Die Küste, 81 (2014), 369-392
369
Modelling Large Scale Sediment Transport in the
German Bight (North Sea)
Manfred Zeiler ; Peter Milbradt, Andreas Pliif and Jennifer Valerius
Summary
The main objective of the multidisciplinary research project “AufMod” (2009-2012) was
the development of model-based tools for analyzing long-term sediment transport and
morphodynamic (MD) processes in the German Bight. AufMod aimed at bringing to
gether marine geoscientists and coastal engineers to build up consistent bathymetric and
sedimentological databases and to compare different numerical models using the same
data input and model grid with respect to uncertainties in their results.
AufMod provides a suite of consistent annual bathymetries as well as initial sediment
parameters which can be used by numerical MD models for further analyses. Different
patchy datasets from bathymetric survey campaigns since 1948 have been compiled and
have undergone a sophisticated postprocessing procedure to overcome inconsistencies
arising from the use of different echosounding techniques, vessels, tidal correction and so
on. For the first time, data on grain size distribution have been composed for the entire
North Sea including the German Bight in order to analyze geomorphological processes
and to calculate sediment input parameters for morphodynamic modelling. By establish
ing a so-called “Functional Seabed-Model” consistent annual bathymetries and initial sed
iment distribution and composition (grain size distribution) have been made available
together with their spatial and temporal uncertainties.
The morphodynamic numerical model simulations cover a time span from 1996 to
2008. They are based on natural processes and take account of the whole variability of
tides, external surge, river run-off, wind and waves. “AufMod” provides a suite of con
sistent annual bathymetries as well as initial sediment parameters which can be used by
numerical MD models for further analyses. By using the same model grids the strength
and weakness of the different numeric models can be evaluated and their uncertainties
can be assessed. The morphodynamic model results provide a first comprehensive im
pression of die resulting sediment transport pathways in the German Bight.
Further model runs have focused on the sensitivity of sediment transport and the
morphological response due to wind forcing, mean sea level rise and variation in porosity.
Keywords
North Sea, German Bight, sediment mixture, sediment distribution, porosity, bathymetry,
sediment transport, morphodynamic, numerical modelling, mean sea level rise
Zusammenfassung
Der Aufbau von integrierten Modellsystemen (AufMod) g/ir Analyse der langfristigen Morphodynamik
in der Deutschen B/icht war Ziel des KF¥J-]Prbnndforschnngsvorhabens (Daifyeit: 2009-2012). Ahs-