scholarly journals Debris‐flow‐dominated sediment transport through a channel network after wildfire

2020 ◽  
Vol 45 (5) ◽  
pp. 1155-1167
Author(s):  
Petter Nyman ◽  
Walter A.C. Box ◽  
Justin C. Stout ◽  
Gary J. Sheridan ◽  
Saskia D. Keesstra ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Debris Flow ◽  
Channel Network

Post Wildfire Debris Flow and Flood Analysis of the September 2020 Badger Fire in the Trapper Creek and Rock Creek Watersheds, Idaho, USA.

2021 ◽  
Author(s):  
Stephen Turnbull ◽  
Nawa Pradhan ◽  
Ian Floyd
Keyword(s):  
Debris Flow ◽  
Finite Volume ◽  
Overland Flow ◽  
Frozen Ground ◽  
Channel Network ◽  
Hydrologic Analysis ◽  
Flood Analysis ◽  
Model Equations ◽  
Volume Method ◽  
Parameter Values

<p>There are several different infiltration, overland flow routing, and channel routing schemes that can be used in conjunction with recommended hydrodynamic and infiltration parameter values, which are found within the literature, to provide critical flooding assessments for stakeholders and decision makers.  We focus on post wildfire debris flow and flood analysis in two tributaries of the Snake River in Idaho, Trapper Creek and Rock Creek.  The Badger Fire started on September 12, 2020 in the Sawtooth National Forest in Idaho, USA, and burned sub-alpine fir, lodgepole pine, juniper, mountain brush and grass communities, in the upper part of both the Trapper Creek and Rock Creek watersheds.  Trapper Creek has a U.S. Geological Gaging station, and there are two snow gaging sites available.   The biggest concern for flooding and debris flow is the result of a wintertime rain-on-snow event, which resulted in the largest storm in the gaging record period.    </p><p>To estimate runoff in ungaged stream locations, existing process-based hydrodynamic models can be applied in a distributed form to solve the governing equations for mass, momentum and energy in a spatially explicit way. The purpose of this study is to predict potentially inundated land areas as a result of a rain-on-snow event, using the data in the gages basin to provide flood analysis information for both the gaged (Trapper Creek) and ungaged watershed (Rock Creek).  Rain-on-snow events are rainfall events that occur on the snowpack and frozen ground, resulting in a larger magnitude and volume of streamflow.  To predict these flows, Gridded Surface Subsurface Hydrologic Analysis (GSSHA) watershed models are prepared and calibrated to simulate rain-on-snow events in both watersheds.  The runoff generated from a two dimensional overland flow grid is transferred over land with a finite volume numerical method into a one dimensional channel network.  The channel network also uses a finite volume method.    The consistency in the identified range of the parametric values and their physical applicability make GSSHA an ideal candidate for this study, as the model equations provide a methods to evaluate a rain-on-snow event.</p>

Debris flow initiation from ravel-filled channel bed failure following wildfire in a bedrock landscape with limited sediment supply

2021 ◽  
Author(s):  
Marisa C. Palucis ◽  
Thomas P. Ulizio ◽  
Michael P. Lamb
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Sediment Supply ◽  
Moderate Intensity ◽  
Sandy Sediment ◽  
Channel Network ◽  
Sediment Yields ◽  
First Order ◽  
Dry Ravel ◽  
Debris Flow Initiation

Steep, rocky landscapes often produce large sediment yields and debris flows following wildfire. Debris flows can initiate from landsliding or rilling in soil-mantled portions of the landscape, but there have been few direct observations of debris flow initiation in steep, rocky portions of the landscape that lack a thick, continuous soil mantle. We monitored a steep, first-order catchment that burned in the San Gabriel Mountains, California, USA. Following fire, but prior to rainfall, much of the hillslope soil mantle was removed by dry ravel, exposing bedrock and depositing ∼0.5 m of sandy sediment in the channel network. During a one-year recurrence rainstorm, debris flows initiated in the channel network, evacuating the accumulated dry ravel and underlying cobble bed, and scouring the channel to bedrock. The channel abuts a plowed terrace, which allowed a complete sediment budget, confirming that ∼95% of sediment deposited in a debris flow fan matched that evacuated from the channel, with a minor rainfall-driven hillslope contribution. Subsequent larger storms produced debris flows in higher-order channels but not in the first-order channel because of a sediment supply limitation. These observations are consistent with a model for post-fire ravel routing in steep, rocky landscapes where sediment was sourced by incineration of vegetation dams—following ∼30 years of hillslope soil production since the last fire—and transported downslope by dry processes, leading to a hillslope sediment-supply limitation and infilling of low-order channels with relatively fine sediment. Our observations of debris flow initiation are consistent with failure of the channel bed alluvium due to grain size reduction from dry ravel deposits that allowed high Shields numbers and mass failure even for moderate intensity rainstorms.

Multiple Model Analysis of Sediment Transport and Contaminant Distribution in the Clinch River/Watts Bar Reservoir, Tennessee, USA*

1993 ◽  
Vol 28 (8-9) ◽  
pp. 65-78 ◽  
Author(s):  
K. A. Rose ◽  
A. L. Brenkert ◽  
G. A. Schohl ◽  
Y. Onishi ◽  
J. S. Hayworth ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Data Collection ◽  
Multiple Model ◽  
Channel Network ◽  
Common Information ◽  
Calibration Methods ◽  
Future Data ◽  
Spatial Geometry ◽  
Clinch River ◽  
Contaminant Distribution

Three models of sediment transport and contaminant distribution (CHARIMA, HEC-6, and TODAM) are being applied to the Clinch River/Watts Bar Reservoir system as part of a CERCLA remedial investigation. Planned uses of model results are to identify high deposition areas of the river, forecast the effects of various remedial actions and climatic events on contaminant distribution, and aid in the design of future data collection efforts. The three models share some similarities but also differ in several important details. All three models are one-dimensional and include similar processes for sediment deposition and resuspension. Differences among the models include steady-state versus unsteady flow, the complexity of the channel network permitted, and the level of detail of contaminant-related fate processes represented. As part of our multiple model strategy, some aspects of the three models are configured using common information on the system (e.g., spatial geometry), while other aspects of the models, including some modeler decisions and calibration methods, are allowed to differ. Comparison of results among the three models can lead to increased confidence in predictions and in recommendations for future data collection. The general approach of using multiple models is described and preliminary results of the Clinch River/Watts Bar application are presented to illustrate the utility of using a multiple model approach for complex environmental assessments.

Sediment Production in a small Appalachian Watershed during Spring Runoff: The Eaton Basin, 1970–1972

1973 ◽  
Vol 10 (12) ◽  
pp. 1707-1734 ◽  
Author(s):  
M. A. Carson ◽  
C. H. Taylor ◽  
B. J. Grey
Keyword(s):  
United States ◽  
Sediment Transport ◽  
The United States ◽  
Channel Network ◽  
Discharge Data ◽  
Sediment Rating Curve ◽  
Sediment Yields ◽  
Sediment Production ◽  
Spring Runoff

This report describes work in an IHD Representative Basin in the Quebec Appalachians, the Eaton River Basin (86 km2 in area), upstream from Randboro. The Basin is dominantly forest-covered, contains no large settlement, and, in general, shows little human disturbance that might affect sediment production. The suspended load of the Eaton River was studied in detail during the spring runoff periods of 1970 and 1971; available long-term discharge data indicate these to be representative of present-day conditions. Sediment transport rates are well below capacity and sediment yields are lower than might have been expected from the Langbein-Schumm data in the United States. Suspended sediment originates primarily from scour of the banks of the channel network, and concentrations show a systematic increase with basin area (or distance downstream), quite unlike previous data from the midwestern United States. The sediment rating curve approach is a very good predictor of sediment transport rates, although because of the differences in hydrograph type, there is a large difference between the equations for the 1970 and 1971 spring floods. This difference, and residuals from the sediment rating curves, are considered in a simulation model of sediment production from bank erosion based on the changing shear resistance of bank sediment during a fluctuating hydrograph.

Mixed sediment transport in a stratified estuary: first insights from a field study

2021 ◽  
Author(s):  
Iris Niesten ◽  
Ton Hoitink ◽  
Bart Vermeulen ◽  
Ymkje Huismans
Keyword(s):  
Sediment Transport ◽  
Water Column ◽  
Suspended Sediment ◽  
Lower Layer ◽  
Sediment Type ◽  
Sediment Characteristics ◽  
Channel Network ◽  
Flow Measurements ◽  
Gravitational Circulation ◽  
Port Area

<p>Many estuaries are characterized by a mixture of clay, silt and sand. The erosion, (re-)suspension and transport of these sediments determine the bathymetry and stability of an estuary. Net estuarine sediment transport is the result of multiple processes. In stratified estuaries, gravitational circulation may lead to an inland near-bed sediment transport, which is directed opposite to the net sediment transport higher in the water column. Considering that coarse material is often transported near the bed, while suspended sediment usually consists of finer particles, gravitational circulation may cause a seaward flux of fine sediment and a landward flux of coarse sediment. The New Waterway in the Rotterdam Port area (The Netherlands) is such a stratified channel. Repeated channel deepening has intensified stratification, resulting in a strong salt-wedge type of flow. The channel is continuously dredged for navigation purposes, while the channel would naturally be gaining sediment (Cox et al., 2020). The amount of sediment entering the channel from sea and upstream, and the contribution of different sediment fractions however remain unclear. In this research, we combine  data analysis with numerical modelling to better understand and quantify sediment transport in stratified estuarine channels.</p><p>As a first step, we set up a field campaign which combines flow measurements with determination of suspended sediment characteristics. A measurement frame is equipped with a Sequoia LISST-200x and an YSI EXO Turbidity meter. Suspended sediment characteristics are determined every hour at three depths, next to water temperature, salinity and turbidity. Water samples are taken simultaneously to determine suspended sediment concentration, and flow is monitored continuously using a vessel-mounted ADCP. The full campaign includes two 13-hour measurements and covers two locations in the New Waterway.</p><p>The flow in the upper layer of the water column shows to be decoupled from the saline layer below. Before the flood acceleration phase, the upper and lower layer show an opposite flow direction, corresponding to the findings of De Nijs et al. (2010). The LISST-measurements confirm that suspended sediment in the upper water layer contains a high amount of clay and silt, while the material close to the bed is predominantly sand. This suggests a correlation between grain size and net transport direction. It should be noted that a major part of suspended sediment seems to be transported in the saline bottom layer, and that near-bed processes and local sediment availability could play an important role in the net sediment transport. Continued measurements and the modelling study will further reveal the sensitivity of the net sediment transport to sediment type, and provide insight in the effect of channel deepening.</p><p> </p><p>Cox, J.R., Y. Huismans, J.F.R.W. Leuven, N.E. Vellinga, M. Van der Vegt, A.J.F. Hoitink, and M.G. Kleinhans (2020). “Anthropogenic effects on the Contemporary Sediment Budget of the Lower Rhine-Meuse Delta Channel Network.” Manuscript submitted to Earths Future.</p><p>Nijs, Michel A. J. de, Johan C. Winterwerp, and Julie D. Pietrzak (2010). “The Effects of the Internal Flow Structure on SPM Entrapment in the Rotterdam Waterway.” Journal of Physical Oceanography 40, no. 11: 2357–80.</p>

Sedimentation associated with glaciovolcanism: a review

2022 ◽  
pp. SP520-2021-135
Author(s):  
J. L. Smellie
Keyword(s):  
Heat Flux ◽  
Sediment Transport ◽  
Debris Flow ◽  
Hot Spots ◽  
Explosive Eruptions ◽  
Geothermal Heat ◽  
Sedimentary Deposits ◽  
Depositional Processes ◽  
Dome Collapse ◽  
Subglacial Meltwater

AbstractThree discrete categories of sedimentary deposits are associated with glaciovolcanism: englacial cavity, jökulhlaup and lahar. Englacial cavity deposits are found in water-filled chambers in the lee of active glaciovolcanoes or at a locus of enhanced geothermal heat flux. The cavities provide a depocentre for the accumulation of debris, either abundant fresh juvenile debris with sparse dropstones (associated with active glaciovolcanism) or polymict basal glacial debris in which dropstones are abundant (associated with geothermal hot spots). Described examples are uncommon. By contrast, volcanogenic jökulhlaup deposits are abundant, mainly in Iceland, where they form extensive sandar sequences associated with ice-covered volcanoes. Jökulhlaups form as a result of the sudden subglacial discharge of stored meltwater. Analogous deposits known as glaciovolcanic sheet-like sequences represent the ultra-proximal lateral equivalents deposited under the ice. Glaciovolcanic lahars are associated with ice-capped volcanoes. They form as a result of explosive eruptions through relatively thin ice or following dome collapse, and they trigger mainly supraglacial rather than subglacial meltwater escape. Sediment transport and depositional processes are similar in jökulhaups and lahars and are dominated by debris flow and hyperconcentrated or supercritical flow modes during the main flood stage, although the proportions of the principal lithofacies are different.

Relationship between sediment connectivity and debris flow in a mountain catchment

2021 ◽  
Author(s):  
Bruno Henrique Abatti ◽  
Franciele Zanandrea ◽  
Leonardo Rodolfo Paul ◽  
Gean Paulo Michel
Keyword(s):  
Sediment Transport ◽  
Debris Flow ◽  
Flow Direction ◽  
Rectangular Channel ◽  
Computational Modelling ◽  
Horizontal Resolution ◽  
Mass Movements ◽  
Channel Coupling ◽  
High Magnitude ◽  
Sediment Connectivity

<p>The hillslope-channel coupling has a fundamental role in sediment control of a catchment, especially when the catchment is prone to mass movements. Debris flow is a type of mass movements that provides an important sediment contribution to a channel, which is influenced by hillslope-channel coupling degree. This coupling can be represented by the connectivity, a concept utilized as an approach to many queries regarding water and/or sediment transport through methodologies which relates a river with its drainage area. In this regard, this study addresses the representation of debris flow in terms of connectivity. We applied a debris flow computational modelling (DFM) and an index of connectivity (IC) in Mascarada catchment, south Brazil, where hundreds of mass movements were triggered in 2017, to evaluate the potential, limitations and capacity of IC to represent patterns of mass movements’ connectivity. The IC is calculated for each cell of the catchment’s digital elevation model (DEM) (horizontal resolution of 1 m) in relation to the drainage network. Therefore, the IC represents the lateral connectivity (hillslope-channel) and its capacity to mobilize sediment to the channel. The DFM utilizes the Multiple Flow Direction to distribute volumes of a fluid with a determined kinematic viscosity through a slope, originated from initiation areas with a depth pre-determined by the user. The model utilizes uniform and steady flow solutions for Newtonian fluid, considering a rectangular channel. The DFM simulated the observed debris flow reasonably well, with an accuracy of 68%. However, since the simulation reached the channel and carried the volumes beyond the observed debris flow scar, it presented an overestimation area of 65%. When relation the simulated debris flow paths with the IC, we observed a superposition between those paths and high IC values. Also, the results showed a pixel-by-pixel positive linear correlation between high flow depths (representing convergence of flow) and IC, with values varying from 0,1 and 0,5. Only one of the nine simulated debris flow did not reach the channel and it had the lowest mean IC value along its flow path. Simulated debris flow that reached the channel showed high hillslope-channel connectivity, denoting the important role of high magnitude sediment transport events in sediment connectivity. Therefore, the IC was capable to represent and indicate patterns of debris flow that reached the channel. Though, the results also indicated that IC must be carefully interpreted when employed to understand debris flow and related processes – some areas have high fluid depth due to low connectivity, but others have high depth in response of convergence of flow due to highly connected areas. In this regard, an integration of connectivity and debris flow modelling tools can by an important step to understand sediment connectivity and to represent patterns of high magnitude mass movements events.</p>

Mathematical modelling of riverbed dynamics – a Canadian case study

1991 ◽  
Vol 18 (5) ◽  
pp. 772-780 ◽  
Author(s):  
B. Morse ◽  
R. D. Townsend ◽  
M. Sydor
Keyword(s):  
Mathematical Model ◽  
Sediment Transport ◽  
Model Simulation ◽  
Fixed Bed ◽  
Channel Network ◽  
Bed Elevation ◽  
Mobile Bed ◽  
Cumulative Change ◽  
Degradation Pattern ◽  
River Training

A new mobile-bed mathematical model for simulating sediment transport in river networks under unsteady flow conditions is presented. The new model, ONE-D-SED, is an extended version of the extensively validated fixed-bed, one-dimensional hydrodynamic model ONE-D. This paper reports the results of an application of ONE-D-SED to simulate bed profile development along a 43-km-long tidal channel network of the Lower Fraser River in British Columbia. The sand-bed study reach has been undergoing degradation caused by navigational dredging and river training works in lower channel reaches and by borrow dredging within the study reach itself, ONE-D-SED was used to simulate bed degradation in the study reach during the 1979–1984 period. The simulated annual change in bed elevation at the downstream end of the study reach showed good agreement with that observed during 1968, the data year used to calibrate the model. The predicted cumulative change in bed profile from 1979 to 1984 also compared favourably with the overall degradation pattern observed during that same period. Key words: mathematical model, simulation, sediment transport, river network, finite difference, model validation.

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