Tutorial M10 001 GIS Inputs QGIS

Introduction

QGIS is used to create, import and view input data.

TUFLOW Project Re-Configuration

Re-configure the TUFLOW project to use and save empty files to the correct folder:

1. Go to Plugins > TUFLOW > Editing > Configure / Create TUFLOW Project.
2. Change the folder which contains TUFLOW to the Module_10 folder. This is the only change required, the model folder structure and template empty files are supplied from previous model.
   Note: The 'results' and 'check' folder get automatically created when the TUFLOW model is run.
   
3. Click 'OK' and save the QGIS workspace by selecting Project > Save As.
   
   
   
   
4. Set the QGIS workspace projection to EPSG:32760, see Set the Projection.

Method

Navigate to the Module_10\Tutorial_Data folder. Copy the below GIS files into the Module_10\TUFLOW\model\gis folder:

• 2d_zsh_M10_damwall_001_L
• 2d_vzsh_M10_dambreak_001_R
• 2d_iwl_M10_001_R
• 2d_sa_M10_inflow_001_R

Investigate the supplied files:

1. Open the files, either:
   

   • Drag and drop all .shp files into the QGIS workspace, or
   • Select Layer > Add layer > Add Vector Layer and navigate to the Module_10\TUFLOW\model\gis folder.
     

2. The 2d_zsh line layer represents the dam wall:

   • A ‘Z’ attribute of 65 is specified, the elevations are set to 65 metres along the length of the line.
   • The line has the same Shape_Width as the cell size, this is a thick breakline modifying whole cells.

   
   
   
   
3. The 2d_vzsh polygon layer represents the location of the dam break:

   • Shape_Width_or_dMax set to less than zero indicates that the vertices along the perimeter of the polygon are used to interpolate elevations.
   • Trigger_Value sets the simulation time in hours that the dam break is to commence. A value of 1 indicates the dam break begins at 1 hour.
   • Period sets the time in hours over which the change in elevation occurs. A value of 0.25 sets a period of 15 minutes replicating the break.

   For more information, see Table 6-9 of the 2018 TUFLOW Manual.
   
   
   
   
4. The 2d_iwl polygon layer represents the initial water level of the dam as 59m at all cells within the polygon.
   
   
   
   
5. The 2d_sa layer replaces the 2d_bc QT type introduced in Module 1. A 2d_sa inflow is typically more stable in situations of fast model changes, for example, dam breaks.
   
6. Select the 2d_sa_M10_inflow_001_R in the Layers panel and use the 'Apply TUFLOW Styles to Current Layer' tool.
   
   
   
   

Increment the 2d_bc layer from Module 01 and remove the upstream inflow:

1. Navigate to the Module_10\model\gis folder and open the 2d_bc_M01_001_L in QGIS.
2. Select the 2d_bc_M01_001_L layer in the Layers panel.
3. Use the 'Apply TUFLOW Styles to Current Layer' tool.
4. Click on the ‘Increment Selected Layer’ symbol from the TUFLOW Plugin toolbar.
5. Update the 'Output Layer Name' to 2d_bc_M10_001_L.shp.
6. Click 'OK'.
   
7. The tool removes the source layer from the Layers panel and the 2d_bc_M10_001_L appears.
8. Right click on the '2d_bc_M10_001_L' layer to toggle on Editing.
9. Zoom to the upstream inflow, select and delete the line.
10. Click 'OK' and turn off editing to save the edits.
    
    
    

Conclusion

• A 2d_zsh layer was checked to enforce a dam wall in the model.
• A 2d_vzsh layer was inspected to simulate a break in the dam wall.
• A 2d_iwl layer was reviewed setting the initial water level within the dam upstream of the dam wall.
• The original upstream inflow was removed from the model, replaced by a source area boundary.

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