This thesis introduces a new algorithm for optimising shipping routes within a dredging project. Highly dynamic and time-dependent hydrodynamic features influence shipping routes. Due to the complex interactions between the horizontal tide, vertical tide, stratifying forces, wind-driven forces, and limited water-depth, shipping routes were previously only optimised for large scale routes (order of 1000 km). This study presents an algorithm that can optimise shipping routes that are influenced by these small scales (order of 10 km) hydrodynamic features. This algorithm uses graph theory to solve for the time-dependent fastest path between start and destination. Graph theory searches for the optimal path through a set of nodes that are connected with edges. This study uses the time-dependent shortest path algorithm which accounts for the FIFO-criteria (Waiting criteria) and can solve the non-convex nature of the problem The input of this algorithm is a hydrodynamic model. These models are Computational Fluid Dynamic (CFD) models that calculate currents and water levels in a specific domain. The domain is discretised into cells and nodes to calculate these hydrodynamic features. This study uses the nodes of this hydrodynamic model as the vertices of the graph. However, for some cases, the hydrodynamic model has too many nodes for the shortest path algorithm. This study presents a method for reducing the number of nodes without reducing the spatial resolution. The nodes are reduced based on a combination of the vorticity and the magnitude of the flow. This algorithm is implemented in a python software package named Hydrodynamic Algorithm for Logistic enhancement Module (HALEM). HALEM can determine the optimal shipping route for a given hydrodynamic model. Defining different cost functions results in different optimisation purposes. This thesis presents cost functions for the fastest route, shortest route, cheapest route and least polluting route. This software is then implemented in the OpenCLSim software so that this combination of software can optimise routes of entire projects. A case study simulates a beach-nourishment at Schouwen Westkop Noord to demonstrate the practical use of HALEM and OpenCLSim. For this project, 425,500 m3 sand should be dredged offshore and pumped onto the beach. Due to the narrow gullies and tidal changes in hydrodynamic features, the routes were hard to predict. The simulation with HALEM and OpenCLSim shows an increase in the production with 21 % compared to the simulation with just OpenCLSim.

To combat the emission of greenhouse gasses and the corresponding climate change, emission reduction goals have been established in the recent Paris Agreement. In order to meet these reduction goals and minimise the global average temperature increase, implementation of renewable energy sources is critical. Wind energy is one of the fastest growing renewable energy sources in the European Union, since Europe has the largest offshore wind energy capacity with its shallow shelf sea: the North Sea. Over the last twenty years, the wind energy capacity has increased significantly to become the current second highest power generation form of the European Union. The downside to offshore wind energy however, are the high costs that come with its generation. Cable losses of alternating currents between the wind turbines and the shore become increasingly high, as the distances towards the shore increment. For long distances, this inefficiency becomes unacceptable and conversion to a direct current is deemed necessary. A recently presented concept that aims to reduce the costs of offshore wind energy, is the concept of a large scale roll-out of interlinked offshore turbines, coordinated at an European level, including a so-called hub island. This artificial island facilitates converters, as well as a home base for engineers and large scale power storage. Technically, no big problems are expected with the construction of such artificial island. The major reason that could stop the hub island concept, is resistance from environmental organisations. To predict ecological repercussions of an artificial island, the impact on hydrodynamic parameters most important to the bottom of the marine food chain are explored. The primary producers represent this foundation of the food chain, and are most affected by the island through changes in water stratification and residual currents. These parameters highly influence the light and nutrient availability, thereby regulating the primary production dynamics of the ecosystem. By developing and applying the Three Dimensional Dutch Continental Shelf Flexible Mesh (3D DCSM-FM) model, the impact of an artificial island on the stratification and residual currents is explored for five case studies. Each case study comprises a 6km$^2$ cylindrical island, for different North Sea locations with distinct hydrodynamic properties. The implementation of an artificial island alters residual currents up to 10km from its position. The location determines the impact pattern, but influences remain local without any large scale North Sea impacts. Since changes in nutrient availability are only expected for large scale residual current impacts, no significant alterations in primary production dynamics are to be expected. The impact on stratification however, can have a significant influence on the dynamics of primary production. The originally well-mixed areas remain mostly unchanged, while islands in the more stratified regions can cause significant changes in absolute stratification up to 20km from the banks, and alterations in regimes or the seasonal onset timing up to 2.5km. The location and its hydrodynamic properties are paramount to the type of expected stratification impact, and proves to be an important design parameter for ecology around an offshore energy hub island in the North Sea.