Employment record

15-10-2015 PhD-candidate, University of Twente, Department of Water Engineering & Management, Uncertainty in long term bio-geomorphological dynamics for vegetated foreshores.


2013 – 2015 MSc Water Engineering & Management, University of Twente. MSc thesis: Sensitivity of sediment trapping capacity of estuarine mangrove forests, at National University of Singapore and University of Twente.

2012-2013 Minor Geo Data and Spatial Information, Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente.

2010-2013 BSc Civil Engineering & Management, University of Twente. BSc Thesis: Morphological changes of the Amelander Zeegat, at Deltares


Teaching experience

  • University of Twente: 2015-2016 Seminar morphology (supervisor)


  • Earth and Planetary Sciences

    • Salt Marsh
    • Marshland
    • Bed
    • Wave
    • Vegetation
    • Sea Level Rise
    • Investigation
    • Estuary


Current research

Uncertainty in long-term bio-geomorphological dynamics for vegetated foreshores. Vegetated foreshores live, i.e. their formation is controlled by vegetation dynamics and physical forces which significantly interact on a dynamic scale. This interdisciplinary field is labelled bio-geomorphology. Insight in the physical mechanisms behind landscape formation by bio-geomorphological interactions has substantially grown in the last decade. Nevertheless, the uncertainty in long-term (order of decades) dynamics of vegetated foreshores is not known so that reliable estimates of the contribution to safety of vegetated foreshores are impossible. Moreover, the opportunities to actively influence the long-term morphological development of vegetated foreshores via maintenance (e.g. grazing and cutting) are unknown, hampering application. In this sub-project of the BE SAFE programme (Building with Nature; BwN) we aim to quantify the uncertainty in morphological development for vegetated foreshores in a probabilistic way. We do this by explicitly accounting for the impact of four contrasting types of vegetation on both hydrodynamics and sediment dynamics. To set up the model we combine flume studies and field experiments executed in close collaboration with other sub-projects within the programme.


Biophysical Modeling of Mangrove Seedling Establishment and Survival Across an Elevation Gradient With Forest ZonesJournal of geophysical research: Earth surface, 129(5), Article e2024JF007664. Gijsman, R., Horstman, E. M., Swales, A., Balke, T., Willemsen, P. W. J. M., van der Wal, D. & Wijnberg, K. M.https://doi.org/10.1029/2024JF007664The impact of morphological evolution on hydrodynamics and sediment redistribution of the Western Scheldt estuary from 1200-2020In NCK DaysDays 2024 ‘Innovative science for a resilient coast’, March 13-15, IHE Delft: Book of Abstracts. IHE. Mi, J., Gerkema, T., Willemsen, P. W. J. M., van der Molen, J., van de Koppel, J., van der Wegen, M. & Bouma, T. J.https://www.nck-web.org/boa-2024/826-the-impact-of-morphological-evolution-on-hydrodynamics-and-sediment-redistribution-of-the-western-scheldt-estuary-from-1200-2020De kracht van kweldergras: Test DeltagootCiviele techniek, 78(1/2), 36-39. Willemsen, P. W. J. M., Klein Breteler, M., Antonini, A., Dermentzoglou, D., Muller, J. R. M., Mason, V., Bouma, T. J., Vouziouris, A., Buring, P., Bijvoet, D., Hofland, B. & Borsje, B. W.https://issuu.com/sjpuitgevers/docs/ct20241online?fr=sZTIzZDY1ODI0NTM
Morphological Response of a Highly Engineered Estuary to Altering Channel Depth and Restoring WetlandsJournal of marine science and engineering, 11(11), Article 2150. Siemes, R. W. A., Duong, T. M., Willemsen, P. W. J. M., Borsje, B. W. & Hulscher, S. J. M. H.https://doi.org/10.3390/jmse11112150Protective structures as adaptive management strategy in Nature-based Solutions to mitigate sea level rise effectsEcological engineering, 196, Article 107079. Siegersma, T. R., Willemsen, P. W. J. M., Horstman, E. M., Hu, Z. & Borsje, B. W.https://doi.org/10.1016/j.ecoleng.2023.107079Gradual versus episodic lateral saltmarsh cliff erosion: Evidence from Terrestrial Laser Scans (TLS) and Surface Elevation Dynamics (SED) sensorsGeomorphology, 426, Article 108590. van der Wal, D., van Dalen, J., Willemsen, P. W. J. M., Borsje, B. W. & Bouma, T. J.https://doi.org/10.1016/j.geomorph.2023.108590A comparison and coupling of two novel sensors for intertidal bed‐level dynamics observationLimnology and Oceanography: Methods, 21(4), 209-219. Xu, T., Hu, Z., Gong, W., Willemsen, P. W. J. M., Borsje, B. W., Van hespen, R. & Bouma, T. J.https://doi.org/10.1002/lom3.10540Exploring the Evolution of Salt Marshes: Investigating the Parametrization of Biogeomorphological Processes across Time Scales with Numerical Modelling. Dzimballa, S., Willemsen, P. W. J. M., Kitsikoudis, V., Borsje, B. W. & Augustijn, D. C. M.https://agu.confex.com/agu/fm23/meetingapp.cgi/Paper/1262745

Other contributions

Peer-reviewed journal papers

  • Willemsen, P.W.J.M., Horstman, E.M., Borsje, B.W., Fries, D.A., Dohmen-Janssen, C.M., 2016. Sensitivity of the sediment trapping capacity of an estuarine mangrove forest. Geomorphology, 273, pp 189-201. DOI: http://dx.doi.org/10.1016/j.geomorph.2016.07.038
  • Willemsen, P.W.J.M., Hulscher, S.J.M.H., Vermaas, T., 2015. Methods for analysing morphodynamics of tidal inlets. SURE! 1, pp. 1-4.

Conference proceedings

  • Willemsen, P.W.J.M., Borsje, B.W., Vuik, V., Janssen, S.K.H., Bouma, T.J., Hulscher, S.J.M.H., 2016. Long-term biogeomorphological behavior of coupled bare intertidal flats and vegetated foreshores. NCK-days 2016, Ouddorp, The Netherlands.
  • Willemsen, P.W.J.M., Vermaas, T., Hulscher, S.J.M.H., 2014. Morphological development of the Ameland inlet/Boschplaat in the Dutch Wadden Sea. NCK-Days 2014, Delft, The Netherlands, pp. 78.
  • Willemsen, P.W.J.M., Vermaas, T., Hulscher, S.J.M.H., 2014. Morphological development of the Ameland inlet/Boschplaat in the Dutch Wadden Sea. NCK-Days 2014, Delft, The Netherlands, pp. 78.


  •  MSc thesis Sensitivity of sediment trapping capacity of estuarine mangrove forests (still confidential).
  • BSc thesis Morfologische veranderingen Amelander Zeegat: een methodische aanpak, Morphological changes of the Amelander Zeegat (in Dutch).

Research profiles

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