The imod 6 project aims to develop a new version of the imod software based on Modflow 6, enhancing capabilities for multi-model simulations and cooperation with USGS for robust improvements. It targets various user groups including hydrologists and water managers, focusing on modernizing software architecture and facilitating detailed regional and global modeling. Future developments will emphasize user community participation, joint investments, and integrating advanced features like parallel computation and model coupling.

1. i M O D U s e r D a y – D S D - I N T 2 0 1 9
The iMOD 6 project
Otto de Keizer

2. Introduction
• iMOD based on MODFLOW computational core
• MODFLOW 6 developments urged us to start
rethinking iMOD
• The iMOD 6 project: development of a new iMOD
version based on MODFLOW 6
• R&D and pilot projects with MODFLOW 6
• Cooperation with USGS and user groups
• Elaboration architecture and start developments
• Initial financing with Deltares R&D funds, but future
investments from water sector will guide
development efforts.
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3. Main reasons for iMOD 6 development
1. Currently MODFLOW-2005 used in iMOD;
MODFLOW6 provides significant advances:
a. Improved (recoded) computational core
b. Support for multi-model simulations, so no need to
adapt MODFLOW code for use in iMOD
c. Added capabilities for nested and unstructured
modelling
d. Full integration of SEAWAT (fres-salt) and water
quality (MD3T) packages
2. Cooperation with USGS provides
opportunities for more robust and sustainable
enhancements (e.g. parallisation, model coupling)
3. Need to modernize and improve
maintainability and support of the iMOD
software in closer cooperation with the
Deltares Software Centre.
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4. Ambition
Our ambition is that iMOD 6 becomes an open-source user interface and tool for
model development and applications that combines the strengths of iMOD and the
core functionality of the MODFLOW 6 computational kernel.
• Facilitate an active international user community
• Regarding MODFLOW6 no separate development line but developments in cooperation with USGS
• Cooperation with USGS currently includes:
• Parallelization of computational kernel
• Interface for model couplings
• Contribution to computational framework
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Interesting for the Netherlands
• Modelling regional detail, including nature reserves, drinking
water production, rivers
• Modelling upper layers in more detail than deeper layers
(e.g. based on Geotop data)
• Detailed numerical modelling of piping in dikes and other
local geotechnical issues
• Include precise locations of abstractions in model
• Combine regional and local models, e.g. with dike section
• Improved performance of large scale detailed models

6. … and internationally
• Develop multi-scale models, e.g. including river basin and delta in
one model;
• Model complex geological formations
• Model potential solutions for drought issues
• Model subsidence in delta areas
• Surface water – groundwater interactions
• Improved performance of global (groundwater) models
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Subsidence Mekong Delta (Vietnam)
IWRM Cauca Valley, Colombia

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Target groups iMOD 6
• Advisor and expert (geo)hydrologist / modeller;
• Water manager (national, regional)
• Drinking water companies and industry
• Geologist
• Geotechnical engineer

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iMOD 6: three components
1. MODFLOW computational core (USGS in lead)
2. iMOD Modelling Tool for the MODFLOW modeler
3. iMOD Windows GUI/App for the MODFLOW model user
and the (interactive) visualization of data and results
--------------------------
Also ‘external’ developments, e.g.
1. Model workflow manager
2. DSS platform & Dashboard
3. Effect Modules
iMOD 6
MODFLOW 6
iMOD GUIiMOD Tool
Workflow
Manager
Dashboard(s)
MetaSWAP
Other
hydrological
models

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iMOD 6
ModellerModel user
E.g. Simulate the effects
of climate scenarios on
future groundwater levels
E.g. Set-up and calibrate
numerical groundwater
model
E.g. Simulate the effects
of climate scenarios on
future groundwater levels
E.g. Set-up and calibrate
numerical groundwater
model

10. iMOD 6
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iMOD tool
Import/Export
Calibration
Validation
Model set-up
Data interfaces to e.g.
Delft-FEWS
iMOD GUI / App
Basic editor
Workflow viewer
3D viewer
4D viewer
Input verification
Model viewer
MODFLOW 6
computational
kernel
iMOD Backend
Fresh – Salt water
Quality
Subsidence
Hydrodynamics Model couplings
Mesh generation
Parallellisation
Data model
(Meta)SWAP

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Focus 2020
iMOD6
Architecture
Maintenance
and support
MODFLOW6
coupling with
(Meta)SWAP
MODFLOW6
(structured) in
iMOD5
iMOD6 GUI
(unstructured / nested)
iMOD6 Toolbox
Project plan for 2020 in
development
Focus on development
of minimal viable
product
User needs and use
cases basis for
developments

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Participation of user community
• (International) user days and user meetings in the Netherlands
• iMOD user forum at oss.deltares.nl
• Bilateral meetings with interested parties
• Joint investments
• Steering group with representatives from most relevant user groups and donors

13. Conclusions
• MODFLOW6 has the future, MODFLOW2005 will be outphased and developments focused on iMOD6;
• Deltares provides initial funding from R&D funds, investments from water sector will be relevant to guide future developments
• Your contributions and recommendations (e.g. regarding key needs and uses) are very welcome!
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• In 2019:
• Identification of user needs and priorities for developments
• Architecture and project plan for developments 2019 (minimum viable product)
• Identify interest for joint investments (possibly combined with govermental subsidies)
• In 2020 focus on:
• MODFLOW6 (structured) in iMOD5
• New user interface for unstructured and nested models
• MODFLOW6 coupling with (Meta)SWAP
• Development iMOD6 Toolbox for modeller
• Maintenance and support

14. back 
close 
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Thank you for your attention!
Deltares
Otto de Keizer
Otto.deKeizer@deltares.nl