Modelling woody material transport and deposition in alpine rivers

Mazzorana, Bruno; Hübl, Johannes; Zischg, Andreas Paul; Largiader, A.

doi:10.1007/s11069-009-9492-y

Cited by 98 publications

(95 citation statements)

References 20 publications

(19 reference statements)

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“…Indeed, modelling the dynamics of large wood in rivers during floods spurred a great deal of research in recent years (Benda et al, 2003;Mazzorana et al, 2009Mazzorana et al, , 2011Rigon et al, 2012;Ruiz-Villanueva et al, 2013b, 2014a. However, few studies have actually documented the effect of highmagnitude flash floods on LW dynamics collecting data on recruitment, transport and deposition rates, all information required in order to validate or develop new models on LW transport (Hassan et al, 2005).…”

Section: A Lucía Et Al: Dynamics Of Large Wood During a Flash Floodmentioning

confidence: 99%

Dynamics of large wood during a flash flood in two mountain catchments

Lucía¹,

Comiti

Borga

et al. 2015

Nat. Hazards Earth Syst. Sci.

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Abstract. Understanding and modelling the dynamics of large wood (LW) in rivers during flood events has spurred a great deal of research in recent years. However, few studies have documented the effect of high-magnitude flash floods on LW recruitment, transport and deposition. On 25 October 2011, the Magra river basin (north-western Italy) was hit by an intense rainstorm, with hourly rainfall rates up to 130 mm h −1 and event rain accumulations up to 540 mm in 8 h. Such large rainfall intensities originated flash floods in the main river channels and in several tributaries, causing severe damages and loss of lives. Numerous bridges were partly or fully clogged by LW jams. A post-flood survey was carried out along the channels of two catchments that were severely and similarly affected by this event, the Gravegnola (34.3 km 2 ) and Pogliaschina (25.1 km 2 ). The analysis highlighted a very relevant channel widening in many channel reaches, which was more marked in the Gravegnola basin due to highly erodible material forming the slopes adjacent to the fluvial corridor. Large wood recruitment rates were very high, up to 1270 m 3 km −1 , and most of it (70-80 %) was eroded from the floodplains as a consequence of channelwidening processes, while the rest came from hillslopes processes. Overall, drainage area and channel slope are the most relevant controlling variables in explaining the reach-scale variability of LW recruitment, whereas LW deposition appears to be more complex, as correlation analysis did not evidence any statistically significant relationship with the tested controlling variables. Indeed, in-channel LW displacement during the flood has been mostly limited by the presence of bridges, given the relatively large width attained by channels after the event.

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Section: A Lucía Et Al: Dynamics Of Large Wood During a Flash Floodmentioning

confidence: 99%

Dynamics of large wood during a flash flood in two mountain catchments

Lucía¹,

Comiti

Borga

et al. 2015

Nat. Hazards Earth Syst. Sci.

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“…There is no significant sediment recruitment downstream of the confluence and the sediment transport is driven by the upper Roize basin. x During high floods, the geomorphic adaptations downstream of the confluence can be huge: o Water discharge significantly increase due to the water input from relatively large Roizette catchment; o The sediment transport capacity increases thus considerably; o Small material mobilization may destabilize big boulders by scouring (Recking et al 2012a); o Increases in shear stresses and flow velocities possibly induce step-pools and armor breaking (Recking 2014); o Old woody debris jams that constitute natural sediment transport barriers (Heede 1985, Buffington andMontgomery 1999) are suddenly removed, freeing their trapped sediment stocks; o Stand trees topple in the bed, generating woody debris jam, diverting flows toward banks and promoting erosion and avulsion (Mazzorana et al 2009(Mazzorana et al , 2011. All these effects are strongly related to the flood magnitude and may create sort of threshold effects in flood hazards.…”

Section: Event-related Transportmentioning

confidence: 99%

Can bed-load help to validate hydrology studies in mountainous catchment? The case study of the Roize (Voreppe, France)

2016

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Abstract. Larges uncertainties are attached to hazard prediction in mountain streams, because of some limitations in our knowledge of physical processes, and overall, because of the lack of measurements for validation. This is particularly true for hydrological data, making the hydrology assessment of a mountain river a very difficult task, usually associated with large uncertainties. On the other hand, contrarily to lowland rivers, bed-load in mountain streams is often trapped in mitigation-structures, such as open check dams. This study aims to take advantage of these additional information for compensating the general lack of hydrological data, in order to converge toward a comprehensive diagnosis of the catchment hydrological behavior. A hydrology and sediment transport study has been done on the Roize torrent (16.1-km² -Voreppe -38-FR). After a classical historical study, a regional analysis of raingauges and water-discharge-stations situated in the calcareous north Pre-Alps massifs of the Vercors, Chartreuse and Bauges has been done. A catchment geomorphology study has been performed to get insight about the Roize torrential activity and sediment transport. The volumes of bed-load transported each year on average and during extreme floods have been computed using the estimated hydrology. The good bed-load predictions compare to the volume dredged in the Voreppe sediment trap are considered an indirect validation of the hydrology study.

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“…Floating wood is a source of hazard in many mountain streams (e.g., Comiti et al, 2006;Mazzorana et al, 2011;Rickenmann, 1997). For example, woody debris can jam in channel constrictions or at bridges, which may trap sediment and force water to overflow and leave the channel, ultimately causing overbank sedimentation.…”

Section: Mobility Of Large Woody Debris and Hazard Assessmentmentioning

confidence: 99%

“…Larger pieces of woody debris change flow hydraulics, and thus have an effect on flow J. M. Turowski et al: The mass distribution of coarse particulate organic matter velocity and sediment transport rates, which affects habitat and breeding grounds for fish and other aquatic animals (e.g., Abbe and Montgomery, 1996;Bilby and Ward, 1991;Brooks et al, 2004;Keller and Swanson, 1979;MacFarlane and Wohl, 2003;Montgomery and Piégay, 2003). Log jams are often a major element of stream morphology, and floating logs may pose a natural hazard (e.g., Comiti et al, 2006;Curran, 2010;Kraft and Warren, 2003;Manga and Kirchner, 2000;Mao et al, 2008;Mazzorana et al, 2011;Rickenmann, 1997).…”

Section: Introductionmentioning

confidence: 99%

The mass distribution of coarse particulate organic matter exported from an Alpine headwater stream

et al. 2013

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Abstract. Coarse particulate organic matter (CPOM) particles span sizes from 1 mm, with a dry mass less than 1 mg, to large logs and entire trees, which can have a dry mass of several hundred kilograms. Pieces of different size and mass play different roles in stream environments, from being the prime source of energy in stream ecosystems to macroscopically determining channel morphology and local hydraulics. We show that a single scaling exponent can describe the mass distribution of CPOM heavier than 0.1 g transported in the Erlenbach, a steep mountain stream in the Swiss pre-Alps. This exponent takes an average value of −1.8, is independent of discharge and valid for particle masses spanning almost seven orders of magnitude. Similarly, the mass distribution of in-stream large woody debris (LWD) in several Swiss streams can be described by power law scaling distributions, with exponents varying between −1.8 and −2.0, if all in-stream LWD is considered, and between −1.3 and −1.8 for material locked in log jams. We found similar values for in-stream and transported material in the literature. We had expected that scaling exponents are determined by stream type, vegetation, climate, substrate properties, and the connectivity between channels and hillslopes. However, none of the descriptor variables tested here, including drainage area, channel bed slope and the percentage of forested area, show a strong control on exponent value. Together with a rating curve of CPOM transport rates with discharge, the scaling exponents can be used in the design of measuring strategies and in natural hazard mitigation.

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Modelling woody material transport and deposition in alpine rivers

Cited by 98 publications

References 20 publications

Dynamics of large wood during a flash flood in two mountain catchments

Dynamics of large wood during a flash flood in two mountain catchments

Can bed-load help to validate hydrology studies in mountainous catchment? The case study of the Roize (Voreppe, France)

The mass distribution of coarse particulate organic matter exported from an Alpine headwater stream

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