View source for Tute M08 QGIS Rainfall Archive

==Introduction==
This page details the method of using QGIS 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.  <br>

==Method==
===GIS Layers===
<ol>
<li>Open an empty 2d_rf layer from the '''TUFLOW\model\gis\empty''' folder and save a copy as 2d_rf_M08_001_R to the '''TUFLOW\model\gis''' folder. Close the 2d_rf_empty_R file.<br>  
<li>We will be applying the direct rainfall over the whole 2D model area. To do this, open the 2d_code_M04_001_R layer created in Module 4. Select the code polygon within the 2d_code_M04_001_R layer and copy it. Ensure 2d_rf_M08_001_R is editable and selected, and paste all objects from the 2d_code layer within it.
<li>Open the attribute table of 2d_rf_M08_001_R and populate the polygon with the following data: <br>

{| align="center" class="wikitable" width="30%"
! style="background-color:#005581; font-weight:bold; color:white;"| Name
! style="background-color:#005581; font-weight:bold; color:white;"| f1
! style="background-color:#005581; font-weight:bold; color:white;"| f2

|-
|RF_loc_001|| 1 || 1
|}
<br>
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.<br>
<li>Save the layer.
<br>
[[file:M08_2d_rf.png|500px]]
</ol>
===Boundary Condition Database===
<ol>
<li>Copy the contents of '''Module_data\Module_08''' into the '''TUFLOW\bcdbase''' folder.
<li>Open the existing boundary conditions database bc_dbase_M07.csv within the '''TUFLOW\bc_dbase''' folder. Save it as bc_dbase_M08.csv.
<li>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:<br>

{| align="center" class="wikitable" width="50%"
! style="background-color:#005581; font-weight:bold; color:white;"| Name
! style="background-color:#005581; font-weight:bold; color:white;"| Source
! style="background-color:#005581; font-weight:bold; color:white;"| Column 1
! style="background-color:#005581; font-weight:bold; color:white;"| Column 2

|-
|RF_Loc_001 || 100yr2hr_rf.csv  || time ||RF_Loc_001 
|}


<li>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:<br> 
<li> 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.
<br>

[[File:M08_bc_dbase.png|350px]]<br>
<br>

<li>Save the bc_dbase. It is now ready to be used within the model.<br>
</ol>

==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. [[Tutorial_Module08_Archive#GIS_and_Model_Inputs | Please return to the main page of module 8]].