Islets which are formed in rivers by the successive accumulation of relictions from above belong to the owners of the margins or banks nearest thereto, or to the owners of both banks if the island be situated in the middle of the river, in which case they will be divided longitudinally in half.If a single islet thus formed should be at a greater distance from one margin than from the other, the owner of the nearest margin shall be the sole and exclusive owner thereof. History —Law of Waters, art. 46.
Puerto Rico Legal Code