Lake Lei

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Lake Lei
Lago di Lei, in the background Pizzo Stella
Lago di Lei, in the background Pizzo Stella
Location: Region Lombardy (I)
Canton Graubünden (CH)
Tributaries: various mountain streams
Drain: Reno di Lei
Lake Lei (Lombardy)
Lake Lei
Coordinates 46 ° 28 '59 "  N , 9 ° 27' 18"  E Coordinates: 46 ° 28 '59 "  N , 9 ° 27' 18"  E
Data on the structure
Lock type: Arch dam
Construction time: 1961
Height of the barrier structure : 141 m
Height above the river bed : 133 m
Building volume: 850 000  m³
Crown length: 690 m
Operator: Kraftwerke Hinterrhein AG, Thusis
Data on the reservoir
Altitude (at congestion destination ) 1931  m slm
Water surface 4.12 km²
Reservoir length 7.7 km
Storage space 197 000 000  m³
Total storage space : 200 000 000  m³
Catchment area 46.5 km²
Design flood : 134 m³ / s
Map Lago di Lei.png
Detailed map

The Lago di Lei is an 8 km long reservoir , which (like the Lago di Livigno ) lies almost entirely in Italy , in the area of ​​the municipality of Piuro . Only the 141 m high dam and the 950 m long access tunnel are in Switzerland , in an exclave of the municipality of Ferrera above Alp Campsut.

The valley is called Valle di Lei and is traversed by the Reno di Lei (literally Lei-Rhein , formerly also Leibach ).

Technical specifications

The maximum water level is 1931 m above sea level. M. and the deep water level at 1830 m above sea level. M.

The systems belong to Kraftwerke Hinterrhein AG, which uses the stored water in Ferrera to drive a power station with an output of 185 MW. From there, the water flows into the Sufers reservoir .

Apart from the valley's own precipitation, the lake is fed with water from the neighboring Val Madris valleys and from the Averstal 9 km away with the help of mirror tunnels .


The water of Lago di Lei or Reno di Lei is the only water in Italy that flows over the Rhine into Lake Constance and further into the North Sea , similar to the water of Lago di Livigno , which also does not flow into the Mediterranean but into the Inn or the Danube and thus ultimately into the Black Sea .



From the north, the high valley of Val di Lei was very difficult to access before a tunnel was built on the Swiss side in 1957: the valley is closed off by a gorge below against Innerferrera , where the Reno di Lei flows into the Avers Rhine , so that the valley could only be reached on foot from the north via the steep and narrow detour through the Val digl Uors (lit. Bärental ).

On the other hand, the valley was used early on from Italy in the south via the Passo di Lei and the Passo di Angeloga for alpine pasturing.

Change between Italy and Switzerland

middle Ages

The valley was first mentioned as Val de Leylo in 1355. At that time, the valley was temporarily inhabited all year round by settlers from the south.

In 1462 the Counts of Werdenberg sold the valley of the Bergell municipality of Piuro (dt. Outdated Plurs ) in the course of their decline .

Three frets

Due to the Milan Wars , the entire Chiavenna Valley, including Piuro and the Val di Lei, fell to the Three Leagues in 1512 . Since the Three Leagues, for their part , had belonged to the Old Confederation since 1497 as an eternal co-ally or a related place , the Val di Lei belonged to Switzerland from 1512 to 1797.

During this time, namely in the 17th century, the valley was used not only for alpine farming, but also for ore mining.

Transfer to Italy

Since the establishment of the Cisalpine Republic and the associated demarcation in the Bergell in 1797, the Val di Lei and Piuro have officially belonged to Italy. The Congress of Vienna confirmed this loss of the federal common rule of Chiavenna to Italy, but even if Chiavenna and the main territory of Piuro were no longer marked as Swiss territory on Sheet XIX of the Dufour Map published in 1858 , the Val di Lei remained part of it Switzerland mapped. Only the Treaty of Convenzione tra l'Italia e la Svizzera per l'accertamento della frontiera fra la Lombardia ed il Cantone dei Grigioni of 1863 finally clarified the affiliation to Italy.


Building history

The construction of the Valle di Lei dam began in 1957. Engineer Claudio Marcello was responsible for planning the dam. Construction management was the responsibility of the Milan-based company Edison, today a shareholder in the Hinterrhein power plants . Up to 1500 people worked on the construction site. About ten workers were killed during the construction, their names are noted by a small chapel on Italian territory. First, two cable cars were built from Campodolcino over the Passo di Angeloga to transport material and workers. Then the access road with a tunnel was created. Two quarries were built especially for the construction of the wall.

The dam was completed in 1962. A border correction was then carried out: The area around the dam was ceded by Italy to the Swiss canton of Graubünden, while Alpe Motta, a little further north, was transferred to Italian territory. Today only ruins remain of the cable cars. Since the dismantling of the cable cars, there has only been a transport connection to the valley via Swiss territory.

When the reservoir was filled in 1963, 15 Alps were flooded together with the valley , for example Erebella , S. Anna (chapel of the valley), Palazzetto , Caurga , Mulacetto and Corbia di Sopra . What remains are the Alpe Mottala , Alpe Pian del Nido and Alpe Scalotta in the valley floor as well as the Alpe del Crot and the Alpe Motta north of the dam. The Alpe della Palù (formerly Alp la Palü ) was moved up from the lake bed to the left (western) end of the top of the wall.

Operating history

Lago di Lei shortly after the replenishment began in May 2013

For inspection purposes, the reservoir was completely emptied in autumn 2012. After the revision of the dam installations and the pressure shaft, refilling was initiated in spring 2013. It is expected to last until 2017. The fish occupation program is expected to last until 2018.

See also


  • Bündner Calendar 2010; Pp. 131-140
  • Storia per immagini della Val di Lei . Gregorio Luigi Fanetti. 2008.

Web links

Commons : Lago di Lei  - collection of images, videos and audio files

Individual evidence

  1. ^ Siegfried map ( Topographic Atlas of Switzerland )
  2. ^ Dufour map , topographic map of Switzerland .
  3. a b Jürg Simonett: Valle di Lei. In: Historical Lexicon of Switzerland . February 16, 2017 , accessed June 5, 2019 .
  4. ^ Dufour map from 1858, sheet XIX , accessed on June 8, 2013.
  5. ^ Publication date of sheet XIX Chiavenna-Bellinzona of the Dufour map.
  6. ^ State Treaty between Italy and Switzerland of 1863 , accessed on June 8, 2013.
  7. ^ Agreement between the Swiss Confederation and the Kingdom of Italy on the definition of the Italian-Swiss border on the route between Run Do or Cima Garibaldi and Mont Dolent , State Treaty, German version.
  8. Bündner Calendar 2010; P. 131.
  9. Agreement between the Swiss Confederation and the Italian Republic regarding a border adjustment in Val di Lei (PDF; 495 kB)
  10. Picture of the old cable car station , accessed on June 8, 2013.
  11. ^ Image of the installations of the old cable car station, accessed on June 8, 2013.
  12. Flooding of the Alps  ( page no longer available , search in web archivesInfo: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. the Val di Lei from 1963, contribution of Swiss television, accessed on June 9, 2013.@1@ 2Template: Dead Link /  
  13. Alp names on the Siegfried map ( online )
  14. Revision of the dam of Lago di Lei 2012/2013, contribution by Swiss television, accessed on June 9, 2013.
  15. ^ Article by Südostschweiz from October 24, 2012, accessed on June 9, 2013.