Parameterization of a numerical 2-D debris flow model with entrainment: a case study of the Faucon catchment, Southern French Alps

Hussin, Haydar; Luna, B. Quan; Westen, C.J. van; Christen, Marc; Malet, Jean-Philippe; Asch, Th.W.J. van

doi:10.5194/nhess-12-3075-2012

Cited by 97 publications

(84 citation statements)

References 43 publications

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“…The RAMMS debris-flow runout model (rapid mass movement system) was selected for this project because it is already a widely used model for practical (e.g., Scheuner et al, 2011) as well as scientific debris flow applications (e.g., Hussin et al, 2012). However, it would be possible to incorporate the erosion algorithm into other debris flow runout models.…”

Section: Debris-flow Entrainment Modeling Methodsmentioning

confidence: 99%

“…Another approach relies on user-specified erosion layer properties (Beguería et al, 2009;Hungr and McDougall, 2009;Hussin et al, 2012) where the user predefines the volume or depth of eroded sediment. An example for this model type was implemented by Hussin et al (2012) within the RAMMS 2-D debris flow runout model . Hussin et al (2012) used a predefined entrainment method including one or more erosion layers with an absolute thickness specified by the model user wherein an erosion layer is instantaneously eroded when a user-specified critical shear stress is exceeded.…”

Section: F Frank Et Al: the Importance Of Entrainment And Bulking Omentioning

confidence: 99%

“…An example for this model type was implemented by Hussin et al (2012) within the RAMMS 2-D debris flow runout model . Hussin et al (2012) used a predefined entrainment method including one or more erosion layers with an absolute thickness specified by the model user wherein an erosion layer is instantaneously eroded when a user-specified critical shear stress is exceeded. This approach is based on the work of Sovilla et al (2006) for describing the entrainment of snow by avalanches.…”

Section: F Frank Et Al: the Importance Of Entrainment And Bulking Omentioning

confidence: 99%

“…Berger et al (2011) suggested that entrainment influences the motion of the debris flow because the entrained sediment has to be accelerated from a state of rest up to the speed of the flow; this could be visible in an additional resistance near the flow front. To include entrainment in a debris-flow model, Hussin et al (2012) predefined one or more erosion layers with a specific thickness which are fully eroded in their model when exceeding a critical shear stress. They noted that the entrainment method used in their erosion model showed high sensitivity to event volume and flow heights in their study at the Faucon catchment in the southern French Alps.…”

Section: Flow Properties and Runout Patternsmentioning

confidence: 99%

Section: F Frank Et Al: the Importance Of Entrainment And Bulking Omentioning

confidence: 99%

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The importance of entrainment and bulking on debris flow runout modeling: examples from the Swiss Alps

Frank

McArdell

Huggel

et al. 2015

Nat. Hazards Earth Syst. Sci.

130

137

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Abstract. This study describes an investigation of channelbed entrainment of sediment by debris flows. An entrainment model, developed using field data from debris flows at the Illgraben catchment, Switzerland, was incorporated into the existing RAMMS debris-flow model, which solves the 2-D shallow-water equations for granular flows. In the entrainment model, an empirical relationship between maximum shear stress and measured erosion is used to determine the maximum potential erosion depth. Additionally, the average rate of erosion, measured at the same field site, is used to constrain the erosion rate. The model predicts plausible erosion values in comparison with field data from highly erosive debris flow events at the Spreitgraben torrent channel, Switzerland in 2010, without any adjustment to the coefficients in the entrainment model. We find that by including bulking due to entrainment (e.g., by channel erosion) in runout models a more realistic flow pattern is produced than in simulations where entrainment is not included. In detail, simulations without entrainment show more lateral outflow from the channel where it has not been observed in the field. Therefore the entrainment model may be especially useful for practical applications such as hazard analysis and mapping, as well as scientific case studies of erosive debris flows.

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Section: Debris-flow Entrainment Modeling Methodsmentioning

confidence: 99%

Section: F Frank Et Al: the Importance Of Entrainment And Bulking Omentioning

confidence: 99%

Section: F Frank Et Al: the Importance Of Entrainment And Bulking Omentioning

confidence: 99%

Section: Flow Properties and Runout Patternsmentioning

confidence: 99%

Section: F Frank Et Al: the Importance Of Entrainment And Bulking Omentioning

confidence: 99%

See 3 more Smart Citations

The importance of entrainment and bulking on debris flow runout modeling: examples from the Swiss Alps

Frank

McArdell

Huggel

et al. 2015

Nat. Hazards Earth Syst. Sci.

130

137

View full text Add to dashboard Cite

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Entrainment of bed material by Earth‐surface mass flows: Review and reformulation of depth‐integrated theory

Iverson

Ouyang

2015

Reviews of Geophysics

247

142

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Earth-surface mass flows such as debris flows, rock avalanches, and dam-break floods can grow greatly in size and destructive potential by entraining bed material they encounter. Increasing use of depth-integrated mass and momentum conservation equations to model these erosive flows motivates a review of the underlying theory. Our review indicates that many existing models apply depth-integrated conservation principles incorrectly, leading to spurious inferences about the role of mass and momentum exchanges at flow-bed boundaries. Model discrepancies can be rectified by analyzing conservation of mass and momentum in a two-layer system consisting of a moving upper layer and static lower layer. Our analysis shows that erosion or deposition rates at the interface between layers must, in general, satisfy three jump conditions. These conditions impose constraints on valid erosion formulas, and they help determine the correct forms of depth-integrated conservation equations. Two of the three jump conditions are closely analogous to Rankine-Hugoniot conditions that describe the behavior of shocks in compressible gasses, and the third jump condition describes shear traction discontinuities that necessarily exist across eroding boundaries. Grain-fluid mixtures commonly behave as compressible materials as they undergo entrainment, because changes in bulk density occur as the mixtures mobilize and merge with an overriding flow. If no bulk density change occurs, then only the shear traction jump condition applies. Even for this special case, however, accurate formulation of depth-integrated momentum equations requires a clear distinction between boundary shear tractions that exist in the presence or absence of bed erosion.

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Deciphering controls for debris‐flow erosion derived from a LiDAR‐recorded extreme event and a calibrated numerical model (Roßbichelbach, Germany)

Dietrich

Krautblatter

2019

Earth Surf Processes Landf

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Debris flows are among the most destructive and hazardous mass movements on steep mountains. An understanding of debris‐flow erosion, entrainment and resulting volumes is a key requirement for modelling debris‐flow propagation and impact, as well as analysing the associated risks. As quantitative controls of erosion and entrainment are not well understood, total volume, runout and impact energies of debris flows are often significantly underestimated. Here, we present an analysis of geomorphic change induced by an erosive debris‐flow event in the German Alps in June 2015. More than 50 terrestrial laser scans of a 1.2 km long mountain torrent recorded geomorphic change in comparison to an airborne laser scan performed in 2007. Errors were calculated using a spatial variable threshold based on the point density of airborne laser scanning and terrestrial laser scanning and the slope of the digital elevation models. Highest erosion rates approach 5.0 m3/m2 (mean 0.6 m3/m2). During the event 9550 ± 1550 m3 was eroded whereas only 650 ± 150 m3 was deposited in the channel. Velocity, flow pressure, momentum and shear stress were calculated using a carefully calibrated RAMMS Debris Flow model including material entrainment. Here we present a linear regression model relating debris‐flow erosion rates to momentum and shear stress with an R2 up to 68%. Channel transitions from bedrock to loose debris sections cause excessive erosion up to 1 m3/m2 due to previously unreleased random kinetic energy now available for erosion. © 2019 John Wiley & Sons, Ltd.

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Parameterization of a numerical 2-D debris flow model with entrainment: a case study of the Faucon catchment, Southern French Alps

Cited by 97 publications

References 43 publications

The importance of entrainment and bulking on debris flow runout modeling: examples from the Swiss Alps

The importance of entrainment and bulking on debris flow runout modeling: examples from the Swiss Alps

Entrainment of bed material by Earth‐surface mass flows: Review and reformulation of depth‐integrated theory

Deciphering controls for debris‐flow erosion derived from a LiDAR‐recorded extreme event and a calibrated numerical model (Roßbichelbach, Germany)

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