scholarly journals Analysis of River Blocking Induced by a Debris Flow

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Lijuan Wang ◽  
Ming Chang ◽  
Xiangyang Dou ◽  
Guochao Ma ◽  
Chenyuan Yang
Keyword(s):  
Debris Flow ◽  
Return Period ◽  
Debris Flows ◽  
Small Volume ◽  
Disaster Prevention ◽  
Intense Rainfall ◽  
Residential Areas ◽  
The Wenchuan Earthquake ◽  
Movement Characteristics ◽  
Blocking Event

Both the Wenchuan earthquake on May 12, 2008, and the Lushan earthquake on April 12, 2013, produced many coseismic landslides along the Nanya River in Shimian City. Subsequent debris flows that initiated from these landslides and are triggered by intense rainfall become the secondary hazard in the years after the earthquake; in particular, some debris flows led to a serious river blocking event. For example, the Guangyuanbao debris flow which occurred on July 04, 2013, partly blocked the Nanya River, presenting a major threat to the national highway and residential areas. To analyze the pattern of landslide damming, we analyzed numerical simulations of the movement characteristics of the Guangyuanbao debris flow using rainfall intensities with varying recurrence periods of 5, 20, and 50 years. The accuracy of the spreading of the numerical simulation is about 90%. The simulation indicated a small volume of sediment entering the river for a rainfall under 5-year return period. A debris flow induced by rainfall under 20-year return period partly blocked the river, while rainfall under 50-year return period has potential to block the river completely. This proposed analysis of river blocking induced by a debris flow could be used for disaster prevention in earthquake-stricken area.

Modeling debris flow triggered by snow melting in the Barsemdara river valley, Tajikistan

2021 ◽  
Author(s):  
Viktoriia Kurovskaia ◽  
Sergey Chernomorets ◽  
Tatyana Vinogradova ◽  
Inna Krylenko
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Human Life ◽  
River Valley ◽  
Viscoplastic Fluid ◽  
Two Dimensional ◽  
Residential Areas ◽  
Subsequent Formation ◽  
Hazard Level ◽  
Output Information

<p>Debris flow is one of the most hazardous events that occur in all mountain regions.  Direct debris flow damage includes loss of human life, destruction of houses and facilities, damage to roads, rail lines and pipelines, vehicle accidents, and many other losses that are difficult to quantify. In July 2015, in the valley of the Barsemdara River (Gorno-Badakhshan Autonomous Region, Tajikistan), plenty of debris flows were observed. As a result, residential areas, social facilities, and infrastructure in Barsem village and neighboring settlements were destroyed and flooded. Besides, debris flow deposits blocked the Gunt River with the subsequent formation of a dammed lake with a maximum volume of 4.0 million m<sup>3</sup>. <br>The aim of this study was to obtain hydrographs of debris flow waves in the source and detailed zoning of the Barsemdara river valley. For the debris flow source, we applied transport-shift model. Equations of this model were developed by Yu.B. Vinogradov basing on Chemolgan experiments of artificial debris flows descending. Previously, the model characteristics were compared with the observational data of the Chemolgan experiments, and the results were found to be satisfactory [Vinogradova, Vinogradov, 2017]. Based on the equations, a computer program was created in the programming language Python. Besides, we improved the model by adding flow velocity calculations, and eventually it became possible to obtain hydrographs. To investigate quantitative characteristics of the debris flow in the river valley we implied a two-dimensional (2D) model called FLO-2D PRO. It is based on the numerical methods for solving the system of Saint-Venant equations. Besides, in this model, it is assumed that debris flows move like a Bingham fluid (viscoplastic fluid) [O'Brien et al., 1993]. The input information for modeling was digital elevation model (DEM) and previously obtained hydrographs. The output information included flow depth, velocity distribution and hazard level of the territory. The results of the study will be reported.</p><p>1.    Vinogradova T.A., Vinogradov A.Y. The Experimental Debris Flows in the Chemolgan River Basin // Natural Hazards. – 2017. – V. 88. – P. 189-198.<br>2.    O'Brien J. S., Julien P.Y., Fullerton W.T. Two-dimensional water flood and mudflow simulation //Journal of hydraulic engineering. – 1993. – V. 119, No 2. – P. 244-261.</p>

scholarly journals Characteristics of the Disastrous Debris Flow of Chediguan Gully in Yinxing Town, Sichuan Province, on August 20, 2019

2021 ◽  
Author(s):  
Li Ning ◽  
Tang Chuan ◽  
Zhang Xianzheng ◽  
Chang Ming ◽  
Shu Zhile ◽  
...  
Keyword(s):  
Debris Flow ◽  
Wenchuan Earthquake ◽  
Debris Flows ◽  
Warning System ◽  
Mitigation Measures ◽  
High Definition ◽  
Flood Peak ◽  
The Wenchuan Earthquake ◽  
Minjiang River ◽  
Monitoring And Early Warning

Abstract On August 20, 2019, at 2 a.m., a disastrous debris flow occurred in Chediguan gully in Yinxing town, China. The debris flow destroyed the drainage groove and the bridge at the exit of the gully. In addition, the debris flow temporarily blocked the Minjiang River during the flood peak, flooding the Taipingyi hydropower station 200 m upstream and leaving two plant workers missing. To further understand the activity of the debris flow after the Wenchuan earthquake, the characteristics of this debris flow event were studied. Eleven years after the Wenchuan earthquake, a disastrous debris flow still occurred in the Chediguan catchment, causing more severe losses than those of earlier debris flows. In this paper, the formation mechanism and dynamic characteristics of this debris flow event are analysed based on a drone survey, high-definition remote sensing interpretations and other means. The catastrophic debris flow event indicates that debris flows in the Wenchuan earthquake area are still active. A large amount of dredging work in the main gully could effectively reduce the debris flow risk in the gully. In addition, it is also important to repair or rebuild damaged mitigation measures and to establish a real-time monitoring and early warning system for the high-risk gully.

Quantitative analysis of the debris flow risk to concentrated rural settlement in southwest Sichuan, China

2021 ◽  
Author(s):  
Li Wei ◽  
Kaiheng Hu
Keyword(s):  
High Risk ◽  
Debris Flow ◽  
Debris Flows ◽  
Large Scale ◽  
Sichuan Province ◽  
Horizontal Distance ◽  
Rural Settlements ◽  
Residential Areas ◽  
Planning Stage ◽  
Societal Risk

<p><strong>Sichuan Province in southwest China is highly susceptible to debris flow disasters and suffers much damage to buildings and loss of human lives in concentrated rural settlements each year</strong><strong>.</strong><strong> By combining geographic information system (GIS) and Deep Encoding Network (DE-Net) methods, we proposed an automatic identification method for buildings highly susceptible to debris flows with large-scale digital elevation data and high-resolution remote sensing imagery based on a vulnerability matrix containing different threshold values of the horizontal distance (HD) and vertical distance (VD) between buildings and channels. A case study in Puge County, Sichuan Province, demonstrated the high identification potential of the method for buildings susceptible to debris flows in large areas with only scarce information available. Meanwhile, We chose </strong><strong>a high-risk village</strong><strong> in Puge County to study </strong><strong>debris flow risk to buildings and residents. Different</strong><strong> types of days and diurnal periods were considered in </strong><strong>the analysis of societal risk to residents</strong><strong>. The </strong><strong>results</strong><strong> indicated that societal risk to residents on holidays is always higher than that on weekdays, and societal risk at night is also much higher than that in the daytime. </strong><strong>The identification results of buildings vulnerability provide valuable information regarding high-risk residential areas to governments and facilitate targeted measure design at the initial planning stage, and the proposed method of societal risk provides a basis for decision-making in the planning of mitigation countermeasures in a specific settlement.</strong></p>

scholarly journals Characteristics of the disastrous debris flow of Chediguan gully in Yinxing town, Sichuan Province, on August 20, 2019

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ning Li ◽  
Chuan Tang ◽  
Xianzheng Zhang ◽  
Ming Chang ◽  
Zhile Shu ◽  
...  
Keyword(s):  
Debris Flow ◽  
Wenchuan Earthquake ◽  
Debris Flows ◽  
Warning System ◽  
Mitigation Measures ◽  
High Definition ◽  
Flood Peak ◽  
The Wenchuan Earthquake ◽  
Minjiang River ◽  
Monitoring And Early Warning

AbstractOn August 20, 2019, at 2 a.m., a disastrous debris flow occurred in Chediguan gully in Yinxing town, China. The debris flow destroyed the drainage groove and the bridge at the exit of the gully. In addition, the debris flow temporarily blocked the Minjiang River during the flood peak, flooding the Taipingyi hydropower station 200 m upstream and leaving two plant workers missing. To further understand the activity of the debris flow after the Wenchuan earthquake, the characteristics of this debris flow event were studied. Eleven years after the Wenchuan earthquake, a disastrous debris flow still occurred in the Chediguan catchment, causing more severe losses than those of earlier debris flows. In this paper, the formation mechanism and dynamic characteristics of this debris flow event are analysed based on a drone survey, high-definition remote sensing interpretations and other means. The catastrophic debris flow event indicates that debris flows in the Wenchuan earthquake area are still active. A large amount of dredging work in the main gully could effectively reduce the debris flow risk in the gully. In addition, it is also important to repair or rebuild damaged mitigation measures and to establish a real-time monitoring and early warning system for the high-risk gully.

scholarly journals Quantitative Analysis of the Effects of an Earthquake on Rainfall Thresholds for Triggering Debris-Flow Events

2021 ◽  
Vol 9 ◽  
Author(s):  
Shuang Liu ◽  
Kaiheng Hu ◽  
Qun Zhang ◽  
Shaojie Zhang ◽  
Xudong Hu ◽  
...  
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Rainfall Intensity ◽  
Focal Depth ◽  
Rainfall Threshold ◽  
Effective Rainfall ◽  
Rainfall Thresholds ◽  
Jiuzhaigou Earthquake ◽  
The Wenchuan Earthquake ◽  
The Moment

The impacts of destructive earthquakes on rainfall thresholds for triggering the debris flows have not yet been well investigated, due to lacks of data. In this study, we have collected the debris-flow records from the Wenchuan, Lushan, and Jiuzhaigou earthquake-affected areas in Sichuan Province, China. By using a meteorological dataset with 3 h and 0.1° resolutions, the dimensionless effective rainfall and rainfall intensity-duration relationships were calculated as the possible thresholds for triggering the debris flows. The pre- and post-seismic thresholds were compared to evaluate the impacts of the various intensities of earthquakes. Our results indicate that the post-quake thresholds are much smaller than the pre-seismic ones. The dimensionless effective rainfall shows the impacts of the Wenchuan, Lushan, and Jiuzhaigou earthquakes to be ca. 26, 27, and 16%, respectively. The Wenchuan earthquake has the most significant effect on lowering the rainfall intensity-duration curve. Rainfall threshold changes related to the moment magnitude and focal depth are discussed as well. Generally, this work may lead to an improved post-quake debris-flow warning strategy especially in sparsely instrumented regions.

Risk Assessment and Control Measure of Debris Flow in Chunyashu Gully of Seismic Disastrous Area of Sichuan Province

2012 ◽  
Vol 446-449 ◽  
pp. 2988-2991
Author(s):  
Ji Hua Chen ◽  
Hui Ge Wu ◽  
Hai Hui Zhou ◽  
Hai Liang Zhang
Keyword(s):  
Risk Assessment ◽  
Debris Flow ◽  
Wenchuan Earthquake ◽  
Debris Flows ◽  
Loose Material ◽  
Control Measure ◽  
Assessment Method ◽  
Sichuan Province ◽  
The Wenchuan Earthquake ◽  
And Control

The terrain of Chunyashu gully in Dujiangyan city of Sichuan province was steep, plenty of loose material increased after the Wenchuan earthquake. Debris flows were triggered in September 2008 and August 2009, and the debris flow was a serious threat to the highway and the residents. Risk of Chunyashu gully debris flow had been analyzed by the latest assessment method, and the result was that the risk degree of this gully was middle. Finally according to the local situation the control measure of interception dam and other advices had been suggested to protect the safety of the residents.

Key Problems on Debris Flow Control Engineering after Wenchuan Earthquake in China

2020 ◽  
Author(s):  
Yanchao Gao ◽  
Songjiang Zhao ◽  
Jiazhu Wang ◽  
Wei Xu
Keyword(s):  
Debris Flow ◽  
Wenchuan Earthquake ◽  
Debris Flows ◽  
Large Scale ◽  
Control Measures ◽  
Western China ◽  
Design Parameters ◽  
Disaster Prevention ◽  
Check Dam ◽  
Control Engineering

<p>Strong earthquakes often induce a substantial rise in secondary geohazards. This problem has been studied more after the Great Kanto Earthquake in Japan and the Chichi Earthquake in Taiwan. In western China, after the 2008 M<sub>w</sub>7.9 Wenchuan earthquake, large-scale regional debris flows occurred in 2008, 2009, 2010, 2011, 2013, 2014, and 2019 in the strong earthquake zone. Many control projects have been constructed, including more than 1,000 check dams. Part of the projects were damaged in the subsequent large debris flows. Debris flow after the earthquake is characterized by many loose sources, high frequency and large magnitude. Traditional design parameters and control engineering cannot meet disaster prevention requirements. In the 11 years after the Wenchuan earthquake, our research team continued to investigate the formation of the debris flow in the earthquake area, and summarized the reasons for the failure of the control projects, such as the low estimate of the loose sources and the insufficient design capacity of the check dam. In response to the above problems, we have proposed corresponding solutions, including the optimal combination of different control measures, the design of the dam site and storage capacity, and the structural form of the check dam. This optimization concept has been applied in debris flow prevention such as Qipan gully and Shaofang gully and has achieved good control results. The research provides a reference for subsequent disaster prevention and mitigation in similar earthquake areas.</p>

Catastrophic debris flows triggered by the 20 August 2019 rainfall, a decade since the Wenchuan earthquake, China

Landslides ◽  
2021 ◽  
Author(s):  
Fan Yang ◽  
Xuanmei Fan ◽  
Srikrishnan Siva Subramanian ◽  
Xiangyang Dou ◽  
Junlin Xiong ◽  
...  
Keyword(s):  
Wenchuan Earthquake ◽  
Debris Flows ◽  
The Wenchuan Earthquake

scholarly journals Learning Case Study of a Shallow-Water Model to Assess an Early-Warning System for Fast Alpine Muddy-Debris-Flow

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 750
Author(s):  
Antonio Pasculli ◽  
Jacopo Cinosi ◽  
Laura Turconi ◽  
Nicola Sciarra
Keyword(s):  
Debris Flow ◽  
Shallow Water ◽  
Early Warning ◽  
Debris Flows ◽  
Early Warning System ◽  
Warning System ◽  
Extreme Weather Events ◽  
Water Model ◽  
Computational Time ◽  
Processing Unit

The current climate change could lead to an intensification of extreme weather events, such as sudden floods and fast flowing debris flows. Accordingly, the availability of an early-warning device system, based on hydrological data and on both accurate and very fast running mathematical-numerical models, would be not only desirable, but also necessary in areas of particular hazard. To this purpose, the 2D Riemann–Godunov shallow-water approach, solved in parallel on a Graphical-Processing-Unit (GPU) (able to drastically reduce calculation time) and implemented with the RiverFlow2D code (version 2017), was selected as a possible tool to be applied within the Alpine contexts. Moreover, it was also necessary to identify a prototype of an actual rainfall monitoring network and an actual debris-flow event, beside the acquisition of an accurate numerical description of the topography. The Marderello’s basin (Alps, Turin, Italy), described by a 5 × 5 m Digital Terrain Model (DTM), equipped with five rain-gauges and one hydrometer and the muddy debris flow event that was monitored on 22 July 2016, were identified as a typical test case, well representative of mountain contexts and the phenomena under study. Several parametric analyses, also including selected infiltration modelling, were carried out in order to individuate the best numerical values fitting the measured data. Different rheological options, such as Coulomb-Turbulent-Yield and others, were tested. Moreover, some useful general suggestions, regarding the improvement of the adopted mathematical modelling, were acquired. The rapidity of the computational time due to the application of the GPU and the comparison between experimental data and numerical results, regarding both the arrival time and the height of the debris wave, clearly show that the selected approaches and methodology can be considered suitable and accurate tools to be included in an early-warning system, based at least on simple acoustic and/or light alarms that can allow rapid evacuation, for fast flowing debris flows.

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