Debris flows are fast moving landslides of mixed water and poorly sorted debris (IVERSON, 1997; CRUDEN AND VARNES, 1996). Because of the high flow velocity, impact forces, and long runout, debris flows are commonly regarded as one of the most hazardous landslide types (JAKOB, 2005). The Dolomites region (NE Italian Alps) has one of the most frequent return intervals for large debris flows on the world (PASUTO AND SOLDATI, 2004; SKERMER AND VANDINE, 2005). In the Dolomites the landscape is dominated by steep dolomite massifs rising up to 3300 m a.s.l. The rocky cliffs are connected to the bottom of alpine valleys by means of milder slopes where bedrock is covered by a thick debris talus, deposited in post-glacial climatic conditions. Debris flow channels are deeply incised in the talus slope and feeded by small headwater basins located on the cliffs (MARCHI AND TECCA, 1992; BERTI et alii, 199). These basins are typically very steep (45°-60° on the average) and mostly consist of exposed bedrock with no vegetation and almost absent soil cover. During high intensity short duration thunderstorms, rainfall water is collected by the rocky watersheds as overland flow and trunk streams incised in bedrock, and quickly delivered to the talus cones. Most of this water infiltrates into the channel bed debris and flows downstream as subsurface stormflow. However, when the infiltration capacity of the streambed is exceeded, surface flow appears in the channel and debris flows are triggered by the progressive erosion of the loose bed debris (BERTI AND SIMONI, 2005). Although this initiation mechanism has been widely recognized in the field (e.g. CANNON et alii, 2003), monitoring data describing the onset of channel runoff and the triggering process are still lacking. In this paper we describe the monitoring systems installed on a typical debris flow catchment of the Dolomites (Dimai basin, Cortina d’Ampezzo, Belluno), with the main aim of describing the hydrologic response in the initiation area.
Berti M., Crucil G., Degetto M., De Vido G., Gregoretti C., Martina M., et al. (2012). Hydrologic response in the initiation area of the Dimai debris flow (Dolomites, Italian Alps). RENDICONTI ONLINE DELLA SOCIETÀ GEOLOGICA ITALIANA, 21, 564-566.
Hydrologic response in the initiation area of the Dimai debris flow (Dolomites, Italian Alps)
BERTI, MATTEO;SIMONI, ALESSANDRO
2012
Abstract
Debris flows are fast moving landslides of mixed water and poorly sorted debris (IVERSON, 1997; CRUDEN AND VARNES, 1996). Because of the high flow velocity, impact forces, and long runout, debris flows are commonly regarded as one of the most hazardous landslide types (JAKOB, 2005). The Dolomites region (NE Italian Alps) has one of the most frequent return intervals for large debris flows on the world (PASUTO AND SOLDATI, 2004; SKERMER AND VANDINE, 2005). In the Dolomites the landscape is dominated by steep dolomite massifs rising up to 3300 m a.s.l. The rocky cliffs are connected to the bottom of alpine valleys by means of milder slopes where bedrock is covered by a thick debris talus, deposited in post-glacial climatic conditions. Debris flow channels are deeply incised in the talus slope and feeded by small headwater basins located on the cliffs (MARCHI AND TECCA, 1992; BERTI et alii, 199). These basins are typically very steep (45°-60° on the average) and mostly consist of exposed bedrock with no vegetation and almost absent soil cover. During high intensity short duration thunderstorms, rainfall water is collected by the rocky watersheds as overland flow and trunk streams incised in bedrock, and quickly delivered to the talus cones. Most of this water infiltrates into the channel bed debris and flows downstream as subsurface stormflow. However, when the infiltration capacity of the streambed is exceeded, surface flow appears in the channel and debris flows are triggered by the progressive erosion of the loose bed debris (BERTI AND SIMONI, 2005). Although this initiation mechanism has been widely recognized in the field (e.g. CANNON et alii, 2003), monitoring data describing the onset of channel runoff and the triggering process are still lacking. In this paper we describe the monitoring systems installed on a typical debris flow catchment of the Dolomites (Dimai basin, Cortina d’Ampezzo, Belluno), with the main aim of describing the hydrologic response in the initiation area.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
