Presentation by Bart Grasmeijer (Arcadis) at the Delft3D User Days, during Delft Software Days 2016. Wednesday 2 November 2016, Delft.

1. TIDE-INTEGRATED SEDIMENT TRANSPORT IN
TIDAL CHANNELS AND EFFECT OF CHANNEL
DEEPENING
Effect of deepening the Rotterdam Waterway on turbidity
maximum
2 November 2016

2. © Arcadis 2016
Outline
 Study area
 Results Delft3D model
 Conclusions

3. © Arcadis 2016
Rotterdam Waterway
 Ship canal from Rotterdam to North Sea
 Artificial mouth of river Rhine
 Length of 20 km
 Width 480-675 m
 Depth 14.5-16 m below NAP
 Started in 1866 (150 years!), opened in 1872
 Stairway line (trapjeslijn) 1970
 Closing off Haringvliet 1970
 Flood protection system Maeslantkering (1997)
 Mean tidal range 1.7 m
 Discharge 500-4500 m3/s
 Sand D50 = 200-350 µm
 Mud 10-35%
Botlek
Hoek van Holland

4. © Arcadis 2016
Bed level
 Hoek van Holland NAP-16 m
 Botlek NAP-14.5 m

5. © Arcadis 2016
Dredging volumes in Rotterdam Waterway
 1970’s: ~2x106 m3 per year
 2010’s: ~0.5x106 m3 per year
 Change in dredging and disposal strategy
 Staircase line (trapjeslijn)
 Haringvliet closed off

6. © Arcadis 2016
Residual current
Hoek van Holland Botlek

7. © Arcadis 2016

8. © Arcadis 2016

9. © Arcadis 2016
Computed mud concentrations
Van Rijn (2007)
transport module
in Delft3D
(mud and sand)
Agrees with
measurements
50% discharge
1 mud fraction
1 sand fraction

10. © Arcadis 2016
Deepening

11. © Arcadis 2016
Peak flood velocities

12. © Arcadis 2016
Extra siltation

13. © Arcadis 2016
Effect on mud concentrations
However:
Import increases
slightly
Effect on long
term?

14. © Arcadis 2016
 Mud transport along Rotterdam Waterway is non-saturated transport over a mainly sandy bed
 Mud concentrations in ETM are supplied by the river and from sea
 Deepening increases salinity intrusion and causes larger peak flood velocities at seaward side of
deepened stretch
 Initially, deepening Nieuwe Waterweg around Botlek results in small landward shift of turbidity maximum but
not in increase of maximum
 Deepening results in larger sedimentation rates in harbour basins
 However, deepening also results in slightly more mud import
 Start MSc research: effects on bed composition and turbidity on long term (years)
Conclusions

15. © Arcadis 2016
Arcadis.
Improving quality of life.

16. © Arcadis 2016
Staircase line

17. © Arcadis 2016
Discharge as function of Rhine discharge
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
0 2000 4000 6000 8000 10000 12000 14000
Lokaleafvoer[m3/s]
Bovenrijnafvoer [m3/s]
Nieuwe Waterweg Nieuwe Maas Oude Maas

18. © Arcadis 2016
Suspended sediment concentrations
Source: De Nijs (2012)

19. © Arcadis 2016
Depth-averaged concentrations
Source: Snippen et al. (2005)