Torrent control
Structural measures of river engineering are referred to as torrent or whitewater barriers , with which the dangers caused by torrents are to be eliminated or at least reduced and controlled. Several measures are combined.
history
Johann Georg von Aretin , then Bavarian road and hydraulic engineering inspector in Tyrol , dealt with the problem of torrents for the first time in 1808 ; he published his thoughts in the work on mountain falls and the means of preventing them or at least reducing their harmfulness. In 1826, Josef Duile followed, also in Tyrol, whose book About the construction of torrents in mountainous countries already contained specific technical and biological construction measures as well as detailed concepts for financing construction measures.
activities
Collecting funnel
In the collecting funnel (water catchment area) of the torrent, targeted reforestation has proven to be effective in order to stop erosion . The soil is fixed by the tree roots and the water can seep in better than on grassland.
Drainage channel
Corrective measures in the drainage channel aim to reduce the flow speed of the water with the help of structural measures. The transport capacity, but also the deep erosion, is contained by rubble barriers , stairs, base chords / sleepers and dams made of wood and / or concrete.
Alluvial fans
Corrections in alluvial fans primarily serve to quickly drain away water and debris . Where the space permits, bed load collectors are built at the beginning of the alluvial fan to separate the water from the bed load and hold back rubble and debris. The bed load collector must then be cleared out regularly. The water is drained through a channel that is as straight as possible.
Since alluvial fans (often at the same time the stream flows into a lake) are mostly populated today, building in the immediate danger zone must also be prevented with spatial planning measures.
Well-known torrent barriers
Germany
Austria
Switzerland
- Gürbe (destroyed in a flood in 1990 and subsequently rebuilt according to the latest knowledge)
- Küsnachter Dorfbach
- Gruonbach , Flüelen , Canton Uri
See also
literature
Norms:
- ONR 24800–3 protective structures for the torrent control