2.0

Calculating Runoff With the TR-20 Method
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To view and edit the dimensionless hydrograph values
1 From the Hydrology menu, choose Runoff ä TR-20 Method to display the SCS
TR-20 Unit Hydrograph Method dialog box.
2 Click Edit next to the Dimensionless Hydrograph list to display the
Dimensionless Hydrograph Editor dialog box.
3 You can use the options in this dialog box to review the values in an existing
dimensionless hydrograph, to edit these values, and to view the dimensionless
hydrograph curve. You can also load an existing dimensionless hydrograph file
or create a new file.
If you want to} Then}
edit the existing values use the navigation buttons to locate the line
you want to edit, and then type new values.
create a new dimensionless hydrograph
file
click New.
add a new range of time increments click Range.
add a new row place your cursor in the row you want to
add a new row above, and click Insert.
delete a row place your cursor in the row you want to
delete, and click Delete.
view the dimensionless hydrograph curve click View.
load an existing dimensionless
hydrograph file
click Load.
make sure that each value in a column is
greater than the next value
select the Ascend Check box.