These are the major changes made in each release. For more details please see the commit log of the git repository.
Release date: 2025-08-06
This version introduces several practical improvements that make flood modeling more reliable and efficient. It adds support for water surface elevation and soil water content as direct inputs, implements real-time mass balance error tracking to prevent simulation issues, and saves complete drainage network results to the database. The update also fixes important bugs related to boundary conditions, mass balance calculations, and capillary pressure conversions, while improving the internal code structure for better maintainability.
Improvements
- Accept water surface elevation (terrain + water depth) as an input value (issue #27)
- Accept soil water content as an input value (issue #96)
- Mass balance error is now tracked in real time. The simulation will stop if the mass balance error is above a given threshold (issue #114)
- In the water depth maps exported to GRASS, the values under the threshold are no longer deleted, but exported and then masked with
r.null(issue #123) - The results for all the nodes and links of the drainage simulation are now saved to the database, not only those with coordinates.
- The output map "mean_losses* now has the same units (mm/h) as the input map losses.
- The distributed wheels are now targeting armv8-a and x86-64-v3. This allows better performance with NEON and AVX2 vector extensions. Most platforms less than 10 years old are compatibles. In case of incompatibilities, building from source remains an option.
- A wheel for Windows on ARM64 is now available.
Corrected bugs
- Fix the conversion factor of input capillary pressure (#132)
- Fix and improve the mass balance computation in the statistical file (issue #77)
- Open boundary condition is now properly applied on all domain boundaries (issue #41)
- The layer assignation for drainage links is now working correctly (issue #138)
Internals
- The reporting functionality is improved and better isolated. Memory output providers are added in addition to GRASS. (#112, #121, #125, #127, #129)
- Array names, description, units, etc. are now centralized (#134)
- Add benchmark for the tutorial (#113)
- Main surface flow functions in cython are better optimized for vectorization, with less branching and accepting only c_contiguous arrays. (#146)
- The boundary condition logic is now included into the Cython loop, instead of being done in python with numpy slices. (#151)
Release date: 2025-04-21
This is a modernized version of itzi. It implements the Basic Model Interface, allowing the coupling of itzi with other models. This version requires GRASS 8.4 or above.
Improvements
- Add compatibility with the Basic Model Interface.
Corrected bugs
- Fix the calculation of the Green-Ampt infiltration rate.
Internals
- This version now relies on pyswmm for the drainage coupling, instead of embedding the SWMM codebase.
- The code is now tested with Python 3.11 and above.
- Better code organization and refactoring.
- Remove the dependency on grass-session, as allowed by grass 8.4.
- More tests and better test coverage.
- Add a benchmark for the surface flow simulation.
- All internal units for infiltration are now m/s instead of mm/h, preventing conversion errors.
- More modern package tooling.
Release date: 2020-05-26
This version supports Python 3.7 and above, and therefore GRASS 7.8 and above. Python 2.x is no longer supported.
Improvements
- Raster maps are now written in the background. This might improve the performance in some cases.
Changes in the configuration file
- The "effective_pororosity" option is renamed to "effective_porosity". Using the former will raise a deprecation warning.
Corrected bugs
- Fix the stencil for 2D friction. This do not seems to have significant real-word impact.
- Computation time display is now working correctly when running simulations with the same filename.
- The first map of input inflow series is now taken into account.
- Raster masks are now properly taken into account.
Internals
- Python 3.7 or above is now mandatory.
- Refactoring of the code to follow a initialize-run-finalize model.
- Inclusion of a test suite to improve quality insurance.
- Use of grass-session to set the GRASS environment.
Release date: 2018-02-19
This new version of Itzï improves the stability of the surface-drainage coupling. The part of the code calculating the coupling has been mostly rewritten. The coupling flow between the surface and the drainage is calculated as follows:
- In case of drainage overflow, the orifice equation is used
- In case of surface to drainage flow, the coupling flow is calculated by using either the orifice, free weir or submerged weir equation. The equation is chosen according to the relative water surface elevations in the surface and the drainage, and the node crest elevation.
- If the water is entering the drainage network, the flow is limited to prevent negative depth in the surface model.
- The coupling flow cannot invert in one time-step. It must spend one time-step at zero. This reduces the oscillations that could occur when the water elevations in both the drainage network and the surface are similar.
Release date: 2017-11-24
New features
- Drainage coupling: Add the possibility to set the orifice and weir coefficients in the configuration file.
- Allow to set the raster mask and region from the input file.
- Now print an out-of-memory error message instead of a blank crash if the domain does not fit in the RAM.
Corrected bugs
- Drainage coupling: fix unit conversion problem in setting node fullDepth, set fullVolume at the same time.
Code organization
- Improve coding standard with pylint.
- Advance Python 3 support. Still limited by GRASS own incompatibility.
- Move more GRASS functions to gis.py.
Release date: 2017-10-27
Corrected bugs
- Fix problems of unit conversion in the interchange between the surface and the drainage model.
- Do not write the output vector maps if not wanted by the user.
- Fix a division by zero error appearing at the beginning of the simulation.
Release date: 2017-08-08
This is principally a bugfix release.
New features
- Flows interchanges when water is leaving the drainage network are always modelled with an orifice equation. This is in accordance with [1], from where the coefficients are taken.
Corrected bugs
- Fix the pip installation process. Remove the cython dependency.
[1] Rubinato et al. 2017. doi:10.1016/j.jhydrol.2017.06.024
Release date: 2017-07-31
This release adds the integration of the SWMM drainage network model.
New features
- Bi-directional coupling with the SWMM model
- Velocity is now calculated at the centre of the cells
- It is possible to output maps of the Froude number
- The maps of the initial state of the simulation are recorded
Changes in the configuration file
Some changes have been made to the configuration file in order to make the options clearer.
- In the [input] section, drainage_capacity is renamed losses
- In the [output] section, drainage_cap is renamed losses
If Itzï is run with an older option name, the user will receive a deprecation warning. Those legacy options are set for deletion in a later release. Please update your configuration files.
Corrected bugs
- Maps are recorded at the very end of the simulation
- Check if the domain is at least 3x3 cells before running a simulation.
- Itzï will check if grassdata, location and mapsets exist before running a simulation.
Release date: 2017-01-31
This is mainly a bugfix release
Corrected bugs
- Mass balance calculation now takes into account the volume from drainage capacity
- Volume error calculation is more accurate
New features
- Add the possibility to export the map of created volume from continuity error
- The %error column of the statistic output is now the percentage of the domain volume variation that is due to error
Release date: 2016-10-03
New features
- If multiple parameters files are given, they are run in a batch.
- Simulations can be run from outside GRASS.
- Add the possibility to set a drainage capacity map as entry data on top of infiltration parameters.
- The progress message is now more informative, giving the ETA and current simulation time.
Installation - NumPy is no longer installed by default. This prevents pip from installing a new version of NumPy even if another is already installed.
Release date: 2016-08-10
This is mainly a bugfix release.
Corrected bugs
- fix crash when using absolute time
- fix crash when not providing a statistics file name
- clearer message in case mandatory parameters are not set
New feature
- Allow display of CLI usage outside of GRASS environment
Release date: 2016-07-15
This is the first release of Itzï on Pypi
Easier installation
- Easy compilation and installation with pip
New user interface
- Parameters are now given only by configuration file
- Parameters name in configuration files are more explicit
- Output maps are now defined by a prefix and a list of output
- Add an example input file with parameter description
Corrected bugs
- Exit nicely if not run within GRASS environment
- Return an error if the input parameter files is not found
New features
- Export statistical maps for boundary flows, user inflow, infiltration and rainfall rates
Faster
- More tasks are run in parallel
- Minimize memory access
Known issues
- Open boundary condition is experimental and only tested on the East domain boundary.