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Table Of Contents
Calculating Culvert Size and Shape
491
2 From the Runoff Editor dialog box, click Select button next to the File box to
display the Runoff Method Selection dialog box.
3 Do one of the following to calculate flow:
n
Click Rational to load a .rat file or to use the Rational Method calculator. For
more information, see Calculating the Peak Runoff Flow for an Area Using
the Rational Method in this chapter.
n
Click Tabular to load a .tab file or to use the TR-55 Tabular Hydrograph
Method calculator. For more information, see Calculating the Peak Runoff
Using the TR-55 Tabular Method in this chapter.
n
Click Peak Discharge to load a .gpm file or to use the TR-55 Graphical Peak
Discharge Method calculator. For more information, see Calculating the
Peak Runoff Flow by Using the TR-55 Graphical Method in this chapter.
n
Click Inflow Hydrograph to load a .hdc or .wk1 file. For more information,
see Specifying the Flowrate Using a Hydrograph (.hdc) File in this chapter.
n
Click TR-20 Method to load an .scs file or to use the SCS Unit Hydrograph
Method calculator. For more information, see Calculating the Peak Runoff
Using the TR-20 Method in this chapter.
4 Click OK to return to the Runoff Editor dialog box. The flow value displays in
the Runoff Editors Flow field.
5 Click OK to return to the Culvert Design dialog box. The flow value displays in
the Culvert Design Flow field.
Specifying the Flowrate Using a Hydrograph
(.hdc) File
You can choose a flowrate for a culvert using a hydrograph (.hdc) file from a
data table. The data table comes with default settings that you can customize.
To specify the flowrate for a culvert using a hydrograph (.hdc) file
1 From the Runoff Editor dialog box, click the Select button next to the File box
to display the Runoff Method Selection dialog box.
2 Click Inflow Hydrograph to display a standard load file dialog box.
3 Select the file you want to load. You can load either .hdc or .wk1 files.
4 Click OK to return to the Runoff Editor dialog box.