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 65m 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. A 2d_sa inflow is typically more stable in situations of fast model changes, for example, dam breaks.
   
   
   
   

Increment the 2d_bc layer from Part 1 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. Click on the ‘Increment Selected Layer’ symbol from the TUFLOW Plugin toolbar.
4. Update the 'Output Layer Name' to 2d_bc_M10_001_L.shp.
5. Click 'OK'.
   
6. The tool removes the source layer from the Layers panel and the 2d_bc_M10_001_L appears.
7. Right click on the '2d_bc_M10_001_L' layer to toggle on Editing.
8. Zoom into the upstream inflow, select and delete the line.
9. 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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