ERROR 117:
No cross section defined for Link xxx.
Error 117 : Cross section geometry was never defined for the specified link.
Quick Fix — Start Here
Locate the link identified in ERROR 117 and open its properties in GeoSWMM. Confirm that a cross-section shape and the required dimensions are defined. If the cross-section is missing, assign the appropriate geometry using project or source data, save the changes, and re-validate the model.
1. Description
ERROR 117 occurs during model validation when a link that requires cross-section geometry exists in the model but does not have a cross-section definition.
For a conduit, the cross-section defines the pipe or channel shape and the dimensions required for hydraulic calculations. Orifices and weirs also require appropriate opening geometry. Without this information, the SWMM engine cannot determine the link geometry needed for hydraulic routing, so the model cannot proceed until the missing cross-section is defined.
In GeoSWMM, conduit cross-section geometry is normally populated through the standard model-building workflow, using source data when available or default geometry where applicable. ERROR 117 can occur when a conduit is created or modified directly in ArcGIS Pro or the GeoSWMM project geodatabase and the required cross-section properties are left undefined.
2. Technical Background
SWMM engine requires applicable links to have a cross-section shape and the dimensions required for that shape. For example, a circular conduit requires a diameter, while a rectangular section requires the applicable height and width. Some cross-section types (e.g., irregular cross-section) reference another geometry object, such as a transect or custom shape.
Without geometry, SWMM cannot establish flow area, wetted perimeter, hydraulic radius, top width, or the link's conveyance and capacity. ERROR 117 therefore identifies a missing cross-section definition, not simply an incorrect dimension.
Figure 1. Example of defined versus missing cross-section geometry in EPA SWMM.
3. Resolution
Use the following checks to determine which length source applies to the conduit identified in the error message before making changes.
Likely Causes | What to Check |
|---|---|
Conduit added by manual GIS/geodatabase edit | The conduit was created directly in ArcGIS Pro's feature editor or by editing the GeoSWMM project geodatabase, bypassing GeoSWMM's normal creation workflow and its automatic cross-section population. |
Manually edited .inp file (standalone EPA SWMM) | A conduit or regulator link was added or altered by hand-editing the input file's [CONDUITS] or [XSECTIONS] section outside the SWMM interface. |
Inconsistent Link IDs | The link record and its cross-section record use different IDs, so SWMM cannot match them even though both exist. |
Orphaned records from merges or bulk edits | A model merge, bulk edit, or partial import left some geometry rows missing, blank, or disconnected from their link. |
3. Resolution
Start with the link identified in ERROR 117. Confirm whether the cross-section is missing, restore the required geometry, and then re-validate the model.
Table 1 : Troubleshooting steps
Step | Action | Why It Helps |
|---|---|---|
1 | Identify the flagged link
| Identifies the affected object and confirms the missing cross-section. |
2 | Define the required cross-section
| Provides the geometry SWMM needs for hydraulic routing. |
3 | Check the source data if the link was imported or created outside the standard GeoSWMM workflow
| Identifies missing or incomplete geometry caused by source-data, import, or direct geodatabase edits. |
4 | Verify referenced geometry where applicable
| Prevents a missing geometry reference from causing additional validation problems. |
5 | Save and re-validate the model
| Confirms that the cross-section definition is now complete and valid. |
Recommended Practice
When developing a GeoSWMM model from external GIS or model data, follow the standard GeoSWMM model-development workflow. This helps ensure that required model properties are populated consistently and reduces unnecessary manual editing. When importing link data, verify that the cross-section type and all required dimensions are correctly mapped for each applicable link.