scholarly journals Modeling and Practice of Erosion and Sediment Transport under Change

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1665 ◽  
Author(s):  
Hafzullah Aksoy ◽  
Gil Mahe ◽  
Mohamed Meddi
Keyword(s):  
Sediment Transport ◽  
Rainfall Intensity ◽  
Transport Model ◽  
Anthropogenic Activities ◽  
Rainfall Variability ◽  
Relevant Literature ◽  
Transport Processes ◽  
Rainfall Erosivity ◽  
Special Issue ◽  
Great Portion

Climate and anthropogenic changes impact on the erosion and sediment transport processes in rivers. Rainfall variability and, in many places, the increase of rainfall intensity have a direct impact on rainfall erosivity. Increasing changes in demography have led to the acceleration of land cover changes from natural areas to cultivated areas, and then from degraded areas to desertification. Such areas, under the effect of anthropogenic activities, are more sensitive to erosion, and are therefore prone to erosion. On the other hand, with an increase in the number of dams in watersheds, a great portion of sediment fluxes is trapped in the reservoirs, which do not reach the sea in the same amount nor at the same quality, and thus have consequences for coastal geomorphodynamics. The Special Issue “Modeling and Practice of Erosion and Sediment Transport under Change” is focused on a number of keywords: erosion and sediment transport, model and practice, and change. The keywords are briefly discussed with respect to the relevant literature. The papers in this Special Issue address observations and models based on laboratory and field data, allowing researchers to make use of such resources in practice under changing conditions.

scholarly journals Sediment transport modelling in a distributed physically based hydrological catchment model

2010 ◽  
Vol 7 (5) ◽  
pp. 7591-7631 ◽  
Author(s):  
M. Konz ◽  
M. Chiari ◽  
S. Rimkus ◽  
J. M. Turowski ◽  
P. Molnar ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Hydrological Model ◽  
Transport Model ◽  
Water Cycle ◽  
Transport Processes ◽  
Distributed Hydrological Model ◽  
Water Fluxes ◽  
Transport Modelling ◽  
Erosion Processes ◽  
Grid Level

Abstract. Sediment transport and erosion processes in channels are important components of water induced natural hazards in alpine environments. A distributed hydrological model, TOPKAPI, has been developed to support continuous simulations of river bed erosion and deposition processes. The hydrological model simulates all relevant components of the water cycle and non-linear reservoir methods are applied for water fluxes in the soil, on the surface and in the channel. The sediment transport simulations are performed on a sub-grid level, which allows for a better discretization of the channel geometry, whereas water fluxes are calculated on the grid level in order to be CPU efficient. Flow resistance due to macro roughness is considered in the simulation of sediment transport processes. Several transport equations as well as the effects of armour layers on the transport threshold discharge are considered. The advantage of this approach is the integrated simulation of the entire water balance combined with hillslope-channel coupled erosion and transport simulation. The comparison with the modelling tool SETRAC and with LiDAR based reconstructed sediment transport rates demonstrates the reliability of the modelling concept. The modelling method is very fast and of comparable accuracy to the more specialised sediment transport model SETRAC.

Geomorphological dynamics of subhumid mountain badland areas — weathering, hydrological and suspended sediment transport processes: A case study in the Araguás catchment (Central Pyrenees) and implications for altered hydroclimatic regimes

2010 ◽  
Vol 34 (2) ◽  
pp. 123-150 ◽  
Author(s):  
E. Nadal-Romero ◽  
D. Regüés
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Flood Frequency ◽  
Transport Processes ◽  
Point Of View ◽  
Suspended Sediment Transport ◽  
Rainfall Erosivity ◽  
Maximum Rainfall ◽  
Erosion Processes ◽  
Central Pyrenees

This study investigates the geomorphological dynamics of badland areas in the Araguás catchment (0.45 km2) in the Central Pyrenees. The genesis and development of badlands in the Central Pyrenees is favoured by the presence of Eocene marls and a markedly seasonal climate. The Araguás catchment has been monitored since 2004. Analysis of weathering processes and regolith dynamics showed that alternating freeze-thaw and wetting-drying cycles are the main causes of regolith development and weathering, and effectiveness and intensity of these processes is maximum in winter and summer. Evolution of the badland surfaces is related to regolith moisture level and temperature, closely associated with the season and slope exposure, which cause cyclical variations in regolith physical conditions. The most important effect associated with regolith dynamics is the temporal delay between maximum rainfall erosivity and variation in maximum surface runoff generation, reflected in seasonal differences in sediment transport. The dynamics of weathering and erosion processes affecting badland areas are the principal factors controlling geomorphological development, and the extreme hydrological and sedimentological responses of badlands are the main effects of such morphologies. From a hydrological point of view, badlands increase water production, and flood frequency relative to neighbouring areas; from a sedimentological point of view, suspended sediment transport from badland areas can reach amounts two or three orders of magnitude higher than other nearby environments. Given these results, possible responses of badland dynamics to altered hydroclimatic regime are briefly discussed.

Simulation of Suspended Sediment Transport in a Tidal River

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1421-1430 ◽  
Author(s):  
T. Kusuda ◽  
T. Futawatari
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Transport Model ◽  
Transport Processes ◽  
Tidal River ◽  
Numerical Dispersion ◽  
Suspended Sediment Transport ◽  
Fluid Mud ◽  
River Modeling

Based on the results of field observation in a tidal river, modeling of sediment transport processes is performed and the suspended sediment transport over a long term is simulated with a newly developed procedure, in which the Lagrangian reference frame is used in order to reduce numerical dispersion. The suspended sediment transport in the tidal river is calculated with erosion and deposition of sediments, consolidation of fluid mud to bed mud, and transport by turbidity current. Sediment transport processes concerned with formation and maintenance of turbidity maxima are sufficiently simulated for a fortnightly cycle with the Lagrangian sediment transport model (LSTM).

scholarly journals MODELING ESTUARIAL COHESIVE SEDIMENT TRANSPORT

1984 ◽  
Vol 1 (19) ◽  
pp. 199
Author(s):  
E.J. Hayter ◽  
A.J. Mehta
Keyword(s):  
Sediment Transport ◽  
Transport Model ◽  
Cohesive Sediment ◽  
Transport Processes ◽  
Weighted Residual Method ◽  
Dispersive Transport ◽  
Time Step ◽  
Advection Dispersion ◽  
Cohesive Sediment Transport ◽  
Suspended Sediment Concentrations

Cohesive sediment related problems in estuaries include shoaling in navigable waterways and water pollution. A two-dimensional, depth averaged, finite element cohesive sediment transport model, CSTM-H, has been developed and may be used to assist in predicting the fate of sorbed pollutants and the frequency and quantity of dredging required to maintain navigable depths. Algorithms which describe the transport processes of redispersion, resuspenslon, dispersive transport, settling, deposition, bed formation and bed consolidation are incorporated in CSTM-H. The Galerkin weighted residual method is used to solve the advection-dispersion equation with appropriate source/sink terms at each time step for the nodal suspended sediment concentrations. The model yields stable and converging solutions. Verification was carried out against a series of erosion-deposition experiments in the laboratory using kaolinite and a natural mud as sediment. A model application under prototype conditions is described.

scholarly journals Impacts of Filled Check Dams with Different Deployment Strategies on the Flood and Sediment Transport Processes in a Loess Plateau Catchment

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1319 ◽  
Author(s):  
Honglei Tang ◽  
Hailong Pan ◽  
Qihua Ran
Keyword(s):  
Sediment Transport ◽  
Loess Plateau ◽  
Transport Model ◽  
Transport Processes ◽  
Peak Time ◽  
Engineering Structures ◽  
Sediment Control ◽  
Flood Peak ◽  
Check Dams ◽  
Channel Reduction

As one of the most widespread engineering structures for conserving water and soil, check dams have significantly modified the local landform and hydrologic responses. However, the influences of sedimentary lands caused by filled up check dams on the runoff and sediment transport processes were seldom studied. Employing an integrated hydrologic-response and sediment transport model, this study investigated the influences of filled check dams with different deployment strategies in a Loess Plateau catchment. Six hypothetical deployment strategies of check dams were compared with no-dam scenario and the reality scenario. Results showed that filled check dams were still able to reduce Flood peak (Qp) by 31% to 93% under different deployment strategies. Considerable delays of peak time and decreases were also found in scenarios, which were characterized as having larger and more connective sedimentary lands on the main channel. Reduction rates of Sediment yield (SY) and the total mass of Eroded sediment (ES) ranged from 4% to 52% and 2% to 16%, respectively, indicating that proper distributions of check dams can promote sediment deposition in the channel and reduce soil erosion. The results of this study indicate that (1) check dam systems could still be useful in flood attenuation and sediment control even when they were filled, and (2) optimizing the deployment strategies of check dams can help reduce erosion.

scholarly journals Aeolian Sediment Transport Integration in General Stratigraphic Forward Modeling

2011 ◽  
Vol 2011 ◽  
pp. 1-12
Author(s):  
T. Salles ◽  
C. Griffiths ◽  
C. Dyt
Keyword(s):  
Sediment Transport ◽  
Numerical Model ◽  
Transport Model ◽  
Numerical Models ◽  
Three Dimensional ◽  
Transport Processes ◽  
Aeolian Deposits ◽  
Geological Processes ◽  
Wide Range ◽  
Mixed Soils

A large number of numerical models have been developed to simulate the physical processes involved in saltation, and, recently to investigate the interaction between soil vegetation cover and aeolian transport. These models are generally constrained to saltation of monodisperse particles while natural saltation occurs over mixed soils. We present a three-dimensional numerical model of steady-state saltation that can simulate aeolian erosion, transport and deposition for unvegetated mixed soils. Our model simulates the motion of saltating particles using a cellular automata algorithm. A simple set of rules is used and takes into account an erosion formula, a transport model, a wind exposition function, and an avalanching process. The model is coupled to the stratigraphic forward model Sedsim that accounts for a larger number of geological processes. The numerical model predicts a wide range of typical dune shapes, which have qualitative correspondence to real systems. The model reproduces the internal structure and composition of the resulting aeolian deposits. It shows the complex formation of dune systems with cross-bedding strata development, bounding surfaces overlaid by fine sediment and inverse grading deposits. We aim to use it to simulate the complex interactions between different sediment transport processes and their resulting geological morphologies.

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