Numerische Simulation von Hochwässern: Von 1D zu 3D aus Anwendersicht im Ingenieurbereich

Faber, R.; Fuchs, Martin; Puchner, Georg

doi:10.1007/s00506-012-0404-0

Cited by 7 publications

(4 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The increasing availability of detailed observation data, advancing methods in flow observation and terrestrial surveys, increasing computational power by the use of GPU (graphics processing unit)-based simulations and better parallelization techniques have led to an ongoing optimisation of FIM (compare García-Feal et al, 2018;Loretz & Volz, 2017;Cea & Bladé, 2015;Faber, Fuchs, & Puchner, 2012;Neal, Fewtrell, Bates, & Wright, 2010;Rauchlatner & Höppl, 2009;Mandlburger et al, 2009). The coupling procedure has been further developed to more integrated concepts by the use of distributed hydrological models and integrated hydrological and hydrodynamic modules in one model system only (compare Bates & De Roo, 2000;Howes, Abrahams, & Pitman, 2006;Cea, Puertas, Pena, & Garrido, 2008;Cea & Bladé, 2015).…”

Section: Motivation and Research Gapmentioning

confidence: 99%

Flood hazard analysis in small catchments: Comparison of hydrological and hydrodynamic approaches by the use of direct rainfall

David

Schmalz

2020

J Flood Risk Management

View full text Add to dashboard Cite

The classical 'decoupled' approach for fluvial flooding makes use of hydrographs as input boundary conditions. The catchment hydrology is determined by empirical semi-distributed rainfall-runoff models, the flood processes by the use of hydrodynamic models. However, for urban floods, the distributed rainfall is set directly as input ('direct rainfall modelling'-DRM) to the elements of the 2D model. This 'integrated approach' aims to include hydrological and hydraulic processes in one single model. In this study, both modelling approaches are applied and evaluated for their suitability to determine flood hazards in small, rural catchments. The resulting flood maps and flow hydrographs are compared for selected rainfall-runoff events in a catchment located in Central Germany. In the first approach, the hydrological model (HEC-HMS) from the Hydrologic Engineering Center (HEC) is used to generate the inflow boundary hydrographs for the 2D model (HEC-RAS), which is then used to simulate the flow variables for the river network and its floodplains. For the second approach, the DRM is applied over the whole catchment by the use of HEC-RAS. Special focus is given for the integrated approach to the difficulties occurring during the model optimisation and calibration. The comparison of the results and modelling processes of both approaches give insights into the advantages, disadvantages and difficulties or limitations of each presented approach. K E Y W O R D S direct rainfall modelling (DRM), flash flood, flood inundation modelling (FIM), HEC-RAS, hydraulic modelling, hydrological modelling, pluvial flooding, small catchments

show abstract

Section: Motivation and Research Gapmentioning

confidence: 99%

Flood hazard analysis in small catchments: Comparison of hydrological and hydrodynamic approaches by the use of direct rainfall

David

Schmalz

2020

J Flood Risk Management

View full text Add to dashboard Cite

show abstract

“…Lange et al 2015) as well as in flood risk management applications. Especially in southern Germany and Austria, HYDRO_AS-2D became a standard 2D modelling system for hydrodynamic model applications (Faber et al, 2012). Due to the numerical approaches used in the modelling system, HYDRO_AS-2D is capable of accurately simulating mass exchange between channel and forelands, streams comprising hydraulic jumps, steep channel sections as well as high variability of channel width (Nujić, 2006).…”

Section: The Hydrodynamic Model Hydro_as-2dmentioning

confidence: 99%

Hydrodynamic simulation of the effects of in-channel large woody debris on the flood hydrographs of a low mountain range creek, Ore Mountains, Germany

Rasche¹,

Reinhardt‐Imjela²,

Schulte³

et al. 2019

Preprint

View full text Add to dashboard Cite

Abstract. Fifteen years after introducing the European Union's water framework directive (WFD), most of the German surface water bodies are still far away from having the targeted good ecological status or potential. One reason are insufficient hydromorphological diversities such as riverbed structure including the absence of natural woody debris in the channels. The presence of large woody debris (LWD) in river channels can improve the hydromorphological and hydraulic characteristics of rivers and streams and therefore act positively on a river’s ecology. On the contrary, floating LWD is a potential threat for anthropogenic goods and infrastructure during flood events. Concerning the contradiction of potential risks as well as positive ecological impacts, addressing the physical effects of large woody debris is highly important, for example to identify river sections in which large woody debris can remain or can be reintroduced. Hydrodynamic models offer the possibility of investigating the hydraulic effects of fastened large woody debris. In such models roughness coefficients are commonly used to implement LWD, however, because of the complexity of the shape of LWD elements this approach seems to be too simple and not appropriate to simulate its diverse effects especially on flood hydrographs. Against this background a two-dimensional hydraulic model is set up for a mountain creek to simulate the hydraulic effects of LWD and to test different methods of LWD implementation. The study area comprises a 282 m long reach of the Ullersdorfer Teichbächel, a creek in the Ore Mountains (South-eastern Germany). In previous studies, field experiments with artificially generated flood events have been performed with and without LWD in the channel. Discharge time series from the experiments allow a validation of the model outputs with field observations. Methodically, in-channel roughness coefficients are changed iteratively for retrieving the best fit between mean simulated and observed flood hydrographs with and without LWD at the downstream reach outlet. In addition, roughness values are modified at LWD positions only and, simplified discrete elements representing LWD were incorporated into the calculation mesh. In general, the model results reveal a good simulation of the observed flood hydrographs of the field experiments without in-channel large woody debris. This indicates the applicability of the model used in the studied reach of a creek in low mountain ranges. The best fit of simulation and mean observed hydrograph with in-channel LWD can be obtained when increasing in-channel roughness through decreasing Strickler coefficients by 30 % in the entire reach or 55 % at LWD positions only. However, the increase of roughness in the entire reach shows a better simulation of the observed hydrograph, indicating that LWD elements affect sections beyond their own dimensions i.e. by forming downstream wake fields. The best fit in terms of the hydrograph's general shape can be achieved by integrating discrete elements into the calculation mesh. The emerging temporal shift between simulation and observation can be attributed to mesh impermeability and element dimensions causing too intense water retention and flow alteration. The results illustrate that the mean observed hydrograph can be satisfactorily modelled using roughness coefficients. Nevertheless, discrete elements result in a better fitting shape of the simulated hydrograph. In conclusion, a time-consuming and work-intensive mesh manipulation is suitable for analysing detailed flow conditions using computational fluid dynamics (CFD) on small spatio-temporal scale. Here, a close-to-nature design of discrete LWD objects is essential to retrieve accurate results. In contrast, the reach-wise adjustment of in-channel roughness coefficients is useful in larger scale model applications such as 1D-hydrodynamic or rainfall-runoff simulations on catchment scale.

show abstract

“…Die 3DNumerik ist (noch) eher an den Universitäten angesiedelt, doch der Bedarf an solchen Untersuchungen nimmt in der Praxis deutlich zu [6]. Die Möglichkeit, im frühen Planungsstadium mit verhältnis mäßig geringem Mehraufwand das ge wählte Design zumindest grob überprüfen zu können, ist dabei besonders von Vorteil.…”

Section: Motivationunclassified

Anregungen zur Qualitätssicherung in der 3-D-numerischen Modellierung mit FLOW-3D

Gabl¹,

Gems²,

Aufleger³

et al. 2014

Wasserwirtsch

View full text Add to dashboard Cite

Numerische Simulation von Hochwässern: Von 1D zu 3D aus Anwendersicht im Ingenieurbereich

Cited by 7 publications

References 2 publications

Flood hazard analysis in small catchments: Comparison of hydrological and hydrodynamic approaches by the use of direct rainfall

Flood hazard analysis in small catchments: Comparison of hydrological and hydrodynamic approaches by the use of direct rainfall

Hydrodynamic simulation of the effects of in-channel large woody debris on the flood hydrographs of a low mountain range creek, Ore Mountains, Germany

Anregungen zur Qualitätssicherung in der 3-D-numerischen Modellierung mit FLOW-3D

Contact Info

Product

Resources

About