Analysis of One-Dimensional Modelling for Flood Routing in Compound Channels

2011 ◽  
Vol 26 (5) ◽  
pp. 1065-1087 ◽  
Author(s):  
Pierfranco Costabile ◽  
Francesco Macchione
Keyword(s):  
Flood Routing ◽  
Compound Channels ◽  
One Dimensional

scholarly journals Comparison of numerical schemes of river flood routing with an inertial approximation of the Saint Venant equations

RBRH ◽  
2018 ◽  
Vol 23 (0) ◽  
Author(s):  
Alice César Fassoni-Andrade ◽  
Fernando Mainardi Fan ◽  
Walter Collischonn ◽  
Artur César Fassoni ◽  
Rodrigo Cauduro Dias de Paiva
Keyword(s):  
Numerical Stability ◽  
Flood Routing ◽  
Computational Time ◽  
Numerical Schemes ◽  
Time Step ◽  
Simple Formulation ◽  
One Dimensional ◽  
Saint Venant Equations ◽  
Original Scheme ◽  
The One

ABSTRACT The one-dimensional flow routing inertial model, formulated as an explicit solution, has advantages over other explicit models used in hydrological models that simplify the Saint-Venant equations. The main advantage is a simple formulation with good results. However, the inertial model is restricted to a small time step to avoid numerical instability. This paper proposes six numerical schemes that modify the one-dimensional inertial model in order to increase the numerical stability of the solution. The proposed numerical schemes were compared to the original scheme in four situations of river’s slope (normal, low, high and very high) and in two situations where the river is subject to downstream effects (dam backwater and tides). The results are discussed in terms of stability, peak flow, processing time, volume conservation error and RMSE (Root Mean Square Error). In general, the schemes showed improvement relative to each type of application. In particular, the numerical scheme here called Prog Q(k+1)xQ(k+1) stood out presenting advantages with greater numerical stability in relation to the original scheme. However, this scheme was not successful in the tide simulation situation. In addition, it was observed that the inclusion of the hydraulic radius calculation without simplification in the numerical schemes improved the results without increasing the computational time.

scholarly journals HYDRODYNAMIC MODELLING OF THE SOUTHERN NORTH SEA

1978 ◽  
Vol 1 (16) ◽  
pp. 65
Author(s):  
David Prandle
Keyword(s):  
North Sea ◽  
Three Dimensional ◽  
Flood Routing ◽  
Hydrodynamic Modelling ◽  
One Dimensional ◽  
Southern North Sea ◽  
Tidal Propagation ◽  
Modelling Studies ◽  
Residual Flows ◽  
Shallow Seas

Numerical modelling of rivers, estuaries and shallow seas has attracted increasing interest over the last two decades. The models have developed from one dimensional (ID) applications to tidal propagation and flood routing through two and, finally, three dimensional applications to motions ranging from "pseudo-turbulence" to annual mean residual flows. The present account describes the development, over the last five years, of the modelling studies carried out by the author concerning the hydrodynamics of the southern North Sea and River Thames. The objective is to identify those major points which have emerged that may have a wider significance.

A comparison of one-dimensional methods for estimating discharge capacity of straight compound channels

2004 ◽  
Vol 31 (4) ◽  
pp. 619-631 ◽  
Author(s):  
Galip Seckin
Keyword(s):  
Discharge Capacity ◽  
Single Channel ◽  
Scale Effects ◽  
Compound Channels ◽  
One Dimensional ◽  
Mobile Bed ◽  
Series Of Experiments ◽  
And Performance ◽  
Discharge Estimation ◽  
Fixed Boundaries

A series of experiments was carried out in a two-stage flume having a smooth main channel and smooth or rough floodplains to investigate the reliability and performance of four different one-dimensional methods for computing the discharge capacity of compound channels, namely, the single-channel method (SCM), the divided-channel method (DCM), the exchange discharge method (EDM), and the Ackers method (AM). Additional data from fixed- and mobile-bed compound laboratory channels with smooth and roughened floodplains and of a prototype compound river channel were also used in the computations. The boundary roughness and scale effects associated with the performance of the four methods are also examined. The results show that the EDM and the AM are able to simulate the measured discharge values more accurately than those of the traditional methods, namely, the DCM and the SCM. Although the error in discharge estimation produced by both the AM and the EDM was generally lower than 10% for both smooth and fixed boundaries, it increased up to 20% for mobile boundaries. Overall, the average relative error in discharge estimations using the AM and the EDM was about 5.4% and 7.1%, respectively, with a standard deviation of 6.7% and 6.8%, respectively. Key words: compound channel flow, stage-discharge relationship, one-dimensional methods.

scholarly journals Interactions between Lake-Level Fluctuations and Waterlogging Disasters around a Large-Scale Shallow Lake: An Empirical Analysis from China

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 318 ◽  
Author(s):  
Zongzhi Wang ◽  
Kun Wang ◽  
Kelin Liu ◽  
Liang Cheng ◽  
Lihui Wang ◽  
...  
Keyword(s):  
Hydrodynamic Model ◽  
Lake Level ◽  
Large Scale ◽  
Drainage System ◽  
Flood Routing ◽  
Lake Basin ◽  
Rainfall Events ◽  
One Dimensional ◽  
Lake Level Fluctuations ◽  
Pumping Stations

Waterlogging disasters in the lakeside areas of shallow lakes that located in plain regions are sensitive to lake-level fluctuations. However, there are very few studies on the influences of lake-level fluctuations on waterlogged lakeside areas from a large lake basin perspective. This paper proposes an integrated hydrodynamic model employing the MIKE software to contribute to the existing literature by filling the gap constituted by the lack of an estimation of the impacts of lake-level fluctuations on waterlogging disasters by relevant models. First, a coupled one-dimensional and two-dimensional hydrodynamic model is established to simulate the waterlogging routing in the lakeside area around Nansi Lake (NL) in addition to the flood routing in NL and its tributaries. Second, the model is calibrated and verified by two measured flood events in July 2007 and July 2008; the results indicate that the model can correctly simulate the drainage process of pumping stations in the lakeside area, as well as the interactions between the waterlogging drainage and lake-level fluctuations. Third, the process of waterlogging in the lakeside area of NL is simulated under different rainfall events and initial lake-level conditions. Fourth, based on the results of the model, this paper illustrates the influences of lake-level fluctuations on the waterlogged area around the lake, as well as the different responses of waterlogging in different areas to lake-level fluctuations in NL and the main cause for these differences. Finally, based on the results of the model, this paper presents some implications for waterlogging simulations and drainage system design.

scholarly journals The Modified One-Dimensional Hydrodynamic Model Based on the Extended Chezy Formula

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1743
Author(s):  
Junwei Zhou ◽  
Weimin Bao ◽  
Yu Li ◽  
Li Cheng ◽  
Muxi Bao
Keyword(s):  
Hydrodynamic Model ◽  
Calibration Method ◽  
Friction Model ◽  
Flood Routing ◽  
Flow Depth ◽  
Parameter Calibration ◽  
Simulation Test ◽  
One Dimensional ◽  
Hydraulic Experiment ◽  
Peak Value

Although steady uniform friction formulas have been introduced to the framework of a one-dimensional (1D) hydrodynamic model for centuries, the error of friction calculation inevitably undermines the performance of flood routing. Based on successful results of unsteady channel friction research studies, a newly proposed unsteady friction model is introduced to establish a modified 1D hydrodynamic model (namely, the modified SVN model). With the help of a carefully designed parameter calibration method, the performance of the modified SVN model was compared with that of the original SVN model in a simulation test for a hydraulic experiment. This study’s results revealed that compared with the original SVN model, the modified SVN model could achieve a better simulation in both the flow depth and the sectional averaged velocity simulations. Furthermore, it could reduce the peak value error and the time-at-peak error as well, indicating that the use of an unsteady friction model can efficiently improve the performance of a 1D hydrodynamic model.

scholarly journals Predicting discharge capacity of vegetated compound channels: uncertainty and identifiability of one-dimensional process-based models

2020 ◽  
Vol 24 (8) ◽  
pp. 4135-4167
Author(s):  
Adam Kiczko ◽  
Kaisa Västilä ◽  
Adam Kozioł ◽  
Janusz Kubrak ◽  
Elżbieta Kubrak ◽  
...  
Keyword(s):  
Discharge Capacity ◽  
Probabilistic Approach ◽  
River Channels ◽  
Compound Channels ◽  
One Dimensional ◽  
Practical Applications ◽  
Rigid Vegetation ◽  
Output Uncertainty ◽  
Hydraulic Conditions ◽  
Flexible Vegetation

Abstract. Despite the development of advanced process-based methods for estimating the discharge capacity of vegetated river channels, most of the practical one-dimensional modeling is based on a relatively simple divided channel method (DCM) with the Manning flow resistance formula. This study is motivated by the need to improve the reliability of modeling in practical applications while acknowledging the limitations on the availability of data on vegetation properties and related parameters required by the process-based methods. We investigate whether the advanced methods can be applied to modeling of vegetated compound channels by identifying the missing characteristics as parameters through the formulation of an inverse problem. Six models of channel discharge capacity are compared in respect of their uncertainty using a probabilistic approach. The model with the lowest estimated uncertainty in explaining differences between computed and observed values is considered the most favorable. Calculations were performed for flume and field settings varying in floodplain vegetation submergence, density, and flexibility, and in hydraulic conditions. The output uncertainty, estimated on the basis of a Bayes approach, was analyzed for a varying number of observation points, demonstrating the significance of the parameter equifinality. The results showed that very reliable predictions with low uncertainties can be obtained for process-based methods with a large number of parameters. The equifinality affects the parameter identification but not the uncertainty of a model. The best performance for sparse, emergent, rigid vegetation was obtained with the Mertens method and for dense, flexible vegetation with a simplified two-layer method, while a generalized two-layer model with a description of the plant flexibility was the most universally applicable to different vegetative conditions. In many cases, the Manning-based DCM performed satisfactorily but could not be reliably extrapolated to higher flows.

A one-dimensional flood routing model for rockfill dams considering exit height

2018 ◽  
Vol 171 (1) ◽  
pp. 42-51 ◽  
Author(s):  
Payam Sarkhosh ◽  
Jamal Mohammad Vali Samani ◽  
Mehdi Mazaheri
Keyword(s):  
Flood Routing ◽  
One Dimensional

scholarly journals Hydrodynamic Study of the Flows Caused by Dam Break around Downstream Obstacles

2018 ◽  
Vol 12 (1) ◽  
pp. 225-238
Author(s):  
Atabak Feizi
Keyword(s):  
Safety Management ◽  
Flow Characteristics ◽  
Experimental Tests ◽  
3D Models ◽  
Dam Break ◽  
Flood Routing ◽  
Accurate Estimation ◽  
Effective Parameters ◽  
One Dimensional ◽  
The One

Introduction: Studying dam break and the resultant flood routing along with identifying critical areas at the dam downstream are of great importance in safety management of the dam break issues. To reduce the risk of the dam break, an accurate estimation of the effective parameters on the energy dissipation due to the collapse of dams and the flood routing around the downstream natural and artificial obstacles is necessary. Methods: In this research, effects of downstream obstacles (e.g. bridge piers) caused by dam break were investigated on different flood patterns in the flow characteristics. Accordingly, two different geometries of the long and wide reservoirs were considered in the experimental tests and 3D numerical simulations. Results and Conclusion: The results indicated the formation of different flow patterns at downstream of the long and wide reservoirs depends on the reservoir geometry. Due to the alignment of the channel and the reservoir in the long reservoir case, the dominant flow was one-dimensional up to the collision with the pier. Therefore, the one-dimensional solutions, including Ritter analytical solution could be applied in this range. After the flow passes through the pier, due to the formation of the wake vortices, the one-dimensional state was no longer valid. This caused turbulence at the surface of the water, which continued to the end of the channel. In the wide reservoir, from the beginning of the flow entry into the channel until its moment of collision with the pier, as well as passing through it, the flow lost its one-dimensional state. In such a case, the use of 3D models was necessary to achieve the appropriate accuracy.

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