An examination of controls on debris flow mobility: Evidence from coastal British Columbia

Guthrie, Richard; Hockin, Alexandra; Colquhoun, L.; Nagy, T.; Evans, Stephen G.; Ayles, Christopher P.

doi:10.1016/j.geomorph.2009.09.021

Cited by 75 publications

(47 citation statements)

References 42 publications

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“…By limiting flow volume forests act as an impediment that shortens the run-out zone. On steep slopes forests can even stop it (Guthrie et al 2010).…”

Section: Nais Stands and Measuresmentioning

confidence: 99%

Assessment of the protective function of forests against debris flows in a gorge of the Slovenian Alps

Fidej¹,

Mikoš²,

Rugani³

et al. 2015

iForest

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© iForest -Biogeosciences and Forestry IntroductionTraditional land use (agriculture and forestry) is being abandoned in the Alps due to socioeconomic changes, while an increasingly larger area is being used for tourism and infrastructure, which requires protection from natural hazards. Forests provide permanent protective functions, but only if they are properly and sustainably managed (Ott et al. 1997, O'Hara 2006, Mizunaga et al. 2010. There has been a general decline in forest management in Europe (Forest Europe 2010) and in the Alps in particular, where it is difficult to achieve positive economic returns (Schütz 1996). Climate change has increased the frequency of extraordinary weather phenomena, which causes higher risk from natural hazards and weakening of forest stability (Seidl et al. 2011). In many Alpine countries, state subsidies are used to facilitate the management of forests with direct protective functions (Mayer & Ott 1991, Brang et al. 2006. In order to maximize protective effects with minimal costs, a thorough understanding of natural hazards, their impact areas, and the potential role of forests is necessary (Lopez Saez et al. 2011). A detailed delineation of forest areas with direct protective functions is necessary to determine the areas where state subsidies should be directed. In addition, forest profile models must be developed to inform silvicultural measures and to verify their success (Mayer & Ott 1991, Berger & Rey 2004, Frehner et al. 2005.In Switzerland a method for the delineation of forests with direct protection functions was developed as part of the Silvaprotect-CH project: a standardized delineation of protection forests at the state level. The procedure involves multiple, stepwise modules that generate the actual forest areas with direct protection functions (Giamboni & Wehrli 2008). In France, the zoning classification of mountain forests with direct protection functions and the mapping of hazards and prohibition of the construction of infrastructure in risk areas were identified as the most effective preventive approach to ensure the maintenance of protective functions (Berger & Rey 2004). In Austria, a distinction is made between two types of protection forests: site-protection forests and infrastructure-protection forests, the latter also including forests that protect against noise and light pollution (Schima & Singer 2008). Delineation methods of forests in which slope processes (e.g., erosion, landslides, debris flow, etc.) are present differs among the federal states (Ziegner 2002).The negative effects of disturbances are best mitigated by uneven aged forests, where the presence and distribution of trees provide protection against natural hazards, and the ability to replace damaged trees with existing regeneration provides elasticity (O'Hara 2006). For such forests it is necessary to determine a (modified) selection forest target profile. In Switzerland the NaiS -Nachhaltigkeit und Erfolgskontrolle im Schutzwald is used for the management of protection forests (Fr...

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“…By limiting flow volume forests act as an impediment that shortens the run-out zone. On steep slopes forests can even stop it (Guthrie et al 2010).…”

Section: Nais Stands and Measuresmentioning

confidence: 99%

Assessment of the protective function of forests against debris flows in a gorge of the Slovenian Alps

Fidej¹,

Mikoš²,

Rugani³

et al. 2015

iForest

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“…Because the debris-flow process has often been observed to cause significant entrainment of sediment, which can strongly influence the flow (e.g., Dietrich and Dunne, 1978;Suwa and Okuda, 1980;Gallino and Pierson, 1984;Hungr et al, 1984;Benda, 1990;Pierson et al, 1990;Meyer and Wells, 1997;Vallance and Scott, 1997;Berti et al, 1999;Cannon and Reneau, 2000;Fannin and Wise, 2001;May, 2002;Wang et al, 2003;Revellino et al, 2004;Scott et al, 2005;Godt and Coe, 2007;Breien et al, 2008;Gartner et al, 2008;Pastor et al, 2009;Guthrie et al, 2010;Procter et al, 2010;Berger et al, 2010aBerger et al, , b, 2011Schürch et al, 2011;Iverson et al, 2011;McCoy et al, 2012;Cascini et al, 2014;Tobler et al, 2014;Frank et al, 2015), including entrainment and bulking debris-flow runout modeling would be appropriate. Processed-based entrainment rates using algorithms which consider the material properties of the debrisflow bulk (Crosta et al, 2003;D'Ambrosio et al, 2003;Medina et al, 2008; as well as pre-specified entrainment rates which pre-define the absolute volume of eroded material (Beguería et al, 2009;Hungr and McDougall, 2009;Hussin et al, 2012) have been introduced in numerical runout models.…”

Section: Introductionmentioning

confidence: 99%

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

Frank

McArdell

Oggier³

et al. 2017

Nat. Hazards Earth Syst. Sci.

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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.

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“…All of these flow changes control the capacity of lahars to modify the morphology of the channels where they flow, as observed in several studies (Muñoz-Salinas et al, 2008Doyle et al, 2009Doyle et al, , 2011Starheim et al, 2013;Andrés de Pablo et al, 2014), not only in volcanic environments, but also in mountainous regions in the form of debris flows. The role that the slope, the sediment availability, rainfall distribution and flow dynamics play, among other parameters, has been studied for a long time (e.g., Coe et al, 2008;Guthrie et al, 2010;Berger et al, 2011;Schürch et al, 2011;Abancó and Hürlimann, 2014;Theule et al, 2015), and has served to extrapolate these findings to volcanic conditions. Previous studies found that the highest erosion rates in river basins (10 5 -10 6 m 3 km −2 yr −1 ) correspond to active volcanoes under humid climate (Milliman and Syvitski, 1992;Walling and Webb, 1996;Major et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

“…These studies point out that the main factors affecting (E/D) rates are the amount of rainfall and volume of sediments available, the hydrologic characteristics of the streambottom deposits, the flow depth, and the morphology of the channel (Mizuyama and Kobashi, 1996;Fagents and Baloga, 2006;Berger et al, 2011;Okano et al, 2012;Thouret et al, 2014). Moreover, a number of studies address the issue of identifying governing factors of debris flow entrainment, and most of them have been carried out in laboratory (Mangeney et al, 2010;Iverson et al, 2011) or mountain environments (e.g., Chen et al, 2005;Hungr et al, 2005;Guthrie et al, 2010;Berger et al, 2011;McCoy et al, 2012;Abancó and Hürlimann, 2014;Theule et al, 2015). These latter studies show large scattered results, which suggests that mechanisms governing the entrainment are complex and depend on site and flow characteristics.…”

Section: Introductionmentioning

confidence: 99%

Factors controlling erosion/deposition phenomena related to lahars at Volcán de Colima, Mexico

Vázquez

Capra

Coviello

2016

Nat. Hazards Earth Syst. Sci.

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Abstract. One of the most common phenomena at Volcán de Colima is the annual development of lahars that runs mainly through the southern ravines of the edifice. Since 2011 the study and the monitoring of these flows and of the associated rainfall has been achieved by means of an instrumented station located along the Montegrande ravine, together with the systematic surveying of cross-topographic profiles of the main channel. From these, we present the comparison of the morphological changes experimented by this ravine during the 2013, 2014 and 2015 rainy seasons. The erosion/deposition effects of 11 lahars that occurred during this period of time were quantified by means of the topographic profiles taken at the beginning and at the end of the rainy seasons and before and after the major lahar event of 11 June 2013. We identified (i) an erosive zone between 2100 and 1950 m a.s.l., 8 • in slope, with an annual erosional rate of 10.3 % mainly due to the narrowness of the channel and to its high slope angle and (ii) an erosive-depositional zone, between 1900 and 1700 m a.s.l., (∼ 8 % erosion and ∼ 16 % deposition), characterized by a wider channel that decreases in slope angle (4 • ). Based on these observations, the major factors controlling the erosion/deposition rates in the Montegrande ravine are the morphology of the gully (i.e., channel bed slope and the cross section width) and the joint effect of sediment availability and accumulated rainfall. On the distal reach of the ravine, the erosion/deposition processes tend to be promoted preferentially one over the other, mostly depending on the width of the active channel. Only for extraordinary rainfall events are the largest lahars mostly erosive all along the ravine up to the distal fan where the deposition takes place. In addition, as well as the morphological characteristics of the ravine, the flow depth is a critical factor in controlling erosion, as deeper flows will promote erosion against deposition. Finally, by comparing rainfalls associated with lahars that originated after the last main eruptive episode that occurred in 2004-2005, we observed that higher accumulated rainfall was needed to trigger lahars in the 2013 and 2014 seasons, which points to a progressive stabilization of the volcano slope during a post-eruptive period. These results can be used as a tool to foresee the channel response to future volcanic activity, to improve the input parameters for lahar modeling and to better constrain the hazard zonation at Volcán de Colima.

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An examination of controls on debris flow mobility: Evidence from coastal British Columbia

Cited by 75 publications

References 42 publications

Assessment of the protective function of forests against debris flows in a gorge of the Slovenian Alps

Assessment of the protective function of forests against debris flows in a gorge of the Slovenian Alps

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

Factors controlling erosion/deposition phenomena related to lahars at Volcán de Colima, Mexico

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