Check the Industrial Canal. It has (at least one) set of locks, and that canal communicates between the lake and the river.
The Bonnet Carre Spillway is opened by lifting creosoted timbers out of place. It isn't made up of "doors" the way a lock is. I doubt the Bonnet Carre' Spillway is open at all.
Early reports (read: "rumor") had the spillway locked open. Credible press reports so far have only stated that a "lock" is stuck in the open position.
Thanks for helping rule out the spillway.