Figure 5-7. Backfill compaction of CMP of 48 inches and over
HEADWALLS AND WINGWALLS
Headwalls and wingwalls are constructed to prevent and control erosion, guide water into the culvert, reduce
seepage, and hold the end of the culvert in place. These structures are costly in both time and materials. When
possible, to avoid expense, extend the outlet and use riprap and/or rubble at the toe of the slope. See figure 5-8.
Figure 5-8. Placement of riprap and rubble