Analysis of flood hazard under consideration of dike breaches [Elektronische Ressource] / von Sergiy Vorogushyn

Sergiy Vorogushyn

Informations

• Publié par: universitat_potsdam
• Publié le: 01 janvier 2008
• Nombre de lectures: 37
• Langue: English
• Poids de l'ouvrage: 53 Mo

Extrait

Analysis of flood hazard under consideration
of dike breaches
Dissertation
zur Erlangung des akademischen Grades
"doctor rerum naturalium" (Dr. rer. nat.)
in der Wissenschaftsdisziplin "Geoökologie"
eingereicht an der
Mathematisch-Naturwissenschaftlichen Fakultät
der Universität Potsdam
von
Sergiy Vorogushyn
Potsdam, 2008This work is licensed under a Creative Commons License:
Attribution - Noncommercial - No Derivative Works 3.0 Germany
To view a copy of this license visit
http://creativecommons.org/licenses/by-nc-nd/3.0/de/deed.en







































Online published at the
Institutional Repository of the Potsdam University:
http://opus.kobv.de/ubp/volltexte/2009/2764/
urn:nbn:de:kobv:517-opus-27646
[http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-27646] Contents
Abstract 6
Zusammenfassung 8
1 Introduction 11
1.1 Identification of the research niche and thesis aims . . . . . . . . . . . . . . . . . . . . 11
1.2 Structure of the thesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2 Flood inundation modelling and hazard assessment 15
2.1 One-dimensional models for inundation prediction . . . . . . . . . . . . . . . . . . . . 15
2.1.1 Planar surface interpolation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.1.2 1D hydrodynamic modelling approach . . . . . . . . . . . . . . . . . . . . . . . 15
2.2 Two-dimensional models for inundation prediction . . . . . . . . . . . . . . . . . . . . 16
2.2.1 Storage cell inundation models . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.3 Hybrid models for prediction . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.4 Constraining inundation model uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.4.1 In-situ measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.4.2 Inundation extent observations . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.4.3 Water levels extracted from inundation extent observations . . . . . . . . . . . . 21
2.4.4 Satelite radar altimetry and interferometric synthetic aperture radar . . . . . . . 22
2.5 Flood hazard assessment under defence failure . . . . . . . . . . . . . . . . . . . . . . . 23
2.6 Framing of modelling approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3 Inundation hazard assessment model (IHAM) 26
3.1 Model structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.1.1 1D hydrodynamic module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.1.2 Dike breach module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.1.3 2D h module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3.1.4 Coupling of core modelling components . . . . . . . . . . . . . . . . . . . . . . 29
3.1.5 Input data and pre-processing . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
3.1.6 Post-processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
3.2 Overview of dike breach mechanisms . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.2.1 Dike breach statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
3.2.2 Fault tree . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
3.3 Probabilistic dike failure assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
3.3.1 Dike failure due to overtopping . . . . . . . . . . . . . . . . . . . . . . . . . . 38
3.3.2 Dike failure due to rupture and piping . . . . . . . . . . . . . . . . . . . . . . . 39
3.3.3 Dike failure due to seepage and micro-instability . . . . . . . . . . . . . . . . . 46
33.3.4 Breach development and width . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
4 Application of IHAM to the Middle Elbe reach 51
4.1 Modelling objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
4.2 Description of the study reach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
4.3 1D hydrodynamic model setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
4.3.1 Calibration and validation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
4.4 Dike breach model setup and sensitivity analysis . . . . . . . . . . . . . . . . . . . . . 63
4.4.1 Dike input data and pre-processing . . . . . . . . . . . . . . . . . . . . . . . . . 63
4.4.2 Fragility curves for overtopping . . . . . . . . . . . . . . . . . . . . . . . . . . 64
4.4.3 curves for piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
4.4.4 Fragility curves for micro-instability . . . . . . . . . . . . . . . . . . . . . . . . 71
4.4.5 Stochastic breach width modelling . . . . . . . . . . . . . . . . . . . . . . . . . 73
4.5 Storage cell inundation model setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
4.5.1 Model parameterisation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
4.5.2 evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
4.6 Generation of synthetic flood scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
4.6.1 Synthetic input hydrographs for the main river . . . . . . . . . . . . . . . . . . 79
4.6.2 Tributary input h . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
4.7 Flood hazard analysis for the reach Torgau-Vockerode . . . . . . . . . . . . . . . . . . . 82
4.7.1 Dike breach hazard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
4.7.2 Inundation hazard and associated uncertainty . . . . . . . . . . . . . . . . . . . 88
4.7.3 Uncertainty of discharge hydrographs . . . . . . . . . . . . . . . . . . . . . . . 101
4.8 Assessment of polder retention effect on flood hazard . . . . . . . . . . . . . . . . . . . 104
4.8.1 Model setup and objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
4.8.2 Impact on river discharge hydrographs . . . . . . . . . . . . . . . . . . . . . . . 106
4.8.3 on dike breach probability . . . . . . . . . . . . . . . . . . . . . . . . . 107
4.8.4 Impact on flood hazard indicators . . . . . . . . . . . . . . . . . . . . . . . . . 108
5 Conclusions and perspectives 112
5.1 Summary of novel implementations and key findings . . . . . . . . . . . . . . . . . . . 112
5.2 Recommendations for model improvement and future perspectives . . . . . . . . . . . . 116
5.2.1 Limitations of the IHAM approach . . . . . . . . . . . . . . . . . . . . . . . . . 116
5.2.2 Towards enhanced representation of fluvial inundation processes . . . . . . . . . 117
5.2.3 Towards a hazard assessment on regional scale . . . . . . . . . . . . . . . . . . 118
Bibliography 119
Appendices 131
A 132
A.1 Derivation of a slide height for micro-instability . . . . . . . . . . . . . . . . . . . . . . 132
A.2 Derivation of slide bend heighth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1332
B 137
C 141
List of Symbols 153
4List of Figures 161
List of Tables 163
5Abstract
River reaches protected by dikes exhibit high damage potential due to strong value accumulation in the
hinterland areas. While providing an efficient protection against low magnitude flood events, dikes may
fail under the load of extreme water levels and long flood durations. Losses arising from subsequent
inundation may be dramatic not only because of the high value concentration in the hinterland, but
additionally due to fast water level rise and high flow velocities caused by rapid breach outflow.
Hazard and risk assessments for river reaches protected by dikes have not adequately considered the
fluvial inundation processes up to now. Particularly, the processes of dike failures and their influence on
the hinterland inundation and flood wave propagation lack comprehensive consideration. Uncertainties
in inundation characteristics related to the dike breach processes were not yet reported. To fill this gap
and enable a more adequate flood hazard assessment for diked reaches, a new modelling approach is
required.
This study focuses on the development and application of a new modelling system which allows
a comprehensive flood hazard assessment along diked river reaches under consideration of dike fail-
ures. The proposed Inundation Hazard Assessment Model (IHAM) represents a hybrid probabilistic-
¯ ¯ ¯ ¯
deterministic model. It comprises three models interactively coupled at runtime. These are: (1) 1D
unsteady hydrodynamic model of river channel and floodplain flow between dikes, (2) probabilistic dike
breach model which determines possible dike breach locations, breach widths and breach outflow dis-
charges, and (3) 2D raster-based diffusion wave storage cell model of the hinterland areas behind the
dikes. Due to the unsteady nature of the 1D and 2D coupled models, the dependence between hydraulic
load at various locations along the reach is explicitly considered.
The probabilistic dike breach model describes dike failures due to three failure mechanisms: over-
topping, piping and slope instability caused by the seepage flow through the dike core (micro-instability).
These