PowerPointPrsentation

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Modelling Mud and Sand Transport in the
East-Frisian Wadden Sea
Modellierung von Sedimenttransporten im Wattenmeer
- Gerold Brink-Spalink -
Gerold Brink-Spalink Jörg-Olaf Wolff Emil
Stanev
Forschergruppe BioGeoChemie des Watts
BioGeoChemistry of Tidal Flats (SP 4)
TP 4
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• Overview
• Model Area East Frisian Wadden Sea
• Sediment Transport Model
• Model Results
• Conclusions

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Study Area Spiekeroog Island
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Model Area East Frisian Wadden Sea
7 Basins
Volume High Water 184 Mio m³
Spiekeroog Basin (spring tide)
Volume Low Water 39 Mio m³
Area 71 Mio m²
Inlet width 2500 m
Inlet area 11000 m²
Maximum channel depth 12 m
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• Overview
• Model Area East Frisian Wadden Sea
• Sediment Transport Model
• Model Results
• Conclusions

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Hydrodynamic Model (GETM)
Momentum equations
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Hydrodynamic Model

• 3D-model
• horizontal resolution 200 m
• vertical resolution D/10 (Dwater depth)
• vertical grid s-coordinates
• Time discretization mode splitting
• Dt13s for sea level, vert. integr.
  Velocities
• Dt215s for 3D-fields turbulent variables,
  ...)

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Sediment Transport Model
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Boundary conditions

• Sediment on ground (Sand 100µm, Mud) unlimited
• Morphologic changes during model run are not
  considered in topography data
• Water flowing into model area carries no sediment
• Sediment flowing out of model area is lost
• Sediment model is initialized half a tide after
  hydrodynamic model

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• Overview
• Model Area East Frisian Wadden Sea
• Sediment Transport Model
• Model Results
• Conclusions

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Hydrodynamic conditions for erosion
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Integrated suspended sediment concentration
flood
high water
ebb
low water
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Sediment movements after 3 tidal cycles
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Model estimate of sediment types
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Time evolution of vertical concentration profiles
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Vertical average of concentration
Transport through inlet
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• Overview
• Model Area East Frisian Wadden Sea
• Sediment Transport Model
• Model Results
• Conclusions

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Conclusions

• A 3D-model for sediment transport has been set
  up, that accounts for the main processes
  (erosion, settling, deposition, advection,
  turbulent mixing)
• Suspended sediment concentration patterns show
  consistent behaviour with observations
• Spatial distribution of sediment types matches
  observations in large areas
• Further calibration with measurements necessary
• Waves need to be taken into account

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