This document provides an overview of the Delft Software Days - wflow user day 2019. It introduces Pieter Hazenberg as the presenter and discusses his background. It then provides an agenda that will cover what wflow is, its latest features, applications, integration with other models, and future plans. The presentation engages the audience to discuss their interests and perspectives on wflow's limitations and improvements. It concludes by announcing the new wflow 2019.1 release and highlighting updated features including redesigns to the subsurface flow algorithm in wflow_sbm and addition of new hydrological models to the framework.

1. D e l f t S o f t w a r e D a y s - w f l o w u s e r d a y 2 0 1 9
Introduction to wflow concepts, Features &
developments, New release 2019.1
Pieter Hazenberg

2. wflow team
Product manager
Bobby Russel
Sr. Advisor – Inland water systems
Bobby.russel@deltares.nl
Software development lead
Dr. Willem van Verseveld
Sr. Advisor/Researcher – Inland water systems
Willem.vanVerseveld@deltares.nl
wflow development team
(including myself)
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3. Introduction
About myself
Name: Pieter Hazenberg, PhD
Current position: Sr. Researcher/Advisor at Deltares (since June 2019)
Specialties/Interests: Distributed hydrological modeling, wflow development, realtime to seasonal forecasting, precipitation,
hydrometeorological extremes, land-atmosphere interactions and climate change
Background:
2016-2019: Assistant Professor at the Department of Hydrology and Atmosperic Sciences, University of Arizona
2012-2016: Research Associate at the Institute for Atmospheric Physics, University of Arizona
2007-2012: PhD in Hydrometeorology in the Quantitative Water Management Group at Wageningen University
2004-2007: MSc in Hydrology and Water Quality at Wageningen University
2001-2004: BSc in Soil, water and Atmosphere at Wageningen University
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4. Introduction (Name and affiliation)
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5. Overview
1. What is wflow
2. What is distributed hydrological modelling
3. Latest features of the wflow hydrological modelling framework
4. Where is wflow being applied
5. How is wflow integrating with other models
6. How does the future look for wflow
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6. Question:
Lets make this session a little bit more interactive.
What are the first things that come to your mind when you think about wflow?
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7. What is wflow - Framework approach to distributed hydrological
modelling
Integration of different hydrological concepts
and cross-collaboration:
• wflow_pcrglobwb
• wflow_hbv
• wflow_sbm
• wflow_topoflex
• wflow_W3RA
• wflow_gr4
• wflow_stream
• wflow_sphy
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Application guide for the different modelling concepts.

8. Grid-based distributed hydrological modelling?
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9. High resolution hydrography data Upscaled model resolution hydrography
and subgrid river data
Global-wflow parameter estimation?
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10. Large-scale testing of global-wflow
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11. Features
• A sediment routing module (wflow_sediment)
• Water quality (wflow_emwaq and wflow_DELWAQ) - create and link a Delft3D-WAQ or D-Emissions model
to wflow_sbm
• A crop growth module (wflow_lintul) for irrigated rice dynamics
• Reservoirs and natural lakes routing
• Better routing – sub-grid river data from hi-res Merit Hydro data
• OpenDA (for data assimilation)
• Basic model interface (BMI) for coupling with other models
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12. 2018 – Completed projects
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13. 2019 – Rapid uptake
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14. Question:
For what would you like to make use of wflow? Which applications are you interested in?
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15. Stand-alone to greater integration
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• BMI allows wflow to be coupled
with other models
• Increasingly being used to
quickly generate headflows for
other applications
• Leveraging EartH2Observe
datasets for model building
• Hydro MERIT datasets

16. Stand-alone to integration
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Msimbazi flood modelling
project
National-level Drought and Flood Risk
Profiles in Sub-Saharan Africa
R&D to couple with wflow
for saturated zone
Sava River flood forecasting system
Suir River flood forecasting system
Community Water Watch
Water Resources Inventory of
the Republic of Azerbaijan
Knowledge and Innovation Support
for ADB’s Water Financing Program –
Myanmar Dry Zone Study
Geodata for upgrading small
holders' farming systems in
Indonesia (G4INDO)
SO - Integration of wflow and DELWAQ
(sediment, waste and water quality)
Water Quality Modelling Framework
for New Zealand
National Inventory, Metrics, and
Hotspots Assessment of Marine Plastics
Debris in Key Indonesian Cities
Seine River – tyre road wear
particles emission model

17. Question:
What limitation do you foresee for wflow and what would you like to see added/improved?
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18. The future – Priorities for wflow
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1. Improve hydrological concept
2. Need for speed​
3. Improve integration with other Deltares software products

19. 1 – Improve hydrological concept
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For wflow_sbm:
• Multiscale Parameter Regionalisation calibration module
• Kinematic wave in flat areas
• Soil depth
• Spatially distributed demand modules

20. 2 – Need for speed
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• Driven by demand – bigger domains, finer resolution, faster run times
• wflow provides head flows for other applications (water resources management, flood risk, flood warning, real-time control)
which need faster runtimes
• Possible solution: More efficient code
• Possible solution: Parallelization

21. 3 – Improved integration
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• Want an integrated modelling approach (with other tools)
• Driven by demand – wflow provides head flows for other applications (water resources management, flood risk, flood warning,
real-time control) which need time-step by time-step coupling
• Better ability to do scenario analysis

22. Deltares-4thinternationalwflowuserday
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Presenting…
WFLOW RELEASE 2019.01 !

23. Releasing wflow’s new version: wflow 2019.1
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Updated features
• wflow_sbm, redesign of lateral subsurface flow because of a bug that resulted in an overestimation of
lateral subsurface flux:
➢ The kinematic wave approach is used to route subsurface flow laterally
➢ Kinematic wave solution for surface (overland and river) and subsurface flow added to wflow_funcs, and
used by wflow_sbm. Numba (open-source JIT compiler) is used to accelerate these functions. This
replaces the PCRaster kinematic wave solution
➢ A seperate kinematic wave reservoir for river (self.RiverRunoff) and overland flow (self.LandRunoff)
➢ Lateral subsurface flow and overland flow feed into drainage network (channel) based on ratio slopes
(slope upstream cell / (slope upstream cell + slope cell))
➢ Option to provide land slope and river slope (staticmaps)
➢ Removed sub-grid runoff generation
➢ Removed re-infiltration of surface water
• wflow_hbv uses kinematic wave solution for surface flow available in wflow_funcs (replacement of PCRaster
kinematic wave solution)
• Option to enable iteration (smaller time steps) for kinematic wave solution for surface runoff (wflow_hbv
and wflow_sbm)

24. Releasing wflow’s new version: wflow 2019.1
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Updated features
We also have added:
• The hydrological model wflow_w3 to wflow framework, based on Australian Water Resources Assessment
Landscape model (AWRA-L), an improved version compared to wflow_W3RA
• The hydrological model wflow_stream to wflow framework (STREAM: Spatial Tools for River Basins and
Environment and Analysis of Management Options)
• An experimental version of wflow_sediment to simulate soil erosion and delivery to the river system
• The wflow_emwaq module: provides a set of functions to create and link a Delft3D-WAQ or D-Emission
model to a wflow model
• Update of lake modelling for wflow_hbv and wflow_sbm (including also Modified Puls Approach) in
wflow_funcs
• Update of glacier model (used by wflow_hbv and wflow_sbm)
• Parameter Manning N of river can be linked to streamorder for wflow_hbv
• setuptools_scm used for version wflow package

25. Question:
What do you hope to get out of today?
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26. Today’s programme
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27. back 
close 
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Thank you for your attention
Pieter.hazenberg@deltares.nl