One of the reasons that Innovyze implemented Scenario functionality in InfoWorks ICM is because there were some complaints about the process of exploring alternatives in ICM’s predecessor InfoWorks CS that we wanted to improve. In InfoWorks CS, any alternative to the Base network that was explored would require a new network. These alternatives were branched off from their parent network, sometimes creating large trees of networks. This was frustrating for a few reasons:
- This would often result in a large tree of networks, making it difficult to find the network alternative that you wish to work with. And cleaning up this tree of networks was difficult because if a parent network were deleted, all of its children (or branched networks) would have to be deleted.
- If a mistake were corrected (such as an incorrect pipe diameter) in a parent network, this correction would not get implemented in branched networks, so each network in the potentially very large tree of networks would need to be corrected.
Scenarios in InfoWorks ICM allow you to explore network alternatives without creating a brand new network. This solves the first problem mentioned above. By creating the scenario alternatives within a network, extraneous networks and complicated network trees are eliminated, AND when changes are made to the Base scenario (previously ‘parent’ network), the change gets perpetuated in all scenarios as long as the inheritance has not been broken (see ICM Help topic ‘Scenarios’ for details about inheritance rules). This solves problem #2 mentioned above.
Some examples of alternatives that you may wish to explore with Scenarios:
- Master Plans for future years
- RTC strategies
- Pipe size changes
- I/I Reduction
- Designs for reducing overflows
- Sensitivity analysis (With SQLs, you can automatically add scenarios and then, for example, increase/decrease roughness by 10% for sensitivity analysis, for example see our video Using SQL queries to automate processes in InfoWorks ICM.
When used appropriately, the scenario functionality is very useful. But there are some common mistakes when managing scenarios that you should keep in mind.
1. Too many scenarios – A scenario is essentially a copy of the entire Base network. So, if your Base network is large and you have too many scenarios, this can really affect the performance of both opening the network and uploading a simulation to a Remote Agent. Therefore, scenarios should NOT be used to build your model using a different scenario for each stage of the model build. It is recommended that you use the version control and commit history to do this as this approach only saves the changes between each successive commits. We also recommend that extraneous scenarios be deleted using the Scenario Manager and that this clean-up of scenarios be performed often.
2. Adding objects to a scenario that were previously deleted – Once objects have been deleted in a scenario, there is only one way to add them back to the scenario without causing problems in the network file. Here are the steps to add objects back to a scenario that were previously deleted:
a. Activate the scenario where you want to add the objects that were previously deleted
b. Use the ‘Excluded objects grid’ to view all deleted objects
c. To restore all excluded (or deleted) objects to the scenario, use the ‘Restore excluded objects’ button
d. If you only wish to restore a few excluded objects, unfortunately, there is no current easy way to do so. Please note that Innovyze has plans to improve this in an upcoming release of ICM, but is not included currently (v8.5). For now, you will have to restore all objects, then re-delete the ones that you do not want to include in the scenario. One way to do this:
- Before restoring all excluded objects from the scenario, open the ‘Excluded objects grid’ and make note of the objects you wish to restore to the scenario.
- Clear any selection in the network, then create a new Selection List and name it something like ‘objects to delete from scenario.’
- Right-click on the new Selection List and select ‘Open As’
- Select the ‘Grid view’ option and click ‘OK’
- Copy all items from the ‘Excluded objects’ grid into the Selection List grid except for the items that you want to restore to the scenario. Pay close attention to the tabs in both the ‘Excluded objects’ grid and the Selection List grid to make sure you are including all objects that will need to be deleted from the scenario
- Close both grids
- Restore all objects to the scenario
- Drag the Selection List onto the GeoPlan
- Delete the selected objects
- QA/QC the restored/deleted objects in the scenario before you commit your changes.
3. Changing object’s geometry or ID in a scenario – Object IDs and Geometry can only be changed in the Base scenario. In a scenario, if you want an object moved to another location or its ID changed, then the workaround is to delete the object that you want moved and add a new element placed where you wish or named as you wish that will be unique to that scenario.
4. Wrong assumptions about inheritance – One common misunderstanding is that even if a scenario is created based on a copy of other one, it does not inherit anything from the scenario from which it was copied. It still only inherits from the Base scenario. This is shown in the following figure:
As mentioned previously, please see the ‘Scenarios’ topic in the ICM Help for more details on the inheritance rules of scenarios.
If you have any questions about managing scenarios in InfoWorks ICM, please contact support (firstname.lastname@example.org) so that we can provide guidance on the best way forward.