Protection against floods: the innovative
cable weir in the Rienza gorge

Relationship between man, mountain and technology

Every year, in Alpine regions like South Tyrol, numerous measures are taken to secure mountain streams. In recent times, experts are concentrating most on the issue of wooden debris. This is because just a few tree trunks are all it takes to block a bridge or cause an obstruction. This, in turn, can cause serious flooding.

Good Practice: The cable weir in the Rienza gorge

The Rienza springs at the feet of the Tre Cime of Lavaredo, in the Municipality of Dobbiaco. It then runs through Val Pusteria and into the Rienza gorge in Brunico. To the inhabitants of Brunico, the gorge is an important place for relaxation and an easily reached tourist destination. In addition to hikers, the gorge also attracts many water sports enthusiasts. For the territory of Brunico, one of the main problems is the wooden debris transported by the Rienza. Following obstructions, the city has often been subjected to large floods (the last dating back to 1998).
For this reason, a search was made for a solution that could be efficient and, at the same time, integrate in a non-invasive manner in the natural environment. A decision was therefore made to proceed with the first - and so far only - cable weir in the whole of South Tyrol. Construction work was carried out from April 2012 to June 2013.

The know-how behind the project
In South Tyrol, and throughout the Alpine region, there is little experience in terms of designing and building cable weirs. As a first step, the University of Padua and the FreeUniversity of Bolzano worked on a joint study on the issue of wooden debris in the territory of Brunico. Next, the Civil Protection Agency, the Ufficio Sistemazione Bacini Montani Est (Eastern mountain catchment basins management office) and the Ufficio Dighe (dam management office) created the criteria that had to be followed for construction in the area. The goal was to build a structure with the least possible impact on the landscape.
The technology
The cable weir is eight metres high and is made up of nine steel cables, each of which 50 metres long, across the Rienza river. The cables are fastened to the rocks on both sides using special tie-rods. The tie-rods are protected against corrosion, among other things, also thanks to expressly planned covers. The diameters of the cables vary between 31 and 95 millimetres.

The experts in our network:

  • Ingenieurteam Bergmeister
  • Kauer Ingenieure
  • Mair Wilfried
  • Niederstätter
  • Seik
  • Alpenbau
  • Klapfer Bau

The innoalptec project (FESR1060) is financed by the European Union and by the European regional development fund