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Table Of Contents
Time of Concentration and Time of Travel
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Specifying a Rational Runoff Coefficient
You can enter the runoff coefficient that represents the ratio of runoff to rainfall
using the Rational Method dialog box.
To specify a rational runoff coefficient
1 From the Rational Method dialog box, click Coef to display the Rational
Coefficient File Selection dialog box.
2 Select the file type to use (Land Uses or Soil Types). The Rational Coefficients
dialog box is displayed for the file type you selected.
3 Select a value from the Rational Coefficients dialog box by clicking in a field
that contains a value, and then click OK.
Use the navigation keys (located to the right of the dialog box) to move through
the data that isn't visible on the screen.
4 The value you selected from the Rational Coefficients dialog box is placed in the
Coef. column of the Rational Method dialog box.
Specifying a Composite Runoff Coefficient
You can use the Composite Runoff Coefficient Calculator dialog box to select a
composite runoff coefficient. This editor dialog box shows you runoff curve
numbers for a variety of soil and land use combinations. You can edit the
settings based on your personal standards.