg. The construction of the gravity dam of Perolles Lake was completed in 1872, making it the oldest concrete dam in Europe.
History
The engineer Guillaume knight had in his time an incredible vision: he wanted to jam with a wall the Sarine River to supply the city of Freiburg with drinking water and to generate tele dynamic energy with the artificial slope. Turbines should pump the water into the reservoirs of the city, from where hydrants and residential buildings were supplied with water. The pumps and drives for the tele dynamic cables are factory housed Skinny Au.
It should also be performed on the Perolles plateau via a tele cable dynamic motion energy to generate power for the sawmills there. The tele dynamic cable system is similar to a transfer belt which is guided on pillars over a large distance - similar to a modern cable car. Knight was convinced to bring this system to industrial progress to Freiburg.
Contrary to planning the reservoir supplied the sawmills until the spring of 1874 with energy that was very expensive. Still later - in the autumn of 1874 - the houses got their water, to desire the very quality left something.
In 1890 the electrification of the plant Lean Au began doing the tele dynamic system in 1895 was replaced by conventional generating electrical energy.
With the increase of the dam in 1910, the new power station was put into operation the Mount of Olives. A tunnel in the Sarine strap under the " Bürgeln hill " Perolles the lake was connected to the new plant Mount of Olives.
Today the lake is heavily filled with sediment, as in the more than 130 years, the Sarine river has deposited a lot of material at the dam. These deposits have partly led to the formation of small islands. In the picture with the view of the dam from the lake this island formation is visible in the form of a " green belt " consisting of shrubs.
Dam of lean Au
Sketch of the dam Skinny Au
The power station Mount of Olives
Technical data of the dam
The dam Maigrauge / Skinny Au was increased in 1910 by 2.5 meters, it measures 18 meters at the base and at the apex of 4.5 meters. From the storage volume of 0.4 million m³ of 0.3 million m³ are used effectively.
The tele dynamic system
The idea of Guillaume knight was extremely visionary for its time: The operation of a large sawmill and a carriage factory, which derive their operating power from a distance. With the turbines in the lean Au hydropower was performed by means of a cable down to the level of Perolles. These had to be overcome, a distance of about 1 km and a height difference of about 70 m. On pillars the cable was out and distributed through a small tunnel to the level of Perolles.
The city of Freiburg hoped for from the new industrialization of an upswing, which they desperately needed. The current and the electric motors made but the tele dynamic system very quickly obsolete.
Photo montage of a pillar with the cable tele dynamic system
The tunnel through the led the cable to the level of Perolles
Tunnel for the cable
The Perolles Lake as a nature reserve
The area of Perolles Lake is characterized by a rich flora and fauna. It was in 1961 declared a bird sanctuary. Since 1983, the area from the Creux -du -Loup to the dam nature reserve. On a 8 km long circular route information panels explain fauna, flora, geology, hydrology and history of the lake.