TUFLOW SWMM Tutorial M01

Introduction

In this module, three culverts are added to represent flow through three separate road embankments. EPA SWMM is used as the solution scheme for the 1D culvert flow calculations, dynamically linked with the TUFLOW HPC 2D solution scheme.

TUFLOW SWMM Tutorial Module 1 builds from the model created in TUFLOW Tutorial Module 2 (in the TUFLOW Only tutorial dataset). The completed Module 2 model is provided in the TUFLOW_SWMM_Module_01\TUFLOW folder of the download dataset as the starting point for this tutorial. If you are not already familiar with TUFLOW, we recommend first completing Module 1 and 2 of the "TUFLOW Only" Tutorials to establish an understanding of 2D modelling, before progressing to learning how to link 1D EPA SWMM to 2D TUFLOW.

QGIS Project Initialization

1. Open QGIS. QGIS Version 3.34 or newer, and QGIS TUFLOW Plugin 3.9.0.49 or newer are required to access the SWMM Processing Tools described in the following sections:
2. Establish the Coordinate Reference System (CRS), also know as "Projection", for the session.
   • Select Project >> Properties... from the top drop menu options.
   • Select CRS, filter for CRS 32760, Select WGS84 / UTM Zone 60S.
   • Click Apply and OK.
   
3. Select the Load TUFLOW Layers from TCF button .
4. Style the TUFLOW Layers to suit your own preference. Common steps to do this are:
   • Clicking the Apply TUFLOW Styles to Open Layers button .
   • Applying Hillshade symbology to the DEM dataset.
   

SWMM Inputs and 1D/2D Linking

Create SWMM GeoPackage Spatial Database

1. Create a new folder in the TUFLOW_SWMM_Module_01\TUFLOW\model folder called swmm. This is the location where all SWMM inputs will be saved.
2. Open QGIS and select Processing >> Toolbox from the top drop menu options to open the Processing Toolbox panel.
3. From the TUFLOW >> SWMM processing tool list, select GeoPackage-Create.
   
4. Within the GeoPackage-Create options, set the following:
   • CRS for GeoPackage = Project CRS: EPSG:32760 - WGS 84/UTM zone 60S
   • Initial SWMM Sections, click on the ... button, then select: Title, Options, Nodes-Junctions, Nodes-Outfalls, Links-Conduits, Streets, Inlets, Report
   • GPKG file name to create, click on the ... button, select Save to File.... Navigate to the newly created swmm folder and set the SWMM GeoPackage Spatial Database name to TS01_001.gpkg
   • Select Run. After the processing task is complete, select Close.
5. Open the new SWMM GeoPackage Spatial Database in QGIS by dragging and dropping TS01_001.gpkg from Windows Explorer into QGIS. When prompted by QGIS select "Add Layers" to open all vectors within the GeoPackage database. By default, all items in the available list should have been selected.
   

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GIS Data Entry

Navigate to the TUFLOW_SWMM_Module_01\Tutorial_Data folder in Windows Explorer. Drag and drop SWMM_Culverts.gpkg into QGIS to open the file. SWMM_Culverts.gpkg includes three Layers, Links-Conduits, Nodes-Junctions and Nodes-Outfall. Links-Conduits defines the culvert location, type and geometry. Nodes-Junction define the upstream culverts inverts. Nodes-Outfall define the downstream culvert inverts.

Complete the following steps:

1. Copy the objects from Links--Conduits SWMM_Culverts.gpkg into Links--Conduits TS01_001.gpkg. Steps to Copy/Paste are as follows:
   • Left click Links--Conduits SWMM_Culverts.gpkg in the QGIS Layers Panel. Right cick the Layer and select Zoom to Layer if the three objects within the layer are currently not displayed in the main Map Window.
   • Use the select the Feature by Area tool to select all items included in Links--Conduits SWMM_Culverts.gpkg
   • Select Edit >> Copy Features
   • Left click Links--Conduits TS01_001.gpkg in the QGIS Layers Panel.
   • Select Toggle Editing to enable changes to be made to the Layer.
   • Select Edit >> Paste Features

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1. Copy the objects from Nodes--Junction SWMM_Culverts.gpkg into Nodes--Junction TS01_001.gpkg. Junctions are considered inlets, and should be defined at the upstream end of culverts.
2. Copy the objects from Nodes--Outfall SWMM_Culverts.gpkg into Nodes--Outfall TS01_001.gpkg. Outfalls are treated as outlets, and are required at the downstream end of culverts.
3. Close SWMM_Culverts.gpkg
4. Inspect the attribute information within the respective layers to familiarize yourself with the data.

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GIS Data Updates

The provided GIS data requires numerous updates, prior to our model simulation. We have built these updates into this tutorial to demonstrate some of the available TUFLOW SWMM model built processing tools.

The following updates are being made to Objects and Layers within TS01_001.gpkg

Update Conduit Details

Step 1 involves updating the From Node and To Node attribute information in Links-Conduits. This information is necessary to "build" the 1D SWMM network. It defines the Link/Node connections. The information we will be adding to Links-Conduits is extracted from Nodes--Junction and Nodes--Outfall automatically using the Conduits - Assign Node Fields tool from the Processing Toolbox.

1. Select (Left mouse click) Links--Conduits in the QGIS Layers panel and Toggle Editing on.
2. From the Processing Toolbox, select "Editing in place". This allows the editing of an existing Layer, instead of the creation of a new Layer.
3. Select the Conduits - Assign Node Fields processing tool.
4. Select Nodes--Junction and Nodes--Outfall in the SWMM Node Layers field.
5. Select Modify All Features.
6. Close the Conduits - Assign Node Fields processing tool.
7. View the attributes associated within Links-Conduits to verify the data processing has been completed correctly. The From Node and To Node attribute information is now configured correctly.

Tip: If you wish to only update select objects during a future modelling project, instead of the entire Link--Conduits dataset, select the target objects first using the Feature by Area tool. The Conduits - Assign Node Fields tool will provide an option to Modify Selected Features, instead of Modify All Features.

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Update Losses

Step 2, update the loss attributes in the Links-Conduits Layer. These values will be entered manually in this example using default values. Variation to the default values can be used in project models to reflect site specific information if desired.

1. Select (Left mouse click) Links--Conduits in the QGIS Layers panel and Toggle Editing on.
2. Right mouse click Links--Conduits in the QGIS Layers panel and select Open Attribute Table.
3. Set:
   • losses_Kentry = 0.5
   • losses_kexit = 1.0
   • losses_Kavg = 0.0
4. Save Links--Conduits

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An urban pipe network is added to the model in TUFLOW SWMM Module 2. In that situation, different loss attributes are required for the road culverts and underground stormwater pipe network links. To simplify the loss attibute update step in that situation, we will be introducing the Conduits - Assign Node Fields processing tool. It is however, not necessary for this Module 1 tutorial because all the 1D SWMM inputs are embankment culverts.

Create 1D/2D Connections

The following instructions introduce a new tool that automates the creation of 1D/2D connections. For 1D SWMM, HX lines are required from the upstream end of the culvert, and SX connections are used at the downstream end of the culvert.

1. Select (Left mouse click) Links-Conduits in the QGIS Layers panel.
2. Use the select the Feature by Area tool to select all culvert objects in Links-Conduits.
3. In the search box of the Processing Toolbox panel, type SWMM.
4. From the SWMM list, choose the BC - Create channel endpoint 1D/2D connections.
5. Select the following options:
   • Input Conduits Layer = Links Conduits
   • Offset distance = 2
   • Length of BC lines = 10
   • Output Layer= Select: Save to GeoPackage. Choose TS01_001.gpkg in the model\swmm folder and click Save. A Layer Name Window will open. Provide the following name: 2d_bc_SWMM_Connections_001_L.
     

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Update Junction Details

1. Select (Left mouse click) Node--Junctions in the QGIS Layers panel and Toggle Editing on.
2. From the Processing Toolbox, select "Editing in place". This allows the editing of an existing Layer, instead of the creation of a new Layer.
3. Select the Junctions - Set attributes processing tool. Select the following:
   • Input bc connections layer = 2d_bc_SWMM_Connections_001_L
   • Nodes connected to 2D without Inlets (Ysur ) = 0
   • Nodes connected to 2D without Inlets (Apond ) = 50
4. Select Modify All Features.
5. Close the Junctions - Set attributes processing tool.
6. View the attributes associated within Node--Junctions to verify the data processing has been completed correctly.

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SWMM Options

1. Select the Options Layer in TS01_001.gpkg file.
2. Select Toggle Editing to enable changes to be made to the Layer.
3. Right click the Layer in the Layers Panel and select 'Open Attribute Table'.
4. Update the following option:
   • Start Date: 01/01/2020 (USA Date Format: MM/DD/YYY)
   • Report step: 00:05:00
5. Save and Toggle Editing off.

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Export SWMM INP File

SWMM does not read TS01_001.gpkg directly as an input GIS file. SWMM requires a INP file

1. Right click Links--Conduits in the QGIS Layers panel, and select TUFLOW >> SWMM - Export inp file.
2. Select TS01_001.gpkg as the GeoPackage Input File.
3. Set the SWMM output filename to TS01_001.inp in the TUFLOW/model/swmm folder.
4. Select "Run", then "Close" after the processing is complete.

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Simulation Control Files

TUFLOW Boundary Control File (TBC)

To differentiate the TUFLOW SWMM tutorials from the TUFLOW/ESTRY tutorials, TS will be used as the new file prefix in this series of tutorials.

1. Save M01_001.tbc as TS01_001.tbc in the TUFLOW_SWMM_Module_01\TUFLOW\model folder.
2. Open TS01_001.tbc in a text editor and add the additional lines:
   Spatial Database == swmm\TS01_001.gpkg
   Read GIS BC == 2d_bc_SWMM_Connections_001_L ! Links the 1D culverts to the 2D domain
   
3. Save the TBC.

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TUFLOW SWMM Control File (TSCF)

A new control file, the TUFLOW SWMM Control File (TSCF), is introduced. SWMM is a 1D hydraulic solver. All 1D SWMM files and commands are referenced in the TUFLOW SWMM Control File.

1. Create a new text file called TS01_001.tscf, saved in the TUFLOW_SWMM_Module_01\TUFLOW\model folder.
2. Add the following command lines:
   Read SWMM == swmm\TS01_001.inp ! 1D SWMM input file
   
3. Save the TSCF.
   

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TUFLOW Control File (TCF)

1. Save a copy of the M02_5m_001.tcf as TS01_5m_001.tcf in the TUFLOW_SWMM_Module_01\TUFLOW\runs folder.
2. Open the TS01_5m_001.tcf in a text editor:
   Add the following line in the 'Model Inputs' section:
   SWMM Control File == ..\model\TS01_001.tscf ! Reference the SWMM (1D) Control File
   Add the following line in the 'Output Settings' section:
   NetCDF Output Start Date == 2020-01-01 00:00 ! Sets the output units for the NetCDF time variable
   
3. Make the following reference update:
   BC Control File == ..\model\TS01_001.tbc ! Reference the TUFLOW Boundary Conditions Control File
   
4. Save the TCF.

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Running the Simulation

1. Save a copy of _run_M02_HPC.bat as _run_TS01_HPC.bat in the TUFLOW_SWMM_Module_01\TUFLOW\runs folder.
2. Update the batch file to reference the TS01_5m_001.tcf :
   set exe="..\..\..\exe\2023-03-AD\TUFLOW_iSP_w64.exe"
   set run=start "TUFLOW" /wait %exe% -b
   %run% TS01_5m_001.tcf
3. Double click the batch file in Windows file explorer to run the simulation.

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If your model simulation did not run. Here is a link to some comon Tutorial Trouble Shooting advice.

Check Files and Results Output

Complete the steps outlines in the following link to review check files and simulation results from the TUFLOW SWMM model simulation:

TUFLOW SWMM Tutorial 01 Check Files
TUFLOW SWMM Tutorial 01 Results

Conclusion

• EPA SWMM Culverts were added to convey water through the structures under the three roads in the tutorial model.
• Check files were used to review the application of the boundary links.
• Results through the 1D network structures were assessed.

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