Title: Effect of Different Sediment Mixtures on the Longterm morphological Modeling of Tidal Basins
1Effect of Different Sediment Mixtures on the
Long-term morphological Modeling of Tidal Basins
NCK Days 2009 Texel
- Ali Dastgheib, Dano Roelvink, Mick van der Wegen
2Introduction (why?)
- Recently the process-based morphological models
are used more often in mid-term (decades) or
long-term (centuries) - Very long-term Simulations, West Eschelt (Mick
van der Wegen) - Texel inlet (Edwin Elias)
- Marsdeip (Ali Dastgheib)
- Willapa Bay (G. Lesser)
- One of the main shortcomings of the results are
unrealistic narrow and deep channels.
3Morphological model mid/long-term
Morpholgical Tide Wave condition
Hydro- dynamics
Sediment Transport Relations Slope
effect Avalanche effect
RAM Correction factor Online
Morphological changes
Sediment / Transport
- In most of the mid/long-term morphological
simulation the sediment is schematized with one
D50 over all the model
4Research objectives
- In this research our focus is on the use of
different sediment fractions in order to model
some of the neglected processes and show their
effects on the long-term simulation of tidal
basins (Wadden Sea is selected as the case study) - Further more we want to suggest a procedure to
use the result of this research in practice
5Available Data
- Soil Sampling in the Dutch Wadden Sea
- 1989 1997
- Malvern laiser particle sizer
- summerized in SedimentAtlas of Wadden Sea
6(No Transcript)
7Available Data
8Available Data
9Sediment Size Schematization
10Sediment Size Schematization
- 6 Sediment Fractions based on the sieve test
- Min of 75µm to max of 2.36 mm
- Min diameter, Max diameter (425 600 µm)
- loguniform distribution
- No cohesive Sediment
- No Mud
11Sediment Size Schematization
12Case Wadden Sea
M-Direction70 N-Direction127 Nr of Grid
Cells6876
Vl
Ei
Ma
13Model Setup
- Forcing
- M2,M4,M6
- O1,K1 (C1)
- Bed Slope Effect
- Dry Cell Erosion
- Mor. Fac 300
- Mor.Time 500 yrs
- 5 Simulations
D - 4.54
14Hypsometry
15(No Transcript)
16(No Transcript)
17(No Transcript)
18What is the use of it?
- Maybe we can have an intelligent guess for the
initial condition in real case morphological
simulations. - Relate the d50 Variance of Velocity
- Hydrodynamic simulations for 5 tidal cycles using
the resulting bathymetries
19(No Transcript)
20Real Case Wadden Sea 1930
M-Direction140 N-Direction254 Nr of Grid
Cells6876
Vl
Ei
Ma
21Available Bathymetry data
- 1926 2007
- UCIT Data
- MATALB Routine, Make a bathymetry for desired
year - Linear interpolation between available data
- If the target year is earlier than the first
observation or later the last one within the 5
years different, the available data was used - Projected on the Computational mesh
-
22Model Setup
- Forcing
- M2,M4,M6
- Bed Slope Effect
- Dry Cell Erosion
- Mor. Fac 75
- Mor. Time 75 yrs
- Initial bathymetry
- 1930
- One Fraction with spatially varying d50
231930-2000
2000 Var. d50
2000 One d50
2000
1930
241930-2000
25(No Transcript)
26Next Steps
- Add finer sand to the fractions
- Compare the Basin Characteristics
- Compare the Skill Score of the Models
- Run 1930-2000 simulations with number of sediment
fractions