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The 1987 debris flows in Switzerland: documentation and analysis

The 1987 debris flows in Switzerland: documentation and analysis
Alps (The) ; Catastrophe ; Debris flow ; Flood ; Mountain ; Slope ; Slope dynamics ; Slope gradient ; Switzerland
A great number of debris flows occurred during the flood catastrophes of the summer of 1987 in the Swiss Alps. Aerial photography, field investigations and eyewitness accounts documented and analysed the events. Apart from incision into weak bedrock
to estimate the most important flow parameters. These values are compared to debris flow data from Canada and Japan.

Flow structure at an asymmetrical stream confluence

Flow structure at an asymmetrical stream confluence
Carrying capacity ; Confluent ; Fluvial hydrology ; Hydrodynamics ; Illinois ; Stream ; Stream flow ; United States of America ; Water temperature
, the study focuses on patterns of flow separation, flow convergence/divergence, and secondary circulation immediately downstream from the confluence, and the relationship of these patterns to the mixing interface between the combining flows.

Debris flows as geomorphic agents in the Huachuca Mountains of southeastern Arizona

Debris flows as geomorphic agents in the Huachuca Mountains of southeastern Arizona
By examining evidence left by historical debris flows, which occured in 1988 and 1977, and debris-flow deposits dating back to the Pleistocene, the AA. were able to draw inferences about controls on debris-flow occurence and the geomorphic role
of debris flows in this semiarid mountain range.

A DISCUSSION AND CLASSIFICATION OF SUBAQUEOUS MASS-TRANSPORT WITH PARTICULAR APPLICATION TO GRAIN-FLOW, SLURRY-FLOW, AND FLUXOTURBIDITES

A DISCUSSION AND CLASSIFICATION OF SUBAQUEOUS MASS-TRANSPORT WITH PARTICULAR APPLICATION TO GRAIN-FLOW, SLURRY-FLOW, AND FLUXOTURBIDITES
BIBLIOGRAPHIE ; COURANT D'INERTIE ; FLUXOTURBIDITE ; FONDS SOUS-MARINS ; GEOMORPHODYNAMIQUE ; GRAIN FLOW ; Géographie physique ; MISE AU POINT ; MOUVEMENT DE MASSE ; SLURRY FLOW ; TURBIDITE ; TYPOLOGIE

Debris flows involved in the development of Pleistocene stratified slope deposits in Periglacial processes and landforms.

Debris flows involved in the development of Pleistocene stratified slope deposits in Periglacial processes and landforms.
Two approaches to this problem : 1) the analysis of recent debris flows within an Alpine environment, and 2) laboratory experiments, simulating debris flows under different conditions. Sedimentological characteristics of debris flow material
are discussed, as well as relationships between physical and sedimentological properties. Resulting criteria for the recognition of debris flow material are given and the role of temperature is treated briefly.

Measuring river velocities using GPS River Flow Tracers (GRiFTers)

Measuring river velocities using GPS River Flow Tracers (GRiFTers)
England ; Fluvial dynamics ; Global Positioning System ; Ground survey ; Methodology ; Stream ; Stream flow ; United Kingdom
This paper introduces the use of GPS drifters (termed GRiFTers) to measure surface flow velocities in a 400 m reach of the River Swale, UK. The technique shows great promise to provide new insights into flow patterns over long reaches of rivers
, over a range of flow conditions, and may also provide valuable data for numerical model validation.

Hyporheic flow as a potential geomorphic agent in the evolution of channel morphology in a gravel-bed river

Hyporheic flow as a potential geomorphic agent in the evolution of channel morphology in a gravel-bed river
Bank erosion ; Channel geometry ; Floodplain ; Hokkaido ; Hydrochemistry ; Japan ; Meander ; Stream ; Stream flow
This study examined Takahashi and Sasa's hypothesis of the influence of hyporheic flows on changes in channel form, particularly the formation of head-cut gullies, in an alluvial floodplain. A combination of hyporheic flow (sapping erosion
) and channel erosion (bank erosion) appeared to contribute to the formation of the head-cut gullies. Hyporheic flow is an important component in the geomorphic evolution of channels and the floodplain in a gravel-bed river.

Sediment-transport competence of rain-impacted interrill overland flow

Sediment-transport competence of rain-impacted interrill overland flow
This paper investigates the transport of particles in shallow, rain-impacted flow. Specifically the relationships among rainfall energy, flow energy and transport distance will be investigated. From this investigation a definition of competence
for such flow in terms of transport distance (i.e. a finite distance in a finite time) will be presented. Using the data obtained from the investigation, a predictive equation for sediment-transport competence of rain-impacted shallow flow will be developed.

The effect of bedload transport on mean and turbulent flow properties

The effect of bedload transport on mean and turbulent flow properties
Carrying capacity ; Energy balance ; Experimentation ; Roughness ; Runoff ; Stream ; Stream flow ; Turbulence
This paper present the results of a flume experiment that was designed to investigate the effect of bedload transport on mean and turbulent properties of the flow. The data obtained from the experiment show that bedload transport may either cause
the flow to decelerate or accelerate , depending on the roughness of the bed, hydraulic conditions, and bedload transport rate. A deeper understanding of the feedback effects of bedload is gained by taking into account the turbulent component of the flow.

Effects of a pebble cluster on the turbulent structure of a depth-limited flow in a gravel-bed river

Effects of a pebble cluster on the turbulent structure of a depth-limited flow in a gravel-bed river
Canada ; Gravel ; Hydrodynamics ; Micromorphology ; Quebec ; Stream ; Stream flow ; Turbulence
This paper presents original results from measurements of velocity taken at a high spatial and temporal resolution in a turbulent flow upstream and downstream from a pebble cluster. The high sampling resolutions in a natural environment permitted
characterization of the complex dynamics of the turbulent flow in the vicinity of the cluster. The description of these dynamics is based on the interpretation of contour maps of several turbulence statistics. Results indicate the existence of highly dynamic
boundaries between zones where strong intermittent events are generated. They also highlight the difference between shedding and upwelling motions of the flow.

Influence of experimental removal of large woody debris on spatial patterns of three-dimensional flow in a meander bend

Influence of experimental removal of large woody debris on spatial patterns of three-dimensional flow in a meander bend
Channel geometry ; Experimentation ; Meander ; Midwest ; Model ; Stream ; Stream flow ; United States of America
This study reports the results of a large woody debris (LWD) removal experiment in a meander bend along a low-energy stream in the Midwestern United States. The results indicate that the LWD obstruction influenced 3D flow structure in this bend
at all flow stages. After the removal of LWD from the bend, both downstream and secondary velocities increased and, though still weak, secondary flow intensified.

Partitioning resistance to overland flow on rough mobile beds

Partitioning resistance to overland flow on rough mobile beds
Comparative study ; Experimentation ; Hydrology ; Methodology ; Overland flow ; Roughness ; Runoff ; Sediment load ; Slope gradient
The aim of this study is to evaluate the effect of bed mobility on resistance to overland flow on rough beds. This is done by analyzing 2 series of flume experiments with similar hydraulic and bed roughness characteristics. In the first series
the water is free of sediment and flows over a fixed bed, whereas in the second the water is laden with sediment and flows over a mobile bed. Discussion of the results.

Lava flows of Mount Rouse, Western Victoria

Lava flows of Mount Rouse, Western Victoria
Mt Rouse, an exctint volcano south of Penshurst in W. Victoria was a source for copious lava flows which followed pre-existing valleys and reached the coast 60 km to the south. Many typical features of drainage modifications are associated
with the lava flows. Stony rises are widespread and it is deduced that a lava tube mechanism was in operation to produce such long flows. A new date for the volcano is 1,8 m.y., which is inconsistent with ages of about 0,3 m.y. reported from basalts near Port
Fairy. The Mt Rouse flows serve as a useful market for distinguishing Pleistocene from older volcanoes in this region. (E.C.F.B.).

Particle travel distances and bed and sediment compositions associated with rain-impacted flows

Particle travel distances and bed and sediment compositions associated with rain-impacted flows
Laboratory experiments were performed with rain of uniform drop size impacting flows over non-cohesive beds of uniform sized sand and coal particles with flow velocities that were insufficient for the flow to entrain the particles without the aid
of the impact of the soil in process-based models of erosion by rain-impacted flow.

Flow disturbance caused by cross-stream coarse woody debris

Flow disturbance caused by cross-stream coarse woody debris
Canada ; Channel geometry ; Hydraulic works ; Ontario ; River bed ; Roughness ; Spatial analysis ; Stream ; Stream flow ; Turbulence ; Wood
The aim of this study is to identify the spatial extent of flow disturbance caused by coarse woody debris positioned normal to the flow between 75° and 105°to the downstream flow direction. A reprsentative reach of the Pine River, Ontario, was used

A stability criterion inherent in laws governing alluvial channel flow

A stability criterion inherent in laws governing alluvial channel flow
Carrying capacity ; Channel geometry ; Mathematical hydrology ; Runoff ; Sediment transport ; Stream ; Stream flow
The stability criterion of maximum flow efficiency (MFE) has previously been found inherent in typical alluvial channel flow relationships, and this study investigates the general nature of this criterion using a wider range of flow resistance

Reach scale variability of turbulent flow characteristics in a gravel-bed river

Reach scale variability of turbulent flow characteristics in a gravel-bed river
Fluid flow and sediment transport processes in geomorphology : innovations, insights, and advances in measurement
The AA. examine the effects of roughness elements on the spatial variability of the mean flow velocity profiles and of the properties of turbulent flow structures at the reach scale. The experiment was carried out in 2 reaches of 25 m long
in the Eaton North River (Québec). At the reach scale, the distribution of individual roughness elements does not greatly control the spatial variability of turbulent flow properties.

Geomorphological characteristics of small debris flows on Junior's Kop, Marion Island, maritime sub-Antarctic

Geomorphological characteristics of small debris flows on Junior's Kop, Marion Island, maritime sub-Antarctic
The geomorphological characteristics of small debris flows in a maritime sub-Antarctic environment are described. The morphological and sedimentological characteristics of the debris flows are comparable to debris flows documented for other parts
of the world; their initiation appears closely linked to the unusual environment in which they are found. The debris flows are triggered by sediment mobilization upon saturation of the frost-heaved surface gravel and overland flow over the low-permeability
and frost-susceptible slope materials. Morphological effects of the flows are short-lived due to obliteration by subsequent frost heave activity.

Re-assessment of the monthly naturalized flow record for the River Thames at Kingston since 1883, and the implications for the relative severity of historical droughts

Re-assessment of the monthly naturalized flow record for the River Thames at Kingston since 1883, and the implications for the relative severity of historical droughts
Discharge ; Drought ; England ; Fluvial hydrology ; Model ; Precipitation ; Stream ; Stream flow ; United Kingdom
A rainfall-streamflow modelling methodology is applied to the monthly flow record for the Thames at Kingston, one of the most important long records of river flow, from 1883. The results confirm that low flows during droughts before about 1950 have
been underestimated. It is argued that, consequently, recent droughts have been more severe than suggested by analyses of the existing Kingston flow record taken at face value. The distinction between gauged and naturalized flows at Kingston

A rational method for estimating maximum discharge of a landslide-induced debris flow : a case study from southwestern China

A rational method for estimating maximum discharge of a landslide-induced debris flow : a case study from southwestern China
China ; Debris flow ; Discharge ; Forecast ; High mountain ; Landslide ; Methodology ; Mountain ; Natural hazards ; Sichuan ; Slope dynamics
The proposed method was applied to an actual landslide-induced debris flow that occurred on June 13, 1995 in a high-altitude mountainous region of southwestern China. The method depends on field measurements of channel dimensions and some empirical
equations for debris flow dynamics. Maximum discharge is one of the most important characteristics of debris flows, because it can be used for assessing the hazard potential of debris flows and for developing preventive measures to reduce the dynamic impacts
of debris flows.

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