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  • High-resolution analysis of debris flow-induced channel changes in a headwater stream, Ashio Mountains, Japan
  • Channel geometry ; Debris flow ; Fluvial dynamics ; Geomorphometry ; Geophysics ; Honshu ; Japan ; Mountain ; Sampling ; Stream
  • Changes in channel size and shape caused by a debris flow event along the length of a headwater stream (HWS) in the Ashio Mountains were captured with the aid of repeat high-definition surveys using terrestrial laser scanning (TLS) techniques
  • . The HWS was classified into 3 distinct reaches below the debris flow initiation zone. Morphometric analyses from the TLS point cloud revealed that debris flow erosion produced a distinct nonlinear change in channel dimensions in the downstream direction
  • 2009
  • Detachment of road surface soil by flowing water
  • to flow depth, slope gradient and other hydraulic parameters such as shear stress, stream power and unit stream power. Multiple non-linear regression analyses indicate that detachment rates for all roads can be accurately predicted by power functions
  • of flow depth and slope gradient. According to the experimental results, stream power was suggested as an indicator to estimate soil detachment rate instead of shear stress in soil erosion models. However, considering the simplicity and availability, power
  • function of flow depth and slope gradient is also recommended to predict detachment rate on the road surfaces.
  • 2009
  • Reduced-complexity flow routing models for sinuous single-thread channels : intercomparison with a physically-based shallow-water equation model
  • Braided channel ; Carrying capacity ; Channel geometry ; Comparative study ; Model ; Sediment transport ; Slope gradient ; Stream ; Stream flow
  • water equations. This comparison provides the first demonstration of the potential for deriving realistic predictions of in-channel flow depth, unit discharge, energy slope and unit stream power using simple flow routing schemes. It also highlights
  • This study presents two new reduced-complexity flow routing schemes developed specifically for application in single-thread rivers. Output from both schemes is compared with that from a more sophisticated model that solves the depth-averaged shallow
  • the inadequacy of modelling unit stream power, shear stress or sediment transport capacity as a function of local bed slope, as has been common practice in a number of previous reduced-complexity models.
  • 2009
  • Spatial and temporal patterns of stream channel incision in the loess region of the Missouri River
  • Base level ; Downcutting ; Fluvial erosion ; Fluvial processes ; Hydraulic works ; Iowa ; Loess ; Missouri ; Model ; Nebraska ; Spatial variation ; Stream ; United States of America ; Watershed
  • on tributaries is demonstrated to follow a simple rule of base-level lowering at the outlet multiplied by a flow-length ratio. This rule is used to estimate depth of channel incision along all tributary streams of the Nebraska reach of the Missouri River
  • and confirms that Missouri River degradation, along with other local disturbances such as channelization, is an important cause of tributary stream incision in the study area. Using the flow-length ratio rule, a spatial model of stream channel incision
  • Stream channel incision is severe in the loess-dominated region of western Iowa and eastern Nebraska, with recent incision related to sediment capture by reservoirs on the Missouri River. This study confirms that the temporal pattern of incision
  • follows the rate law proposed by Graf (1977) with half-lives ranging from two to nine years and stream channels throughout the affected watersheds approaching a new dynamic equilibrium in one to three decades. The resulting spatial pattern of incision
  • 2009
  • Flow energy and channel adjustments in rills developed in loamy sand and sandy loam soils
  • of links between rill configuration and flow energy. On a loamy sand, adjustment towards equilibrium occured due to channel widening and meandering, whereas on a sandy loam, mobile knickpoints and chutes, pulsations in flow width and flow depth and changes
  • in stream power and sediment discharge occurred as the channel adjusted towards equilibrium. The tendency of rill systems towards quasi-stability is shown by changes in stream power values which show short-lived minima. The study confirmed that energy
  • dissipation increased with flow aspect ratio. In stabilized rills, flow acceleration reduced energy dissipation on the loamy sand but not on the sandy loam. On both soils flow deceleration tended to increase energy dissipation. Understanding how rill systems
  • 2009
  • Carrying capacity ; Colorado ; Discharge ; Grain size distribution ; Longitudinal section ; River bed ; Sediment load ; Stream ; Stream flow ; Tracer ; Turbulence ; United States of America
  • instantaneous velocities and turbulence levels in the centre of pools. Patterns of sediment deposition support the notion that stream competence is higher in the pool than the downstream riffle. Flow convergence around a large channel constriction appears
  • Three-dimensional velocities and turbulence intensities were measured with an acoustic Doppler velocimeter at 222 different points at 3 similar flows within a large pool-riffle unit on North Saint Vrain Creek, Colorado. Sediment-sorting patterns
  • were observed with the introduction of 500 tracer particles painted according to initial seeding location. Tracer particles moved sporadically during a 113 day period in response to the annual snowmelt peak flow. Velocity data indicate high
  • to play a major role in multiple processes. Jet flow, flow separation, vortex scour and turbulence generation enhance scour in the centre of pools. Ultimately, multiple processes appear to play some role in maintenance of this forced pool
  • 2009
  • Planform dynamics of braided streams
  • Applied geomorphology ; Braided channel ; Discharge ; Earth surface processes ; Experimentation ; Italy ; Model ; Stream ; Trentino-Alto Adige
  • This work is aimed at the characterization of the morphology of braided streams, in order to assess whether the system reaches a steady state under constant flow conditions and, in that case, to determine how it can be described and on which
  • , related to total water discharge and stream power. The paper ends with a discussion on different width definitions and on the relationship between width and discharge, that distinctively characterize the braided pattern.
  • 2009
  • Biodiversity ; Concept ; Eastern Cape ; Ecosystem ; Habitat ; Hydraulic works ; River regime ; South Africa ; Stream ; Stream flow ; Sustainable development ; Water quality ; Water resources
  • This paper suggests methods for the sustainable operation of water resource use and protection. Environmental flows (EF) for rivers are used to illustrate some of the opportunities and problems inherent in managing rivers sustainably. In particular
  • , there is a requirement for agreeing on clear and measurable environmental objectives for which a modified flow regime can be set. Knowledge from a number of different disciplines, including hydrology, ecology, hydraulics, geomorphology, water quality and socio-economics
  • 2009
  • Channel degradation and slope adjustment in steep streams controlled through bed sills
  • Catalonia ; Channel geometry ; Degradation ; Downcutting ; Ephemeral stream ; Hydraulic works ; Longitudinal section ; River bed ; Spain ; Stream ; Urban area ; Urban growth
  • with sills than without sills under the same flow and sediment rates. The equations for the calculation of equilibrium slopes, scaled to ptototype, are applied to the case-study, with good agreement.
  • 2009
  • Wood distribution in neotropical forested headwater streams of La Selva, Costa Rica
  • Bank erosion ; Carrying capacity ; Costa Rica ; Discharge ; Model ; Multiple regression ; Spatial distribution ; Statistics ; Stream ; Tropical zone ; Woody debris
  • . The variables wood diameter/flow depth, stream power, the presence of backflooding, and channel width/depth are consistently selected as significant predictors by statistical models for wood load. The results along with the spatial distribution of wood
  • The aim of this study is to use data data on wood loads from headwater streams in La Selva Biological Station in north-eastern Costa Rica to examine potential differences in wood dynamics between temperate and tropical headwater streams
  • 2009
  • Carrying capacity ; Confluent ; Cross section ; Grain size distribution ; Human impact ; Hydrodynamics ; India ; Maharashtra ; Sedimentology ; Stream ; Stream flow
  • particles were recorded. Sediment characteristics between tributary and the main stream reflect both downstream distance from sediment source and the characteristics of the respective transport processes. The distribution of fine material at the tributary
  • mouth suggests that there have been instances in the past where the mainstream flow has dominated the confluence and has led to slack water deposits on the tributary mouth. In this large seasonal river, confluence sedimentology is a joint product of flow
  • 2009
  • Seepage erosion in layered stream bank material
  • Bank erosion ; Experimentation ; North Carolina ; Slope gradient ; Soil properties ; Stream ; Underground water ; United States of America
  • This paper describes seepage flows, soil moisture conditions, and failure mechanisms for 3 laboratory experiments on reconstructed eastern North Carolina streambanks with layered soils subject to lateral seepage. The observed failure mechanisms
  • 2009
  • Longitudinal distributions of river flood power : the combined automated flood, elevation and stream power (CAFES) methodology
  • Digital elevation model ; Discharge ; England ; Geographical information system ; Methodology ; Sediment transport ; South-West England ; Stream ; Stream flow ; United Kingdom ; Watershed
  • The AA. present here a novel methodology CAFES (combined automated flood, elevation and stream power) to quantify downstream change in river flood power, based on integrating in a GIS framework Flood Estimation Handbook systems with the 5 m grid
  • 2009
  • Modelling hyperconcentrated flow in the Yellow River
  • Carrying capacity ; China ; Flood ; Fluvial erosion ; Huang He ; Model ; Numerical model ; Sediment transport ; Sedimentation ; Stream ; Stream flow
  • 2009
  • Channel geometry ; China ; Concept ; Discharge ; Ecosystem ; Habitat ; Huang He ; Hydraulic works ; River bed ; River regime ; Stream ; Stream flow ; Sustainable development ; Water quality
  • the standards adopted should be adjusted according to the change of the given conditions. The key factor of river health is the enough and clean flow. The AA. stressed that human activities would hurt the river health which include excessive water diversion
  • , riverbed morphology, water quality etc. Taking the Yellow River as a case, this paper also discussed the method to identify what are the standards of a healthy river as well as environmental flows.
  • 2009
  • technology allows such long-term coastal zone change to be visualised and documented, and, to some extent, quantified. Explanations for this change relate primarily to altered stream flow regimes : after the development of the Snowy Mountains Hydro
  • -electricity Scheme (SMHS) from 1951, which currently appropriates the vast majority of annual discharge from the high rainfall and snowfall areas of the upper Snowy River catchment. Whilst ebb-flow augmentation via stream flow discharge is essential
  • 2009
  • Cameroon ; Climatic variability ; Discharge ; Drought ; Sediment transport ; Stream ; Stream flow ; Suspended load
  • 2009
  • Carrying capacity ; Cluster analysis ; Forecast ; Gravel ; Microstructure ; Mountain ; Sediment load ; Statistics ; Stream ; United States of America ; Washington State
  • The occurence of cluster microforms in natural rivers is examined using data collected from 3 mountain streams. A statistical analysis using logistic regression was performed to examine the correlation between the occurence of clusters and various
  • in cobble-size sediment within depositional mountain reaches, for which the majority of the sediment can become mobilized by yearly peak flows.
  • 2009
  • Arkhangelsk ; Climatic change ; Dynamic model ; European part of Russia ; Forest ; Meteorology ; River basin ; Stochastic model ; Stream ; Stream flow ; Water regime
  • 2009
  • Bank erosion ; Discharge ; Italy ; Mass movement ; Model ; Numerical model ; Stream ; Toscana
  • flow events occurred during the period of investigation, with the largest having an estimated return period of about 1.5 years. Bank simulations were performed by linking hydrodynamic, fluvial erosion, groundwater flow and bank stability models
  • , for the 7 flow events, which are representative of the typical range of hydrographs that normally occur during an annual cycle. As a result fluvial erosion is ineffective at higher peak discharges, and depends more on the duration of more moderate discharges
  • typically occur in the late phase of the flow hydrograph, when they may be induced by the cumulative effects of any fluvial erosion.
  • 2009