Tute M08 MI Rainfall

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Introduction

This page details the method of using MapInfo to create the GIS layers that will apply direct rainfall to the entire model extent. Once this layer has been setup, a new boundary conditions database will be created linking the object within the GIS layer to a hyetograph.

Method

GIS Layers

  1. Open an empty 2d_rf layer from the TUFLOW\model\mi\empty folder and save a copy as 2d_rf_M08_001 to the TUFLOW\model\mi folder. Close the 2d_rf_empty file.
  2. We will be applying the direct rainfall over the whole 2D model area. To do this, open the 2d_code_M04_001 layer created in Module 4. Select the code polygon within the 2d_code_M04_001 layer and copy it. Ensure 2d_rf_M08_001 is editable and selected, and paste the code polygon from the 2d_code layer within it.
  3. Open the attribute table of 2d_rf_M08_001 and populate the polygon with the following data:
    Name f1 f2
    RF_loc_001 1 1


    A detailed description of the attributes of the 2d_RF layer can be found in the 2010 TUFLOW Manual. Using these attributes, we are setting:

    • The name of the rainfall hyetograph that will be referenced in the boundary conditions database
    • A multiplier that adjusts the rainfall due to spatial variations in the total rainfall. Note that specifying a value of zero will cause zero rainfall to be applied to the model.
    • A second multiplier that allows for adjusting the rainfall spatially. As for the F1 attribute, a value of zero applies no rainfall to the model.
  4. Save and export the layer to MID/MIF format.
    M08 2d rf.png

Boundary Condition Database

  1. Copy the contents of Module_data\Module_08 into the TUFLOW\bcdbase folder.
  2. Open the existing boundary conditions database bc_dbase_M07.csv within the TUFLOW\bc_dbase folder. Save it as bc_dbase_M08.csv.
  3. Delete the four rows referencing the inflow hydrographs from the 2d_sa_M07_001_R layer (inflows called Loc_001, Loc_002, Loc_003 and Loc_004) and the row referencing FC04. Add another row to the bc_dbase with the following information:
    Name Source Column 1 Column 2
    RF_Loc_001 100yr2hr_rf.csv time RF_Loc_001


  4. The row we have added links the name of the 2d_rf polygon to the hyetograph stored within the file 100yr2hr_rf.csv. Note that the input data is in mm versus hrs and not mm/hr versus hrs. The new bc_dabase should look like the figure below:
  5. Now we will change the inflow hydrographs applied to the river to a suitable baseflow amount. For inflows FC01 and FC02, change the source csv file from 100yr2hr.csv to baseflow.csv.
    M08 bc dbase.png

  6. Save the bc_dbase. It is now ready to be used within the model.


Conclusion

A GIS layer has been created to apply rainfall over the model extent. The existing boundary conditions database has been modified to link the polygon within this GIS layer to a hyetograph stored within an external csv file. The inflow hydrograph previously applied to the river has been substituted with a baseflow. Please return to the main page of module 8.