scholarly journals River flow and sediment transport simulation based on a curvilinear and rectilinear grid modelling approach – a comparison study

2017 ◽  
Vol 17 (5) ◽  
pp. 1325-1334 ◽  
Author(s):  
G. G. Morianou ◽  
N. N. Kourgialas ◽  
G. P. Karatzas ◽  
N. P. Nikolaidis
Keyword(s):  
Sediment Transport ◽  
River Flow ◽  
Morphological Changes ◽  
Field Measurements ◽  
Grid Model ◽  
Curvilinear Grid ◽  
Saint Venant Equations ◽  
Flow And Sediment Transport ◽  
Downstream Section ◽  
The Difference

In the present work, a two-dimensional (2D) hydraulic model was used for the simulation of river flow and sediment transport in the downstream section of the Koiliaris River Basin in Crete, Greece, based on two different structured grids. Specifically, an important goal of the present study was the comparison of a curvilinear grid model with a rectilinear grid model. The MIKE 21C model has been developed to simulate 2D flows and morphological changes in rivers by using either an orthogonal curvilinear grid or a rectilinear grid. The MIKE 21C model comprises two parts: (a) the hydrodynamic part that is based on the Saint-Venant equations and (b) the morphological change part for the simulation of bank erosion and sediment transport. The difference between the curvilinear and the rectilinear grid is that the curvilinear grid lines follow the bank lines of the river, providing a better resolution of the flow near the boundaries. The water depth and sediment results obtained from the simulations for the two different grids were compared with field observations and a series of statistical indicators. It was concluded that the curvilinear grid model results were in better agreement with the field measurements.

scholarly journals Application of Python Scripting Techniques for Control and Automation of HEC-RAS Simulations

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1382 ◽  
Author(s):  
Tomasz Dysarz
Keyword(s):  
Sediment Transport ◽  
River Flow ◽  
Data File ◽  
Automatic Calibration ◽  
Sediment Samples ◽  
Python Script ◽  
The Third ◽  
Python Scripting ◽  
Flow And Sediment Transport ◽  
Sediment Data

The purpose of the paper was to present selected techniques for the control of river flow and sediment transport computations with the programming language Python. The base software for modeling of river processes was the well-known and widely used HEC-RAS. The concepts were tested on two models created for a single reach of the Warta river located in the central part of Poland. The ideas described were illustrated with three examples. The first was a basic simulation of a steady flow run from the Python script. The second example presented automatic calibration of model roughness coefficients with Nelder-Mead simplex from the SciPy module. In the third example, the sediment transport was controlled by Python script. Sediment samples were accessed and changed in the sediment data file stored in XML format. The results of the sediment simulation were read from HDF5 files. The presented techniques showed good effectiveness of this approach. The paper compared the developed techniques with other, earlier approaches to control of HEC-RAS computations. Possible further developments were also discussed.

Two dimensional river flow and sediment transport model

2014 ◽  
Vol 15 (3) ◽  
pp. 595-625 ◽  
Author(s):  
Zoltan Horvat ◽  
Mirjana Isic ◽  
Miodrag Spasojevic
Keyword(s):  
Sediment Transport ◽  
River Flow ◽  
Transport Model ◽  
Two Dimensional ◽  
Sediment Transport Model ◽  
Flow And Sediment Transport

scholarly journals Hydrodynamic Condition Modeling along the North-Central Coast of Vietnam

2020 ◽  
Vol 10 (3) ◽  
pp. 5648-5654
Author(s):  
D. D. Cham ◽  
N. T. Son ◽  
N. Q. Minh ◽  
N. T. Hung ◽  
N. Tien Thanh
Keyword(s):  
Sediment Transport ◽  
River Flow ◽  
Morphological Changes ◽  
Main Channel ◽  
Low Flow ◽  
Hydrodynamic Condition ◽  
Central Coast ◽  
North Central ◽  
The North ◽  
Coast Of Vietnam

An extremely dynamic morphology of the estuary is observed in the coastal regions of Vietnam under the governing processes of tides, waves, and river system flows. The primary target of this paper is to provide insight into the governing processes and morphological behavior of the NhatLe estuary, located in the north-central coast of Vietnam. Based on measured data from field surveys and satellite images combined with numerical model simulations of MIKE and Delft3D, the influences of seasonal river flow, tides, and wave dynamics on the sediment transport and morphological changes are fully examined. The study showed that freshwater flow in the flood season plays a central role in cutting off the southern sandspit, maintain and shaping the main channel. The prevailing waves in winter and summer induce longshore drift and sediment transport in the southeast to northwest direction. In the low flow season, this longshore sediment transport is dominant, causing sediment to deposit on the southern side of the ebb tidal delta and elongating the southern sandspit which narrows the estuary entrance and reorients the main channel.

scholarly journals MODELLING OF THE IMPACT OF A WAVE FARM ON NEARSHORE SEDIMENT TRANSPORT

2012 ◽  
Vol 1 (33) ◽  
pp. 66 ◽  
Author(s):  
Raul Gonzalez ◽  
Qingping Zou ◽  
Shunqi Pan
Keyword(s):  
Sediment Transport ◽  
Large Scale ◽  
Morphological Changes ◽  
Field Measurements ◽  
Integrated Modelling ◽  
Shear Stresses ◽  
Nearshore Sediment Transport ◽  
Wave Farm ◽  
The Impact ◽  
Modelling System

This paper presents the results from an integrated modelling system investigating the effects of a wave farm on nearshore sediment transport. Wave Hub project is a large scale demonstration site for the development of the operation of arrays of wave energy generation devices located at the southwest coast of the UK where multiple field measurements took place. The two-way coupled SWAN and ROMS models with nested modelling system were set up at the Wave Hub site and run with and without a wave farm. The model results show that the presence of the wave farm has significant impacts on the nearshore circulation, bed shear stresses and sediment transport. The morphological changes are also altered by the wave farm. The study is the key element for the wave resource characterization and environmental impact assessment of the wave farm.

scholarly journals Suspended sediment transport map for disaster mitigation in the upper course of Jangkok River

2021 ◽  
Vol 331 ◽  
pp. 08005
Author(s):  
Yusron Saadi ◽  
IB Giri Putra ◽  
Agus Suroso
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
River Flow ◽  
Rapid Change ◽  
Field Measurements ◽  
Sediment Concentration ◽  
Disaster Mitigation ◽  
Suspended Sediment Transport ◽  
Preventive Action ◽  
Two Parameters

Jangkok River, a very important river for irrigation purposes in Lombok Island Indonesia is experiencing a rapid change in the land use of its watershed. The conversion of trees into seasonal crops in the watershed causes a decrease in the carrying capacity of the watershed and reduces its ability to prevent soil erosion. Environmental damages such as erosion and sedimentation along the river are becoming increasingly difficult to control. This paper proposed an idea to identify river conditions based on suspended sediment concentration. A series of field measurements of suspended sediment concentrations and river flow discharges were carried out to obtain the relationship between these two parameters. A resulting watershed map contains information on the rate of suspended sediment transport in the form of a suspended sediment-flow discharge rating curve is designed as a sediment conservation health indicator of the watershed. The map allows the authority to observe the condition of each river order in the upper course of the Jangkok River since the nearby tributaries are most likely to have their pattern of suspended sediment transport rate. The finding from this preliminary study can facilitate the drafting and implementation of the right policy in watershed conservation management planning which leads to preventive action and better preparedness in disaster mitigation.

scholarly journals Numerical Simulation of Volume Change of the Backshore Induced by Cross-Shore Aeolian Sediment Transport

2020 ◽  
Vol 8 (6) ◽  
pp. 438 ◽  
Author(s):  
Masato Yokobori ◽  
Yoshiaki Kuriyama ◽  
Takenori Shimozono ◽  
Yoshimitsu Tajima
Keyword(s):  
Sediment Transport ◽  
Volume Change ◽  
Morphological Changes ◽  
Model Performance ◽  
Small Scale ◽  
Sediment Size ◽  
Investigation Area ◽  
Cumulative Volume ◽  
The Difference ◽  
Aeolian Sediment

Predicting the morphological changes of the backshore is vital for appropriate beach management because the backshore plays a significant role in the ecosystem and disaster prevention. In this study, a one-dimensional model was developed and applied to the Hasaki Coast in Japan to predict changes in backshore volume. The volume change was estimated from the difference between the aeolian sediment transport rates at the seaward and landward boundaries of the investigation area, considering the wind velocity and direction, sediment size, precipitation, and vegetation in the process. The model was calibrated and validated using the first and second halves of beach profile data obtained weekly at the Hasaki Coast over a 28-year period from 1987 to 2014. The validation suggests that the model can reasonably reproduce the cumulative volume change, which is the amount of volume change from the initial value, but it underestimates the time-varying fluctuations of the weekly averaged volume-change rate. This can be attributed to the presence of small-scale features, such as dense vegetation and wrack, which are not taken into account in the model. Although the model performance for the cumulative volume change was good, it overpredicted the values in the second half of the validation process. This can be attributed to the fact that the model is not able to predict reductions in the aeolian sediment transport rate caused by an increase in beach steepness.

scholarly journals Patterns of Difference between Physical and 1-D Calibrated Effective Roughness Parameters in Mountain Rivers

Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3202
Author(s):  
Sebastián Cedillo ◽  
Esteban Sánchez-Cordero ◽  
Luis Timbe ◽  
Esteban Samaniego ◽  
Andrés Alvarado
Keyword(s):  
Cross Sections ◽  
River Flow ◽  
Selection Process ◽  
Roughness Parameter ◽  
Field Measurements ◽  
Accurate Estimation ◽  
Roughness Coefficient ◽  
Mountain Rivers ◽  
Effective Roughness ◽  
The Difference

Due to the presence of boulders and different morphologies, mountain rivers contain various resistance sources. To correctly simulate river flow using 1-D hydrodynamic models, an accurate estimation of the flow resistance is required. In this article, a comparison between the physical roughness parameter (PRP) and effective roughness coefficient (ERC) is presented for three of the most typical morphological configurations in mountain rivers: cascade, step-pool, and plane-bed. The PRP and its variation were obtained through multiple measurements of field variables and an uncertainty analysis, while the ERC range was derived with a GLUE procedure implemented in HEC-RAS, a 1-D hydrodynamic model. In the GLUE experiments, two modes of the Representative Friction Slope Method (RFSM) between two cross-sections were tested, including the variation in the roughness parameter. The results revealed that the RFSM effect was limited to low flows in cascade and step-pool. Moreover, when HEC-RAS selected the RSFM, only acceptable results were presented for plane-bed. The difference between ERC and PRP depended on the flow magnitude and the morphology, and as shown in this study, when the flow increased, the ERC and PRP ranges approached each other and even overlapped in cascade and step-pool. This research aimed to improve the roughness value selection process in a 1-D model given the importance of this parameter in the predictability of the results. In addition, a comparison was presented between the results obtained with the numerical model and the values calculated with the field measurements

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