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Table Of Contents
Chapter 5 Working with Hydrology Commands
596
Calculating the Peak Runoff by Using the
TR-20 Method
To calculate the peak runoff using the TR-20 Method
1 From the Hydrology menu, choose Runoff รค TR-20 Method to display the SCS
TR-20 Unit Hydrograph Method dialog box.
TIP
To load a runoff calculation that you previously saved, click Load.
2 In the Description text box, enter a description for this watershed area.
3 From the Dimensionless Hydrograph list, select a dimensionless hydrograph.
The SCS hydrograph, scsdim.dim, is supplied for you.
You can also click Edit to display the Dimensionless Hydrograph Editor dialog
box, where you can view and edit an existing dimensionless hydrograph file, or
create a new file.
4 From the Distribution list, select a TR-20 distribution curve table: tr20t1, tr20t2,
tr20t3, tr20t4, tr20t5, tr20t6, or tr20t7.
You can also click Edit to display the Distribution Editor dialog box where you
can edit the distribution values.