2.0

Table Of Contents
Time of Concentration and Time of Travel
569
NOTE
When you are setting up the durations, enter the time in hours if your time
units are set to hours. If time units are set to minutes then you can enter
the time in minutes.
8 In an Intensity box, type the intensity value for the rainfall frequency you
selected. In the Intensity column, pick a text box and enter a value (such as 2
for 2 inches/hour). You can define as many intensities for the selected Rainfall
Frequency as you need.
9 Repeat steps 7 and 8 until you have entered duration and intensity data for all
your Rainfall Frequencies.
10 Click Save to save your information and click OK to return to the Rational
Method dialog box.
Other file options available from this dialog box include:
n
Insert Row: Inserts a new row above the selected row.
n
Delete Row: Deletes the selected row.
n
Delete Frequency: Deletes a rainfall frequency value.
n
Load: Opens an existing intensity-duration file. A standard AutoCAD file
open dialog box is displayed.
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New: Clears the data from the dialog box.
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View: Display a rainfall intensity versus duration curve. Outputs the data to
an ASCII .txt or .wk1 file, or plots the curve on a graph. For more
information, see Displaying a Graph of the Intensity-Duration Frequency
Data in this chapter.
Displaying a Graph of the Intensity-Duration
Frequency Data
The Intensity-Duration Frequency Curve graph displays the rainfall intensity
versus duration curve for a particular rainfall frequency.
To display a graph of rainfall intensity versus duration
1 From the Intensity Frequency Factor Editor dialog box, select the rainfall
frequency for which you want to plot a graph.
2 From the Rainfall Frequency list, select the rainfall frequency.
3 Click View to display the Intensity-Duration Frequency Curve dialog box which
shows the rainfall intensity versus duration curve for the rainfall frequency you
selected.
4 Click Plot to plot the curve on a graph, or click Output to output the data to an
ASCII .txt or .wk1 file.
5 Click Settings to change the appearance of the graph, such as the line colors.
6 Click Close to return to the Intensity-Duration Frequency Editor.
7 Click OK twice to exit the dialog boxes.