Why could the Mississippi River potentially shift into the Atchafalaya River channel?

The Mississippi River has historically threatened to shift its primary flow into the Atchafalaya River because the Atchafalaya serves as a secondary channel that offers a shorter, steeper path to the Gulf of Mexico.12

If the Mississippi were to permanently divert into this channel, it would bypass New Orleans, inundate the lower Atchafalaya basin, and render existing flood-control infrastructure and port facilities useless. To prevent this natural geological tendency, the U.S. Army Corps of Engineers maintains a complex system of dams, locks, and the Old River Control Structures. These engineered works are essential to managing the river's delicate hydrology and ensuring the Mississippi remains in its current course.21