Orlegna

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Orlegna
The Orlegna at the end of the Val Forno

The Orlegna at the end of the Val Forno

Data
Water code CH : 5475
location Bernina Alps
River system Po
Drain over Mera  → Adda  → Po  → Adria
source on the Forno Glacier
46 ° 20 ′ 11 ″  N , 9 ° 42 ′ 3 ″  E
Source height approx.  2230  m above sea level M.
muzzle in the Mera near Löbbia Coordinates: 46 ° 22 ′ 57 "  N , 9 ° 39 ′ 35"  E ; CH1903:  770 847  /  139 205 46 ° 22 '57 "  N , 9 ° 39' 35"  O
Mouth height 1433  m above sea level M.
Height difference approx. 797 m
Bottom slope approx. 65 ‰
length 12.2 km
Catchment area 44.74 km²
Discharge  at the mouth of the
A Eo : 44.74 km² 		MQ
Mq
 		2.78 m³ / s
62.1 l / (s km²)
Left tributaries Riale Lägh da Cavloc
Right tributaries Val Muretto, Riale Margna
Communities Bregaglia

The Orlegna is a 12-kilometer left tributary of the Mera in the Swiss canton of Graubünden . It flows through the Val Forno in the Bernina Alps and runs entirely in the municipality of Bregaglia in the south of the canton.

geography

course

The Orlegna rises at about 2230  m above sea level. M. the Forno Glacier between Piz Casnil in the west and Monte del Forno in the east near the border with Italy . Initially it flows mainly to the north-northeast through the rearmost part of the Val Forno. After the water from the Laghetto dei Rossi flows in from the right, the Orlegna is dammed by a small dam at the Plancani water intake . This water passes through a pressure tunnel to Murtaira before it is fed through a pressure shaft into the power plant's power station in Löbbia.

Immediately after the dam, the stream from Val Muretto flows into Orlegna from the right . It now flows to the north-northwest and takes on the runoff of several small mountain lakes, including the Riale Margna . The Orlegna now forms a narrow gorge into which the Lägh da Cavloc drains from the left , before it reaches the dam of the Orden retention basin , which is supposed to protect the Bergell deep into Italy in the event of heavy rainfall. After this dam, it forms another gorge that stretches to Cavril . The serpentines of the Malojapassstrasse wind their way up the valley on the right bank .

In Cavril she turns to the southwest and passes Casaccia . Only a little later the Orlegna flows a little north of Löbbia at 1,433  m above sea level. M. from the left into the Mera. At the mouth, the Orlegna has a higher discharge and a larger catchment area than the Mera.

Catchment area

Orlegna near Orden near Maloja (1950)

The catchment area of ​​the Orlegna measures 44.74 square kilometers, of which 56.4% is unproductive area , 19.3% glaciers and firn, 14% wooded area , 8.1% agricultural area, 1% water area and 0.7% settlement area .

The highest point is at 3360  m above sea level. M. a little below the Cima di Castello on its eastern slope, the mean height is 2426  m above sea level. M. and the lowest point is at the mouth at 1433  m above sea level. M.

The mean discharge at the mouth is 2.78 m³ / s, with a maximum in July with 6.92 m³ / s and a minimum in March with 0.4 m³ / s.

Web links

Commons : Orlegna  - collection of images, videos and audio files

Individual evidence

  1. ↑ a b c Geoserver of the Swiss Federal Administration ( information )
  2. ↑ a b c Topographical catchment areas of Swiss waters: sub-catchment areas 2 km². Retrieved July 11, 2019 .
  3. ↑ Energy from hydropower. (PDF) In: ewz-Kraftwerke Bergell. Retrieved August 27, 2017 .