Publications Dam Engineering

Journal publications


Modeling centuries of estuarine morphodynamics in the Western Scheldt estuary (Geophysical Research Letters)

ABSTRACT We hindcast a 110 year period (1860-1970) of morphodynamic behavior of the Western Scheldt estuary by means of a 2-D, high-resolution, process-based model and compare results to a historically unique bathymetric data set. Initially, the model skill decreases for a few decades. Against common perception, the model skill increases after that to become excellent after 110 years. We attribute this to the self-organization of the morphological system which is reproduced correctly by the numerical model. On time scales exceeding decades, the interaction between the major tidal forcing and the confinement of the estuary overrules other uncertainties. Both measured and modeled bathymetries reflect a trend of decreasing energy dissipation, less morphodynamic activity, and thus a more stable morphology over time, albeit that the estuarine adaptation time is long (approximately centuries). Process-based models applied in confined environments and under constant forcing conditions may perform well especially on long (greater than decades) time scales.

link: Geophysical Research Letters


Using a sand-mud model to hindcast the morphology near Waarde, the Netherlands (Maritime Engineering)

ABSTRACT Due to the construction of two cross-shore groynes near Waarde in the Western Scheldt estuary morphological changes in the area have occurred. A mud flat has developed between the groynes and at the tip of the groynes scour has occurred that has contributed to channel migration. Both the sand and mud fraction have contributed to this change. In this paper a process-based morphological model is presented that can reproduce most morphological changes thanks to the fact that both fractions are taken into account, as well as the interaction between sand and mud. Using the model five years of morphological changes were simulated from the construction of the groynes onwards. The Brier-skill score of the erosion/sedimentation pattern is 0.35, which means that the model has significant skill and can be classified as reasonable. A regression coefficient of 0.66 is found for the observed and modelled mud content in the bed after 5 years, which means that the model can reproduce the mud content reasonably well for most locations. The model can clearly distinguish between a sand or mud dominated area.

link: Maritime Engineering


Conference proceedings


Long-term modeling of the impact of dredging strategies on morpho- and hydrodynamic developments in the Western Scheldt

ABSTRACT The natural morphological developments of the Western Scheldt and the impact of human activities on these developments are investigated using a process-based morphological model called FINEL2d. The historical period of 1965-2002 is simulated in a T0 scenario including all the human activities that have taken place in that period. Besides this T0 scenario two extreme scenarios are modeled for the same period. The T1 scenario is carried out without any human activities from 1965 onwards. In the T2 scenario regular dredging of the navigational channel takes place, but the dredged material is not distributed back into the Western Scheldt like in the T0 scenario. In this way insight is obtained into how human activities have influenced and will influence the tide in and the morphology of the Western Scheldt. By modeling these different sediment strategies it is concluded that the applied strategy has had a large impact on the morphology of the estuary and tide during this period. The channels have deepened and the tidal flats have increased in the 1965-2002 in the model, because of which the hypsometry of the Western Scheldt has probably has become steeper over the last decades. The results also show significant effects on the propagation of the tide in the estuary. Due to the actual human activities over the past decades the tidal range in the estuary has increased by about 0.4m in Antwerp and accelerated the propagation of the tide with approximately 20 minutes. This corresponds to the observed phase shift in Antwerp over the past decades. The extreme scenario in which all dredged material was removed from the estuary shows that the process of increasing tide levels in the estuary may continue in case that the human activities are intensified.


Long-term performance of process-based models in estuaries

ABSTRACT This paper presents a 110 year morphodynamic hindcast for the Western Scheldt using a process-based model. The time period of 1860-1970 is simulated starting with the 1860 bathymetry. It is shown that the model can reproduce most major morphological changes in the estuary. A Brier-skill score of 0.48 is obtained at the end of the simulation, which means that the model has significant skill. Despite general concerns on the value of process-based models reproducing long-term morphological changes, it is concluded that this model captures important long-term morphological changes in the Western Scheldt.


Band width analysis morphological predictions Haringvliet Estuary

ABSTRACT Process based morphological models are used as a policy tool to predict the morphological changes due to (human) impacts. Due to computational time of these models sensitivity of the model results are often not considered. This paper presents a case study in the Haringvliet Estuary (the Netherlands) and shows that bandwidth in morphological predictions cannot be neglected. The questions to be answered in es-tuarine morphology should not only concentrate on the bathymetry after a period of (say) 10 years, but also on the accuracy ranges of the prediction.


High resolution long term morphological model of the northern part of the Holland Coast and Texel Inlet

ABSTRACT A high resolution morphological model of the northern part of the Holland Coast and Texel inlet is presented in this paper. The model includes the morphological effects of the combined action of tides and waves and focuses on the long term morphology (decades) that is dominated by the longshore coastal processes. This model has been set up and calibrated on observed morphological developments, and then applied to future development schemes. It was concluded that the model produces reliable results, making it a useful tool for decision making processes.


Long term process-based morphological model of the Western Scheldt Estuary

ABSTRACT A process-based morphological model of the Western Scheldt Estuary based on the finite elements method is presented in this paper. This model is able to successfully hindcast the morphological developments of the Western Scheldt over several decades. The measured sedimentation/erosion pattern versus the pattern calculated by FINEL2d over the period 1965 - 2002 was compared. Good agreement was found in overall patterns, although many differences were still to be seen in detail. It was concluded that the model can be used to evaluate different scenarios, making it a useful tool for decision making processes e.g. future deepenings of the fairway.