Art. 463. Whenever the current of a river divides itself into branches, leaving a piece of land or part thereof isolated, the owner of the land retains his ownership. He also retains it if a portion of land is separated from the estate by the current. (Civil Code)
Does the rule apply if the river is non-navigable?

The rule applies whether the river is navigable or not, for in both  cases, the owner should not be deprived of his dominion over the segregated or isolated property.


Reference:
Edgardo L. Paras, Civil Code of the Philippines Annotated, Book II, Property