Type
PhD research
Duration
March 2021 - March 2025
Persons involved
PhD student: Stephen George Emmanuel
Dr.ir. B.W. Borsje (daily supervisor)
Prof. Dr. Daphne van der Wal (co-supervisor)
Prof. Dr. S.J.M.H. Hulscher (Promoter)
Funding of the project
NWO – programme Saltisolutions
Summary of the research
Estuarine regions worldwide are facing salt intrusion problems due to various anthropogenic activities and climate change like Sea level rise and changes in rainfall patterns. This leads to drought conditions and lower fresh water river discharges in estuaries which are mainly responsible for balancing this salt intrusion in estuaries. This research focuses on the quantification of the activities of ecosystem engineers like mussels, oysters and wetland plants that create, maintain and modify their habitats. While these ecosystem engineers are known to interact with their physical environment and design it, the magnitude of their interaction still remains unclear. Therefore this research focuses on quantification of the activities of these ecosystem engineers in a real world estuary and map their footprints on an estuarine scale. The methodology adopted is integrating Earth observation techniques and field observation within a 3D modelling approach to study the morphodynamics, hydrodynamics and salinity aspects of the Rhine-Meuse delta. Also, the computational time of this high fidelity 3D model will be reduced by using surrogate modelling approach by making it either a response surface surrogate or a lower fidelity surrogate model.
This ‘eco-morpho-hydrodynamic’ model will give insight into the ‘mechanism’ and the ‘magnitude’ of the interaction that these ecosystem engineers have with their physical environment and their role in designing it on an estuarine scale. Their role in salinity mitigation and feedback due to increased salinity will also be assessed with the help of modelling. The knowledge from this ‘eco-morpho-hydrodynamic’ model will help in building an idealized model that will help to understand the combined effect of oyster and mussel beds and wetland plants on salinity and morpho-hydrodynamics within an estuary, apart from how they affect the occurrences of each other.
This research is in line with the ‘Nature-Based solutions’ for salinity intrusion mitigation in estuaries. The ‘grey’ solution is being questioned in the scientific community in terms of their sustainability and adaptability to climate change. ‘Green’ solutions are now being explored since they dynamically interact with the changing environment and adapt themselves in the face of climate change and its impacts. Therefore, they are thought to be potential resilient solutions in the long term for coastal defense and salinity intrusion mitigation.
Keywords
Salt intrusion, Rhine-Meuse delta, Ecosystem engineers, Remote sensing, eco-morpho-hydrodynamics model, surrogate model.
More information
Stephen George Emmanuel
Room Horst W200
Tel. +31 53 489 1998
E-mail s.g.emmanuel@utwente.nl