Diagnostics and tips for linked river and urban simulations

If you are struggling to get your integrated model to run to completion, the model diagnostics will help you pinpoint the cause of the problem. The locations of these messages vary:

• User interface - a pop-up window will appear to indicate a problem.
• Running a simulation via the UI - the simulation window contains a log of all the messages from the engines.
• 1D river engine - the messages are in files with extension lf1 and/or zzd.
• 2D engine - the messages are in files with extension lf2 and/or log.
• 1D urban engine - the messages are in a file with extension rpt.
• TUFLOW - the messages are in a file with extension tlf.

General tips

If time allows, test running each component of your linked model individually to check how stable each model is.
A 1D river only model may require a higher “glass wall” to account for there not being anyway for overtopping flows to go to (ensure this is changed back for the linked version).

Tips on integrating urban networks and river networks

A general checklist of some considerations when integrating to urban networks is as follows:

Ensure you 'Allow Ponding'. This is necessary to allow flow back into the urban network if connecting to anything other than an outfall node. A 'Ponded Area' must also be set. You will be warned by software if there is a large difference in the ponded area compared to the area of the linked aspects.

Are your nodes compatible? Recall the default river and urban link (flow into the river) can be used for outfall, flow divider or junction nodes, connected to river section nodes. The alternative link option (flow out of the river) requires a HTBDY connected to flow divider. junction or storage node.

Use dynamic wave routing for the urban model. Ensure 'Use Variable Timesteps' in NOT checked. This is always necessary for integrating to river networks or 2D.

Timesteps: 1D timesteps should match! Or at least multiples of each other. If linking to 2D, we recommended the 2D timestep is twice that of the 1D. Set your start and finish times as absolute values to match the details in the urban network.