Evaluate the hydraulic effects of floodplain encroachments for the peak discharges of the design AEP and the 1% AEP on any major highway facility.

Avoid relocation or realignment of a stream channel wherever practicable.

Match the cross-sectional shape, plan-view, roughness, sediment transport, and slope to the original conditions insofar as practicable.

Include some means of energy dissipation when velocities through the structure are excessive or when the original conditions cannot be duplicated.

Provide stream bank stabilization, when appropriate, to counteract any stream disturbance such as encroachment. Stabilize both upstream and downstream banks, as well as the local site. Refer to “Stream Stability at Highway Bridges,” for guidance.

Provide a sufficient top width with access for maintenance equipment for features such as dikes and levees associated with natural channel modifications. Provide turnaround points throughout and at the end of these features.