Hydrogeomorphic processes in a steep debris flow initiation zone

Imaizumi, Fumitoshi; Sidle, Roy C.; Tsuchiya, Satoshi; Ohsaka, Okihiro

doi:10.1029/2006gl026250

Cited by 95 publications

(94 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The general patterns of spatial and temporal variability of geomorphic responses in the Manival catchment is consistent with other recent reported monitoring studies on sediment dynamic in debris-flow channels (Berger et al, 2011a;Fuller and Marden, 2010;Imaizumi et al, 2006;McCoy et al, 2010;Remaître et al, 2005). The pulses of sediment supply from hillslopes during the winter accumulated in first-order channels and are transferred to their next higher order reaches during spring and summer storms by debrisflows.…”

Section: Discussionsupporting

confidence: 90%

“…The SLBL has been initially defined as a surface above which has rocks that are assumed to be erodible by landsliding (Jaboyedoff et al, 2004) and the method was adapted to estimate the sediment infilling of glacial U-shape valleys (Jaboyedoff and Derron, 2005;Otto et al, 2009). The general principle is to deepen DTM pixels included in the alluvial fill by an iterative routine until an assumed bedrock surface shape is reconstructed.…”

Section: Initial Channel Storage Quantificationmentioning

confidence: 99%

“…Degradation phases are related to bedload transport events during autumn. Observations of a first-order channel in Japan showed sediment accumulation during winter freeze-thaw cycles, and channel scouring during summer convective storms (Imaizumi et al, 2006). Most of the sediment flushing was driven by debrisflows while bedload transport was considered as a minor sediment transport process.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Sediment budget monitoring of debris-flow and bedload transport in the Manival Torrent, SE France

Theule¹,

Liébault²,

Loye³

et al. 2012

Nat. Hazards Earth Syst. Sci.

115

View full text Add to dashboard Cite

Abstract. 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 routing during moderate rainfall intensities which occur several times each year. The monitoring was based on intensive topographic resurveys of low-and high-order channels using different techniques (cross-section surveys with total station and high-resolution channel surveys with terrestrial and airborne laser scanning). Data on sediment output volumes from the main channel were obtained by a sediment trap. Two debris-flows were observed, as well as several bedload transport flow events. Sediment budget analysis of the two debris-flows revealed that most of the debris-flow volumes were supplied by channel scouring (more than 92 %). Bedload transport during autumn contributed to the sediment recharge of high-order channels by the deposition of large gravel wedges. This process is recognized as being fundamental for debris-flow occurrence during the subsequent spring and summer. A time shift of scour-and-fill sequences was observed between low-and high-order channels, revealing the discontinuous sediment transfer in the catchment during common flow events. A conceptual model of sediment routing for different event magnitude is proposed.

show abstract

Section: Discussionsupporting

confidence: 90%

Section: Initial Channel Storage Quantificationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Sediment budget monitoring of debris-flow and bedload transport in the Manival Torrent, SE France

Theule¹,

Liébault²,

Loye³

et al. 2012

Nat. Hazards Earth Syst. Sci.

115

View full text Add to dashboard Cite

show abstract

“…These local, intense, convective rainfalls (Underwood et al, submitted) produce abundant runoffs at the feet of rocky headwater walls that are able to entrain large quantities of sediments and debris flows. Runoffgenerated debris flows, initially observed in laboratory facilities (Gregoretti, 2000a,b;Tognacca et al, 2000), are common both in the Alpine region (Berti and Simoni, 2005;Gregoretti and Dalla Fontana, 2008;Theule et al, 2012;Tiranti and Deangeli, 2015) and in other mountainous regions such as the Pyrenees (Hurlimann et al, 2014), Japan Alps (Imaizumi et al, 2006;Okano et al, 2012), Colorado and California (Cannon et al, 2008;Coe et al, 2008;Kean et al, 2012). The routing of debris flow in settled areas can cause damage and casualties.…”

Section: Introductionmentioning

confidence: 99%

Comparative analysis of the differences between using LiDAR and contour-based DEMs for hydrological modeling of runoff generating debris flows in the Dolomites

2015

View full text Add to dashboard Cite

Present work aims to explore the differences in hydrological modeling when using digital elevation models (DEMs) generated by points from LiDAR surveys and those digitized on the contour lines of the regional technical map (RTM) and their relevance for the simulation of debris flow triggering. Hydrological models for mountainous areas are usually based on DEMs. DEMs are used to determine the flow path from each pixel, by which the basin is discretized, to the outlet. Hydrological simulations of runoff that triggered debris flows occurred in two rocky headwater basins of Dolomites, Fiames Dimai (area approximately 0.03 km 2 ), and Cancia (area approximately 0.7 km 2 ) are carried out using a DEM-based model designed for simulating runoff that descends from headwater areas. For each basin, the runoff is simulated using DEMs that are generated using points from LiDAR, and those digitized on the contour lines of the regional technical map, respectively. The results show that the peak discharge values corresponding to the simulations carried out using the LiDAR-based DEMs are higher than those corresponding to the simulations carried out using the RTM-based DEMs. Larger differences are observed for the Dimai basin, where the area corresponding to the RTM-based DEM is markedly smaller than the area corresponding to LiDAR-based DEM, whereas for the Cancia basin, the two areas are similar. Both the differences in the peak discharge and the basin area are due to the poor accuracy of the contour-based DEM (i.e., elevation accuracy), that is, a poor representation of the morphological features that leads to errors on the watershed divide and simplifications of the flow paths from each cell to the outlet. This result is highly relevant for estimating the triggering conditions of runoff generated debris flows. An incorrect simulated value of peak discharge can lead to errors both in planning countermeasures against debris flows and in predicting their occurrence.

show abstract

“…The Southern Japanese Alps is characterized as a humid periglacial area because of abundant annual precipitation (>2500 mm) and frequent freeze-thaw cycles during winter, especially at mid elevation mountain ranges (e.g., 1000 to 2000 30 m) (Imaizumi et al, 2006;Imaizumi et al, 2017). Gravitational sediment transport processes (e.g., soil creep and dry ravel), which have been poorly studied in relation to vegetation change, are more important sediment transport processes than surface wash because of the steep terrain (Imaizumi et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Forest harvesting impacts on micrometeorological conditions and sediment transport activities in a humid periglacial environment

Imaizumi

Nishii

Ueno

et al. 2018

Preprint

Self Cite

View full text Add to dashboard Cite

Abstract. Sediment transport activities in the periglacial environment are controlled by hillslopes micrometeorological conditions (i.e., air and ground temperatures, ground water content), which are highly affected by vegetation cover. Thus, there is a possibility that forest harvesting, which is the most dramatic change to vegetation cover in mountain areas, may severely impact sediment transport activities in periglacial areas (i.e., soil creep, dry ravel). Knowledge of the effects of forest harvesting on sediment transport are needed to protect aquatic ecosystems as well as to develop better mitigation 15 measures for preventing sediment disasters. In this study, we investigated changes in sediment transport activities following forest harvesting in steep artificial forests located in a humid periglacial area of the Southern Japanese Alps. In the Southern Japanese Alps, rainfall is abundant in summer and autumn, and air temperatures frequently rise above and fall below 0 degrees in the winter. Our monitoring by time laps cameras revealed that gravitational transport processes (e.g., frost creep and dry ravel) dominate during the freeze-thaw season, while rainfall-induced processes (surface erosion and soil creep) 20 occur during heavy rainfall seasons. Removal of the forest canopy by forest harvesting alters the type of winter soil creep from deeper frost creep to diurnal needle-ice creep. Winter creep velocity of the ground surface sediment in the harvested site was significantly higher than that in the non-harvested site. Meanwhile, sediment flux on the hillslopes observed by sediment traps decreased in the harvested site. Branches of harvested trees left on the hillslopes captured sediment coming from upslope. In addition, the growth of understories after harvesting possibly reduced surface erosion. Consequently, 25 removal of the forest canopy by forest harvesting directly impacts micrometeorological conditions and periglacial sediment transport activity, while sediment flux on hillslopes is also affected by branches left on the hillslopes and recovery of understories.

show abstract

Hydrogeomorphic processes in a steep debris flow initiation zone

Cited by 95 publications

References 11 publications

Sediment budget monitoring of debris-flow and bedload transport in the Manival Torrent, SE France

Sediment budget monitoring of debris-flow and bedload transport in the Manival Torrent, SE France

Comparative analysis of the differences between using LiDAR and contour-based DEMs for hydrological modeling of runoff generating debris flows in the Dolomites

Forest harvesting impacts on micrometeorological conditions and sediment transport activities in a humid periglacial environment

Contact Info

Product

Resources

About