bluuebunny/crossref_metadata_2025 huggingface dataset:
Small-scale study of Debris-Flows Interactions with a Lateral Debris Basin and Crossings: The Manival Torrent case study
Authors: Alliau Damien , Piton Guillaume , Chambon Guillaume , Drouet Anne-Sophie , Koulinski Vincent , Kuss Damien , Laigle Dominique , Mano Vincent , Misset Clément , Peteuil Christophe , Roux Sébastien , Verry Pierre
Published: August 2023

Small-scale models are useful tools to study the interactions between debris flows and structures and channels. Small-scale modelling of debris flows remains however complicated because of the complex rheology and scaling challenges of these geophysical processes. An on-going study of a debris basin and the downstream channel where two fords and a bridge are located is presented in this extended abstract. The studied torrent is the Manival catchment, located near Grenoble in France. We present the catchment features, the scientific questions studied, some preliminary calibration results describing the mixtures used to model debris flows as well as results from three debris-flood and two debris-flow runs. In essence, the model highlighted that the structure enable a large share of the bedload transport to pass downstream. Debris flows can be more or equally trapped depending on their rheology which controls the surges dynamics and the deposition slope in the debris basin.
Simulations of the occurrence of runoff-generated debris flows by means of hydrological models in headwater rocky basins
Authors: Bernard Martino , Barbini Matteo , Battistel Leonardo , Berti Matteo , Simoni Alessandro , Gregoretti Carlo
Published: August 2023

The simulation of the occurrence of the runoff-generated debris flows can be approached by means of hydrological models. In this work, we show that a rainfall-runoff model designed for the simulation of runoff in headwater rocky basins can capture both the transit timing of the first debris-flow surge and its hydrograph. We successfully compared the stage hydrograph of debris flows with that of the simulated runoff in two headwater rocky basins of Dolomites.
The Rosetta Stone Project – Integrating experimental results on debris flow mechanics across the scales: Next results
Authors: Bowman Elisabeth T. , Fawley Amanda , Kaitna Roland , Li Shuai , McArdell Brian , McElwaine Jim , Sanvitale Nicoletta , Take W. Andrew , Tauskela Lisa , Taylor-Noonan Alex , Zhao Yuting
Published: August 2023

We present the combined efforts of a research network designed to address the many challenges in the experimental modelling of debris flow phenomena. The approach has been to use apparatuses of different functional arrangement and at different scale with identical and commonly sourced flow materials from the highly idealised (dry, coarse and uniform) to the highly complex (well graded, segregating, fluid saturated). Here we briefly present some key findings of the network and point to the research questions that are currently being addressed. This complementary view of experimental debris flows helps to constrain methodological artefacts/scale effects and to identify key processes responsible for the diverse appearance and often high mobility of debris flows.
Hydraulic model test on channel shifting and yielding woody debris on the fan after sediment disaster in the past
Authors: Hashimoto Kenji , Watabe Haruki , Kisa Hiroshi , Hoya Tomoyuki , Itoh Takahiro , Watanabe Yasuharu , Akahori Ryosuke
Published: August 2023

The re-movement of sediment and woody debris in torrents after huge sediment transport in the past could cause new flood and sediment disasters due to heavy rainfall events. However, it is not clear how re-movement of logs effects on bed variations such as bars and river channel divergence. In present study, hydraulic model tests were carried out referring to the magnitude of floods, that was over the plan size, in Tottabetsu River basin in August in 2016. These tests include different magnitudes of flood, suppling logs from bed/side bank erosion, and existence of sabo facilities. The key results were as follows: The presence of logs by bed/side bank erosions influences on the patterns of flows and sediment transport, because deposition of logs affects formation of bars. Difference of the magnitudes of the floods affects the activeness of the interaction between logs and sediment transport. In additions, the locations and slits of the sabo dam need to consider hydraulic conditions and characteristics of woody debris for appropriate control of sediment and woody debris.
Pilot study to explain runout distances of debris flow and immature debris flow considering depositing rate
Authors: Izumiyama Hiroaki , Yamakoshi Takao , Takahashi Yuya , Nishiguchi Yuki , Okuyama Ryosuke
Published: August 2023

In Japan, many debris flows and sediment-laden floods cause serious damage to human life and property. Effective measures require high-accuracy reproduction and prediction of runout distance (bed variation reach) via numerical simulations. One possible method to increase the accuracy of numerical simulation results involves reviewing the methods used to evaluate depositing rate for flows that contain many different sizes of sediments. This study performed experiments using an artificial channel and high-speed cameras to identify parameters that govern depositing rate. The channel implemented exhibited a change in slope point; thus, the slope of the upper reach differed from the slope of the lower reach. The experiments showed that the equation representing depositing rate is closely related to flow velocity. Additionally, the equation of depositing rate can be determined if other parameters are consistently considered.
Numerical Simulation Reflecting Buildings in Area Damaged by Debris flow
Authors: Kang Bae-Dong , Jun Kye-Won , Lee Ho-Jin , Jang Chang-Deok , Jo Hang-Il
Published: August 2023

More than 80% of average annual precipitation in South Korea occurs between June and September owing to heavy rainfall and typhoons in summer, and its land is vulnerable to mountain disasters (landslides and debris flow) as 63% of it is mountainous areas. In this study, an area damaged by debris flow in Wondeok-eup, Samcheok-si, Gangwon-do, Korea under the influence of Typhoon Mitag in 2019 was surveyed and numerical modeling was performed. Topographic data were created using the 5m grid DEM derived through the field survey data and GIS technique as well as the building data of the damaged area, and debris flow modeling was performed using the Hyper KANAKO model. A comparison with the inundation trace map showed that the simulation results based on topographic data that reflected buildings exhibited similar flow patterns and characteristics to the actual damage.
Keynote lecture. Debris-flow detection for early warning purposes: Recent advances, open problems, and future challenges
Authors: Coviello Velio
Published: August 2023

The mitigation of risk caused by debris flows is increasingly pursued by means of non-structural measures, including early warning systems (EWSs). Nowadays, EWSs are becoming attractive thanks to their flexibility and due to the new paradigm of smart sensor networks, proposed as a tool to monitor and gather intelligence from the surrounding environment. Also, an increasing number of extreme meteorological events is expected due to climatic changes, resulting in a consequent growing risk in areas considered safe so far. Although the technological development of detection systems based on low-cost sensor networks has recently spurred a great deal of interest, very few success stories exist of EWSs operational for long periods and trusted by local authorities. In this work, I present an overview on the recent advances, open problems, and future challenges in the field of detection of debris flows for early warning purposes, with a special attention to the European Alps. I discuss (i) the uncertainties related to the use of rainfall thresholds and their possible improvement based on field observations in the source areas, (ii) the new opportunities that seismo-acoustic sensors open in terms of warning performances and lead time, (iii) the problematic interaction of EWSs with structural mitigation measures, and (iv) the old but still actual problem of responsibility in issuing an alarm. Finally, I debate the “information paradox” that can contribute limiting the adoption of EWSs in future and the possible benefits of communication and dissemination.
What does landslide triggering rainfall mean?
Authors: Guthrie Richard , Wasklewicz Thad , Knibbs Graham , Hertzman Eric , Imen Sanaz , Bigelow David
Published: August 2023

Landslide-triggering rainfall thresholds are often subject to both false negatives (landslides where none are expected) and false positives (no landslides despite thresholds being exceeded). Debris flows and shallow landslides impact communities and infrastructures worldwide. Refinement of the relation between rainfall intensity and landslide occurrence would help remove the imprecise nature of this tool moving forward. Continuous 6-hour gridded precipitation data from over a five-year interval 900 km2, combined with a complete, time-constrained, landslide data base over the same period, are used to derive relations for the probability of shallow landslides with rainfall intensity measured over 6-hour, 12-hour, or 24-hour durations. Previously published and widely used thresholds are quantified in terms of landslide probability per unit area and demonstrate, for different sized study areas, the likelihood that at least one landslide will be initiated at different intensities and durations. Probabilistic distribution of landslides for a given study area and rainfall intensity can be easily derived using the binomial method from these relations.
Monitoring debris flows in the Gadria catchment (eastern Italian Alps): Data and insights acquired from 2018 to 2020
Authors: Marchi Lorenzo , Coviello Velio , Cavalli Marco , Comiti Francesco , Crema Stefano , Macconi Pierpaolo
Published: August 2023

This work analyses seven debris flows recorded between 2018 and 2020 in the Gadria instrumented catchment (South Tirol). We focus on three aspects not previously explored in this catchment: (i) the debris-flow transfer times between the headwaters and the outlet; (ii) the longitudinal variability of debris-flow velocity between the three downstream monitored cross-sections, and (iii) the characteristics of the secondary surges observed in three debris flows. In most cases, the mean velocity of the debris flow estimated from the upper to the lower channel reaches (for travel distance of 2155 m) is rather low, ranging between 1.9 and 3.9 m/s. This result could indicate a progressive slowing down, and possibly even temporary stops of debris flows along the path. Some variability in flow velocity was observed between two channel reaches in the lower part of the catchment (0.7 – 2.3 m/s in the upstream reach, and 1.4 – 4.7 in the downstream one). Regarding the secondary surges, these have been noted to occur superimposed on slow-moving slurry-type phases. The mean velocity of the secondary surges varied between 3.5 and 8.9 m/s, with an average value close to 6 m/s for all three events. Their regular shape, duration, and depth suggest that such surges were generated by flow instabilities, with no external forcing.
Real-time debris flow detection using deep convolutional neural network and Jetson Nano
Authors: Pham Minh-Vuong , Song Chang-Ho , Nguyen Thanh-Nhan , Lee Ji-Sung , Kim Yun-Tae
Published: August 2023

This study aims to develop a potential system for real-time detection of debris flow motion using a deep convolutional neural network (CNN) and image processing techniques. A system consisting of a pre-trained CNN model, NVIDIA Jetson Nano, and a camera was used to identify debris flow movement. The pre-trained CNN model was trained on an image dataset derived from 12 debris flow videos obtained from small flume tests, large flume tests, and several debris flow events. The application results of the proposed system on the flume test in the laboratory reached an F1 score of 72.6 to 100%. The real-time processing speed of the CNN model achieved from 2 to 21 frames per second (FPS) on the Jetson Nano. Both the accuracy and the processing speed of CNN model depend on the size of the video input and the input size of the model CNN. The CNN model of 320 × 320 pixels with a resolution of 800 × 480 pixels gives accuracy (F1 = 99.2%) and processing speed (FPS = 20) considered the optimal model when running the Jetson Nano device; thus, it can be applied for early detection and warning systems.
Landslide Analysis combining Laser Scanning and Photogrammetry
Authors: Pinto Pedro , Barros Juliana , Pinheiro Marisa , Tomás Roberto , Miranda Tiago , Pereira Eduardo
Published: August 2023

After a sequence of weeks of heavy raining, a catastrophic mass movement occurred in the parish of Palmeira de Faro, Esposende (N Portugal) on November 23, 2022. The collapsed slope presented a maximum height of about 21 m and a length of 45 m. In order to document and analyse this case from the geotechnical perspective, a general survey was devised including the use of aerial photography, laser scanning and conventional topographic survey methods. The results obtained showed that these techniques provide very accurate and abundant information that is essential to support a comprehensive documentation of the features and variables of the slope. The mechanisms involved in this catastrophic collapse are still under investigation, and causes such as the excessive rainfall in the previous months or geologic conditions are still being considered, although currently the existing information seems to indicate for a combination of debris flow / rock slide driven event.
Bedrock Erosion by Debris Flows at Chalk Cliffs, Colorado, USA: Implications for Bedrock Channel Evolution
Authors: Rengers Francis , Kean Jason , Coe Jeffrey , Hanson Megan , Smith Joel
Published: August 2023

Debris flow erosion into bedrock helps to set the pace of mountain denudation, but there are few empirical observations of this process. We studied the effects of debris flows on bedrock erosion using Structure-From-Motion photogrammetry and multiple real-time monitoring measurements. We found that the distribution of bedrock erosion across the channel cross-section could be generalized as an exponentially decreasing function of height above the channel thalweg. Using this empirical function, we simulated the erosion at a cross-section after the theoretical passage of a migrating knickpoint effectively matching the upstream pre-knickpoint cross-sectional shape to the downstream post-knickpoint cross-sectional shape via debris-flow bedrock erosion.
Photogrammetrically UAV based terrain data generation and automatic extraction of torrential properties
Authors: Schmucki Gregor Rafael , Bartelt Perry , Bühler Yves , Caviezel Andrin , Graf Christoph , Marty Mauro , Stoffel Andreas , Huggel Christian
Published: August 2023

Debris flows are a severe hazard in mountainous regions. However, cost-effective long-term studies of debris flows are seldom, which leads to substantial uncertainties in hazard mitigation methods. This paper investigates whether cost-effective remote sensing techniques can be applied to assess the hazards of mountain torrents and to gather accurate long-term information on the development of the watershed. Torrents that are prone to debris flows are often devoid of vegetation and can thus be well surveyed using photogrammetric methods based on uncrewed aerial vehicle (UAV) surveys. The possibility of extracting automatically torrent parameters from high-resolution terrain models, such as cross-sectional area or slope, is explored. The presented methodology yields continuous and automatically derived parameters along the torrent, which is a major advantage over pointwise field surveys. Cross-validation with field measurements reveals a strong agreement. These parameters are very accurate along highly incised sections, while they are severely limited along sections with steep adjacent hillslopes and/or dense vegetation. We show that these kinds of assessments greatly gain from UAV data followed by automatic parameter extraction. The extracted parameters provide insights so that key sections and weak points can be identified and accurately assessed in the field. We find that UAV data can contribute to a comprehensive, reproducible and objective assessment of torrent processes and predispositions. However, ground-based fieldwork is still essential and further research on remote sensing-based hazard assessment of torrents prone to debris flows is crucial.
The RES approach for debris flow susceptibility analysis: A case study
Authors: Taboni Battista , Vianello Davide , Vagnon Federico , Ferrero Anna Maria , Bonetto Sabrina Maria Rita
Published: August 2023

Climate change has increased the occurrence and magnitude of debris flow events, especially in mountain areas. Moreover, their unpredictability requires to develop reliable methodologies for the evaluation of debris flow susceptibility, which is the starting point for risk assessment and management. In this paper, a modified version of the Debris flow Propensity Index (DfPI) is developed for the debris flow susceptibility estimation at basin scale. Bedrock lithology, fracture network, quaternary deposits, slope angle, channel network, and land use were identified as debris flow predisposing factors and were indexed by using open-access data and geodatabases. The objective of the proposed study is to develop a simple and economic procedure for the susceptibility estimation, easily to implement in GIS-based software for further analyses, such as propagation simulations or hazard scenarios, useful for planning mitigation strategies. The Can? Valley, a small valley located in the more famous Camonica Valley, (Lombardia Region, Northern Italy), was used as a case study for developing and testing the proposed approach.
Detection of debris-flow events from seismic signals using Benford’s law
Authors: Zhou Qi , Tang Hui , Turowski Jens M. , Braun Jean , Yang Ci-Jian , Dietze Michael , Lagarde Sophie , Abdelwahab Ahmed , Walter Fabian
Published: August 2023

The first step in building an early warning system using seismic signals is to automatically identify events of interest. Here, the first digit distribution of seismic signals generated by debris flows and other surface processes was calculated to validate compliance with Benford's law (BL). A detector model for debris flow events was introduced based on amplitude range and goodness of fit of BL. We show that seismic signals generated by debris flows, landslides, and bedload transport follow the BL. These events release more energy and last longer than rockfalls, which do not follow BL. In the test dataset with 1224 samples, the accuracy of the detector model in identifying debris flow events was 0.75.
Keynote lecture. Forecasting the inundation of postfire debris flows
Authors: Barnhart Katherine R. , Jones Ryan P. , George David L. , Rengers Francis K. , Kean Jason W.
Published: August 2023

In the semi-arid regions of the western United States, postfire debris flows are typically runoff generated. The U.S. Geological Survey has been studying the mechanisms of postfire debris-flow initiation for multiple decades to generate operational models for forecasting the timing, location, and magnitude of postfire debris flows. Here we discuss challenges and progress for extending operational capabilities to include modeling postfire debris-flow inundation extent. Analysis of volume and impacted area scaling relationships indicated that postfire debris flows do not conform to assumptions of geometric self-similarity. We documented sensitivity of impacted areas to rainfall intensity using a candidate methodology for generating inundation hazard assessments. Our results emphasize the importance of direct measurements of debris-flow volume, inundated area, and high temporal resolution rainfall intensity.
The spatial distribution of debris flows in relation to observed rainfall anomalies: Insights from the Dolan Fire, California
Authors: Cavagnaro David B. , McCoy Scott W. , Thomas Matthew A. , Kostelnik Jaime , Lindsay Donald N.
Published: August 2023

A range of hydrologic responses can be observed in steep, recently burned terrain, which makes predicting the spatial distribution of large debris flows challenging. Studies from rainfall-induced landslides in unburned areas show evidence of hydroclimatic tuning of landslide triggering, such that the spatial distribution of events is best predicted by the observed rainfall anomaly relative to climatic norms rather than by absolute rainfall. In this paper, we test whether the spatial distribution of debris flows in response to rainfall can be similarly predicted by rainfall anomaly. The 520 km2 Dolan Fire burn scar in Monterey County, California, USA, spans a sharp hydroclimatic gradient and experienced a widespread storm in January 2021 that triggered floods and debris flows, providing a natural experiment in which to test this hypothesis. In this study, we use remote and field methods to map debris-flow response and examine its spatial heterogeneity. Together with rainfall data, our mapping reveals that the observed anomalies in peak 15-min rainfall intensity (I15) relative to the intensity of the 1-yr return interval storm predict debris-flow occurrence better than the absolute peak I15. Our findings indicate that debris-flow processes and threshold rainfall required for debris-flow initiation may be tuned to local hydroclimate.
Rainfall-induced shallow landslides triggered after vegetation removed because of fires: G-XSLIP application to Gioiosa Marea (Sicily, Italy)
Authors: Gatto Michele Placido Antonio , Lentini Valentina , Montrasio Lorella , Castelli Francesco
Published: August 2023

The paper analyses how vegetation prevents the triggering of rainfall-induced shallow landslides by using the G-XSLIP platform, which is based on G-SLIP model, i.e., the SLIP model updated with vegetation parameters for root reinforcement and rain interception due to canopy. G-XSLIP is applied to an area in Gioiosa Marea (Sicily, Italy), where on 9th September 2016 shallow landslides occurred, depositing on the state road SS 113. The analyses demonstrate that the triggering of these phenomena is related to the removal of vegetation after summer fires some months before, which decreases computed safety factors by about half.
Projected Effects of Climate Change on Post Wildfire Debris-Flow Hazards Applied to the 2017 Thomas Fire, California USA
Authors: White Zane , Santi Paul
Published: August 2023

Climate changes are expected to increase the likelihood, volume, and overall hazard of post-wildfire debris flows, but it is a challenge to estimate specific changes and impacts from these hazards. In this study we use climate change models to modify the parameters in predictive equations to demonstrate changes for the 2017 Thomas Fire in California USA if a similar event were to occur in the years 2050 or 2075. Our results show that, based on changes in fire size, the number of burned drainage basins in 2050 would increase by 105% and by 2075 they would increase by 147%. Based on changes in fire size and rainfall effects, the overall volume of debris produced by debris flows would increase by 96% in 2050 and 147% in 2075. Finally, there would be a notable shift in hazard level towards basins classified as high hazard. The hazard models for the 2017 fire classified 54% of the drainage basins (937 total) as high hazard, but by 2050 there would be 60% (1869 total) classified as high hazard. By 2075, 67% of basins would be high hazard (2385 total). This represents an increase in high hazard drainage basins of 99% by 2050 and 155% by 2075. The results of this exercise indicate a substantial future increase in area impacted by post wildfire debris flows, the amount of debris produced, and the level of hazard posed.
Debris flow hazard assessment: Laboratory experiences and numerical modelling
Authors: Castelli Francesco , Lentini Valentina , Venti Alessandra Di
Published: August 2023

In the last years, the study of debris flow has become very important in the research activity and in the engineering practice. The use of numerical models is able for the study of debris flow’s propagation. The study area is located in the north-east Sicilian coast and in particular in the municipality of Gioiosa Marea, severely affected by landslides occurred from 2000 to 2013. In this case study, the FLO-2D code has been used. The soil parameters has been determined by means of in situ investigations and laboratory tests. The knowledge of the physical and mechanical properties is very important to define the input parameters of the model, including the volumetric concentration associated with the soil friction angle.
Constraining post-fire debris-flow volumes in the southwestern United States
Authors: Gorr Alexander , McGuire Luke , Youberg Ann
Published: August 2023

Debris flows pose a serious threat to human life and infrastructure in downstream areas following wildfire. This underscores the necessity for having a hazard assessment framework in place that can be used to estimate the impacts of post-wildfire debris flows. Current hazard assessments in the western United States (USA) use empirical models to assess the volume of potential post-wildfire debris flows. Volume models provide information regarding the magnitude and potential downstream impacts of debris flows. In this study, we gathered post-wildfire debris-flow volume data from 54 watersheds across the states of Arizona (AZ) and New Mexico (NM), USA, and compared these data to the output of a widely used empirical post-wildfire debris-flow volume model. Results show that the volume model, which was developed using data from the Transverse Ranges of southern California (CA), tends to overestimate observed volumes from AZ and NM, sometimes by several orders of magnitude. This disparity may be explained by regional differences between southern CA and AZ and NM, including differences in sediment supply. However, we found a power- law relationship between debris-flow volume and watershed area that can be used to put first-order constraints on debris-flow volume in AZ and NM.
A novel downstream Flood Hazard Grade Index incorporating upstream Hydrograph Characteristics to predict Debris Flow Runoff
Authors: Harada Norio , Nakatani Kana , Fujimoto Masamitsu , Satofuka Yoshifumi
Published: August 2023

The July 2020 debris flow in Japan caused enormous damage, and briefing sessions on disaster prevention have prompted demands for detailed explanations and predictions of such phenomena in high-risk areas. It is necessary to obtain four-dimensional risk information, which considers temporal changes in disaster risk, rather than limiting the analysis to conventionally static information. In this study, we developed a method for setting the boundary conditions necessary for debris flow prediction via a four-dimensional hazard map using various types of digital information. To understand the effects of hydrograph characteristics from the upstream, flow discharge was analysed under different flow conditions, such as topography-driven riverbed shear stress, using a one-dimensional numerical model that considers water and sediment flow. Our results suggested that characteristics of the upstream inflow hydrograph affect flood runoff processes downstream; therefore, we developed a separate downstream flood hazard grade index that uses characteristics of the upstream inflow hydrograph as input.
The Emerging Widespread Debris Flow Disasters in Tropical Terrain of Peninsular Malaysia: Understanding the Risk and Policy Intervention
Authors: Jaapar Abd Rasid , Md Aripin Mohamad Faruq Syahmi , Komoo Ibrahim , Ali Che Aziz , Ramli Zamri , Harun Abd Rahim , Bachat James , Mohamad Zakaria , Omar Rohayu Che , Razak Khamarrul Azahari , Lim Choun Sian
Published: August 2023

Several widespread debris flow disasters stroke Peninsular Malaysia in between 2021 and 2022, scattered across the country. It was the first time for this hazard being nationally recognised as a type of geological disaster in the country. Debris flow disaster is not a new phenomenon. It had been recorded since 1995, however, in the past they were isolated incidents and did not attract much attention. The recent widespread debris flow disasters started in Gunung Jerai, Kedah on 18 August 2021; followed by similar incidents but in 3 different states concurrently in (1) Bentong, Pahang, (2) Hulu Langat, Selangor, and (3) Jelebu, Negeri Sembilan on 18 December 2021; Kenyir, Terengganu on 27 February 2022; and finally at Gunung Inas, Kedah on 4 July 2022. These disasters sparked numerous technical and social issues where heated debates on whether they were purely due to natural processes or caused anthropogenic activities. Previously, debris flow phenomena in Malaysia were so rare, that the term ‘debris flow’ was not familiar to the lay public. The term of “debris flow” was often disregard or used interchangeable with ‘water surge’ phenomena by the media and public, especially for sudden sediment water surge from hilly upstream after intense rainfall at hillside river catchment areas, normally occurs during the monsoon season. The ordinary water surge has significantly lesser level of destruction and momentum as compared to a debris flow with higher debris-type sediments. This paper discusses the emerging issues of debris flow in Malaysia and some initiatives being carried out in in facing the geohazard. The Department of Mineral and Geoscience Malaysia and a team of local geohazard experts have taken the lead to carry out studies to understand the sudden emergence of widespread and cascading debris flow events in Malaysia. As a result, proposal on policy intervention was put forward to the relevant government ministries; post-disaster programme has been continuously carried out to educate the communities on the geological disaster risks through community-based disaster risk management (CBDRM).
Impact of climate change on hydro-meteorological trigger conditions for debris flows in Austria
Authors: Kaitna Roland , Prenner David , Switanek Matt , Stoffel Markus , Maraun Douglas , Hrachowitz Markus
Published: August 2023

Debris-flow activity is expected to change in a future climate. In this study we connect a susceptibility model for debris-flows on a regional scale with climate projections until 2100. We use this to assess changes of hydro-meteorological trigger conditions for debris flows in six regions in the Austrian Alps. We find limited changes on an annual basis, but distinct changes when separating between hydro-meteorological trigger types and regions. While regions in the east and in the south of Austria may experience less days susceptible to debris flows in summer, there is a general trend of increasing susceptibility earlier in the year for both, rainfall-related and snow-related trigger conditions. The outcomes of this study serve as a basis for the development of adaption strategies for future risk management from this debris-flow hazard.
Integration of meteorology and geomorphology for enhanced understanding of post-fire debris-flow hazards
Authors: Oakley Nina , McGuire Luke , Lancaster Jeremy
Published: August 2023

Through precipitation, the fields of meteorology and geomorphology are fundamentally linked, thus interdisciplinary efforts are needed to advance understanding and warning of rainfall-driven geohazards. With a focus on recent efforts specific to post-fire debris flows in California, our presentation provides an overview of the benefits and challenges of working in an interdisciplinary team of meteorologists and geomorphologists, as well as results of a recent project demonstrating advancement through the integration of these fields. In this project, we combine high-resolution ensemble precipitation forecasts with post-fire debris-flow models to explore the feasibility and potential value of providing probabilistic post-fire debris-flow hazard information over a burn scar. In sharing these examples, we emphasize the multi-benefit nature of these efforts, and encourage future interdisciplinary efforts that improve warning and mitigation of rainfall-driven geohazards.
Modeling the runout behavior of the July 23rd, 2015 Cancia debris-flow event using two numerical models
Authors: Qiao Zhitian , Berti Matteo , Shen Wei , Li Tonglu
Published: August 2023

On 23 July 2015, a typical volume-enlarging debris flow was triggered by heavy rainfall that occurred a few days before the event. The available data corresponding to this event is obtained from detailed field investigations conducted before and after the event, as well as the monitoring station installed in June 2014. This study aims to reproduce the July 23 debris-flow event using two different numerical methods, analyse the influence of entrainment on the runout behavior of the debris flow and compare the performance of different numerical methods when simulating the same debris-flow event. The results showed the following: (1) The expanded inundated area and unrealistic overflowing were observed in the scenario without entrainment while the simulation that takes entrainment into account presented more perfect results. It illustrates that entrainment is a non-negligible factor for the simulation of these volume-enlarging debris flows. (2) Two models considering the entrainment performed a good match between the simulation and the field survey. However, some noticeable differences can be observed in terms of the erosion-deposition distribution because different numerical schemes were adopted in the two models. Specifically, the DAN3D code always gives higher mobility and larger lateral spreading relative to the Shen model.
Satellite-based monitoring of an open-pit mining site using Sentinel-1 advanced radar interferometry: A case study of the December 21, 2020, landslide in Toledo City, Philippines
Authors: Ramirez Ryan , Abdullah Rajiv Eldon , Jang Woojae , Choi Shin-Kyu , Kwon Tae-Hyuk
Published: August 2023

Understanding the causal factors and mechanisms behind catastrophic landslides and debris flows is crucial for accurate forecasting and disaster risk reduction. Synthetic aperture radar (SAR) data and interferometric SAR (InSAR) technologies provide valuable information for early warning systems’ landslide and debris flow detection and monitoring strategies. This paper applied the Sentinel-1 Persistent Scatterer InSAR (PSInSAR) technique to detect and monitor precursory slope movements over the open-pit mining site in Toledo City, Cebu Island, in the Philippines. The results show that the slope showed instabilities between December 30, 2019, to December 12, 2020, before the actual failure on December 21, 2020. The landslide initiation zone moved with velocities exceeding –10 mm/yr and reaching –90 mm/yr. The topography and morphology of the mining site contributed to the cut slope instabilities. The mining operations and hydrometeorological conditions during the analysis period aggravated the situation, leading to the cut slope failure. Overall, with favorable slope geometry, surface characteristics, and SAR data availability, the Sentinel-1 PSInSAR technique can serve as a landslide early warning system tool and aid decision-making in an actively operating open-pit mine and other landscapes.
Using integrated growth to delineate debris-flow inundation
Authors: Reid Mark E. , Brien Dianne L. , Cronkite-Ratcliff Collin , Perkins Jonathan P.
Published: August 2023

Debris-flow volume is fundamental to mobility, yet many debris flows change volume as they travel. Growth can occur through diverse processes such as channel-bed entrainment, bank failures, aggregation of landslides, and coalescence of multiple flows. Integrating growth, either over upslope area or stream length, combines the effects of these growth processes and requires specification of only the growth zone extent and a growth factor. To delineate potential debris-flow inundation, we implement integrated growth factors and simple volume-area relations in a new USGS software package, Grfin Tools. We present two examples of forecasting debris-flow inundation – one using an area growth factor in Puerto Rico and another using a channel-length growth factor in Oregon, USA. The use of growth zones and growth factors enables scenario-based hazard assessments for geomorphic settings with debris-flow growth.
Rockfalls change the runout and frequency of debris flows at Punta Nera (Eastern Italian Alps)
Authors: Simoni Alessandro , Barbini Matteo , Battistel Leonardo , Bernard Martino , Berti Matteo , Cargnel Osvaldo , Ciuffi Pier Paolo , Gregoretti Carlo
Published: August 2023

In the Dolomitic region, many debris flow basins have headwaters characterized by extremely steep slopes of bare outcropping rock. Cliffs are commonly incised by multiple chutes which rapidly deliver runoff at their base where the channels incise scree deposits. Debris flows mobilize and transport sediment along such ephemeral channels following intense summer convective rainstorms. In the debris flow basin of Punta Nera, a series of rockfalls, which occurred in the upper part of the headwater between 2013 and 2016, caused dramatic changes in the debris flow dynamics. Starting from the summer of 2014, the runout of debris flow events increased so much that it reached the national road, which runs at the toe of the debris flow fan, attracting media attention and prompting the adoption of protective measures. Here, we use newspaper reports, direct observations, aerial and terrestrial photograph, monitoring data and topographic surveys to document the rockfalls and the debris flow activity. The sudden increase in sediment availability changed the magnitude of events, their runout and the critical conditions for debris-flow occurrence.
Probabilistic Prediction Method of Erosion Volume and Deposition Area from Rainfall Observation Data
Authors: Yamanoi Kazuki , Shikakura Kaori , Kawaike Kenji , Oishi Satoru
Published: August 2023

We propose a methodology to estimate the spatial distribution of the probability of sediment deposition due to debris flow from rainfall data by combining the probability prediction of erosion volume based on an ordinal logistic regression and a sediment transport simulation. By using the Receiver Operating Characteristic (ROC) curve and Area Under Curve (AUC) we have selected the best combination of shortand long-term rainfall indices used as explanatory variables in the ordinal logistic model. The results showed that the regression model using 60-minute and 48-hour rainfall indices performed well and that the regression model using three events improved the predictability of local disasters in 2014. Furthermore, we performed Monte Carlo debris-flow simulations using rainfall data from 2014 using the model. We confirmed that the spatial distribution of disaster probability is consistent with the actual damage.
Design of two retention basins along the torrent Liera on the Gares Valley (Dolomites, North East Italy) after the storm Vaia
Authors: Barbini Matteo , Bernard Martino , Boregggio Mauro , Da Re Fabio , Gregoretti Carlo
Published: August 2023

A storm called “Vaia” affected the North East Italy and South West of Austria at the end of October 2018. On the Gares Valley (Canale d’Agordo, North East Italian Alps), the abundant runoff triggered several in-channel debris flows that transported hundreds of thousands of cubic meters of sediments on the valley bottom. Some control works for retaining the sediment volume have then been built in the most threatened sites. Herein we show the design of two retention basins that should protect both the Liera torrent and the main road parallel to it. We computed the debris-flow volume to be retained both using an empirical law and simulated solid-liquid hydrographs corresponding to a return period of 300 years. The estimate of the debris-flow volume in the empirical law depends on the basin area upstream of the deposition zone, whereas, in the solid-liquid hydrographs, it depends on the area of the basin closed at the initiation area, as well as on the design rainfall.
Propose of Design Method on Level II load of open Sabo dam
Authors: Horiguchi Toshiyuki , Katsuki Satoshi , Komatsu Yoshiharu
Published: August 2023

This study presents a load model of the Level II design for a steel pipe open Sabo dam. The Level II design is associated with a lower occurrence frequency than the conventional design concept, to the performance of debris flow trapping efficacy against higher discharge caused by heavy precipitation in recent years. A dynamic load model reveals experimental observations, and static models similar to the conventional design load models are evaluated from the viewpoint of a rational load. Dynamic and elastoplastic analyses are conducted for one structure, and three types of basin area models utilized Level II load models using a dynamic load. The safety evaluation results confirm that the design load models are composed of each other.
Multiple debris-resisting barriers with basal clearance: A study on impact force
Authors: Liu Haiming , Choi Clarence E. , Ng Charles W. W.
Published: August 2023

Optimising debris-resisting barriers is of paramount importance on constructing cost-effective and eco-friendly mitigation works. Multiple barriers with basal clearance can potentially serve as an optimal approach because they can facilitate flow energy dissipation, reduce the impact force on each barrier, ease the maintenance and resist a large flow volume. However, the design impact force of multiple barriers with basal clearance remains empirical. In this study, physical model tests were carried out to investigate the impact force of idealised dry granular flow against dual rigid barriers with basal clearance using a 5-m-long flume model. Measured impact forces show that basal clearance attenuates the impact force exerted on the second barrier by apportioning the impact forces from basal discharge and overflow. Basal discharge dissipates the kinetic energy of landing flow and reduces the impact force of overflow. A rational design of basal clearance serves as an efficient measure for optimising the design of multiple barriers.
Static and dynamic impact forces on a rigid barrier due to dry debris flow simulated by a DEM-based granular column collapse
Authors: Ujjwal Aman , Sureka S. , Mishra Govind Kant , Mukherjee Mousumi , Dey Arindam
Published: August 2023

Geophysical flows like debris flows require protective barriers so as to scale down their disastrous effects. The impact force exerted on these barriers depends upon several factors like the velocity and height of flowing debris, the density and other associated characteristics of flowing mass, and the height of the sediment deposited behind the barrier. These factors are found to vary with time during the debris flow process, thereby causing significant temporal variations in the magnitude of impact force. Assessing the impact force on a barrier is a prerequisite for its design. In this work, the impact of dry debris flow, emanating from a granular column collapse, on a rigid barrier has been investigated using 3-D Discrete Element Method (DEM). It has been found that the impact force is predominantly influenced by dynamic thrust at the initial stages, which, with elapse time, subsequently transits to the sole contribution of static pressure. The applicability of the existing hydraulic models comprising hydrostatic and hydrodynamic formulae has also been analysed in this exercise. Furthermore, the empirical coefficients associated with these formulae have been evaluated for the dry debris flow impacting the rigid barrier.
Tensile stress development and critical behavior of a flexible barrier
Authors: Huo Miao , Huang Fucheng , Yang Maojun , Jiang Chenjie
Published: August 2023

A DEM numerical approach is employed to illustrate the critical stress development of a three-supporting cable flexible barrier under a large scale stony debris movement impact. A proper linear parallel bond is applied to build the flexible barrier model. Critical state is presented by lowering the tensile resistance of the flexible barrier and steepening the channel slope. The tensile stress of the supporting cables is primarily studied. Results mainly indicate that the particle-structure contact is essential to the stress development. The bottom cable always exhibits larger tensile stress due to the massive collision and compressive force of particles and the tensile force exerted by the vertical cable-net joint system. On the other hand, the intermediate cable receives lower collision and compressive force, resulting in smaller tensile stress. The bottom cable indicating numerous direct particle-structure contact part performs brittle failure, which is analogous to the concentrated load feedbacks. The loading of the intermediate one reaches ductile failure, reflecting the desirable effect of dispersing loads. This study suggests that practical engineering should try to avoid massive boulder impact or reinforce the bottom cable in order to improve the hazard prevention design.
Keynote lecture. Defining Protection Works Against Debris-Flow Hazards: Industrial Standard, Tailor-made or Haute-couture?
Authors: Piton Guillaume
Published: August 2023

Despite centuries of forestry and empirical soil conservation works as well as decades of research on debris flow processes, defining protection strategies against debris flows remains complicated. We are far from guidelines resembling an industrial standard to define the type, location and shape of debris flow protection works. We believe that this particular step will likely never be fully standardized because design engineers must have a certain degree of freedom to tailor the protection works to the astonishing varieties of catchments, geologies and geomorphologies, and the associated complex emerging debris flow regimes. Some catchments are have such specific features that defining an adapted protection strategy requires innovation: this is not even “tailor-made” but perhaps “haute-couture”. In this paper and the associated keynote lecture, we propose a possible way to approach the problem by firstly focusing on the sediment transport connectivity and the channel malfunctions leading to debris flow deposition; and secondly to select structures that prevent the latter, as well as to adjust the channel capacity to the debris flow supply.
Sustainable tourism through architectural hybridization
Authors: Zouaghi Samia , Salami Younes
Published: August 2023

In this paper, hybridization is proposed as an alternative approach to sustainable tourism development in Morocco’s southeastern cities. Hybridization refers to the integration of multiple elements, such as traditional and modern, to create a new synthesis that incorporates the aspects required from a modern building. The evolutionary approach adopted helps to balance between short-term requirements and long-term sustainability, while also preserving cultural heritage and promoting innovation. By implementing sustainable and culturally sensitive strategies, a positive future can be secured for architectural and urban systems like Ksours and Kasbahs.
Assessment of residential settlement planning in Medina, based on climate adaptability
Authors: Benzarti ep Ghedas Habiba , Abdelmajid Jemni , Coloma Pico Eloi
Published: August 2023

The theme of World Habitat Day 2020 was Housing for All: “A Better Urban Future”. In light of this postulate, this study aims to determine the climate response of traditional urban morphology to the Sousse climate, which allows us to assess the effectiveness of ancient urban planning considered a model of low-energy and low-carbon. This study purposes to help future urban planners in the early phase of the project and preserve their urban heritage. Design strategies such as indoor and outdoor daylighting and different natural ventilation conditions were studied to assess ancient city planning. The results show that the grouped houses in linear blocks with courtyards promote natural ventilation, solar gain, and thermal comfort control. This self-contained, compact urban morphology is beneficial in the semi-arid climate; it reduces heat loss through the exterior envelope and creates a comfortable atmosphere inside and outside the block, especially in summer.