HY8:Inlet Configurations

You can select from the following inlet edge conditions which are available according to the selected culvert shape. The following inlet conditions are available (see drawing), but may not apply to all shapes or materials:

• Projecting
• Grooved end with headwall (0.05 X 0.07D)
• Grooved end projecting (0.05 X 0.07D)
• Square edge with headwall
• Beveled
• Mitered to conform with fill slope
• Headwall

The user can select only one inlet condition for each culvert. Detailed explanations of these inlet conditions can be found in FHWA Publication HDS No. 5 (2001) bundled with the program.

	This edge condition results in the end of the culvert barrel projecting out of the embankment.
	The grooved pipe is for concrete culverts and decreases the loss through the culvert entrance.
	This option is for concrete pipe culverts.
	Square edge with headwall is an entrance condition where the culvert entrance is flush with the headwall.
	'Beveled edges' is an improved inlet edge that decreases head loss as flow enters the culvert barrel.
	A mitered entrance is when the culvert barrel is cut so it is flush with the embankment slope.
	Wingwalls are used when the culvert is shorter than the embankment and prevents embankment material from falling into the culvert

• NOTE: HDS-5 notes that "Flared end sections made of either metal or concrete, are the sections commonly available from manufacturers. From limited hydraulic tests they are equivalent in operation to a headwall in both inlet and outlet control. Some end sections, incorporating a closed taper in their design have a superior hydraulic performance. These latter sections can be designed using the information given for the beveled inlet"