Initialisation in InfoWorks CS

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July 2, 2014 | Raana Lang

Initialisation is a process where InfoWorks attempts to achieve a steady state in the system before simulation.  During initialisation the dry weather flow input starts at zero and gradually increases to the full value.  The full value is the sum of the first value in all dry weather inputs including population flows, trade flows, inflows and infiltration.  InfoWorks will continue to iterate until a steady state has been reached, i.e. InfoWorks continues to redefine values and re-calculates to an acceptable level of accuracy.  The steady state is defined by convergence criteria parameters listed under network / simulation parameters.  If for some reason the convergence criteria cannot be reached then initialisation continues ad infinitum, the model will not complete initialisation.

The most common reason for a model not initialising is due to flooding occurring in the model, oscillating volume or a never ending rise in level in some nodes.

The best way to check this is to let the network initialise for say 5 minutes and after that manually stop the Initialisation. Then follow this by stopping your simulation.

Now click on the manhole results grid button. The resulting grid can be sorted on flood volumes and should show the manholes that have flooded. From this we can try to determine why flooding is occurring at this location and stopping this flooding is the first step in trying to get the initialisation to complete.

The main issue will be that there is still a fluctuating flow in some area of the network. There is also a tolerance for volume balance field in the simulation parameters, both for the initialisation and for the simulation. Please ensure that these are set to the default value of 0.01 and make sure that you ticked these boxes in Simulation parameter dialogue box.

If your query persists please send the model to Innovyze Support ( in .iwc format for further investigation.

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Tags: modeling, initialisation

About the Authors

Raana Lang

Raana Lang

Technical Support


Raana is a technical support engineer working mainly with InfoWorks ICM. She has over 15 years of experience working with hydraulic models in the sewer space.