Tunnel: (Bridge Hunter; Satellite)
I spent more time than I care to admit looking at the Louisiana DOT web site to find information about these bridges. Lots of documentation of the nature "we will make plans." But very little information about what those plans were unless you count lists of closures and asphalt projects as plans.
Bus US-90 used to cross under the Harvey Canal south of the locks with a tunnel. Now it crosses over the canal with a pair of bridges. But the tunnel is still used for local traffic and pedestrians [OnlyInYourState]. I already studied a tunnel replacement with a high fixed bridge in Belle Chasse.
AAroads has a history of Bus US-90, but I could not find any info on these bridges. In particular, what is the clearance? They look a lot higher than barge traffic would require. When were they built?