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Topic 6 - Debris-flow Monitoring and Alert Systems

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Topic 6 - Debris-flow Monitoring and Alert Systems
Since 2002, the Soil and Water Conservation Bureau, which is responsible for the conservation and administrative management of hillside in Taiwan, has been cooperating with Feng Chia University. Together, they have successively carried out the establishment and maintenance of 17 debris flow monitoring stations over the Taiwan and 3 mobile debris flow monitoring stations. Geophone is one of the most important sensor to detect whether debris flow occur or not. The wavelet transform is employed in this study t
Topic 6 - Debris-flow Monitoring and Alert Systems
Monitored observation stations represent a fundamental tool to properly investigate the initiation, flow behaviour and accumulation of debris flows. In the recent years, tree different monitoring stations have been built up in the Eastern Pyrenees. The instrumentation of all of them consists of four geophones and a rain gauge, while two of them also have an ultrasonic device and one site a video camera. First experiences regarding the set-up and calibration of the different devices indicate that debris-flow
Topic 6 - Debris-flow Monitoring and Alert Systems
Mass movements such as debris flows, rock fall and snow avalanches are sources of sub-audible sounds in the low frequency infrasonic and seismic spectrum. Recent studies indicated that debris flow-generated signals are of significant amplitude and occupy a relatively noise free band in the low frequency acoustic spectrum. Infrasound signals have the ability to propagate kilometres from the source, thereby allow monitoring of mass movements from a remote location. This study presents debris flow monitoring a
Topic 6 - Debris-flow Monitoring and Alert Systems
Sediment transport in steep mountain streams can occur as bedload or debris flows, depending on basin geomorphology and sediment supply conditions. This paper compares two small catchments located in the Eastern Italian Alps (Rio Cordon and Moscardo Torrent) where the dominant sediment transport processes differ substantially. The former hosts a measuring station for water and sediment transport rates operating since 1986, whereas the latter was set up in 1989 to monitor debris-flow events. Differences in s
Topic 6 - Debris-flow Monitoring and Alert Systems
To investigate rainfall-runoff conditions that generate post-wildfire debris flows, we instrumented and surveyed steep, small watersheds along the tectonically active front of the San Gabriel Mountains, California. Fortuitously, we recorded runoff-generated debris-flows triggered by one spatially restricted convective event with 28 mm of rainfall falling over 62 minutes. Our rain gages, nested hillslope overland- flow sensors and soil-moisture probes, as well as a time series of terrestrial laser scanning (
Topic 6 - Debris-flow Monitoring and Alert Systems
The article presents a debris-flow monitoring system installed in the site of Acquabona near Cortina d’Ampezzo, in the province of Belluno, Italy. The site, whose activity is almost annual, was equipped in the second half of the 90s, with the aim of characterizing the phase of initiation, flow and deposition of debris-flows typical of the Dolomitic areas. Three measuring stations were been realized. The power of the equipment was provided by solar panels. The field data were stored on site and recovered
Topic 6 - Debris-flow Monitoring and Alert Systems
Kamikamihorizawa Creek on the slopes of Mount Yakedake, Nagano Prefecture, was selected as a monitoring site for debris flows considering a high frequency of debris flow and instrumented with monitoring equipments in 1970: eight years after the last phreatic explosion of this volcano. The monitoring system was improved by adding speedometers, stage meters, seismometers and so on, in addition to the off-line monitoring surveys on the interaction between debris flows, hillslope hydrology and slope morphology.
Topic 6 - Debris-flow Monitoring and Alert Systems
Hydrophones are steel pipes containing a microphone, and they can be used to measure bedload transport intensity. Bedload discharge and average grain diameter can be calculated analytically using sound pressure data. In this study, hydrophones were used to identify debris flows. The proportional relationship between the output voltage corresponding to a grain collision and its momentum was used to analyze electric pressure distribution, which was then used to calculate the mean diameter of colliding grains.
Topic 6 - Debris-flow Monitoring and Alert Systems
In order to document the on-site debris flow events, the Soil and Water Conservation Bureau (SWCB), Council of Agriculture, Taiwan, has devoted to develop the debris flow monitoring system since 2002. This paper introduces the technology of 17 on-site and 3 mobile debris flow monitoring stations established by SWCB in Taiwan. In each on-site monitoring station, several observation instruments including rain gauges, CCD cameras, wire sensors, geophones, and water level meters were installed to collect the dy
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