Comparison of Methods and Procedures for Debris-Flow Volume Estimation

2014 ◽  
pp. 115-119 ◽  
Author(s):  
M. Arattano ◽  
G. Bertoldi ◽  
M. Cavalli ◽  
F. Comiti ◽  
V. D’Agostino ◽  
...  
Keyword(s):  
Debris Flow ◽  
Volume Estimation ◽  
Comparison Of Methods ◽  
Flow Volume

scholarly journals Debris-flow volume quantile prediction from catchment morphometry

2020 ◽  
Author(s):  
Alexander Densmore ◽  
Tjalling de Haas
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Catchment Area ◽  
Volume Estimation ◽  
Flow Volume ◽  
Catchment Characteristics ◽  
Elevation Data ◽  
Watershed Boundary ◽  
Catchment Morphometry ◽  
Frequency Curves

<p>Estimation of the volumes of potential future debris flows is key for hazard assessment and mitigation. Worldwide, however, there are few catchments for which detailed volume-frequency information is available. We (1) reconstruct volume-frequency curves for 10 debris-flow catchments in Saline Valley, California, USA, from a large number of well-preserved, unmodified surficial flow deposits, and (2) assess the correlations between lobe-volume quantiles and a set of morphometric catchment characteristics. We find statistically-significant correlations between lobe-volume quantiles, including median and maximum, and catchment relief, length (planimetric distance from the fan apex to the most distant point along the watershed boundary), perimeter, and Melton ratio (relief divided by the square root of catchment area). These findings show that it may be possible to roughly estimate debris-flow lobe-volume quantiles from basic catchment characteristics that can be obtained from globally-available elevation data. This may assist with design-volume estimation in debris-flow catchments where past flow volumes are otherwise unknown.</p>

Spatio-temporal patterns of debris-flow erosion and deposition in the Illgraben torrent

2020 ◽  
Author(s):  
Tjalling de Haas ◽  
Wiebe Nijland ◽  
Brian McArdell
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Temporal Patterns ◽  
Volume Estimation ◽  
Swiss Alps ◽  
Flow Volume ◽  
Flow Measurements ◽  
Erosion And Deposition ◽  
Deposition Patterns ◽  
Spatio Temporal

<p>Debris flows can grow greatly in size and hazardous potential by eroding bed material, but effective hazard assessment and mitigation is currently hampered by limited understanding of erosion and deposition dynamics. We have collected high-resolution pre- and post-flow topography with drone-based photogrammetry in the Illgraben channel in the Swiss Alps. We present erosion and deposition patterns as a result of six debris flows and intensive subcatchment activity over a 3.3 km long unconsolidated reach with check dams, and interpret these erosion and deposition patterns with in-situ flow measurements. We show that the spatio-temporal patterns of erosion and deposition in natural debris-flow torrents are highly variable and dynamic. We identify a memory effect where erosion is strong at locations of strong deposition during previous flows and vice versa. Large sediment inputs from subcatchments initially result in new channel erosion through the subcatchments deposits and at the same time upstream deposition as a result of backwater effects. It is generally believed that erosion increases with debris-flow magnitude, but we show that there is a limit to debris-flow bulking set by channel geometry. Large flows that overtop their channel deposit large amount of sediment in levees and on overbanks, leading to net deposition despite strong thalweg erosion, and thus a decrease in flow volume. These findings provide key guidelines for flow volume forecasting, emphasizing the importance of memory effects and the need to resolve both erosion and deposition for accurate flow volume estimation.</p>

scholarly journals A probabilistic approach to post-wildfire debris-flow volume modeling

Landslides ◽  
2017 ◽  
Vol 14 (4) ◽  
pp. 1345-1360 ◽  
Author(s):  
Ian P. Donovan ◽  
Paul M. Santi
Keyword(s):  
Debris Flow ◽  
Probabilistic Approach ◽  
Flow Volume ◽  
Volume Modeling

Deciphering the seismic and normal-force fluctuation signatures of debris flows: an experimental assessment of the effects of flow composition and dynamics

2021 ◽  
Author(s):  
Tjalling de Haas ◽  
Amanda Aaberg ◽  
Fabian Walter ◽  
Zhen Zhang
Keyword(s):  
Debris Flow ◽  
Size Distribution ◽  
Debris Flows ◽  
Large Particle ◽  
Normal Force ◽  
Flow Volume ◽  
Flow Depth ◽  
Water Fraction ◽  
Force Fluctuations ◽  
Seismic Vibrations

<p>Debris flows are gravity-driven mass movements that are common natural hazards in mountain regions worldwide. Previous work has shown that measurements of ground vibrations are capable of detecting the timing, speed, and location of landslides and debris flows. A remaining question is whether or not additional flow properties, such as grain-size distribution, flow depth, and impact stress can be inferred reliably from seismic data. Here, we experimentally explore the relation of seismic vibrations and normal-force fluctuations with debris-flow composition and dynamics. We show that seismic vibrations and normal-force fluctuations induced by debris flows are strongly correlated, and that both are strongly affected by debris-flow composition. We find that the effects of the large-particle distribution on seismic vibrations and normal-force fluctuations are substantially more pronounced than the effects of water fraction, clay fraction, and flow volume, especially when normalized by flow depth. We further show that for flows with similar coarse-particle distributions seismic vibrations and normal-force fluctuations can be reasonably-well related to flow depth, even if total flow volume, water fraction, and the size distribution of fines varies. Our experimental results shed light on how changes in large-particle, clay, and water fractions affect the seismic and force-fluctuation signatures of debris flows, and provide important guidelines for their interpretation.</p>

scholarly journals Debris-flow volume quantile prediction from catchment morphometry

Geology ◽  
2019 ◽  
Vol 47 (8) ◽  
pp. 791-794 ◽  
Author(s):  
Tjalling de Haas ◽  
Alexander L. Densmore
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Volume Estimation ◽  
Catchment Characteristics ◽  
Reconstructed Volume ◽  
Elevation Data ◽  
Key Factor ◽  
Watershed Boundary ◽  
Catchment Morphometry ◽  
Frequency Curves

Abstract Estimation of the volumes of potential future debris flows is a key factor in hazard assessment and mitigation. Worldwide, however, there are few catchments for which detailed volume-frequency information is available. We (1) reconstructed volume-frequency curves for 10 debris-flow catchments in Saline Valley, California (USA), from a large number of well-preserved, unmodified surficial flow deposits, and (2) assessed the correlations between lobe-volume quantiles and a set of morphometric catchment characteristics. We found statistically significant correlations between lobe-volume quantiles, including median and maximum, and catchment relief, length (planimetric distance from the fan apex to the most distant point along the watershed boundary), perimeter, and Melton ratio (relief divided by the square root of catchment area). These findings show that it may be possible to roughly estimate debris-flow lobe-volume quantiles from basic catchment characteristics that can be obtained from globally available elevation data. This may assist in design-volume estimation for debris-flow catchments where past flow volumes are otherwise unknown.

Anticipating cascading risks at the imminent Hochvogel peak failure

2021 ◽  
Author(s):  
Johannes Leinauer ◽  
Manfred Meindl ◽  
Benjamin Jacobs ◽  
Verena Stammberger ◽  
Michael Krautblatter
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Point Clouds ◽  
Volume Estimation ◽  
Rock Fall ◽  
Recent Case ◽  
Hazard Evaluation ◽  
Event Analysis ◽  
Worst Case ◽  
Cascading Effects

<p>Climatic changes are exacerbating the risk of alpine mass movements for example through more frequent and extreme heavy precipitation events. To cope with this situation, the monitoring, anticipation, and early warning of rock slope failures based on process dynamics is a key strategy for alpine communities. However, only investigating the release area of an imminent event is insufficient, as the primary hazard can trigger or increase secondary hazards like debris flows or the damming of a river. Nevertheless, recent case studies dealing with successive hazards are rarely existent for the Calcareous Alps. In this study, we precisely investigate the cascading effects resulting from an imminent rock fall and perform a pre-event analysis instead of back-modelling of a past event.</p><p>The Hochvogel summit (2592 m a.s.l., Allgäu Alps, Germany/Austria) is divided by several pronounced clefts that separate multiple instable blocks. 3D-UAV point clouds reveal a potentially instable mass of 260,000 m³ in six main subunits. From our near real time monitoring system (Leinauer et al. 2020), we know that some cracks are opening at faster pace and react differently to heavy rainfall, making a successive failure of subunits likely. However, pre-deformations are not yet pronounced enough to decide on the exact expected volume whereas secondary effects are likely as the preparing rock fall mass will be deposited into highly debris-loaded channels. Therefore, we developed different rock fall scenarios from the gathered monitoring information, which we implemented into a RAMMS modelling of secondary debris flows. To obtain best- and worst-case results, each scenario is calculated with different erosion parameters in the runout channel. The models are calibrated with a well-documented debris flow event at Roßbichelgraben (10 km NW and similar lithology) and are supported by field investigations in the runout channel including electrical resistivity tomography profiles (ERT) for determination of the depth of erodible material as well as a drone survey for mapping the area and the generation of an elevation model.</p><p>Here we show a comprehensive scenario-based assessment for anticipating cascading risks at the Hochvogel from initial rock failure volume estimation to debris flow evolution and potential river damming. This recent case study from an alpine calcareous peak is an excellent and rare chance to gain insights into cascading risks modelling and an improved hazard evaluation.</p>

Comparison of methods for thyroid volume estimation in patients with Graves' disease

2003 ◽  
Vol 30 (4) ◽  
pp. 525-531 ◽  
Author(s):  
Johannes W. Isselt ◽  
John M. H. Klerk ◽  
Peter P. Rijk ◽  
Adrianus P. G. Gils ◽  
Lambertus J. Polman ◽  
...  
Keyword(s):  
Thyroid Volume ◽  
Volume Estimation ◽  
Graves Disease ◽  
Comparison Of Methods

scholarly journals Debris-flow modeling at Meretschibach and Bondasca catchments, Switzerland: sensitivity testing of field-data-based entrainment model

2017 ◽  
Vol 17 (5) ◽  
pp. 801-815 ◽  
Author(s):  
Florian Frank ◽  
Brian W. McArdell ◽  
Nicole Oggier ◽  
Patrick Baer ◽  
Marc Christen ◽  
...  
Keyword(s):  
Debris Flow ◽  
Field Data ◽  
Hazard Analysis ◽  
Flow Volume ◽  
Sensitivity Testing ◽  
Bed Erosion ◽  
Landslide Volume ◽  
Plausible Values ◽  
Sediment Entrainment ◽  
Basal Shear

Abstract. Debris-flow volumes can increase due to the incorporation of sediment into the flow as a consequence of channel-bed erosion along the flow path. This study describes a sensitivity analysis of the recently introduced RAMMS (Rapid Mass Movements) debris-flow entrainment model, which is intended to help solve problems related to predicting the runout of debris flows. The entrainment algorithm predicts the depth and rate of erosion as a function of basal shear stress based on an analysis of erosion measurements at the Illgraben catchment, Switzerland (Frank et al., 2015). Starting with a landslide-type initiation in the RAMMS model, the volume of entrained sediment was calculated for recent well-documented debris-flow events at the Bondasca and the Meretschibach catchments, Switzerland. The sensitivity to the initial landslide volume was investigated by systematically varying the initial landslide volume and comparing the resulting debris-flow volume with estimates from the field sites. In both cases, the friction coefficients in the RAMMS runout model were calibrated using the model, whereby the entrainment module was (1) inactivated to find plausible values for general flow properties by adjusting both coefficients (ξ and μ) and then (2) activated to further refine coefficient μ, which controls erosion (patterns). The results indicate that the model predicts plausible erosion volumes in comparison with field data. By including bulking due to entrainment in runout models, more realistic runout patterns are predicted in comparison to starting the model with the entire debris-flow volume (initial landslide plus entrained sediment). In particular, lateral bank overflow – not observed during these events – is prevented when using the sediment entrainment model, even in very steep (≈ 60–65 %) and narrow (4–6 m) torrent channels. Predicted sediment entrainment volumes are sensitive to the initial landslide volume, suggesting that the model may be useful for both reconstruction of historical events and the modeling of scenarios as part of a hazard analysis.

scholarly journals Debris flow modeling at Meretschibach and Bondasca catchment, Switzerland: sensitivity testing of field data-based erosion model

2016 ◽  
Author(s):  
Florian Frank ◽  
Brian W. McArdell ◽  
Nicole Oggier ◽  
Patrick Baer ◽  
Marc Christen ◽  
...  
Keyword(s):  
Debris Flow ◽  
Field Data ◽  
Hazard Analysis ◽  
Flow Volume ◽  
Flow Modeling ◽  
Sensitivity Testing ◽  
Bed Erosion ◽  
Landslide Volume ◽  
Sediment Entrainment ◽  
Basal Shear

Abstract. Debris flow volumes can increase due to the incorporation of sediment into the flow as a consequence of channel-bed erosion along the flow path. This study describes a sensitivity analysis of the recently-introduced RAMMS debris flow entrainment algorithm which is intended to help solve problems related to predicting the runout of debris flows. The entrainment algorithm predicts the depth and rate of erosion as a function of basal shear stress based on an analysis of erosion measurements at the Illgraben catchment, Switzerland (Frank et al., 2015). Starting with a landslide-type initiation in the RAMMS model, the volume of entrained sediment was calculated for recent well-documented debris-flow events at the Bondasca and the Meretschibach catchments, Switzerland. The sensitivity to the initial landslide volume was investigated by systematically varying the initial landslide volume and comparing the resulting debris-flow volume with estimates from the field sites. In both cases, the friction coefficients in the RAMMS runout model were calibrated using the model where the entrainment module was inactivated. The results indicate that the entrainment model predicts plausible erosion volumes in comparison with field data. By including bulking due to entrainment in runout models, more realistic runout patterns are predicted in comparison to starting the model with the entire debris-flow volume (initial landslide plus entrained sediment). In particular, lateral bank overflow – not observed during this event – is prevented when using the sediment entrainment model, even in very steep (≈ 60–65 %) and narrow (4–6 m) torrent channels. Predicted sediment entrainment volumes are sensitive to the initial landslide volume, suggesting that the model may be useful for both reconstruction of historical events as well as the modeling of scenarios as part of a hazard analysis.

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