the mass transport of stones, gravel, mud (“bedload”), and wood (“woody debris”).įloods develop as a result of extreme precipitation, which, in torrent catchment areas, leads to rapid increase in run-off and consequently to floods in the valley.

the debris cone in the lower reaches, the zone of bedload deposition, which is often densely populated.Īmong the most important hazards in torrential catchment areas are.

the middle reaches, the area of bedload transport, and.

the upper catchment (upper reaches), the precipitation collection area,.

All catchment areas of a Federal Province are listed in an ordinance of the competent Provincial Governor.Ī torrent can be roughly divided into three sections: There are about 12,000 torrent catchment areas in Austria. The catchment area of a torrent comprises the area of precipitation that the torrent and its inlets drain as well as the area where the torrent deposits its material. There they occur on steep hillsides and typically do not overcome great differences in height but often have larger catchment areas than mountain streams have.

Less often, torrents exist in hilly flatlands. The main characteristics of torrents in the Alpine area are their high gradients and the differing run-offs which, due to snow-melting or heavy thunderstorms, vary strongly within short periods of time. In the Austrian Forest Act 1975 torrents are defined as follows: “A torrent is a permanently or temporarily flowing waterway which, as a consequence of its rapid, only short-term swelling, removes solid material from its catchment area or its bed to a dangerous extent, carries this along and deposits it within or outside its bed or carries it to another stretch of water.” (Forest Act 1975, section 99 para.1)

Ministry of rock 2 torrent