The energy market is growing and noise regulations for offshore foundation pile installation grow stricter. New initiatives arise to comply with the ongoing developments in the field, such as the BLUE Piling Technology under development by IQIP. Its features are presented as reduced underwater noise levels during installation, which is attibuted to the lower pile wall vibrations caused during driving. In this thesis, the design and execution of a field test is described, identifying the most important differences in geotechnical aspects between a prototype Blue Piling hammer and a conventional impact hammer, the IQIP Hydrohammer S-30. The results show that the Blue Piling hammer creates a response between pile and soil that is very different from a conventional impact hammer. The fundamentally different soil response led to pile plugging during the field test, affecting the stresses around the pile tip. This phenomenon is unlikely to occur during monopile installation, but scaling the test results requires further research.

This research aims to improve the current knowledge and insight into the construction process, logistics, and construction costs associated with the offshore pumped storage hydropower plant. The main objective is to enhance the construction costs by optimizing the work method based on these sheltering effects. The diffraction and sheltering effects due to the caisson dam will be determined using the Goda diffraction tables. Additionally, the Levelised Cost of Storage (LCOS) will be used to assess the cost-effectiveness of this bulk energy storage technology and enables the comparison with alternatives, such as lithium-ion and hydrogen storage. In summary, this research addresses the promising potentials of work method optimization for offshore caisson projects regarding the local wave climate. For a case study in the North Sea, it has not only highlighted the relevance and importance of including wave sheltering. Moreover, with a LCOS of € 140-260/MWh it also shows the competitiveness of the offshore pumped storage hydropower concept once again. Alternative energy storage methods such as lithium-ion or hydrogen are in the range of € 200-400/MWh for lithium-ion and € 200-1900/MWh for hydrogen storage. Therefore, offshore pumped storage hydropower (PSH) can be a favorable solution enhancing the energy transition.

The study delves into the crucial role of undrained shear strength in the stability of civil engineering projects involving soft soils. It explores the enhancement of this strength through (pre)loading in conjunction with Prefabricated Vertical Drains (PVDs). The Stress History and Normalized Soil Engineering Properties (SHANSEP) framework is employed to forecast changes in strength across various phases - before, during, and after loading. Validation is conducted using Cone Penetration Tests with pore pressure measurements (CPTu), and the Nkt strength factor is employed to correlate CPTu data with undrained shear strength. The research combines laboratory experiments and field data to predict undrained shear strength via SHANSEP, which is subsequently validated through CPTu measurements and monitoring. Two distinct datasets are examined in the study. The first dataset involves dike projects at 'de Markermeerdijken' in the Netherlands, where PVD-assisted surcharges of 5 meters are implemented. SHANSEP is utilized to predict strength levels before surcharge, post-surcharge removal (after >90% consolidation), and post-removal phases. These predictions are cross-validated using CPTu data and laboratory tests. The second dataset focuses on a reclamation project involving Marine Soft Clay strength in the Philippines. Strength correlations with CPTu tests during consolidation are established, and comparisons are made with data from piezometers and SHANSEP predictions. The analysis uncovers that SHANSEP's precision is contingent on several factors: 1. The uncertainty surrounding Pre Overburden pressure (POP), leading to inaccuracies in initial strength predictions. 2. The effectiveness of preloading being compromised by limited load area relative to depth. 3. Submergence of the surcharge beneath the phreatic surface, resulting in diminished preload and gained strength. 4. Incorporating creep into predictions necessitates a reduction in SHANSEP's S factor. 5. Accurate predictions rely on high-quality laboratory tests. SHANSEP demonstrates its ability to effectively forecast undrained shear strength in soft soils, with its predicted surcharge strength increments aligning with CPTu values. However, challenges are identified in predicting and verifying strength during consolidation due to the dominating influence of excess pore pressure. The study's key findings recommend the inclusion of adjustments for preload submersion, consideration of load distribution, and the evaluation of partially drained CPTu data using parameters such as Bq and qt to enhance the verification of SHANSEP-predicted strengths. The study emphasizes caution against relying solely on CPTu or piezometer data for ensuring reliability and accuracy.

An extensive Life Cycle Analysis (LCA) is used to determine the efficiency in reducing the carbon footprint of a graving dock. Firstly by identifying the hotspots in a base design, and then by comparing the various design alternatives. The focus is on reducing the amount of reinforced concrete used in the design of the dock floor by adding fibres to the concrete mixture and on prevention of having to dispose of in-flowing sediment after every docking procedure. Other evaluation methods such as a Cost Benefit Analysis (CBA) that compares the economic viability and a Multi Criteria Analysis that combines the results of the LCA and CBA and assesses the design alternatives on other criteria such as ease of operation and maintenance are used to determine the optimal dock configuration for Damen Shipyard and Conversion B.V. in Harlingen.

The inner-city of Amsterdam contains a large network of vulnerable, historic quay walls. Most of these quay walls consist out of masonry gravity walls placed on wooden relieving floors and wooden foundation piles. Due to the changing surface loading conditions behind the wall and the degradation of the masonry and wooden structures over the last century, the safety of the quay walls is in critical condition. Insight into the behaviour of the masonry wall tilt and its relationship with several failure mechanisms is still limited. Therefore, the objective of this thesis is to provide this insight into the behaviour of the tilt approaching failure in the center of Amsterdam. Additionally, the use of monitoring data from SmartBrick devices is analyzed to assess the value of quay wall inclination monitoring. Using PLAXIS 2D, quay wall models are made aimed to create a sensitivity analysis towards the wall tilt using multiple variations in quay structure dimensions and parameters. These variations investigate the wall height, wall thickness, floor length (and the amount of pile rows), the canal depth and the pile diameters based on a typical Amsterdam soil profile. For the tested geometry variations, there is a linear relationship seen between the wall tilt and the horizontal wall displacement towards the canal, during the addition of the surcharge load behind the wall. The relationship between the wall tilt and the surcharge load is predominately linear at lower/realistic surface loads, at higher loads, towards failure, the wall tilt becomes exponentially larger, this is also seen by setting the varied dimensions towards failure scenarios. The most sensitive variations for inclination are the change in the masonry wall height and thickness, the pile distribution underneath the floor and the addition of a surcharge load directly behind the masonry wall. The failure mechanism describing the horizontal displacement of the masonry wall and the piles is recognized by increasing the height of the masonry wall and by decreasing the pile diameters (pile degradation). By increasing the wall height, the quay structure also settles vertically, which in combination with the horizontal displacement, initiates wall tilt. During the addition of the surcharge load, the crossbeam (kesp) and the piles can deform, and their bending moments can exceed their bending capacity, indicating another failure mechanism with initiates wall tilt. The failure mechanism describing rotation of the masonry wall on the floor towards the canal is activated by decreasing the wall thickness and therefore decreasing its lateral capacity. This causes the masonry wall to fall over. Damage to the foundation elements has an important impact on the tilt of the wall, due extensive axial displacements of the front pile row or cracks in the masonry wall. To compare the SmartBrick inclination and PLAXIS inclination, it is important to know the exact degradation, erosion and loading conditions during the time between two SmartBrick measurements. The linear relation between the wall inclination and the wall displacement is useful for SmartBrick because it shows that monitoring the inclination also predicts the wall displacement and the state of the quay wall. Pile degradation and canal erosion only give a small wall tilt increase, but a larger increase in horizontal displacement of the wall is seen. Therefore, high measuring accuracy and resolution are necessary to monitor only the wall tilt. To conclude, approaching quay wall failure shows that wall tilt in combination with horizontal displacement is expected, this behaviour can be monitored using SmartBrick. High wall tilt is often a first consequence of the exceedance of the bending capacities in the wooden elements.

Large parts of the Netherlands lay below mean sea level. An extensive network of flood protection measures is in place to prevent flooding. Periodic safety assessment and reinforcement are required to guarantee a resilient system. Currently, in the Netherlands, an extensive sea dike reinforcement program is underway to meet the safety standards mandated by the Dutch government. A dike reinforcement project encompasses several components, often interacting with each other. This study focuses on the outer dike revetment. Traditionally, the revetment design is optimised for financial costs. This study aims to optimise the dike revetment design for the lowest Environmental Cost Indicator (ECI). This quantifies the carbon dioxide equivalent emissions generated throughout the entire life cycle of a construction project or its constituent parts. This is pertinent in the current context as the Dutch Government harbors ambitions of achieving a fully circular economy by 2050, with an interim goal of a 50% circular economy by 2030. This ambition is to be implemented by companies within their organization. The revetment is optimised as a whole by assessing the entire outer revetment and applying different types of revetment based on their probability of failure. The primary objective of this study is to acquire knowledge on designing a dike revetment that fulfils technical requirements and has the lowest environmental cost indicator possible. The revetment types to study are loose rock, concrete elements (Basalton), interlocking elements (Verkalit), hydraulic asphalt concrete and grass. The following main research question is defined: "What sea dike revetment design fulfils safety requirements and has the lowest environmental impact for the Lauwersmeerdijk-Vierhuizergat dike reinforcement project?" To answer this question, a Python-based model was made. The model evaluates the probability of failure of each design option and calculates the corresponding ECI and financial costs. The LauwersmeerdijkVierhuizergat project, a Waddenzee dike reinforcement, is used as a case study. The required safety level for the Lauwersmeerdijk-Vierhuizergat outer revetment is 1/60.000 years. The model requires input for the design equations. The input consists of decision variables, control variables and hydraulic boundary conditions. The decision variables are the variables in the design equations that the designer can alter. The control variables are the variables to which the designer has no influence. The hydraulic boundary conditions are determined for each water level discretised in steps of 0.2m. Next to the input for the probabilistic calculation, the input for the ECI and financial costs are required. The ECI data is obtained from the ’Milieudatabase’ (Schipper et al., 2022). The financial cost data is obtained from cost experts from Arcadis. For loose rock, the probability of failure is calculated with the equations as defined by van der Meer (1988a). For the placed elements, the probability of failure is calculated with the equation defined by Klein Breteler and Mourik (2014). The asphalt revetment is designed with the uplift and wave impact equations as defined in TAW (2002). The grass revetment is designed with the use of the ’Gras erosie buitentalud’ (GEBU) tool. The equations for erosion according to Klein Breteler (2022a) are included in this tool. The design equations are evaluated using crude Monte Carlo analysis for each water level with corresponding hydraulic boundary conditions, decision parameters, and control parameters. More than 2,000 designs, each meeting safety requirements, are made with varying transition heights. The optimal sea dike revetment design for environmental impact is the design with the lowest ECI score. When the probabilistic approach is applied, this design has loose rock revetment at the lower section, Basalton for the middle section, and grass for the upper section. In general, it is concluded that loose rock contributes most to the ECI and should be limited as much as possible. The middle section is traditionally made of hydraulic asphalt concrete. However, when replacing this with placed elements, a lower ECI is achieved. The grass revetment often requires large volumes of high-quality clay from external locations, requiring long transport distances. This results in high ECI costs for thick clay layers. When comparing the revetment with the lowest ECI to the revetment design with the lowest financial costs, it is concluded that the design with the lowest financial costs has a large section with hydraulic asphalt concrete instead of placed elements. The study design costs €1890 per meter, with an ECI of €373 per meter. The financially most attractive design costs €1439 per meter, with an ECI of €458 per meter. The difference in financial costs is €451 per meter (24%) and €85 per meter ECI costs (23%). For the revetment design made by Arcadis, deterministic and semi-probabilistic calculation methods are applied. The asphalt layer thickness is reduced by 50% when applying this method due to the large uncertainty in the probabilistic design. This results in a €12 per meter dike width lower ECI than the design with the lowest ECI made with the probabilistic approach. Thus, when designing a sea dike revetment probabilistically, aiming to reduce the ECI as much as possible, apply as little and the smallest possible loose rock grading, and replace the hydraulic asphalt concrete layer for placed elements.

Nature-Based Solutions (NBS) are increasingly gaining popularity due to their multifaceted benefits addressing various environmental and societal challenges for cities. The pursuit of achieving sustainable urban water management and enhancing resilience and well-being has expanded the range of NBS applications considered useful. Currently, traditional sustainable urban drainage practices sit alongside urban vegetation, such as parks, street trees and green facades, to address specific urban challenges, all delivering different benefits and tradeoffs. This diversity of applicable NBS introduces a decision-making challenge: Choosing appropriate nature-based solutions for cities. To address this challenge, this thesis developed a framework to assist decision-makers in selecting a set of potential suitable nature-based solutions for urban areas. The tool combines a screening method with a multi-criteria analysis that integrates public preferences, benefits, and tradeoffs of NBS based on ecosystem service variables. The new methodology has been demonstrated in the city of Tam Ky, Vietnam. The case study results showed successful integration of public preferences, benefits, and tradeoffs of NBS based on ecosystem service variables in the selection process. Combining this data into a method to visually present rank scores allowed to holistically evaluate the performances of different NBS relative to each other. This output can aid decision-makers and planners in gaining a more holistic understanding of the importance of local ecosystem services, enabling to align potential suitable NBS with public wishes and needs, and selecting a set of potential suitable measures accordingly.

This research explores the frequent urban flooding problems typically experienced in South-East Asian cities. Heavy rainfall during the monsoon period in combination with rapid urbanisation in the past decades causes an increasing amount of inundation events in the case study area Hanoi. The damage caused by these floods results in major economic losses that affect local citizens as well as governmental authorities. Flood waters are often heavily polluted with sewer water, threatening public health and reducing the overall livability of Hanoi. In addition, inundated streets are difficult to navigate, and waves induced by vehicles can lead to dangerous situations for pedestrians and other road users. This research aims to have a better understanding of the failure mechanisms of Hanoi’s drainage system, and the risks associated with each mechanism. Since there is no standard methodology for probabilistic risk assessment of urban drainage systems, the methodology for levee assessment was adopted and adjusted to the field of urban drainage. This straight-forward method is transferable to other study areas and results in clear and comprehensive fault trees which are easily interpreted by drainage authorities. A combination of expert judgement, qualitative fieldwork and analysis of newspapers was used to obtain an overview of all failure mechanisms and presented in the form of a fault tree. To investigate the potential damage that could be done by each failure mechanism, a probabilistic risk assessment was done using the urban drainage modelling software PCSWMM, and the potential risk of each mechanism was quantified. For the mechanisms with an unacceptably high risk, potential solutions were proposed. Four failure mechanisms were found that pose an unacceptably high risk on the drainage system: increased catchment size, pipeline blockage, inaccessible drains, and design inaccuracies. Potential solutions are to incorporate Low Impact Development (LID) in the urban area such as green and blue roofs, infiltration trenches and rain barrels. This type of infrastructure reduces the hydraulic load on the drainage system by reducing the runoff peak. In this way, urbanisation goes hand in hand with preserving the natural flows. Other recommended solutions are to revise the cleaning schedule to make it more efficient, and raise awareness among local inhabitants to enlarge their role in the functioning of Hanoi’s drainage system.

The case study of the outer lock head of the New Terneuzen Lock is considered to investigate the behavior of the Boom Clay and to develop an automated method for improving the deformation predictions in a deep excavation format. The initiative to perform this study was the uncertainty in modeling the Boom Clay behavior during the design and the over-predictions of the combi wall deformations in the aftermath. The problem has been attributed to the constitutive soil model and soil properties used for that layer. In the context of this thesis a Python - PLAXIS application has been developed, which facilitates an iterative method to determine the real soil properties of the Boom Clay layer based on inclinometer measurements of the wall throughout the construction stages. The monitoring data present the reality; hence the safety factors had to be filtered out of the design for the comparison with them to be applicable. Therefore, the mean (most probable) soil properties have been recalculated, and the as-build external loads, aquifer heads, structural elements, and phasing have been deciphered to create the Mean model. Using the Mean model, the most appropriate constitutive model and drainage conditions for the Boom Clay are determined. It has been concluded that the Hardening Soil small strain is the most appropriate constitutive model. Using the Mean model as initial input and the constitutive model conclusions, an iterative process on the relevant soil properties has been conducted to reach ±10% convergence with the corresponding monitoring deformations. The Fine Tuned model uses the soil properties derived by the iterative method to represent reality with the highest accuracy and reaches, on average, 45 % more precision on the prediction of the deformation in comparison to the monitoring data than the Mean model. Using the Fine Tuned model, sensitivity analysis of the wall to Boom Clay’s soil properties is performed. It revealed that φ′ had the highest impact relative to the other properties. Scenarios with thinner Boom Clay layers have been tested due to the relevant wedging geometry it follows in the project location. Additionally, the Fine Tuned model has been used to improve the prediction of future stages with data derived from earlier monitoring. The example studied was able to improve the prediction by 87 % in comparison to the initial design. In comparing the Design model with the Fine Tuned model, a problem with the anchor wall behavior is discovered that is attributed to the inability of PLAXIS to consider the shaft friction of the anchor rods. The Fine Tuned model, in combination with the fixity solution, allowed for an improvement in deformation accuracy of up to 95 %. It is concluded that the actual design, despite over-predicting its deformations, produced a retaining wall validated by the Fine Tuned model. It is suggested that the Python Application should be used alongside the traditional designing process and in site engineering to reduce the risk by simulating the actual behavior and limits of the retaining wall.

After overtopping, the most common failure mechanism in the world that leads to a dike breach is the instability of the inner slope. Two stability calculations are required for the semi-probabilistic assessment of inner slope stability. One calculation is without significant overtopping and the other calculation is with significant overtopping whereby the dike is saturated. The semi-probabilistic assessment method with overtopping is prescribed in a KPR factsheet, but is not verified by calibration calculations or probabilistic calculations. After performing semi-probabilistic and probabilistic calculations at Jaarsveld-Vreeswijk (JAV) in the Netherlands, there is an inconsistency between the semi-probabilistic and probabilistic estimates of the reliability index for inner slope stability with overtopping. Semi-probabilistic and probabilistic calculations have been performed to gain more insight in the inconsistency between the semi-probabilistic and probabilistic estimates of the reliability index for inner slope stability with overtopping. Based on the results, it is recommended to perform a calibration study for inner slope stability with overtopping to obtain a better estimate of the failure probability based on semi-probabilistic calculations.

The sea level is rising, possibly by one meter, by the end of this century. The Netherlands is preparing for this scenario through Kennisprogramma Zeespiegelstijging (KP-ZSS). One of the goals is to determine the hydraulic effects of sea level rise (SLR) on the current system. For the flood risk analysis within KP-ZSS, the current strength of the flood defences needs to be described. A set of typology-defined fragility curves based on river dikes in river areas describes the current strength of all the primary flood defences in the Netherlands. However, it is unknown if these fragility curves are applicable to sea dikes due to shorter high water and differences in soil parameters in sea/tidal areas. The research described in this thesis aims to evaluate if site-specific fragility curves for sea dikes result in significantly different predictions of future reinforcement cost for sea dikes compared to the typology-defined fragility curves. The analysis is centred around three dike sections in trajectories 29-3, 30-3 and 32-4 in the Western Scheldt. Initially, an evaluation is conducted on the fragility curves related to the geotechnical failure mechanisms of macro-instability and backward erosion piping. Subsequently, the height requirement is taken into account during the cost calculation. The typology-defined fragility curves underestimate the strength of macro-stability in two out of three cases with a factor 104 and factor 102, while underestimating it for one section with a factor 105. For the piping failure mechanism the typology-definde fragility curves overestimate the strength in two out of the three cases with a factor 103 and factor 102, but underestimates it for one section with a factor 103. The pre-overburden pressure appeared to be the most important factor influencing the failure probability of the macro-stability failure mechanism, with higher occurring values for the sections in the Western Scheldt. The failure mechanism of piping was influenced most by the hydraulic conductivity, where the encountered soil in the Western Scheldt consisted of finer soils with lower hydraulic conductivity. From the results, it can be concluded that the use of site-specific fragility curves resulted in a decrease of 13% in net present value, averaging over all SLR scenarios for an analysis until 2200. Considering the most probable SLR scenario resulted in a 12% decrease. If the height requirement is included in the cost calculation, the use of site-specific fragility curves results in a 7% decrease in net present value on average and a 12% decrease for SLR scenario low. For the low SLR scenario, the cost of relocating the road infrastructure in and around the expansion zone of the dike is dominant. With increasing SLR scenarios, the increase in crest height becomes the most important factor, with the revetment the dominating factor cost-wise, leading to minimal differences in reinforcement cost between the fragility curve approaches.

This study aims to create a redevelopment plan for the riverfront of Rosario by proposing a new spatial plan. This redevelopment plan is based on four themes that fall in line with the vision of the municipality in order for the riverfront to reach its full potential. These four themes are accessibility, safety, innovation and sustainability which form the basis for the six initiatives. Aiming for an enhancement of port-city integration and possibly solve some of the technical and social problems the city is facing. To reduce the scale of this research, a smaller scope has been selected which starts from Parque España till Parque de la Arenera. Within this area an attempt will be made to investigate what initiatives are feasible and what value they add. It is proposed to carry out water hubs, the reuse of stranded boats and port elements, a port museum, tourist information boards, water taxis or -buses and the restoration of the riverbanks to also enhance the port-city integration whereof there is a lack of at the moment. To strengthen the initiatives technical feasibility is also performed to the project. It is recommended to further analyse the proposed solutions for enhancing port-city integration and perform a more detailed technical feasibility.

The Hai Phong region is undergoing transformative changes through a Masterplan aimed at enhancing financial stability and improving the quality of life for the local community. A significant component of this Masterplan involves the construction of two new port terminals close to the mangroves of Do Son, a small town southeast of Hai Phong. Mangroves are beneficial in multiple facets. They act as a natural barrier, protecting coastlines from erosion, storm surges, and tsunamis. Additionally, mangroves contribute to water quality by filtering pollutants and trapping sediments, improving overall aquatic ecosystems. Furthermore, they provide crucial habitat for various species, supporting biodiversity and serving as nurseries for many marine organisms that benefit the local community. This research investigates the potential implications of the Masterplan using the following research question: What are the potential effects of the Hai Phong Masterplan on the mangrove ecosystems and the local community? Conducted by a multidisciplinary team of six students, this research involved interviews with professionals, locals, and governmental organisations, extensive literature review, and field trips. It was concluded from this research that the construction of the port terminals have far-reaching consequences. In the mangrove area in Bang La (area A), the port terminal will have a sheltering effect over the mangrove area. This will cause sedimentation to occur and thus accretion. Also, it is also expected that the water quality will degrade further due to increased anthropogenic activity in combination with the poor sewage system present. The mangrove area in Ngoc Hai (area B) is expected to have little direct changes. The local community in Do Son shows varied awareness and support for the Masterplan, with stronger support in mangrove area A. Economic benefits, such as increased tourism, drive positive attitudes. However, there is a notable lack of awareness in area B. The willingness to participate is influenced by economic incentives, and effective communication is crucial for shaping community perspectives. With regards to the further execution of the Masterplan it is recommended to incorporate effective waste management, revise reafforestation plans to meet legal obligations, and engage key environmental stakeholders. For further research, it is recommended to conduct measurements over a more extended period of time to better understand the dynamics of the area. Additionally, more detailed research is needed to substantiate assumptions.

Sea level variations and storm surges are expected to increase as a result of climate change. 570 cities and some 800 million people are by 2050 estimated to be exposed to these phenomena when emissions do not decrease (UCCRN, 2018). It is, however, deeply uncertain if and to what extent emissions will decrease. Additionally, the effects of climate change are not fully understood due to its complexity, resulting in a wide range of uncertainty. Flood risk measures can be implemented to reduce flood risk. The economic evaluation of such measures is affected by other factors of uncertain nature such as economic growth. The Dynamic Adaptive Policy Pathways (DAPP) approach has been identified as an approach capable of identifying and implementing effective flood risk strategies under uncertain conditions (Haasnoot et al., 2013). This approach aims to provide decision-makers with insight into what action to take when. Simultaneously, the approach focuses on ensuring flexibility which facilitates adjustments to unforeseen conditions. Within this approach, so-called adaptation pathways need to be developed. These pathways describe a sequence of actions over time required to ensure a minimum level of flood safety. The DAPP approach has been applied to simplified cases in previous research, but not yet to more detailed master-planning for which the creation and economic evaluation of pathways is a not straightforward process. This results in the main research question of this thesis: How can the Dynamic Adaptive Policy Pathways (DAPP) approach be used to create and select effective flood risk strategies under highly uncertain conditions? This research question has been addressed by developing a framework capable of creating adaptation pathways and evaluating them with an incorporated scenario-based economic evaluation. This framework is supplemented with a probabilistic assessment that evaluates the performance of pathways in the full range of possible but uncertain futures. The use of these tools has afterwards been validated by applying them to a fictive case and a case study along the South East Coast of Singapore. The framework can be used to assess the sensitivity of uncertainties. Additionally, it can be used to obtain the conditions for which a different pathway turns out to be more effective. Damages corresponding to certain water levels are required as input and are used to build the damage function of a specific project area. These damages can be modelled with damage modules like the Global Flood Risk Tool (GFRT). The damage function and other basic information like dimensions and characteristics of the project area are used to perform an economic optimisation of individual measures. A selection of adaptation pathways (consisting of combinations of measures over time) is made based on prerequisites and a scenario-based evaluation. The scenario-based evaluation is supplemented with a probabilistic assessment as the use of scenarios might lead to cognitive biases and does not cover the full range of future possibilities (Hoffmann, 2017). This probabilistic assessment is conducted by means of a Monte Carlo simulation and can be used to evaluate the robustness of pathways in the full range of possible futures. A pathway can afterwards be selected and trigger values that should initiate the implementation of subsequent measures can be obtained via the framework. The developed method has first been applied to a fictive case. A small area with a standard damage function was assumed for this. After the framework had been validated, the input-conditions were altered to assess the individual influence of each uncertain input value. The outcome turned out to be dependent on the characteristics of the project area and the assumed conditions. An increased area resulted in a pathway with a flood wall instead of a landfill as first measure being most effective. Out of the uncertainties, the discount rate and socio-economic growth rate turned out to most significantly affect the Net Present Value (NPV) and Cost-Benefit Ratio (CBR) of flood risk strategies. Especially, low discount rates and high socio-economic growth rates resulted in pathways built up of individual measures with lifetimes exceeding the technical lifetime of measures. To prevent this, and to ensure a flexible approach, the lifetimes of individual measures were restricted. A flexible approach enables one to adjust to conditions other than those that have been assumed. Measures with a long lifetime ahead lead to bigger investment costs and these are irreversible when the conditions turn out to be less severe than anticipated. The contrary also turned out to be possible. These short lifetimes corresponding to measures with practically infeasible low heights were prevented by setting a minimum height at which the linear relationship between the height and costs of measures starts. The probabilistic assessment was conducted after a pathway was selected. Increasing the range of uncertainty for this pathway logically led to a wider range of possible outcomes. This wider range of outcomes can be a reason not to select a certain pathway as the probability of a low NPV is higher. The fact that this difference could not be observed in the outcome of the framework underlines the need for this probabilistic assessment. Finally, trigger values were set for the selected pathway of the fictive case. The trigger values were initially set for the planned subsequent measures. However, it could be observed that the obtained trigger value for the planned subsequent flood wall increment did not result in sufficient time to implement a storm surge barrier without dropping below the required minimum level of flood safety. Therefore, trigger values corresponding to the next planned subsequent measure could potentially lead to the exclusion of other possible subsequent measures. Instead of setting trigger values for the planned subsequent measures, trigger values should provide enough time for all possible subsequent measures to forestall the exclusion of possible measures and ensure flexibility. The findings from the fictive case led to adjustments of the framework to ensure practical feasibility and flexibility. The adjusted framework was afterwards applied to a real-life case along the South East Coast of Singapore characterised by a narrow water level distribution, i.e. a relatively small difference (∼15 centimeters) between water levels that differ a factor of 10 in return period. A storm surge barrier turned out to be a factor of 10 more costly than alternative solutions, irrespective of the assumed sea level rise scenario. Therefore, it was concluded that the storm surge barrier was not the desired flood risk reduction measure for the project area and the area was subdivided into smaller areas to further optimise the flood risk reduction strategy. The framework was used to create flood risk reduction strategies. No measures turned out to be required until 2092 for the assumed conditions. The sensitivity analysis of this case study showed that assuming a more severe sea level rise scenario (an additional 58 centimeters in 2100) and accounting for additional storm surge caused by climate change, could result in measures being required over 50 years earlier. Without taking this into account, two pathways turned out to satisfy the safety standards until 2200 for the assumed conditions. One pathway solely consists of a flood wall and subsequently flood wall increments (AP10) while dryproofing is the first measure of the other pathway and subsequently a flood wall and a flood wall increment are implemented (AP33). The costs of AP10 turned out to be slightly higher in the full range of futures than that of AP33 but the probability of obtaining a higher NPV than obtained from the framework was also higher (58% vs. 51% of the outcomes higher than the NPV of AP10 obtained in the framework). As the differences between the probabilistic assessments of the pathways are not substantial, the preferences of local stakeholders are even more important. Dryproofing can lead to inundation of the land for high water events with a return period lower than the safety standard while Singapore has set the goal to protect its coastlines and prevent inundation of the land. Therefore, the pathway consisting of a flood wall and flood wall increments turns out to be the most suitable solution for the project area. This research contributes to the existing knowledge related to the DAPP approach as it smooths the not straightforward process of creating and evaluating adaptation pathways under uncertain conditions. It showed how to economically optimise individual flood risk reduction measures and build adaptation pathways out of those measures. A framework has been developed to automate this process and instantly evaluate the effectiveness of such pathways for set conditions. This study also showed how a probabilistic assessment of these adaptation pathways could be used to select a robust flood risk strategy. This developed method can further be fine-tuned by including transfer costs that reflect the costs of maintaining flexibility in the face of deep uncertainty. Additionally, flexibility can be incorporated within the probabilistic assessment to enable alteration of type and/or height of subsequent measures for conditions different than assumed. This would result in a more accurate assessment. Automating the integration of the probabilistic assessment within the framework can eventually lead to one complete tool which enhances the applicability and allows for the probabilistic assessment of all pathways instead of just a selection of pathways.

The study of water is without question an important one. We can learn a lot by studying the theory but in the end, it is essential to actually go out into the field and see the hydrological processes in practice for ourselves. The educational value of fieldwork lies not only in seeing theory become reality but also in experiencing the difficulties and limitations of gathering data first-hand. The water resources department of the Hanoi University of Natural Resources and Environment (HUNRE) wanted to expand its curriculum with a fieldwork excursion that will be part of three courses related to surface water, groundwater, and water quality. During our ten weeks in Vietnam, we assisted the teaching staff of the Water Management faculty in the development of these courses. We selected multiple experiments and found suitable locations for their execution, about a three-hour drive from the university. Several times we visited the fieldwork site together with students and teachers to explore the catchment, perform experiments, and gather data. For every experiment, a comprehensive manual was written with accompanying assignments and sheets tailor-made for the fieldwork excursion. All manuals are combined into a practical document that can be brought into the field. The experiments require a wide variety of specific pieces of equipment. Most but not all of these were present at the university. With financial support from the Orange Knowledge Project (OKP), we were able to repair existing equipment and acquire new equipment that was lacking in order to facilitate the experiments that were deemed essential. We also re-organized part of the water lab where all equipment is stored to improve the equipment’s maintenance and organization. With the completion of this project, we believe to have made a contribution to the improvement of the quality of education at HUNRE. We hope that a lot of students can benefit from our efforts as they go on the fieldwork excursion in the coming years.

The Mekong Delta in Vietnam is facing several challenges as a result of climate change. Among others, the effects include an increase in river discharge during the wet season, leading to river floods, and a decrease in river discharge during the dry season. The decrease in discharge results in a shortage of fresh water required for irrigation and drinking water. Besides that, the combination of sea-level rise, land subsidence, and decreased river discharge during the dry season results in saltwater intrusion. This threatens freshwater supply even more. Furthermore, there is an increasing risk of floods from the sea due to low land elevation and the rising sea level in combination with the occurrence of storm surges. The scope of this research is the area around the Ham Luong estuary, which is a branch of the Mekong River. The partial closure of this river branch is considered by the Vietnamese government as a measure to reduce the effect of the above-mentioned effects of climate change. However, not enough research has been conducted yet on the impact of a partial closure on the Ham Luong estuary. This has lead to the following research question: “What is the impact of various closure scenarios on the hydraulic characteristics and social activities in the Ham Luong estuary, considering a 75-year forecast?” The region of the Ham Luong estuary is characterised by its intensive agri- and aquaculture. More than 60% of the inhabitants is directly active within the agri- or aquaculture. As these activities are strongly dependent on the salinity of the estuary, they are highly affected by the effects of climate change. The region is densely populated with more than 125,000 inhabitants living near the Ham Luong estuary. It is clear that the effects of climate change are threatening the region in hydraulic aspects, as well as socio-economic aspects. A partial closure could reduce these effects, but will influence the region in several ways. In order to estimate the impact, a combination of hydraulic and socio-economic aspects is assessed based on a criteria set. This criteria set contains the criteria of freshwater supply, agricultural and aquaculture adaptation, biodiversity, stable riverbanks, and navigability. These criteria will be tested on a total of four alternative interventions in the Ham Luong estuary. Three alternatives with a storm surge barrier and one alternative without a storm surge barrier. All alternatives include heightening of the existing dyke system, as this seems to be inevitable when aiming for long-term development in the region. The extend of dyke heightening is subject to the choice of alternative. As a part of the impact analysis, a Delft3D model was built to analyse the hydrodynamic and morphodynamic processes in the Ham Luong estuary. The model was restricted to the chosen spatial scope, which only covers the Ham Luong estuary, without any upstream bifurcations. The model gave insights in processes like salt intrusion, sedimentation rates, and water levels. However, due to model simplifications and assumptions, the outcomes of the model where not useful for quantitative assessments. Still, the results are used to compare the impact of the different alternatives to each other. As expected, the alternatives that include a storm surge barrier will provide more possibilities to retain fresh water than the alternative without a barrier. From the results, it followed that the limited spatial scope excludes the redistribution of upstream discharge. It is recommended to look at a larger scale of the Mekong Delta when assessing hydro- and morphodynamic processes. Forming a flood protection system, the structural design of such a storm surge barrier, together with a quick estimation of a dyke system. The dyke system is different for each alternative, depending on the presence and the location of a barrier. The barrier design includes a thorough analysis on feasibility of gate types, technical requirements, load combinations, design of dimensions, and the operation. The load combinations take hydrostatic, hydrodynamic, wind, and soil loads into account. The design of the dimensions is done for the gates, sill, lifting structure, pier, foundation, and the bed protection. By assessing the above-mentioned criteria, a preferred solution is identified. This preference is based on a Multi-Criteria Analysis, which includes weighted scores for all alternatives. The outcome of the Multi-Criteria Analysis appears to be very sensitive to the rating and weights of the criteria, which makes it difficult to identify one of the alternatives as the preferred solution based on only the score on the different criteria. For this reason more research is needed. However, when including a cost estimation of the four alternatives, it can be stated that the alternative of no storm surge barrier and only the corresponding extensive dyke heightening could be considered as most cost-beneficial alternative and therefore as the preferred solution. It is expected that with or without closure of the Ham Luong estuary the system will change. The availability of fresh water will be improved by the presence of a closure, although more research is needed to specify this further. The increasing salt intrusion, as a result of Relative Sea-Level Rise (RSLR) will lead to agricultural and aquaculture adaptation in all alternatives. Either due to the construction of the barrier, or due to the gradual RSLR. A closure also has effect on the biodiversity, stability of the river banks, and navigability in the river. When implementing a closure these effects should be further investigated to assess the effect quantitatively.

The Mekong Delta is facing some complicated challenges in the near future. Its geographical location and the fact that it is a delta result in low elevation levels which makes it vulnerable to inundation. This problem will only become bigger in the future due to the effects of climate change. To get funding from organisations like the world bank it is important to propose multiple solutions that are beneficial to multiple parts of society. It is favourable to split a complex system like the Mekong Delta into subsystems to make it more feasible to build realistic models. The subsystem defined in this report is the Hau River estuary. This area mainly suffers from riverine inundation caused by tidal variation in the South Chinese Sea. The biggest city in the region is Can Tho with 1.3 million inhabitants. The research question is: Which integrated solutions reduce riverine inundation problems in the Hau River estuary while also considering socio-economical aspects? To answer this research question the following four solutions are proposed and designed. • Discharge sluice in the mouth of the Hau River to reduce the tidal influence • Wetland with a double levee system and buffer zones to reduce peak discharge • Bypass channel to the Gulf of Thailand to reduce discharge during the wet season • Protection of valuable assets and adaptation of local citizens to the new natural balance Based on desired discharges and water levels preliminary design parameters of the proposed hydraulic structures were determined. The effectiveness of these solutions was assessed based on their ability to reduce the water level in Can Tho. The reduction that the discharge sluice achieved was determined with a zero-dimensional model, whereas the water level reduction that the wetlands and bypass option achieved were determined by Delft3D models. The discharge sluice performed best in reducing the water level in Can Tho, as it opposes the tidal influence in the Hau River. To assess the quality of the solutions relative to each other a best-worst multi-criteria analysis is done. In this assessment other factors such as financial aspects, socio-economics and transportation are taken into account. The most important criteria are flood reduction and funding opportunities. According to the assessed criteria, the discharge sluice and the wetland are the best-scoring solutions. These solutions have the most potential in reducing the river inundation problems in the Hau River estuary. This does not mean that the bypass and adaptation solutions should be neglected or are not useful. For a complex problem in a complex system like the Hau River estuary, one solution is not going to solve all the problems. A good balance between different aspects has to be determined by also considering other problems like sand mining, subsidence and salt intrusion.

In response to Amsterdam’s housing shortage, IJburg on the east side of Amsterdam, is being devel- oped. IJburg consists of six artificial islands in total on which about 20,000 homes for 50,000 residents are being built. Strandeiland (Beach island in English), located in the lake called IJmeer, is one of these artificial islands which is currently being developed to accommodate approximately 20,000 residents. This project aims to introduce approximately 8,000 homes. However, the establishment of Strandei- land presents hydraulic safety concerns, especially with the presence of extreme low water levels and fluctuations due to wind set-up and set-down. Strandeiland will feature an inland water with high recreational value for residents. This inland water will also provide access for recreational boating. Wind set-down and set-up can create extreme water level differences in this inner water. These water level differences are unfavorable and create danger to the stability of the island. These fluctuations pose a severe challenge to the stability and functionality of the island’s water infrastructure. Two primary solutions were evaluated: the adaptation of the inner quay wall or the implementation of a guard lock. Making the inner quay wall suitable for the water level differences brings several implications: • Restrictions on utilities: Because the inner quay wall would be marked as primary flood defence, no pipes and cables would be allowed inside the wall. • Design constraints: When the quay wall serves as the primary flood defence, construction on its inner slope and tree planting is prohibited. This would negatively impact the aesthetics of the waterfront and limit the housing construction space. • Increased height requirements: The inner wall has to be higher according to primary flood defence regulations, this would escalate construction costs. • Higher strength sheet piles: A higher strength of sheet piles has to be used to withstand ex- tremely low water levels which would also lead to escalating construction costs. Adapting the Inner Quay Wall, while feasible, introduces significant design and functional constraints. Because of these constraints, this option is less desirable and implementing a guard lock is the favor- able solution to solve the water level fluctuations. The guard lock as part of the primary flood defence controls extreme water level variations, ensuring Strandeiland’s water infrastructure’s integrity. The Guard Lock not only modifies the primary flood de- fence location, reducing its length considerably but also mitigates the constraints associated with an adapted inner quay wall. The water level spread is set from the program of requirements at NAP -0.6 meters and NAP +0.1. The current estimate is that this will require the lock to close 10 times a year, which is considered acceptable. A movable bridge is integrated which functions both as a neighbor- hood connector and a part of the beachside boulevard. The main objective during the design phase is to develop a Guard Lock concept for Strandeiland that facilitates the management of water level fluctuations while accounting for potential failure mechanisms. Dimensions for the Guard Lock were determined based on the standard vessel, leading to lock cham- bers measuring 22 meters in length and 7.6 meters in width. Anticipating approximately ten annual guard lock closures in extreme scenarios, the F/E system is not included initially. To facilitate a possi- ble future inclusion of a F/E system, the core dimensions are based on two lock chambers resulting in an overall structural length of 36.46 meters. Different gate designs were evaluated for the guard lock design: Mitre Gates, Rolling/Sliding gates, Lift gate (submersible), Lift gate (upward direction), Radial gates and Single-leaf gates. The first step was to check whether the different gate types were suitable for the situation in which Strandeiland is, looking at space and and vertical clearance. The lift gate in upward direction and the rolling sliding gate were considered unsuitable for this purpose. The elevator gate limits vertical clearance and the rolling sliding gates takes to much space besides to the lock. The remaining gate types were measured in a multi-criteria analysis, which resulted in a double set of mitre gates ensuring both-way retention. Because of safety and energy efficiency, but especially because of local knowledge and possibilities for maintenance, electromechanical driving mechanisms were chosen for the gates instead of an hydraulic driving mechanism. Key design elements of the core construction of the guard lock consist of the concrete structure con- sisting of the walls and the floor slab. After performing the stability checks for the bearing capacity, overturning and piping the strength calculations are done for the floor slab and the walls of the con- crete structure. The reinforcement calculations are providing detailed reinforcements for the floor slab and walls. The pile foundation is another main component of the structure. The vertical bearing capacity check indicates that no pile foundation is needed, but because non uniform settlement is expected a pile foun- dation will be included. Three different layers were evaluated to check which one was the best fit for the guard lock of Strandeiland. As the first layer is determined to be suitable to bear the load of the structure, this layer has been used. This is the most cost effective for the pile foundation design, as there is less material needed for the pile foundation design. The calculations show that 45 piles with an diameter of 0.8 m each satisfies the need to prevent non-uniform settlements under the structure. The last component which has been determined is the gate height. The process for determining gate height utilized Reliability-Based Design (RBD) principles. Reliability-Based Design (RBD) ensures the gate height is optimal in terms of cost and safety. In this way an effective design for the gate height is obtained. A comprehensive fault tree analysis, combined with a Monte Carlo analysis, established the final gate height at 5.05 meters corresponding to NAP + 1.55 m, as shown in Figure 1.