Itzï 17.7 is released

31 July 2017 • Laurent Courty

After several months of development, the version 17.7 of Itzï is available on the Python package index. The exciting news is the integration of the SWMM drainage network model. Itzï can now model a drainage network and the interactions with the surface model. The documentation will be updated soon to take into account this new version.

Drainage network integration

Itzï now integrates with SWMM. The two models exchange mass at the drainage nodes that are inside the modelling area. The drainage network that is actually modelled could be larger that the GRASS raster mask, but the mass interchange will only occurs at the nodes inside the raster modelling region. The results from the network model are exported as a GRASS space-time vector dataset. Itzï uses weir and orifice equations to calculate the flow exchange between the drainage and the surface.

Changes in configuration file

This new feature induces some changes in the configuration file.

First, the drainage capacity option is renamed to losses. This option could be used in a more general way and keeping that name could have created some confusion.

  • 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.

Second, a new [drainage] section is added, were the SWMM INP file and the output STVDS are set.

Other new features

  • 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

Corrected bugs

  • Maps are recorded at the very end of the simulation
  • Itzï will verify 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.

Update to the new version

To update your installation to the last version, type the following in the command line:

pip install -U itzi