Debris-flow magnitude—frequency relationships for mountainous regions of Central and Northwest Europe

Geomorphology ◽  
1996 ◽  
Vol 15 (3-4) ◽  
pp. 259-273 ◽  
Author(s):  
Henk van Steijn
Keyword(s):  
Debris Flow ◽  
Mountainous Regions ◽  
Northwest Europe

Morphometrical analysis of Debris flow fans and torrential catchments in mountainous terrain in the northern Colombian Andes by machine learning techniques.

2021 ◽  
Author(s):  
Emanuel Castillo Cardona ◽  
Edier Aristizábal
Keyword(s):  
Machine Learning ◽  
Debris Flow ◽  
Land Use Planning ◽  
Machine Learning Techniques ◽  
Main Stream ◽  
Mountain Range ◽  
Mountainous Regions ◽  
Colombian Andes ◽  
Learning Techniques ◽  
Qualitative Variables

<p>Debris flow fans are commonly occupied by urban and rural settlements in mountainous regions such as in the northern Colombian Andes. Those fans are originated by violent surges of high sediment concentration that are then mobilized downstream by strong currents during torrential events highly destructive. Then, characterization and understanding of the dynamics that give rise to fans in tropical and mountainous regions such as Andean zone is a fundamental tool for land use planning. This research focuses on cartography of fans and catchments using digital elevation models in the central and western mountain range of the northern part of the Andean mountain belt. The methodology considered: morphometric measurements of the catchments and fans, lithological aspects of the catchments, type of catchments (torrential or no torrential). Then the correlation between morphometric parameters of fans and catchments is carried out, including relationships with qualitative variables by multivariate statistical analysis and machine learning techniques to find patterns between quantitative and qualitative variables. The results indicate that slope of the fans has a high correlation with Melton index of the catchments and with the slope of the main stream of the catchments. About the qualitative classification of the catchments in torrential and no torrential, it is observed that there are good discriminations for slope of the fan, volume of the deposits(fans), the relationship between the relief of the catchments and other variables. On the other hand, the lithology of the catchments does not have strong influences on the morphometry of the fans.</p>

scholarly journals Debris Flow Damage Assessment by Considering Debris Flow Direction and Direction Angle of Structure in South Korea

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 328 ◽  
Author(s):  
Dong Nam ◽  
Man-Il Kim ◽  
Dong Kang ◽  
Byung Kim
Keyword(s):  
South Korea ◽  
Debris Flow ◽  
Debris Flows ◽  
Impact Force ◽  
Mountainous Areas ◽  
Mountainous Regions ◽  
Impact Forces ◽  
The Impact

Recently, human and property damages have often occurred due to various reasons—such as landslides, debris flow, and other sediment-related disasters—which are also caused by regional torrential rain resulting from climate change and reckless development of mountainous areas. Debris flows mainly occur in mountainous areas near urban living communities and often cause direct damages. In general, debris flows containing soil, rock fragments, and driftwood temporarily travel down to lower parts along with a mountain torrent. However, debris flows are also often reported to stream down from the point where a slope failure or a landslide occurs in a mountain directly to its lower parts. The impact of those debris flows is one of the main factors that cause serious damage to structures. To mitigate such damage of debris flows, a quantitative assessment of the impact force is thus required. Moreover, technologies to evaluate disaster prevention facilities and structures at disaster-prone regions are needed. This study developed two models to quantitatively analyze the damages caused by debris flows on structures: Type-1 model for calculating the impact force, which reflected the flow characteristics of debris flows and the Type-2 model, which calculated the impact force based on the topographical characteristics of mountainous regions. Using RAMMS a debris flow runoff model, the impact forces assessed through Type-1 and Type-2 models were compared to check reliability. Using the assessed impact forces, the damage ratio of the structures was calculated and the amount of damage caused by debris flows on the structures was ultimately assessed. The results showed that the Type-1 model overestimated the impact force by 10% and the Type-2 model by 4% for Mt. Umyeon in Seoul, compared to the RAMMS model. In addition, the Type-1 model overestimated the impact force by 3% and Type-2 by 2% for Mt. Majeok in Chuncheon, South Korea.

scholarly journals Study on the combined threshold for gully-type debris flow early warning

2019 ◽  
Vol 19 (1) ◽  
pp. 41-51 ◽  
Author(s):  
Jian Huang ◽  
Theodoor Wouterus Johannes van Asch ◽  
Changming Wang ◽  
Qiao Li
Keyword(s):  
Debris Flow ◽  
Pore Pressure ◽  
Early Warning ◽  
Early Stage ◽  
Warning System ◽  
Early Warning Systems ◽  
Great Loss ◽  
Mountainous Regions ◽  
Pressure Threshold

Abstract. Gully-type debris flow induced by high-intensity and short-duration rainfall frequently causes great loss of properties and causalities in mountainous regions of southwest China. In order to reduce the risk by geohazards, early warning systems have been provided. A triggering index can be detected in an early stage by the monitoring of rainfall and the changes in physical properties of the deposited materials along debris flow channels. Based on the method of critical pore pressure for slope stability analysis, this study presents critical pore pressure threshold in combination with rainfall factors for gully-type debris flow early warning. The Wenjia gully, which contains an enormous amount of loose material, was selected as a case study to reveal the relationship between the rainfall and pore pressure by field monitoring data. A three-level early warning system (zero, attention, and warning) is adopted and the corresponding judgement conditions are defined in real time. Based on this threshold, there are several rainfall events in recent years have been validated in Wenjia gully, which prove that such a combined threshold may be a reliable approach for the early warning of gully-type debris flow to safeguard the population in the mountainous areas.

scholarly journals Catastrophic debris flow triggered by an extreme rainfall event in the Volcán village, January 2017. Cordillera Oriental of Argentina

2018 ◽  
Author(s):  
María Yanina Esper Angillieri ◽  
Laura Perucca ◽  
Nicolás Vargas
Keyword(s):  
Debris Flow ◽  
River Basin ◽  
Large Scale ◽  
Extreme Rainfall ◽  
Economic Losses ◽  
Low Grade ◽  
Extreme Rainfall Event ◽  
Conditioning Factors ◽  
Mountainous Regions ◽  
Slow Moving

Abstract. Slides, rockfalls, debris floods and debris flows are periodical events in the dry mountainous regions of Argentina, during times of torrential rainfalls. In the Grande River basin, Jujuy Province, these processes take place almost every summer. Extreme rainfall on January 10, 2017 caused the seasonal acceleration of large-scale and slow-moving landslides in the Los Filtros River basin. These slides broke down into a disaggregated mass, triggering a debris flow which transformed progressively downstream into a debris flood, producing widespread damage along a narrow valley (named Quebrada de Humahuaca), with the Volcán village withstanding the worst of the disaster. The event caused four fatalities and great economic losses, mainly destroying infrastructure and buildings. In order to document this catastrophic event and to explore its causes, a morphometric analysis of the Los Filtros river basin, tributary of the western margin of the Grande River and located on the Cordillera Oriental area, was carried out. The drainage network was derived from digital elevation models. In addition, some landslides were mapped using high-resolution satellite data acquired before and after the event. Of a total landslide area of 2.39 km2, 0.60 km2 was considered as active and 0.089 km2 as new sliding area (from 2015 to 2017) associated to the large-scale and slow-moving landslides. The geological characteristics of the study basin are very favourable conditioning factors in landslide generation. Precambrian-age low grade metaclastics shatter in the frost climate of the higher mountains and poorly consolidated Quaternary deposits along the sides of the gully erode readily and become source material for landslide that damage or bury roads, railroads, and houses. Finally, this study aims to increase knowledge of all the above-mentioned events in order to provide several methods of analysis for landslide prevention and control.

Rainfall Spatial variability, rainfall intensity–duration (ID) thresholds, and the initiation of debris flows in the eastern Italian Alps

2021 ◽  
Author(s):  
Oliver Francis ◽  
Hui Tang ◽  
Carlo Gregoretti ◽  
Matteo Berti ◽  
Martino Bernard ◽  
...  
Keyword(s):  
Debris Flow ◽  
Spatial Variability ◽  
Spatial Variation ◽  
Debris Flows ◽  
Rainfall Intensity ◽  
Shallow Water Equation ◽  
Italian Alps ◽  
Mountain Ranges ◽  
Mountainous Regions ◽  
The Impact

<p>Runoff-generated debris flows are a significant hazard in steep mountain ranges across the world. During intense rainfall storms, runoff can rapidly form in small steep basins and mobilise large volumes of sediment triggering debris flows which can damage infrastructure and endanger lives. A common method for forecasting debris flows is deriving empirical rainfall intensity–duration (ID) thresholds from previously recorded debris flow events in a given area. However, the storms which trigger debris flows usually are short and intense with high spatial variation making an accurate recording of the conditions responsible for initiation difficult.</p><p>In this study, we investigate the impact of the spatial variability of rainfall on debris flow initiation in small, steep, and debris flow prone catchments in the eastern Italian Alps (Dolomites) using the SWEHR (Shallow Water Equation Hairsine-Rose) numerical model. The modelled catchments are monitored by multiple rain gages which we use to quantify the uncertainty of the rainfall ID thresholds due to the spatial variation of rainfall by comparing empirical and numerically modelled thresholds. We also compare simulated triggering discharges for debris flows with available field observations in the study area. This study will help to improve the quality of hazard forecasting of debris flows in mountainous regions</p>

scholarly journals A preliminary study on the comprehensive threshold for debris-flow early warning

2016 ◽  
Author(s):  
Xiaoqiang Xue ◽  
Jian Huang
Keyword(s):  
Debris Flow ◽  
Pore Pressure ◽  
Early Warning ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Warning System ◽  
Great Loss ◽  
Mountainous Regions ◽  
Hazard And Risk ◽  
Preliminary Study

Abstract. Debris-flows not only cause a great loss of property, but also kill and injure people every rainy season in the mountainous regions of China. In order to reduce hazard and risk, several methods of assessing rainfall thresholds have been provided at present, based on statistical models. However, the limited rainfall data with debris-flow occurrence or non-occurrence makes threshold analyses very difficult. This paper, therefore, presented a kind of comprehensive threshold consisting of pore-water pressure from Terzaghi theory, and rainfall factors from frequent usage for predicting debris-flow occurrence. Rainfall and pore pressure data has been collected in a number of locations in Wenjiagou gully to assess critical rainfall and pore pressure values for debris flow initiation. The three-level early warning criteria (Zero, Attention, and Warning) has been adopted and the corresponding judgement conditions has been defined based on monitoring data in a real-time way. Finally, it is suggested that the combination of these two critical values might be a useful approach in a warning system for safeguarding of population in debris-flow prone areas.

Computational investigation of baffle configuration on impedance of channelized debris flow

2015 ◽  
Vol 52 (2) ◽  
pp. 182-197 ◽  
Author(s):  
C.E. Choi ◽  
C.W.W. Ng ◽  
R.P.H. Law ◽  
D. Song ◽  
J.S.H. Kwan ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Debris Flow ◽  
Interaction Mechanism ◽  
Back Analysis ◽  
Flume Experiments ◽  
Flow Energy ◽  
Mountainous Regions ◽  
Impact Forces ◽  
Flow Attenuation ◽  
Array Of Baffles

Channelized debris flows surge downslope in mountainous regions and have large impact forces. Arrays of debris flow baffles are frequently positioned in front of rigid barriers to engage torrents and attenuate flow energy. They are regularly designed on empirical and prescriptive basis because their interaction mechanism is not well understood. Numerical back-analysis of flume experiments using the discrete element method (DEM) is conducted to provide insight on flow interaction with an array of baffles. Varying configurations of baffle height, a second staggered row, and spacing between successive rows are examined. Upstream and downstream kinematics are monitored to capture and compare the Froude number, kinetic energy, and discharge resulting from each baffle configuration. Results from this study reveal that the height of baffles can be categorized relative to the initial approach flow depth (h), namely tall baffles (1.5h) and short baffles (0.75h). Tall baffles are characterized by the development of upstream subcritical flow conditions, whereas short baffles exhibit supercritical upstream conditions. Furthermore, tall baffles facilitate the suppression of overflow, and short baffles lead to excessive overflow that is supercritical in nature. Less flow attenuation occurs as the distance increases both upstream and downstream from each array of baffles. A second staggered row of short staggered baffles is ineffective in reducing debris kinetic energy, whereas tall baffles should be positioned as close as possible.

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