Accretion formed successively and imperceptibly on the bank of a river or stream, whether navigable or not, is called alluvion. The alluvion belongs to the owner of the bank, who is bound to leave public that portion of the bank which is required for the public use.
The same rule applies to dereliction formed by water receding imperceptibly from a bank of a river or stream. The owner of the land situated at the edge of the bank left dry owns the dereliction.
La. C.C. § 499