EurOCEAN 2000 - Vlaams Instituut voor de Zee

SEDIMENT TRANSPORT MODELLING IN MARINE COASTASL
CONDITIONS
INTRODUCTION
Leo C. van Rijn 1
1 Delft Hydraulics, P.O. Box 177, 2600 MH, Delft, The Netherlands
The state of the marine environment is a matter of concern for several countries within the
European Union. An important aspect of this is the future evolution of the coastline, where
uncertainty arises both from the morphological impacts of human interference (e.g. beach
nourishment and coastal protection schemes), and also the expected future rise in sea-level and
associated climatic variations. These changes may gradually alter patterns of waves and currents
and, hence, the sediment transport pathways in coastal areas. In the medium- and long-term, such
changes may profoundly influence the stability of the shoreline itself, with all that this entails for
the security and livelihoods of the large proportion of the population living near the coast.
The practical solution of real-life, coastal engineering problems in the short- and medium-term
necessarily involves site-specific studies, often including the acquisition of field data. However,
great expense is involved in carrying out field studies and, in recent years, increasing emphasis
has been placed on the development of computer-based, coastal sediment transport and
morphological modelling systems. Such models are generally capable of representing the surface
waves and currents in a coastal area with considerable accuracy. However, the same claim cannot
be made for their prediction of net sediment transport rates, due largely to our presently
incomplete understanding of detailed transport processes.
OBJECTIVES
The general objective of the present project sedmoc (sedmoc = sediment transport modelling in
marine coastal environments) is to fill gaps in our existing knowledge of transport processes of
non-cohesive sediments in the marine coastal environment.
The objectives of the project are summarized, as:
• To increase knowledge of the physical processes involved in transport of non-cohesive
sediment (sand) under the influence of waves and currents;
• To develop improved predictive mathematical models for the quantitative description of
sediment transport processes, which achieve accuracy within a factor of ±2 throughout the
physical parameter ranges of importance in coastal engineering practice and
• To deliver simplified sand transport models for use in coastal morphological models and in
coastal engineering practice.
To this end, detailed physical process models of differing complexity are being improved,
intercompared and validated in relation to experimental data from the laboratory and the field;
new laboratory experiments are being performed to investigate physical parameter ranges in
which uncertainty presently exists; and existing field data are being analysed to ensure that the
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