User Notification: "The scenario failed to compute. Review your data and try again."

  Applies To 
  Product(s): SewerGEMS, StormCAD, SewerCAD
  Version(s): 08.11.XX.XX, 10.XX.XX.XX
  Area:  Calculations, Results and Output
  Original Author: Terry Foster, Bentley Technical Support Group


When attempting to compute a model with the GVF-Rational (StormCAD) solver,it fails with the following red User Notification:

"The scenario failed to compute.  Review your data and try again."


This is a generic error that could occur for multiple reasons.


Validate - First, use the Validate option to check for any obvious issues. Also, take a close look at the setup of the model and check for missing data or other problems.

Upgrade - Next, it's generally a good idea to have the most up to date version of the software. You can check for new versions in the Fulfilment Center. You can read more on that here:

How do I download the Water and Storm-Sewer hydraulics and hydrology products?

How can I find out when a new version or patch is available?

Narrow down - If the specific solutions below do not apply or do not resolve the issue, the next step would be to try to narrow down the problem by incrementally removing parts of the model. Save a copy of the model, then delete roughly half of it, in such a way that does not cause a network disconnection. Try computing again and if the error still occurs, continue removing more of the model. Once you get to the point where the error not longer occurs, use Undo to get back to the last state, and focus on the elements that were removed. Try deleting other sections of the model to further narrow it down, then take a close look at the connectivity and properties of the element(s) that you've narrowed it down to.

Case 1: Change the Road Cross Slope value to a number greater than zero.

  1. Open the FlexTable for catch basins.

  2. Make sure all on -grade catch basins have a value for Road Cross Slope greater than 0 on-grade catchbasins and greater than the road cross slope.

Case 2: Fix the irregular cross section input

One instance of this was caused by mistakenly setting a conduit section type to "Irregular Closed Section" and the data inputted for the section was in Station vs. Elevation format when the data was supposed to be entered in Elevation (Relative) vs. Width. The conduit was supposed to be set to a section type of "Irregular Channel".


  1. Go to Components > Inlet Catalog. Click each inlet and click the "design" tab. Make sure you do not have a length of zero in the table of
    available design lengths.


  2. Open the properties for the conduits that are setup incorrectly by double clicking on the conduit link in the drawing pane. Adjust the input data accordingly

Case 3: Create user defined IDF Table from IDF Curve Equation data

Another instance of this was fixed by creating a user defined IDF Table from the duration and intensity values provided by the IDF Curve Equation.

Case 4: Check for combination of 3D length and headwall as outfall

If this occurs and you're using a headwall node as an outfall (Boundary Condition Type set to Free outfall or user defined tailwater) with the "3D length" option enabled in Tools > Tools > Options, you may be encountering known issue # 624509. To resolve this, either change the end node to an outfall, disable the 3D length option, or upgrade to CONNECT Edition SELECTseries 1 or greater, when available.

Case 5: Check for user defined conduits using the "Modified Basket Handle" section type

If the rise of conduit is less than one-half of the span use a different conduit shape or change the values for the conduit. The equation specifically states the rise be greater than or equal to one-half of the span.  The conduit shapes are listed in the help document that comes with the software. The user notification for this conduit shape will be fixed in a future version of the software.

Case 6: Check for pipes missing nodes

Run the query "pipes missing nodes" under the Network Trace section of Network Navigator. A pipe missing an end node could potentially cause this issue in some cases. Delete any identified pipes and re-draw. If using the AutoCAD platform, try opening the model in Standalone first before running the query.

Case 7: Check for combination of the use of gutter depth vs. captured flow inlet type with the trapezoidal gutter shape.

In version of StormCAD, SewerGEMS and CivilStorm and in Subsurface Utilities/SUDA V8i SELECTseries 4, the above combination can cause the error in question (reference defect # 694565). This has been resolved in the latest cumulative patch set for (and SUDA V8i SS4). It is also resolved in later versions of these products. Please contact technical support for help with the patch, or use a different type of inlet of gutter shape if possible.