Presentation by Govert Verhoeven (Deltares) at the Delft3D - User Days (Day 1: Hydrology and hydrodynamics), during Delft Software Days - Edition 2018. Monday, 12 November 2018, Delft.

1. Delft Software Days - Edition 2018
Flood modeling in rural areas due to
extreme precipitation or levee breaches
Towards an integrated approach using Delft3D FM
Govert Verhoeven, Deltares

2. Recent Floods due to extreme rainfall
29 november 2018

3. Rainstorm in Delft
Deltares Delft, Thursday 31st of May

4. Flooding due to heavy rainstorm 31st of May

5. Flooding due to heavy rainstorm 31st of May
Office is 1 year old

6. Back home
Newly build sewer system in 2015

7. Stress test
Climate proof
stress test for
municipalities

8. Waterboard Rivierenland using Delft3D FM
Delft3D FM applications: Hazard Map of Rainfall induced Flooding
Levee breach scenario project

9. Model

10. Automatic grid refinement

11. Impact grid refinement

12. Analyze results
location: Breedeweg (Groesbeek)

13. Subgrid
post processing
• Post processing water depths
to DTM resolution (0.5x0.5 m)
using conservation of flood
volume.

14. Final product – Web Map

16. Visualizing results
Inspect model results in GIS:
• Water levels
• Water depths
• Flow velocities
• Stream lines
• Velocity vectors

17. Communication

18. Water safety: Levee breach scenarios
Uit: Leidraad voor het maken van Overstromingssimulaties,Deltares 2018
Februari 2018,
In opdracht van RWS-WVL en in samenwerking
met het Productieteam Kaarten van de ROR (de
EU Richtlijn Overstromingsrisico’s)

19. Scenario analyse dike ring Hoenzadriel

20. Start: Delft3D FM Meuse model
Developed as a sixth generation model for Rijkswaterstaat:
• Follow-up of the WAQUA models
• Concept developed in 2017; Implemented in 2018
Compute grid resolution:
8 cells in transverse direction summer bed
40 meters in length direction and in winter bed
Geometric data: from Baseline schematizations (j17)
Calibrated on different hydrographs: 2014 (Low), 2011 (Medium) and 1995 (High)
Boundary conditions: Hydrograph 4000 m3 / s (TMR2006)

21. Building the model grid

22. Levee breach

23. Flooding due to breach

24. Flow velocities

25. Comparison with existing scenarios
29 november 2018
No breach growth, instant width

26. Final remarks:
• Delft3D FM has added value in simulating rural flooding compared
to conventional modeling (SOBEK).
➢ More flexibility in generating model grid
➢ Better computational performance
➢ Higher level of detail
➢ Better options to visualize and communicate results
• Delft3D FM enables a more integrated modeling approach by
combining different domains (River - Rural – Urban) into one model
schematization.
This benefits our understanding of the water system and ultimately
should lead to better decision making in our climate change
adaptation efforts.