The water table in LA is ludicrously high. That might pose a problem with underground lines.
CC
Yeah. Cemeteries inter people above ground.
Eventually, as it has many times in the past, the Mississippi will find a new course to the sea, probably to the north of Baton Rouge mostly along the Atchafalaya River. This would put the Mississippi's new outlet to the Gulf at Morgan City, Louisiana, a route that has the benefit of being 193 miles shorter, steeper, and faster than the current course through New Orleans.
This would make New Orleans into a secondary port at best, without ready access by ship and barge to the upper river.