Statistical Assessment of Storm Surge Scenarios Within Integrated Risk Analyses

Burzel

et al. 2015

Self Cite

Coast. Eng. J. 2015.57. Downloaded from www.worldscientific.com by UNIVERSITY OF CALIFORNIA @ SAN DIEGO on 06/03/15. For personal use only. H. Oumeraci et al.A brief overview of the joint research project XtremRisK is given. The project has been focusing on developing/improving/expanding the knowledge, methods and models with respect to (i) physically possible extreme storm surge for current conditions and scenarios for climate change, (ii) failure mechanisms of flood defenses, (iii) assessment of intangible losses (social and ecological) and their integration with direct/indirect economic losses, (iv) reliability analysis of flood defense systems and (v) sourcepathway-receptor (SPR)-based integrated flood risk analysis involving both tangible and intangible losses and its implementation for two selected pilot sites (representative for an open coast and an urban estuarine area in Germany). The key results are briefly summarized and the lessons learned for future flood risk studies are finally drawn.

Section: Key Resultsmentioning

confidence: 99%

Section: Key Resultsmentioning

confidence: 99%

Section: Lessons Learnedmentioning

confidence: 99%

See 1 more Smart Citation

XtremRisK — Integrated Flood Risk Analysis for Extreme Storm Surges at Open Coasts and in Estuaries: Methodology, Key Results and Lessons Learned

Burzel

et al. 2015

Self Cite

“…This nonlinearity was confirmed and further detailed by Tayel and Oumeraci [2015] using a hybrid approach based on a hydrodynamic model and an artificial neural network. Wahl et al [2015] used a statistical approach to propose a storm surge generator, including not only the maximum water level during a storm surge but also its time history. Joint probabilities were estimated for different storm surge scenarios taking into account the water level but also its duration and wave parameters.…”

Section: About This Issuementioning

confidence: 99%

XtremRisK — Today's and Future Coastal Flood Risks Under Extreme Events

2015

About Flood RiskClimate change and sea level rise, storm surges and hurricanes, sustainability and preparedness are keywords when dealing with safety issues and flood protection along the world's coasts and estuaries. Scientific investigations and political discussions of the related questions are manifold and have looked into various aspects of coastal flood risk. However, the definition of "risk" alone has kept scientists busy all over the world and whilst disputes about its meaning can be found in literature, an easy-to-apply generic definition is yet simply not available.The term "risk" has been developed involving a wide range of disciplines all of which seem to have different viewpoints and definitions of risk. It is therefore inevitable to define its meaning before commencing any risk assessment or risk management attempts. The papers in this issue deal with various aspects of coastal flood risk in general and most of them use an engineering approach to risk which is defined here as the probability of a flood times its consequences. Whilst this seems a straightforward definition it implies numerous questions which have not been answered and some of which have not even been addressed yet. What con-1502001-1

“…Eng. J., this special issue; Wahl, T. et al [2015] "Statistical assessment of storm surge scenarios within integrated risk analyses," Coast. Eng.…”

mentioning

confidence: 99%

Reliability-Based Flood Defense Analysis in an Integrated Risk Assessment

Naulin

2015

Failures of flood defenses have been one of the major reasons in the past leading to flooding of the hinterland behind flood defenses along rivers and at the sea. It is therefore inevitable to investigate the reliability of such defenses for extreme events as have occurred in the past and are discussed to happen more frequently in the future and due to climate changes. The first subproject in XtremRisK (SP 1) and the related papers in this issue "A multi-method approach to develop extreme storm surge events to strengthen the resilience of highly vulnerable coastal areas," Coast. Eng. J., this special issue; Wahl, T. et al. [2015] "Statistical assessment of storm surge scenarios within integrated risk analyses," Coast. Eng. J., this special issue; Tayel, M. and Oumeraci, H.[2015] "A hybrid approach using hydrodynamic modelling and artificial neural networks for extreme storm surge prediction, Coast. Eng. J., this special issue] have investigated the components of storm surges and their statistical occurrence, also in relation to the wave parameters. These results can now be used as input for investigating the reliability of flood defenses and provide an overall failure probability for different types of defenses and different failure modes. This paper therefore summarizes the key findings of the "risk pathway" analysis of XtremRisK Subproject 2 (SP 2) which comprise a reliability analysis 1540005-1 M. Naulin, A. Kortenhaus & H. Oumeraciand breach modeling of coastal and estuarine flood defenses using storm surge scenarios and sea states, including their occurrence probabilities provided by XtremRisK SP 1. The paper discusses the key results, the progress, and challenges in reliability analysis and breach modeling of flood defenses. The developed and advanced methods were applied to pilot sites in Hamburg (Elbe Estuary) and the Island of Sylt (North Sea). These pilot sites are mainly protected by linear flood defenses such as sea dikes, estuarine dikes, coastal dunes, and flood defense walls. Results have shown that under extreme conditions many dikes may fail simply from wave overtopping and even overflow but also from dike breaching due to the severe loading of the dike slopes when heavy overtopping and overflow occurs. The inflowing water volumes were calculated based on time-dependent water levels and then used for inundation modeling of the hinterland in Subproject 3 (SP 3) of XtremRisK. Furthermore, the limit state equations for wave overtopping and overflow had been adapted to time-dependent simulations. An importance factor was introduced for the probability of breaching of sea dikes leading to significantly different failure probabilities. The length effect considering the different homogeneous segments in the dike ring of Hamburg-Wilhelmsburg was estimated using an upper and lower bound approach showing the importance of the segmentation of the dike ring.