Debris Flow Hazards and its Mitigation Works in Xianbuleng Gully, Jinchuan County, Sichuan Province, China

2012 ◽  
Vol 166-169 ◽  
pp. 2769-2773
Author(s):  
Jin Feng Liu ◽  
Yong You ◽  
Xing Chang Chen
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Case Analysis ◽  
Sichuan Province ◽  
Alluvial Fan ◽  
Drainage Canal ◽  
Hydraulic Condition ◽  
Township Government

This paper presented a case analysis of debris flow hazards and its mitigation works. The Xianbuleng Gully which is located in Jinchuan County, Sichuan Province was selected as study area. This gully is an old debris flow gully which once burst out many debris flow disasters in history. If debris flows occur again in this gully, the township government, the center school and 13 village houses nearly 300 persons on the alluvial fan will be exposed to great risk.The environment settings and the hazard characteristics of the Xianbuleng debris flow were introduced first in this paper. Then, mitigation works especially the drainage canal under the optimal hydraulic condition were planned and designed in the gully for decreasing the debris flow hazards.

scholarly journals Debris-flow activity in abandoned channels of the Manival torrent reconstructed with LiDAR and tree-ring data

2011 ◽  
Vol 11 (5) ◽  
pp. 1247-1257 ◽  
Author(s):  
J. Lopez Saez ◽  
C. Corona ◽  
M. Stoffel ◽  
A. Gotteland ◽  
F. Berger ◽  
...  
Keyword(s):  
Debris Flow ◽  
Tree Ring ◽  
Debris Flows ◽  
Temporal Distribution ◽  
Alluvial Fan ◽  
Tree Ring Data ◽  
Pine Trees ◽  
Spatio Temporal ◽  
Flow Activity ◽  
Abandoned Channels

Abstract. Hydrogeomorphic processes are a major threat in many parts of the Alps, where they periodically damage infrastructure, disrupt transportation corridors or even cause loss of life. Nonetheless, past torrential activity and the analysis of areas affected during particular events remain often imprecise. It was therefore the purpose of this study to reconstruct spatio-temporal patterns of past debris-flow activity in abandoned channels on the forested cone of the Manival torrent (Massif de la Chartreuse, French Prealps). A Light Detecting and Ranging (LiDAR) generated Digital Elevation Model (DEM) was used to identify five abandoned channels and related depositional forms (lobes, lateral levees) in the proximal alluvial fan of the torrent. A total of 156 Scots pine trees (Pinus sylvestris L.) with clear signs of debris flow events was analyzed and growth disturbances (GD) assessed, such as callus tissue, the onset of compression wood or abrupt growth suppression. In total, 375 GD were identified in the tree-ring samples, pointing to 13 debris-flow events for the period 1931–2008. While debris flows appear to be very common at Manival, they have only rarely propagated outside the main channel over the past 80 years. Furthermore, analysis of the spatial distribution of disturbed trees contributed to the identification of four patterns of debris-flow routing and led to the determination of three preferential breakout locations. Finally, the results of this study demonstrate that the temporal distribution of debris flows did not exhibit significant variations since the beginning of the 20th century.

scholarly journals Quantitative Analysis of the Debris Flow Societal Risk to People Inside Buildings at Different Times: A Case Study of Luomo Village, Sichuan, Southwest China

2021 ◽  
Vol 8 ◽  
Author(s):  
Li Wei ◽  
Kaiheng Hu ◽  
Jin Liu
Keyword(s):  
Quantitative Analysis ◽  
Debris Flow ◽  
Debris Flows ◽  
Evaluation Model ◽  
Alluvial Fan ◽  
Economic Losses ◽  
Rural Settlements ◽  
Societal Risk ◽  
Flow Intensity ◽  
The Village

Debris flows, which cause massive economic losses and tragic losses of life every year, represent serious threats to settlements in mountainous areas. Most deaths caused by debris flows in China occur in buildings, and the death toll is strongly dependent on the time people spend indoors. However, the role of time spent indoors in the quantitative analysis of debris flow risk has been studied only scarcely. We chose Luomo village in Sichuan atop a debris flow alluvial fan to study the influence of the temporal variation in the presence of people inside buildings on the societal risk. Two types of days (holidays vs. workdays) and two diurnal periods (daytime vs. nighttime) were considered in our risk evaluation model. A questionnaire survey was conducted for each family in the village, and the probability of the temporal impact of a debris flow on every household was calculated based on the average amount of time each member spent in the house. The debris flow hazard was simulated with FLO-2D to obtain the debris flow intensity and run-out map with return periods of 2, 10, 50, and 100 years. The risk to buildings and societal risk to residents were calculated quantitatively based on the probabilities of debris flow occurrence, the probability of the spatial impact, and the vulnerabilities of buildings and people. The results indicated that societal risk on holidays is always higher than that on weekdays, and societal risk at night is also much higher than that in the daytime, suggesting that the risk to life on holidays and at night is an important consideration. The proposed method permits us to obtain estimates of the probable economic losses and societal risk to people by debris flows in rural settlements and provides a basis for decision-making in the planning of mitigation countermeasures.

scholarly journals Sedimentology, dynamics and debris flow potential of Champadevi River, southwest Kathmandu, Nepal

1970 ◽  
Vol 10 ◽  
pp. 9-20
Author(s):  
Naresh Kazi Tamrakar ◽  
Achut Prajapati ◽  
Suman Manandhar
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Alluvial Fan ◽  
Shear Stresses ◽  
Stream Power ◽  
Huge Amount ◽  
Sedimentary Characteristics ◽  
Unconsolidated Material ◽  
Flow Potential ◽  
Headward Erosion

Mountainous and hilly regions are potential for debris flows, one of the major forms of natural disasters, which cause serious damage in downstream areas. The southwestern region of the Kathmandu Valley experienced catastrophic flows in the Champadevi River and its two tributaries (the Aitabare and the Raute Rivers) in July 2002. These rivers were investigated for morphologic, hydraulic and sedimentary characteristics to evaluate potential of debris flow in the area. The Raute and the Aitabare Rivers have tendency of headward erosion due to abrupt drop of gradient down the scarp of the alluvial fan deposit composed of unconsolidated matrix-supported gravel and mud. Because of this tendency, the rivers erode their substrate and banks, and contribute slope movements by sheding a huge amount of clasts and matrix. Therefore, instability condition of rivers and unconsolidated material available in the river courses potentially contribute for debris flow. The tractive shear stresses in the Aitabare, the Raute and the Champadevi Rivers (1.27, 1.60 and 0.48 KPa, respectively) exceeds twice the critical shear stresses required to transport 90th-percentile fraction of the riverbed material (0.14, 0.18 and 0.11 KPa). The stream powers (10.8, 17.2 and 5.1 m-kN/s/m2) of these rivers also greatly exceed the critical stream powers (0.21, 0.35 and 0.18 m-kN/s/m2) required to initiate traction transport. Because the tractive shear stresses and the stream powers that are achieved during bankfull flow are several times larger than the corresponding critical values, even the flow having stream power exceeding the critical stream power may potentially generate debris flow.   doi: 10.3126/bdg.v10i0.1416 Bulletin of the Department of Geology, Tribhuvan University, Kathmandu, Nepal, Vol. 10, 2007, pp. 9-20

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 Human-planted alder trees as a protection against debris flows (a dendrochronological study from the Moxi Basin, Southwestern China)

2013 ◽  
Vol 40 (3) ◽  
pp. 208-216 ◽  
Author(s):  
Ireneusz Malik ◽  
Yongbo Tie ◽  
Piotr Owczarek ◽  
Małgorzata Wistuba ◽  
Wojciech Pilorz ◽  
...  
Keyword(s):  
Adverse Effects ◽  
Debris Flow ◽  
Environmental Stress ◽  
Debris Flows ◽  
Monsoon Season ◽  
Sichuan Province ◽  
Southwestern China ◽  
Annual Rings ◽  
Flat Surfaces ◽  
Alnus Nepalensis

Abstract Large debris flows have destroyed the infrastructure and caused the death of people living in the Moxi Basin (Sichuan Province, Southwestern China). Inhabitants of the Moxi Basin live on the flat surfaces of debris-flow fans, which are also attractive for farming. During the monsoon season debris flows are being formed above the fans. Debris flows can destroy the houses of any people living within the fan surfaces. In order to prevent the adverse effects of flows, people plant alder trees (Alnus nepalensis) at the mouths of debris flow gullies running above debris flow fans. Alders are able to capture the debris transported during flow events. Trees are well adapted to surviving in conditions of environmental stress connected with abrupt transport and deposition of sediment from debris flows. Numerous wounds, tilting and bending of alder trees caused by debris flows only very rarely cause the death of trees. By dating scars and dating the time of alder tilting (through the analysis of annual rings), we have determined the frequency of debris flows occurring at the mouth of the Daozhao valley. In 1980–2012 within the studied debris-flow fan and the Daozhao gully, 2 large debris flow events occurred (1996, 2005) and some smaller events were probably recorded every 2–3 years.

Alluvial Fan Alteration Due to Debris-Flow Deposition, Incision, and Channel Migration at Forest Falls, California

2021 ◽  
Vol 27 (1) ◽  
pp. 29-41
Author(s):  
Kerry Cato ◽  
Brett Goforth
Keyword(s):  
Debris Flow ◽  
Water Content ◽  
Debris Flows ◽  
Dynamic Instability ◽  
Debris Avalanche ◽  
Alluvial Fan ◽  
Multiple Sources ◽  
Sediment Delivery ◽  
Field Methods ◽  
San Bernardino Mountains

ABSTRACT Historical patterns of debris flows have been reconstructed at the town of Forest Falls in the San Bernardino Mountains using a variety of field methods (mapping flow events after occurrence, dendrochronology evidence, soil chronosequences). Large flow events occur when summer thunderstorms produce brief high-intensity rainfall to mobilize debris; however, the geomorphic system exhibits properties of non-linear response rather than being a single-event precipitation-driven process. Previous studies contrasted the relative water content of flows generated by varying-intensity summer thunderstorms to model factors controlling flow velocity and pathway of deposition. We hypothesize that sediment discharge in this geomorphic system exhibits multiple sources of complexity and present evidence of (1) thresholds of sediment delivery from sources at the higher reaches of bedrock canyons, (2) storage effects in sediment transport down the bedrock canyons, and (3) feedbacks in deposition, remobilization, and transport of sediment across the alluvial fan in dynamic channel filling, cutting, and avulsion processes. An example of the first component occurred in March 2017, when snowmelt generated a rapid translational landslide and debris avalanche of about 80,000 m3; this sediment was deposited in the bedrock canyon but moved no farther down gradient. The second component was observed when accumulation of meta-stable sediments in the bedrock canyon remained in place until fluvial erosion and subsequent debris flow provided dynamic instability to remobilize the mass downstream. The third component occurred on the alluvial fan below the bedrock canyon, where low-water-content debris flows deposited sediments that filled the active channel, raising the channel grade level to levee elevation, allowing for subsequent spread of non-channelized flows onto the fan surface and scouring new channel pathways down fan. A conceptual model of spatial and temporal complexities in this debris-flow system is proposed to guide future study for improved risk prediction.

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.

scholarly journals Natural Disasters Versus Anthropogenic Activities in Nepal Himalayas: Case Study from Ghatte Khola , Myagdi

2019 ◽  
Vol 1 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Narayan Gurung
Keyword(s):  
Debris Flow ◽  
Natural Disasters ◽  
Debris Flows ◽  
Flash Flood ◽  
Anthropogenic Activities ◽  
Alluvial Fan ◽  
Electric Power Station ◽  
Natural Dynamics ◽  
The Right

In the Himalayas, geo-hazards are natural events occurring more or less frequently and of a greater or lesser magnitude. But when natural hazards affect people and property, then it becomes disasters. It’s believed that natural disasters as such do not exist. Everything is just natural hazard and anything can turn into disasters due to anthropogenic activities. Thus, natural phenomenons are hazards while disasters are anthropogenic. In this regard, a case study was being conducted in the Ghatte Khola (Dana) of Myagdi District in Western Central Nepal, where in a context of growing population and haphazard construction of infrastructures, natural dynamics have turned into disasters. The Ghatte Khola is an intermittent, right bank tributary of the Kali Gandaki, which behaves occasionally as a debris flow, in relation with slope instabilities that affect its upstream catchment. The debris flows are usually triggered during heavy cloudbursts, and can cause damages and losses downstream, along the wide alluvial fan built at the tributary junction and upon which Dana village (Myagdi District) is settled. Inhabitants are aware of this ephemeral, yet threatening behaviour of the stream that may also affect the Kali Gandaki valley upstream from the confluence (Lat. 28°32'22" N and Long. 83°39'03" E). The Ghatte Khola is often affected by debris flows bringing sediment fluxes that are eroding its banks every year. A motor bridge was being built over Ghatte Khola near the confluence with Kali Gandaki and further, a large electric power station is being built on the right bank of Ghatte Khola. Sadly, the bridge was washed away by the flash flood in Ghattekhola on 25th May 2019. This study was focused on vulnerability of these man made infrastructures and their future on Ghatte Khola debris flow dynamics, with hazard that might occasionally transform into disaster.  

Activity Degree Evaluation of Glacial Debris Flow along International Karakorum Highway (KKH) Based on Fuzzy Theory

2011 ◽  
Vol 261-263 ◽  
pp. 1167-1171 ◽  
Author(s):  
Zhi Quan Yang ◽  
Ying Yan Zhu ◽  
D.H.Steve Zou ◽  
Li Ping Liao
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Evaluation Method ◽  
Fuzzy Theory ◽  
Alluvial Fan ◽  
Vegetation Coverage ◽  
Fuzzy Evaluation ◽  
Effective Evaluation ◽  
Catchment Areas

The area of international Karakorum Highway(KKH), is an area with dense and frequent glacial debris flow disasters due to unique geology, geomorphology and landform conditions,which connects northern Pakistan with northwestward China. After in situinvestigation and analyze the present data of these glacier debris flow, by using the fuzzy evaluation method, we selected seven factors,such as occurrence frequency,catchment areas,volumes of alluvial fan,estimated outflow of every time,vegetation coverage, slope and altitude, as main factors for evaluating the activity degree of 8 chosen representative glacier debris flows along KKH. According to the evaluation results,which are showed a good correspond with the practical situation, it can conclude that the fuzzy evaluation method based on the fuzzy mathematics theory is an very effective evaluation method in dealing with glacial debris flow with lots of fuzzy factors,i.e. this method is available for evaluating the activity degree of glacier debris flows.

Sign in / Sign up

Export Citation Format

Share Document