 |
| Titel |
A new debris-flow monitoring system in an Alpine catchment |
| VerfasserIn |
L. Marchi, F. Comiti, M. Arattano, M. Cavalli, P. Macconi, D. Penna |
| Konferenz |
EGU General Assembly 2012
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250063998
|
|
|
|
|
|
| Zusammenfassung |
| Monitoring of debris flows in instrumented catchments permits collection of data on these
phenomena and provides a valuable link with geomorphological and topographical
observations of erosion, sediment supply and channel-bed evolution. Numerous sites recently
instrumented in various geographical regions show that field monitoring is receiving
increasing attention in debris-flow research worldwide.
The poster presents a novel installation for debris-flow monitoring in the Gadria
catchment (Eastern Alps, Northern Italy). The Gadria basin has been chosen mainly because
of the relatively high frequency of debris flows (on average 1-2 per year). The Gadria
catchment has a drainage area of 6.3 km2 and ranges in elevation from 1394 m to 2945 m. An
important bedload tributary (Strimm, drainage area 8.5 km2, minimum elevation 1394
m, maximum elevation 3197 m) joins the Gadria channel close to a filter check
dam located near the alluvial fan apex, which has been set as the outlet of both
basins.
Sensors have been installed both in the Gadria and in the Strimm basins. The monitoring
equipment consists of rain gauges, radar sensors for flow depth, geophones for ground
vibrations, and videocameras with spotlights. Two radar sensors, four geophones and three
videocameras have been installed in the lower reach of the Gadria channel just upstream of
the previously mentioned filter check dam. A further monitoring station will be installed
approximately 500 m upstream along the main channel. Rain gauges and pressure transducers
for monitoring flow stage have been installed in the Strimm basin. Six water pore pressure
sensors, 28 spatially-distributed soil moisture probes (at 10 cm and 50 cm depth) and six
piezometric wells equipped with pressure transducers have been installed in the sediment
source areas in the upper portion of the Gadria catchment in order to describe and understand
the main hydrological controls connected to the debris-flow triggering and sediment
mobilization.
A small-magnitude debris flow, which occurred on August 5, 2011, has represented a first
test for the monitoring equipment. Debris-flow hydrograph, flow velocity and frames of
different phases of the debris flow recorded by the videocameras are illustrated in the poster. |
|
|
|
|
|
|