The inlet end of the pipe should be extended so that a minimum sized headwall is required. On steep grades, a
headwall is necessary at the outlet side to hold the culvert sections in place. Headwalls should not protrude above
the shoulder grade and should be located at least two feet outside the shoulder to avoid being traffic hazards.
Wingwalls are required to channelize water and prevent washing out of headwalls. Their height should prevent
embankment material from spilling into the waterway. Figure 5-9 illustrates three types of headwalls.
Figure 5-9. Three types of headwalls