The Noordstrand of the Marker Wadden has been subject to much more erosion than expected. From our current understanding of this low-energy system we cannot explain what has been the cause of this. The goal of this thesis is to create a better understanding of the different processes responsible for the development of this non-equilibrium beach in a low-energy lake environment. A better understanding of the link between hydrodynamic and morphodynamic processes can be used for the maintenance of the existing Marker Wadden beaches and the design of new sandy protections in this kind of systems. By combining the results of a hydrodynamic and morphodynamic data analysis with the results of the Delft3D Marker Wadden model, it is possible to create a conceptual system description. This can be used to improve our understanding of the Noordstrand development and the responsible processes. In this system description the influence of the general Markermeer system cannot be neglected as the different systems (Markermeer, Marker Wadden and Noordstrand) cannot be regarded separately as the different hydrodynamic processes are linked.

In Chile, the Biobío river separates the cities of Concepción and San Pedro de la Paz. Bridges crossing the Biobío river ensure a fast and dependable connection, which contributes to the transport options in the region. With the Biobío region being the second largest contributor to the country's GDP, an unreliable transport network is highly undesirable. However, this is exactly what happened since 2016. Some of the bridges crossing the river collapsed, excessive local pier scour near the foundation and negative effects of morphological dynamics were deemed to be one of the causes. Furthermore, Chile is prone to earthquakes and the resulting tsunamis, which can also damage the structural integrity of the bridge. The Chilean Railroad Agency (EFE) wants to realise a new railroad bridge crossing the Biobío river in Concepción, replacing the existing century old railway bridge. To prevent the failure of the new railway bridge, which can result in unnecessary economic damages, the morphological influence and damages due to scour, earthquakes and tsunamis, must be thoroughly understood and modelled. This process of modelling the current and future situations of the Biobío river is part of this project, using Delft3D-FLOW and NeoWave as modelling agents. With the outcomes the programme of requirements and the preliminary design for the bridge are updated and presented.