Potential Debris Flow Research Articles

Effects of Bed Hydrophobicity on Post‐Fire Debris Flow Entrainment and Momentum Growth

AbstractForest wildfires leave vast areas with burned topsoil that is water repellent, susceptible to erosion by surface runoff and a potential source of debris flow. To mitigate post‐fire debris flow hazards, debris resisting barriers are usually constructed in the flow path. However, the fundamental interaction mechanisms of debris flow on a water repellent bed and the momentum exchange process that governs the destructive potential of debris flows have yet to be elucidated. This study investigates the influence of bed sediment hydrophobicity on entrainment by debris flows and the impact force on a downstream barrier using a series of physical flume tests. Bed sediment with increasing contact angles (50°–130°) were used to model bed hydrophobicity from wettable to hydrophobic conditions, and volumetric water content (0%–30%) to simulate the natural unsaturated condition after rainfall in fire‐burned hillslopes. Compared to a wettable bed, a hydrophobic bed exhibits a failure pattern with slab‐by‐slab entrainment and en masse failure with a sixfold increase in the average erosion depth. A new dimensionless number is proposed to quantify the effects of contact angle on soil erosion. The flow momentum increases up to 21% after entrainment of hydrophobic bed compared to non‐erodible bed. The peak impact force on the downstream barrier can increase up to 80% for hydrophobic bed as a consequence of momentum gains after entrainment. The hydrodynamic coefficient for estimating impact force reveals the inadequacy of current design criteria of debris resisting barriers for fire‐prone vegetated hillslopes, suggesting further investigations are needed.

Rheology of debris flow materials is controlled by the distance from jamming

Debris flows are dense and fast-moving complex suspensions of soil and water that threaten lives and infrastructure. Assessing the hazard potential of debris flows requires predicting yield and flow behavior. Reported measurements of rheology for debris flow slurries are highly variable and sometimes contradictory due to heterogeneity in particle composition and volume fraction ([Formula: see text]) and also inconsistent measurement methods. Here we examine the composition and flow behavior of source materials that formed the postwildfire debris flows in Montecito, CA, in 2018, for a wide range of [Formula: see text] that encapsulates debris flow formation by overland flow. We find that shear viscosity and yield stress are controlled by the distance from jamming, [Formula: see text], where the jamming fraction [Formula: see text] is a material parameter that depends on grain size polydispersity and friction. By rescaling shear and viscous stresses to account for these effects, the data collapse onto a simple nondimensional flow curve indicative of a Bingham plastic (viscoplastic) fluid. Given the highly nonlinear dependence of rheology on [Formula: see text], our findings suggest that determining the jamming fraction for natural materials will significantly improve flow models for geophysical suspensions such as hyperconcentrated flows and debris flows.

Evaluating the post-earthquake landslides sediment supply capacity for debris flows

Earthquake-triggered landslides provide sufficient loose material for the formation of subsequent debris flow events in earthquake-affected catchments. The landslides sediment supply capacity (SSC) for debris flows plays an important role in post-earthquake sediment transportation, which is influenced by landslide location during different post-earthquake periods. In this study, the logarithmic slope–area diagram was used to distinguish hillslope and channel processes in catchments affected by the Wenchuan earthquake, adopting a threshold between hillslopes and channels set at 1 km2. In comparison with the existing structural sediment delivery ratio (SDR), it was found that the SSC assessed using the SDR showed a decreasing trend of power exponent as distance increased, effectively eliminating the impact of earthquake-triggered sediment supply. To efficiently assess the SSC of post-earthquake landslides for debris flows, we proposed a novel dimensionless index, namely Mean Landslide Sediment Delivery Ratio (MLSDR), by considering the impact of earthquakes and eliminating the impact of catchment area. It was found that, the SSC of coseismic landslides assessed by the MLSDR in catchments affected by the Wenchuan earthquake could better reflect seismic impact, with higher values concentrated along the seismogenic fault of the earthquake, thereby highlighting the satisfactory applicability of the method in the Wenchuan earthquake-affected area. Moreover, it was found that the proposed index had a reasonable corresponding relationship with debris flow development in Wenchuan earthquake-affected catchments, mainly for values of 0.2 ≤ MLSDRout ≤ 2.25 and 0.3 ≤ MLSDRchannel ≤ 4.5, which could help identify potential debris flow development. The controlling factors of long-term changes in coseismic and post-earthquake SSC in the Wenchuan earthquake-affected region were assessed. It was found that SSC was controlled by earthquakes during first three years and subsequently controlled by precipitation and grain composition. This study will strengthen the understandings of the long-term evolution of post-earthquake debris flow.

Numerical analysis of debris flows along the Sichuan-Tibet railway based on an improved 3D sphere DDA model and UAV-based photogrammetry

This paper develops an improved three-dimensional sphere discontinuous deformation analysis (SDDA) model and uses UAV-based photogrammetry to enable SDDA to numerically analyze potential long-runout debris flows in Zheduotang area along the Sichuan-Tibet railway. First, the original SDDA is improved by proposing a sphere-sphere bonding algorithm to bond spheres with tetrahedral layout to form four-sphere clusters to approximate non-sphere particles in debris flow. Second, the capacity of the improved SDDA is verified by comparing modelling results with four groups of laboratory tests of granular flow. Third, UAV-based photogrammetry is used to obtain the real morphology of the extremely complex terrain surface of Zheduotang area which is finally transferred into a large number of triangular faces as the fixed boundary faces of SDDA. Then, three potential debris flow scenarios on this terrain surface are numerically studied, and some suggestions for engineering disaster prevention are drawn. Model performance shows that, the improved SDDA is a feasible tool to simulate debris flows. With the help of UAV-based photogrammetry, it shows significantly helpful for geohazard prevention for infrastructures in mountainous areas like the Sichuan-Tibet railway.

Watershed landslide evolution combined with topographic factors to delineate the spatio-temporal distribution of sediment sources in central Taiwan

This study uses topographical factors to quantitatively describe the uplift amplitude of the plate movement, collects and analyzes the long-term series of rainfall, earthquakes, landslides and debris flows in watersheds from 1993 to 2019, explores the evolution mechanism of landslides, and uses conceptual models to map the areas prone to occurrence of potential debris flows in central Taiwan. Results show that the topographic factors of a watershed can effectively reflect the concavity index (θ) of the crustal uplift, and the spatial distribution of the concavity index in the watershed can be easily estimated. Combining the spatial distribution of concavity index and stream order, a watershed-scale potential debris flow map can be obtained. According to the interpretation rate change of the relationship between the concavity index and the watershed collapse rate, we can understand the occurrence time of landslides and/or debris flows, as well as the sediment transport dynamics of the watershed. The change of the interpretation rate of the concavity index to the collapse rate can be used as a guideline for the establishment of a debris flow warning system.

Evaluating landslide response in a seismic and rainfall regime: a case study from the SE Carpathians, Romania

Abstract. There have been many studies exploring rainfall-induced slope failures in earthquake-affected terrain. However, studies evaluating the potential effects of both landslide-triggering factors – rainfall and earthquakes – have been infrequent despite rising global landslide mortality risk. The SE Carpathians, which have been subjected to many large historical earthquakes and changing climate thus resulting in frequent landslides, comprise one such region that has been little explored in this context. Therefore, a massive (∼9.1 Mm2) landslide, situated along the river Bâsca Rozilei, in the Vrancea seismic zone, SE Carpathians, is chosen as a case study area to achieve the aforesaid objective (evaluating the effects of both rainfall and earthquakes on landslides) using slope stability evaluation and runout simulation. The present state of the slope reveals a factor of safety in a range of 1.17–1.32 with a static condition displacement of 0.4–4 m that reaches up to 8–60 m under dynamic (earthquake) conditions. The groundwater (GW) effect further decreases the factor of safety and increases the displacement. Ground motion amplification enhances the possibility of slope surface deformation and displacements. The debris flow prediction, implying the excessive rainfall effect, reveals a flow having a 9.0–26.0 m height and 2.1–3.0 m s−1 velocity along the river channel. The predicted extent of potential debris flow is found to follow the trails possibly created by previous debris flow and/or slide events.

Investigation of potential debris flows above the Koroška Bela settlement, NW Slovenia, from hydro-technical and conceptual design perspectives

Investigation of potential debris flows above the Koroška Bela settlement, NW Slovenia, from hydro-technical and conceptual design perspectives

Assessment and Analysis of a Rainfall–Time-Lagging Water-Related Disaster in Mountainous Areas

Both global climate change and human activities are continuously impacting the abruptness and frequency of water-related natural disasters such as flash floods, debris flows, and landslides in mountainous areas, greatly threatening the safety of lives and properties. A recent rainfall-induced debris flow event happened on July 6, 2020 in the Chenghuangmiao Gully, in Sichuan Province, China, resulting in severe damage to buildings at the outlet. An integrated analysis of the consequence and triggering mechanism of this debris flow event was conducted with hydrologic information, topographic details, vegetation regimes, and drone aerial imagery. The result shows that the entire runout of the debris flow differs from that of common ones (debris flow and rainfall were highly related and synchronized), which happened 4 h after the stop of the rainfall. The hysteretic feature increases the difficulty of the prediction and warning of the debris flow due to lack of a responsible triggering mechanism. The hillslope surface is well covered by vegetation, hindering regular observation and cleaning up of long-term deposited wood and sediment debris. This effect increases the crypticity and abruptness of potential debris flows. With field evidence and analysis, it is speculated that long-term accumulative processes of dead wood sand sediment deposition formed a small-scale debris dam, and the continuous water release from the watershed led to dam breaching, subsequently triggering the initiation of the debris flow. Multiple steps distributing along the gully of an average slope of 15.65° contributed to the amplification of the debris flow once the breach of the upstream wood and sediment dam occurred. Along the gully, small-scale landslide scars can be observed, possibly amplifying the scale of the debris flow and disaster impact. This debris event gives a lesson of necessary demands of predicting and managing the risks of a low-frequency debris flow non-synchronized with rainfall events.

A novel approach to simulating debris flow runout via a three-dimensional CFD code: a case study of Xiaojia Gully

Extensive models used in debris flow runout simulations are two-dimensional with many limitations. Considering these limitations, a new three-dimensional computational fluid dynamics (CFD) code based on the finite difference method (FDM) was introduced to simulate debris flow runouts. The unique fractional area-volume obstacle representation (FAVOR), true-volume of fluid (Tru-VOF), and the renormalized group (RNG) model in the 3D CFD code were used to tackle mesh processing, free surface tracking, and turbulence, respectively. The RNG model has great performance in describing low-intensity flows and flows with strong shear regions. In addition, the 3D CFD modeling considers the vertical mobility of debris flow, which offers higher simulation accuracy compared to 2D approaches. Through simulating a case and a mesh size study, the accuracy of the model was validated and the optimal mesh size of Xiaojia Gully debris flow model was obtained, respectively. The affected areas, runout distances, deposition depths, and velocities of potential debris flows in Xiaojia Gully were acquired by adopting the present model. The simulation results show that debris flows with return periods of 50 years, 100 years, and 200 years will threaten the lives and safety of residents and their property in Xiaojia Gully. A sensitivity analysis was used to evaluate the influences of rheological parameters on this model, further verifying the rationality of the selected parameters. In general, the present model can scientifically and accurately simulate debris flows on irregular terrain and can be employed for similar risk management and engineering designs.

Revealing the Importance of Capillary and Collisional Stresses on Soil Bed Erosion Induced by Debris Flows

AbstractClimate change is increasing the frequency of extreme rainfall events and the snow cover to melt at high altitudes, which may exacerbate the threat posed by debris flows. Soil bed erosion, the process by which the bed material fails under loadings from a debris flow, is perhaps the most important momentum exchange process that governs the destructive potential of debris flows. Existing erosion theories adopt saturated soil mechanics to describe the failure of soil bed and place a strong emphasis on the basal friction induced shear stress as the driving mechanism. However, soil beds in nature are rarely saturated and field observations have hinted at the importance of collisional stresses as a driving mechanism. In this study, an unsaturated soil mechanics framework is used to characterize soil bed erosion by collisional flows. Experiments were conducted to model the erosion of unsaturated sandy beds with a wide range of initial matric suction values, which is a measure of capillary stresses, by gravel flows. Contrary to the existing literature, the rate of erosion does not increase linearly but demonstrates a parabola‐like relationship with the bed water content because the shear strength of unsaturated soil is governed by capillary stresses. The importance of collisional stresses on soil bed erosion is demonstrated by a newly proposed dimensionless number. Findings indicate that existing erosion models largely underestimate channel bed erosion, especially for soil beds with low water content, and stress the importance of hydro‐mechanical coupling to advance the current state of debris flow hazard delineation.

Debris-Flow and Debris-Flood Susceptibility Mapping for Geohazard Risk Prioritization

ABSTRACT Regional-scale assessments for debris-flow and debris-flood propagation and avulsion on fans can be challenging. Geomorphological mapping based on aerial or satellite imagery requires substantial field verification effort. Surface evidence of past events may be obfuscated by development or obscured by repeat erosion or debris inundation, and trenching may be required to record the sedimentary architecture and date past events. This paper evaluates a methodology for debris-flow and debris-flood susceptibility mapping at regional scale based on a combination of digital elevation model (DEM) metrics to identify potential debris source zones and flow propagation modeling using the Flow-R code that is calibrated through comparison to mapped alluvial fans. The DEM metrics enable semi-automated identification and preliminary, process-based classification of streams prone to debris flow and debris flood. Flow-R is a susceptibility mapping tool that models potential flow inundation based on a combination of spreading and runout algorithms considering DEM topography and empirical propagation parameters. The methodology is first evaluated at locations where debris-flow and debris-flood hazards have been previously assessed based on field mapping and detailed numerical modeling. It is then applied over a 125,000 km2 area in southern British Columbia, Canada. The motivation for the application of this methodology is that it represents an objective and repeatable approach to susceptibility mapping, which can be integrated in a debris-flow and debris-flood risk prioritization framework at regional scale to support risk management decisions.

Debris Flow Numerical Simulation Model Comparison with Field Events in Kuala Kubu Baru and Lentang, Malaysia

Debris flow is one of Malaysia’s natural disasters which could cause casualties and serious infrastructure damage. Precisely predicting the factors associated with the occurrence of debris flow such as the run-out lengths, velocities and thickness of alluvial deposits can greatly mitigate damage, minimize or even avoid the aftermaths of the occurrence. Applying numerical simulation models explaining debris flow deposition would be a valuable tool in forecasting potential debris flow activity and providing criteria for designing protective measures. Comprehensive studies of available records of past debris flow events from relevant sources and site investigations have been carried out in order to assemble field information for the particular debris flow event in Malaysia. A number of calamitous debris flow events occurred in Malaysia have been closely observed and studied. The well-documented events, i.e. Lentang and Kuala Kubu Baru debris flow disasters occurred on 2nd November 2004 and 10th November 2003, respectively were simulated using the Kanako 2D (Ver.2.04) simulation model software. The results obtained from the numerical simulation model were compared with the real events in order to evaluate their predictive capabilities. The results showed an accuracy of more than 93% was obtained from the simulation model as compared to the real in-situ measurements. A positive simulation result will become a valuable method to predict potential debris flow hazard behavior of the same type and characteristics.

Debris flow disaster risk analysis and modeling via numerical simulation and land use assessment

To mitigate the risk of debris flows, quantitative risk assessments for different land use types are quite significant. However, with respect to debris flows, no sound relationship has so far been established between risks and different land use types. This study developed a method of debris flow risk assessment by incorporating numerical simulations with land use types. First, the key debris flow intensities for different return periods, including movement velocities and maximum flow depths, were identified via numerical simulations. Second, a debris flow hazard classification model based on a combination of the debris flow intensity and the return period was established to assess debris flow hazard degree. Then, the land use distribution within the inundated areas was itemized via the interpretation of remote sensing and field surveys, and the debris flow vulnerability was determined by the degree of functional damage or the cost of recovery of land uses caused under a given hazard. Finally, the potential debris flow risk zones were identified and mapped by combining debris flow hazard and vulnerability. The methodology was applied and verified in a small debris flow watershed in China. The proposed methodology can be performed effectively to conduct debris flow risk analysis and can be widely employed for debris flow mitigation.

Estimation of Debris Flow Sedimentation Volume Through Numerical Modelling

Implementation of potential debris flow hazard in Malaysia has been conducted by JabatanKerja Raya (JKR) in 2011. However, evaluation of this hazard level cannot deny the consequent to the nearest facilities. Thus, run-out analysis based on numerical modelling is easiest and competent way to evaluate the risk level. This paper presents a study on debris flow sedimentation volume with and without sabo dam by numerical simulation using Kanako 2D software. Kanako 2D software is widely being used in Japan and it is equipped with graphical user interface (GUI). A crossed verification upon numerical modelling and actual field data collection, and mitigation situation model that include sabo dam has been conducted. Results showing that Kanako 2D software have a precise output where the sedimentation volume is slightly higher around 5-15 %. It also proven that sabo dam can reduce the impact of debris flow because it can bear the sedimentation volume about 91%. In speeding up the process of setting landform in Kanako 2D, it recommended to use GIS to generate appropriates data. Thus, a laser scanning of topographical data is required.

A novel dynamic impact pressure model of debris flows and its application on reliability analysis of the rock mass surrounding tunnels

Assessing the influence of the impact pressure exerted on surrounding rock mass by potential debris flows is one of the challenges in a mountain tunnel construction project. This paper proposes an effective mathematical model for the assessment of impact pressure exerted by debris flows on obstacles. The characteristics of the new model are analyzed, and the parameters determination method for the new model are deduced. Also, a new method for dynamic reliability analysis of the rock mass surrounding tunnels is proposed and is constituted into three key steps. First, by inputting impact pressure of debris flows generated by the aforementioned new model, the FLAC3D is used as the dynamic analysis engine to obtain the time-varying stress distribution of surrounding rock mass during the impact of debris flow. Second, the factor of safety (FOS) contours of surrounding rock mass are generated based on element states using the maximum tensile stress criterion and the Mohr-Coulomb yield criterion. Third, by using the time-varying contours of the FOS, a failure probability and a reliability index are obtained from a reliability perspective. A case study shows the complete analysis process and confirms the effectiveness of the above methodology. In sum, this paper provides new ideas, new methods, and a reference example for evaluating the influence of dynamic impact exerted by debris flows on the rock mass surrounding tunnels.

Debris Flow Susceptibility Assessment and Runout Prediction: A Case Study in Shiyang Gully, Beijing, China

At 14:00 on 18 June 2017, floods occurred in Shiyang gully at the junction of Beijing and Hebei Province, China. The floods put 12 people at risk, 6 of whom died. After the occurrence of the floods, the environment in Shiyang gully has undergone tremendous changes. There are many loose residual materials in the watershed. Therefore, it was necessary to evaluate the debris flow susceptibility of Shiyang gully after the disaster. The factor analysis method, entropy weighting method and geomorphic information entropy method were used to evaluate the debris flow susceptibility of each sub-watershed in Shiyang gully. By comparison with the technical standard published by the China Ministry of Lands and Resources, it was found that the susceptibility assessment results are not ideal. To improve the accuracy of the assessment results, we used a comprehensive method. The accuracy of the susceptibility assessment obtained by the comprehensive method is 87.5%. This accuracy shows that the comprehensive method is applicable to the susceptibility assessment of debris flows in this region. To predict the runout path of potential debris flows in four sub-watersheds with very high susceptibility, the authors used the SFLOW software developed by Jilin University to simulate the debris flow hazards. Combined with the on-site investigation data, debris flows in the four sub-watersheds were simulated at 10-, 20-, 50-, and 100-year recurrence intervals. The obtained runout path could provide some guidance and reference for the avoidance of disasters and treatment of debris flows.

Characteristics of a Debris Flow Disaster and Its Mitigation Countermeasures in Zechawa Gully, Jiuzhaigou Valley, China

On 8 August 2017, an Ms 7.0 earthquake struck Jiuzhaigou Valley, triggering abundant landslides and providing a huge source of material for potential debris flows. After the earthquake debris flows were triggered by heavy rainfall, causing traffic disruption and serious property losses. This study aims to describe the debris flow events in Zechawa Gully, calculate the peak discharges of the debris flows, characterize the debris flow disasters, propose mitigation countermeasures to control these disasters and analyse the effectiveness of countermeasures that were implemented in May 2019. The results showed the following: (1) The frequency of the debris flows in Zechawa Gully with small- and medium-scale will increase due to the influence of the Ms 7.0 Jiuzhaigou earthquake. (2) An accurate debris flow peak discharge can be obtained by comparing the calculated results of four different methods. (3) The failure of a check dam in the channel had an amplification effect on the peak discharge, resulting in a destructive debris flow event on 4 August 2016. Due to the disaster risk posed by dam failure, both blocking and deposit stopping measures should be adopted for debris flow mitigation. (4) Optimized engineering countermeasures with blocking and deposit stopping measures were proposed and implemented in May 2019 based on the debris flow disaster characteristics of Zechawa Gully, and the reconstructed engineering projects were effective in controlling a post-earthquake debris flow disaster on 21 June 2019.

Numerical assessment for the efficiencies of check dams in debris flow gullies: A case study

Quantitative assessment for the efficiencies of check dams is necessary for the purpose of reducing the risk of potential debris flow disasters. In this paper, an improved finite difference model is adopted to assess the efficiency of the check dam in Dagou debris flow gully, Gansu Province, China. Unlike other numerical models, the improved model can simultaneously consider bed entrainment and the impeding effect of check dams, so it can reflect the interaction between check dams and debris flow dynamics. The results show that the existing 10 m check dam may only be sufficient to prevent a debris flow with less than 0.8 times the volume of the catastrophic event occurred in this gully in 2013. Otherwise, a higher check dam should be constructed in order to prevent a larger event. The location of a check dam has significant influence on the dynamics of the debris flow. Generally, a check dam constructed in the upper part of the gully performs better in controlling bed entrainment and the discharge. Comparing with the locations in downstream, the dam site located in upstream of this gully seems to be a better choice in terms of both efficiency and engineering quantity.

PHASE TRANSITIONS IN THE DEBRIS FLOW GEOSYSTEMS

The evolution of a geosystem can be described as a continuous process. Stages of geosystems evolution: the formation of a massif of loose rocks in a site, its transformation to potential massifs due to diagenesis and morphogenesis, the occurrence and movement of a debris flow, unloading of large-block and then – fine-dispersed material and the passage of a debris-flow. Each stage of the geosystem evolution can be described as a transition from one subsystem level to another and the change of states of the system – as phase transitions of first kind. Physical processes occurring within the system cause it. The most important transition is from a solid state (potential debris-flows massif-conditionally homogeneous solid having an internal structure) to a and mudflow (quasi-liquid state). The transition of a potential massif to another phase state is due not only to external factors (the inflow of free water into the site), but also internal: the mineralogical composition of rocks of the potential massif (the content of hydrophilic minerals). The most important parameter that determines both the connectivity of the soils of the potential massif and the conditions of its transition to the liquid phase are the electric forces at the contacts between the elements of the mineral skeleton (soil particles). Electrical forces provide a connection between the ground particles. The liquid component of the mudflow is traditionally described as a debris-flow suspension, but a coherent and mudflow is not a suspension. A suspension is a dispersed system consisting of a solid dispersed phase and a liquid dispersion medium in which the solid is uniformly distributed as minute particles in a liquid substance in suspension. Such a medium is not able to carry over long distances block-boulder material having a higher density than the suspension. Nevertheless, a coherent and mudflow is a conditionally single-phase system in which water is predominantly in a molecular bound state. The physical analogue of a coherent and mudflow is a colloidal system, since in a connected village fine-earth particles are distributed in a continuous dispersion medium and do not precipitate. This circumstance is key in the physical modeling of connected debris-flows and mudflows.

SEMI-QUANTITATIVE ASSESSMENT OF DEBRIS FLOW RISKS ON HIGHWAYS

Semi-quantitative methodology for determining the category of debris flow risks of transport infrastructure facilities is designed to detect potential debris flow vulnerable parts of highways and to assess the effects of debris flows. The results obtained through this methodology can be used to justify the sequence of repair works or the construction of means of engineering protection, monitoring measures and alert system. The technical expertise of debris flow vulnerable tracks on the Black Sea coast of the Krasnodar Territory and the calculation of flow parameters allow ranking of the formation factors in relation to each other. Each factor is awarded points in accordance with the display intensity and the impact on the road. The mutual influence of individual factors is determined by integration which is performed by combination of summation and multiplication. The main criteria of a debris flow formation are: steepness of slopes and riverbeds of watersheds, the amount of destroyed rocks elements (erosion process development degree; presence, amount and location of segments with large reserves of deposited drift), sources of the water component of flows, heights of the area, geological structure, plant cover, erosion and weathering processes intensity; information about previous mudflows (frequency of occurrence, volume of removals). The technical state of anti-mudflow and engineering protection building structures also plays an essential role in the risk assessment. Due to some damage accumulated over time there is decrease in strength and stability, the possibility of construction destruction increases. The previous sediments and the construction parts involvement creates a breakthrough wave, a significant increase in the mudflow and therefore the damage.