Exchange of Young Researchers within the THESEUS project


Siddharth Narayan is a THESEUS-funded PhD student at the University of Southampton, under the supervision of Prof. Robert Nicholls and Dr. Derek Clarke. His PhD topic is "Development of A 2D Modelling Framework for Quantitative and Qualitative Risk Assessments of Coastal Floodplain Systems." As part of his PhD, Siddharth spent one month at KULeuven under the supervision of Prof. Patrick Willems and Prof. Jaak Monbaliu investigating the application and effectiveness of the 2D Source-Pathway-Receptor (SPR) model in the Dendermonde region of the Scheldt-Dender basin in Belgium.

He says: "I am extremely grateful to Prof Patrick Willems, Prof Jaak Monbaliu, Prof Robert Nicholls, Dr. Derek Clarke, and the THESEUS project for this unique opportunity to test and extend my PhD work in KU Leuven. I am very grateful to my research colleagues Duc Anh Nguyen, Vincent Wolfs, Qilong Bi and others at KU Leuven for their extensive help and cooperation during my stay there.

The aim of my work here was to use the 2D SPR model to capture and assess relationships between land-use and flood risk levels for the Dendermonde region of the Scheldt-Dender river basin using a systems approach. This work is an extension of previous collaboration with KU Leuven on applying the conceptual 2D SPR model for the Scheldt basin and the Dendermonde region. The conceptual model highlighted the advantages of the 2D SPR approach as a truly integrative and comprehensive method of studying complex floodplains. This is now being extended to a simplified quantitative modelling framework to assess dynamic changes to floodplain system characteristics. The main objectives of the work are as follows:

  • The first objective was obtaining integrated flood extent information for the Dendermonde region that recognised the combined influence of the both the Dender and Scheldt rivers. Since the two systems have hitherto been analysed separately, a simplified flood model was created in Mike 11 that integrated outputs from more detailed simulations of the two river systems for flood events of a range of extreme return periods (500 to 10,000 years) to produce an indicative flood map for the region;
  • The next stage of the work - currently ongoing - involves the extension of the qualitative 2D SPR approach to a quantitative rapid assessment framework. This framework comprises a static storage-based flood spreading model and a time-dependent systems model. The flood model is tested and validated against the simplified Mike 11 simulations and provides information on flood extent and depth, used to calculate floodplain flood risk. The systems model is used to simulate long-term changes to floodplain elements using existing knowledge and relationships from the qualitative 2D SPR;
  • The final objective is the assessment of the influence of land-use on flood risk levels for the floodplain by combining the qualitative and quantitative 2D SPR models.
Dendermonde SPR Map
Dendermonde SPR
Source-Pathway-Receptor (SPR) maps for the Dendermonde estuary

It is expected that the results from this work will provide a novel rapid, robust and scalable method for assessing the effects of land-use changes on floodplain flood risk levels. The work done at KU Leuven has also been very helpful towards achievement of my PhD objectives and will hopefully lead to further collaboration in the area in the near future."


By Siddharth Narayan