3Di pilot application in Taiwan

1. 3Di pilot application in Taiwan
Geert Prinsen (Deltares)
Jhih-Cyuan Shen (NTUT-TaipeiTech)
Yung-Chia Hsu (NCTU-DPWE)
October 28, 2015

2. Content
 What is 3Di?
 Flood modeling
 In the cloud
 Interactive
 Fast and accurate
 FEWS Taiwan
 3Di pilots in Taiwan
 Meifu
 Sanyei
 3Di and FEWS
- possible use cases 3Di and FEWS

3. What is 3Di?
Modeling the outdoor space and its water systems
• Propagation of floods / disaster management
• Spatial Planning
• Stakeholder participation
• Communication

4. What is 3Di?
“State of the Art” hydraulic modeling
Comprises a number of innovative, interrelated developments
• Interactive calculations
• Calculation in the cloud
• Accurate and fast
• Realistic visualization

5. High resolution data Details make the difference
elevation, land use etc.

6. Lidar and visualisation

7. Realistic visualisation

8. Next Generation: Computation in the Cloud
Vinyl records Compact Discs MP3
Your music models
available
at any device
at any time

9. Next Generation: Computation in the Cloud
Your models available
at any device
at any time
Engineers in the office
(computer)
Decision makers
during a meeting
(touch table)
Disaster response
teams in the field
(tablet, smartphone)

10. Next Generation: Sharing ideas and knowledge
Engineers team up
with urban planners
to interactively design
better life
environment
Water is one of the
spatial structures in
spatial planning

11. Next generation: 3Di
Imagine what you would do when your models are:
− Readily available on any device (pc, tablet, smartphone)
− Fast, accurate and visual enough to use in discussions with
decision makers, urban planners, …
− Interactive and adjustable on the spot (stop-change-start) e.g.
during a meeting
− Reproducible

12. 3Di: Law of Physics
North Sea
Petten

13. Sub-grid method: compute flow friction on DEM-pixels, but fast flood
predictions on coarse grids.
Quad tree technique : enables local grid refinements by recursively
subdividing cells into four quadrants
Digital Elevation Model as sub-grid
3Di: Sub-grid and Quad tree technique

14. 3Di: Law of Physics
Professor Dr. Ir. Guus Stelling
“The world is rapidly being pixelized”
“First we had models but no data,
now it is the other way around”

15. 3Di is essentially three innovations
Main concepts 3Di
• Better and much faster with sub-grid and
quad tree technique (10-1000x faster
than conventional schemes), using
detailed pixelized data.
• Make live changes to your model
(interactive stop-change-start), see effect
of measures directly.
• Realistic visualization
• good communication tool.

16. The development of FEWS-Taiwan - since 2003
26 Rivers:RR+CF

17. Rainfall Gauges to Grid Display
Accumulated precipitation is 1346 mm in 2 days

18. Data sources in FEWS-Taiwan
Real time data stations
• Rain gauge: 744
• Water level: 209
• Reservoirs : 11
• Radar: 6-1
( 1 lost in 2015 Typhoon Soudelor )
• Tide : 38
Image from :
http://img1.cna.com.tw/www/WebPhotos/Chart/20150810/31221615.jpg

19. Urban flooding more and more important
Image from: Google Earth

20. 3Di case study: MeiFu, Taiwan; Typhoon Saola
Typhoon Saola
In MeiFu 500 mm rainfall in 4 days
Upstream almost 2000 mm

21. MeiFu: 3Di model using High resolution 1x1m DEM
DEM: 1x1 m, ~27.8 million grid pixels, ~17m difference in elevation over 11km
26 observation locations for a post-disaster maximum flood depth survey

22. MeiFu: SOBEK 1D2D model using 10x10 and 20x20m DEM

23. MeiFu: Examples of 3Di calculation grid

24. MeiFu: Satellite image
Satellite image of the flood taken on August 2, 17:51PM (GMT+8hr)

25. MeiFu: Satellite image combined with SOBEK results
SOBEK 1D2D flood extent on top of satellite image

26. MeiFu: Satellite image
Satellite image of the flood taken on August 2, 17:51PM (GMT+8hr)

27. MeiFu: Satellite image combined with 3Di results
3Di flood extent on top of satellite image

28. 3Di live site

29. 3Di pilot: Sanyei area in Tainan, southern Taiwan

30. About 250 mm of rain in 13 hours

31. Some pictures

32. Land use Infiltration capacity

33. Friction Boundary condition

34. 3Di DEM preparation
- 2D calculations only, no 1D elements included in the model
- Burned-in canals, sewer pipes
- 10x10m DEM and 1x1m DEM

35. Detailed comparison of flooded area SOBEK – 3Di
國道一號
1
3
2
1 1
SOBEK 3Di
2 2
SOBEK 3Di
3 3
SOBEK 3Di

36. Comparison of results
Grid Option
minimum cell
size ( )
Maximum nr
of levels
(lmax)
Number of
computational
elements
Simulation
solution
time (s)
Grid 1 (10x10m DEM based) 40 3 2437 157
Grid 2 (10x10m DEM based) 20 4 3454 254
Grid 3 (10x10m DEM based) 10 5 5644 501
Grid 4 (10x10m DEM based) 5 6 10358 1375
Grid 5 (1x1m DEM based) 40 3 2461 180
Grid 6 (1x1m DEM based) 20 4 3499 281
Grid 7 (1x1m DEM based) 10 5 5750 568
Grid 8 (1x1m DEM based) 5 6 10553 1395
SOBEK (10x10 m grid) 428519 68771
Conclusion: Good preparation of the DEM and proper modelling of 1D elements is important!

37. How We Want to Use 3Di in FEWS-Taiwan
In The Design Case:
• WRA start 3rd Taiwan Flood Risk map project
6 hour(mm) 12 hour(mm) 24 hour (mm) Return period
(year)
Rainfall
Design
50, 100, 150,
200, 250, 300,
350, 400, 450,
500
100, 150, 200,
250, 300, 350,
400, 450, 500,
550
150, 200, 250,
300, 350, 400,
450, 500, 550,
600
2, 5, 10, 25, 50,
100, 200, 500
Boundary
source
Sewer system, Drainage system
flood control facilities (Dam, flood pond and pumping station ),
Wave volume, storm surge
DEM ≤ 40m ( 5m , 10m , 20m )
Project Model is based on SOBEK model

38. How We Want to Use 3Di in FEWS-Taiwan
In the real event case
• Typhoon and/or Monsoon Event
Observation Forecasting
Rainfall
source
Radar Rainfall
Gauge Rainfall
NWP (WRF Ensemble ,
STMAS, ETQPFS)
Boundary
source
Sewer system, Drainage system
Flood control facilities (Dam, flood pond and pumping
station)
storm surge
DEM ≤ 40m ( 5m , 10m , 20m )

39. Coupling of 3Di to FEWS
Combine strong points of FEWS with strong points of 3Di
- FEWS: historical (observed) and forecasted timeseries
- FEWS: scheduling of runs, comparison with earlier runs
- FEWS: data validation/analysis
- etc.
- 3Di: fast and accurate computational core
- 3Di: running in the cloud
- 3Di: visualisation
- Etc
- Who is in control?

40. Standard FEWS – model coupling

41. Use case 1: FEWS - 3Di stand-alone
- Just like any other computational module under FEWS, use the
general adapter and put the 3Di computational core under FEWS.
- Provide input (boundary time series) from FEWS to 3Di
computational core.
- Import the results from 3Di in FEWS and visualize them in FEWS.

42. Use case 2: FEWS - 3Di in cloud
Is similar to use case 1, ‘only’ 3Di is running in the cloud.
- Run the 3Di cloud model from the FEWS GUI
- Provide input (boundary time series) from FEWS to 3Di.
- Import the results from 3Di in FEWS and visualize them in FEWS.
Issues to deal with when 3Di runs in the cloud:
- How does FEWS (or you) know the model is still running?
- How to provide the data to the pre-adapter?
- How to start the adapters and 3Di model? (Web-services, API, .. )
- How to use the interactive features of 3Di running in the cloud?
- How to do immediate real-time visualization in FEWS?
- etc.

43. Use case 3: FEWS - 3Di stand-alone + measure
Similar to use case 1, but including measures or what-if scenarios
- Run the 3Di cloud model from the FEWS GUI
- Provide input (boundary time series) from FEWS to 3Di.
- Provide additional input (measure): update DEM or other model
parameters
- Import the results from 3Di in FEWS and visualize them in FEWS.

44. Use case 4: FEWS - 3Di cloud + measure
Similar to use case 2, but including measures or what-if scenarios.
(Or, similar to use case 3, but in the cloud instead of stand-alone)
- Run the 3Di cloud model from the FEWS GUI
- Provide input (boundary time series) from FEWS to 3Di.
- Provide additional input (measure): update DEM or update other
3Di model parameters
- Import the results from 3Di in FEWS and visualise them in FEWS.

45. Use case 5: FEWS - 3Di, stand-alone presentation
- As use case 1 and 3
- Improve presentation of 3Di results in FEWS-displays

46. Use case 6: FEWS - 3Di Live site presentation
Link 3Di Live site to FEWS Archive (model results)
- 3Di live site for presentation of 3Di model results
- Link 3Di live site to FEWS-Archive to get and show previous
model results
- 3Di Live site extension to be able to distinguish various
scenarios

47. Use case 7: 3Di Live site with FEWS database
Link 3Di Live site to FEWS Archive (input)
- Live site to do calculations using observed and predicted time
series from FEWS (Archive)
- Read and present 3Di results in 3Di Live site
- Link 3Di live site to FEWS-Archive to get, show and use model
input

48. Use case 8: FEWS-3DI Cloud + external model
Couple FEWS and 3Di to external models
- Based on adapter from use case 4 (FEWS-3Di cloud and
measure)
- Extend adapter to allow coupled models
- Input data from FEWS
- Presentation in FEWS (like case 1-5) or 3Di live site (7)

49. Conclusion
3Di has attractive features:
• fast and accurate flood modelling,
• in the cloud,
• Interactive,
• visualization
How to couple FEWS and 3Di?
• Different use cases, stand-alone vs in the cloud
• Coupling in the cloud has some challenges
• We are thinking about the possible use cases
• We are open for your suggestions!

50. The End
Thank you.
Questions and discussion