Presentation by Hélène Boisgontier (Deltares) at the Seminar Models and decision-making in the wake of climate uncertainties, during the Deltares Software Days South-East Asia 2023. Wednesday, 22 February 2023, Singapore.

1. Hélène Boisgontier
Ümit Taner, Peter Gijsbers, Tjalling de Jong, Jaap Langemeijer
Homero Alejandro Paltan Lopez
Online, open-source toolbox for rapid
bottom-up climate risk assessment
22 February 2023
Climate Stress Testing
Toolbox

2. 2
Conventional
approach
(predict → act)
What would the
future be?
(projections)
Seek optimality
How would the
system respond?

3. 3
Conventional
approach
(predict → act)
Bottom-up
approaches
What would the
future be?
(projections)
Seek optimality
How would the
system respond?
What are
vulnerabilities?
(stress testing)
Seek robustness
How concerned
shall we be?
(climate-informed
likelihoods)

4. World Bank used bottom-up approaches in lending
and analytical work (2015-2021)
4
Lessons learned
• Require specific knowledge
(PhDs) and lots of effort
• Not easily done with common
modeling software
• Access to data is a problem
• …

5. Online, open-source toolbox for rapid bottom-up
climate risk assessment
• Developed for general practitioners & analysts (GUI)
• Open-source software on the cloud, no installation necessary
• Readily linked to common climate datasets (CMIP6, ERA5, CHIRPS)
• Initially developed to assess hydrological risks (droughts and/or floods)
5

6. What the tool will do:
1. Create a project virtually anywhere in the world and rapidly build a distributed hydrology
model
2. Explore climate uncertainty from historical data & GCM* information
3. Design and execute a climate stress test to explore hydrological outputs across a wide
range of futures
4. Interactively assess vulnerabilities and risk with user-defined thresholds and GCM
information
6
*Global Climate Model

7. Voettekst
van
de
presentatie
8
1. Generate many weather series to
explore natural variability & climate
change (weather generator)
2. Simulate hydrological response to
those weather conditions (wflow)
3. Reveal conditions leading
vulnerabilities – conditions causing
problems based on critical thresholds
4. Assess the plausibility of
vulnerabilities using climate-
information
Weather
Generator
1
Climate stress testing

8. Voettekst
van
de
presentatie
9
1. Generate many weather series to
explore natural variability & climate
change (weather generator)
2. Simulate hydrological response to
those weather conditions (wflow)
1. Simulate hydrological response to
those weather conditions (wflow)
2. Reveal conditions leading
vulnerabilities – conditions causing
problems based on critical thresholds
3. Assess the plausibility of
Weather
Generator
1
Climate stress testing
Hydrology model
(wflow)
2

9. Voettekst
van
de
presentatie
10
1. Generate many weather series to
explore natural variability & climate
change (weather generator)
2. Simulate hydrological response to
those weather conditions (wflow)
3. Reveal conditions leading
vulnerabilities – conditions causing
problems based on critical thresholds
1. Simulate hydrological response to
those weather conditions (wflow)
2. Reveal conditions leading
Weather
Generator
1
Climate stress testing
Hydrology model
(wflow)
2
3
Climate
response
surface

10. Voettekst
van
de
presentatie
11
1. Generate many weather series to
explore natural variability & climate
change (weather generator)
2. Simulate hydrological response to
those weather conditions (wflow)
3. Reveal conditions leading
vulnerabilities – conditions causing
problems based on critical thresholds
4. Assess climate-informed risks using
GCM projections (or other information)
Weather
Generator
1
Climate stress testing
Hydrology model
(wflow)
2
Climate
response
surface
GCM
Projections
3 4
+

11. Software used within the Climate Stress
Testing toolbox
12

12. 13
*Adopted from Steinschneider et al. (2013)
HydroMT
model builder interface
https://github.com/Deltares/hydromt
https://github.com/Deltares/Wflow.jl
WFLOW
Distributed hydrological model
Multi-grid weather generator*
https://github.com/Deltares/weathergenr
Main tools used in CST toolbox

13. Weather generator
14
• Generates multi-grid, multi-
variable daily time-series
• Preserve historical statistics:
• Multi-year wet/dry patterns
• First & higher-order statistics (mean,
variance, skewness etc.)
• Temporal/spatial correlations

14. Weather generator
Perturb desired climate statistics to impose climatic changes
• Means conditions (annual/seasonal)
• Variability and extremes (annual/seasonal)
• Transition probs. between wet and dry states
15

15. Wflow
16
• The Deltares open-source hydrological
modelling framework
• Used for catchment-scale rainfall-runoff
modelling
• Fully distributed (grid-based)
• Physics-based
• Open-source & free:
• Source code (Julia:
https://github.com/Deltares/Wflow.jl)
• Pre-compiled versions availble for
registered users (.exe)

16. HydroMT
HydroMT (Hydro Model Tools) is an open-source Python
package at the interface between data, users, and water
system models.
Builds and updates inter-connected environmental
models for hydrology, water quality, groundwater,
water resources and environmental impacts applications.
Anywhere in the world.
Using global and/or local data.
In a fast and reproducible way.
17

17. GUI illustration
18

18. Voettekst
van
de
presentatie
19
Dashboard
projects
2. Select climate
data
3. Setup hydro
model
4. Assess model
goodness-of-fit
5. Design stress
test experiment
6. Assess
climate-informed
risks
1. Define project
area

19. 20
Dashboard
projects
2. Select climate
data
3. Setup hydro
model
4. Assess model
goodness-of-fit
5. Design stress
test experiment
6. Assess
climate-informed
risks
1. Define
project area

20. Voettekst
van
de
presentatie
21
Dashboard
projects
2. Select
climate data
3. Setup hydro
model
4. Assess model
goodness-of-fit
5. Design stress
test experiment
6. Assess
climate-informed
risks
1. Define project
area

21. Voettekst
van
de
presentatie
22
Dashboard
projects
2. Select climate
data
3. Setup hydro
model
4. Assess model
goodness-of-fit
5. Design stress
test experiment
6. Assess
climate-informed
risks
1. Define project
area

22. Voettekst
van
de
presentatie
23
Dashboard
projects
2. Select climate
data
3. Setup hydro
model
4. Assess
model
goodness-of-fit
5. Design stress
test experiment
6. Assess
climate-informed
risks
1. Define project
area

23. Voettekst
van
de
presentatie
24
Dashboard
projects
2. Select climate
data
3. Setup hydro
model
4. Assess model
goodness-of-fit
5. Design stress
test experiment
6. Assess
climate-informed
risks
1. Define project
area

24. Voettekst
van
de
presentatie
25
Dashboard
projects
2. Select climate
data
3. Setup hydro
model
4. Assess model
goodness-of-fit
5. Design stress
test experiment
6. Assess
climate-
informed risks
1. Define project
area

25. Status of the tool
• Final design of the interface
• Start testing together locally with the World Bank in Cambodia and South Africa
• Migrate the tool to the cloud
• Tests with World Bank users
• Future: open the tool to stakeholders and practicionners
26

26. Thank you for your attention