The surge in demand for inland vessel goods transportation has necessitated the operation of larger vessels with increased drafts. These larger vessels generate significant induced loads from their more powerful bow thrusters during berthing and mooring. These loads can lead to scour, which ultimately results in instability of the quay wall. To counteract this, stone gradings are penetrated with colloidal concrete as bottom protection. However, prior studies indicate that the flow velocity profile perpendicular to a quay wall decreases more rapidly than guidelines suggest, implying a potential reduction in the extent of colloidal concrete application. This is relevant for the Netherlands, where a multitude of hydraulic structures, including an estimated 130 locks, are in need of renovation or replacement. \\

\noindent This study seeks to comprehend the impact of bow thruster-induced loads directly perpendicular to the quay wall, on stone displacement near a quay wall and this study compares the outcomes of this field measurement with existing guidelines and scale modelling. The research question is therefore: ''\textit{How can results from a full-scale test improve the design and performance of loose-rock bottom protection against bow thruster-induced loads for quay walls accommodating inland vessels?}''\\

\noindent In order to answer this question a full-scale field measurement is conducted with the largest inland vessel in Europe. During this field measurement, free flow tests were performed and bottom velocity, pressure fluctuations and stone displacement were determined. \\

\noindent The applied bow thruster power and under keel clearance are marked as two important parameters for stone displacement. For the impact of this applied bow thruster power and under keel clearance, a variety of scenarios is examined. After each scenario a survey is done to look at individual stone displacement. Velocity measurements are taken to get more information about the flow velocities. The velocities were measured relatively far away from the bottom, resulting in low velocities. The actual bottom velocity is determined by validating and using the findings of the scale modelling performed by \textcites{Deltares}.\\

\noindent Free flow tests are performed to directly measure the outflow velocity and compare it with existing guidelines. From these tests, it is concluded that the existing guidelines for outflow velocity result in an overestimation of the required $d_{n50}$, with a measured loss coefficient of 0.65 as opposed to the proposed 0.90. Even with the reduced loss factor for the outflow velocity, the bottom velocity calculated with the Dutch method guideline is higher compared to the actual bottom velocities, demonstrating again, as already indicated in prior studies, that the guidelines are too conservative. \\

\noindent The turbulence intensity values play a significant role in validating the findings derived from scale modelling conducted by Deltares. The measured turbulent intensity values show similarities with the earlier findings, indicating a turbulent environment and validation of the Deltares scale modelling. \\

\noindent Based on pressure measurements, it is estimated that at the onset of movement, the pressure differences of the turbulent eddies are in the order of 50 to 90\% of the critical force to cause stone movement. \\

\noindent The in this study developed parameter R = $\frac{V_0}{UKC} \cdot t \cdot \frac{1}{k_{sl}} \cdot C_R $ shows that an increase in applied bow thruster power, a decrease in under keel clearance, an increase in duration and in slope lead to a linear relation with the normalised cross-section area of the near-quay erosion hole. \\

\noindent In addition, the full-scale field measurement showed that the stone displacement predominantly occurs within the first two and a half meters of the bottom protection, suggesting a possible reduction in the width of the colloidal concrete application. For a fictive quay wall the suggested reduction is compared with the design following the original guidelines. The suggested reduction alternative could save 75\% of the amount of colloidal concrete and CO$_2$ emissions.

Sint Eustatius is a Caribbean island located in the north of the Lesser Antilles. The coastline west of the capital, Oranjestad Bay, is of vital importance to the island as it is here where tourism, recreation, the harbour and historical ruins are located. On the other hand, Oranjestad Bay has a heavily fluctuating beach, which is undesirable. The Public Entity of St. Eustatius is investigating the possibility of a coastal solution that could preserve and extend this beach. However, there is insufficient knowledge of the hydrodynamic processes and morphology available to design a solution. By analysing the morphological system, this study aims to advise the Public Entity of St. Eustatius on the decision for a coastal solution to create a beach in Oranjestad Bay.

A literature study was performed to obtain basic knowledge of the coastal system of Oranjestad Bay. A two-dimensional numerical Delft3D model was then developed to gain more in-depth knowledge of the wave, current and sediment patterns. The result of both findings is combined in a conceptual model, where the cause of the beach fluctuations along Oranjestad Bay was analysed. Based on the system knowledge and stakeholders’ demands and regulations, three alternatives to create a beach at Oranjestad Bay are proposed. The alternatives are qualitatively verified and evaluated with a multi-criteria analysis and cost-value ratio.

The literature review shows that Oranjestad Bay has the characteristics of a wave-dominated coast. The seasonal wave climate has a strong influence on the beach fluctuations that occur in Oranjestad Bay. The influence of tides and wind on sediment dynamics is expected to be minimal. The modelling study concluded that the wave climate can be described by three main wave conditions, namely a sea condition, a storm condition and a swell condition. The different hydrodynamic and morphodynamic characteristics of these conditions provide a reasonable simulation of the coastal processes in Oranjestad Bay. The model results give an impression of the seasonal wave climate and a net northward sediment transport capacity is found. These results are consistent with the expected coastal morphodynamics found in the literature study. The effect of a storm is less well represented in the modelling study. This limitation is caused by the modelling approach. In addition, there are some uncertainties in the model due to the lack of detailed coastal data in the nearshore. The conceptual model indicates that the coast of Oranjestad Bay may experience seasonal gradients
in alongshore sediment transport leading to beach fluctuations. From April to September, beaches are likely to erode due to net northward sediment transport. In addition, beaches erode due to periodic storm conditions that occur from June to November. It has been found that the recovery of beaches after a storm varies along Oranjestad Bay. Scubaqua beach recovers much faster than the beach at Smoke Alley. This is due to the larger sediment transport capacity in the alongshore direction at Smoke Alley beach, the amount of larger cobbles on the shoreline of Smoke Alley and the lack of sediment north of Smoke Alley...

Ecosystems are under pressure worldwide, due to both natural and anthropogenic stresses. Stresses on ecosystems can cause a decline in biodiversity, a loss of habitat and a deterioration in ecosystem services. To avoid further pressure on ecosystems caused by advancing economic development, new infrastructure projects should be integrated into the ecosystem. Environmental Impact Assessments (EIAs) are now mandatory for projects that are likely to have significant environmental effects. EIAs have primarily focused on mitigating negative impacts. However, recently new design philosophies have emerged such as ‘Engineering with Nature’, ‘Working with Nature’ and ‘Building with Nature’ which also focus on promoting positive impacts.
Constructively realizing nature-inclusive projects is complicated due to involving stakeholders with dif-fering perspectives. Therefore, in an integrated approach towards new marine infrastructure devel-opment, the next step is to promote constructive collaboration between stakeholders to systematically investigate the nature-inclusive potential of infrastructure. This thesis describes a proposed strategy for doing so, within the context of nearshore infrastructure development located in or nearby coral ecosys¬tems. The focus is on how nature-inclusive potential of new marine infrastructure might be maximised, taking into account the local ecosystem.
The aim of this research is to find an optimal approach to develop coral-inclusive infrastructure. This is done by structuring the required discussions between stakeholders considering socio-economic, ecolo¬gical and engineering perspectives regarding the nature-inclusive design potential of new marine infra¬structure. For this purpose, a method was developed that proposes a step-by-step strategy to promote constructive collaboration between relevant stakeholders, consisting of the following five steps:

1. project description, outlining the basic challenge at hand

2. project location analysis, involving a systematic assessment of the relevant ’natural system’ as well as the ’anthropogenic system’

3. Development of marine infrastructure design applications, involving an inventory of project ele­ments that can have negative or positive effects on the overall ecosystem

4. inventory and ranking of potential measures, objectively outlining feasibility and potential effect­iveness of measures and design modifications

5. summary of sustainable design recommendations, leading to a systematic ranking of potential measures proposed to support further decision making.

We have investigated the effectiveness of the systematic method, by applying it to a case study in Sint Eustatius that investigates whether the intended extension of a breakwater in Sint Eustatius can be designed as a coral-inclusive project. Sint Eustatius was chosen because Rijkswaterstaat offered research opportunities on location. In an ideal case, the use of long-term consistent data maps the nat¬ural factors over a longer period of time. This provides greater certainty of results and recommended actions. However, the values that were reported for the Sint Eustatius case were not derived from long term systematic data collection. Furthermore, the substrate from the existing breakwater looks to be promising for coral recruitment. However, there is not a lot of coral development evident on the existing breakwater. Possible negative factors hindering coral development on the existing breakwater are: 1) poor water quality; 2) high hydrodynamic circumstances with high wave action in shallow waters which limits the type of coral species; 3) inconsistent larval supply through ocean currents.
Coral reef connectivity seems sufficient and potential substrate is already present in the existing break¬water. Extension of the breakwater will lead to substrate increase which could improve the chance for coral recruitment in a hurricane-risk area as Sint Eustatius. A valid next step that could be proposed to aid a better understanding of this habitat is to invest in an extensive and dedicated data gathering campaign.

In conclusion, the main improvements derived from the application of the systematic approach for nature-inclusive potential for infrastructure projects are:

·  providing an overview of the steps required to create coral-inclusive infrastructure,

·  instigating the investigation of the status or the possibilities for coral development,

·  assisting ecologists and engineers to structure the discussion on coral-inclusiveness,

·  lowering the barrier to use (new) design philosophies,

·  and stimulating coral development and decreasing negative effects by providing design recom­mendations.

Bringing stakeholders with different perspectives together in one nature-inclusive project plan remains challenging. Environmental data can play a role in arriving at a realistic approach supported by ecolo­gists and civil engineers to realize nature-inclusivity for infrastructure. This requires knowledge, money and time and could provide insight into the threats and opportunities. The systematic approach, derived in this thesis, has been proven to support stakeholders in assessing the nature-inclusive potential of marine infrastructure.