Mitigation planning based on the prediction of river blocking by a typical large-scale debris flow in the Wenchuan earthquake area

Liu, Jinfeng; You, Yong; Chen, Xiaoqing; Chen, Xingzhang

doi:10.1007/s10346-015-0615-0

Cited by 23 publications

(14 citation statements)

References 20 publications

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“…The debris flow transported a large mass of solid material into the Minjiang River, forming debris-flow alluvial fans, thereby blocking the river. Therefore, the flow area of the river decreased rapidly, causing the water level in the upper reaches to rise sharply and the velocity and erosion potential of the flood to increase (Liang et al, 2001;Yanites et al, 2006;Liu et al, 2016). As shown in Figure 8, farmland, houses, transportation routes, hydropower stations, and other important infrastructure in the upper reaches were completely submerged by flooding caused by the debris-flow alluvial fan blocking the Minjiang River.…”

Section: Dynamic Evolutionary Characteristicsmentioning

confidence: 99%

Formation-Evolutionary Mechanism Analysis and Impacts of Human Activities on the 20 August 2019 Clustered Debris Flows Event in Wenchuan County, Southwestern China

Liu

Gan

et al. 2021

Front. Earth Sci.

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Characterized by large scale, high frequency, and strong destructiveness, debris flow has become the most noticeable geohazards throughout the world, especially in the mountainous areas of southwestern China. On August 20, 2019, large-scale heavy rainfall pummeled Wenchuan County, Sichuan Province, Southwestern China, which resulted in a cluster of debris flows (the “8·20” clustered debris flows event), and caused considerable economic losses (approximately 3.4 billion RMB were lost) and heavy casualties (48,862 people were displaced, 16 people died and 22 people went missing). Based on field investigation, image data interpretation, mechanism analysis, and other methods, this study reveals the formation mechanism, dynamic evolutionary process, and impacts of human activities on the “8·20” clustered debris flows event. Results from a comprehensive analysis indicate that the occurrence of short-term, high-intensity rainfall and the excessive supply of solid material were the main factors that triggered this catastrophic event. With the debris flow flowing into the main river, this event presented an extremely apparent disaster chain effect. It is also found that improper site selection and inadequate design of human activities played a crucial role in the movement process of the debris flow that directly aggravated the losses. Finally, to improve debris flow prediction and prevention, some early warning and mitigation measures are discussed.

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Section: Dynamic Evolutionary Characteristicsmentioning

confidence: 99%

Formation-Evolutionary Mechanism Analysis and Impacts of Human Activities on the 20 August 2019 Clustered Debris Flows Event in Wenchuan County, Southwestern China

Liu

Gan

et al. 2021

Front. Earth Sci.

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“…The Kanako simulator is a kind of numerical simulation tool, equipped with an efficient graphical user interface (GUI), that can be used to reproduce flow and the piling up process of the debris flow in the area where a dam was set up (Liu et al, 2012(Liu et al, , 2015Nakatani et al, 2007. In this study, the Kanako simulator was used to analyse the effect of the check dams.…”

Section: Parameters Input For Numerical Simulationmentioning

confidence: 99%

“…The values are the same for all scenarios (no check dams, with check dams) in both catchments and are listed in Table 5. Some of the parameters (such as the mass density of bed material, mass density of the fluid phase, concentration of the movable bed, coefficient of erosion rate and coefficient of accumulation rate) are empirical values used in most debris flow cases (Liu et al, 2012(Liu et al, , 2015Satofuka and Mizuyama, 2005). Other parameters (such as channel elevation, channel width and mitigation works) were obtained from field investigation combined with topography measurements.…”

Section: Parameters Input For Numerical Simulationmentioning

confidence: 99%

“…1-4) were set for recording the simulation results of the change in debris flow peak discharge. The supplied hydrograph of the debris flow was generalised as a pentagon type (Liu et al, 2012(Liu et al, , 2015, and the duration was determined as 40 min based on the '8.8' debris flow event. Above all were the same conditions for numerical simulations of both catchments.…”

Section: Parameters Input For Numerical Simulationmentioning

confidence: 99%

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Effectiveness of debris flow mitigation strategies in mountainous regions

Xiong

Meng

Wang

et al. 2016

Progress in Physical Geography: Earth and Environment

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Debris flows represent major hazards in most mountainous regions of the world where they repeatedly result in disasters. In order to protect people and infrastructure against future debris flows, many debris flow catchments have been artificially intervened by employing various mitigation measures, including civil engineering works. However, the commonly adapted engineering measures, such as check dams, are not effective for every debris flow catchment, and the failure of such measures even causes more damage, e.g. the Sanyanyu debris flow catchment in Zhouqu, China, killed 1756 people. In order to research the effectiveness of engineering strategies and explore much more effective mitigation works for debris flows in the mountainous regions, we took the Bailong River catchment of Southern Gansu of China as study area, with special emphasis on Sanyanyu debris flow catchment (with civil engineering works) and Goulinping debris flow catchment (without civil engineering works), and comparatively analysed the two catchments. The comparative results show that both catchments have similar material source, geomorphological/environmental and climatic conditions, however, vegetation cover and rock hardness are poorer in Goulinping than in Sanyanyu, the catchment that underwent larger-scale debris flows, suggesting that the mitigation measures had been applied in Sanyanyu catchment were inappropriate. Subsequently, we simulated the effectiveness of controlling debris flow peak discharge with check dams at the lower part of Sanyanyu and Goulinping catchment using the Kanako simulator, and summarised argument based on the hypothesis and facts from positive and negative aspects. We draw the conclusion that it is not reasonable to build check dams in the two catchments and instead, drainage channels should be primarily considered for reducing debris flow hazards in such densely populated areas. Finally, we undertook detailed field investigations and experiments on the native plants in the region, and found that the ecological mitigation measure with planting Robinia Pseudoacacia on the debris flow deposits is an effective method to alleviate debris flow hazards. It is concluded that channel works combined with ecological measures are the preferable approaches to minimize the debris flow damage in debris flow catchments characterised with high mountains, concentrated rainfalls and active neotectonic movement.

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“…A typical effect of extreme rainfall events is the formation of multiple debris flow deposits along the main reach of the mountain stream [1][2][3], with a consequent increase in the hydraulic susceptibility of the surrounding areas [4,5]. The water impoundment that can form behind a debris flow deposit is a potential hazard for people and property.…”

Section: Introductionmentioning

confidence: 99%

Geometrical Characterization of Sediment Deposits at the Confluence of Mountain Streams

Stancanelli

Musumeci

2018

Water

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Debris flow injections from tributaries into a main mountain stream generate deposits of sediments which, in turn, result in obstruction and eventual damming of the river section. This contribution presents the results of a series of flume experiments on the dynamics of these deposits, with reference to three different types of blockage: no blockage, partial blockage, and full blockage. Results show that the shape of the deposit is mainly controlled by the ratio between the debris flow discharge and the main river discharge. The experimental dataset is used to develop a deposit resilience stability index based on the shape of the deposit contour retrieved from photos taken from above. The proposed index is based on the invariant elliptic Fourier coefficients and the dimensionless transverse obstruction parameter. The elliptic Fourier coefficients give information on the symmetry of the deposit contour. High symmetry indicates more stable and resilient deposits. The proposed index is calibrated on the basis of the flume experiments and tested with field data. The results are quite promising and suggest that the index can be appropriate for a fast hazard assessment of multiple debris flow deposits at a regional scale.

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Mitigation planning based on the prediction of river blocking by a typical large-scale debris flow in the Wenchuan earthquake area

Cited by 23 publications

References 20 publications

Formation-Evolutionary Mechanism Analysis and Impacts of Human Activities on the 20 August 2019 Clustered Debris Flows Event in Wenchuan County, Southwestern China

Formation-Evolutionary Mechanism Analysis and Impacts of Human Activities on the 20 August 2019 Clustered Debris Flows Event in Wenchuan County, Southwestern China

Effectiveness of debris flow mitigation strategies in mountainous regions

Geometrical Characterization of Sediment Deposits at the Confluence of Mountain Streams

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