The great eastern Japan earthquake and Tsunami: Field observations on the coast of Tohoku six month later

The tsunami that hit the north pacific coast of Japan on March 11, 2011 has been characterized as a mega disaster. It inundated over 560 square kilometers of land, devastating a large number of coastal communities, causing over 20,000 casualties and huge economic damage in Tohoku region. The purpose of this report is to give insight into the magnitude of the disaster and the response of the Japanese tsunami countermeasures to it, based on which a number of questions can be formulated regarding in which direction research should go. In the beginning some background information is given regarding the affected coastline, which is useful in order for the local disaster patterns to be understood. The core content is a description of the visited areas, the local tsunami behaviour, and the damage that took place. The report ends up with some suggestions for future research.Hydraulic EngineeringCivil Engineering and Geoscience

Probabilistic design of breakwaters in shallow, hurricane-prone areas

One of the failure mechanisms of a rubble mound breakwater is the failure of its armour layer. In order to determine the stability of an armour layer, the design load has to be defined, which is in fact the wave that attacks the structure. Being a highly stochastic phenomenon, the wave action is not easily defined, while there is always some uncertainty inherent to its definition. In a deterministic calculation this uncertainty is totally overlooked, as the possible variations of the design wave height are not taken into account. In order to incorporate uncertainties into the design process, and therefore increase its reliability, probabilistic design methods should be applied. A commonly used approach is a semi-probabilistic computation on level 1, which introduces the application of partial safety coefficients, yet the indicated methods to derive and apply them do not clarify the uncertainties incorporated, adding an undefined degree of safety in the process, or end up with incorrect results under certain conditions. Another approach is a fully probabilistic computation on level 2 or 3. This type of design tackles explicitly a great deal of uncertainties, hence its results can be considered much more accurate. However it is not commonly used, due to the fact that there are not straight forward guidelines to support it, and therefore a number of critical decisions by the designers are required. The main objective of this study is to indicate the weaknesses of the existing design methods, and to suggest a design approach that is both attractive to designers and sufficiently reliable. This is achieved through application of the existing methods in an example case, whose features facilitates a critical assessment, and enables formulation of an improved approach. The chosen case is the jetties at the entrance of Galveston port, in the Gulf of Mexico, and the features of interest are the hurricane-dominated hydraulic climate and the fact that the structure is located in shallow water, meaning that the design load is determined by depth-limited waves. The design methods that are demonstrated are a classical deterministic design, a semi-probabilistic calculation on level 1 as proposed by PIANC in 1992, and a fully probabilistic calculation on level 3 with a Monte Carlo simulation. Based on the evaluation of the three design processes and the results, the new approach can be developed, which suggests a rational framework for deriving safety factors. According to it, a set of safety factors is generated which incorporate the same uncertainties as a fully probabilistic design; hence an equally reliable result is extracted. The final product is a guideline for code makers indicating the procedure to derive the safety factors and a guideline for future designers indicating the analytic steps for a proper use of the safety factors. In addition a large number of concluding remarks are summarized, which can contribute in optimizing the performed analysis. The concluding remarks refer in particular to the determination of hydraulic boundary conditions, the application of the design methods, the probabilistic model used for Monte Carlo simulation, the proposed design approach, and the safety factors derived with this approach.Hydraulic EngineeringCivil Engineering and Geoscience

Economic optimisation of flood risk management projects

The Netherlands has developed a flood risk management policy based on an economic rationale. After the flood disaster of 1953, when a large area of the south-western part of the country was flooded and more than 1800 people lost their lives, the so-called Delta Committee was installed, whose main purpose was to coordinate actions towards a drastic reduction of flood risk. A key element of the Delta Committee’s recommendations, which formed the foundation of the current flood risk management policy in the Netherlands, was the determination of protection standards for all major levee systems in the country, determined as overtopping probabilities of flood defences, and derived by means of cost-benefit analysis. This facilitated the realization of significant investments of capital in flood protection. In the 1990s the use of cost-benefit analysis became mandatory for the evaluation of all public investments in the Netherlands. This means that the rationale adopted in the 50s is not likely to be substantially changed in the coming decades. Despite the significant steps that were taken by implementing the recommendations of the Delta Committee, there is still space for improvements in the Dutch flood risk management policy. First of all, the heterogeneity of failure properties along the dyke-rings and of consequence patterns in the protected areas could be more comprehensively considered. Secondly, within the framework of an adaptable policy, there are issues that still need to be thoroughly studied, like the effect that budget constraints may have on the economic efficiency of protection standards. Thirdly, in light of increasing concerns for the potential consequences of flooding in the Netherlands, new protection standards could be determined taking into account investments in multi-layer safety. That is investments not only in flood prevention measures, but also in measures for the mitigation of losses due to flooding. Fourthly, explicit restrictions for the acceptable risk of loss of life could be provided on the basis of social and not only economic criteria, which is currently the case. Acknowledging the need for improvements, the Dutch Government has already ordered an update of the national flood risk management policy. The main objective of this dissertation is to investigate how the four aforementioned points could be addressed and accommodated in the Dutch flood risk management policy, while respecting the preservation of cost-benefit analysis as a vehicle for supporting decisions upon investments in flood protection. In particular, methods are developed for the identification of decisions that are economically optimal, hence in line with a cost-benefit rationale, when the conditions entailed in the aforementioned points are present. A second objective is to investigate the conditions under which investments in multi-layer safety are more economically appealing than investments in flood prevention only. These objectives are met in chapters 2-9. The content of each chapter is described below. Chapter 2 provides background information on the methods that are used worldwide for the formulation of public safety regulations, the pros and cons of cost-benefit analysis, and the features of economic decision problems in flood risk management. In the end an inventory of economic decision problems that are relevant in flood risk management is presented. In that inventory the problems that are compatible with the economic rationale of cost-benefit analysis are indicated. Based on this analysis the economic decision problems that are further investigated in this dissertation are clarified. Such a clarification increases understanding of the overall function of the methods presented in latter chapters, while it is important for avoiding methodological inconsistencies in the use of cost-benefit analysis. Chapter 3 focuses on the economic optimization of flood prevention systems. Using analytical approaches, economically optimal design specifications are derived for this type of systems. The analysis starts with a very simple system, i.e. a homogeneous dyke-section with one failure mechanism. Then more complex features are gradually added, i.e. multiple failure mechanisms, multiple homogeneous dyke-segments, and consequences that vary depending on the dyke-segment that fails. This is done by following a systems approach, where failure mechanisms and homogeneous dyke-segments are treated as components of a series system. In every stage of the analysis optimization formulae are derived, which show that the optimal designs are always proportional to the marginal costs of flood-control measures and inversely proportional to the protected economic values. In the cases of multiple failure mechanisms and multiple homogeneous sections the derived formulae constitute upper and lower bounds of the optimal failure probabilities, which show that the stronger the dependence among different failures, the lower the economically optimal failure probabilities. Regarding the optimal flooding probability in the system, the results indicate that the dependence of failures may not influence its value significantly. To that end, further research is recommended. Chapter 4 focuses on the economic optimization of multi-layer safety systems. In this chapter a line of thought similar to that of chapter 3 is followed. In particular, using analytical approaches, economically optimal design specifications are derived for multi-layer safety systems with two and three safety layers. For the sake of simplicity, only one measure is considered per safety layer. The analysis starts with an introduction of the possible schematizations of multi-layer safety. Then the analytical optimization of systems with two and three layers is presented, and formulae are derived for the optimal failure probability per safety layer. Just like in chapter 3, the derived formulae reveal that the optimal failure probabilities of safety layers are proportional to their marginal costs and inversely proportional to the economic values that they protect. Apart from this, it is clarified when it is more likely for a system with multiple safety layers to be more economically attractive than a prevention system. This proves to be the case primarily when the marginal cost of layer 1 gets much higher than that of higher safety layers, and secondarily when the economic value protected by multiple layers increases The analytical outcomes are validated through numerical tests in a variety of cases, where the possibility to invest in three safety layers is considered. Despite validation of the analytical results, the numerical tests indicate additional conditions that affect the likelihood of optimality of multi-layer safety, namely the increase of mortality rate in case of flooding and the occurrence of extreme loads that resemble typhoons and tsunamis. Chapter 5 investigates how budget constraints and high safety requirements for human life can influence the optimal design of both prevention and multi-layer safety systems. The analysis refers to the same system layout as the one known from chapter 4, while a similar line of thought is followed. That is that the optimal designs are derived first with the use of analytical approaches, and the results are then validated through numerical tests. The analysis starts with the analytical optimization under budget constraints. It continues with the optimization of the same system given a safety constraint that corresponds to a lower risk to human life than that in the economically optimal solution. Then a number of numerical tests are performed, showcasing the sensitivity of the optimization results to different budget and safety constraints. Regarding budget constraints, the analysis proves that the lower the available budget the more likely it is for multi-layer safety to be more economically attractive than prevention, while this likelihood may be increased in tsunami- and typhoon-prone areas. Regarding safety constraints, the analysis indicates that the higher the safety requirement for human life, the more likely it is for multi-layer safety to be preferred over prevention. In the end, the influence of constraints on the cost-effectiveness of investment strategies is investigated, which shows that safety layer 3 (i.e. emergency management) is more cost-effective when there are budget constraints than when there are safety constraints. Chapter 6 presents an analysis that indicates how uncertainty in the estimated costs of flood control measures can influence the result of an economic optimization. This uncertainty is introduced in the form of random variables in the total cost function. Subsequently a Monte Carlo simulation is performed, indicating how robust an investment strategy is, i.e. how likely it is for a strategy chosen as optimal when uncertainties were not considered, to be overtaken by another strategy after uncertainties are introduced. The analysis is performed for three cases of systems, where multi-layer safety with layers 1 and 3 proved to be optimal in chapter 5. The results of the analysis indicate that uncertainty is one of the parameters that can prevent the optimality of multi-layer safety. In Chapter 7 the theory of chapter 3 is used for the determination of economically optimal protection standards in the Netherlands. In particular, it is presented how to incorporate information about the Dutch dyke-rings provided by the national flood risk analysis project VNK2, in the analytical optimization approach of chapter 3. The suggested procedure shows that the consideration of simultaneous failures in different parts of a dyke-ring in the Netherlands has minor influence on the optimization results. In Chapter 8 a descriptive analysis is presented on the response of the multi-layer safety systems of Tohoku in Japan during the Great Eastern Japan Earthquake and Tsunami on March 11, 2011. This analysis shows in a practical manner why the failure probability of flood defences, i.e. layer 1 measures, needs to be lower than that of measures of higher safety layers, validating the boundary conditions used in the optimizations of chapter 4. In Chapter 9, the theory of chapter 4 is used for the determination of an economically optimal multi-layer safety design for Rikuzentakata, a town in Tohoku that was entirely destroyed in 2011. This confirms the applicability of the optimization model presented in chapter 4. In Chapter 10 conclusions are summarized.Hydraulic EngineeringCivil Engineering and Geoscience

Development and prototype application of an oil spill risk analysis in a coastal zone

This paper introduces the development of a methodology for performance of oil spill risk analysis in coastal zones through a prototype application. The main objective of the research effort is to develop the basis for a tool that can assess risks due to the occurrence of an oil spill event aiming at assisting to the risk response process. The methodology concerns the processes of probability and consequence assessment. The two processes are accomplished qualitatively with a risk prioritization based on Analytic Hierarchy Process. Being a decision-making technique, Analytic Hierarchy Process can only be used after some appropriate modifications, which transform it into a tool for prioritizing risks with respect to their probability and consequence in different oil spill scenarios. This is an approach that attempts to rationalise the risk analysis stages and to indicate the uncertainties imposed to the problem, hence creating a basis for optimization of the risk analysis results.Hydraulic EngineeringCivil Engineering and Geoscience

The Great Eastern Japan Earthquake and Tsunami: Facts and implications for flood risk management

The Great Eastern Japan Earthquake and Tsunami of March 11, 2011 can be characterized as a catastrophe. It inundated over 560 km2 of land, devastating a large number of coastal communities, causing over 19,000 casualties and huge economic damage in the Tohoku region. Due to the relatively high frequency of tsunamis, the region was considered well prepared against extreme coastal events. Yet the event of March 11 exceeded all previous expectations and overwhelmed the Japanese disaster protection system. This book constitutes a Dutch perspective to the Japanese tsunami disaster. Its main objective is to provide a comprehensive overview of the devastating events, their impact and the implications of this catastrophe for flood risk management in Japan, in the Netherlands, and ultimately worldwide. It is in fact the outcome of an effort to derive lessons for flood risk management based on the record of a natural disaster with a magnitude that has never been recorded before. First a brief chronicle of the events of March 11 2011 is presented, followed by the consequences and actions that took place in the aftermath of the disaster. Subsequently some insight into the damage and casualties is provided through the description of field observations in September 2011. Using this information the response of the Japanese flood countermeasures to the tsunami of March 2011 is analysed from a flood risk management perspective. The book continues with an overview of the recovery efforts, and it concludes with some future challenges for developments in disaster management, including the potential of Dutch-Japanese collaborations in the field of flood risk management.Hydraulic EngineeringCivil Engineering and Geoscience

A Systematic Approach of Greek Coastal Zone Management

Additional MSc thesis Greece owns the most extensive coastline of all European countries. Greek economy relies on the protection and the development of the coast, where major economic activities take place and where about 60% of the population lives. Despite the crucial role of the coastal zone in Greece, there is no organized integrated act with regard to coastal zone management. This project introduces the development and application of a database of all the Greek coasts. The main objective of this project is to take a first step towards an integrated coastal zone management, by developing a tool for primarily identifying any piece of Greek coast, and secondarily accomplishing a coastal classification with regard to physical characteristics and social-economic activities. In order to decide about the content of the database and to come up with a proper structure, it was first necessary to define the main issues related to the Greek coasts, such as touristic development or environmental protection of a wetland, as well as to identify the possible users of the database and the kind of information that they would demand. The range of possible users has proved to be very wide, and therefore the range of information included in the database is wide too. The main data fields are the following: \u95 Type of coast: beach / rocky coast / wetland / port etc \u95 Geographical aspects: coordinates / province / prefecture \u95 Physical aspects: geological features/ beach length, width/ sediment grain size \u95 Hydraulic aspects: wind speed and direction / significant wave height \u95 Other general aspects: existence of fisheries / industry / urbanized areas etc. The database has been developed with web-based software and is accessible via the internet in the address www.greekcoasts.info.Hydraulic EngineeringCivil Engineering and Geoscience

Embedding carbon impact assessment in multi-criteria supplier segmentation using ELECTRE TRI-rC

In the past decade, there has been an increasing interest in green supply chain management, which integrates environmental thinking into supply chain management. Assessing a supplier’s potential for improvement is very important when an organization wants to achieve certain environmental targets concerning their supply base, taking into account the limited resources available. In this paper, incorporating environmental evaluation criteria into a comprehensive supplier segmentation approach called ‘supplier potential matrix’ (SPM), a green supplier segmentation is proposed to segment the suppliers. Two overarching dimensions—supplier’s capabilities and supplier’s willingness—are used to evaluate the supplier’s green potential. The two dimensions are measured by multiple criteria. A sorting method called ELECTRE TRI-rC is used to solve the resulted multi-criteria decision-making problem. In order to make a more meaningful distinction, a simple method is also proposed to assess the suppliers with respect to the carbon footprint of the raw materials they supply. The results of this assessment are combined with the ones of the SPM, resulting in a more useful segmentation. The proposed model is applied to a sample containing the suppliers of a large international company.</p

Economic optimization of flood prevention systems in the Netherlands

After the flood disaster of 1953, the Netherlands adopted a rational approach to flood risk management with the use of protection standards determined by means of cost-benefit analysis. Due to scientific and political developments that have recently taken place, an update of the Dutch protection standards is being undertaken. One of the major priorities considered, is the need to address three issues, namely: (1) expressing the protection standards as failure probabilities of the flood defences, i.e. probabilities of breaching, instead of exceedance frequencies of water levels that is currently the case, (2) taking into account a spatial variability of those failure probabilities, and (3) considering various flooding scenarios. These aspects have been comprehensively addressed within a national flood risk analysis project, and partly considered in a numerical cost-benefit analysis approach, developed for the determination of new protection standards in the Netherlands. This paper presents an analytical economic optimization approach that makes an explicit link with all results of the national flood risk analysis project. In particular, an approach is outlined for the approximation of economically optimal design values of the failure probabilities along dyke-ring segments, which are treated as a series system of flood defences. The approach can assist in the determination of new protection standards in the Netherlands, but also in the design of flood prevention systems elsewhere.Hydraulic EngineeringCivil Engineering and Geoscience

Rationalization of safety factors for breakwater design in hurricane-prone areas

This paper presents the development of a semi-probabilistic method for armour layer design of rubble mound breakwaters, which is based on the use of safety factors. The objective is to introduce an approach that is both attractive to designers and sufficiently reliable when a high degree of uncertainty is involved in the design process. The main focus of the analysis is the calibration and appropriate use of the safety factors, which is the key element for a reliable result.Hydraulic EngineeringCivil Engineering and Geoscience

Probabilistic design of breakwaters in shallow hurricane-prone areas

One of the failure mechanisms of a rubble mound breakwater is the failure of its armour layer. In order to determine the stability of an armour layer, the design load has to be defined, which is in fact the wave that attacks the structure. Being a highly stochastic phenomenon, the wave action is not easily defined, while there is always some uncertainty inherent to its definition. In a deterministic calculation this uncertainty is being left to engineering judgment, as the possible variations of the design wave height are not taken into account in a coherent way. In order to explicitly incorporate uncertainties into the design process, and therefore increase its reliability, probabilistic design methods should be applied. A commonly used approach is a semi-probabilistic computation, which introduces the application of partial safety coefficients. Nevertheless the indicated methods to derive and apply them do not clarify the uncertainties incorporated, adding an undefined degree of safety in the process, or end up with incorrect results under certain conditions. Another approach is a fully probabilistic computation. This type of design tackles explicitly a great deal of uncertainties, hence its results can be considered much more accurate. However it is not commonly used, due to the fact that there are not straightforward guidelines to support it, and therefore a number of critical decisions by the designers are required. This paper focuses on the application of probabilistic methods for armour layer design of rubble mound breakwaters. The main objective is to indicate the weaknesses of the previously mentioned methods, and to suggest a probabilistic design approach that is both attractive to designers and sufficiently reliable. This can be achieved through elaboration of a design example with the various methods, followed by a critical evaluation of the results.Hydraulic EngineeringCivil Engineering and Geoscience