The joint impact of storm surge, fluvial flood and operation of man-made structures on the high water level frequency in the Lower Rhine Delta

Most deltas of the world and their highly urbanized environments, are vulnerable to flooding, and thus, the consequences in terms of human fatalities and economic losses are serious. Floods and the consequent damages have triggered significant developments of flood protection measures. Flood risk is expected to be much more serious in the future. On the one hand, climate change is exacerbating mean sea level rise and intensifying extreme river floods, consequently increasing high water level frequency. On the other hand, deltas are rapidly experiencing urbanization, which results in increasing vulnerability of deltas. High water levels in deltas are the result of interaction between natural flood sources (high astronomical tides, storm surges, river flooding, high intensive precipitation, or combination of more than one variable) and human interventions (flood control measures to reduce flood sources). In this thesis the joint impact of storm surges, fluvial floods as well as the operational water management system on the high water level frequency is estimated in the Lower Rhine Delta. A fully probabilistic approach is developed for resampling extreme hydrodynamic boundary conditions of the Lower Rhine Delta as well as the time revolution. The first application of a joint probability approach in the Lower Rhine Delta dated back to 1969 (Van der Made, 1969). It only considered the peak values of the sea level and the Rhine flow, assuming the other associated variables (such as the storm surge duration) to be pre-determined as constant values. Nevertheless, at present these associated variables play an important role in determining the water level in the delta. For example, the Maeslant barrier and the Haringvliet Dam with sluices should be closed when a storm surge occurs. A storm surge duration can affect the closure duration of the Lower Rhine Delta and therefore can influence the water level in the inland delta. In the fully probabilistic approach these associated variables will be taken into account. In the fully probabilistic approach, joint probability distributions of extreme hydraulic load variables derived from the observed flood events are applied to re-sample a large number of scenarios of storm surges, Rhine floods as well as Meuse floods. These scenarios drive a deterministic model to result in water levels at the locations of interest. These water levels can be converted into high water level frequency at locations. This approach enables assessment of the high water level frequency in a changing environment with associated effects from climate change and human interventions. In the Lower Rhine Delta, the impact of climate change on the high water level frequency is also quantified for the year 2050 in order to assist in decisions regarding the adaptation of the operational water management system and the flood defense system. To protect the Lower Rhine Delta from flooding, one of critical measures is to reduce the high water level frequency by taking advantage of the present operational water management system. This system refers to the man-made structures, such as large sluices, storm surge barriers and pumps, either at the mouth of the delta or along the rivers and canals, as well as their operational controls. This system is applied to control the water levels and flows within the delta for the aims (1) avoiding high water levels (due to high river discharges or storm surges or the combination of both), (2) avoiding low water levels (in case that problems with regard to freshwater supply and navigation) (van Overloop, 2009; 2011). The Dutch policy primarily aimed at the prevention of flooding by means of strengthening and heightening dikes, and therefore little attention has been given to the potential reduction of the high water level frequency as a result of developments of the operational water management system. In this thesis, the effect of the present and future operational water management system on the high water level frequency will be discussed. Construction of new structures such as storm surge barriers, flood gates has been proposed to improve the operational water management system for a better performance of high water level frequency reduction. In this thesis the effect of new structures on the high water level frequency is presented. The traditional approach applied only a very limited number of sampling scenarios (Mantz and Wakeling, 1979; Samuels and Burt, 2002) to the high water level frequency estimation with a detailed model. Computational burden for the usage of detailed models strongly limits the number of stochastic scenarios. However, a large number of stochastic scenarios are necessary not only for the statistical uncertainty reduction, but also for the present operational water management system controlling different extreme hydrodynamic boundary conditions. It requires unaffordable computational resource with a detailed model. Therefore, a simplified model derived from a detailed model is necessary. The particular contribution of this thesis is that it introduces a fully probabilistic approach for stochastic simulation of extreme hydrodynamic boundary conditions of the Rhine Delta. The approach takes the probability related to time evolution into account, and drives a deterministic model to estimate the high water level frequency based on the importance sampling Monte Carlo method. The impact of climate change and developments in the operational water management system is assessed. The approach can also be extended to the assessment of the flood probability and the flood risk in order to assist the flood risk management in the Lower Rhine Delta. This approach can also be applied to other deltas all over the world.Hydraulic EngineeringCivil Engineering and Geoscience

A joint probability approach using a 1-D hydrodynamic model for estimating high water level frequencies in the Lower Rhine Delta

The Lower Rhine Delta, a transitional area between the River Rhine and Meuse and the North Sea, is at risk of flooding induced by infrequent events of a storm surge or upstream flooding, or by more infrequent events of a combination of both. A joint probability analysis of the astronomical tide, the wind induced storm surge, the Rhine flow and the Meuse flow at the boundaries is established in order to produce the joint probability distribution of potential flood events. Three individual joint probability distributions are established corresponding to three potential flooding causes: storm surges and normal Rhine discharges, normal sea levels and high Rhine discharges, and storm surges and high Rhine discharges. For each category, its corresponding joint probability distribution is applied, in order to stochastically simulate a large number of scenarios. These scenarios can be used as inputs to a deterministic 1-D hydrodynamic model in order to estimate the high water level frequency curves at the transitional locations. The results present the exceedance probability of the present design water level for the economically important cities of Rotterdam and Dordrecht. The calculated exceedance probability is evaluated and compared to the governmental norm. Moreover, the impact of climate change on the high water level frequency curves is quantified for the year 2050 in order to assist in decisions regarding the adaptation of the operational water management system and the flood defense system.Hydraulic EngineeringCivil Engineering and Geoscience

The Effect of Four New Floodgates on the Flood Frequency in the Dutch Lower Rhine Delta

The Dutch Lower Rhine Delta, a transitional area between the Rivers Rhine, Meuse and the North Sea, is at risk of flooding induced by infrequent events of storm surges or fluvial floods, or the combination of both. To protect the delta from storm surges, it can be closed off from the sea by large dams and controllable storm surge barriers. Also, along the branches of the rivers controllable floodgates are operated to regulate the fluvial discharge. A former study quantified the flood frequency derived from three different sources that potentially may cause a flood and indicated that high water levels was mainly caused by the simultaneous occurrence of storm surges and Rhine floods. In the present water operational management system, the Haringvliet gates and the Maeslant Storm Surge Barrier with the Hartel Storm Surge Barrier should be closed in time when the simultaneous extreme event occurs, and therefore the extreme fluvial flow that accumulates during the closure would result in a very high water level within the delta area. Moreover, this frequency will increase significantly in the context of climate change. As a suggested adaptation measure, a controllable floodgate is proposed in Pannerdensch Canal and the other three floodgates in Merwede, Drechtse Kil and Spui are designed in the East and South of Rotterdam and Dordrecht. These floodgates are expected to decrease the potential extreme water levels which are driven by the simultaneous extreme events. This study will investigate the operational management of these four gates, and further apply a large number of scenarios of the simultaneous extreme event to estimate the effect on the flood frequency in the delta. The results can assist to make better decisions in the adaptation of the present operational water management system.Hydraulic EngineeringCivil Engineering and Geoscience

Influence of a storm surge barrier’s operation on the flood frequency in the Rhine Delta area

The Rhine River Delta is crucial to the Dutch economy. The Maeslant barrier was built in 1997 to protect the Rhine estuary, with the city and port of Rotterdam, from storm surges. This research takes a simple approach to quantify the influence of the Maeslant storm surge barrier on design water levels behind the barrier. The dikes in the area are supposed to be able to withstand these levels. Equal Level Curves approach is used to calculate the Rotterdam water levels by using Rhine discharges and sea water levels as input. Their joint probability function generates the occurrence frequency of a certain combination that will lead to a certain high water level in Rotterdam. The results show that the flood frequency in Rotterdam is reduced effectively with the controlled barrier in current and in future scenarios influenced by climate change. In addition, an investigation of the sensitivity of the operational parameters suggests that there is a negligible influence on the high water level frequency when the decision closing water level for the barrier is set higher due to the benefits of navigation (but not exceeding the design safety level 4 m MSL).Hydraulic EngineeringCivil Engineering and Geoscience

SensiBlend: Sensing Blended Experiences in Professional and Social Contexts

Unlike traditional workshops, SensiBlend is a living experiment about the future of remote, hybrid, and blended experiences within professional and other social contexts. The interplay of interpersonal relationships with tools and spaces—digital and physical—has been abruptly challenged and fundamentally altered as a result of the COVID-19 pandemic. With this meta-workshop, we seek to scrutinize and advance the role and impact of Ubiquitous Computing in the new “blended” social reality, and raise questions relating to the specific attributes of socio-technical experiences in the future organization of interpersonal relationships. How do we better equip people to deal with blended experiences? What dimensions of socio-technical experiences are at stake? To this end, we will utilize the occasion of a virtual UbiComp in combination with novel remote-working tools and participatory sensing with attendees to collectively examine, discuss, and elicit the potential routes of augmenting social practices in a discourse about the future of blended working, socializing, and living.Accepted Author ManuscriptHuman-Centred Artificial Intelligenc

A Looseness Detection Method for Railway Catenary Fasteners based on Reinforcement Learning Refined Localization

Brace sleeve (BS) fasteners, i.e., nut and bolt, are small components but play essential roles in fixing BS and cantilever in railway catenary system. They are commonly inspected by onboard cameras using computer vision to ensure the safety of railway operation. However, most BS fasteners cannot be directly localized because they are too small in the inspection images. Instead, the BS is first localized for detecting the BS fastener. This leads to a new problem that the localized BS boxes may not contain the complete BS fasteners due to low localization accuracy, making it infeasible to further diagnose the fastener conditions. To tackle this problem, this article proposes a novel pipeline for BS fastener looseness diagnosis. First, the competitive deep learning model Faster RCNN ResNet101 is used to coarsely localize BSs. Second, an action-driven reinforcement learning agent is adopted to refine the coarse-localized boxes through a dynamic position searching process. Then, BS fasteners are extracted from the refined localized BS image by the deep segmentation model YOLACT++, which is fast and interpretable. Finally, a looseness diagnosis criterion based on segmented information are proposed. We evaluate the performance of submodels independently and the overall performance of the whole model on a real-life catenary image dataset collected from a high-speed line in China. The test results show that the proposed method is effective for BS looseness detection in railway catenary.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.Railway Engineerin

Luminescence and site occupancy of Ce3+ in Ba2Ca(BO3)2

Applied Science

Reflecting on Hybrid Events: Learning from a Year of Hybrid Experiences

The COVID-19 pandemic led to a sudden shift to virtual work and events, with the last two years enabling an appropriated and rather simulated togetherness - the hybrid mode. As we return to in-person events, it is important to reflect on not only what we learned about technologies and social justice, but about the types of events we desire, and how to re-design them accordingly. This SIG aims to reflect on hybrid events and their execution: scaling them across sectors, communities, and industries; considering trade-offs when choosing technologies; studying best practices and defining measures of "success"for hybrid events; and finally, identifying and charting the wider social, ethical, and legal implications of hybrid formats. This SIG will consolidate these topics by inviting participants to collaboratively reflect on previous hybrid experiences and what can be learned from them.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.Human-Centred Artificial Intelligenc

G-jitter effects on half floating-zone convection in intermediate-frequency range

The g-jitter influence on thermocapillary convection and critical Marangoni number in a liquid bridge of half-floating rone was discussed in the low frequency range of 0.4 to 1.5 Hz in a previous paper. This paper extended the experiments to the intermediate frequency range of 2 to 18 Hz, which htrs often been recorded as vibration environment of spacecrafts. The experiment was completed on the deck of a vibration machine, which gave a periodical applied acceleration to simulate the effects of g-jitter. The experimental results in the intermediate frequency range are different from that in the low frequency range. The velocity field and the shape of the free surface have periodical fluctuations in response to g-jitter. The amplitude of the periodical varying part of the temperature response decreases obviously with increasing frequency of g-jitter and vanishes almost when the frequency of g-jitter is high enough. The critical Marangoni number is defined to describe the transition from a periodical convection in response to g-jitter to an oscillatory convection due to internal instability, and will increase with increasing g-jitter frequency. According to the spectral analysis, it can be found that the oscillatory part of temperature is a superposition of two harmonic waves if the Marangoni number is larger than a critical value

The scientific project of the small satellite of china

The efforts involved in developing a small satellite for scientific purposes in China in recent years are introduced in the present paper. The project is arranged on a case to case principle depending upon requirements and financial support. The space technology of a satellite and rockets, which have been developed over a relatively longer period in China, have been transferred to the scientific research of small satellites for improvement of the quality requirements. The surplus payloads of the rocket and satellite are used as the payloads of the small satellite and scientific experiments at a low cost. As an example, the project of balloon satellites for atmospheric research was successfully completed in 1991. The experience of the project management is of great benefit for further organization and arrangement of other projects. Opportunities exist for surplus payloads to be used in the future, and a small satellite for magnetospheric research will be launched in 1993