The influence of grid shape and grid size on hydraulic river modelling performance

Bomers, Anouk; Schielen, Ralph Mathias Johannes; Hulscher, Suzanne J.M.H.

doi:10.1007/s10652-019-09670-4

Cited by 62 publications

(57 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The 2-D cells are a combination of curvilinear (in the main channels) and triangular grid cells. The grid creation was introduced and recommended by Bomers et al (2019) and Kernkamp et al (2011). The grid/element sizes vary from about 0.1 km in rivers to 3 km on the delta shelf.…”

Section: Grid Generation and Improvementmentioning

confidence: 99%

Flooding in the Mekong Delta: the impact of dyke systems on downstream hydrodynamics

Thanh

Roelvink

Wegen

et al. 2020

Hydrol. Earth Syst. Sci.

View full text Add to dashboard Cite

Abstract. Building high dykes is a common measure of coping with floods and plays an important role in agricultural management in the Vietnamese Mekong Delta. However, the construction of high dykes causes considerable changes in hydrodynamics of the Mekong River. This paper aims to assess the impact of the high-dyke system on water level fluctuations and tidal propagation in the Mekong River branches. We developed a coupled 1-D to 2-D unstructured grid using Delft3D Flexible Mesh software. The model domain covered the Mekong Delta extending to the East (South China Sea) and West (Gulf of Thailand) seas, while the scenarios included the presence of high dykes in the Long Xuyen Quadrangle (LXQ), the Plain of Reeds (PoR) and the Trans-Bassac regions. The model was calibrated for the year 2000 high-flow season. Results show that the inclusion of high dykes changes the percentages of seaward outflow through the different Mekong branches and slightly redistributes flow over the low-flow and high-flow seasons. The LXQ and PoR high dykes result in an increase in the daily mean water levels and a decrease in the tidal amplitudes in their adjacent river branches. Moreover, the different high-dyke systems not only have an influence on the hydrodynamics in their own branch, but also influence other branches due to the Vam Nao connecting channel. These conclusions also hold for the extreme flood scenarios of 1981 and 1991 that had larger peak flows but smaller flood volumes. Peak flood water levels in the Mekong Delta in 1981 and 1991 are comparable to the 2000 flood as peak floods decrease and elongate due to upstream flooding in Cambodia. Future studies will focus on sediment pathways and distribution as well as climate change impact assessment.

show abstract

Section: Grid Generation and Improvementmentioning

confidence: 99%

Flooding in the Mekong Delta: the impact of dyke systems on downstream hydrodynamics

Thanh

Roelvink

Wegen

et al. 2020

Hydrol. Earth Syst. Sci.

View full text Add to dashboard Cite

show abstract

“…The model is calibrated such that measured water levels are accurately predicted. Hydraulic model calibration is most commonly done by changing the roughness of the main channel until simulated water levels are close to measured water levels (Bomers et al 2019b). In this study, the same approach was used with the criterion that the calibration must lead to a maximum difference between measured and simulated water levels of 10 cm.…”

Section: Model Environmentmentioning

confidence: 99%

Consequences of dike breaches and dike overflow in a bifurcating river system

2019

Self Cite

View full text Add to dashboard Cite

Currently, the effect of dike breaches on downstream discharge partitioning and flood risk is not addressed in flood safety assessments. In a bifurcating river system, a dike breach may cause overland flows which can change downstream flood risk and discharge partitioning. This study examines how dike breaches and overflow affect overland flow patterns and discharges of the rivers of the Rhine delta. For extreme discharges, an increase in flood risk along the river branch with the smallest discharge capacity was found, while flood risk along the other river branches was reduced. Therefore, dike breaches and resulting overland flow patterns must be included in flood safety assessments.

show abstract

“…This hybrid grid overcomes the shortcomings of a curvilinear grid. It also reduces the computational time while model accuracy stays sufficient (Bomers et al, 2019). (Deltares, 2016).…”

Section: High-fidelity Modelmentioning

confidence: 99%

“…During calibration, this numerical grid generated friction will be compensated such that reliable water levels are predicted. Hydraulic model calibration is most commonly done by changing the roughness of the summer bed until simulated water levels are close to measured water levels (e.g Bomers et al (2019) and Caviedes-Voullième et al (2012)). In this study, the 265 same approach was used.…”

Section: High-fidelity Modelmentioning

confidence: 99%

Application of a lower-fidelity surrogate hydraulic model for historic flood reconstruction

Bomers

Schielen

Hulscher

2019

Environmental Modelling & Software

Self Cite

View full text Add to dashboard Cite

Two dimensional hydraulic models are useful to reconstruct maximum discharges and uncertainties of historic flood events. Since many model runs are needed to include the effects of uncertain input parameters, a sophisticated 2D model is not applicable due to computational time. Therefore, this papers studies whether a lower-fidelity model can be used instead. The presented methodological framework shows that a 1D-2D coupled model is capable of simulating maximum discharges with high accuracy in only a fraction of the calculation time needed for the high-fidelity model. Therefore, the lower-fidelity model is used to perform the sensitivity analysis. Multiple Linear Regression analysis and the computation of the Sobol' indices are used to apportion the model output variance to the most influential input parameters. We used the 1926 flood of the Rhine river as a case study and found that the roughness of grassland areas was by far the most influential parameter.

show abstract

The influence of grid shape and grid size on hydraulic river modelling performance

Cited by 62 publications

References 21 publications

Flooding in the Mekong Delta: the impact of dyke systems on downstream hydrodynamics

Flooding in the Mekong Delta: the impact of dyke systems on downstream hydrodynamics

Consequences of dike breaches and dike overflow in a bifurcating river system

Application of a lower-fidelity surrogate hydraulic model for historic flood reconstruction

Contact Info

Product

Resources

About