A comparison between two very different numerical models is presented: Delft3D and XBeach. Delft3D (Deltares) calculates non-steady flow and transport phenomena that result from tidal and meteorological forcing. The wave propagation is calculated in the frequency domain. XBeach (Unesco-IHE, Delft University and Deltares) consists of formulations for short wave envelope propagation (time-dependent wave action balance), non-stationary shallow water equations, sediment transport and bed update. The model is able to resolve the time dependent long waves, which are important in the surf zone. A number of simplified cases are defined beforehand taking into account actual features and conditions existing in chosen problem areas. The examination of these simplified cases allows for the identification of driving processes and the assessment of the sensitivity to certain relevant parameters, with the advantage of working in scenarios of limited complexity and without excessive computational load.@en

This paper demonstrates that the Belgian Continental Shelf and coastal plain occupy a key position between the depositional North Sea Basin and the erosional area of the Dover Strait as it is an area where erosional landforms and fragmented sedimentary sequences provide new evidence on northwest European landscape evolution. The study area hosts 20-30m thick penultimate to last glacial sand-dominated sequences that are preserved within the buried palaeo-Scheldt Valley. Here, we build on the results of previous seismo- and lithostratigraphical studies, and present new evidence from biostratigraphical analysis, OSL dating and depth-converted structure maps, together revealing a complex history of deposition and landscape evolution controlled by climate change, sea-level fluctuations and glacio-isostasy. This study presents strong new supportive evidence on the development of the incised palaeo-Scheldt Valley landform that became established towards the end of the penultimate glacial period (MIS 6; Saalian) as a result of glacio-isostatic forebulge updoming, proglacial lake drainage and subsequent collapse of a forebulge between East Anglia and Belgium following ice-sheet growth, disintegration and retreat in areas to the north. The majority of the incised-valley fill is of estuarine to shallow marine depositional context deposited during the transgression and high-stand of the last interglacial (MIS 5e: Eemian). A thin upper part of the valley fill consists of last glacial (MIS 5d-2: Weichselian) fluvial sediments that show a gradual decrease and retreat of fluvial activity to inland, upstream reaches of the valley system until finally the valley ceases to exist as the combined result of climate-driven aeolian activity and possibly also glacio-isostatic adjustment. Thus, strong contrasts exist between the palaeo-Scheldt Valley and estuary systems of the penultimate glacial maximum to Last Interglacial (Saalian, Eemian), the beginning of the Last Glacial (Weichselian Early Glacial and Early-Middle Pleniglacial), and the Last Glacial Maximum to Holocene.@en