XPSWMM Conversion Reconfigure SWMM Junctions

Update SWMM Nodes--Junctions Attributes

The following GIS feature updates to the Nodes--Junctions attributes will finalize the SWMM portion of the TUFLOW model. This is typically the final step in the model building process, as the recommended attributes for a junction node vary depending on whether the node is associated with inlet usage connections, 1D/2D culvert connections, and SWMM hydrology sub-catchments.

1. In the QGIS Layers panel, select (left click) Nodes--Junctions and toggle on editing.
2. In the Processing Toolbox, select the 'Edit Features In-Place' tool. This allows the editing of an existing layer, instead of the creation of a new layer.
3. Go to TUFLOW >> SWMM in the processing tool list and select the 'Junctions - Set attributes' processing tool. This opens the dialog shown below.

   • Input Subcatchment layers: If available, select Hydrology--Subcatchments.
   • Input Inlet Usage Layers: If available, select the inlet usage layer (e.g. swmm_iu_XP_001).
   • Input BC Connection Layers: If available, select the 2d_bc connection layer (e.g. 1D2D_Urban_001_2d_bc_L).
   • General Options:

   • Maximum Depth Option (Ymax): 'Leave as is (applies to edit in place only)'
   • Nodes receiving subcatchment flows option (if connected to 2D): 'Based on options selected below'

   • Nodes connected to 2D without Inlets (through embankment culvert):

   • Ysur: 0
   • Area of ponding: This value should match the 2D cell area associated with 1D/2D culvert connections (100 in the example dataset).

   • Nodes connected to 2D with Inlets (underground pipe network):

   • Maximum depth (Ymax) option: 'Use global option'
   • Ysur: 0
   • Area of ponding: This value should match the 2D cell area associated with the Inlet Usage connections (25 in the example model).

   • Nodes without 2D Connection (underground pipe network):

   • Surcharge Depth: This value should be a value higher than any expected water level in the model (99 in the example model).
   • Area of ponding: 1

4. Select 'Modify All Features'. Once the tool has finished, click 'Close'.
5. Turn off editing to save the edits.
6. View the attributes within Nodes--Junctions to verify the data processing has been completed correctly.
   For a summary of the attributes associated with the Nodes--Junctions layer, refer to TUFLOW 2023-03-AD Release Notes (Table A.30) and the SWMM Reference Manual - Volume 2 (Hydraulics).
   
   

   
   

Save the QGIS Workspace

In preparation for the next steps of the conversion process, ensure your QGIS workspace has been saved.

1. In QGIS, go to Project > Save from the top dropdown menu options.

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