The impact of human activities on the occurrence of mountain flood hazards: lessons from the 17 August 2015 flash flood/debris flow event in Xuyong County, south-western China

Gan, Bin-rui; Liu, Xingnian; Yang, Xing-guo; Wang, Xiekang; Zhou, Jia‐wen

doi:10.1080/19475705.2018.1480539

Cited by 38 publications

(20 citation statements)

References 42 publications

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“…The dense distribution of buildings and infrastructure results in a high concentration of population in the area, which increases the potential for catastrophic damage from water-induced hazards. The impact of human activities on debris flow disasters includes two main aspects: indirect effects and direct effects (Gan et al, 2018). The former mainly emphasizes damage to the natural environment, such as the unreasonable exploitation and utilization of vegetation, soil, and water resources.…”

Section: Discussionmentioning

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: Discussionmentioning

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 scenario simulations of flash floods have been performed using the Mike Flood and Flood Area system by some researchers [20,21]. These studies have mainly been conducted on flash flood ditches or at a watershed scale [22,23]. Finally, some researchers have explored the spatiotemporal patterns and driving forces of flash floods [24,25].…”

Section: Introductionmentioning

confidence: 99%

Spatiotemporal Characteristics and Driving Force Analysis of Flash Floods in Fujian Province

Xiong

Quan

Fan

et al. 2020

IJGI

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Flash floods are one of the most destructive natural disasters. The comprehensive identification of the spatiotemporal characteristics and driving factors of a flash flood is the basis for the scientific understanding of the formation mechanism and the distribution characteristics of flash floods. In this study, we explored the spatiotemporal patterns of flash floods in Fujian Province from 1951 to 2015. Then, we analyzed the driving forces of flash floods in geomorphic regions with three different grades based on three methods, namely, geographical detector, principal component analysis, and multiple linear regression. Finally, the sensitivity of flash floods to the gross domestic product, village point density, annual maximum one-day precipitation (Rx1day), and annual total precipitation from days > 95th percentile (R95p) was analyzed. The analytical results indicated that (1) The counts of flash floods rose sharply from 1988, and the spatial distribution of flash floods mainly extended from the coastal low mountains, hills, and plain regions of Fujian (IIA2) to the low-middle mountains, hills, and valley regions in the Wuyi mountains (IIA4) from 1951 to 2015. (2) From IIA2 to IIA4, the impact of human activities on flash floods was gradually weakened, while the contribution of precipitation indicators gradually strengthened. (3) The sensitivity analysis results revealed that the hazard factors of flash floods in different periods and regions had significant differences in Fujian Province. Based on the above results, it is necessary to accurately forecast extreme precipitation and improve the economic development model of the IIA2 region.

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“…Protection and stabilization structures, sediment retention works (e.g., check dams, sediment trapping dams) and siltation and discharge control works (drainage channels, grilled dams, sedimentation basins, step-pool systems and others) are the constructions that are commonly used to regulate the formation and movement of debris flows [44]. However, in the mountainous areas of southwestern China, some previous hazard prevention and reduction construction measures did not effectively work and increased the risk to human beings [45][46][47]. One of the main reasons for this is that the magnitude of the design event was underestimated because the excess supply of solid materials was not considered.…”

Section: Introductionmentioning

confidence: 99%

Contribution of Excessive Supply of Solid Material to a Runoff-Generated Debris Flow during Its Routing Along a Gully and Its Impact on the Downstream Village with Blockage Effects

Chen

Liu

Wang

et al. 2019

Water

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On 8 August 2017, a runoff-generated debris flow occurred in the Puge County, Sichuan Province of southwestern China and caused huge property damage and casualties (25 people died and 5 people were injured). Emergency field investigations found that paddy fields, dry land, residential buildings and roads suffered different degrees of impact from the debris flow. This paper reveals the formation process of the debris flow by analyzing the characteristics of rainfall precipitation and sediment supply conditions in the study area and it approaches the practical application of hazard prevention and mitigation constructions. Doppler weather radar analysis indicates that a very high intensity rainfall occurred in the middle and upper zones of the basin, illustrating the importance of enhancing rainfall monitoring in high-altitude areas. The abundant supply of deposits in gully channels is among the significant causes of a transformation from mountain floods to large-scale debris flows. It was also found that the two culverts played an important role in the movement affecting the processes of debris flows which has substantially aggravated the destructive outcome. The excessive supply of solid material and local blockage with outburst along a gully must receive significant attention for the prediction of future debris flows, hazard prevention and mitigation measures.

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The impact of human activities on the occurrence of mountain flood hazards: lessons from the 17 August 2015 flash flood/debris flow event in Xuyong County, south-western China

Cited by 38 publications

References 42 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

Spatiotemporal Characteristics and Driving Force Analysis of Flash Floods in Fujian Province

Contribution of Excessive Supply of Solid Material to a Runoff-Generated Debris Flow during Its Routing Along a Gully and Its Impact on the Downstream Village with Blockage Effects

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