Ports face the dual challenge of keeping waterways navigable through continuous dredging while treating most dredged sediment as waste. Across Europe, only about 1% of the 200 million m³ dredged annually is put to beneficial use. This thesis addresses this challenge for the Port of Rotterdam, where offshore disposal remains the dominant practice because of its low cost and operational simplicity but provides no resource recovery and creates environmental impacts.

The research investigates whether participatory logistical modelling can support better decision-making on sediment reuse. An open-source simulation model (OpenCLSim) was developed to represent dredging, transport, and processing chains for three strategies: (1) continued offshore disposal, (2) land raising via truck or pipeline, and (3) reuse in concrete after dewatering. Stakeholders from the port authority, government agencies, contractors, and researchers were engaged through interviews, surveys, and workshops to co-define evaluation criteria and weigh their relative importance. Model results were combined with a multi-criteria decision analysis to rank alternatives.

Findings show that while offshore disposal remains the most cost- and time-efficient solution, pipeline-based land raising approaches cost parity at high volumes and delivers co-benefits for flood protection and habitat creation. Concrete reuse shows strong circular economy potential but is limited by dewatering costs, logistics, and regulatory barriers.

The study concludes that sediment management should be treated as a portfolio challenge, combining conventional disposal with targeted reuse projects. Participatory modelling proved valuable for exploring trade-offs, testing “what-if” scenarios, and building consensus—providing a transferable framework for more sustainable sediment management.

The development of hydrogen import value chains is considered essential to achieving long-term decarbonization goals in the Netherlands. Although the systemic complexity of international hydrogen trade is acknowledged in the literature, empirical research into the policy and governance aspects of these import chains remains limited in the Dutch context. This study examines the extent to which current Dutch and EU policy frameworks address the challenges associated with early-stage hydrogen import chains, drawing on case studies of the United Kingdom (non-EU, non-EEA) and Norway (non-EU, EEA).

A qualitative case study approach was employed, combining policy document analysis with 18 semi-structured stakeholder interviews from various sectors, including industry, infrastructure, research institutions, and government-affiliated organizations. The qualitative data were coded and analyzed using Atlas.ti, with categories of transition challenges based on the frameworks of Weber et al. (2012) and bolhuis (2024), which were used to structure the findings.

The analysis reveals a range of interdependent challenges, including regulatory complexity, infrastructure bottlenecks, limited financial support for ammonia cracking, and a lack of tailored safety frameworks. Nevertheless, some instruments, most notably H2Global and the RED III RFNBO mandates, are positively received by stakeholders and viewed as promising instruments to stimulate investment and demand. Their full potential, however, depends on timely implementation, increased scale, and improved alignment across national and European levels. Variation in national export contexts further shapes the character of the challenges: in the UK, regulatory divergence and uncertainty surrounding export subsidies are key constraints; in Norway, more substantial institutional alignment is offset by public concerns surrounding the use of ammonia.

Enhancing the current Dutch policy framework through an updated national import strategy, robust and clear demand articulation, infrastructure development, and targeted policy for green ammonia imports would improve investor confidence and facilitate the timely development of international hydrogen import chains.

In a rapidly evolving industry, Van Oord, a leader in marine engineering and offshore energy, seeks to better align its strategic objectives with operations to drive innovation and achieve sustainability targets. The company faces challenges in aligning goals across departments in complex, multi-stakeholder projects. While Objectives and Key Results (OKRs) present a promising goal-setting framework, implementing OKRs in an asset-based, project-driven organization like Van Oord is challenging due to the need for interdepartmental alignment, clear accountability, and strategic coherence. There are examples of this method being introduced in technology driven organizations, but a direct comparison to a marine engineering contractor is not found. The study has used qualitative methods, including a systematic literature review and a case study consisting of three use cases at Van Oord, examining OKR implementation through interviews, observations, personal communications and online documentation. Findings show that OKRs are widely seen as a promising tool for improving goal visibility, alignment, and cross-departmental collaboration, especially in innovation-focused teams. However, their feasibility depends on careful adaptation to existing reporting systems, team autonomy, and time constraints. The thesis concludes that OKRs can add clear value when introduced incrementally, with team-led pilots and integration into existing planning rhythms. The study contributes to both theory and practice by offering design recommendations for OKR adoption in complex engineering organizations and identifies areas for future research, including the integration of OKRs with sustainability metrics and long-term strategic planning.

Global food security is under increasing pressure due to climate change-induced environmental stressors: salinization, droughts, and waterlogging (SDAW). These stressors are already causing economic losses, environmental degradation, and societal problems. One promising adaptation strategy involves the transition to more resilient agricultural systems based on crop selection and management, referred to in this study as Salt-Resilient Agricultural Systems (SRAS). However, current knowledge about SRAS transitions is often based on single aspects, limited in scope, and mostly focused on global scales.
A practical spatial approach is needed that combines SRAS knowledge with local data, helping decision-makers understand which SRAS options are feasible, where they are suitable, and what their implementation implies for key stakeholders. This was achieved by answering the question: ‘Which salt-resilient agricultural systems are potentially suitable for areas increasingly affected by salinization, drought, and waterlogging, and how can their spatial suitability be assessed and interpreted based on soil types and climate projections?’
To address this question, the case study Schouwen-Duiveland was investigated, because this region is already exposed to SDAW stressors. Both current conditions and a high 2050 climate scenario were assessed. This desk study developed a spatial suitability framework to evaluate the potential of SRAS based on four key factors: salinity levels, drought stress, waterlogging stress, and soil type.
Through a combination of literature review and geospatial analysing in QGIS, three promising SRAS approaches were identified for Schouwen-Duiveland. These include: 1.) Salt-tolerant crop rotation, which adapts conventional agricultural practices to include crops with higher salinity tolerance. 2.) Halophyte (plants that thrive on saline soils) intercropping or rotation, which can improve soil health by taking up salt from the soil while enabling cultivation of conventional crops. 3.) Agroforestry, a system based on trees or shrubs, which provides a higher tolerance to both drought and waterlogging, while also increasing biodiversity and potentially total yields.
Due to several data and knowledge gaps, assumptions had to be made, which reduce the robustness of the outcomes. Therefore, this study should be seen as an exploratory assessment rather than a set of definitive guidelines. Nevertheless, the results highlight the potential of these systems and emphasize the need for sustainable water management and location-specific guidelines, considering the local variability of stressors.
The spatial suitability maps were interpreted from both scientific and societal perspectives and are recognized as a tool to initiate social dialogue around the SRAS transition. These spatial guidelines can serve as practical tools for both policymakers and farmers.
Achieving a full transition requires increasing the readiness for change, starting with small-scale field experiments initiated by farmers, supported by policymakers who share the risks. Other key aspects include collaboration and knowledge sharing between stakeholders, which are essential for gaining further insights and improving spatial suitability assessment.
Despite its limitations, this study provides a foundation for a practical tool to assess local SRAS suitability. It contributes to informed discussions for SRAS transitions and ultimately supports the development of climate-resilient agriculture that strengthens long-term food security.

Multiple challenges affect the effectiveness of climate change mitigation and adaptation measures, such as accountability, intergenerational justice and developing countries’ increased participation in greenhouse gas emissions. The high complexity of information surrounding models’ assumptions, results, and scenarios related to climate change also presents a challenge, especially when communicating with policymakers. In this context, support tools such as policy platforms can help bridge the science-policy gap by allowing policymakers to understand scenarios and available policy levers, enabling a better understanding of relevant concepts and models or serving as hubs for disseminating best practices and success stories. Available literature often evaluates support tools within the context of use by regular citizens, making it unclear how policymakers perceive support tools and how well they meet their needs, pointing to an important knowledge gap. This thesis explores policymakers’ and policy advisors’ perceptions of the usefulness of climate change mitigation and adaptation (CCMA) policy platforms and the characteristics of such policy platforms they prefer in order to use them as support tools. A collective case study was conducted with ten CCMA policy platforms within the context of the EU-funded Horizon 2020 programme. In addition, interviews (11) and surveys (9) with policymakers and policymakers’ advisors in the Netherlands and seven other countries within and beyond the EU were conducted.

Nine characteristics of CCMA policy platforms were identified: Transparency & Credibility of information, Ease of use, Flexibility of use, Accessibility & Portability, Education & Awareness, Communication of complex information, Data visualisation & interactivity, Actively maintained and supported, and Security & privacy. Interviews and surveys show that accessibility, relevance, applicability, and credibility were identified as the primary factors driving the perception of policymakers about the usefulness of CCMA policy platforms and four groups of characteristics were identified with decreasing levels of priority for policymakers: mandatory or must-have (formed by communication of complex information, free and open access to the tool, transparency regarding data sources and limitations, and high level of detail for spatial and temporal data); highly desirable or should-have (formed by availability of training and learning functionalities, availability of detailed documentation on concepts and models, interactive and easy-to-navigate elements, and availability of a web-based platform); ‘nice to have’ or could-have (user stories from policymakers or communities, availability of very recent data, ability to import user data/export results, and ability to modify parameters and run custom analyses), and indifferent (availability of languages beyond English and the ability to use the tool in mobile phones or tablets).

Four main recommendations are made to improve the design and use of CCMA policy platforms: Incorporating systematic reviews of existing CCMA policy platforms as part of projects developing such platforms, involving boundary organisations in the development and use of CCMA policy platforms, developing CCMA policy platforms with longer life expectancies and developing CCMA policy platforms flexible for different needs and preferences of policymakers.

With these results, new CCMA policy platforms can be developed with a better understanding of how useful policymakers perceive them and what they want from these support tools.

Over the years, the marine contracting sector has faced many challenges surrounding safety, the economic fluctuations because of the oil crisis and now tackling the sustainability challenge. Years of experience in the offshore industry, a heavy industry that contributes significantly to the climate crisis through its environmental impact, is deemed to change its strategy and way of working. However, this challenge is relatively new and asks for a new approach to move along with the fast-changing requirements of clients and external regulations that can have financial consequences if one is not acting now. Engineering solutions to reduce and prevent impact are already aligned, thinking of shore power, carbon capture and storage techniques, and alternative fuels on the vessels. Nevertheless, the total environmental impact goes beyond the implementation of these technologies. Making a change on the total impact of a marine contractor asks for a behavioural change within the organization, towards decision-making taking care of the environment. Finding a balance in actions that lead to investing in sustainable technologies and setting every employee to actions that flourish within to contribute to the company's sustainability ambitions will help improve their environmental performance. This research explores how to stimulate and support sustainable behaviour within project scope in a marine contracting organization through designing a suitable intervention. This intervention combines the design principles discovered with theories from gamification. From creative thinking and exploring the different means of gamification in a sustainability context, gamification was chosen as a suitable format for the intervention. The objective of the intervention is to stimulate people to think of sustainable solutions in their work by making them aware of environmental impact and actions. More important, it is a fun and interactive introduction to highlight the contribution one has to the total environmental footprint of the company. The game is designed to be played by project teams that start with the project's conceptual design phase within a marine contractor organization. The game's purpose is to become aware of the environmental impact indicators and actions and to share individual values by deciding what investments to make in reducing the impact of the fictitious project. Players are challenged during the game to make strategic decisions to design their fictitious wind project that will have an as low as possible environmental impact. This is to make sustainability and environmental impact more tangible for the project team and ensure that employees can start discussions on sustainability within the marine contracting industry from a common ground and experience on sustainability.