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Coastal defenses must be upgraded to combat increasing flood risk due to climate change and other factors. Storm surge barriers, large movable hydraulic structures that close temporarily during storm surges to prevent coastal floods, play a vital role in protecting estuaries. Due to the complexity of their risk analyses, important improvements are sometimes overseen. Our objective is to develop a systematic approach which is more likely to find these important improvements. We tested the method to three historic cases where important improvements were initially overlooked. We anticipate that our method can be applied to other safety systems with a large number of failure modes as well., Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Hydraulic Structures and Flood Risk

The efficacy of risk models and risk analyses critically hinges on sufficient model evaluation. Nevertheless, the usefulness for the intended purpose is rarely systematically assessed. Poor or even lacking model evaluation of the applied risk models and analyses also troubles the asset management of storm surge barriers in the Netherlands. In practice, obvious flaws, missing failure modes and use that deviates from the original purpose regularly lead to unpleasant surprises, unnecessary costs and avoidable risks. Here, we introduce new guidelines for the quality control during the development, testing, maintenance and usage of risk analyses of critical hydraulic structures. First responses among stakeholders are rather positive since the guidelines help modelers and analysts to better understand critics and independent reviewers to structure their comments. However, the efficacy of the guidelines itself also need rigorous evaluation in the coming years. This may prove challenging as the application of the guidelines may also reveal that the organizations that operation the storm surge barriers are currently insufficiently equipped for the rigorous quality control of risk models and risk analyses., Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Hydraulic Structures and Flood Risk

In the coming decades, the storm surge barriers in the Netherlands will reach their end of the designed life time of 100 years. Therefore, the Dutch storm surge barriers are preparing for major renovations. Next to this, as a result of the expected sea level rise, the hydraulic loads and the number of necessary closures will exceed the original design requirements. This gives urgency to look further than an one-to-one replacement or conservation and it a good moment to include changes in functional requirements. The functional end of life is, however, typically surrounded by large uncertainties. Since storm surge barriers bear multiple functions (e.g. hydraulic safety, the environment, shipping and road traffic infrastructure connection), changes in conditions can lead in several ways to the functional end of life. In this paper we explore what aspects should be added to current asset management strategy to include the functional performance of our hydraulic structures., Hydraulic Structures and Flood Risk

Next decades, many hydraulic structures in the Netherlands will reach their end of life. Timely mitigation requires accurate estimates of the end of life. This appears however hard since many external drivers and multiple functions may lead in many plausible combinations to insufficient technical or functional performance. As a consequence, a complete integrated assessment is rather labour intensive and time consuming. This study shows a quick-scan of the end of life of five storm surge barriers and three other critical hydraulic structures in the Netherlands. The quick-scan reveals that sea-level rise is the major driver for the end of life of most coastal hydraulic structures since it impacts both the free discharge capacity and the flood protection function. Yet, the strategy to adapt the river delta to climate change may be even more important. Future developments are however such uncertain that the life time assessments may prove especially useful for the exploration of adaptive asset management strategies and to a lesser extent as an accurate planning tool., Hydraulic Structures and Flood Risk

The pumping-weir complex at IJmuiden plays an important role in the drainage of excess water in the Western Netherlands. Multiple pumps need replacing as 4 out of 6 pumps near their end-of-life term. The optimal replacement strategy critically hinges on the future required pumping capacity. Yet, currently available models are not suited to assess the effect of sea level rise or extremer precipitation events as they ignore certain complexities of the water system. Preliminary data analysis in this paper showed the sensitivities of the system. The required pumping capacity is sensitive to the ability of free discharging during extreme water events. Yet, it is less susceptible to extremer precipitation events. Further research will aim at including more of the water system’s complexity in the model. Due to the node-like structure and high availability of data, a neural network modelling approach will probably be suitable., Hydraulic Structures and Flood Risk

Storm surge barriers are large movable hydraulic structures which close during a storm surge to prevent coastal floods. In the regions they protect, a failure to close the barrier is often the most likely cause for a catastrophic flood. Nevertheless, flood risk assessments usually only focus on raising flood defences behind the barrier. Despite its importance, there is no general method to assess the costs and benefits of improving the closure reliability. This paper presents a model that optimises investments considering both closure reliability improvements and raising flood defences behind the barrier, using the region protected by the Maeslant barrier as a case. We substantiate that constructing the Maeslant barrier was an optimal economic decision. Moreover, we demonstrate large investments such as a redundant barrier already being economically sound with a few decimetres of sea level rise. Based on our experience with this case study, we expect the model is useful in finding strategies to adapt to rising sea levels and other developments that cause coastal flood risk to rise worldwide., Hydraulic Structures and Flood Risk

Over the course of the last century, storm surge barriers have been built in several countries and proven to be successful in preventing flooding. However, the operation, reliability, and remaining life of these structures have come under increased pressure due to changing demands, intensified utilisation, and climate change. Yet, there is relatively little known about how these factors affect the remaining life of storm surge barriers. To address this issue, a framework is presented to assess the impacts of external drivers on the remaining life in a systematic manner. The framework considers both the technical state and functional performance and uses scenarios to evaluate the impact of external drivers. The application of the framework is demonstrated for the Hollandsche IJssel barrier (the Netherlands). The results indicate that sea level rise (SLR) is the dominant physical driver. Even in moderate SLR scenarios, the lifespan of the barrier may end in the 2040s if the functional performance with respect to flood protection and navigation cannot be improved. Ultimately, the study demonstrates how the remaining life of storm surge barriers could be assessed systematically and the impact of external drivers on the remaining life could be evaluated., Hydraulic Structures and Flood Risk, Integral Design & Management

Simple models can play pivotal roles in the quantificationand framing of uncertainties surrounding climatechange and sea-level rise. They are computationally efficient,transparent, and easy to reproduce. These qualities also makesimple models useful for the characterization of risk. Simplemodel codes are increasingly distributed as open source,as well as actively shared and guided. Alas, computer codesused in the geosciences can often be hard to access, run,modify (e.g., with regards to assumptions and model components),and review. Here, we describe the simple modelframework BRICK (Building blocks for Relevant Ice andClimate Knowledge) v0.2 and its underlying design principles.The paper adds detail to an earlier published modelsetup and discusses the inclusion of a land water storagecomponent. The framework largely builds on existing modelsand allows for projections of global mean temperatureas well as regional sea levels and coastal flood risk. BRICKis written in R and Fortran. BRICK gives special attention tothe model values of transparency, accessibility, and flexibilityin order to mitigate the above-mentioned issues while maintaininga high degree of computational efficiency.We demonstratethe flexibility of this framework through simple modelintercomparison experiments. Furthermore, we demonstratethat BRICK is suitable for risk assessment applications byusing a didactic example in local flood risk management.

In dit artikel zijn meerder methoden beschreven om een schatting te maken van de kans op extreme hoge afvoeren rond het jaar 2050 in het stroomgebied van de Rijn. Hierbij geven we inzicht in de verschillen in de schattingen die ontstaan door op verschillende manieren de klimaatscenario’s te gebruiken.

Het KNMI heeft een computertransformatieprogramma ontwikkeld als aanvulling op de KNMI'06-klimaatscenario's. Hiermee kan een historische neerslag- of temperatuurreeks op dagbasis omgezet worden in een reeks die past bij het klimaat onder één van de vier KNMI'06-klimaatscenario's voor een bepaalde tijdshorizon. In dit artikel wordt toegelicht hoe het programma werkt voor neerslag en wat de mogelijkheden en beperkingen zijn