Joshua TheuleCentre de Recherche sur l´Environnement Alpin | CREALP
Joshua Theule
PhD
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Publications (37)
In steep channels, debris flows are known to dramatically increase in volume under the effect of channel erosion. However, the critical factors controlling channel erosion by debris flows are not well documented by field studies. This is particularly true for the effect of slope on the depth at which erodible beds are scoured during debris flows an...
Steep mountain catchments typically experience large sediment pulses
from hillslopes which are stored in headwater channels and remobilized
by debris-flows or bedload transport. Event-based sediment budget
monitoring in the active Manival debris-flow torrent in the French Alps
during a two-year period gave insights into the catchment-scale sediment...
Structural settings and lithological characteristics are traditionally assumed to influence the development of erosional landforms, such as gully networks and rock couloirs, in steep mountain rock basins. The structural control of erosion of two small alpine catchments of distinctive rock types is evaluated by comparing the correspondences between...
Many debris flows have significant amounts of entrainment, resulting in a substantially larger final volume than their initial volume and more complicated mechanics and characteristics of the flow. This chapter reviews some historical cases with substantial entrainment and erosion mechanisms that have been commonly considered in studying debris flo...
Proglacial areas in high-mountain environments are among the most dynamic landscape zones in terms of morphological, sedimentological, and hydrological changes. In fact, in such areas both glacial and paraglacial dynamics exert a strong control on water fluxes (and thus on bedload transport capacity) and on sediment supply. Because of the rapid cha...
In mountain basins, long-term instrumental monitoring coupled with high-resolution topographic surveys can provide important information on sediment yield. The Gadria catchment, located in the eastern Italian Alps, typically features several low-magnitude flood episodes and a few debris-flow events per year, from late spring to late summer. Beginni...
The present study explores the evolutionary trajectory of the glacier-fed Mareit River (South Tyrol, Italian Alps), where
a large restoration programme was implemented in 2008–2009. River corridor changes before and after the restoration works were
assessed using historical maps, recent field observations, topographic surveys and topographic differ...
In mountainous catchments, the quantification of sediment yield is of paramount relevance for land-use planning and design of sediment control structures. However, deciphering the contribution of the different sediment transport processes (debris flows, debris floods and bedload transport) is often challenging as they are strongly controlled by bas...
The assessment of flow velocity has a central role in quantitative analysis of debris flows, both for the characterization of the phenomenology of these processes and for the assessment of related hazards. Large-scale particle image velocimetry (LSPIV) can contribute to the assessment of surface velocity of debris flows, provided that the specific...
Objectives The objective of this work is to asses different techniques for evaluating riverbed morphological changes and sediment redistribution in a restored river reach. Methods The study was carried out in a restored reach of the Mareiter river, in South Tyrol, Italy. Methods used are (1) repeated cross-section surveys by total station (TS) and...
L’usage de données topographiques à haute résolution de type LiDAR ou photogrammétrie SfM tend à se
développer au sein des services RTM compte tenu de l’offre de plus en plus importante. Il n’est plus rare de
disposer sur un même lieu géographique de plusieurs modèles numériques de terrain issus de campagnes
d’acquisition successives. Il est alors...
Debris flows have been recognized to be linked to the amounts of material temporarily stored in torrent channels. Hence, sediment supply and storage changes from low-order channels of the Manival catchment, a small tributary valley with an active torrent system located exclusively in sedimentary rocks of the Chartreuse Massif (French Alps), were su...
Debris flows have been recognized to be linked to amounts of material temporary stored in torrent channels. Consequently, sediment production, debris supply and storage changes from low-order channels of the Manival catchment (French Alps) were surveyed periodically during 16 months using terrestrial laser scanning (TLS) to study the coupling betwe...
Debris-flows are known to have important volume growth from channel erosion on steep slopes. However, it is still difficult to quantify the relationship of debris-flow scouring and slope. High densities of multi-date cross-sections in both the Manival and Real debris-flow catchments (French Alps) have clearly shown that debris-flows have significan...
A permanent field installation for the systematic test of debris flow
warning systems and algorithms has been equipped on the eastern Italian
Alps. The installation was also designed to produce didactic videos and it
may host informative visits. The populace education is essential and should
be envisaged in planning any research on hazard mitigatio...
Early warning systems (EWSs) are among the measures adopted for the mitigation of debris flow
hazards. EWSs often employ algorithms that require careful and long testing to grant their
effectiveness. A permanent installation has been so equipped in the Gadria basin (Eastern Italian
Alps) for the systematic test of event-EWSs. The installation is co...
Debris-flows are known to have important volume growth from channel erosion on steep slopes. However, it is still difficult to quantify the relationship of debris-flow scouring and slope. High densities of multi-date cross-sections in both the Manival and Real debris-flow catchments (French Alps) have clearly shown that debris-flows have significan...
The estimation of debris-flow volume is a fundamental task for the design of any hazard mitigation intervention in a mountain channel. The estimation may be carried out before the occurrence of a debris flow through methodologies aimed at assessing the debris potential in the basin. It can be carried out through instrumentation deployed along the t...
Debris-flow monitoring in instrumented areas is an invaluable way to gather field data that may improve the understanding of these hazardous phenomena. A new experimental site has been equipped in the Autonomous Province of Bozen-Bolzano (Eastern Alps, Italy) for both monitoring purposes and testing early warning systems. The study site (Gadria bas...
Ce papier présente les enjeux scientifiques, opérationnels et techniques d'un observatoire de mesure des crues et laves torrentielles installé en 2010 sur cinq torrents des Alpes françaises (isère et Alpes-Maritimes). Couplée à des relevés topographiques à haute-résolution et des données pluviométriques spatialisées, ce type d'installation, encore...
Steep mountain catchments typically experience large sediment pulses from hillslopes which are stored in headwater channels and remobilized by debris-flows or bedload transport. The purpose of this research was to investigate the coarse sediment transport through steep catchments and how channel storage can influence debris-flows. This required int...
Debris-flows mobilize high sediment loads and are often responsible for most of the sediment yield from upland headwaters and may endanger the safety of life and infrastructure in the vicinity of torrent channels. Two very active debris-flow torrents with different physiographic settings have been equipped in the French Alps, the Manival Torrent (3...
Steep mountain catchments typically experience sediment pulses from
hillslopes which are stored in headwater channels and flushed out by
debris-flows. Event-based sediment budget monitoring in two active
debris-flow torrents in the French Alps (Manival and Réal) during
a two-year period gave insights about catchment-scale sediment routing
during ra...
Small upland catchments in degraded terrains are prone to debris-flows which may endanger the safety of life and infrastructure in the vicinity of torrent channels. These flows mobilise high sediment loads and they are often responsible for most of the sediment yield from upland headwaters. Despite their importance in terms of natural hazard preven...
Rock slope instabilities are implicitly linked to the supply of sediment and debris recharging channels prone to debris flow. Hence, the incorporation of bedrock structure and terrain morphology can be relevant in the analysis of sediment budget and debris flow hazard assessment. Here, the mode of debris production of the Manival catchment (norther...
The Manival near Grenoble (French Prealps) is a very active debris-flow torrent equipped with a large sediment trap (25 000 m 3) protecting an urbanized alluvial fan from debris-flows. We began monitoring the sediment budget of the catchment controlled by the trap in Spring 2009. Terrestrial laser scanner is used for monitoring topographic changes...
The monitoring of sediment transport in the Manival Torrent and its catchment (Chartreuse mountain range, France) began in spring 2009 with a sediment budget approach. The objective is to explore topographic, spatial, and morphologic correlations with sediment transport activities throughout the catchment and its torrent channel. The catchment area...
Quantification of volumes for coarse sediment transport in small upland catchments is of great concern for the protection and prevention against flood hazards in mountainous terrains. This contribution presents a starting research project dedicated to the characterization and prediction of the sediment responses of small alpine catchments. The main...
Manival Torrent, a small mountain stream located in the Northern French Prealps, experiences debris flows annually. The torrents catchment (3.6 km2, 1,200 m relief) is composed of marl and limestone beds with increasing limestone towards the ridge. A field monitoring program started in 2009 to study the geomorphic responses to flow events. The aim...