Coastal dunes play a crucial role in protecting sandy coastlines while supporting valuable ecological functions. Their development reflects interactions between wind-driven sediment transport, marine hydrodynamics, and vegetation. In particular, early-stage dune vegetation of marram grass, strongly influences whether bare sand surfaces evolve into patchy embryonic dunes and, ultimately, continuous foredune ridges. Despite its importance, vegetation is often represented in coastal models in a highly simplified or prescribed manner, limiting the ability to reproduce the spatially heterogeneous and stochastic nature of early dune development observed in reality.

This thesis investigates how the dominant environmental drivers of embryonic dune vegetation can be translated into a reduced-complexity modelling framework that reproduces observed development tendencies at coastal-system scales. The focus is behavioural realism rather than detailed plant physiology, capturing when and where vegetation establishes, persists, densifies, or is destroyed as a result of interactions between physical forcing and feedbacks.

A probabilistic vegetation model is developed in which patterns emerge from the balance between establishment and decay. Three controls govern this balance: limitation by water-level exposure, morphodynamic suitability based on burial and erosion, and spreading from existing vegetation. These controls jointly determine establishment and survival probabilities, allowing vegetation to arise dynamically rather than being imposed. The model is implemented in a one-way forced configuration using spatial bed-level change fields and a representative marine water-level signal extracted from an existing coupled marine–aeolian morphodynamic simulation. Hence, vegetation, responds to, but does not modify, the hydrodynamic, aeolian, or morphodynamic forcing.

The model is applied to the Sand Engine mega-nourishment in the Netherlands, which provides a unique natural laboratory due to its unprecedented scale, initially bare sandy surface, rapid morphological evolution, and extensive research and monitoring record. Model results are evaluated at multiple levels, including domain-scale development trends, sub-area specific indicators derived from observations both in time and space, and process-based diagnostics using selected points of interest. This multi-level evaluation allows assessment of both emergent vegetation patterns and the underlying mechanisms driving them.

The results indicate that the model is able to reproduce several characteristics of embryonic dune vegetation development observed at the Sand Engine. Vegetation expansion occurs within realistic spatial and temporal scales, exhibits asymptotic mean densification behaviour, and responds coherently to geographical steering by features such as the dune lake. The analysis highlights the importance of stochastic establishment, facilitation through nearby vegetation, and spatially variable bed-level change in generating realistic heterogeneity. Limitations include sensitivity to water-level thresholds in flat nearshore areas, overestimation of vegetation merging rates in some locations, and constraints imposed by spatial resolution and one-way forcing.

These findings demonstrate that simplified behavioural representations can capture essential dune–vegetation dynamics when dominant environmental controls and stochasticity are included explicitly. The framework is suited for exploratory and comparative studies of dune development and for scenario-based assessments in coastal management. Recommendations are made for future integration of the vegetation model into fully coupled marine-aeolian models, where vegetation feedbacks on sediment transport and dune initiation can be explicitly represented, enabling more comprehensive simulation of dune–vegetation co-evolution. ... Read more

The erosion problem along Playá Union presents significant challenges for future port expansion at Puerto Rawson. This research seeks to address the question of how to achieve a sustainable and durable port expansion, while minimizing environmental impacts, particularly concerning sediment imbalance along the coastline? Using 30 years of wave data, both normal and extreme wave conditions are simulated with SWAN, a numerical based wave model. Conceptual port expansion designs are developed, resulting in a final design with an integrated fully dimensioned breakwater. Based on visual inspections, data, and research, a new cement mixture is proposed for the breakwater armour units. A Life Cycle Assessment evaluates the environmental impact, while the effect on alongshore sediment transport is assessed using the SWAN model outcomes and the CERC formula. Visual inspection of the current breakwaters lead to a 6.3% reduction in material use in the new breakwater through reuse of armour units. Furthermore, the proposed cement mixture integrates porphyry quarry waste as the coarse aggregate, a choice also supported by prior research in sustainability. With the new End-of-Life approaches added, the total shadow costs are reduced by 22%. The hydrodynamical analysis and model result in extreme wave heights up to 3.98 m at the toe of the breakwater. By applying a neural network and a k-means algorithm on the wave data, five regular wave conditions are run in the SWAN model. The alongshore sediment transport is impacted by new breakwater concepts. Relying solely on the breakwater layout to counteract erosion north of the port, however, does not prove to be a viable approach. Based on design criteria and aspirations, the final conceptual design proposes the removal of the existing southern breakwater, while retaining sufficient space for future port expansion. The breakwater, integrated in the final design, is dimensioned based on standard design principles. To conclude, the data and model provide valuable insights into the coastal dynamics around Puerto Rawson. The proposed concrete mixture, along with the End-of-Life solutions, minimize environmental impact and enhance durability of the armour units. The sustainable breakwater design, effectively integrated into Puerto Rawson, accommodates for future port expansions ... Read more