The bisses of Valais
The bisses, called Suonen or Wasserleitungen in Upper Valais, are channels that carry water from mountain streams and glaciers to the meadows, fields and vineyards of the dry slopes. Their history can be read in the village archives, which for centuries regulated the sharing of water.
How many bisses?
The number depends on how they are counted. The Association des Bisses du Valais cites three inventories: 265 bisses according to the Valais Bisses Museum, 580 according to Johannes Gerber, who also counts vanished ones, and 208 bisses totalling 785 km according to the canton's official inventory, completed in 2015, which leaves out most bisses shorter than 1'000 metres.
The first records
According to the Association, the oldest surviving documents date from the 13th century, and the sources become more detailed from the 15th century. In the territory of Chalais, a dense irrigation network developed from the 13th century.
The pages of this site give several dates. At Lax, a bisse was built in 1336 to bring water from the Deischbach, and the first water rights date from 1347. At Zeneggen, documents from 1343 and 1400 regulate irrigation by the Augstbord bisse. At Ried-Mörel, bisses and wooden flumes bringing water from the Massa gorge, at the Aletsch glacier, are recorded from 1385. The Association cites the Chänilwasser of Ausserberg (1420), the Torrent-Neuf of Savièse (1430) and the great bisse of Vex (1453).
Sharing the water
A bisse serves several families and sometimes several villages. Most of them belong to consortages, communities of owners who maintain the channel and share out the watering turns. Municipalities also set rules: at Varen, the municipality regulated the use of the Dala bisse in 1484, and again in 1493.
Sharing led to disputes. At Lax, the water of the Deischbach had to be shared with Martisberg, and an arbitration settled the division between the two municipalities in 1590.
Stone, wood and tunnels
The Association describes several techniques. Stone bisses are built using the Tretschbord method, with flat stones alternating with turf, in principle without mortar or concrete. Wood is also used: hollowed larch trunks, the «bazots», 45 to 60 cm in diameter, for flows below 50 litres per second, and flumes of assembled larch planks for larger flows.
In the 20th century, tunnels replaced many exposed sections. At Ried-Mörel, the water has run since 1946 through a 3 km tunnel under the Riederhorn. After an inventory drawn up in 1907 by Fritz Rauchenstein, the state subsidised modernisation work.
From neglect to hiking paths
With the spread of sprinkler irrigation, many bisses were partly or completely abandoned. At Savièse, the Torrent-Neuf is said to have been closed in 1934 and restored in 2005 (dates to be confirmed).
According to the Association, restorations multiplied from the 1980s, and many bisse paths became part of the cantonal hiking network. At Mase, the bisse path opened in 2002. At Salins, the Grand Bisse crosses the upper part of the municipality.
Unesco recognition in 2023
In December 2023 Unesco added traditional irrigation to the Representative List of the Intangible Cultural Heritage of Humanity. The nomination, coordinated by Austria, also included Germany, Belgium, Italy, Luxembourg, the Netherlands and Switzerland. For Valais, it names six consortages: those of the Sonnenberge of Upper Valais, Ayent, Lens, Trient, Nendaz and Grächen.
Places mentioned
- Ausserberg
- Savièse
- Vex
- Salins
- Chalais
- Grimisuat
- Lax
- Varen
- Zeneggen
- Ried-Mörel
- Grächen
- Birgisch
- Mund
- Eggerberg
- Mase
- Nendaz
- Ayent
- Lens
- Trient